Bug 669999 - Add a library for parsing and consuming source map files to Firefox; r=joe_walker,rcampbell
authorNick Fitzgerald <fitzgen@gmail.com>
Wed, 18 Jul 2012 17:17:00 -0400
changeset 103118 6aac641e3d3822c8f2c2a516ba27e0d38c53c273
parent 103023 6d4904694feb194ce3f205667d83446ac96fc277
child 103119 1b756e58e59a72fa192e78e94d4fe1a8bbe5e7dc
push id1989
push userakeybl@mozilla.com
push dateTue, 28 Aug 2012 00:20:43 +0000
treeherdermozilla-aurora@a8e95ae10ea7 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersjoe_walker, rcampbell
bugs669999
milestone17.0a1
Bug 669999 - Add a library for parsing and consuming source map files to Firefox; r=joe_walker,rcampbell
testing/xpcshell/xpcshell.ini
toolkit/devtools/Makefile.in
toolkit/devtools/sourcemap/Makefile.in
toolkit/devtools/sourcemap/SourceMap.jsm
toolkit/devtools/sourcemap/tests/Makefile.in
toolkit/devtools/sourcemap/tests/unit/Utils.jsm
toolkit/devtools/sourcemap/tests/unit/head_sourcemap.js
toolkit/devtools/sourcemap/tests/unit/test_array_set.js
toolkit/devtools/sourcemap/tests/unit/test_base64.js
toolkit/devtools/sourcemap/tests/unit/test_base64_vlq.js
toolkit/devtools/sourcemap/tests/unit/test_binary_search.js
toolkit/devtools/sourcemap/tests/unit/test_dog_fooding.js
toolkit/devtools/sourcemap/tests/unit/test_source_map_consumer.js
toolkit/devtools/sourcemap/tests/unit/test_source_map_generator.js
toolkit/devtools/sourcemap/tests/unit/test_source_node.js
toolkit/devtools/sourcemap/tests/unit/xpcshell.ini
--- a/testing/xpcshell/xpcshell.ini
+++ b/testing/xpcshell/xpcshell.ini
@@ -18,16 +18,17 @@
 [include:dom/indexedDB/test/unit/xpcshell.ini]
 [include:content/xtf/test/unit/xpcshell.ini]
 [include:docshell/test/unit/xpcshell.ini]
 [include:docshell/test/unit_ipc/xpcshell.ini]
 [include:embedding/tests/unit/xpcshell.ini]
 [include:toolkit/components/commandlines/test/unit/xpcshell.ini]
 [include:toolkit/components/contentprefs/tests/unit/xpcshell.ini]
 [include:toolkit/devtools/debugger/tests/unit/xpcshell.ini]
+[include:toolkit/devtools/sourcemap/tests/unit/xpcshell.ini]
 [include:toolkit/components/passwordmgr/test/unit/xpcshell.ini]
 # Bug 676989: tests hang on Android
 skip-if = os == "android"
 [include:toolkit/components/places/tests/migration/xpcshell.ini]
 [include:toolkit/components/places/tests/autocomplete/xpcshell.ini]
 [include:toolkit/components/places/tests/inline/xpcshell.ini]
 [include:toolkit/components/places/tests/expiration/xpcshell.ini]
 [include:toolkit/components/places/tests/favicons/xpcshell.ini]
--- a/toolkit/devtools/Makefile.in
+++ b/toolkit/devtools/Makefile.in
@@ -6,11 +6,12 @@ DEPTH     = ../..
 topsrcdir = @top_srcdir@
 srcdir    = @srcdir@
 VPATH     = @srcdir@
 
 include $(topsrcdir)/config/config.mk
 
 PARALLEL_DIRS += \
   debugger \
+  sourcemap \
   $(NULL)
 
 include $(topsrcdir)/config/rules.mk
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/Makefile.in
@@ -0,0 +1,19 @@
+#
+# 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/.
+
+DEPTH		= ../../..
+topsrcdir	= @top_srcdir@
+srcdir		= @srcdir@
+VPATH		= @srcdir@
+
+include $(DEPTH)/config/autoconf.mk
+
+# No tests yet
+TEST_DIRS += tests
+
+include $(topsrcdir)/config/rules.mk
+
+libs::
+	$(NSINSTALL) $(srcdir)/*.jsm $(FINAL_TARGET)/modules/devtools
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/SourceMap.jsm
@@ -0,0 +1,1045 @@
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+///////////////////////////////////////////////////////////////////////////////
+
+
+var EXPORTED_SYMBOLS = [ "SourceMapConsumer", "SourceMapGenerator", "SourceNode" ];
+
+Components.utils.import('resource:///modules/devtools/Require.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('source-map/source-map-consumer', ['require', 'exports', 'module' , 'source-map/util', 'source-map/binary-search', 'source-map/array-set', 'source-map/base64-vlq'], function(require, exports, module) {
+
+  var util = require('source-map/util');
+  var binarySearch = require('source-map/binary-search');
+  var ArraySet = require('source-map/array-set').ArraySet;
+  var base64VLQ = require('source-map/base64-vlq');
+
+  // TODO:  bug 673487
+  //
+  // Sometime in the future, if we decide we need to be able to query where in
+  // the generated source a piece of the original code came from, we may want to
+  // add a slot `_originalMappings` which would be an object keyed by the
+  // original source and whose value would be an array of mappings ordered by
+  // original line/col rather than generated (which is what we have now in
+  // `_generatedMappings`).
+
+  /**
+   * A SourceMapConsumer instance represents a parsed source map which we can
+   * query for information about the original file positions by giving it a file
+   * position in the generated source.
+   *
+   * The only parameter is the raw source map (either as a JSON string, or
+   * already parsed to an object). According to the spec, source maps have the
+   * following attributes:
+   *
+   *   - version: Which version of the source map spec this map is following.
+   *   - sources: An array of URLs to the original source files.
+   *   - names: An array of identifiers which can be referrenced by individual mappings.
+   *   - sourceRoot: Optional. The URL root from which all sources are relative.
+   *   - mappings: A string of base64 VLQs which contain the actual mappings.
+   *   - file: The generated file this source map is associated with.
+   *
+   * Here is an example source map, taken from the source map spec[0]:
+   *
+   *     {
+   *       version : 3,
+   *       file: "out.js",
+   *       sourceRoot : "",
+   *       sources: ["foo.js", "bar.js"],
+   *       names: ["src", "maps", "are", "fun"],
+   *       mappings: "AA,AB;;ABCDE;"
+   *     }
+   *
+   * [0]: https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit?pli=1#
+   */
+  function SourceMapConsumer(aSourceMap) {
+    var sourceMap = aSourceMap;
+    if (typeof aSourceMap === 'string') {
+      sourceMap = JSON.parse(aSourceMap);
+    }
+
+    var version = util.getArg(sourceMap, 'version');
+    var sources = util.getArg(sourceMap, 'sources');
+    var names = util.getArg(sourceMap, 'names');
+    var sourceRoot = util.getArg(sourceMap, 'sourceRoot', null);
+    var mappings = util.getArg(sourceMap, 'mappings');
+    var file = util.getArg(sourceMap, 'file');
+
+    if (version !== this._version) {
+      throw new Error('Unsupported version: ' + version);
+    }
+
+    this._names = ArraySet.fromArray(names);
+    this._sources = ArraySet.fromArray(sources);
+
+    // `this._generatedMappings` hold the parsed mapping coordinates from the
+    // source map's "mappings" attribute. Each object in the array is of the
+    // form
+    //
+    //     {
+    //       generatedLine: The line number in the generated code,
+    //       generatedColumn: The column number in the generated code,
+    //       source: The path to the original source file that generated this
+    //               chunk of code,
+    //       originalLine: The line number in the original source that
+    //                     corresponds to this chunk of generated code,
+    //       originalColumn: The column number in the original source that
+    //                       corresponds to this chunk of generated code,
+    //       name: The name of the original symbol which generated this chunk of
+    //             code.
