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Diffstat (limited to 'mailnews/mime/jsmime')
| -rw-r--r-- | mailnews/mime/jsmime/LICENSE | 19 | ||||
| -rw-r--r-- | mailnews/mime/jsmime/README.md | 59 | ||||
| -rw-r--r-- | mailnews/mime/jsmime/jsmime.js | 3300 |
3 files changed, 3378 insertions, 0 deletions
diff --git a/mailnews/mime/jsmime/LICENSE b/mailnews/mime/jsmime/LICENSE new file mode 100644 index 000000000..9ddc547d9 --- /dev/null +++ b/mailnews/mime/jsmime/LICENSE @@ -0,0 +1,19 @@ +Copyright (c) 2013 Joshua Cranmer + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +THE SOFTWARE. diff --git a/mailnews/mime/jsmime/README.md b/mailnews/mime/jsmime/README.md new file mode 100644 index 000000000..a418516ea --- /dev/null +++ b/mailnews/mime/jsmime/README.md @@ -0,0 +1,59 @@ +Code Layout +=========== + +JSMime is a MIME parsing and composition library that is written completely in +JavaScript using ES6 functionality and WebAPIs (where such APIs exist). There +are a few features for which a standardized WebAPI does not exist; for these, +external JavaScript libraries are used. + +The MIME parser consists of three logical phases of translation: + +1. Build the MIME (and pseudo-MIME) tree. +2. Convert the MIME tree into a list of body parts and attachments. +3. Use the result to drive a displayed version of the message. + +The first stage is located in `mimeparser.js`. The latter stages have yet to be +implemented. + +Dependencies +============ + +This code depends on the following ES6 features and Web APIs: +* ES6 generators +* ES6 Map and Set +* ES6 @@iterator support (especially for Map and Set) +* ES6 let +* ES6 let-destructuring +* ES6 const +* Typed arrays (predominantly Uint8Array) +* btoa, atob (found on global Windows or WorkerScopes) +* TextDecoder + +Versions and API stability +========================== + +As APIs require some use and experimentation to get a feel for what works best, +the APIs may change between successive version updates as uses indicate +substandard or error-prone APIs. Therefore, there will be no guarantee of API +stability until version 1.0 is released. + +This code is being initially developed as an effort to replace the MIME library +within Thunderbird. New versions will be released as needed to bring new support +into the Thunderbird codebase; version 1.0 will correspond to the version where +feature-parity with the old MIME library is reached. The set of features which +will be added before 1.0 are the following: +* S/MIME encryption and decryption +* PGP encryption and decryption +* IMAP parts-on-demand support +* Support for text/plain to HTML conversion for display +* Support for HTML downgrading and sanitization for display +* Support for all major multipart types +* Ability to convert HTML documents to text/plain and multipart/related +* Support for building outgoing messages +* Support for IDN and EAI +* yEnc and uuencode decoding support +* Support for date and Message-ID/References-like headers + +Other features than these may be added before version 1.0 is released (most +notably TNEF decoding support), but they are not considered necessary to release +a version 1.0. diff --git a/mailnews/mime/jsmime/jsmime.js b/mailnews/mime/jsmime/jsmime.js new file mode 100644 index 000000000..253b5da0f --- /dev/null +++ b/mailnews/mime/jsmime/jsmime.js @@ -0,0 +1,3300 @@ +(function (root, fn) { + if (typeof define === 'function' && define.amd) { + define(fn); + } else if (typeof module !== 'undefined' && module.exports) { + module.exports = fn(); + } else { + root.jsmime = fn(); + } +}(this, function() { + var mods = {}; + function req(id) { + return mods[id.replace(/^\.\//, '')]; + } + + function def(id, fn) { + mods[id] = fn(req); + } +def('mimeutils', function() { +"use strict"; + +/** + * Decode a quoted-printable buffer into a binary string. + * + * @param buffer {BinaryString} The string to decode. + * @param more {Boolean} This argument is ignored. + * @returns {Array(BinaryString, BinaryString)} The first element of the array + * is the decoded string. The second element is always the empty + * string. + */ +function decode_qp(buffer, more) { + // Unlike base64, quoted-printable isn't stateful across multiple lines, so + // there is no need to buffer input, so we can always ignore more. + let decoded = buffer.replace( + // Replace either =<hex><hex> or =<wsp>CRLF + /=([0-9A-F][0-9A-F]|[ \t]*(\r\n|[\r\n]|$))/gi, + function replace_chars(match, param) { + // If trailing text matches [ \t]*CRLF, drop everything, since it's a + // soft line break. + if (param.trim().length == 0) + return ''; + return String.fromCharCode(parseInt(param, 16)); + }); + return [decoded, '']; +} + +/** + * Decode a base64 buffer into a binary string. Unlike window.atob, the buffer + * may contain non-base64 characters that will be ignored. + * + * @param buffer {BinaryString} The string to decode. + * @param more {Boolean} If true, we expect that this function could be + * called again and should retain extra data. If + * false, we should flush all pending output. + * @returns {Array(BinaryString, BinaryString)} The first element of the array + * is the decoded string. The second element contains the data that + * could not be decoded and needs to be retained for the next call. + */ +function decode_base64(buffer, more) { + // Drop all non-base64 characters + let sanitize = buffer.replace(/[^A-Za-z0-9+\/=]/g,''); + // Remove harmful `=' chars in the middle. + sanitize = sanitize.replace(/=+([A-Za-z0-9+\/])/g, '$1'); + // We need to encode in groups of 4 chars. If we don't have enough, leave the + // excess for later. If there aren't any more, drop enough to make it 4. + let excess = sanitize.length % 4; + if (excess != 0 && more) + buffer = sanitize.slice(-excess); + else + buffer = ''; + sanitize = sanitize.substring(0, sanitize.length - excess); + // Use the atob function we (ought to) have in global scope. + return [atob(sanitize), buffer]; +} + +/** + * Converts a binary string into a Uint8Array buffer. + * + * @param buffer {BinaryString} The string to convert. + * @returns {Uint8Array} The converted data. + */ +function stringToTypedArray(buffer) { + var typedarray = new Uint8Array(buffer.length); + for (var i = 0; i < buffer.length; i++) + typedarray[i] = buffer.charCodeAt(i); + return typedarray; +} + +/** + * Converts a Uint8Array buffer to a binary string. + * + * @param buffer {BinaryString} The string to convert. + * @returns {Uint8Array} The converted data. + */ +function typedArrayToString(buffer) { + var string = ''; + for (var i = 0; i < buffer.length; i+= 100) + string += String.fromCharCode.apply(undefined, buffer.subarray(i, i + 100)); + return string; +} + +/** A list of month names for Date parsing. */ +var kMonthNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", + "Sep", "Oct", "Nov", "Dec"]; + +return { + decode_base64: decode_base64, + decode_qp: decode_qp, + kMonthNames: kMonthNames, + stringToTypedArray: stringToTypedArray, + typedArrayToString: typedArrayToString, +}; +}); +/** + * This file implements knowledge of how to encode or decode structured headers + * for several key headers. It is not meant to be used externally to jsmime. + */ + +def('structuredHeaders', function (require) { +"use strict"; + +var structuredDecoders = new Map(); +var structuredEncoders = new Map(); +var preferredSpellings = new Map(); + +function addHeader(name, decoder, encoder) { + var lowerName = name.toLowerCase(); + structuredDecoders.set(lowerName, decoder); + structuredEncoders.set(lowerName, encoder); + preferredSpellings.set(lowerName, name); +} + + +// Addressing headers: We assume that they can be specified in 1* form (this is +// false for From, but it's close enough to the truth that it shouldn't matter). +// There is no need to specialize the results for the header, so just pun it +// back to parseAddressingHeader. +function parseAddress(value) { + let results = []; + let headerparser = this; + return value.reduce(function (results, header) { + return results.concat(headerparser.parseAddressingHeader(header, true)); + }, []); +} +function writeAddress(value) { + // Make sure the input is an array (accept a single entry) + if (!Array.isArray(value)) + value = [value]; + this.addAddresses(value); +} + +// Addressing headers from RFC 5322: +addHeader("Bcc", parseAddress, writeAddress); +addHeader("Cc", parseAddress, writeAddress); +addHeader("From", parseAddress, writeAddress); +addHeader("Reply-To", parseAddress, writeAddress); +addHeader("Resent-Bcc", parseAddress, writeAddress); +addHeader("Resent-Cc", parseAddress, writeAddress); +addHeader("Resent-From", parseAddress, writeAddress); +addHeader("Resent-Reply-To", parseAddress, writeAddress); +addHeader("Resent-Sender", parseAddress, writeAddress); +addHeader("Resent-To", parseAddress, writeAddress); +addHeader("Sender", parseAddress, writeAddress); +addHeader("To", parseAddress, writeAddress); +// From RFC 5536: +addHeader("Approved", parseAddress, writeAddress); +// From RFC 3798: +addHeader("Disposition-Notification-To", parseAddress, writeAddress); +// Non-standard headers: +addHeader("Delivered-To", parseAddress, writeAddress); +addHeader("Return-Receipt-To", parseAddress, writeAddress); + +// http://cr.yp.to/proto/replyto.html +addHeader("Mail-Reply-To", parseAddress, writeAddress); +addHeader("Mail-Followup-To", parseAddress, writeAddress); + +// Parameter-based headers. Note that all parameters are slightly different, so +// we use slightly different variants here. +function parseParameterHeader(value, do2231, do2047) { + // Only use the first header for parameters; ignore subsequent redefinitions. + return this.parseParameterHeader(value[0], do2231, do2047); +} + +// RFC 2045 +function parseContentType(value) { + let params = parseParameterHeader.call(this, value, false, false); + let origtype = params.preSemi; + let parts = origtype.split('/'); + if (parts.length != 2) { + // Malformed. Return to text/plain. Evil, ain't it? + params = new Map(); + parts = ["text", "plain"]; + } + let mediatype = parts[0].toLowerCase(); + let subtype = parts[1].toLowerCase(); + let type = mediatype + '/' + subtype; + let structure = new Map(); + structure.mediatype = mediatype; + structure.subtype = subtype; + structure.type = type; + params.forEach(function (value, name) { + structure.set(name.toLowerCase(), value); + }); + return structure; +} +structuredDecoders.set("Content-Type", parseContentType); + +// Unstructured headers (just decode RFC 2047 for the first header value) +function parseUnstructured(values) { + return this.decodeRFC2047Words(values[0]); +} +function writeUnstructured(value) { + this.addUnstructured(value); +} + +// Message-ID headers. +function parseMessageID(values) { + // TODO: Proper parsing support for these headers is currently unsupported). + return this.decodeRFC2047Words(values[0]); +} +function writeMessageID(value) { + // TODO: Proper parsing support for these headers is currently unsupported). + this.addUnstructured(value); +} + +// RFC 5322 +addHeader("Comments", parseUnstructured, writeUnstructured); +addHeader("Keywords", parseUnstructured, writeUnstructured); +addHeader("Subject", parseUnstructured, writeUnstructured); + +// RFC 2045 +addHeader("MIME-Version", parseUnstructured, writeUnstructured); +addHeader("Content-Description", parseUnstructured, writeUnstructured); + +// RFC 7231 +addHeader("User-Agent", parseUnstructured, writeUnstructured); + +// Date headers +function parseDate(values) { return this.parseDateHeader(values[0]); } +function writeDate(value) { this.addDate(value); } + +// RFC 5322 +addHeader("Date", parseDate, writeDate); +addHeader("Resent-Date", parseDate, writeDate); +// RFC 5536 +addHeader("Expires", parseDate, writeDate); +addHeader("Injection-Date", parseDate, writeDate); +addHeader("NNTP-Posting-Date", parseDate, writeDate); + +// RFC 5322 +addHeader("Message-ID", parseMessageID, writeMessageID); +addHeader("Resent-Message-ID", parseMessageID, writeMessageID); + +// Miscellaneous headers (those that don't fall under the above schemes): + +// RFC 2047 +structuredDecoders.set("Content-Transfer-Encoding", function (values) { + return values[0].toLowerCase(); +}); +structuredEncoders.set("Content-Transfer-Encoding", writeUnstructured); + +// Some clients like outlook.com send non-compliant References headers that +// separate values using commas. Also, some clients don't separate References +// with spaces, since these are optional according to RFC2822. So here we +// preprocess these headers (see bug 1154521 and bug 1197686). +function preprocessMessageIDs(values) { + let msgId = /<[^>]*>/g; + let match, ids = []; + while ((match = msgId.exec(values)) !== null) { + ids.push(match[0]); + } + return ids.join(' '); +} +structuredDecoders.set("References", preprocessMessageIDs); +structuredDecoders.set("In-Reply-To", preprocessMessageIDs); + +return Object.freeze({ + decoders: structuredDecoders, + encoders: structuredEncoders, + spellings: preferredSpellings, +}); + +}); +def('headerparser', function(require) { +/** + * This file implements the structured decoding of message header fields. It is + * part of the same system as found in mimemimeutils.js, and occasionally makes + * references to globals defined in that file or other dependencies thereof. See + * documentation in that file for more information about external dependencies. + */ + +"use strict"; +var mimeutils = require('./mimeutils'); + +/** + * This is the API that we ultimately return. + * + * We define it as a global here, because we need to pass it as a |this| + * argument to a few functions. + */ +var headerparser = {}; + +/** + * Tokenizes a message header into a stream of tokens as a generator. + * + * The low-level tokens are meant to be loosely correspond to the tokens as + * defined in RFC 5322. For reasons of saner error handling, however, the two + * definitions are not exactly equivalent. The tokens we emit are the following: + * 1. Special delimiters: Any char in the delimiters string is emitted as a + * string by itself. Parsing parameter headers, for example, would use ";=" + * for the delimiter string. + * 2. Quoted-strings (if opt.qstring is true): A string which is surrounded by + * double quotes. Escapes in the string are omitted when returning. + * 3. Domain Literals (if opt.dliteral is true): A string which matches the + * dliteral construct in RFC 5322. Escapes here are NOT omitted. + * 4. Comments (if opt.comments is true): Comments are handled specially. In + * practice, decoding the comments in To headers appears to be necessary, so + * comments are not stripped in the output value. Instead, they are emitted + * as if they are a special delimiter. However, all delimiters found within a + * comment are returned as if they were a quoted string, so that consumers + * ignore delimiters within comments. If ignoring comment text completely is + * desired, upon seeing a "(" token, consumers should ignore all tokens until + * a matching ")" is found (note that comments can be nested). + * 5. RFC 2047 encoded-words (if opts.rfc2047 is true): These are strings which + * are the decoded contents of RFC 2047's =?UTF-8?Q?blah?