DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (d8847129d134)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809
/* vim:set ts=2 sw=2 sts=2 et: */
/* 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";

this.EXPORTED_SYMBOLS = ["StyleSheetEditor", "prettifyCSS"];

const Cc = Components.classes;
const Ci = Components.interfaces;
const Cu = Components.utils;

const require = Cu.import("resource://gre/modules/devtools/Loader.jsm", {}).devtools.require;
const Editor  = require("devtools/sourceeditor/editor");
const {Promise: promise} = Cu.import("resource://gre/modules/Promise.jsm", {});
const {CssLogic} = require("devtools/styleinspector/css-logic");

Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/FileUtils.jsm");
Cu.import("resource://gre/modules/NetUtil.jsm");
Cu.import("resource://gre/modules/osfile.jsm");
Cu.import("resource://gre/modules/Task.jsm");
Cu.import("resource://gre/modules/devtools/event-emitter.js");
Cu.import("resource:///modules/devtools/StyleEditorUtil.jsm");

const LOAD_ERROR = "error-load";
const SAVE_ERROR = "error-save";

// max update frequency in ms (avoid potential typing lag and/or flicker)
// @see StyleEditor.updateStylesheet
const UPDATE_STYLESHEET_THROTTLE_DELAY = 500;

// Pref which decides if CSS autocompletion is enabled in Style Editor or not.
const AUTOCOMPLETION_PREF = "devtools.styleeditor.autocompletion-enabled";

// Pref which decides whether updates to the stylesheet use transitions
const TRANSITION_PREF = "devtools.styleeditor.transitions";

// How long to wait to update linked CSS file after original source was saved
// to disk. Time in ms.
const CHECK_LINKED_SHEET_DELAY=500;

// How many times to check for linked file changes
const MAX_CHECK_COUNT=10;

// The classname used to show a line that is not used
const UNUSED_CLASS = "cm-unused-line";

// How much time should the mouse be still before the selector at that position
// gets highlighted?
const SELECTOR_HIGHLIGHT_TIMEOUT = 500;

/**
 * StyleSheetEditor controls the editor linked to a particular StyleSheet
 * object.
 *
 * Emits events:
 *   'property-change': A property on the underlying stylesheet has changed
 *   'source-editor-load': The source editor for this editor has been loaded
 *   'error': An error has occured
 *
 * @param {StyleSheet|OriginalSource}  styleSheet
 *        Stylesheet or original source to show
 * @param {DOMWindow}  win
 *        panel window for style editor
 * @param {nsIFile}  file
 *        Optional file that the sheet was imported from
 * @param {boolean} isNew
 *        Optional whether the sheet was created by the user
 * @param {Walker} walker
 *        Optional walker used for selectors autocompletion
 * @param {CustomHighlighterFront} highlighter
 *        Optional highlighter front for the SelectorHighligher used to
 *        highlight selectors
 */
function StyleSheetEditor(styleSheet, win, file, isNew, walker, highlighter) {
  EventEmitter.decorate(this);

  this.styleSheet = styleSheet;
  this._inputElement = null;
  this.sourceEditor = null;
  this._window = win;
  this._isNew = isNew;
  this.walker = walker;
  this.highlighter = highlighter;

  this._state = {   // state to use when inputElement attaches
    text: "",
    selection: {
      start: {line: 0, ch: 0},
      end: {line: 0, ch: 0}
    },
    topIndex: 0              // the first visible line
  };

  this._styleSheetFilePath = null;
  if (styleSheet.href &&
      Services.io.extractScheme(this.styleSheet.href) == "file") {
    this._styleSheetFilePath = this.styleSheet.href;
  }

  this._onPropertyChange = this._onPropertyChange.bind(this);
  this._onError = this._onError.bind(this);
  this._onMediaRuleMatchesChange = this._onMediaRuleMatchesChange.bind(this);
  this._onMediaRulesChanged = this._onMediaRulesChanged.bind(this)
  this.checkLinkedFileForChanges = this.checkLinkedFileForChanges.bind(this);
  this.markLinkedFileBroken = this.markLinkedFileBroken.bind(this);
  this.saveToFile = this.saveToFile.bind(this);
  this.updateStyleSheet = this.updateStyleSheet.bind(this);
  this._onMouseMove = this._onMouseMove.bind(this);

  this._focusOnSourceEditorReady = false;
  this.cssSheet.on("property-change", this._onPropertyChange);
  this.styleSheet.on("error", this._onError);
  this.mediaRules = [];
  if (this.cssSheet.getMediaRules) {
    this.cssSheet.getMediaRules().then(this._onMediaRulesChanged);
  }
  this.cssSheet.on("media-rules-changed", this._onMediaRulesChanged);
  this.savedFile = file;
  this.linkCSSFile();
}

