1 files changed, 414 insertions, 0 deletions
diff --git a/devtools/shared/transport/packets.js b/devtools/shared/transport/packets.js
new file mode 100644
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+++ b/devtools/shared/transport/packets.js
@@ -0,0 +1,414 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+/**
+ * Packets contain read / write functionality for the different packet types
+ * supported by the debugging protocol, so that a transport can focus on
+ * delivery and queue management without worrying too much about the specific
+ * packet types.
+ *
+ * They are intended to be "one use only", so a new packet should be
+ * instantiated for each incoming or outgoing packet.
+ *
+ * A complete Packet type should expose at least the following:
+ *   * read(stream, scriptableStream)
+ *     Called when the input stream has data to read
+ *   * write(stream)
+ *     Called when the output stream is ready to write
+ *   * get done()
+ *     Returns true once the packet is done being read / written
+ *   * destroy()
+ *     Called to clean up at the end of use
+ */
+
+const { Cc, Ci, Cu } = require("chrome");
+const DevToolsUtils = require("devtools/shared/DevToolsUtils");
+const { dumpn, dumpv } = DevToolsUtils;
+const flags = require("devtools/shared/flags");
+const StreamUtils = require("devtools/shared/transport/stream-utils");
+const promise = require("promise");
+const defer = require("devtools/shared/defer");
+
+DevToolsUtils.defineLazyGetter(this, "unicodeConverter", () => {
+  const unicodeConverter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
+                           .createInstance(Ci.nsIScriptableUnicodeConverter);
+  unicodeConverter.charset = "UTF-8";
+  return unicodeConverter;
+});
+
+// The transport's previous check ensured the header length did not exceed 20
+// characters.  Here, we opt for the somewhat smaller, but still large limit of
+// 1 TiB.
+const PACKET_LENGTH_MAX = Math.pow(2, 40);
+
+/**
+ * A generic Packet processing object (extended by two subtypes below).
+ */
+function Packet(transport) {
+  this._transport = transport;
+  this._length = 0;
+}
+
+/**
+ * Attempt to initialize a new Packet based on the incoming packet header we've
+ * received so far.  We try each of the types in succession, trying JSON packets
+ * first since they are much more common.
+ * @param header string
+ *        The packet header string to attempt parsing.
+ * @param transport DebuggerTransport
+ *        The transport instance that will own the packet.
+ * @return Packet
+ *         The parsed packet of the matching type, or null if no types matched.
+ */
+Packet.fromHeader = function (header, transport) {
+  return JSONPacket.fromHeader(header, transport) ||
+         BulkPacket.fromHeader(header, transport);
+};
+
+Packet.prototype = {
+
+  get length() {
+    return this._length;
+  },
+
+  set length(length) {
+    if (length > PACKET_LENGTH_MAX) {
+      throw Error("Packet length " + length + " exceeds the max length of " +
+                  PACKET_LENGTH_MAX);
+    }
+    this._length = length;
+  },
+
+  destroy: function () {
+    this._transport = null;
+  }
+
+};
+
+exports.Packet = Packet;
+
+/**
+ * With a JSON packet (the typical packet type sent via the transport), data is
+ * transferred as a JSON packet serialized into a string, with the string length
+ * prepended to the packet, followed by a colon ([length]:[packet]). The
+ * contents of the JSON packet are specified in the Remote Debugging Protocol
+ * specification.
+ * @param transport DebuggerTransport
+ *        The transport instance that will own the packet.
+ */
+function JSONPacket(transport) {
+  Packet.call(this, transport);
+  this._data = "";
+  this._done = false;
+}
+
+/**
+ * Attempt to initialize a new JSONPacket based on the incoming packet header
+ * we've received so far.
+ * @param header string
+ *        The packet header string to attempt parsing.
+ * @param transport DebuggerTransport
+ *        The transport instance that will own the packet.
+ * @return JSONPacket
+ *         The parsed packet, or null if it's not a match.
+ */
+JSONPacket.fromHeader = function (header, transport) {
+  let match = this.HEADER_PATTERN.exec(header);
+
+  if (!match) {
+    return null;
+  }
+
+  dumpv("Header matches JSON packet");
+  let packet = new JSONPacket(transport);
+  packet.length = +match[1];
+  return packet;
+};
+
+JSONPacket.HEADER_PATTERN = /^(\d+):$/;
+
+JSONPacket.prototype = Object.create(Packet.prototype);
+
+Object.defineProperty(JSONPacket.prototype, "object", {
+  /**
+   * Gets the object (not the serialized string) being read or written.