+    //     }
+    //
+    // All properties except for `generatedLine` and `generatedColumn` can be
+    // `null`.
+    this._generatedMappings = [];
+    this._parseMappings(mappings, sourceRoot);
+  }
+
+  /**
+   * The version of the source mapping spec that we are consuming.
+   */
+  SourceMapConsumer.prototype._version = 3;
+
+  /**
+   * Parse the mappings in a string in to a data structure which we can easily
+   * query (an ordered list in this._generatedMappings).
+   */
+  SourceMapConsumer.prototype._parseMappings =
+    function SourceMapConsumer_parseMappings(aStr, aSourceRoot) {
+      var generatedLine = 1;
+      var previousGeneratedColumn = 0;
+      var previousOriginalLine = 0;
+      var previousOriginalColumn = 0;
+      var previousSource = 0;
+      var previousName = 0;
+      var mappingSeparator = /^[,;]/;
+      var str = aStr;
+      var mapping;
+      var temp;
+
+      while (str.length > 0) {
+        if (str.charAt(0) === ';') {
+          generatedLine++;
+          str = str.slice(1);
+          previousGeneratedColumn = 0;
+        }
+        else if (str.charAt(0) === ',') {
+          str = str.slice(1);
+        }
+        else {
+          mapping = {};
+          mapping.generatedLine = generatedLine;
+
+          // Generated column.
+          temp = base64VLQ.decode(str);
+          mapping.generatedColumn = previousGeneratedColumn + temp.value;
+          previousGeneratedColumn = mapping.generatedColumn;
+          str = temp.rest;
+
+          if (str.length > 0 && !mappingSeparator.test(str.charAt(0))) {
+            // Original source.
+            temp = base64VLQ.decode(str);
+            if (aSourceRoot) {
+              mapping.source = util.join(aSourceRoot, this._sources.at(previousSource + temp.value));
+            }
+            else {
+              mapping.source = this._sources.at(previousSource + temp.value);
+            }
+            previousSource += temp.value;
+            str = temp.rest;
+            if (str.length === 0 || mappingSeparator.test(str.charAt(0))) {
+              throw new Error('Found a source, but no line and column');
+            }
+
+            // Original line.
+            temp = base64VLQ.decode(str);
+            mapping.originalLine = previousOriginalLine + temp.value;
+            previousOriginalLine = mapping.originalLine;
+            // Lines are stored 0-based
+            mapping.originalLine += 1;
+            str = temp.rest;
+            if (str.length === 0 || mappingSeparator.test(str.charAt(0))) {
+              throw new Error('Found a source and line, but no column');
+            }
+
+            // Original column.
+            temp = base64VLQ.decode(str);
+            mapping.originalColumn = previousOriginalColumn + temp.value;
+            previousOriginalColumn = mapping.originalColumn;
+            str = temp.rest;
+
+            if (str.length > 0 && !mappingSeparator.test(str.charAt(0))) {
+              // Original name.
+              temp = base64VLQ.decode(str);
+              mapping.name = this._names.at(previousName + temp.value);
+              previousName += temp.value;
+              str = temp.rest;
+            }
+          }
+
+          this._generatedMappings.push(mapping);
+        }
+      }
+    };
+
+  /**
+   * Returns the original source, line, and column information for the generated
+   * source's line and column positions provided. The only argument is an object
+   * with the following properties:
+   *
+   *   - line: The line number in the generated source.
+   *   - column: The column number in the generated source.
+   *
+   * and an object is returned with the following properties:
+   *
+   *   - source: The original source file, or null.
+   *   - line: The line number in the original source, or null.
+   *   - column: The column number in the original source, or null.
+   *   - name: The original identifier, or null.
+   */
+  SourceMapConsumer.prototype.originalPositionFor =
+    function SourceMapConsumer_originalPositionFor(aArgs) {
+      // To return the original position, we must first find the mapping for the
+      // given generated position and then return the original position it
+      // points to. Because the mappings are sorted by generated line/column, we
+      // can use binary search to find the best mapping.
+
+      // To perform a binary search on the mappings, we must be able to compare
+      // two mappings.
+      function compare(mappingA, mappingB) {
+        var cmp = mappingA.generatedLine - mappingB.generatedLine;
+        return cmp === 0
+          ? mappingA.generatedColumn - mappingB.generatedColumn
+          : cmp;
+      }
+
+      // This is the mock of the mapping we are looking for: the needle in the
+      // haystack of mappings.
+      var needle = {
+        generatedLine: util.getArg(aArgs, 'line'),
+        generatedColumn: util.getArg(aArgs, 'column')
+      };
+
+      if (needle.generatedLine <= 0) {
+        throw new TypeError('Line must be greater than or equal to 1.');
+      }
+      if (needle.generatedColumn < 0) {
+        throw new TypeError('Column must be greater than or equal to 0.');
+      }
+
+      var mapping = binarySearch.search(needle, this._generatedMappings, compare);
+
+      if (mapping) {
+        return {
+          source: util.getArg(mapping, 'source', null),
+          line: util.getArg(mapping, 'originalLine', null),
+          column: util.getArg(mapping, 'originalColumn', null),
+          name: util.getArg(mapping, 'name', null)
+        };
+      }
+
+      return {
+        source: null,
+        line: null,
+        column: null,
+        name: null
+      };
+
+    };
+
+  exports.SourceMapConsumer = SourceMapConsumer;
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('source-map/util', ['require', 'exports', 'module' ], function(require, exports, module) {
+
+  /**
+   * This is a helper function for getting values from parameter/options
+   * objects.
+   *
+   * @param args The object we are extracting values from
+   * @param name The name of the property we are getting.
+   * @param defaultValue An optional value to return if the property is missing
+   * from the object. If this is not specified and the property is missing, an
+   * error will be thrown.
+   */
+  function getArg(aArgs, aName, aDefaultValue) {
+    if (aName in aArgs) {
+      return aArgs[aName];
+    } else if (arguments.length === 3) {
+      return aDefaultValue;
+    } else {
+      throw new Error('"' + aName + '" is a required argument.');
+    }
+  }
+  exports.getArg = getArg;
+
+  function join(aRoot, aPath) {
+    return aPath.charAt(0) === '/'
+      ? aPath
+      : aRoot.replace(/\/*$/, '') + '/' + aPath;
+  }
+  exports.join = join;
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('source-map/binary-search', ['require', 'exports', 'module' ], function(require, exports, module) {
+
+  /**
+   * Recursive implementation of binary search.
+   *
+   * @param aLow Indices here and lower do not contain the needle.
+   * @param aHigh Indices here and higher do not contain the needle.
+   * @param aNeedle The element being searched for.
+   * @param aHaystack The non-empty array being searched.
+   * @param aCompare Function which takes two elements and returns -1, 0, or 1.
+   */
+  function recursiveSearch(aLow, aHigh, aNeedle, aHaystack, aCompare) {
+    // This function terminates when one of the following is true:
+    //
+    //   1. We find the exact element we are looking for.
+    //
+    //   2. We did not find the exact element, but we can return the next
+    //      closest element that is less than that element.
+    //
+    //   3. We did not find the exact element, and there is no next-closest
+    //      element which is less than the one we are searching for, so we
+    //      return null.
+    var mid = Math.floor((aHigh - aLow) / 2) + aLow;
+    var cmp = aCompare(aNeedle, aHaystack[mid]);
+    if (cmp === 0) {
+      // Found the element we are looking for.
+      return aHaystack[mid];
+    }
+    else if (cmp > 0) {
+      // aHaystack[mid] is greater than our needle.
+      if (aHigh - mid > 1) {
+        // The element is in the upper half.
+        return recursiveSearch(mid, aHigh, aNeedle, aHaystack, aCompare);
+      }
+      // We did not find an exact match, return the next closest one
+      // (termination case 2).