=-style words. + * 6. Atoms: Atoms are defined not in the RFC 5322 sense, but rather as the + * longest sequence of characters that is neither whitespace nor any of the + * special characters above. + * + * The intended interpretation of the stream of output tokens is that they are + * the portions of text which can be safely wrapped in whitespace with no ill + * effect. The output tokens are either strings (which represent individual + * delimiter tokens) or instances of a class that has a customized .toString() + * for output (for quoted strings, atoms, domain literals, and encoded-words). + * Checking for a delimiter MUST use the strictly equals operator (===). For + * example, the proper way to call this method is as follows: + * + * for (let token of getHeaderTokens(rest, ";=", opts)) { + * if (token === ';') { + * // This represents a literal ';' in the string + * } else if (token === '=') { + * // This represents a literal '=' in the string + * } else { + * // If a ";" qstring was parsed, we fall through to here! + * token = token.toString(); + * } + * } + * + * This method does not properly tokenize 5322 in all corner cases; however, + * this is equivalent in those corner cases to an older header parsing + * algorithm, so the algorithm should be correct for all real-world cases. The + * corner cases are as follows: + * 1. Quoted-strings and domain literals are parsed even if they are within a + * comment block (we effectively treat ctext as containing qstring). + * 2. WSP need not be between a qstring and an atom (a"b" produces two tokens, + * a and b). This is an error case, though. + * 3. Legacy comments as display names: We recognize address fields with + * comments, and (a) either drop them if inside addr-spec or (b) preserve + * them as part of the display-name if not. If the display-name is empty + * while the last comment is not, we assume it's the legacy form above and + * take the comment content as the display-name. + * + * @param {String} value The header value, post charset conversion but + * before RFC 2047 decoding, to be parsed. + * @param {String} delimiters A set of delimiters to include as individual + * tokens. + * @param {Object} opts A set of options selecting what to parse. + * @param {Boolean} [opts.qstring] If true, recognize quoted strings. + * @param {Boolean} [opts.dliteral] If true, recognize domain literals. + * @param {Boolean} [opts.comments] If true, recognize comments. + * @param {Boolean} [opts.rfc2047] If true, parse and decode RFC 2047 + * encoded-words. + * @returns {(Token|String)[]} An array of Token objects (which have a toString + * method returning their value) or String objects + * (representing delimiters). + */ +function getHeaderTokens(value, delimiters, opts) { + // The array of parsed tokens. This method used to be a generator, but it + // appears that generators are poorly optimized in current engines, so it was + // converted to not be one. + let tokenList = []; + + /// Represents a non-delimiter token + function Token(token) { + // Unescape all quoted pairs. Any trailing \ is deleted. + this.token = token.replace(/\\(.?)/g, "$1"); + } + Token.prototype.toString = function () { return this.token; }; + + // The start of the current token (e.g., atoms, strings) + let tokenStart = undefined; + // The set of whitespace characters, as defined by RFC 5322 + let wsp = " \t\r\n"; + // If we are a domain literal ([]) or a quoted string ("), this is set to the + // character to look for at the end. + let endQuote = undefined; + // The current depth of comments, since they can be nested. A value 0 means we + // are not in a comment. + let commentDepth = 0; + + // Iterate over every character one character at a time. + let length = value.length; + for (let i = 0; i < length; i++) { + let ch = value[i]; + // If we see a \, no matter what context we are in, ignore the next + // character. + if (ch == '\\') { + i++; + continue; + } + + // If we are in a qstring or a dliteral, process the character only if it is + // what we are looking for to end the quote. + if (endQuote !== undefined) { + if (ch == endQuote && ch == '"') { + // Quoted strings don't include their delimiters. + let text = value.slice(tokenStart + 1, i); + + // If RFC 2047 is enabled, always decode the qstring. + if (opts.rfc2047) + text = decodeRFC2047Words(text); + + tokenList.push(new Token(text)); + endQuote = undefined; + tokenStart = undefined; + } else if (ch == endQuote && ch == ']') { + // Domain literals include their delimiters. + tokenList.push(new Token(value.slice(tokenStart, i + 1))); + endQuote = undefined; + tokenStart = undefined; + } + // Avoid any further processing. + continue; + } + + // If we can match the RFC 2047 encoded-word pattern, we need to decode the + // entire word or set of words. + if (opts.rfc2047 && ch == '=' && i + 1 < value.length && value[i + 1] == '?') { + // RFC 2047 tokens separated only by whitespace are conceptually part of + // the same output token, so we need to decode them all at once. + let encodedWordsRE = /([ \t\r\n]*=\?[^?]*\?[BbQq]\?[^?]*\?=)+/; + let result = encodedWordsRE.exec(value.slice(i)); + if (result !== null) { + // If we were in the middle of a prior token (i.e., something like + // foobar=?UTF-8?Q?blah?=), yield the previous segment as a token. + if (tokenStart !== undefined) { + tokenList.push(new Token(value.slice(tokenStart, i))); + tokenStart = undefined; + } + + // Find out how much we need to decode... + let encWordsLen = result[0].length; + let string = decodeRFC2047Words(value.slice(i, i + encWordsLen), + "UTF-8"); + // Don't make a new Token variable, since we do not want to unescape the + // decoded string. + tokenList.push({ toString: function() { return string; }}); + + // Skip everything we decoded. The -1 is because we don't want to + // include the starting character. + i += encWordsLen - 1; + continue; + } + + // If we are here, then we failed to match the simple 2047 encoded-word + // regular expression, despite the fact that it matched the =? at the + // beginning. Fall through and treat the text as if we aren't trying to + // decode RFC 2047. + } + + // If we reach this point, we're not inside of quoted strings, domain + // literals, or RFC 2047 encoded-words. This means that the characters we + // parse are potential delimiters (unless we're in comments, where + // everything starts to go really wonky). Several things could happen, + // depending on the kind of character we read and whether or not we were in + // the middle of a token. The three values here tell us what we could need + // to do at this point: + // tokenIsEnding: The current character is not able to be accumulated to an + // atom, so we need to flush the atom if there is one. + // tokenIsStarting: The current character could begin an atom (or + // anything that requires us to mark the starting point), so we need to save + // the location. + // isSpecial: The current character is a delimiter that needs to be output. + let tokenIsEnding = false, tokenIsStarting = false, isSpecial = false; + if (wsp.includes(ch)) { + // Whitespace ends current tokens, doesn't emit anything. + tokenIsEnding = true; + } else if (commentDepth == 0 && delimiters.includes(ch)) { + // Delimiters end the current token, and need to be output. They do not + // apply within comments. + tokenIsEnding = true; + isSpecial = true; + } else if (opts.qstring && ch == '"') { + // Quoted strings end the last token and start a new one. + tokenIsEnding = true; + tokenIsStarting = true; + endQuote = ch; + } else if (opts.dliteral && ch == '[') { + // Domain literals end the last token and start a new one. + tokenIsEnding = true; + tokenIsStarting = true; + endQuote = ']'; + } else if (opts.comments && ch == '(') { + // Comments are nested (oh joy). We only really care for the outer + // delimiter, though, which also ends the prior token and needs to be + // output if the consumer requests it. + commentDepth++; + if (commentDepth == 1) { + tokenIsEnding = true; + isSpecial = true; + } else { + tokenIsStarting = true; + } + } else if (opts.comments && ch == ')') { + // Comments are nested (oh joy). We only really care for the outer + // delimiter, though, which also ends the prior token and needs to be + // output if the consumer requests it. + if (commentDepth > 0) + commentDepth--; + if (commentDepth == 0) { + tokenIsEnding = true; + isSpecial = true; + } else { + tokenIsStarting = true; + } + } else { + // Not a delimiter, whitespace, comment, domain literal, or quoted string. + // Must be part of an atom then! + tokenIsStarting = true; + } + + // If our analysis concluded that we closed an open token, and there is an + // open token, then yield that token. + if (tokenIsEnding && tokenStart !== undefined) { + tokenList.push(new Token(value.slice(tokenStart, i))); + tokenStart = undefined; + } + // If we need to output a delimiter, do so. + if (isSpecial) + tokenList.push(ch); + // If our analysis concluded that we could open a token, and no token is + // opened yet, then start the token. + if (tokenIsStarting && tokenStart === undefined) { + tokenStart = i; + } + } + + // That concludes the loop! If there is a currently open token, close that + // token now. + if (tokenStart !== undefined) { + // Error case: a partially-open quoted string is assumed to have a trailing + // " character. + if (endQuote == '"') + tokenList.push(new Token(value.slice(tokenStart + 1))); + else + tokenList.push(new Token(value.slice(tokenStart))); + } + + return tokenList; +} + +/** + * Convert a header value into UTF-16 strings by attempting to decode as UTF-8 + * or another legacy charset. If the header is valid UTF-8, it will be decoded + * as UTF-8; if it is not, the fallbackCharset will be attempted instead. + * + * @param {String} headerValue The header (as a binary string) to attempt + * to convert to UTF-16. + * @param {String} [fallbackCharset] The optional charset to try if UTF-8 + * doesn't work. + * @returns {String} The UTF-16 representation of the string above. + */ +function convert8BitHeader(headerValue, fallbackCharset) { + // Only attempt to convert the headerValue if it contains non-ASCII + // characters. + if (/[\x80-\xff]/.exec(headerValue)) { + // First convert the value to a typed-array for TextDecoder. + let typedarray = mimeutils.stringToTypedArray(headerValue); + + // Don't try UTF-8 as fallback (redundant), and don't try UTF-16 or UTF-32 + // either, since they radically change header interpretation. + // If we have a fallback charset, we want to know if decoding will fail; + // otherwise, we want to replace with substitution chars. + let hasFallback = fallbackCharset && + !fallbackCharset.toLowerCase().startsWith("utf"); + let utf8Decoder = new TextDecoder("utf-8", {fatal: hasFallback}); + try { + headerValue = utf8Decoder.decode(typedarray); + } catch (e) { + // Failed, try the fallback + let decoder = new TextDecoder(fallbackCharset, {fatal: false}); + headerValue = decoder.decode(typedarray); + } + } + return headerValue; +} + +/** + * Decodes all RFC 2047 encoded-words in the input string. The string does not + * necessarily have to contain any such words. This is useful, for example, for + * parsing unstructured headers. + * + * @param {String} headerValue The header which may contain RFC 2047 encoded- + * words. + * @returns {String} A full UTF-16 string with all encoded words expanded. + */ +function decodeRFC2047Words(headerValue) { + // Unfortunately, many implementations of RFC 2047 encoding are actually wrong + // in that they split over-long encoded words without regard for whether or + // not the split point is in the middle of a multibyte character. Therefore, + // we need to be able to handle these situations gracefully. This is done by + // using the decoder in streaming mode so long as the next token is another + // 2047 token with the same charset. + let lastCharset = '', currentDecoder = undefined; + + /** + * Decode a single RFC 2047 token. This function is inline so that we can + * easily close over the lastCharset/currentDecoder variables, needed for + * handling bad RFC 2047 productions properly. + */ + function decode2047Token(token, isLastToken) { + let tokenParts = token.split("?"); + + // If it's obviously not a valid token, return false immediately. + if (tokenParts.length != 5 || tokenParts[4] != '=') + return false; + + // The charset parameter is defined in RFC 2231 to be charset or + // charset*language. We only care about the charset here, so ignore any + // language parameter that gets passed in. + let charset = tokenParts[1].split('*', 1)[0]; + let encoding = tokenParts[2], text = tokenParts[3]; + + let buffer; + if (encoding == 'B' || encoding == 'b') { + // Decode base64. If there's any non-base64 data, treat the string as + // an illegal token. + if (/[^A-Za-z0-9+\/=]/.exec(text)) + return false; + + // Decode the string + buffer = mimeutils.decode_base64(text, false)[0]; + } else if (encoding == 'Q' || encoding == 'q') { + // Q encoding here looks a lot like quoted-printable text. The differences + // between quoted-printable and this are that quoted-printable allows you + // to quote newlines (this doesn't), while this replaces spaces with _. + // We can reuse the decode_qp code here, since newlines are already + // stripped from the header. There is one edge case that could trigger a + // false positive, namely when you have a single = or an = followed by + // whitespace at the end of the string. Such an input string is already + // malformed to begin with, so stripping the = and following input in that + // case should not be an important loss. + buffer = mimeutils.decode_qp(text.replace(/_/g, ' '), false)[0]; + } else { + return false; + } + + // Make the buffer be a typed array for what follows + let stringBuffer = buffer; + buffer = mimeutils.stringToTypedArray(buffer); + + // If we cannot reuse the last decoder, flush out whatever remains. + var output = ''; + if (charset != lastCharset && currentDecoder) { + output += currentDecoder.decode(); + currentDecoder = null; + } + + // Initialize the decoder for this token. + lastCharset = charset; + if (!currentDecoder) { + try { + currentDecoder = new TextDecoder(charset, {fatal: false}); + } catch (e) { + // We don't recognize the charset, so give up. + return false; + } + } + + // Convert this token with the buffer. Note the stream parameter--although + // RFC 2047 tokens aren't supposed to break in the middle of a multibyte + // character, a lot of software messes up and does so because it's hard not + // to (see headeremitter.js for exactly how hard!). + // We must not stream ISO-2022-JP if the buffer switches back to + // the ASCII state, that is, ends in "ESC(B". + // Also, we shouldn't do streaming on the last token. + let doStreaming; + if (isLastToken || + (charset.toUpperCase() == "ISO-2022-JP" && + stringBuffer.endsWith("\x1B(B"))) + doStreaming = {stream: false}; + else + doStreaming = {stream: true}; + return output + currentDecoder.decode(buffer, doStreaming); + } + + // The first step of decoding is to split the string into RFC 2047 and + // non-RFC 2047 tokens. RFC 2047 tokens look like the following: + // =?charset?c?text?=, where c is one of B, b, Q, and q. The split regex does + // some amount of semantic checking, so that malformed RFC 2047 tokens will + // get ignored earlier. + let components = headerValue.split(/(=\?[^?]*\?[BQbq]\?[^?]*\?=)/); + + // Find last RFC 2047 token. + let lastRFC2047Index = -1; + for (let i = 0; i < components.length; i++) { + if (components[i].substring(0, 2) == "=?") + lastRFC2047Index = i; + } + for (let i = 0; i < components.length; i++) { + if (components[i].substring(0, 2) == "=?") { + let decoded = decode2047Token(components[i], i == lastRFC2047Index); + if (decoded !