+   */
+  get: function () { return this._object; },
+
+  /**
+   * Sets the object to be sent when write() is called.
+   */
+  set: function (object) {
+    this._object = object;
+    let data = JSON.stringify(object);
+    this._data = unicodeConverter.ConvertFromUnicode(data);
+    this.length = this._data.length;
+  }
+});
+
+JSONPacket.prototype.read = function (stream, scriptableStream) {
+  dumpv("Reading JSON packet");
+
+  // Read in more packet data.
+  this._readData(stream, scriptableStream);
+
+  if (!this.done) {
+    // Don't have a complete packet yet.
+    return;
+  }
+
+  let json = this._data;
+  try {
+    json = unicodeConverter.ConvertToUnicode(json);
+    this._object = JSON.parse(json);
+  } catch (e) {
+    let msg = "Error parsing incoming packet: " + json + " (" + e +
+              " - " + e.stack + ")";
+    console.error(msg);
+    dumpn(msg);
+    return;
+  }
+
+  this._transport._onJSONObjectReady(this._object);
+};
+
+JSONPacket.prototype._readData = function (stream, scriptableStream) {
+  if (flags.wantVerbose) {
+    dumpv("Reading JSON data: _l: " + this.length + " dL: " +
+          this._data.length + " sA: " + stream.available());
+  }
+  let bytesToRead = Math.min(this.length - this._data.length,
+                             stream.available());
+  this._data += scriptableStream.readBytes(bytesToRead);
+  this._done = this._data.length === this.length;
+};
+
+JSONPacket.prototype.write = function (stream) {
+  dumpv("Writing JSON packet");
+
+  if (this._outgoing === undefined) {
+    // Format the serialized packet to a buffer
+    this._outgoing = this.length + ":" + this._data;
+  }
+
+  let written = stream.write(this._outgoing, this._outgoing.length);
+  this._outgoing = this._outgoing.slice(written);
+  this._done = !this._outgoing.length;
+};
+
+Object.defineProperty(JSONPacket.prototype, "done", {
+  get: function () { return this._done; }
+});
+
+JSONPacket.prototype.toString = function () {
+  return JSON.stringify(this._object, null, 2);
+};
+
+exports.JSONPacket = JSONPacket;
+
+/**
+ * With a bulk packet, data is transferred by temporarily handing over the
+ * transport's input or output stream to the application layer for writing data
+ * directly.  This can be much faster for large data sets, and avoids various
+ * stages of copies and data duplication inherent in the JSON packet type.  The
+ * bulk packet looks like:
+ *
+ * bulk [actor] [type] [length]:[data]
+ *
+ * The interpretation of the data portion depends on the kind of actor and the
+ * packet's type.  See the Remote Debugging Protocol Stream Transport spec for
+ * more details.
+ * @param transport DebuggerTransport
+ *        The transport instance that will own the packet.
+ */
+function BulkPacket(transport) {
+  Packet.call(this, transport);
+  this._done = false;
+  this._readyForWriting = defer();
+}
+
+/**
+ * Attempt to initialize a new BulkPacket based on the incoming packet header
+ * we've received so far.
+ * @param header string
+ *        The packet header string to attempt parsing.
+ * @param transport DebuggerTransport
+ *        The transport instance that will own the packet.
+ * @return BulkPacket
+ *         The parsed packet, or null if it's not a match.