+      return aHaystack[mid];
+    }
+    else {
+      // aHaystack[mid] is less than our needle.
+      if (mid - aLow > 1) {
+        // The element is in the lower half.
+        return recursiveSearch(aLow, mid, aNeedle, aHaystack, aCompare);
+      }
+      // The exact needle element was not found in this haystack. Determine if
+      // we are in termination case (2) or (3) and return the appropriate thing.
+      return aLow < 0
+        ? null
+        : aHaystack[aLow];
+    }
+  }
+
+  /**
+   * This is an implementation of binary search which will always try and return
+   * the next lowest value checked if there is no exact hit. This is because
+   * mappings between original and generated line/col pairs are single points,
+   * and there is an implicit region between each of them, so a miss just means
+   * that you aren't on the very start of a region.
+   *
+   * @param aNeedle The element you are looking for.
+   * @param aHaystack The array that is being searched.
+   * @param aCompare A function which takes the needle and an element in the
+   *     array and returns -1, 0, or 1 depending on whether the needle is less
+   *     than, equal to, or greater than the element, respectively.
+   */
+  exports.search = function search(aNeedle, aHaystack, aCompare) {
+    return aHaystack.length > 0
+      ? recursiveSearch(-1, aHaystack.length, aNeedle, aHaystack, aCompare)
+      : null;
+  };
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('source-map/array-set', ['require', 'exports', 'module' ], function(require, exports, module) {
+
+  /**
+   * A data structure which is a combination of an array and a set. Adding a new
+   * member is O(1), testing for membership is O(1), and finding the index of an
+   * element is O(1). Removing elements from the set is not supported. Only
+   * strings are supported for membership.
+   */
+  function ArraySet() {
+    this._array = [];
+    this._set = {};
+  }
+
+  /**
+   * Static method for creating ArraySet instances from an existing array.
+   */
+  ArraySet.fromArray = function ArraySet_fromArray(aArray) {
+    var set = new ArraySet();
+    for (var i = 0, len = aArray.length; i < len; i++) {
+      set.add(aArray[i]);
+    }
+    return set;
+  };
+
+  /**
+   * Add the given string to this set.
+   *
+   * @param String str
+   */
+  ArraySet.prototype.add = function ArraySet_add(aStr) {
+    if (this.has(aStr)) {
+      // Already a member; nothing to do.
+      return;
+    }
+    var idx = this._array.length;
+    this._array.push(aStr);
+    this._set[aStr] = idx;
+  };
+
+  /**
+   * Is the given string a member of this set?
+   *
+   * @param String str
+   */
+  ArraySet.prototype.has = function ArraySet_has(aStr) {
+    return Object.prototype.hasOwnProperty.call(this._set, aStr);
+  };
+
+  /**
+   * What is the index of the given string in the array?
+   *
+   * @param String str
+   */
+  ArraySet.prototype.indexOf = function ArraySet_indexOf(aStr) {
+    if (this.has(aStr)) {
+      return this._set[aStr];
+    }
+    throw new Error('"' + aStr + '" is not in the set.');
+  };
+
+  /**
+   * What is the element at the given index?
+   *
+   * @param Number idx
+   */
+  ArraySet.prototype.at = function ArraySet_at(aIdx) {
+    if (aIdx >= 0 && aIdx < this._array.length) {
+      return this._array[aIdx];
+    }
+    throw new Error('No element indexed by ' + aIdx);
+  };
+
+  /**
+   * Returns the array representation of this set (which has the proper indices
+   * indicated by indexOf). Note that this is a copy of the internal array used
+   * for storing the members so that no one can mess with internal state.
+   */
+  ArraySet.prototype.toArray = function ArraySet_toArray() {
+    return this._array.slice();
+  };
+
+  exports.ArraySet = ArraySet;
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ *
+ * Based on the Base 64 VLQ implementation in Closure Compiler:
+ * https://code.google.com/p/closure-compiler/source/browse/trunk/src/com/google/debugging/sourcemap/Base64VLQ.java
+ *
+ * Copyright 2011 The Closure Compiler Authors. All rights reserved.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer in the documentation and/or other materials provided
+ *    with the distribution.
+ *  * Neither the name of Google Inc. nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+define('source-map/base64-vlq', ['require', 'exports', 'module' , 'source-map/base64'], function(require, exports, module) {
+
+  var base64 = require('source-map/base64');
+
+  // A single base 64 digit can contain 6 bits of data. For the base 64 variable
+  // length quantities we use in the source map spec, the first bit is the sign,
+  // the next four bits are the actual value, and the 6th bit is the
+  // continuation bit. The continuation bit tells us whether there are more
+  // digits in this value following this digit.
+  //
+  //   Continuation
+  //   |    Sign
+  //   |    |
+  //   V    V
+  //   101011
+
+  var VLQ_BASE_SHIFT = 5;
+
+  // binary: 100000
+  var VLQ_BASE = 1 << VLQ_BASE_SHIFT;
+
+  // binary: 011111
+  var VLQ_BASE_MASK = VLQ_BASE - 1;
+
+  // binary: 100000
+  var VLQ_CONTINUATION_BIT = VLQ_BASE;
+
+  /**
+   * Converts from a two-complement value to a value where the sign bit is
+   * is placed in the least significant bit.  For example, as decimals:
+   *   1 becomes 2 (10 binary), -1 becomes 3 (11 binary)
+   *   2 becomes 4 (100 binary), -2 becomes 5 (101 binary)
+   */
+  function toVLQSigned(aValue) {
+    return aValue < 0
+      ? ((-aValue) << 1) + 1
+      : (aValue << 1) + 0;
+  }
+
+  /**
+   * Converts to a two-complement value from a value where the sign bit is
+   * is placed in the least significant bit.  For example, as decimals:
+   *   2 (10 binary) becomes 1, 3 (11 binary) becomes -1
+   *   4 (100 binary) becomes 2, 5 (101 binary) becomes -2
+   */
+  function fromVLQSigned(aValue) {
+    var isNegative = (aValue & 1) === 1;
+    var shifted = aValue >> 1;
+    return isNegative
+      ? -shifted
+      : shifted;
+  }
+
+  /**
+   * Returns the base 64 VLQ encoded value.
+   */
+  exports.encode = function base64VLQ_encode(aValue) {
+    var encoded = "";
+    var digit;
+
+    var vlq = toVLQSigned(aValue);
+
+    do {
+      digit = vlq & VLQ_BASE_MASK;
+      vlq >>>= VLQ_BASE_SHIFT;
+      if (vlq > 0) {
+        // There are still more digits in this value, so we must make sure the
+        // continuation bit is marked.
+        digit |= VLQ_CONTINUATION_BIT;
+      }
+      encoded += base64.encode(digit);
+    } while (vlq > 0);
+
+    return encoded;
+  };
+
+  /**
+   * Decodes the next base 64 VLQ value from the given string and returns the
+   * value and the rest of the string.
+   */
+  exports.decode = function base64VLQ_decode(aStr) {
+    var i = 0;
+    var strLen = aStr.length;
+    var result = 0;
+    var shift = 0;
+    var continuation, digit;
+
+    do {
+      if (i >= strLen) {
+        throw new Error("Expected more digits in base 64 VLQ value.");
+      }
+      digit = base64.decode(aStr.charAt(i++));
+      continuation = !!(digit & VLQ_CONTINUATION_BIT);
+      digit &= VLQ_BASE_MASK;
+      result = result + (digit << shift);
+      shift += VLQ_BASE_SHIFT;
+    } while (continuation);
+
+    return {
+      value: fromVLQSigned(result),
+      rest: aStr.slice(i)
+    };
+  };
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('source-map/base64', ['require', 'exports', 'module' ], function(require, exports, module) {
+
+  var charToIntMap = {};
+  var intToCharMap = {};
+
+  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
+    .split('')
+    .forEach(function (ch, index) {
+      charToIntMap[ch] = index;
+      intToCharMap[index] = ch;
+    });
+
+  /**
+   * Encode an integer in the range of 0 to 63 to a single base 64 digit.