== false) { + // If 2047 decoding succeeded for this bit, rewrite the original value + // with the proper decoding. + components[i] = decoded; + + // We're done processing, so continue to the next link. + continue; + } + } else if (/^[ \t\r\n]*$/.exec(components[i])) { + // Whitespace-only tokens get squashed into nothing, so 2047 tokens will + // be concatenated together. + components[i] = ''; + continue; + } + + // If there was stuff left over from decoding the last 2047 token, flush it + // out. + lastCharset = ''; + if (currentDecoder) { + components[i] = currentDecoder.decode() + components[i]; + currentDecoder = null; + } + } + + // After the for loop, we'll have a set of decoded strings. Concatenate them + // together to make the return value. + return components.join(''); +} + +/////////////////////////////// +// Structured field decoders // +/////////////////////////////// + +/** + * Extract a list of addresses from a header which matches the RFC 5322 + * address-list production, possibly doing RFC 2047 decoding along the way. + * + * The output of this method is an array of elements corresponding to the + * addresses and the groups in the input header. An address is represented by + * an object of the form: + * { + * name: The display name of the address + * email: The address of the object + * } + * while a group is represented by an object of the form: + * { + * name: The display name of the group + * group: An array of address object for members in the group. + * } + * + * @param {String} header The MIME header text to be parsed + * @param {Boolean} doRFC2047 If true, decode RFC 2047 parameters found in the + * header. + * @returns {(Address|Group)[]} An array of the addresses found in the header, + * where each element is of the form mentioned + * above. + */ +function parseAddressingHeader(header, doRFC2047) { + // Default to true + if (doRFC2047 === undefined) + doRFC2047 = true; + + // The final (top-level) results list to append to. + let results = []; + // Temporary results + let addrlist = []; + + // Build up all of the values + let name = '', groupName = '', localPart = '', address = '', comment = ''; + // Indicators of current state + let inAngle = false, inComment = false, needsSpace = false; + let preserveSpace = false; + let commentClosed = false; + + // RFC 5322 §3.4 notes that legacy implementations exist which use a simple + // recipient form where the addr-spec appears without the angle brackets, + // but includes the name of the recipient in parentheses as a comment + // following the addr-spec. While we do not create this format, we still + // want to recognize it, though. + // Furthermore, despite allowing comments in addresses, RFC 5322 §3.4 notes + // that legacy implementations may interpret the comment, and thus it + // recommends not to use them. (Also, they may be illegal as per RFC 5321.) + // While we do not create address fields with comments, we recognize such + // comments during parsing and (a) either drop them if inside addr-spec or + // (b) preserve them as part of the display-name if not. + // If the display-name is empty while the last comment is not, we assume it's + // the legacy form above and take the comment content as the display-name. + // + // When parsing the address field, we at first do not know whether any + // strings belong to the display-name (which may include comments) or to the + // local-part of an addr-spec (where we ignore comments) until we find an + // '@' or an '<' token. Thus, we collect both variants until the fog lifts, + // plus the last comment seen. + let lastComment = ''; + + /** + * Add the parsed mailbox object to the address list. + * If it's in the legacy form above, correct the display-name. + * Also reset any faked flags. + * @param {String} displayName display-name as per RFC 5322 + * @param {String} addrSpec addr-spec as per RFC 5322 + */ + function addToAddrList(displayName, addrSpec) { + // Keep the local-part quoted if it needs to be. + let lp = addrSpec.substring(0, addrSpec.lastIndexOf("@")); + if (/[ !()<>\[\]:;@\\,"]/.exec(lp) !== null) { + addrSpec = '"' + lp.replace(/([\\"])/g, "\\$1") + '"' + + addrSpec.substring(addrSpec.lastIndexOf("@")); + } + + if (displayName === '' && lastComment !== '') { + // Take last comment content as the display-name. + let offset = lastComment[0] === ' ' ? 2 : 1; + displayName = lastComment.substr(offset, lastComment.length - offset - 1); + } + if (displayName !== '' || addrSpec !== '') + addrlist.push({name: displayName, email: addrSpec}); + // Clear pending flags and variables. + name = localPart = address = lastComment = ''; + inAngle = inComment = needsSpace = false; + } + + // Main parsing loop + for (let token of getHeaderTokens(header, ":,;<>@", + {qstring: true, comments: true, dliteral: true, rfc2047: doRFC2047})) { + if (token === ':') { + groupName = name; + name = ''; + localPart = ''; + // If we had prior email address results, commit them to the top-level. + if (addrlist.length > 0) + results = results.concat(addrlist); + addrlist = []; + } else if (token === '<') { + if (inAngle) { + // Interpret the address we were parsing as a name. + if (address.length > 0) { + name = address; + } + localPart = address = ''; + } else { + inAngle = true; + } + } else if (token === '>') { + inAngle = false; + // Forget addr-spec comments. + lastComment = ''; + } else if (token === '(') { + inComment = true; + // The needsSpace flag may not always be set even if it should be, + // e.g. for a comment behind an angle-addr. + // Also, we need to restore the needsSpace flag if we ignore the comment. + preserveSpace = needsSpace; + if (!needsSpace) + needsSpace = name !== '' && name.substr(-1) !== ' '; + comment = needsSpace ? ' (' : '('; + commentClosed = false; + } else if (token === ')') { + inComment = false; + comment += ')'; + lastComment = comment; + // The comment may be part of the name, but not of the local-part. + // Enforce a space behind the comment only when not ignoring it. + if (inAngle) { + needsSpace = preserveSpace; + } else { + name += comment; + needsSpace = true; + } + commentClosed = true; + continue; + } else if (token === '@') { + // An @ means we see an email address. If we're not within <> brackets, + // then we just parsed an email address instead of a display name. Empty + // out the display name for the current production. + if (!inAngle) { + address = localPart; + name = ''; + localPart = ''; + // The remainder of this mailbox is part of an addr-spec. + inAngle = true; + } + address += '@'; + } else if (token === ',') { + // A comma ends the current name. If we have something that's kind of a + // name, add it to the result list. If we don't, then our input looks like + // To: , , -> don't bother adding an empty entry. + addToAddrList(name, address); + } else if (token === ';') { + // Add pending name to the list + addToAddrList(name, address); + + // If no group name was found, treat the ';' as a ','. In any case, we + // need to copy the results of addrlist into either a new group object or + // the main list. + if (groupName === '') { + results = results.concat(addrlist); + } else { + results.push({ + name: groupName, + group: addrlist + }); + } + // ... and reset every other variable. + addrlist = []; + groupName = ''; + } else { + // This is either comment content, a quoted-string, or some span of + // dots and atoms. + + // Ignore the needs space if we're a "close" delimiter token. + let spacedToken = token; + if (needsSpace && token.toString()[0] != '.') + spacedToken = ' ' + spacedToken; + + // Which field do we add this data to? + if (inComment) { + comment += spacedToken; + } else if (inAngle) { + address += spacedToken; + } else { + name += spacedToken; + // Never add a space to the local-part, if we just ignored a comment. + if (commentClosed) { + localPart += token; + commentClosed = false; + } else { + localPart += spacedToken; + } + } + + // We need space for the next token if we aren't some kind of comment or + // . delimiter. + needsSpace = token.toString()[0] != '.'; + // The fall-through case after this resets needsSpace to false, and we + // don't want that! + continue; + } + + // If we just parsed a delimiter, we don't need any space for the next + // token. + needsSpace = false; + } + + // If we're missing the final ';' of a group, assume it was present. Also, add + // in the details of any email/address that we previously saw. + addToAddrList(name, address); + if (groupName !== '') { + results.push({name: groupName, group: addrlist}); + addrlist = []; + } + + // Add the current address list build-up to the list of addresses, and return + // the whole array to the caller. + return results.concat(addrlist); +} + +/** + * Extract parameters from a header which is a series of ;-separated + * attribute=value tokens. + * + * @param {String} headerValue The MIME header value to parse. + * @param {Boolean} doRFC2047 If true, decode RFC 2047 encoded-words. + * @param {Boolean} doRFC2231 If true, decode RFC 2231 encoded parameters. + * @return {Map(String -> String)} A map of parameter names to parameter values. + * The property preSemi is set to the token that + * precedes the first semicolon. + */ +function parseParameterHeader(headerValue, doRFC2047, doRFC2231) { + // The basic syntax of headerValue is token [; token = token-or-qstring]* + // Copying more or less liberally from nsMIMEHeaderParamImpl: + // The first token is the text to the first whitespace or semicolon. + var semi = headerValue.indexOf(";"); + if (semi < 0) { + var start = headerValue; + var rest = ''; + } else { + var start = headerValue.substring(0, semi); + var rest = headerValue.substring(semi); // Include the semicolon + } + // Strip start to be <WSP><nowsp><WSP>. + start = start.trim().split(/[ \t\r\n]/)[0]; + + // Decode the the parameter tokens. + let opts = {qstring: true, rfc2047: doRFC2047}; + // Name is the name of the parameter, inName is true iff we don't have a name + // yet. + let name = '', inName = true; + // Matches is a list of [name, value] pairs, where we found something that + // looks like name=value in the input string. + let matches = []; + for (let token of getHeaderTokens(rest, ";=", opts)) { + if (token === ';') { + // If we didn't find a name yet (we have ... tokenA; tokenB), push the + // name with an empty token instead. + if (name != '' && inName == false) + matches.push([name, '']); + name = ''; + inName = true; + } else if (token === '=') { + inName = false; + } else if (inName && name == '') { + name = token.toString(); + } else if (!inName && name != '') { + token = token.toString(); + // RFC 2231 doesn't make it clear if %-encoding is supposed to happen + // within a quoted string, but this is very much required in practice. If + // it ends with a '*', then the string is an extended-value, which means + // that its value may be %-encoded. + if (doRFC2231 && name.endsWith('*')) { + token = token.replace(/%([0-9A-Fa-f]{2})/g, + function percent_deencode(match, hexchars) { + return String.fromCharCode(parseInt(hexchars, 16)); + }); + } + matches.push([name, token]); + // Clear the name, so we ignore anything afterwards. + name = ''; + } else if (inName) { + // We have ...; tokenA tokenB ... -> ignore both tokens + name = ''; // Error recovery, ignore this one + } + } + // If we have a leftover ...; tokenA, push the tokenA + if (name != '' && inName == false) + matches.push([name, '']); + + // Now matches holds the parameters, so clean up for RFC 2231. There are three + // cases: param=val, param*=us-ascii'en-US'blah, and param*n= variants. The + // order of preference is to pick the middle, then the last, then the first. + // Note that we already unpacked %-encoded values. + + // simpleValues is just a straight parameter -> value map. + // charsetValues is the parameter -> value map, although values are stored + // before charset decoding happens. + // continuationValues maps parameter -> array of values, with extra properties + // valid (if we decided we couldn't do anything anymore) and hasCharset (which + // records if we need to decode the charset parameter or not). + var simpleValues = new Map(), charsetValues = new Map(), + continuationValues = new Map(); + for (let pair of matches) { + let name = pair[0]; + let value = pair[1]; + // Get first index, not last index, so we match param*0*= like param*0=. + let star = name.indexOf('*'); + if (star == -1) { + // This is the case of param=val. Select the first value here, if there + // are multiple ones. + if (!simpleValues.has(name)) + simpleValues.set(name, value); + } else if (star == name.length - 1) { + // This is the case of param*=us-ascii'en-US'blah. + name = name.substring(0, star); + // Again, select only the first value here. + if (!charsetValues.has(name)) + charsetValues.set(name, value); + } else { + // This is the case of param*0= or param*0*=. + let param = name.substring(0, star); + let entry = continuationValues.get(param); + // Did we previously find this one to be bungled? Then ignore it. + if (continuationValues.has(param) && !entry.valid) + continue; + + // If we haven't seen it yet, set up entry already. Note that entries are + // not straight string values but rather [valid, hasCharset, param0, ... ] + if (!continuationValues.has(param)) { + entry = new Array(); + entry.valid = true; + entry.hasCharset = undefined; + continuationValues.set(param, entry); + } + + // When the string ends in *, we need to charset decoding. + // Note that the star is only meaningful for the *0*= case. + let lastStar = name[name.length - 1] == '*'; + let number = name.substring(star + 1, name.length - (lastStar ? 1 : 0)); + if (number == '0') + entry.hasCharset = lastStar; + + // Is the continuation number illegal? + else if ((number[0] == '0' && number != '0') || + !(/^[0-9]+$/.test(number))) { + entry.valid = false; + continue; + } + // Normalize to an integer + number = parseInt(number, 10); + + // Is this a repeat? If so, bail. + if (entry[number] !== undefined) { + entry.valid = false; + continue; + } + + // Set the value for this continuation index. JS's magic array setter will + // expand the array if necessary. + entry[number] = value; + } + } + + // Build the actual parameter array from the parsed values + var values = new Map(); + // Simple values have lowest priority, so just add everything into the result + // now. + for (let pair of simpleValues) { + values.set(pair[0], pair[1]); + } + + if (doRFC2231) { + // Continuation values come next + for (let pair of continuationValues) { + let name = pair[0]; + let entry = pair[1]; + // If we never saw a param*0= or param*0*= value, then we can't do any + // reasoning about what it looks like, so bail out now. + if (entry.hasCharset === undefined) continue; + + // Use as many entries in the array as are valid--if we are missing an + // entry, stop there. + let valid = true; + for (var i = 0; valid && i < entry.length; i++) + if (entry[i] === undefined) + valid = false; + + // Concatenate as many parameters as are valid. If we need to decode thec + // charset, do so now. + var value = entry.slice(0, i).join(''); + if (entry.hasCharset) { + try { + value = decode2231Value(value); + } catch (e) { + // Bad charset, don't add anything. + continue; + } + } + // Finally, add this to the output array. + values.set(name, value); + } + + // Highest priority is the charset conversion. + for (let pair of charsetValues) { + try { + values.set(pair[0], decode2231Value(pair[1])); + } catch (e) { + // Bad charset, don't add anything. + } + } + } + + // Finally, return the values computed above. + values.preSemi = start; + return values; +} + +/** + * Convert a RFC 2231-encoded string parameter into a Unicode version of the + * string. This assumes that percent-decoding has already been applied. + * + * @param {String} value The RFC 2231-encoded string to decode. + * @return The Unicode version of the string. + */ +function decode2231Value(value) { + let quote1 = value.indexOf("'"); + let quote2 = quote1 >= 0 ? value.indexOf("'", quote1 + 1) : -1; + + let charset = (quote1 >= 0 ? value.substring(0, quote1) : ""); + // It turns out that the language isn't useful anywhere in our codebase for + // the present time, so we will safely ignore it. + //var language = (quote2 >= 0 ? value.substring(quote1 + 2, quote2) : ""); + value = value.substring(Math.max(quote1, quote2) + 1); + + // Convert the value into a typed array for decoding + let typedarray = mimeutils.stringToTypedArray(value); + + // Decode the charset. If the charset isn't found, we throw an error. Try to + // fallback in that case. + return new TextDecoder(charset, {fatal: true}) + .decode(typedarray, {stream: false}); +} + +// This is a map of known timezone abbreviations, for fallback in obsolete Date +// productions. +var kKnownTZs = { + // The following timezones are explicitly listed in RFC 5322. + "UT": "+0000", "GMT": "+0000", + "EST": "-0500", "EDT": "-0400", + "CST": "-0600", "CDT": "-0500", + "MST": "-0700", "MDT": "-0600", + "PST": "-0800", "PDT": "-0700", + // The following are time zones copied from NSPR's prtime.c + "AST": "-0400", // Atlantic Standard Time + "NST": "-0330", // Newfoundland Standard Time + "BST": "+0100", // British Summer Time + "MET": "+0100", // Middle Europe Time + "EET": "+0200", // Eastern Europe Time + "JST": "+0900" // Japan Standard Time +}; + +/** + * Parse a header that contains a date-time definition according to RFC 5322. + * The result is a JS date object with the same timestamp as the header. + * + * The dates returned by this parser cannot be reliably converted back into the + * original header for two reasons. First, JS date objects cannot retain the + * timezone information they were initialized with, so reserializing a date + * header would necessarily produce a date in either the current timezone or in + * UTC. Second, JS dates measure time as seconds elapsed from the POSIX epoch + * excluding leap seconds. Any timestamp containing a leap second is instead + * converted into one that represents the next second. + * + * Dates that do not match the RFC 5322 production are instead attempted to + * parse using the Date.parse function. The strings that are accepted by + * Date.parse are not fully defined by the standard, but most implementations + * should accept strings that look rather close to RFC 5322 strings. Truly + * invalid dates produce a formulation that results in an invalid date, + * detectable by having its .getTime() method return NaN. + * + * @param {String} header The MIME header value to parse. + * @returns {Date} The date contained within the header, as described + * above. + */ +function parseDateHeader(header) { + let tokens = getHeaderTokens(header, ",:", {}).map(x => x.toString()); + // What does a Date header look like? In practice, most date headers devolve + // into Date: [dow ,] dom mon year hh:mm:ss tzoff [(abbrev)], with the day of + // week mostly present and the timezone abbreviation mostly absent. + + // First, ignore the day-of-the-week if present. This would be the first two + // tokens. + if (tokens.length > 1 && tokens[1] === ',') + tokens = tokens.slice(2); + + // If there are too few tokens, the date is obviously invalid. + if (tokens.length < 8) + return new Date(NaN); + + // Save off the numeric tokens + let day = parseInt(tokens[0]); + // month is tokens[1] + let year = parseInt(tokens[2]); + let hours = parseInt(tokens[3]); + // tokens[4] === ':' + let minutes = parseInt(tokens[5]); + // tokens[6] === ':' + let seconds = parseInt(tokens[7]); + + // Compute the month. Check only the first three digits for equality; this + // allows us to accept, e.g., "January" in lieu of "Jan." + let month = mimeutils.kMonthNames.indexOf(tokens[1].slice(0, 3)); + // If the month name is not recognized, make the result illegal. + if (month < 0) + month = NaN; + + // Compute the full year if it's only 2 digits. RFC 5322 states that the + // cutoff is 50 instead of 70. + if (year < 100) { + year += year < 50 ? 