+ */
+BulkPacket.fromHeader = function (header, transport) {
+  let match = this.HEADER_PATTERN.exec(header);
+
+  if (!match) {
+    return null;
+  }
+
+  dumpv("Header matches bulk packet");
+  let packet = new BulkPacket(transport);
+  packet.header = {
+    actor: match[1],
+    type: match[2],
+    length: +match[3]
+  };
+  return packet;
+};
+
+BulkPacket.HEADER_PATTERN = /^bulk ([^: ]+) ([^: ]+) (\d+):$/;
+
+BulkPacket.prototype = Object.create(Packet.prototype);
+
+BulkPacket.prototype.read = function (stream) {
+  dumpv("Reading bulk packet, handing off input stream");
+
+  // Temporarily pause monitoring of the input stream
+  this._transport.pauseIncoming();
+
+  let deferred = defer();
+
+  this._transport._onBulkReadReady({
+    actor: this.actor,
+    type: this.type,
+    length: this.length,
+    copyTo: (output) => {
+      dumpv("CT length: " + this.length);
+      let copying = StreamUtils.copyStream(stream, output, this.length);
+      deferred.resolve(copying);
+      return copying;
+    },
+    stream: stream,
+    done: deferred
+  });
+
+  // Await the result of reading from the stream
+  deferred.promise.then(() => {
+    dumpv("onReadDone called, ending bulk mode");
+    this._done = true;
+    this._transport.resumeIncoming();
+  }, this._transport.close);
+
+  // Ensure this is only done once
+  this.read = () => {
+    throw new Error("Tried to read() a BulkPacket's stream multiple times.");
+  };
+};
+
+BulkPacket.prototype.write = function (stream) {
+  dumpv("Writing bulk packet");
+
+  if (this._outgoingHeader === undefined) {
+    dumpv("Serializing bulk packet header");
+    // Format the serialized packet header to a buffer
+    this._outgoingHeader = "bulk " + this.actor + " " + this.type + " " +
+                           this.length + ":";
+  }
+
+  // Write the header, or whatever's left of it to write.
+  if (this._outgoingHeader.length) {
+    dumpv("Writing bulk packet header");
+    let written = stream.write(this._outgoingHeader,
+                               this._outgoingHeader.length);
+    this._outgoingHeader = this._outgoingHeader.slice(written);
+    return;
+  }
+
+  dumpv("Handing off output stream");
+
+  // Temporarily pause the monitoring of the output stream
+  this._transport.pauseOutgoing();
+
+  let deferred = defer();
+
+  this._readyForWriting.resolve({
+    copyFrom: (input) => {
+      dumpv("CF length: " + this.length);
+      let copying = StreamUtils.copyStream(input, stream, this.length);
+      deferred.resolve(copying);
+      return copying;
+    },
+    stream: stream,
+    done: deferred
+  });
+
+  // Await the result of writing to the stream
+  deferred.promise.then(() => {
+    dumpv("onWriteDone called, ending bulk mode");
+    this._done = true;
+    this._transport.resumeOutgoing();
+  }, this._transport.close);
+
+  // Ensure this is only done once
+  this.write = () => {
+    throw new Error("Tried to write() a BulkPacket's stream multiple times.");
+  };
+};
+
+Object.defineProperty(BulkPacket.prototype, "streamReadyForWriting", {
+  get: function () {
+    return this._readyForWriting.promise;
+  }
+});
+
+Object.defineProperty(BulkPacket.prototype, "header", {
+  get: function () {
+    return {
+      actor: this.actor,
+      type: this.type,
+      length: this.length
+    };
+  },
+
+  set: function (header) {
+    this.actor = header.actor;
+    this.type = header.type;
+    this.length = header.length;
+  },
+});
+
+Object.defineProperty(BulkPacket.prototype, "done", {
+  get: function () { return this._done; },
+});
+
+
+BulkPacket.prototype.toString = function () {
+  return "Bulk: " + JSON.stringify(this.header, null, 2);
+};
+
+exports.BulkPacket = BulkPacket;
+
+/**
+ * RawPacket is used to test the transport's error handling of malformed
+ * packets, by writing data directly onto the stream.
+ * @param transport DebuggerTransport
+ *        The transport instance that will own the packet.
+ * @param data string
+ *        The raw string to send out onto the stream.
+ */
+function RawPacket(transport, data) {
+  Packet.call(this, transport);
+  this._data = data;
+  this.length = data.length;
+  this._done = false;
+}
+
+RawPacket.prototype = Object.create(Packet.prototype);
+
+RawPacket.prototype.read = function (stream) {
+  // This hasn't yet been needed for testing.
+  throw Error("Not implmented.");
+};
+
+RawPacket.prototype.write = function (stream) {
+  let written = stream.write(this._data, this._data.length);
+  this._data = this._data.slice(written);
+  this._done = !this._data.length;
+};
+
+Object.defineProperty(RawPacket.prototype, "done", {
+  get: function () { return this._done; }
+});
+
+exports.RawPacket = RawPacket;