+   */
+  exports.encode = function base64_encode(aNumber) {
+    if (aNumber in intToCharMap) {
+      return intToCharMap[aNumber];
+    }
+    throw new TypeError("Must be between 0 and 63: " + aNumber);
+  };
+
+  /**
+   * Decode a single base 64 digit to an integer.
+   */
+  exports.decode = function base64_decode(aChar) {
+    if (aChar in charToIntMap) {
+      return charToIntMap[aChar];
+    }
+    throw new TypeError("Not a valid base 64 digit: " + aChar);
+  };
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('source-map/source-map-generator', ['require', 'exports', 'module' , 'source-map/base64-vlq', 'source-map/util', 'source-map/array-set'], function(require, exports, module) {
+
+  var base64VLQ = require('source-map/base64-vlq');
+  var util = require('source-map/util');
+  var ArraySet = require('source-map/array-set').ArraySet;
+
+  /**
+   * An instance of the SourceMapGenerator represents a source map which is
+   * being built incrementally. To create a new one, you must pass an object
+   * with the following properties:
+   *
+   *   - file: The filename of the generated source.
+   *   - sourceRoot: An optional root for all URLs in this source map.
+   */
+  function SourceMapGenerator(aArgs) {
+    this._file = util.getArg(aArgs, 'file');
+    this._sourceRoot = util.getArg(aArgs, 'sourceRoot', null);
+    this._sources = new ArraySet();
+    this._names = new ArraySet();
+    this._mappings = [];
+  }
+
+  SourceMapGenerator.prototype._version = 3;
+
+  /**
+   * Add a single mapping from original source line and column to the generated
+   * source's line and column for this source map being created. The mapping
+   * object should have the following properties:
+   *
+   *   - generated: An object with the generated line and column positions.
+   *   - original: An object with the original line and column positions.
+   *   - source: The original source file (relative to the sourceRoot).
+   *   - name: An optional original token name for this mapping.
+   */
+  SourceMapGenerator.prototype.addMapping =
+    function SourceMapGenerator_addMapping(aArgs) {
+      var generated = util.getArg(aArgs, 'generated');
+      var original = util.getArg(aArgs, 'original', null);
+      var source = util.getArg(aArgs, 'source', null);
+      var name = util.getArg(aArgs, 'name', null);
+
+      this._validateMapping(generated, original, source, name);
+
+      if (source && !this._sources.has(source)) {
+        this._sources.add(source);
+      }
+
+      if (name && !this._names.has(name)) {
+        this._names.add(name);
+      }
+
+      this._mappings.push({
+        generated: generated,
+        original: original,
+        source: source,
+        name: name
+      });
+    };
+
+  /**
+   * A mapping can have one of the three levels of data:
+   *
+   *   1. Just the generated position.
+   *   2. The Generated position, original position, and original source.
+   *   3. Generated and original position, original source, as well as a name
+   *      token.
+   *
+   * To maintain consistency, we validate that any new mapping being added falls
+   * in to one of these categories.
+   */
+  SourceMapGenerator.prototype._validateMapping =
+    function SourceMapGenerator_validateMapping(aGenerated, aOriginal, aSource,
+                                                aName) {
+      if (aGenerated && 'line' in aGenerated && 'column' in aGenerated
+          && aGenerated.line > 0 && aGenerated.column >= 0
+          && !aOriginal && !aSource && !aName) {
+        // Case 1.
+        return;
+      }
+      else if (aGenerated && 'line' in aGenerated && 'column' in aGenerated
+               && aOriginal && 'line' in aOriginal && 'column' in aOriginal
+               && aGenerated.line > 0 && aGenerated.column >= 0
+               && aOriginal.line > 0 && aOriginal.column >= 0
+               && aSource) {
+        // Cases 2 and 3.
+        return;
+      }
+      else {
+        throw new Error('Invalid mapping.');
+      }
+    };
+
+  /**
+   * Serialize the accumulated mappings in to the stream of base 64 VLQs
+   * specified by the source map format.
+   */
+  SourceMapGenerator.prototype._serializeMappings =
+    function SourceMapGenerator_serializeMappings() {
+      var previousGeneratedColumn = 0;
+      var previousGeneratedLine = 1;
+      var previousOriginalColumn = 0;
+      var previousOriginalLine = 0;
+      var previousName = 0;
+      var previousSource = 0;
+      var result = '';
+      var mapping;
+
+      // The mappings must be guarenteed to be in sorted order before we start
+      // serializing them or else the generated line numbers (which are defined
+      // via the ';' separators) will be all messed up. Note: it might be more
+      // performant to maintain the sorting as we insert them, rather than as we
+      // serialize them, but the big O is the same either way.
+      this._mappings.sort(function (mappingA, mappingB) {
+        var cmp = mappingA.generated.line - mappingB.generated.line;
+        return cmp === 0
+          ? mappingA.generated.column - mappingB.generated.column
+          : cmp;
+      });
+
+      for (var i = 0, len = this._mappings.length; i < len; i++) {
+        mapping = this._mappings[i];
+
+        if (mapping.generated.line !== previousGeneratedLine) {
+          previousGeneratedColumn = 0;
+          while (mapping.generated.line !== previousGeneratedLine) {
+            result += ';';
+            previousGeneratedLine++;
+          }
+        }
+        else {
+          if (i > 0) {
+            result += ',';
+          }
+        }
+
+        result += base64VLQ.encode(mapping.generated.column
+                                   - previousGeneratedColumn);
+        previousGeneratedColumn = mapping.generated.column;
+
+        if (mapping.source && mapping.original) {
+          result += base64VLQ.encode(this._sources.indexOf(mapping.source)
+                                     - previousSource);
+          previousSource = this._sources.indexOf(mapping.source);
+
+          // lines are stored 0-based in SourceMap spec version 3
+          result += base64VLQ.encode(mapping.original.line - 1
+                                     - previousOriginalLine);
+          previousOriginalLine = mapping.original.line - 1;
+
+          result += base64VLQ.encode(mapping.original.column
+                                     - previousOriginalColumn);
+          previousOriginalColumn = mapping.original.column;
+
+          if (mapping.name) {
+            result += base64VLQ.encode(this._names.indexOf(mapping.name)
+                                       - previousName);
+            previousName = this._names.indexOf(mapping.name);
+          }
+        }
+      }
+
+      return result;
+    };
+
+  /**
+   * Render the source map being generated to a string.
+   */
+  SourceMapGenerator.prototype.toString =
+    function SourceMapGenerator_toString() {
+      var map = {
+        version: this._version,
+        file: this._file,
+        sources: this._sources.toArray(),
+        names: this._names.toArray(),
+        mappings: this._serializeMappings()
+      };
+      if (this._sourceRoot) {
+        map.sourceRoot = this._sourceRoot;
+      }
+      return JSON.stringify(map);
+    };
+
+  exports.SourceMapGenerator = SourceMapGenerator;
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('source-map/source-node', ['require', 'exports', 'module' , 'source-map/source-map-generator'], function(require, exports, module) {
+
+  var SourceMapGenerator = require('source-map/source-map-generator').SourceMapGenerator;
+
+  /**
+   * SourceNodes provide a way to abstract over interpolating/concatenating
+   * snippets of generated JavaScript source code while maintaining the line and
+   * column information associated with the original source code.
+   *
+   * @param aLine The original line number.
+   * @param aColumn The original column number.
+   * @param aSource The original source's filename.
+   * @param aChunks Optional. An array of strings which are snippets of
+   *        generated JS, or other SourceNodes.
