1 files changed, 538 insertions, 0 deletions
diff --git a/devtools/shared/webconsole/js-property-provider.js b/devtools/shared/webconsole/js-property-provider.js
new file mode 100644
index 000000000..9ada46732
--- /dev/null
+++ b/devtools/shared/webconsole/js-property-provider.js
@@ -0,0 +1,538 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ft= javascript ts=2 et sw=2 tw=80: */
+/* 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";
+
+const DevToolsUtils = require("devtools/shared/DevToolsUtils");
+
+if (!isWorker) {
+  loader.lazyImporter(this, "Parser", "resource://devtools/shared/Parser.jsm");
+}
+
+// Provide an easy way to bail out of even attempting an autocompletion
+// if an object has way too many properties. Protects against large objects
+// with numeric values that wouldn't be tallied towards MAX_AUTOCOMPLETIONS.
+const MAX_AUTOCOMPLETE_ATTEMPTS = exports.MAX_AUTOCOMPLETE_ATTEMPTS = 100000;
+// Prevent iterating over too many properties during autocomplete suggestions.
+const MAX_AUTOCOMPLETIONS = exports.MAX_AUTOCOMPLETIONS = 1500;
+
+const STATE_NORMAL = 0;
+const STATE_QUOTE = 2;
+const STATE_DQUOTE = 3;
+
+const OPEN_BODY = "{[(".split("");
+const CLOSE_BODY = "}])".split("");
+const OPEN_CLOSE_BODY = {
+  "{": "}",
+  "[": "]",
+  "(": ")",
+};
+
+function hasArrayIndex(str) {
+  return /\[\d+\]$/.test(str);
+}
+
+/**
+ * Analyses a given string to find the last statement that is interesting for
+ * later completion.
+ *
+ * @param   string str
+ *          A string to analyse.
+ *
+ * @returns object
+ *          If there was an error in the string detected, then a object like
+ *
+ *            { err: "ErrorMesssage" }
+ *
+ *          is returned, otherwise a object like
+ *
+ *            {
+ *              state: STATE_NORMAL|STATE_QUOTE|STATE_DQUOTE,
+ *              startPos: index of where the last statement begins
+ *            }
+ */
+function findCompletionBeginning(str) {
+  let bodyStack = [];
+
+  let state = STATE_NORMAL;
+  let start = 0;
+  let c;
+  for (let i = 0; i < str.length; i++) {
+    c = str[i];
+
+    switch (state) {
+      // Normal JS state.
+      case STATE_NORMAL:
+        if (c == '"') {
+          state = STATE_DQUOTE;
+        } else if (c == "'") {
+          state = STATE_QUOTE;
+        } else if (c == ";") {
+          start = i + 1;
+        } else if (c == " ") {
+          start = i + 1;
+        } else if (OPEN_BODY.indexOf(c) != -1) {
+          bodyStack.push({
+            token: c,
+            start: start
+          });
+          start = i + 1;
+        } else if (CLOSE_BODY.indexOf(c) != -1) {
+          let last = bodyStack.pop();
+          if (!last || OPEN_CLOSE_BODY[last.token] != c) {
+            return {
+              err: "syntax error"
+            };
+          }
+          if (c == "}") {
+            start = i + 1;
+          } else {
+            start = last.start;
+          }
+        }
+        break;
+
+      // Double quote state > " <
+      case STATE_DQUOTE:
+        if (c == "\\") {
+          i++;
+        } else if (c == "\n") {
+          return {
+            err: "unterminated string literal"
+          };
+        } else if (c == '"') {
+          state = STATE_NORMAL;
+        }
+        break;
+
+      // Single quote state > ' <
+      case STATE_QUOTE:
+        if (c == "\\") {
+          i++;
+        } else if (c == "\n") {
+          return {
+            err: "unterminated string literal"
+          };
+        } else if (c == "'") {
+          state = STATE_NORMAL;
+        }
+        break;
+    }
+  }
+
+  return {
+    state: state,
+    startPos: start
+  };
+}
+
+/**
+ * Provides a list of properties, that are possible matches based on the passed
+ * Debugger.Environment/Debugger.Object and inputValue.