StyleSheetEditor.prototype = {
  /**
   * Whether there are unsaved changes in the editor
   */
  get unsaved() {
    return this.sourceEditor && !this.sourceEditor.isClean();
  },

  /**
   * Whether the editor is for a stylesheet created by the user
   * through the style editor UI.
   */
  get isNew() {
    return this._isNew;
  },

  /**
   * The style sheet or the generated style sheet for this source if it's an
   * original source.
   */
  get cssSheet() {
    if (this.styleSheet.isOriginalSource) {
      return this.styleSheet.relatedStyleSheet;
    }
    return this.styleSheet;
  },

  get savedFile() {
    return this._savedFile;
  },

  set savedFile(name) {
    this._savedFile = name;

    this.linkCSSFile();
  },

  /**
   * Get a user-friendly name for the style sheet.
   *
   * @return string
   */
  get friendlyName() {
    if (this.savedFile) {
      return this.savedFile.leafName;
    }

    if (this._isNew) {
      let index = this.styleSheet.styleSheetIndex + 1;
      return _("newStyleSheet", index);
    }

    if (!this.styleSheet.href) {
      let index = this.styleSheet.styleSheetIndex + 1;
      return _("inlineStyleSheet", index);
    }

    if (!this._friendlyName) {
      let sheetURI = this.styleSheet.href;
      this._friendlyName = CssLogic.shortSource({ href: sheetURI });
      try {
        this._friendlyName = decodeURI(this._friendlyName);
      } catch (ex) {
      }
    }
    return this._friendlyName;
  },

  /**
   * If this is an original source, get the path of the CSS file it generated.
   */
  linkCSSFile: function() {
    if (!this.styleSheet.isOriginalSource) {
      return;
    }

    let relatedSheet = this.styleSheet.relatedStyleSheet;

    let path;
    let href = removeQuery(relatedSheet.href);
    let uri = NetUtil.newURI(href);

    if (uri.scheme == "file") {
      let file = uri.QueryInterface(Ci.nsIFileURL).file;
      path = file.path;
    }
    else if (this.savedFile) {
      let origHref = removeQuery(this.styleSheet.href);
      let origUri = NetUtil.newURI(origHref);
      path = findLinkedFilePath(uri, origUri, this.savedFile);
    }
    else {
      // we can't determine path to generated file on disk
      return;
    }

    if (this.linkedCSSFile == path) {
      return;
    }

    this.linkedCSSFile = path;

    this.linkedCSSFileError = null;

    // save last file change time so we can compare when we check for changes.
    OS.File.stat(path).then((info) => {
      this._fileModDate = info.lastModificationDate.getTime();
    }, this.markLinkedFileBroken);

    this.emit("linked-css-file");
  },

  /**
   * Start fetching the full text source for this editor's sheet.
   */
  fetchSource: function(callback) {
    return this.styleSheet.getText().then((longStr) => {
      longStr.string().then((source) => {
        let ruleCount = this.styleSheet.ruleCount;
        if (!this.styleSheet.isOriginalSource) {
          source = CssLogic.prettifyCSS(source, ruleCount);
        }
        this._state.text = source;
        this.sourceLoaded = true;

        if (callback) {
          callback(source);
        }
        return source;
      });
    }, e => {
      this.emit("error", { key: LOAD_ERROR, append: this.styleSheet.href });
      throw e;
    })
  },

  /**
   * Add markup to a region. UNUSED_CLASS is added to specified lines
   * @param region An object shaped like
   *   {
   *     start: { line: L1, column: C1 },
   *     end: { line: L2, column: C2 }    // optional
   *   }
   */
  addUnusedRegion: function(region) {
    this.sourceEditor.addLineClass(region.start.line - 1, UNUSED_CLASS);
    if (region.end) {
      for (let i = region.start.line; i <= region.end.line; i++) {
        this.sourceEditor.addLineClass(i - 1, UNUSED_CLASS);
      }
    }
  },

  /**
   * As addUnusedRegion except that it takes an array of regions
   */
  addUnusedRegions: function(regions) {
    for (let region of regions) {
      this.addUnusedRegion(region);
    }
  },