+   */
+  function SourceNode(aLine, aColumn, aSource, aChunks) {
+    this.children = [];
+    this.line = aLine;
+    this.column = aColumn;
+    this.source = aSource;
+    if (aChunks != null) this.add(aChunks);
+  }
+
+  /**
+   * Add a chunk of generated JS to this source node.
+   *
+   * @param aChunk A string snippet of generated JS code, another instance of
+   *        SourceNode, or an array where each member is one of those things.
+   */
+  SourceNode.prototype.add = function SourceNode_add(aChunk) {
+    if (Array.isArray(aChunk)) {
+      aChunk.forEach(function (chunk) {
+        this.add(chunk);
+      }, this);
+    }
+    else if (aChunk instanceof SourceNode || typeof aChunk === "string") {
+      this.children.push(aChunk);
+    }
+    else {
+      throw new TypeError(
+        "Expected a SourceNode, string, or an array of SourceNodes and strings. Got " + aChunk
+      );
+    }
+    return this;
+  };
+
+  /**
+   * Add a chunk of generated JS to the beginning of this source node.
+   *
+   * @param aChunk A string snippet of generated JS code, another instance of
+   *        SourceNode, or an array where each member is one of those things.
+   */
+  SourceNode.prototype.prepend = function SourceNode_prepend(aChunk) {
+    if (Array.isArray(aChunk)) {
+      for (var i = aChunk.length-1; i >= 0; i--) {
+        this.prepend(aChunk[i]);
+      }
+    }
+    else if (aChunk instanceof SourceNode || typeof aChunk === "string") {
+      this.children.unshift(aChunk);
+    }
+    else {
+      throw new TypeError(
+        "Expected a SourceNode, string, or an array of SourceNodes and strings. Got " + aChunk
+      );
+    }
+    return this;
+  };
+
+  /**
+   * Walk over the tree of JS snippets in this node and its children. The
+   * walking function is called once for each snippet of JS and is passed that
+   * snippet and the its original associated source's line/column location.
+   *
+   * @param aFn The traversal function.
+   */
+  SourceNode.prototype.walk = function SourceNode_walk(aFn) {
+    this.children.forEach(function (chunk) {
+      if (chunk instanceof SourceNode) {
+        chunk.walk(aFn);
+      }
+      else {
+        if (chunk !== '') {
+          aFn(chunk, { source: this.source, line: this.line, column: this.column });
+        }
+      }
+    }, this);
+  };
+
+  /**
+   * Like `String.prototype.join` except for SourceNodes. Inserts `aStr` between
+   * each of `this.children`.
+   *
+   * @param aSep The separator.
+   */
+  SourceNode.prototype.join = function SourceNode_join(aSep) {
+    var newChildren;
+    var i;
+    var len = this.children.length
+    if (len > 0) {
+      newChildren = [];
+      for (i = 0; i < len-1; i++) {
+        newChildren.push(this.children[i]);
+        newChildren.push(aSep);
+      }
+      newChildren.push(this.children[i]);
+      this.children = newChildren;
+    }
+    return this;
+  };
+
+  /**
+   * Call String.prototype.replace on the very right-most source snippet. Useful
+   * for trimming whitespace from the end of a source node, etc.
+   *
+   * @param aPattern The pattern to replace.
+   * @param aReplacement The thing to replace the pattern with.
+   */
+  SourceNode.prototype.replaceRight = function SourceNode_replaceRight(aPattern, aReplacement) {
+    var lastChild = this.children[this.children.length - 1];
+    if (lastChild instanceof SourceNode) {
+      lastChild.replaceRight(aPattern, aReplacement);
+    }
+    else if (typeof lastChild === 'string') {
+      this.children[this.children.lenth - 1] = lastChild.replace(aPattern, aReplacement);
+    }
+    else {
+      this.children.push(''.replace(aPattern, aReplacement));
+    }
+    return this;
+  };
+
+  /**
+   * Return the string representation of this source node. Walks over the tree
+   * and concatenates all the various snippets together to one string.
+   */
+  SourceNode.prototype.toString = function SourceNode_toString() {
+    var str = "";
+    this.walk(function (chunk) {
+      str += chunk;
+    });
+    return str;
+  };
+
+  /**
+   * Returns the string representation of this source node along with a source
+   * map.
+   */
+  SourceNode.prototype.toStringWithSourceMap = function SourceNode_toStringWithSourceMap(aArgs) {
+    var generated = {
+      code: "",
+      line: 1,
+      column: 0
+    };
+    var map = new SourceMapGenerator(aArgs);
+    this.walk(function (chunk, original) {
+      generated.code += chunk;
+      if (original.source != null
+          && original.line != null
+          && original.column != null) {
+        map.addMapping({
+          source: original.source,
+          original: {
+            line: original.line,
+            column: original.column
+          },
+          generated: {
+            line: generated.line,
+            column: generated.column
+          }
+        });
+      }
+      chunk.split('').forEach(function (char) {
+        if (char === '\n') {
+          generated.line++;
+          generated.column = 0;
+        } else {
+          generated.column++;
+        }
+      });
+    });
+
+    return { code: generated.code, map: map };
+  };
+
+  exports.SourceNode = SourceNode;
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+///////////////////////////////////////////////////////////////////////////////
+
+let SourceMapConsumer = require('source-map/source-map-consumer').SourceMapConsumer;
+let SourceMapGenerator = require('source-map/source-map-generator').SourceMapGenerator;
+let SourceNode = require('source-map/source-node').SourceNode;
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/Makefile.in
@@ -0,0 +1,17 @@
+# 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/.
+
+DEPTH           = ../../../..
+topsrcdir       = @top_srcdir@
+srcdir          = @srcdir@
+VPATH           = @srcdir@
+relativesrcdir  = toolkit/devtools/sourcemap/tests
+
+include $(DEPTH)/config/autoconf.mk
+
+MODULE          = test_sourcemap
+
+XPCSHELL_TESTS  = unit
+
+include $(topsrcdir)/config/rules.mk
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/Utils.jsm
@@ -0,0 +1,152 @@
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource:///modules/devtools/Require.jsm');
+Components.utils.import('resource:///modules/devtools/SourceMap.jsm');
+
+let EXPORTED_SYMBOLS = [ "define", "runSourceMapTests" ];
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('test/source-map/assert', ['exports'], function (exports) {
+
+  let do_throw = function (msg) {
+    throw new Error(msg);
+  };
+
+  exports.init = function (throw_fn) {
+    do_throw = throw_fn;
+  };
+
+  exports.doesNotThrow = function (fn) {
+    try {
+      fn();
+    }
+    catch (e) {
+      do_throw(e.message);
+    }
+  };
+
+  exports.equal = function (actual, expected, msg) {
+    msg = msg || String(actual) + ' != ' + String(expected);
+    if (actual != expected) {
+      do_throw(msg);
+    }
+  };
+
+  exports.ok = function (val, msg) {
+    msg = msg || String(val) + ' is falsey';
+    if (!Boolean(val)) {
+      do_throw(msg);
+    }
+  };
+
+  exports.strictEqual = function (actual, expected, msg) {
+    msg = msg || String(actual) + ' !== ' + String(expected);
+    if (actual !== expected) {
+      do_throw(msg);
+    }
+  };
+
+  exports.throws = function (fn) {
+    try {
+      fn();
+      do_throw('Expected an error to be thrown, but it wasn\'t.');
+    }
+    catch (e) {
+    }
+  };
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define('test/source-map/util', ['require', 'exports', 'module' ], function(require, exports, module) {
+
+  // This is a test mapping which maps functions from two different files
+  // (one.js and two.js) to a minified generated source.