+ *
+ * @param object dbgObject
+ *        When the debugger is not paused this Debugger.Object wraps
+ *        the scope for autocompletion.
+ *        It is null if the debugger is paused.
+ * @param object anEnvironment
+ *        When the debugger is paused this Debugger.Environment is the
+ *        scope for autocompletion.
+ *        It is null if the debugger is not paused.
+ * @param string inputValue
+ *        Value that should be completed.
+ * @param number [cursor=inputValue.length]
+ *        Optional offset in the input where the cursor is located. If this is
+ *        omitted then the cursor is assumed to be at the end of the input
+ *        value.
+ * @returns null or object
+ *          If no completion valued could be computed, null is returned,
+ *          otherwise a object with the following form is returned:
+ *            {
+ *              matches: [ string, string, string ],
+ *              matchProp: Last part of the inputValue that was used to find
+ *                         the matches-strings.
+ *            }
+ */
+function JSPropertyProvider(dbgObject, anEnvironment, inputValue, cursor) {
+  if (cursor === undefined) {
+    cursor = inputValue.length;
+  }
+
+  inputValue = inputValue.substring(0, cursor);
+
+  // Analyse the inputValue and find the beginning of the last part that
+  // should be completed.
+  let beginning = findCompletionBeginning(inputValue);
+
+  // There was an error analysing the string.
+  if (beginning.err) {
+    return null;
+  }
+
+  // If the current state is not STATE_NORMAL, then we are inside of an string
+  // which means that no completion is possible.
+  if (beginning.state != STATE_NORMAL) {
+    return null;
+  }
+
+  let completionPart = inputValue.substring(beginning.startPos);
+  let lastDot = completionPart.lastIndexOf(".");
+
+  // Don't complete on just an empty string.
+  if (completionPart.trim() == "") {
+    return null;
+  }
+
+  // Catch literals like [1,2,3] or "foo" and return the matches from
+  // their prototypes.
+  // Don't run this is a worker, migrating to acorn should allow this
+  // to run in a worker - Bug 1217198.
+  if (!isWorker && lastDot > 0) {
+    let parser = new Parser();
+    parser.logExceptions = false;
+    let syntaxTree = parser.get(completionPart.slice(0, lastDot));
+    let lastTree = syntaxTree.getLastSyntaxTree();
+    let lastBody = lastTree && lastTree.AST.body[lastTree.AST.body.length - 1];
+
+    // Finding the last expression since we've sliced up until the dot.
+    // If there were parse errors this won't exist.
+    if (lastBody) {
+      let expression = lastBody.expression;
+      let matchProp = completionPart.slice(lastDot + 1);
+      if (expression.type === "ArrayExpression") {
+        return getMatchedProps(Array.prototype, matchProp);
+      } else if (expression.type === "Literal" &&
+                 (typeof expression.value === "string")) {
+        return getMatchedProps(String.prototype, matchProp);
+      }
+    }
+  }
+
+  // We are completing a variable / a property lookup.
+  let properties = completionPart.split(".");
+  let matchProp = properties.pop().trimLeft();
+  let obj = dbgObject;
+
+  // The first property must be found in the environment of the paused debugger
+  // or of the global lexical scope.
+  let env = anEnvironment || obj.asEnvironment();
+
+  if (properties.length === 0) {
+    return getMatchedPropsInEnvironment(env, matchProp);
+  }
+
+  let firstProp = properties.shift().trim();
+  if (firstProp === "this") {
+    // Special case for 'this' - try to get the Object from the Environment.
+    // No problem if it throws, we will just not autocomplete.
+    try {
+      obj = env.object;
+    } catch (e) {
+      // Ignore.
+    }
+  } else if (hasArrayIndex(firstProp)) {
+    obj = getArrayMemberProperty(null, env, firstProp);
+  } else {
+    obj = getVariableInEnvironment(env, firstProp);
+  }
+
+  if (!isObjectUsable(obj)) {
+    return null;
+  }
+
+  // We get the rest of the properties recursively starting from the
+  // Debugger.Object that wraps the first property
+  for (let i = 0; i < properties.length; i++) {
+    let prop = properties[i].trim();
+    if (!prop) {
+      return null;
+    }
+
+    if (hasArrayIndex(prop)) {
+      // The property to autocomplete is a member of array. For example
+      // list[i][j]..[n]. Traverse the array to get the actual element.