  /**
   * Remove all the unused markup regions added by addUnusedRegion
   */
  removeAllUnusedRegions: function() {
    for (let i = 0; i < this.sourceEditor.lineCount(); i++) {
      this.sourceEditor.removeLineClass(i, UNUSED_CLASS);
    }
  },

  /**
   * Forward property-change event from stylesheet.
   *
   * @param  {string} event
   *         Event type
   * @param  {string} property
   *         Property that has changed on sheet
   */
  _onPropertyChange: function(property, value) {
    this.emit("property-change", property, value);
  },

  /**
   * Handles changes to the list of @media rules in the stylesheet.
   * Emits 'media-rules-changed' if the list has changed.
   *
   * @param  {array} rules
   *         Array of MediaRuleFronts for new media rules of sheet.
   */
  _onMediaRulesChanged: function(rules) {
    if (!rules.length && !this.mediaRules.length) {
      return;
    }
    for (let rule of this.mediaRules) {
      rule.off("matches-change", this._onMediaRuleMatchesChange);
      rule.destroy();
    }
    this.mediaRules = rules;

    for (let rule of rules) {
      rule.on("matches-change", this._onMediaRuleMatchesChange);
    }
    this.emit("media-rules-changed", rules);
  },

  /**
   * Forward media-rules-changed event from stylesheet.
   */
  _onMediaRuleMatchesChange: function() {
    this.emit("media-rules-changed", this.mediaRules);
  },

  /**
   * Forward error event from stylesheet.
   *
   * @param  {string} event
   *         Event type
   * @param  {string} errorCode
   */
  _onError: function(event, data) {
    this.emit("error", data);
  },

  /**
   * Create source editor and load state into it.
   * @param  {DOMElement} inputElement
   *         Element to load source editor in
   *
   * @return {Promise}
   *         Promise that will resolve when the style editor is loaded.
   */
  load: function(inputElement) {
    this._inputElement = inputElement;

    let config = {
      value: this._state.text,
      lineNumbers: true,
      mode: Editor.modes.css,
      readOnly: false,
      autoCloseBrackets: "{}()[]",
      extraKeys: this._getKeyBindings(),
      contextMenu: "sourceEditorContextMenu",
      autocomplete: Services.prefs.getBoolPref(AUTOCOMPLETION_PREF),
      autocompleteOpts: { walker: this.walker }
    };
    let sourceEditor = this._sourceEditor = new Editor(config);

    sourceEditor.on("dirty-change", this._onPropertyChange);

    return sourceEditor.appendTo(inputElement).then(() => {
      sourceEditor.on("save", this.saveToFile);

      if (this.styleSheet.update) {
        sourceEditor.on("change", this.updateStyleSheet);
      }

      this.sourceEditor = sourceEditor;

      if (this._focusOnSourceEditorReady) {
        this._focusOnSourceEditorReady = false;
        sourceEditor.focus();
      }

      sourceEditor.setFirstVisibleLine(this._state.topIndex);
      sourceEditor.setSelection(this._state.selection.start,
                                this._state.selection.end);

      if (this.highlighter && this.walker) {
        sourceEditor.container.addEventListener("mousemove", this._onMouseMove);
      }

      this.emit("source-editor-load");
    });
  },

  /**
   * Get the source editor for this editor.
   *
   * @return {Promise}
   *         Promise that will resolve with the editor.
   */
  getSourceEditor: function() {
    let deferred = promise.defer();

    if (this.sourceEditor) {
      return promise.resolve(this);
    }
    this.on("source-editor-load", () => {
      deferred.resolve(this);
    });
    return deferred.promise;
  },

  /**
   * Focus the Style Editor input.
   */
  focus: function() {
    if (this.sourceEditor) {
      this.sourceEditor.focus();
    } else {
      this._focusOnSourceEditorReady = true;
    }
  },

  /**
   * Event handler for when the editor is shown.
   */
  onShow: function() {
    if (this.sourceEditor) {
      this.sourceEditor.setFirstVisibleLine(this._state.topIndex);
    }
    this.focus();
  },

  /**
   * Toggled the disabled state of the underlying stylesheet.
   */
  toggleDisabled: function() {
    this.styleSheet.toggleDisabled();
  },

  /**
   * Queue a throttled task to update the live style sheet.
   *
   * @param boolean immediate
   *        Optional. If true the update is performed immediately.
   */
  updateStyleSheet: function(immediate) {
    if (this._updateTask) {
      // cancel previous queued task not executed within throttle delay
      this._window.clearTimeout(this._updateTask);
    }

    if (immediate) {
      this._updateStyleSheet();
    } else {
      this._updateTask = this._window.setTimeout(this._updateStyleSheet.bind(this),
                                           UPDATE_STYLESHEET_THROTTLE_DELAY);
    }
  },