+  //
+  // Here is one.js:
+  //
+  //   ONE.foo = function (bar) {
+  //     return baz(bar);
+  //   };
+  //
+  // Here is two.js:
+  //
+  //   TWO.inc = function (n) {
+  //     return n + 1;
+  //   };
+  //
+  // And here is the generated code (min.js):
+  //
+  //   ONE.foo=function(a){return baz(a);};
+  //   TWO.inc=function(a){return a+1;};
+  exports.testMap = {
+    version: 3,
+    file: 'min.js',
+    names: ['bar', 'baz', 'n'],
+    sources: ['one.js', 'two.js'],
+    sourceRoot: '/the/root',
+    mappings: 'CAAC,IAAI,IAAM,SAAUA,GAClB,OAAOC,IAAID;CCDb,IAAI,IAAM,SAAUE,GAClB,OAAOA'
+  };
+
+  function assertMapping(generatedLine, generatedColumn, originalSource,
+                         originalLine, originalColumn, name, map, assert) {
+    var mapping = map.originalPositionFor({
+      line: generatedLine,
+      column: generatedColumn
+    });
+    assert.equal(mapping.name, name,
+                 'Incorrect name, expected ' + JSON.stringify(name)
+                 + ', got ' + JSON.stringify(mapping.name));
+    assert.equal(mapping.line, originalLine,
+                 'Incorrect line, expected ' + JSON.stringify(originalLine)
+                 + ', got ' + JSON.stringify(mapping.line));
+    assert.equal(mapping.column, originalColumn,
+                 'Incorrect column, expected ' + JSON.stringify(originalColumn)
+                 + ', got ' + JSON.stringify(mapping.column));
+    assert.equal(mapping.source, originalSource,
+                 'Incorrect source, expected ' + JSON.stringify(originalSource)
+                 + ', got ' + JSON.stringify(mapping.source));
+  }
+  exports.assertMapping = assertMapping;
+
+});
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+function runSourceMapTests(modName, do_throw) {
+  let mod = require(modName);
+  let assert = require('test/source-map/assert');
+  let util = require('test/source-map/util');
+
+  assert.init(do_throw);
+
+  for (let k in mod) {
+    if (/^test/.test(k)) {
+      mod[k](assert, util);
+    }
+  }
+
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/head_sourcemap.js
@@ -0,0 +1,8 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+const Cr = Components.results;
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_array_set.js
@@ -0,0 +1,71 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-array-set", ["require", "exports", "module"], function (require, exports, module) {
+
+  var ArraySet = require('source-map/array-set').ArraySet;
+
+  function makeTestSet() {
+    var set = new ArraySet();
+    for (var i = 0; i < 100; i++) {
+      set.add(String(i));
+    }
+    return set;
+  }
+
+  exports['test .has() membership'] = function (assert, util) {
+    var set = makeTestSet();
+    for (var i = 0; i < 100; i++) {
+      assert.ok(set.has(String(i)));
+    }
+  };
+
+  exports['test .indexOf() elements'] = function (assert, util) {
+    var set = makeTestSet();
+    for (var i = 0; i < 100; i++) {
+      assert.strictEqual(set.indexOf(String(i)), i);
+    }
+  };
+
+  exports['test .at() indexing'] = function (assert, util) {
+    var set = makeTestSet();
+    for (var i = 0; i < 100; i++) {
+      assert.strictEqual(set.at(i), String(i));
+    }
+  };
+
+  exports['test creating from an array'] = function (assert, util) {
+    var set = ArraySet.fromArray(['foo', 'bar', 'baz', 'quux', 'hasOwnProperty']);
+
+    assert.ok(set.has('foo'));
+    assert.ok(set.has('bar'));
+    assert.ok(set.has('baz'));
+    assert.ok(set.has('quux'));
+    assert.ok(set.has('hasOwnProperty'));
+
+    assert.strictEqual(set.indexOf('foo'), 0);
+    assert.strictEqual(set.indexOf('bar'), 1);
+    assert.strictEqual(set.indexOf('baz'), 2);
+    assert.strictEqual(set.indexOf('quux'), 3);
+
+    assert.strictEqual(set.at(0), 'foo');
+    assert.strictEqual(set.at(1), 'bar');
+    assert.strictEqual(set.at(2), 'baz');
+    assert.strictEqual(set.at(3), 'quux');
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-array-set', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_base64.js
@@ -0,0 +1,43 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-base64", ["require", "exports", "module"], function (require, exports, module) {
+
+  var base64 = require('source-map/base64');
+
+  exports['test out of range encoding'] = function (assert, util) {
+    assert.throws(function () {
+      base64.encode(-1);
+    });
+    assert.throws(function () {
+      base64.encode(64);
+    });
+  };
+
+  exports['test out of range decoding'] = function (assert, util) {
+    assert.throws(function () {
+      base64.decode('=');
+    });
+  };
+
+  exports['test normal encoding and decoding'] = function (assert, util) {
+    for (var i = 0; i < 64; i++) {
+      assert.equal(base64.decode(base64.encode(i)), i);
+    }
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-base64', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_base64_vlq.js
@@ -0,0 +1,32 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-base64-vlq", ["require", "exports", "module"], function (require, exports, module) {
+
+  var base64VLQ = require('source-map/base64-vlq');
+
+  exports['test normal encoding and decoding'] = function (assert, util) {
+    var result;
+    for (var i = -255; i < 256; i++) {
+      result = base64VLQ.decode(base64VLQ.encode(i));
+      assert.ok(result);
+      assert.equal(result.value, i);
+      assert.equal(result.rest, "");
+    }
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-base64-vlq', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_binary_search.js
@@ -0,0 +1,62 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-binary-search", ["require", "exports", "module"], function (require, exports, module) {
+
+  var binarySearch = require('source-map/binary-search');
+
+  function numberCompare(a, b) {
+    return a - b;
+  }
+
+  exports['test too high'] = function (assert, util) {
+    var needle = 30;
+    var haystack = [2,4,6,8,10,12,14,16,18,20];
+
+    assert.doesNotThrow(function () {
+      binarySearch.search(needle, haystack, numberCompare);
+    });
+
+    assert.equal(binarySearch.search(needle, haystack, numberCompare), 20);
+  };
+
+  exports['test too low'] = function (assert, util) {
+    var needle = 1;
+    var haystack = [2,4,6,8,10,12,14,16,18,20];
+
+    assert.doesNotThrow(function () {
+      binarySearch.search(needle, haystack, numberCompare);
+    });
+
+    assert.equal(binarySearch.search(needle, haystack, numberCompare), null);
+  };
+
+  exports['test exact search'] = function (assert, util) {
+    var needle = 4;
+    var haystack = [2,4,6,8,10,12,14,16,18,20];
+
+    assert.equal(binarySearch.search(needle, haystack, numberCompare), 4);
+  };
+
+  exports['test fuzzy search'] = function (assert, util) {
+    var needle = 19;
+    var haystack = [2,4,6,8,10,12,14,16,18,20];
+
+    assert.equal(binarySearch.search(needle, haystack, numberCompare), 18);