2000 : 1900; + } + + // Compute the timezone offset. If it's not in the form ±hhmm, convert it to + // that form. + let tzoffset = tokens[8]; + if (tzoffset in kKnownTZs) + tzoffset = kKnownTZs[tzoffset]; + let decompose = /^([+-])(\d\d)(\d\d)$/.exec(tzoffset); + // Unknown? Make it +0000 + if (decompose === null) + decompose = ['+0000', '+', '00', '00']; + let tzOffsetInMin = parseInt(decompose[2]) * 60 + parseInt(decompose[3]); + if (decompose[1] == '-') + tzOffsetInMin = -tzOffsetInMin; + + // How do we make the date at this point? Well, the JS date's constructor + // builds the time in terms of the local timezone. To account for the offset + // properly, we need to build in UTC. + let finalDate = new Date(Date.UTC(year, month, day, hours, minutes, seconds) + - tzOffsetInMin * 60 * 1000); + + // Suppose our header was mangled and we couldn't read it--some of the fields + // became undefined. In that case, the date would become invalid, and the + // indication that it is so is that the underlying number is a NaN. In that + // scenario, we could build attempt to use JS Date parsing as a last-ditch + // attempt. But it's not clear that such messages really exist in practice, + // and the valid formats for Date in ES6 are unspecified. + return finalDate; +} + +//////////////////////////////////////// +// Structured header decoding support // +//////////////////////////////////////// + +// Load the default structured decoders +var structuredDecoders = new Map(); +var structuredHeaders = require('./structuredHeaders'); +var preferredSpellings = structuredHeaders.spellings; +var forbiddenHeaders = new Set(); +for (let pair of structuredHeaders.decoders) { + addStructuredDecoder(pair[0], pair[1]); + forbiddenHeaders.add(pair[0].toLowerCase()); +} + +/** + * Use an already-registered structured decoder to parse the value of the header + * into a structured representation. + * + * As this method is designed to be used for the internal MIME Parser to convert + * the raw header values to well-structured values, value is intended to be an + * array consisting of all occurences of the header in order. However, for ease + * of use by other callers, it can also be treated as a string. + * + * If the decoder for the header is not found, an exception will be thrown. + * + * A large set of headers have pre-defined structured decoders; these decoders + * cannot be overrided with addStructuredDecoder, as doing so could prevent the + * MIME or message parsers from working properly. The pre-defined structured + * headers break down into five clases of results, plus some ad-hoc + * representations. They are: + * + * Addressing headers (results are the same as parseAddressingHeader): + * - Approved + * - Bcc + * - Cc + * - Delivered-To + * - Disposition-Notification-To + * - From + * - Mail-Reply-To + * - Mail-Followup-To + * - Reply-To + * - Resent-Bcc + * - Resent-Cc + * - Resent-From + * - Resent-Reply-To + * - Resent-Sender + * - Resent-To + * - Return-Receipt-To + * - Sender + * - To + * + * Date headers (results are the same as parseDateHeader): + * - Date + * - Expires + * - Injection-Date + * - NNTP-Posting-Date + * - Resent-Date + * + * References headers (results are the same as parseReferencesHeader): + * - (TODO: Parsing support for these headers is currently unsupported) + * + * Message-ID headers (results are the first entry of the result of + * parseReferencesHeader): + * - (TODO: Parsing support for these headers is currently unsupported) + * + * Unstructured headers (results are merely decoded according to RFC 2047): + * - Comments + * - Content-Description + * - Keywords + * - Subject + * + * The ad-hoc headers and their resulting formats are as follows: + * Content-Type: returns a JS Map of parameter names (in lower case) to their + * values, along with the following extra properties defined on the map: + * - mediatype: the type to the left of '/' (e.g., 'text', 'message') + * - subtype: the type to the right of '/' (e.g., 'plain', 'rfc822') + * - type: the full typename (e.g., 'text/plain') + * RFC 2047 and RFC 2231 decoding is applied where appropriate. The values of + * the type, mediatype, and subtype attributes are all normalized to lower-case, + * as are the names of all parameters. + * + * Content-Transfer-Encoding: the first value is converted to lower-case. + * + * @param {String} header The name of the header of the values. + * @param {String|Array} value The value(s) of the headers, after charset + * conversion (if any) has been applied. If it is + * an array, the headers are listed in the order + * they appear in the message. + * @returns {Object} A structured representation of the header values. + */ +function parseStructuredHeader(header, value) { + // Enforce that the parameter is an array. If it's a string, make it a + // 1-element array. + if (typeof value === "string" || value instanceof String) + value = [value]; + if (!Array.isArray(value)) + throw new TypeError("Header value is not an array: " + value); + + // Lookup the header in our decoders; if present, use that to decode the + // header. + let lowerHeader = header.toLowerCase(); + if (structuredDecoders.has(lowerHeader)) { + return structuredDecoders.get(lowerHeader).call(headerparser, value); + } + + // If not present, throw an exception. + throw new Error("Unknown structured header: " + header); +} + +/** + * Add a custom structured MIME decoder to the set of known decoders. These + * decoders are used for {@link parseStructuredHeader} and similar functions to + * encode richer, more structured values instead of relying on string + * representations everywhere. + * + * Structured decoders are functions which take in a single parameter consisting + * of an array of the string values of the header, in order that they appear in + * the message. These headers have had the charset conversion (if necessary) + * applied to them already. The this parameter of the function is set to be the + * jsmime.headerparser module. + * + * There is a large set of structured decoders built-in to the jsmime library + * already. As these headers are fundamental to the workings of jsmime, + * attempting to replace them with a custom version will instead produce an + * exception. + * + * @param {String} header The header name (in any case) + * for which the decoder will be + * used. + * @param {Function(String[] -> Object)} decoder The structured decoder + * function. + */ +function addStructuredDecoder(header, decoder) { + let lowerHeader = header.toLowerCase(); + if (forbiddenHeaders.has(lowerHeader)) + throw new Error("Cannot override header: " + header); + structuredDecoders.set(lowerHeader, decoder); + if (!preferredSpellings.has(lowerHeader)) + preferredSpellings.set(lowerHeader, header); +} + +headerparser.addStructuredDecoder = addStructuredDecoder; +headerparser.convert8BitHeader = convert8BitHeader; +headerparser.decodeRFC2047Words = decodeRFC2047Words; +headerparser.getHeaderTokens = getHeaderTokens; +headerparser.parseAddressingHeader = parseAddressingHeader; +headerparser.parseDateHeader = parseDateHeader; +headerparser.parseParameterHeader = parseParameterHeader; +headerparser.parseStructuredHeader = parseStructuredHeader; +return Object.freeze(headerparser); + +}); + +//////////////////////////////////////////////////////////////////////////////// +// JavaScript Raw MIME Parser // +//////////////////////////////////////////////////////////////////////////////// + +/** + * The parser implemented in this file produces a MIME part tree for a given + * input message via a streaming callback interface. It does not, by itself, + * understand concepts like attachments (hence the term 'Raw'); the consumer + * must translate output into such a format. + * + * Charsets: + * The MIME specifications permit a single message to contain multiple charsets + * (or perhaps none) as raw octets. As JavaScript strings are implicitly + * implemented in UTF-16, it is possible that some engines will attempt to + * convert these strings using an incorrect charset or simply fail to convert + * them at all. This parser assumes that its input is in the form of a "binary + * string", a string that uses only the first 256 characters of Unicode to + * represent the individual octets. To verify that charsets are not getting + * mangled elsewhere in the pipeline, the auxiliary test file test/data/charsets + * can be used. + * + * This parser attempts to hide the charset details from clients as much as + * possible. The resulting values of structured headers are always converted + * into proper Unicode strings before being exposed to clients; getting at the + * raw binary string data can only be done via getRawHeader. The .charset + * parameter on header objects, if changed, changes the fallback charset used + * for headers. It is initialized to the presumed charset of the corresponding + * part, taking into account the charset and force-charset options of the + * parser. Body parts are only converted into Unicode strings if the strformat + * option is set to Unicode. Even then, only the bodies of parts with a media + * type of text are converted to Unicode strings using available charset data; + * other parts are retained as Uint8Array objects. + * + * Part numbering: + * Since the output is a streaming format, individual parts are identified by a + * numbering scheme. The intent of the numbering scheme for parts is to comply + * with the part numbers as dictated by RFC 3501 as much possible; however, + * that scheme does have several edge cases which would, if strictly followed, + * make it impossible to refer to certain parts of the message. In addition, we + * wish to make it possible to refer to parts which are not discoverable in the + * original MIME tree but are still viewable as parts. The part numbering + * scheme is as follows: + * - Individual sections of a multipart/* body are numbered in increasing order + * sequentially, starting from 1. Note that the prologue and the epilogue of + * a multipart/* body are not considered entities and are therefore not + * included in the part numbering scheme (there is no way to refer to them). + * - The numbers of multipart/* parts are separated by `.' characters. + * - The outermost message is referred to by use of the empty string. + * --> The following segments are not accounted for by IMAP part numbering. <-- + * - The body of any message/rfc822 or similar part is distinguished from the + * message part as a whole by appending a `$' character. This does not apply + * to the outermost message/rfc822 envelope. + */ + +def('mimeparser', function(require) { +"use strict"; + +var mimeutils = require('./mimeutils'); +var headerparser = require('./headerparser'); +var spellings = require('./structuredHeaders').spellings; + +/** + * An object that represents the structured MIME headers for a message. + * + * This class is primarily used as the 'headers' parameter in the startPart + * callback on handlers for MimeParser. As such, it is designed to do the right + * thing in common cases as much as possible, with some advanced customization + * possible for clients that need such flexibility. + * + * In a nutshell, this class stores the raw headers as an internal Map. The + * structured headers are not computed until they are actually used, which means + * that potentially expensive structuring (e.g., doing manual DKIM validation) + * can be performed as a structured decoder without impeding performance for + * those who just want a few common headers. + * + * The outer API of this class is intended to be similar to a read-only Map + * object (complete with iterability support), with a few extra properties to + * represent things that are hard to determine properly from headers. The keys + * used are "preferred spellings" of the headers, although the get and has + * methods will accept header parameters of any case. Preferred spellings are + * derived from the name passed to addStructuredDecoder/addStructuredEncoder; if + * no structured decoder has been registered, then the name capitalizes the + * first letter of every word in the header name. + * + * Extra properties compared to a Map object are: + * - charset: This field represents the assumed charset of the associated MIME + * body. It is prefilled using a combination of the charset and force-charset + * options on the associated MimeParser instance as well as attempting to find + * a charset parameter in the Content-Type header. + * + * If the force-charset option is false, the charset is guessed first using + * the Content-Type header's charset parameter, falling back to the charset + * option if it is present. If the force-charset option is true, the charset + * is initially set to the charset option. This initial guessed value can be + * overridden at any time by simply setting the field on this object. + * + * The charset is better reflected as a parameter of the body rather than the + * headers; this is ultimately the charset parameter that will be used if a + * body part is being converted to a Unicode strformat. Headers are converted + * using headerparser.convert8BitHeader, and this field is used as the + * fallbackCharset parameter, which will always to attempt to decode as UTF-8 + * first (in accordance with RFC 6532) and will refuse to decode as UTF-16 or + * UTF-32, as ASCII is not a subset of those charsets. + * + * - rawHeaderText: This read-only field contains the original header text from + * which headers were parsed, preserving case and whitespace (including + * alternate line endings instead of CRLF) exactly. If the header text begins + * with the mbox delimiter (i.e., a line that begins with "From "), then that + * is excluded from the rawHeaderText value and is not reflected anywhere in + * this object. + * + * - contentType: This field contains the structured representation of the + * Content-Type header, if it is present. If it is not present, it is set to + * the structured representation of the default Content-Type for a part (as + * this data is not easily guessed given only MIME tree events). + * + * The constructor for these objects is not externally exported, and thus they + * can only be created via MimeParser. + * + * @param rawHeaderText {BinaryString} The contents of the MIME headers to be + * parsed. + * @param options {Object} Options for the header parser. + * @param options.stripcontinuations {Boolean} If true, elide CRLFs from the + * raw header output. + */ +function StructuredHeaders(rawHeaderText, options) { + // An individual header is terminated by a CRLF, except if the CRLF is + // followed by a SP or TAB. Use negative lookahead to capture the latter case, + // and don't capture the strings or else split results get nasty. + let values = rawHeaderText.split(/(?:\r\n|\n)(?![ \t])|\r(?![ \t\n])/); + + // Ignore the first "header" if it begins with an mbox delimiter + if (values.length > 0 && values[0].substring(0, 5) == "From ") { + values.shift(); + // Elide the mbox