+      obj = getArrayMemberProperty(obj, null, prop);
+    } else {
+      obj = DevToolsUtils.getProperty(obj, prop);
+    }
+
+    if (!isObjectUsable(obj)) {
+      return null;
+    }
+  }
+
+  // If the final property is a primitive
+  if (typeof obj != "object") {
+    return getMatchedProps(obj, matchProp);
+  }
+
+  return getMatchedPropsInDbgObject(obj, matchProp);
+}
+
+/**
+ * Get the array member of obj for the given prop. For example, given
+ * prop='list[0][1]' the element at [0][1] of obj.list is returned.
+ *
+ * @param object obj
+ *        The object to operate on. Should be null if env is passed.
+ * @param object env
+ *        The Environment to operate in. Should be null if obj is passed.
+ * @param string prop
+ *        The property to return.
+ * @return null or Object
+ *         Returns null if the property couldn't be located. Otherwise the array
+ *         member identified by prop.
+ */
+function getArrayMemberProperty(obj, env, prop) {
+  // First get the array.
+  let propWithoutIndices = prop.substr(0, prop.indexOf("["));
+
+  if (env) {
+    obj = getVariableInEnvironment(env, propWithoutIndices);
+  } else {
+    obj = DevToolsUtils.getProperty(obj, propWithoutIndices);
+  }
+
+  if (!isObjectUsable(obj)) {
+    return null;
+  }
+
+  // Then traverse the list of indices to get the actual element.
+  let result;
+  let arrayIndicesRegex = /\[[^\]]*\]/g;
+  while ((result = arrayIndicesRegex.exec(prop)) !== null) {
+    let indexWithBrackets = result[0];
+    let indexAsText = indexWithBrackets.substr(1, indexWithBrackets.length - 2);
+    let index = parseInt(indexAsText, 10);
+
+    if (isNaN(index)) {
+      return null;
+    }
+
+    obj = DevToolsUtils.getProperty(obj, index);
+
+    if (!isObjectUsable(obj)) {
+      return null;
+    }
+  }
+
+  return obj;
+}
+
+/**
+ * Check if the given Debugger.Object can be used for autocomplete.
+ *
+ * @param Debugger.Object object
+ *        The Debugger.Object to check.
+ * @return boolean
+ *         True if further inspection into the object is possible, or false
+ *         otherwise.
+ */
+function isObjectUsable(object) {
+  if (object == null) {
+    return false;
+  }
+
+  if (typeof object == "object" && object.class == "DeadObject") {
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * @see getExactMatchImpl()
+ */
+function getVariableInEnvironment(anEnvironment, name) {
+  return getExactMatchImpl(anEnvironment, name, DebuggerEnvironmentSupport);
+}
+
+/**
+ * @see getMatchedPropsImpl()
+ */
+function getMatchedPropsInEnvironment(anEnvironment, match) {
+  return getMatchedPropsImpl(anEnvironment, match, DebuggerEnvironmentSupport);
+}
+
+/**
+ * @see getMatchedPropsImpl()
+ */
+function getMatchedPropsInDbgObject(dbgObject, match) {
+  return getMatchedPropsImpl(dbgObject, match, DebuggerObjectSupport);
+}
+
+/**
+ * @see getMatchedPropsImpl()
+ */
+function getMatchedProps(obj, match) {
+  if (typeof obj != "object") {
+    obj = obj.constructor.prototype;
+  }
+  return getMatchedPropsImpl(obj, match, JSObjectSupport);
+}
+
+/**
+ * Get all properties in the given object (and its parent prototype chain) that
+ * match a given prefix.
+ *
+ * @param mixed obj
+ *        Object whose properties we want to filter.
+ * @param string match
+ *        Filter for properties that match this string.
+ * @return object
+ *         Object that contains the matchProp and the list of names.
+ */
+function getMatchedPropsImpl(obj, match, {chainIterator, getProperties}) {
+  let matches = new Set();
+  let numProps = 0;
+
+  // We need to go up the prototype chain.