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-binary-search', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_dog_fooding.js
@@ -0,0 +1,72 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-dog-fooding", ["require", "exports", "module"], function (require, exports, module) {
+
+  var SourceMapConsumer = require('source-map/source-map-consumer').SourceMapConsumer;
+  var SourceMapGenerator = require('source-map/source-map-generator').SourceMapGenerator;
+
+  exports['test eating our own dog food'] = function (assert, util) {
+    var smg = new SourceMapGenerator({
+      file: 'testing.js',
+      sourceRoot: '/wu/tang'
+    });
+
+    smg.addMapping({
+      source: 'gza.coffee',
+      original: { line: 1, column: 0 },
+      generated: { line: 2, column: 2 }
+    });
+
+    smg.addMapping({
+      source: 'gza.coffee',
+      original: { line: 2, column: 0 },
+      generated: { line: 3, column: 2 }
+    });
+
+    smg.addMapping({
+      source: 'gza.coffee',
+      original: { line: 3, column: 0 },
+      generated: { line: 4, column: 2 }
+    });
+
+    smg.addMapping({
+      source: 'gza.coffee',
+      original: { line: 4, column: 0 },
+      generated: { line: 5, column: 2 }
+    });
+
+    var smc = new SourceMapConsumer(smg.toString());
+
+    // Exact
+    util.assertMapping(2, 2, '/wu/tang/gza.coffee', 1, 0, null, smc, assert);
+    util.assertMapping(3, 2, '/wu/tang/gza.coffee', 2, 0, null, smc, assert);
+    util.assertMapping(4, 2, '/wu/tang/gza.coffee', 3, 0, null, smc, assert);
+    util.assertMapping(5, 2, '/wu/tang/gza.coffee', 4, 0, null, smc, assert);
+
+    // Fuzzy
+    util.assertMapping(2, 0, null, null, null, null, smc, assert);
+    util.assertMapping(2, 9, '/wu/tang/gza.coffee', 1, 0, null, smc, assert);
+    util.assertMapping(3, 0, '/wu/tang/gza.coffee', 1, 0, null, smc, assert);
+    util.assertMapping(3, 9, '/wu/tang/gza.coffee', 2, 0, null, smc, assert);
+    util.assertMapping(4, 0, '/wu/tang/gza.coffee', 2, 0, null, smc, assert);
+    util.assertMapping(4, 9, '/wu/tang/gza.coffee', 3, 0, null, smc, assert);
+    util.assertMapping(5, 0, '/wu/tang/gza.coffee', 3, 0, null, smc, assert);
+    util.assertMapping(5, 9, '/wu/tang/gza.coffee', 4, 0, null, smc, assert);
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-dog-fooding', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_source_map_consumer.js
@@ -0,0 +1,75 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-source-map-consumer", ["require", "exports", "module"], function (require, exports, module) {
+
+  var SourceMapConsumer = require('source-map/source-map-consumer').SourceMapConsumer;
+
+  exports['test that we can instantiate with a string or an objects'] = function (assert, util) {
+    assert.doesNotThrow(function () {
+      var map = new SourceMapConsumer(util.testMap);
+    });
+    assert.doesNotThrow(function () {
+      var map = new SourceMapConsumer(JSON.stringify(util.testMap));
+    });
+  };
+
+  exports['test that the source root is reflected in a mapping\'s source field'] = function (assert, util) {
+    var map = new SourceMapConsumer(util.testMap);
+    var mapping;
+
+    mapping = map.originalPositionFor({
+      line: 2,
+      column: 1
+    });
+    assert.equal(mapping.source, '/the/root/two.js');
+
+    mapping = map.originalPositionFor({
+      line: 1,
+      column: 1
+    });
+    assert.equal(mapping.source, '/the/root/one.js');
+  };
+
+  exports['test mapping tokens back exactly'] = function (assert, util) {
+    var map = new SourceMapConsumer(util.testMap);
+
+    util.assertMapping(1, 1, '/the/root/one.js', 1, 1, null, map, assert);
+    util.assertMapping(1, 5, '/the/root/one.js', 1, 5, null, map, assert);
+    util.assertMapping(1, 9, '/the/root/one.js', 1, 11, null, map, assert);
+    util.assertMapping(1, 18, '/the/root/one.js', 1, 21, 'bar', map, assert);
+    util.assertMapping(1, 21, '/the/root/one.js', 2, 3, null, map, assert);
+    util.assertMapping(1, 28, '/the/root/one.js', 2, 10, 'baz', map, assert);
+    util.assertMapping(1, 32, '/the/root/one.js', 2, 14, 'bar', map, assert);
+
+    util.assertMapping(2, 1, '/the/root/two.js', 1, 1, null, map, assert);
+    util.assertMapping(2, 5, '/the/root/two.js', 1, 5, null, map, assert);
+    util.assertMapping(2, 9, '/the/root/two.js', 1, 11, null, map, assert);
+    util.assertMapping(2, 18, '/the/root/two.js', 1, 21, 'n', map, assert);
+    util.assertMapping(2, 21, '/the/root/two.js', 2, 3, null, map, assert);
+    util.assertMapping(2, 28, '/the/root/two.js', 2, 10, 'n', map, assert);
+  };
+
+  exports['test mapping tokens back fuzzy'] = function (assert, util) {
+    var map = new SourceMapConsumer(util.testMap);
+
+    util.assertMapping(1, 20, '/the/root/one.js', 1, 21, 'bar', map, assert);
+    util.assertMapping(1, 30, '/the/root/one.js', 2, 10, 'baz', map, assert);
+    util.assertMapping(2, 12, '/the/root/two.js', 1, 11, null, map, assert);
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-source-map-consumer', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_source_map_generator.js
@@ -0,0 +1,187 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-source-map-generator", ["require", "exports", "module"], function (require, exports, module) {
+
+  var SourceMapGenerator = require('source-map/source-map-generator').SourceMapGenerator;
+
+  exports['test some simple stuff'] = function (assert, util) {
+    var map = new SourceMapGenerator({
+      file: 'foo.js',
+      sourceRoot: '.'
+    });
+    assert.ok(true);
+  };
+
+  exports['test adding mappings (case 1)'] = function (assert, util) {
+    var map = new SourceMapGenerator({
+      file: 'generated-foo.js',
+      sourceRoot: '.'
+    });
+
+    assert.doesNotThrow(function () {
+      map.addMapping({
+        generated: { line: 1, column: 1 }
+      });
+    });
+  };
+
+  exports['test adding mappings (case 2)'] = function (assert, util) {
+    var map = new SourceMapGenerator({
+      file: 'generated-foo.js',
+      sourceRoot: '.'
+    });
+
+    assert.doesNotThrow(function () {
+      map.addMapping({
+        generated: { line: 1, column: 1 },
+        source: 'bar.js',
+        original: { line: 1, column: 1 }
+      });
+    });
+  };
+
+  exports['test adding mappings (case 3)'] = function (assert, util) {
+    var map = new SourceMapGenerator({
+      file: 'generated-foo.js',
+      sourceRoot: '.'
+    });
+
+    assert.doesNotThrow(function () {
+      map.addMapping({
+        generated: { line: 1, column: 1 },
+        source: 'bar.js',
+        original: { line: 1, column: 1 },
+        name: 'someToken'
+      });
+    });
+  };
+
+  exports['test adding mappings (invalid)'] = function (assert, util) {
+    var map = new SourceMapGenerator({
+      file: 'generated-foo.js',
+      sourceRoot: '.'
+    });
+
+    // Not enough info.
+    assert.throws(function () {
+      map.addMapping({});
+    });
+
+    // Original file position, but no source.