delimiter from this._headerData + if (values.length == 0) + rawHeaderText = ''; + else + rawHeaderText = rawHeaderText.substring(rawHeaderText.indexOf(values[0])); + } + + let headers = new Map(); + for (let i = 0; i < values.length; i++) { + // Look for a colon. If it's not present, this header line is malformed, + // perhaps by premature EOF or similar. + let colon = values[i].indexOf(":"); + if (colon >= 0) { + var header = values[i].substring(0, colon); + var val = values[i].substring(colon + 1).trim(); + if (options.stripcontinuations) + val = val.replace(/[\r\n]/g, ''); + } else { + var header = values[i]; + var val = ''; + } + + // Canonicalize the header in lower-case form. + header = header.trim().toLowerCase(); + // Omit "empty" headers + if (header == '') + continue; + + // We keep an array of values for each header, since a given header may be + // repeated multiple times. + if (headers.has(header)) { + headers.get(header).push(val); + } else { + headers.set(header, [val]); + } + } + + /** + * A map of header names to arrays of raw values found in this header block. + * @private + */ + this._rawHeaders = headers; + /** + * Cached results of structured header parsing. + * @private + */ + this._cachedHeaders = new Map(); + Object.defineProperty(this, "rawHeaderText", + {get: function () { return rawHeaderText; }}); + Object.defineProperty(this, "size", + {get: function () { return this._rawHeaders.size; }}); + Object.defineProperty(this, "charset", { + get: function () { return this._charset; }, + set: function (value) { + this._charset = value; + // Clear the cached headers, since this could change their values + this._cachedHeaders.clear(); + } + }); + + // Default to the charset, until the message parser overrides us. + if ('charset' in options) + this._charset = options.charset; + else + this._charset = null; + + // If we have a Content-Type header, set contentType to return the structured + // representation. We don't set the value off the bat, since we want to let + // someone who changes the charset affect the values of 8-bit parameters. + Object.defineProperty(this, "contentType", { + configurable: true, + get: function () { return this.get('Content-Type'); } + }); +} + +/** + * Get a raw header. + * + * Raw headers are an array of the header values, listed in order that they were + * specified in the header block, and without any attempt to convert charsets or + * apply RFC 2047 decoding. For example, in the following message (where the + * <XX> is meant to represent binary-octets): + * + * X-Header: Value A + * X-Header: V<C3><A5>lue B + * Header2: Q + * + * the result of calling getRawHeader('X-Header') or getRawHeader('x-header') + * would be ['Value A', 'V\xC3\xA5lue B'] and the result of + * getRawHeader('Header2') would be ['Q']. + * + * @param headerName {String} The header name for which to get header values. + * @returns {BinaryString[]} The raw header values (with no charset conversion + * applied). + */ +StructuredHeaders.prototype.getRawHeader = function (headerName) { + return this._rawHeaders.get(headerName.toLowerCase()); +}; + +/** + * Retrieve a structured version of the header. + * + * If there is a registered structured decoder (registration happens via + * headerparser.addStructuredDecoder), then the result of calling that decoder + * on the charset-corrected version of the header is returned. Otherwise, the + * values are charset-corrected and RFC 2047 decoding is applied as if the + * header were an unstructured header. + * + * A substantial set of headers have pre-registed structured decoders, which, in + * some cases, are unable to be overridden due to their importance in the + * functioning of the parser code itself. + * + * @param headerName {String} The header name for which to get the header value. + * @returns The structured header value of the output. + */ +StructuredHeaders.prototype.get = function (headerName) { + // Normalize the header name to lower case + headerName = headerName.toLowerCase(); + + // First, check the cache for the header value + if (this._cachedHeaders.has(headerName)) + return this._cachedHeaders.get(headerName); + + // Not cached? Grab it [propagating lack of header to caller] + let headerValue = this._rawHeaders.get(headerName); + if (headerValue === undefined) + return headerValue; + + // Convert the header to Unicode + let charset = this.charset; + headerValue = headerValue.map(function (value) { + return headerparser.convert8BitHeader(value, charset); + }); + + // If there is a structured decoder, use that; otherwise, assume that the + // header is unstructured and only do RFC 2047 conversion + let structured; + try { + structured = headerparser.parseStructuredHeader(headerName, headerValue); + } catch (e) { + structured = headerValue.map(function (value) { + return headerparser.decodeRFC2047Words(value); + }); + } + + // Cache the result and return it + this._cachedHeaders.set(headerName, structured); + return structured; +}; + +/** + * Check if the message has the given header. + * + * @param headerName {String} The header name for which to get the header value. + * @returns {Boolean} True if the header is present in this header block. + */ +StructuredHeaders.prototype.has = function (headerName) { + // Check for presence in the raw headers instead of cached headers. + return this._rawHeaders.has(headerName.toLowerCase()); +}; + +// Make a custom iterator. Presently, support for Symbol isn't yet present in +// SpiderMonkey (or V8 for that matter), so type-pun the name for now. +var JS_HAS_SYMBOLS = typeof Symbol === "function"; +var ITERATOR_SYMBOL = JS_HAS_SYMBOLS ? Symbol.iterator : "@@iterator"; + +/** + * An equivalent of Map.@@iterator, applied to the structured header + * representations. This is the function that makes + * for (let [header, value] of headers) work properly. + */ +StructuredHeaders.prototype[ITERATOR_SYMBOL] = function*() { + // Iterate over all the raw headers, and use the cached headers to retrieve + // them. + for (let headerName of this.keys()) { + yield [headerName, this.get(headerName)]; + } +}; + +/** + * An equivalent of Map.forEach, applied to the structured header + * representations. + * + * @param callback {Function(value, name, headers)} The callback to call for + * each header/value combo. + * @param thisarg {Object} The parameter that will be + * the |this| of the callback. + */ +StructuredHeaders.prototype.forEach = function (callback, thisarg) { + for (let [header, value] of this) { + callback.call(thisarg, value, header, this); + } +}; + +/** + * An equivalent of Map.entries, applied to the structured header + * representations. + */ +StructuredHeaders.prototype.entries = + StructuredHeaders.prototype[Symbol.iterator]; + +/// This function maps lower case names to a pseudo-preferred spelling. +function capitalize(headerName) { + return headerName.replace(/\b[a-z]/g, function (match) { + return match.toUpperCase(); + }); +} + +/** + * An equivalent of Map.keys, applied to the structured header representations. + */ +StructuredHeaders.prototype.keys = function*() { + for (let name of this._rawHeaders.keys()) { + yield spellings.get(name) || capitalize(name); + } +}; + +/** + * An equivalent of Map.values, applied to the structured header + * representations. + */ +StructuredHeaders.prototype.values = function* () { + for (let [, value] of this) { + yield value; + } +}; + + +/** + * A MIME parser. + * + * The inputs to the constructor consist of a callback object which receives + * information about the output data and an optional object containing the + * settings for the parser. + * + * The first parameter, emitter, is an object which contains several callbacks. + * Note that any and all of these methods are optional; the parser will not + * crash if one is missing. The callbacks are as follows: + * startMessage() + * Called when the stream to be parsed has started delivering data. This + * will be called exactly once, before any other call. + * endMessage() + * Called after all data has been delivered and the message parsing has + * been completed. This will be called exactly once, after any other call. + * startPart(string partNum, object headers) + * Called after the headers for a body part (including the top-level + * message) have been parsed. The first parameter is the part number (see + * the discussion on part numbering). The second parameter is an instance + * of StructuredHeaders that represents all of the headers for the part. + * endPart(string partNum) + * Called after all of the data for a body part (including sub-parts) has + * been parsed. The first parameter is the part number. + * deliverPartData(string partNum, {string,typedarray} data) + * Called when some data for a body part has been delivered. The first + * parameter is the part number. The second parameter is the data which is + * being delivered; the exact type of this data depends on the options + * used. Note that data is only delivered for leaf body parts. + * + * The second parameter, options, is an optional object containing the options + * for the parser. The following are the options that the parser may use: + * pruneat: <string> [default=""] + * Treat the message as starting at the given part number, so that no parts + * above <string> are returned. + * bodyformat: one of {none, raw, nodecode, decode} [default=nodecode] + * How to return the bodies of parts: + * none: no part data is returned + * raw: the body of the part is passed through raw + * nodecode: the body is passed through without decoding QP/Base64 + * decode: quoted-printable and base64 are fully decoded + * strformat: one of {binarystring, unicode, typedarray} [default=binarystring] + * How to treat output strings: + * binarystring: Data is a JS string with chars in the range [\x00-\xff] + * unicode: Data for text parts is converted to UTF-16; data for other + * parts is a typed array buffer, akin to typedarray. + * typedarray: Data is a JS typed array buffer + * charset: <string> [default=""] + * What charset to assume if no charset information is explicitly provided. + * This only matters if strformat is unicode. See above note on charsets + * for more details. + * force-charset: <boolean> [default=false] + * If true, this coerces all types to use the charset option, even if the + * message specifies a different content-type. + * stripcontinuations: <boolean> [default=true] + * If true, then the newlines in headers are removed in the returned + * header objects. + * onerror: <function(thrown error)> [default = nop-function] + * An error function that is called if an emitter callback throws an error. + * By default, such errors are swallowed by the parser. If you want the + * parser itself to throw an error, rethrow it via the onerror function. + */ +function MimeParser(emitter, options) { + /// The actual emitter + this._emitter = emitter; + /// Options for the parser (those listed here are defaults) + this._options = { + pruneat: "", + bodyformat: "nodecode", + strformat: "binarystring", + stripcontinuations: true, + charset: "", + "force-charset": false, + onerror: function swallow(error) {} + }; + // Load the options as a copy here (prevents people from changing on the fly). + if (options) + for (var opt in options) { + this._options[opt] = options[opt]; + } + + // Ensure that the error function is in fact a function + if (typeof this._options.onerror != "function") + throw new Exception("onerror callback must be a function"); + + // Reset the parser + this.resetParser(); +} + +/** + * Resets the parser to read a new message. This method need not be called + * immediately after construction. + */ +MimeParser.prototype.resetParser = function () { + /// Current parser state + this._state = PARSING_HEADERS; + /// Input data that needs to be held for buffer conditioning + this._holdData = ''; + /// Complete collection of headers (also used to accumulate _headerData) + this._headerData = ''; + /// Whether or not emitter.startMessage has been called + this._triggeredCall = false; + + /// Splitting input + this._splitRegex = this._handleSplit = undefined; + /// Subparsing + this._subparser = this._subPartNum = undefined; + /// Data that has yet to be consumed by _convertData + this._savedBuffer = ''; + /// Convert data + this._convertData = undefined; + /// String decoder + this._decoder = undefined; +}; + +/** + * Deliver a buffer of data to the parser. + * + * @param buffer {BinaryString} The raw data to add to the message. + */ +MimeParser.prototype.deliverData = function (buffer) { + // In ideal circumstances, we'd like to parse the message all at once. In + // reality, though, data will be coming to us in packets. To keep the amount + // of saved state low, we want to make basic guarantees about how packets get + // delivered. Our basic model is a twist on line-buffering, as the format of + // MIME and messages make it hard to not do so: we can handle multiple lines + // at once. To ensure this, we start by conditioning the packet by + // withholding data to make sure that the internal deliveries have the + // guarantees. This implies that we need to do the following steps: + // 1. We don't know if a `\r' comes from `\r\n' or the old mac line ending + // until we see the next character. So withhold the last `\r'. + // 2. Ensure that every packet ends on a newline. So scan for the end of the + // line and withhold until the \r\n comes through. + // [Note that this means that an input message that uses \r line endings and + // is being passed to us via a line-buffered input is going to have most of + // its data being withhold until the next buffer. Since \r is so uncommon of + // a line ending in modern times, this is acceptable lossage.] + // 3. Eliminate empty packets. + + // Add in previously saved data + if (this._holdData) { + buffer = this._holdData + buffer; + this._holdData = ''; + } + + // Condition the input, so that we get the multiline-buffering mentioned in + // the above comment. + if (buffer.length > 0) { + [buffer, this._holdData] = conditionToEndOnCRLF(buffer); + } + + // Ignore 0-length buffers. + if (buffer.length == 0) + return; + + // Signal the beginning, if we haven't done so. + if (!this._triggeredCall) { + this._callEmitter("startMessage"); + this._triggeredCall = true; + } + + // Finally, send it the internal parser. + this._dispatchData("", buffer, true); +} + +/** + * Ensure that a set of data always ends in an end-of-line character. + * + * @param buffer {BinaryString} The data with no guarantees about where it ends. + * @returns {BinaryString[]} An array of 2 binary strings where the first string + * ends in a newline and the last string contains the + * text in buffer following the first string. + */ +function conditionToEndOnCRLF(buffer) { + // Find the last occurrence of '\r' or '\n' to split the string. However, we + // don't want to consider '\r' if it is the very last character, as we need + // the next packet to tell if the '\r' is the beginning of a CRLF or a line + // ending by itself. + let lastCR = buffer.lastIndexOf('\r', buffer.length - 2); + let lastLF = buffer.lastIndexOf('\n'); + let end = lastLF > lastCR ? lastLF : lastCR; + return [buffer.substring(0, end + 1), buffer.substring(end + 1)]; +}; + +/** + * Tell the parser that all of the data has been delivered. + * + * This will flush all of the internal state of the parser. + */ +MimeParser.prototype.deliverEOF = function () { + // Start of input buffered too long? Call start message now. + if (!this._triggeredCall) { + this._triggeredCall = true; + this._callEmitter("startMessage"); + } + // Force a flush of all of the data. + if (this._holdData) + this._dispatchData("", this._holdData, true); + this._dispatchEOF(""); + // Signal to the emitter that we're done. + this._callEmitter("endMessage"); +}; + +/** + * Calls a method on the emitter safely. + * + * This method ensures that errors in the emitter call won't cause the parser + * to exit with an error, unless the user wants it to. + * + * @param funcname {String} The function name to call on the emitter. + * @param args... Extra arguments to pass into the emitter callback. + */ +MimeParser.prototype._callEmitter = function (funcname) { + if (this._emitter && funcname in this._emitter) { + let args = Array.prototype.splice.call(arguments, 1); + if (args.length > 0 && this._willIgnorePart(args[0])) { + // partNum is always the first argument, so check to make sure that it + // satisfies our emitter's pruneat