+  let iter = chainIterator(obj);
+  for (obj of iter) {
+    let props = getProperties(obj);
+    numProps += props.length;
+
+    // If there are too many properties to event attempt autocompletion,
+    // or if we have already added the max number, then stop looping
+    // and return the partial set that has already been discovered.
+    if (numProps >= MAX_AUTOCOMPLETE_ATTEMPTS ||
+        matches.size >= MAX_AUTOCOMPLETIONS) {
+      break;
+    }
+
+    for (let i = 0; i < props.length; i++) {
+      let prop = props[i];
+      if (prop.indexOf(match) != 0) {
+        continue;
+      }
+      if (prop.indexOf("-") > -1) {
+        continue;
+      }
+      // If it is an array index, we can't take it.
+      // This uses a trick: converting a string to a number yields NaN if
+      // the operation failed, and NaN is not equal to itself.
+      if (+prop != +prop) {
+        matches.add(prop);
+      }
+
+      if (matches.size >= MAX_AUTOCOMPLETIONS) {
+        break;
+      }
+    }
+  }
+
+  return {
+    matchProp: match,
+    matches: [...matches],
+  };
+}
+
+/**
+ * Returns a property value based on its name from the given object, by
+ * recursively checking the object's prototype.
+ *
+ * @param object obj
+ *        An object to look the property into.
+ * @param string name
+ *        The property that is looked up.
+ * @returns object|undefined
+ *        A Debugger.Object if the property exists in the object's prototype
+ *        chain, undefined otherwise.
+ */
+function getExactMatchImpl(obj, name, {chainIterator, getProperty}) {
+  // We need to go up the prototype chain.
+  let iter = chainIterator(obj);
+  for (obj of iter) {
+    let prop = getProperty(obj, name, obj);
+    if (prop) {
+      return prop.value;
+    }
+  }
+  return undefined;
+}
+
+var JSObjectSupport = {
+  chainIterator: function* (obj) {
+    while (obj) {
+      yield obj;
+      obj = Object.getPrototypeOf(obj);
+    }
+  },
+
+  getProperties: function (obj) {
+    return Object.getOwnPropertyNames(obj);
+  },
+
+  getProperty: function () {
+    // getProperty is unsafe with raw JS objects.
+    throw new Error("Unimplemented!");
+  },
+};
+
+var DebuggerObjectSupport = {
+  chainIterator: function* (obj) {
+    while (obj) {
+      yield obj;
+      obj = obj.proto;
+    }
+  },
+
+  getProperties: function (obj) {
+    return obj.getOwnPropertyNames();
+  },
+
+  getProperty: function (obj, name, rootObj) {
+    // This is left unimplemented in favor to DevToolsUtils.getProperty().
+    throw new Error("Unimplemented!");
+  },
+};
+
+var DebuggerEnvironmentSupport = {
+  chainIterator: function* (obj) {
+    while (obj) {
+      yield obj;
+      obj = obj.parent;
+    }
+  },
+
+  getProperties: function (obj) {
+    let names = obj.names();
+
+    // Include 'this' in results (in sorted order)
+    for (let i = 0; i < names.length; i++) {
+      if (i === names.length - 1 || names[i + 1] > "this") {
+        names.splice(i + 1, 0, "this");
+        break;
+      }
+    }
+
+    return names;
+  },
+
+  getProperty: function (obj, name) {
+    let result;
+    // Try/catch since name can be anything, and getVariable throws if
+    // it's not a valid ECMAScript identifier name
+    try {
+      // TODO: we should use getVariableDescriptor() here - bug 725815.
+      result = obj.getVariable(name);
+    } catch (e) {
+      // Ignore.
+    }
+
+    // FIXME: Need actual UI, bug 941287.
+    if (result === undefined || result.optimizedOut ||
+        result.missingArguments) {
+      return null;
+    }
+    return { value: result };
+  },
+};
+
+exports.JSPropertyProvider = DevToolsUtils.makeInfallible(JSPropertyProvider);
+
+// Export a version that will throw (for tests)
+exports.FallibleJSPropertyProvider = JSPropertyProvider;