+    assert.throws(function () {
+      map.addMapping({
+        generated: { line: 1, column: 1 },
+        original: { line: 1, column: 1 }
+      });
+    });
+  };
+
+  exports['test that the correct mappings are being generated'] = function (assert, util) {
+    var map = new SourceMapGenerator({
+      file: 'min.js',
+      sourceRoot: '/the/root'
+    });
+
+    map.addMapping({
+      generated: { line: 1, column: 1 },
+      original: { line: 1, column: 1 },
+      source: 'one.js'
+    });
+    map.addMapping({
+      generated: { line: 1, column: 5 },
+      original: { line: 1, column: 5 },
+      source: 'one.js'
+    });
+    map.addMapping({
+      generated: { line: 1, column: 9 },
+      original: { line: 1, column: 11 },
+      source: 'one.js'
+    });
+    map.addMapping({
+      generated: { line: 1, column: 18 },
+      original: { line: 1, column: 21 },
+      source: 'one.js',
+      name: 'bar'
+    });
+    map.addMapping({
+      generated: { line: 1, column: 21 },
+      original: { line: 2, column: 3 },
+      source: 'one.js'
+    });
+    map.addMapping({
+      generated: { line: 1, column: 28 },
+      original: { line: 2, column: 10 },
+      source: 'one.js',
+      name: 'baz'
+    });
+    map.addMapping({
+      generated: { line: 1, column: 32 },
+      original: { line: 2, column: 14 },
+      source: 'one.js',
+      name: 'bar'
+    });
+
+    map.addMapping({
+      generated: { line: 2, column: 1 },
+      original: { line: 1, column: 1 },
+      source: 'two.js'
+    });
+    map.addMapping({
+      generated: { line: 2, column: 5 },
+      original: { line: 1, column: 5 },
+      source: 'two.js'
+    });
+    map.addMapping({
+      generated: { line: 2, column: 9 },
+      original: { line: 1, column: 11 },
+      source: 'two.js'
+    });
+    map.addMapping({
+      generated: { line: 2, column: 18 },
+      original: { line: 1, column: 21 },
+      source: 'two.js',
+      name: 'n'
+    });
+    map.addMapping({
+      generated: { line: 2, column: 21 },
+      original: { line: 2, column: 3 },
+      source: 'two.js'
+    });
+    map.addMapping({
+      generated: { line: 2, column: 28 },
+      original: { line: 2, column: 10 },
+      source: 'two.js',
+      name: 'n'
+    });
+
+    map = JSON.parse(map.toString());
+
+    assert.equal(map.version, 3);
+    assert.equal(map.file, 'min.js');
+    assert.equal(map.names.length, 3);
+    assert.equal(map.names[0], 'bar');
+    assert.equal(map.names[1], 'baz');
+    assert.equal(map.names[2], 'n');
+    assert.equal(map.sources.length, 2);
+    assert.equal(map.sources[0], 'one.js');
+    assert.equal(map.sources[1], 'two.js');
+    assert.equal(map.sourceRoot, '/the/root');
+    assert.equal(map.mappings, 'CAAC,IAAI,IAAM,SAAUA,GAClB,OAAOC,IAAID;CCDb,IAAI,IAAM,SAAUE,GAClB,OAAOA');
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-source-map-generator', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/test_source_node.js
@@ -0,0 +1,155 @@
+/*
+ * WARNING!
+ *
+ * Do not edit this file directly, it is built from the sources at
+ * https://github.com/mozilla/source-map/
+ */
+
+Components.utils.import('resource://test/Utils.jsm');
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+define("test/source-map/test-source-node", ["require", "exports", "module"], function (require, exports, module) {
+
+  var SourceMapGenerator = require('source-map/source-map-generator').SourceMapGenerator;
+  var SourceMapConsumer = require('source-map/source-map-consumer').SourceMapConsumer;
+  var SourceNode = require('source-map/source-node').SourceNode;
+
+  exports['test .add()'] = function (assert, util) {
+    var node = new SourceNode(null, null, null);
+
+    // Adding a string works.
+    node.add('function noop() {}');
+
+    // Adding another source node works.
+    node.add(new SourceNode(null, null, null));
+
+    // Adding an array works.
+    node.add(['function foo() {',
+              new SourceNode(null, null, null,
+                             'return 10;'),
+              '}']);
+
+    // Adding other stuff doesn't.
+    assert.throws(function () {
+      node.add({});
+    });
+    assert.throws(function () {
+      node.add(function () {});
+    });
+  };
+
+  exports['test .prepend()'] = function (assert, util) {
+    var node = new SourceNode(null, null, null);
+
+    // Prepending a string works.
+    node.prepend('function noop() {}');
+    assert.equal(node.children[0], 'function noop() {}');
+    assert.equal(node.children.length, 1);
+
+    // Prepending another source node works.
+    node.prepend(new SourceNode(null, null, null));
+    assert.equal(node.children[0], '');
+    assert.equal(node.children[1], 'function noop() {}');
+    assert.equal(node.children.length, 2);
+
+    // Prepending an array works.
+    node.prepend(['function foo() {',
+              new SourceNode(null, null, null,
+                             'return 10;'),
+              '}']);
+    assert.equal(node.children[0], 'function foo() {');
+    assert.equal(node.children[1], 'return 10;');
+    assert.equal(node.children[2], '}');
+    assert.equal(node.children[3], '');
+    assert.equal(node.children[4], 'function noop() {}');
+    assert.equal(node.children.length, 5);
+
+    // Prepending other stuff doesn't.
+    assert.throws(function () {
+      node.prepend({});
+    });
+    assert.throws(function () {
+      node.prepend(function () {});
+    });
+  };
+
+  exports['test .toString()'] = function (assert, util) {
+    assert.equal((new SourceNode(null, null, null,
+                                 ['function foo() {',
+                                  new SourceNode(null, null, null, 'return 10;'),
+                                  '}'])).toString(),
+                 'function foo() {return 10;}');
+  };
+
+  exports['test .join()'] = function (assert, util) {
+    assert.equal((new SourceNode(null, null, null,
+                                 ['a', 'b', 'c', 'd'])).join(', ').toString(),
+                 'a, b, c, d');
+  };
+
+  exports['test .walk()'] = function (assert, util) {
+    var node = new SourceNode(null, null, null,
+                              ['(function () {\n',
+                               '  ', new SourceNode(1, 0, 'a.js', ['someCall()']), ';\n',
+                               '  ', new SourceNode(2, 0, 'b.js', ['if (foo) bar()']), ';\n',
+                               '}());']);
+    var expected = [
+      { str: '(function () {\n', source: null,   line: null, column: null },
+      { str: '  ',               source: null,   line: null, column: null },
+      { str: 'someCall()',       source: 'a.js', line: 1,    column: 0    },
+      { str: ';\n',              source: null,   line: null, column: null },
+      { str: '  ',               source: null,   line: null, column: null },
+      { str: 'if (foo) bar()',   source: 'b.js', line: 2,    column: 0    },
+      { str: ';\n',              source: null,   line: null, column: null },
+      { str: '}());',            source: null,   line: null, column: null },
+    ];
+    var i = 0;
+    node.walk(function (chunk, loc) {
+      assert.equal(expected[i].str, chunk);
+      assert.equal(expected[i].source, loc.source);
+      assert.equal(expected[i].line, loc.line);
+      assert.equal(expected[i].column, loc.column);
+      i++;
+    });
+  };
+
+  exports['test .toStringWithSourceMap()'] = function (assert, util) {
+    var node = new SourceNode(null, null, null,
+                              ['(function () {\n',
+                               '  ', new SourceNode(1, 0, 'a.js', ['someCall()']), ';\n',
+                               '  ', new SourceNode(2, 0, 'b.js', ['if (foo) bar()']), ';\n',
+                               '}());']);
+    var map = node.toStringWithSourceMap({
+      file: 'foo.js'
+    }).map;
+
+    assert.ok(map instanceof SourceMapGenerator, 'map instanceof SourceMapGenerator');
+    map = new SourceMapConsumer(map.toString());
+
+    var actual;
+
+    actual = map.originalPositionFor({
+      line: 2,
+      column: 2
+    });
+    assert.equal(actual.source, 'a.js');
+    assert.equal(actual.line, 1);
+    assert.equal(actual.column, 0);
+
+    actual = map.originalPositionFor({
+      line: 3,
+      column: 2
+    });
+    assert.equal(actual.source, 'b.js');
+    assert.equal(actual.line, 2);
+    assert.equal(actual.column, 0);
+  };
+
+});
+function run_test() {
+  runSourceMapTests('test/source-map/test-source-node', do_throw);
+}
new file mode 100644
--- /dev/null
+++ b/toolkit/devtools/sourcemap/tests/unit/xpcshell.ini
@@ -0,0 +1,12 @@
+[DEFAULT]
+head = head_sourcemap.js
+tail =
+
+[test_source_node.js]
+[test_source_map_generator.js]
+[test_source_map_consumer.js]
+[test_dog_fooding.js]
+[test_binary_search.js]
+[test_base64_vlq.js]
+[test_base64.js]
+[test_array_set.js]