requirement. + return; + } + try { + this._emitter[funcname].apply(this._emitter, args); + } catch (e) { + // We ensure that the onerror attribute in options is a function, so this + // is always safe. + this._options.onerror(e); + } + } +}; + +/** + * Helper function to decide if a part's output will never be seen. + * + * @param part {String} The number of the part. + * @returns {Boolean} True if the emitter is not interested in this part. + */ +MimeParser.prototype._willIgnorePart = function (part) { + if (this._options["pruneat"]) { + let match = this._options["pruneat"]; + let start = part.substr(0, match.length); + // It needs to start with and follow with a new part indicator + // (i.e., don't let 10 match with 1, but let 1.1 or 1$ do so) + if (start != match || (match.length < part.length && + "$.".indexOf(part[match.length]) == -1)) + return true; + } + return false; +}; + +////////////////////// +// MIME parser core // +////////////////////// + +// This MIME parser is a stateful parser; handling of the MIME tree is mostly +// done by creating new parsers and feeding data to them manually. In parallel +// to the externally-visible deliverData and deliverEOF, the two methods +// _dispatchData and _dispatchEOF are the internal counterparts that do the +// main work of moving data to where it needs to go; helper functions are used +// to handle translation. +// +// The overall flow of the parser is this. First, it buffers all of the data +// until the dual-CRLF pattern is noticed. Once that is found, it parses the +// entire header chunk at once. As a result of header parsing, the parser enters +// one of three modes for handling data, and uses a special regex to change +// modes and handle state changes. Specific details about the states the parser +// can be in are as follows: +// PARSING_HEADERS: The input buffer is concatenated to the currently-received +// text, which is then searched for the CRLFCRLF pattern. If found, the data +// is split at this boundary; the first chunk is parsed using _parseHeaders, +// and the second chunk will fall through to buffer processing. After +// splitting, the headers are deliverd via the emitter, and _startBody is +// called to set up state for the parser. +// SEND_TO_BLACK_HOLE: All data in the input is ignored. +// SEND_TO_EMITTER: All data is passed into the emitter, if it is desired. +// Data can be optionally converted with this._convertData. +// SEND_TO_SUBPARSER: All data is passed into the subparser's _dispatchData +// method, using _subPartNum as the part number and _subparser as the object +// to call. Data can be optionally converted first with this._convertData. +// +// Additional state modifications can be done using a regex in _splitRegex and +// the callback method this._handleSplit(partNum, regexResult). The _handleSplit +// callback is free to do any modification to the current parser, including +// modifying the _splitRegex value. Packet conditioning guarantees that every +// buffer string passed into _dispatchData will have started immediately after a +// newline character in the fully assembled message. +// +// The this._convertData method, if present, is expected to return an array of +// two values, [{typedarray, string} decoded_buffer, string unused_buffer], and +// has as its arguments (string buffer, bool moreToCome). +// +// The header parsing by itself does very little parsing, only parsing as if all +// headers were unstructured fields. Values are munged so that embedded newlines +// are stripped and the result is also trimmed. Headers themselves are +// canonicalized into lower-case. + + +// Parser states. See the large comment above. +var PARSING_HEADERS = 1; +var SEND_TO_BLACK_HOLE = 2; +var SEND_TO_EMITTER = 3; +var SEND_TO_SUBPARSER = 4; + +/** + * Main dispatch for incoming packet data. + * + * The incoming data needs to have been sanitized so that each packet begins on + * a newline boundary. The part number for the current parser also needs to be + * passed in. The checkSplit parameter controls whether or not the data in + * buffer needs to be checked against _splitRegex; this is used internally for + * the mechanics of splitting and should otherwise always be true. + * + * @param partNum {String} The part number being currently parsed. + * @param buffer {BinaryString} The text (conditioned as mentioned above) to + * pass to the parser. + * @param checkSplit {Boolean} If true, split the text using _splitRegex. + * This is set to false internally to handle + * low-level splitting details. + */ +MimeParser.prototype._dispatchData = function (partNum, buffer, checkSplit) { + // Are we parsing headers? + if (this._state == PARSING_HEADERS) { + this._headerData += buffer; + // Find the end of the headers--either it's a CRLF at the beginning (in + // which case we have no headers), or it's a pair of CRLFs. + let result = /(?:^(?:\r\n|[\r\n]))|(\r\n|[\r\n])\1/.exec(this._headerData); + if (result != null) { + // If we found the end of headers, split the data at this point and send + // the stuff after the double-CRLF into the later body parsing. + let headers = this._headerData.substr(0, result.index); + buffer = this._headerData.substring(result.index + result[0].length); + this._headerData = headers; + this._headers = this._parseHeaders(); + this._callEmitter("startPart", partNum, this._headers); + this._startBody(partNum); + } else { + return; + } + } + + // We're in the middle of the body. Start by testing the split regex, to see + // if there are many things that need to be done. + if (checkSplit && this._splitRegex) { + let splitResult = this._splitRegex.exec(buffer); + if (splitResult) { + // Pass the text before the split through the current state. + let start = splitResult.index, len = splitResult[0].length; + if (start > 0) + this._dispatchData(partNum, buffer.substr(0, start), false); + + // Tell the handler that we've seen the split. Note that this can change + // any method on `this'. + this._handleSplit(partNum, splitResult); + + // Send the rest of the data to where it needs to go. There could be more + // splits in the data, so watch out! + buffer = buffer.substring(start + len); + if (buffer.length > 0) + this._dispatchData(partNum, buffer, true); + return; + } + } + + // Where does the data go? + if (this._state == SEND_TO_BLACK_HOLE) { + // Don't send any data when going to the black hole. + return; + } else if (this._state == SEND_TO_EMITTER) { + // Don't pass body data if the format is to be none + let passData = this._options["bodyformat"] != "none"; + if (!passData || this._willIgnorePart(partNum)) + return; + buffer = this._applyDataConversion(buffer, this._options["strformat"]); + if (buffer.length > 0) + this._callEmitter("deliverPartData", partNum, buffer); + } else if (this._state == SEND_TO_SUBPARSER) { + buffer = this._applyDataConversion(buffer, "binarystring"); + if (buffer.length > 0) + this._subparser._dispatchData(this._subPartNum, buffer, true); + } +}; + +/** + * Output data using the desired output format, saving data if data conversion + * needs extra data to be saved. + * + * @param buf {BinaryString} The data to be sent to the output. + * @param type {String} The type of the data to output. Valid values are + * the same as the strformat option. + * @returns Coerced and converted data that can be sent to the emitter or + * subparser. + */ +MimeParser.prototype._applyDataConversion = function (buf, type) { + // If we need to convert data, do so. + if (this._convertData) { + // Prepend leftover data from the last conversion. + buf = this._savedBuffer + buf; + [buf, this._savedBuffer] = this._convertData(buf, true); + } + return this._coerceData(buf, type, true); +}; + +/** + * Coerce the input buffer into the given output type. + * + * @param buffer {BinaryString|Uint8Array} The data to be converted. + * @param type {String} The type to convert the data to. + * @param more {boolean} If true, this function will never be + * called again. + * @returns {BinaryString|String|Uint8Array} The desired output format. + */ +/// Coerces the buffer (a string or typedarray) into a given type +MimeParser.prototype._coerceData = function (buffer, type, more) { + if (typeof buffer == "string") { + // string -> binarystring is a nop + if (type == "binarystring") + return buffer; + // Either we're going to array or unicode. Both people need the array + var typedarray = mimeutils.stringToTypedArray(buffer); + // If it's unicode, do the coercion from the array + // If its typedarray, just return the synthesized one + return type == "unicode" ? this._coerceData(typedarray, "unicode", more) + : typedarray; + } else if (type == "binarystring") { + // Doing array -> binarystring + return mimeutils.typedArrayToString(buffer); + } else if (type == "unicode") { + // Doing array-> unicode: Use the decoder set up earlier to convert + if (this._decoder) + return this._decoder.decode(buffer, {stream: more}); + // If there is no charset, just return the typed array instead. + return buffer; + } + throw new Error("Invalid type: " + type); +}; + +/** + * Signal that no more data will be dispatched to this parser. + * + * @param partNum {String} The part number being currently parsed. + */ +MimeParser.prototype._dispatchEOF = function (partNum) { + if (this._state == PARSING_HEADERS) { + // Unexpected EOF in headers. Parse them now and call startPart/endPart + this._headers = this._parseHeaders(); + this._callEmitter("startPart", partNum, this._headers); + } else if (this._state == SEND_TO_SUBPARSER) { + // Pass in any lingering data + if (this._convertData && this._savedBuffer) + this._subparser._dispatchData(this._subPartNum, + this._convertData(this._savedBuffer, false)[0], true); + this._subparser._dispatchEOF(this._subPartNum); + // Clean up after ourselves + this._subparser = null; + } else if (this._convertData && this._savedBuffer) { + // Convert lingering data + let [buffer, ] = this._convertData(this._savedBuffer, false); + buffer = this._coerceData(buffer, this._options["strformat"], false); + if (buffer.length > 0) + this._callEmitter("deliverPartData", partNum, buffer); + } + + // We've reached EOF for this part; tell the emitter + this._callEmitter("endPart", partNum); +}; + +/** + * Produce a dictionary of all headers as if they were unstructured fields. + * + * @returns {StructuredHeaders} The structured header objects for the header + * block. + */ +MimeParser.prototype._parseHeaders = function () { + let headers = new StructuredHeaders(this._headerData, this._options); + + // Fill the headers.contentType parameter of headers. + let contentType = headers.get('Content-Type'); + if (typeof contentType === "undefined") { + contentType = headerparser.parseStructuredHeader('Content-Type', + this._defaultContentType || 'text/plain'); + Object.defineProperty(headers, "contentType", { + get: function () { return contentType; } + }); + } else { + Object.defineProperty(headers, "contentType", { configurable: false }); + } + + // Find the charset for the current part. If the user requested a forced + // conversion, use that first. Otherwise, check the content-type for one and + // fallback to a default if it is not present. + let charset = ''; + if (this._options["force-charset"]) + charset = this._options["charset"]; + else if (contentType.has("charset")) + charset = contentType.get("charset"); + else + charset = this._options["charset"]; + headers.charset = charset; + + // Retain a copy of the charset so that users don't override our decision for + // decoding body parts. + this._charset = charset; + return headers; +}; + +/** + * Initialize the parser state for the body of this message. + * + * @param partNum {String} The part number being currently parsed. + */ +MimeParser.prototype._startBody = function Parser_startBody(partNum) { + let contentType = this._headers.contentType; + + // Should the bodyformat be raw, we just want to pass through all data without + // trying to interpret it. + if (this._options["bodyformat"] == "raw" && + partNum == this._options["pruneat"]) { + this._state = SEND_TO_EMITTER; + return; + } + + // The output depents on the content-type. Basic rule of thumb: + // 1. Discrete media types (text, video, audio, image, application) are passed + // through with no alterations beyond Content-Transfer-Encoding unpacking. + // 2. Everything with a media type of multipart is treated the same. + // 3. Any message/* type that acts like a mail message (rfc822, news, global) + // is parsed as a header/body pair again. Most of the other message/* types + // have similar structures, but they don't have cascading child subparts, + // so it's better to pass their entire contents to the emitter and let the + // consumer deal with them. + // 4. For untyped data, there needs to be no Content-Type header. This helps + // avoid false positives. + if (contentType.mediatype == 'multipart') { + // If there's no boundary type, everything will be part of the prologue of + // the multipart message, so just feed everything into a black hole. + if (!contentType.has('boundary')) { + this._state = SEND_TO_BLACK_HOLE; + return; + } + // The boundary of a multipart message needs to start with -- and be at the + // beginning of the line. If -- is after the boundary, it represents the + // terminator of the multipart. After the line, there may be only whitespace + // and then the CRLF at the end. Since the CRLFs in here are necessary for + // distinguishing the parts, they are not included in the subparts, so we + // need to capture them in the regex as well to prevent them leaking out. + this._splitRegex = new RegExp('(\r\n|[\r\n]|^)--' + + contentType.get('boundary').replace(/[\\^$*+?.()|{}[\]]/g, '\\$&') + + '(--)?[ \t]*(?:\r\n|[\r\n]|$)'); + this._handleSplit = this._whenMultipart; + this._subparser = new MimeParser(this._emitter, this._options); + // multipart/digest defaults to message/rfc822 instead of text/plain + if (contentType.subtype == "digest") + this._subparser._defaultContentType = "message/rfc822"; + + // All text before the first boundary and after the closing boundary are + // supposed to be ignored ("must be ignored", according to RFC 2046 §5.1.1); + // in accordance with these wishes, ensure they don't get passed to any + // deliverPartData. + this._state = SEND_TO_BLACK_HOLE; + + // Multipart MIME messages stipulate that the final CRLF before the boundary + // delimiter is not matched. When the packet ends on a CRLF, we don't know + // if the next text could be the boundary. Therefore, we need to withhold + // the last line of text to be sure of what's going on. The _convertData is + // how we do this, even though we're not really converting any data. + this._convertData = function mpart_no_leak_crlf(buffer, more) { + let splitPoint = buffer.length; + if (more) { + if (buffer.charAt(splitPoint - 1) == '\n') + splitPoint--; + if (splitPoint >= 0 && buffer.charAt(splitPoint - 1) == '\r') + splitPoint--; + } + let res = conditionToEndOnCRLF(buffer.substring(0, splitPoint)); + let preLF = res[0]; + let rest = res[1]; + return [preLF, rest + buffer.substring(splitPoint)]; + } + } else if (contentType.type == 'message/rfc822' || + contentType.type == 'message/global' || + contentType.type == 'message/news') { + // The subpart is just another header/body pair that goes to EOF, so just + // return the parse from that blob + this._state = SEND_TO_SUBPARSER; + this._subPartNum = partNum + "$"; + this._subparser = new MimeParser(this._emitter, this._options); + + // So, RFC 6532 happily allows message/global types to have CTE applied. + // This means that subparts would need to be decoded to determine their + // contents properly. There seems to be some evidence that message/rfc822 + // that is illegally-encoded exists in the wild, so be lenient and decode + // for any message/* type that gets here. + let cte = this._extractHeader('content-transfer-encoding', ''); + if (cte in ContentDecoders) + this._convertData = ContentDecoders[cte]; + } else { + // Okay, we just have to feed the data into the output + this._state = SEND_TO_EMITTER; + if (this._options["bodyformat"] == "decode") { + // If we wish to decode, look it up in one of our decoders. + let cte = this._extractHeader('content-transfer-encoding', ''); + if (cte in ContentDecoders) + this._convertData = ContentDecoders[cte]; + } + } + + // Set up the encoder for charset conversions; only do this for text parts. + // Other parts are almost certainly binary, so no translation should be + // applied to them. + if (this._options["strformat"] == "unicode" && + contentType.mediatype == "text") { + // If the charset is nonempty, initialize the decoder + if (this._charset !== "") { + this._decoder = new TextDecoder(this._charset); + } else { + // There's no charset we can use for decoding, so pass through as an + // identity encoder or otherwise this._coerceData will complain. + this._decoder = { + decode: function identity_decoder(buffer) { + return MimeParser.prototype._coerceData(buffer, "binarystring", true); + } + }; + } + } else { + this._decoder = null; + } +}; + +// Internal split handling for multipart messages. +/** + * When a multipary boundary is found, handle the process of managing the + * subparser state. This is meant to be used as a value for this._handleSplit. + * + * @param partNum {String} The part number being currently parsed. + * @param lastResult {Array} The result of the regular expression match. + */ +MimeParser.prototype._whenMultipart = function (partNum, lastResult) { + // Fix up the part number (don't do '' -> '.4' and don't do '1' -> '14') + if (partNum != "") partNum += "."; + if (!this._subPartNum) { + // No count? This means that this is the first time we've seen the boundary, + // so do some initialization for later here. + this._count = 1; + } else { + // If we did not match a CRLF at the beginning of the line, strip CRLF from + // the saved buffer. We do this in the else block because it is not + // necessary for the prologue, since that gets ignored anyways. + if (this._savedBuffer != '' && lastResult[1] === '') { + let useEnd = this._savedBuffer.length - 1; + if (this._savedBuffer[useEnd] == '\n') + useEnd--; + if (useEnd >= 0 && this._savedBuffer[useEnd] == '\r') + useEnd--; + this._savedBuffer = this._savedBuffer.substring(0, useEnd + 1); + } + // If we have saved data and we matched a CRLF, pass the saved data in. + if (this._savedBuffer != '') + this._subparser._dispatchData(this._subPartNum, this._savedBuffer, true); + // We've seen the boundary at least once before, so this must end a subpart. + // Tell that subpart that it has reached EOF. + this._subparser._dispatchEOF(this._subPartNum); + } + this._savedBuffer = ''; + + // The regex feeder has a capture on the (--)?, so if its result is present, + // then we have seen the terminator. Alternatively, the message may have been + // mangled to exclude the terminator, so also check if EOF has occurred. + if (lastResult[2] == undefined) { + this._subparser.resetParser(); + this._state = SEND_TO_SUBPARSER; + this._subPartNum = partNum + this._count; + this._count += 1; + } else { + // Ignore the epilogue + this._splitRegex = null; + this._state = SEND_TO_BLACK_HOLE; + } +}; + +/** + * Return the structured header from the current header block, or a default if + * it is not present. + * + * @param name {String} The header name to get. + * @param dflt {String} The default MIME value of the header. + * @returns The structured representation of the header. + */ +MimeParser.prototype._extractHeader = function (name, dflt) { + name = name.toLowerCase(); // Normalize name + return this._headers.has(name) ? this._headers.get(name) : + headerparser.parseStructuredHeader(name, [dflt]); +}; + +var ContentDecoders = {}; +ContentDecoders['quoted-printable'] = mimeutils.decode_qp; +ContentDecoders['base64'] = mimeutils.decode_base64; + +return MimeParser; +}); +def('headeremitter', function(require) { +/** + * This module implements the code for emitting structured representations of + * MIME headers into their encoded forms. The code here is a companion to, + * but completely independent of, jsmime.headerparser: the structured + * representations that are used as input to the functions in this file are the + * same forms that would be parsed. + */ + +"use strict"; + +var mimeutils = require('./mimeutils'); + +// Get the default structured encoders and add them to the map +var structuredHeaders = require('./structuredHeaders'); +var encoders = new Map(); +var preferredSpellings = structuredHeaders.spellings; +for (let [header, encoder] of structuredHeaders.encoders) { + addStructuredEncoder(header, encoder); +} + +/// Clamp a value in the range [min, max], defaulting to def if it is undefined. +function clamp(value, min, max, def) { + if (value === undefined) + return def; + if (value < min) + return min; + if (value > max) + return max; + return value; +} + +/** + * An object that can assemble structured header representations into their MIME + * representation. + * + * The character-counting portion of this class operates using individual JS + * characters as its representation of logical character, which is not the same + * as the number of octets used as UTF-8. If non-ASCII characters are to be + * included in headers without some form of encoding, then care should be taken + * to set the maximum line length to account for the mismatch between character + * counts and octet counts: the maximum line is 998 octets, which could be as + * few as 332 JS characters (non-BMP characters, although they take up 4 octets + * in UTF-8, count as 2 in JS strings). + * + * This code takes care to only insert line breaks at the higher-level breaking + * points in a header (as recommended by RFC 5322), but it may need to resort to + * including them more aggressively if this is not possible. If even aggressive + * line-breaking cannot allow a header to be emitted without violating line + * length restrictions, the methods will throw an exception to indicate this + * situation. + * + * In general, this code does not attempt to modify its input; for example, it + * does not attempt to change the case of any input characters, apply any + * Unicode normalization algorithms, or convert email addresses to ACE where + * applicable. The biggest exception to this rule is that most whitespace is + * collapsed to a single space, even in unstructured headers, while most leading + * and trailing whitespace is trimmed from inputs. + * + * @param {StreamHandler} handler The handler to which all output is sent. + * @param {Function(String)} handler.deliverData Receives encoded data. + * @param {Function()} handler.deliverEOF Sent when all text is sent. + * @param {Object} options Options for the emitter. + * @param [options.softMargin=78] {30 <= Integer <= 900} + * The ideal maximum number of logical characters to include in a line, not + * including the final CRLF pair. Lines may exceed this margin if parameters + * are excessively long. + * @param [options.hardMargin=332] {softMargin <= Integer <= 998} + * The maximum number of logical characters that can be included in a line, + * not including the final CRLF pair. If this count would be exceeded, then + * an error will be thrown and encoding will not be possible. + * @param [options.useASCII=true] {Boolean} + * If true, then RFC 2047 and RFC 2231 encoding of headers will be performed + * as needed to retain headers as ASCII. + */ +function HeaderEmitter(handler, options) { + /// The inferred value of options.useASCII + this._useASCII = options.useASCII === undefined ? true : options.useASCII; + /// The handler to use. + this._handler = handler; + /** + * The current line being built; note that we may insert a line break in the + * middle to keep under the maximum line length. + * + * @type String + * @private + */ + this._currentLine = ""; + + // Our bounds for soft and margins are not completely arbitrary. The minimum + // amount we need to encode is 20 characters, which can encode a single + // non-BMP character with RFC 2047. The value of 30 is chosen to give some + // breathing room for delimiters or other unbreakable characters. The maximum + // length is 998 octets, per RFC 5322; soft margins are slightly lower to + // allow for breathing room as well. The default of 78 for the soft margin is + // recommended by RFC 5322; the default of 332 for the hard margin ensures + // that UTF-8 encoding the output never violates the 998 octet limit. + this._softMargin = clamp(options.softMargin, 30, 900, 78); + this._hardMargin = clamp(options.hardMargin, this._softMargin, 998, 332); + + /** + * The index of the last preferred breakable position in the current line. + * + * @type Integer + * @private + */ + this._preferredBreakpoint = 0; +} + + +/////////////////////// +// Low-level methods // +/////////////////////// + +// Explanation of the emitter internals: +// RFC 5322 requires that we wrap our lines, ideally at 78 characters and at +// least by 998 octets. We can't wrap in arbitrary places, but wherever CFWS is +// valid... and ideally wherever clients are likely to expect it. In theory, we +// can break between every token (this is how RFC 822 operates), but, in RFC +// 5322, many of those breaks are relegated to obsolete productions, mostly +// because it is common to not properly handle breaks in those locations. +// +// So how do we do line breaking? The algorithm we implement is greedy, to +// simplify implementation. There are two margins: the soft margin, which we +// want to keep within, and the hard margin, which we absolutely have to keep +// within. There are also two kinds of break points: preferred and emergency. +// As long as we keep the line within the hard margin, we will only break at +// preferred breakpoints; emergency breakpoints are only used if we would +// otherwise exceed the hard margin. +// +// For illustration, here is an example header and where these break points are +// located: +// +// To: John "The Rock" Smith <jsmith@a.long.domain.invalid> +// Preferred: ^ ^ ^ +// Emergency: ^ ^ ^ ^^ ^ ^ ^ ^ ^ +// +// Preferred breakpoints are indicated by setting the mayBreakAfter parameter of +// addText to true, while emergency breakpoints are set after every token passed +// into addText. This is handled implicitly by only adding text to _currentLine +// if it ends in an emergency breakpoint. +// +// Internally, the code keeps track of margins by use of two variables. The +// _softMargin and _hardMargin variables encode the positions at which code must +// absolutely break, and are set up from the initial options parameter. Breaking +// happens when _currentLine.length approaches these values, as mentioned above. + +/** + * Send a header line consisting of the first N characters to the handler. + * + * If the count parameter is missing, then we presume that the current header + * value being emitted is done and therefore we should not send a continuation + * space. Otherwise, we presume that we're still working, so we will send the + * continuation space. + * + * @private + * @param [count] {Integer} The number of characters in the current line to + * include before wrapping. + */ +HeaderEmitter.prototype._commitLine = function (count) { + let isContinuing = typeof count !== "undefined"; + + // Split at the point, and lop off whitespace immediately before and after. + if (isContinuing) { + var firstN = this._currentLine.slice(0, count).trimRight(); + var lastN = this._currentLine.slice(count).trimLeft(); + } else { + var firstN = this._currentLine.trimRight(); + var lastN = ""; + } + + // How many characters do we need to shift preferred/emergency breakpoints? + let shift = this._currentLine.length - lastN.length; + + // Send the line plus the final CRLF. + this._handler.deliverData(firstN + '\r\n'); + + // Fill the start of the line with the new data. + this._currentLine = lastN; + + // If this is a continuation, add an extra space at the beginning of the line. + // Adjust the breakpoint shift amount as well. + if (isContinuing) { + this._currentLine = ' ' + this._currentLine; + shift++; + } + + // We will always break at a point at or after the _preferredBreakpoint, if it + // exists, so this always gets reset to 0. + this._preferredBreakpoint = 0; +}; + +/** + * Reserve at least length characters in the current line. If there aren't + * enough characters, insert a line break. + * + * @private + * @param length {Integer} The number of characters to reserve space for. + * @return {Boolean} Whether or not there is enough space for length characters. + */ +HeaderEmitter.prototype._reserveTokenSpace = function (length) { + // We are not going to do a sanity check that length is within the wrap + // margins. The rationale is that this lets code simply call this function to + // force a higher-level line break than normal preferred line breaks (see + // addAddress for an example use). The text that would be added may need to be + // itself broken up, so it might not need all the length anyways, but it + // starts the break already. + + // If we have enough space, we don't need to do anything. + if (this._currentLine.length + length <= this._softMargin) + return true; + + // If we have a preferred breakpoint, commit the line at that point, and see + // if that is sufficient line-breaking. + if (this._preferredBreakpoint > 0) { + this._commitLine(this._preferredBreakpoint); + if (this._currentLine.length + length <= this._softMargin) + return true; + } + + // At this point, we can no longer keep within the soft margin. Let us see if + // we can fit within the hard margin. + if (this._currentLine.length + length <= this._hardMargin) { + return true; + } + + // Adding the text to length would violate the hard margin as well. Break at + // the last emergency breakpoint. + if (this._currentLine.length > 0) { + this._commitLine(this._currentLine.length); + } + + // At this point, if there is still insufficient room in the hard margin, we + // can no longer do anything to encode this word. Bail. + return this._currentLine.length + length <= this._hardMargin; +}; + +/** + * Adds a block of text to the current header, inserting a break if necessary. + * If mayBreakAfter is true and text does not end in whitespace, a single space + * character may be added to the output. If the text could not be added without + * violating line length restrictions, an error is thrown instead. + * + * @protected + * @param {String} text The text to add to the output. + * @param {Boolean} mayBreakAfter If true, the end of this text is a preferred + * breakpoint. + */ +HeaderEmitter.prototype.addText = function (text, mayBreakAfter) { + // Try to reserve space for the tokens. If we can't, give up. + if (!this._reserveTokenSpace(text.length)) + throw new Error("Cannot encode " + text + " due to length."); + + this._currentLine += text; + if (mayBreakAfter) { + // Make sure that there is an extra space if text could break afterwards. + this._preferredBreakpoint = this._currentLine.length; + if (text[text.length - 1] != ' ') { + this._currentLine += ' '; + } + } +}; + +/** + * Adds a block of text that may need quoting if it contains some character in + * qchars. If it is already quoted, no quoting will be applied. If the text + * cannot be added without violating maximum line length, an error is thrown + * instead. + * + * @protected + * @param {String} text The text to add to the output. + * @param {String} qchars The set of characters that cannot appear + * outside of a quoted string. + * @param {Boolean} mayBreakAfter If true, the end of this text is a preferred + * breakpoint. + */ +HeaderEmitter.prototype.addQuotable = function (text, qchars, mayBreakAfter) { + // No text -> no need to be quoted (prevents strict warning errors). + if (text.length == 0) + return; + + // Figure out if we need to quote the string. Don't quote a string which + // already appears to be quoted. + let needsQuote = false; + + if (!(text[0] == '"' && text[text.length - 1] == '"') && qchars != '') { + for (let i = 0; i < text.length; i++) { + if (qchars.includes(text[i])) { + needsQuote = true; + break; + } + } + } + + if (needsQuote) + text = '"' + text.replace(/["\\]/g, "\\$&") + '"'; + this.addText(text, mayBreakAfter); +}; + +/** + * Adds a block of text that corresponds to the phrase production in RFC 5322. + * Such text is a sequence of atoms, quoted-strings, or RFC-2047 encoded-words. + * This method will preprocess input to normalize all space sequences to a + * single space. If the text cannot be added without violating maximum line + * length, an error is thrown instead. + * + * @protected + * @param {String} text The text to add to the output. + * @param {String} qchars The set of characters that cannot appear + * outside of a quoted string. + * @param {Boolean} mayBreakAfter If true, the end of this text is a preferred + * breakpoint. + */ +HeaderEmitter.prototype.addPhrase = function (text, qchars, mayBreakAfter) { + // Collapse all whitespace spans into a single whitespace node. + text = text.replace(/[ \t\r\n]+/g, " "); + + // If we have non-ASCII text, encode it using RFC 2047. + if (this._useASCII && nonAsciiRe.test(text)) { + this.encodeRFC2047Phrase(text, mayBreakAfter); + return; + } + + // If quoting the entire string at once could fit in the line length, then do + // so. The check here is very loose, but this will inform is if we are going + // to definitely overrun the soft margin. + if ((this._currentLine.length + text.length) < this._softMargin) { + try { + this.addQuotable(text, qchars, mayBreakAfter); + // If we don't have a breakpoint, and the text is encoded as a sequence of + // atoms (and not a quoted-string), then make the last space we added a + // breakpoint, regardless of the mayBreakAfter setting. + if (this._preferredBreakpoint == 0 && text.includes(" ")) { + if (this._currentLine[this._currentLine.length - 1] != '"') + this._preferredBreakpoint = this._currentLine.lastIndexOf(" "); + } + return; + } catch (e) { + // If we get an error at this point, we failed to add the quoted string + // because the string was too long. Fall through to the case where we know + // that the input was too long to begin with. + } + } + + // If the text is too long, split the quotable string at space boundaries and + // add each word invidually. If we still can't add all those words, there is + // nothing that we can do. + let words = text.split(' '); + for (let i = 0; i < words.length; i++) { + this.addQuotable(words[i], qchars, + i == words.length - 1 ? mayBreakAfter : true); + } +}; + +/// A regular expression for characters that need to be encoded. +var nonAsciiRe = /[^\x20-\x7e]/; + +/// The beginnings of RFC 2047 encoded-word +var b64Prelude = "=?UTF-8?B?", qpPrelude = "=?UTF-8?Q?"; + +/// A list of ASCII characters forbidden in RFC 2047 encoded-words +var qpForbidden = "=?_()\","; + +var hexString = "0123456789abcdef"; + +/** + * Add a block of text as a single RFC 2047 encoded word. This does not try to + * split words if they are too long. + * + * @private + * @param {Uint8Array} encodedText The octets to encode. + * @param {Boolean} useQP If true, use quoted-printable; if false, + * use base64. + * @param {Boolean} mayBreakAfter If true, the end of this text is a + * preferred breakpoint. + */ +HeaderEmitter.prototype._addRFC2047Word = function (encodedText, useQP, + mayBreakAfter) { + let binaryString = mimeutils.typedArrayToString(encodedText); + if (useQP) { + var token = qpPrelude; + for (let i = 0; i < encodedText.length; i++) { + if (encodedText[i] < 0x20 || encodedText[i] >= 0x7F || + qpForbidden.includes(binaryString[i])) { + let ch = encodedText[i]; + token += "=" + hexString[(ch & 0xf0) >> 4] + hexString[ch & 0x0f]; + } else if (binaryString[i] == " ") { + token += "_"; + } else { + token += binaryString[i]; + } + } + token += "?="; + } else { + var token = b64Prelude + btoa(binaryString) + "?="; + } + this.addText(token, mayBreakAfter); +}; + +/** + * Add a block of text as potentially several RFC 2047 encoded-word tokens. + * + * @protected + * @param {String} text The text to add to the output. + * @param {Boolean} mayBreakAfter If true, the end of this text is a preferred + * breakpoint. + */ +HeaderEmitter.prototype.encodeRFC2047Phrase = function (text, mayBreakAfter) { + // Start by encoding the text into UTF-8 directly. + let encodedText = new TextEncoder("UTF-8").encode(text); + + // Make sure there's enough room for a single token. + let minLineLen = b64Prelude.length + 10; // Eight base64 characters plus ?= + if (!this._reserveTokenSpace(minLineLen)) { + this._commitLine(this._currentLine.length); + } + + // Try to encode as much UTF-8 text as possible in each go. + let b64Len = 0, qpLen = 0, start = 0; + let maxChars = (this._softMargin - this._currentLine.length) - + (b64Prelude.length + 2); + for (let i = 0; i < encodedText.length; i++) { + let b64Inc = 0, qpInc = 0; + // The length we need for base64 is ceil(length / 3) * 4... + if ((i - start) % 3 == 0) + b64Inc += 4; + + // The length for quoted-printable is 3 chars only if encoded + if (encodedText[i] < 0x20 || encodedText[i] >= 0x7f || + qpForbidden.includes(String.fromCharCode(encodedText[i]))) { + qpInc = 3; + } else { + qpInc = 1; + } + + if (b64Len + b64Inc > maxChars && qpLen + qpInc > maxChars) { + // Oops, we have too many characters! We need to encode everything through + // the current character. However, we can't split in the middle of a + // multibyte character. In UTF-8, characters that start with 10xx xxxx are + // the middle of multibyte characters, so backtrack until the start + // character is legal. + while ((encodedText[i] & 0xC0) == 0x80) + --i; + + // Add this part of the word and then make a continuation. + this._addRFC2047Word(encodedText.subarray(start, i), b64Len >= qpLen, + true); + + // Reset the array for parsing. + start = i; + --i; // Reparse this character as well + b64Len = qpLen = 0; + maxChars = this._softMargin - b64Prelude.length - 3; + } else { + // Add the counts for the current variable to the count to encode. + b64Len += b64Inc; + qpLen += qpInc; + } + } + + // Add the entire array at this point. + this._addRFC2047Word(encodedText.subarray(start), b64Len >= qpLen, + mayBreakAfter); +}; + +//////////////////////// +// High-level methods // +//////////////////////// + +/** + * Add the header name, with the colon and trailing space, to the output. + * + * @public + * @param {String} name The name of the header. + */ +HeaderEmitter.prototype.addHeaderName = function (name) { + this._currentLine = this._currentLine.trimRight(); + if (this._currentLine.length > 0) { + this._commitLine(); + } + this.addText(name + ": ", false); +}; + +/** + * Add a header and its structured value to the output. + * + * The name can be any case-insensitive variant of a known structured header; + * the output will include the preferred name of the structure instead of the + * case put into the name. If no structured encoder can be found, and the input + * value is a string, then the header is assumed to be unstructured and the + * value is added as if {@link addUnstructured} were called. + * + * @public + * @param {String} name The name of the header. + * @param value The structured value of the header. + */ +HeaderEmitter.prototype.addStructuredHeader = function (name, value) { + let lowerName = name.toLowerCase(); + if (encoders.has(lowerName)) { + this.addHeaderName(preferredSpellings.get(lowerName)); + encoders.get(lowerName).call(this, value); + } else if (typeof value === "string") { + // Assume it's an unstructured header. + // All-lower-case-names are ugly, so capitalize first letters. + name = name.replace(/(^|-)[a-z]/g, function(match) { + return match.toUpperCase(); + }); + this.addHeaderName(name); + this.addUnstructured(value); + } else { + throw new Error("Unknown header " + name); + } +}; + +/** + * Add a single address to the header. The address is an object consisting of a + * possibly-empty display name and an email address. + * + * @public + * @param Address addr The address to be added. + * @param {String} addr.name The (possibly-empty) name of the address to add. + * @param {String} addr.email The email of the address to add. + * @see headerparser.parseAddressingHeader + */ +HeaderEmitter.prototype.addAddress = function (addr) { + // If we have a display name, add that first. + if (addr.name) { + // This is a simple estimate that keeps names on one line if possible. + this._reserveTokenSpace(addr.name.length + addr.email.length + 3); + this.addPhrase(addr.name, ",()<>[]:;@.\"", true); + + // If we don't have an email address, don't write out the angle brackets for + // the address. It's already an abnormal situation should this appear, and + // this has better round-tripping properties. + if (!addr.email) + return; + + this.addText("<", false); + } + + // Find the local-part and domain of the address, since the local-part may + // need to be quoted separately. Note that the @ goes to the domain, so that + // the local-part may be quoted if it needs to be. + let at = addr.email.lastIndexOf("@"); + let localpart = "", domain = "" + if (at == -1) + localpart = addr.email; + else { + localpart = addr.email.slice(0, at); + domain = addr.email.slice(at); + } + + this.addQuotable(localpart, "()<>[]:;@\\,\" !", false); + this.addText(domain + (addr.name ? ">" : ""), false); +}; + +/** + * Add an array of addresses and groups to the output. Such an array may be + * found as the output of {@link headerparser.parseAddressingHeader}. Each + * element is either an address (an object with properties name and email), or a + * group (an object with properties name and group). + * + * @public + * @param {(Address|Group)[]} addrs A collection of addresses to add. + * @param {String} addrs[i].name The (possibly-empty) name of the + * address or the group to add. + * @param {String} [addrs[i].email] The email of the address to add. + * @param {Address[]} [addrs[i].group] A list of email addresses in the group. + * @see HeaderEmitter.addAddress + * @see headerparser.parseAddressingHeader + */ +HeaderEmitter.prototype.addAddresses = function (addresses) { + let needsComma = false; + for (let addr of addresses) { + // Add a comma if this is not the first element. + if (needsComma) + this.addText(", ", true); + needsComma = true; + + if ("email" in addr) { + this.addAddress(addr); + } else { + // A group has format name: member, member; + // Note that we still add a comma after the group is completed. + this.addPhrase(addr.name, ",()<>[]:;@.\"", false); + this.addText(":", true); + + this.addAddresses(addr.group); + this.addText(";", true); + } + } +}; + +/** + * Add an unstructured header value to the output. This effectively means only + * inserting line breaks were necessary, and using RFC 2047 encoding where + * necessary. + * + * @public + * @param {String} text The text to add to the output. + */ +HeaderEmitter.prototype.addUnstructured = function (text) { + if (text.length == 0) + return; + + // Unstructured text is basically a phrase that can't be quoted. So, if we + // have nothing in qchars, nothing should be quoted. + this.addPhrase(text, "", false); +}; + +/** RFC 822 labels for days of the week. */ +var kDaysOfWeek = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]; + +/** + * Formatting helper to output numbers between 0-9 as 00-09 instead. + */ +function padTo2Digits(num) { + return num < 10 ? "0" + num : num.toString(); +} + +/** + * Add a date/time field to the output, using the JS date object as the time + * representation. The value will be output using the timezone offset of the + * date object, which is usually the timezone of the user (modulo timezone and + * DST changes). + * + * Note that if the date is an invalid date (its internal date parameter is a + * NaN value), this method throws an error instead of generating an invalid + * string. + * + * @public + * @param {Date} date The date to be added to the output string. + */ +HeaderEmitter.prototype.addDate = function (date) { + // Rather than make a header plastered with NaN values, throw an error on + // specific invalid dates. + if (isNaN(date.getTime())) + throw new Error("Cannot encode an invalid date"); + + // RFC 5322 says years can't be before 1900. The after 9999 is a bit that + // derives from the specification saying that years have 4 digits. + if (date.getFullYear() < 1900 || date.getFullYear() > 9999) + throw new Error("Date year is out of encodable range"); + + // Start by computing the timezone offset for a day. We lack a good format, so + // the the 0-padding is done by hand. Note that the tzoffset we output is in + // the form ±hhmm, so we need to separate the offset (in minutes) into an hour + // and minute pair. + let tzOffset = date.getTimezoneOffset(); + let tzOffHours = Math.abs(Math.trunc(tzOffset / 60)); + let tzOffMinutes = Math.abs(tzOffset) % 60; + let tzOffsetStr = (tzOffset > 0 ? "-" : "+") + + padTo2Digits(tzOffHours) + padTo2Digits(tzOffMinutes); + + // Convert the day-time figure into a single value to avoid unwanted line + // breaks in the middle. + let dayTime = [ + kDaysOfWeek[date.getDay()] + ",", + date.getDate(), + mimeutils.kMonthNames[date.getMonth()], + date.getFullYear(), + padTo2Digits(date.getHours()) + ":" + + padTo2Digits(date.getMinutes()) + ":" + + padTo2Digits(date.getSeconds()), + tzOffsetStr + ].join(" "); + this.addText(dayTime, false); +}; + +/** + * Signal that the current header has been finished encoding. + * + * @public + * @param {Boolean} deliverEOF If true, signal to the handler that no more text + * will be arriving. + */ +HeaderEmitter.prototype.finish = function (deliverEOF) { + this._commitLine(); + if (deliverEOF) + this._handler.deliverEOF(); +}; + +/** + * Make a streaming header emitter that outputs on the given handler. + * + * @param {StreamHandler} handler The handler to consume output + * @param options Options to pass into the HeaderEmitter + * constructor. + * @returns {HeaderEmitter} A header emitter constructed with the given options. + */ +function makeStreamingEmitter(handler, options) { + return new HeaderEmitter(handler, options); +} + +function StringHandler() { + this.value = ""; + this.deliverData = function (str) { this.value += str; }; + this.deliverEOF = function () { }; +} + +/** + * Given a header name and its structured value, output a string containing its + * MIME-encoded value. The trailing CRLF for the header is included. + * + * @param {String} name The name of the structured header. + * @param value The value of the structured header. + * @param options Options for the HeaderEmitter constructor. + * @returns {String} A MIME-encoded representation of the structured header. + * @see HeaderEmitter.addStructuredHeader + */ +function emitStructuredHeader(name, value, options) { + let handler = new StringHandler(); + let emitter = new HeaderEmitter(handler, options); + emitter.addStructuredHeader(name, value); + emitter.finish(true); + return handler.value; +} + +/** + * Given a map of header names and their structured values, output a string + * containing all of their headers and their MIME-encoded values. + * + * This method is designed to be able to emit header values given the headerData + * values produced by MIME parsing. Thus, the values of the map are arrays + * corresponding to header multiplicity. + * + * @param {Map(String->Object[])} headerValues A map of header names to arrays + * of their structured values. + * @param options Options for the HeaderEmitter + * constructor. + * @returns {String} A MIME-encoded representation of the structured header. + * @see HeaderEmitter.addStructuredHeader + */ +function emitStructuredHeaders(headerValues, options) { + let handler = new StringHandler(); + let emitter = new HeaderEmitter(handler, options); + for (let instance of headerValues) { + instance[1].forEach(function (e) { + emitter.addStructuredHeader(instance[0], e) + }); + } + emitter.finish(true); + return handler.value; +} + +/** + * Add a custom structured MIME encoder to the set of known encoders. These + * encoders are used for {@link emitStructuredHeader} and similar functions to + * encode richer, more structured values instead of relying on string + * representations everywhere. + * + * Structured encoders are functions which take in a single parameter + * representing their structured value. The this parameter is set to be an + * instance of {@link HeaderEmitter}, and it is intended that the several public + * or protected methods on that class are useful for encoding values. + * + * There is a large set of structured encoders built-in to the jsmime library + * already. + * + * @param {String} header The header name (in its preferred case) for + * which the encoder will be used. + * @param {Function(Value)} encoder The structured encoder function. + */ +function addStructuredEncoder(header, encoder) { + let lowerName = header.toLowerCase(); + encoders.set(lowerName, encoder); + if (!preferredSpellings.has(lowerName)) + preferredSpellings.set(lowerName, header); +} + +return Object.freeze({ + addStructuredEncoder: addStructuredEncoder, + emitStructuredHeader: emitStructuredHeader, + emitStructuredHeaders: emitStructuredHeaders, + makeStreamingEmitter: makeStreamingEmitter +}); + +}); + +def('jsmime', function(require) { + return { + MimeParser: require('./mimeparser'), + headerparser: require('./headerparser'), + headeremitter: require('./headeremitter') + } +}); + return mods['jsmime']; +})); |