  /**
   * Update live style sheet according to modifications.
   */
  _updateStyleSheet: function() {
    if (this.styleSheet.disabled) {
      return;  // TODO: do we want to do this?
    }

    this._updateTask = null; // reset only if we actually perform an update
                             // (stylesheet is enabled) so that 'missed' updates
                             // while the stylesheet is disabled can be performed
                             // when it is enabled back. @see enableStylesheet

    if (this.sourceEditor) {
      this._state.text = this.sourceEditor.getText();
    }

    let transitionsEnabled = Services.prefs.getBoolPref(TRANSITION_PREF);

    this.styleSheet.update(this._state.text, transitionsEnabled);
  },

  /**
   * Handle mousemove events, calling _highlightSelectorAt after a delay only
   * and reseting the delay everytime.
   */
  _onMouseMove: function(e) {
    this.highlighter.hide();

    if (this.mouseMoveTimeout) {
      this._window.clearTimeout(this.mouseMoveTimeout);
      this.mouseMoveTimeout = null;
    }

    this.mouseMoveTimeout = this._window.setTimeout(() => {
      this._highlightSelectorAt(e.clientX, e.clientY);
    }, SELECTOR_HIGHLIGHT_TIMEOUT);
  },

  /**
   * Highlight nodes matching the selector found at coordinates x,y in the
   * editor, if any.
   *
   * @param {Number} x
   * @param {Number} y
   */
  _highlightSelectorAt: Task.async(function*(x, y) {
    // Need to catch parsing exceptions as long as bug 1051900 isn't fixed
    let info;
    try {
      let pos = this.sourceEditor.getPositionFromCoords({left: x, top: y});
      info = this.sourceEditor.getInfoAt(pos);
    } catch (e) {}
    if (!info || info.state !== "selector") {
      return;
    }

    let node = yield this.walker.getStyleSheetOwnerNode(this.styleSheet.actorID);
    yield this.highlighter.show(node, {
      selector: info.selector,
      hideInfoBar: true,
      showOnly: "border",
      region: "border"
    });

    this.emit("node-highlighted");
  }),

  /**
   * Save the editor contents into a file and set savedFile property.
   * A file picker UI will open if file is not set and editor is not headless.
   *
   * @param mixed file
   *        Optional nsIFile or string representing the filename to save in the
   *        background, no UI will be displayed.
   *        If not specified, the original style sheet URI is used.
   *        To implement 'Save' instead of 'Save as', you can pass savedFile here.
   * @param function(nsIFile aFile) callback
   *        Optional callback called when the operation has finished.
   *        aFile has the nsIFile object for saved file or null if the operation
   *        has failed or has been canceled by the user.
   * @see savedFile
   */
  saveToFile: function(file, callback) {
    let onFile = (returnFile) => {
      if (!returnFile) {
        if (callback) {
          callback(null);
        }
        return;
      }

      if (this.sourceEditor) {
        this._state.text = this.sourceEditor.getText();
      }

      let ostream = FileUtils.openSafeFileOutputStream(returnFile);
      let converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
                        .createInstance(Ci.nsIScriptableUnicodeConverter);
      converter.charset = "UTF-8";
      let istream = converter.convertToInputStream(this._state.text);

      NetUtil.asyncCopy(istream, ostream, (status) => {
        if (!Components.isSuccessCode(status)) {
          if (callback) {
            callback(null);
          }
          this.emit("error", { key: SAVE_ERROR });
          return;
        }
        FileUtils.closeSafeFileOutputStream(ostream);

        this.onFileSaved(returnFile);

        if (callback) {
          callback(returnFile);
        }
      });
    };

    let defaultName;
    if (this._friendlyName) {
      defaultName = OS.Path.basename(this._friendlyName);
    }
    showFilePicker(file || this._styleSheetFilePath, true, this._window,
                   onFile, defaultName);
  },

  /**
   * Called when this source has been successfully saved to disk.
   */
  onFileSaved: function(returnFile) {
    this._friendlyName = null;
    this.savedFile = returnFile;

    if (this.sourceEditor) {
      this.sourceEditor.setClean();
    }

    this.emit("property-change");

    // TODO: replace with file watching
    this._modCheckCount = 0;
    this._window.clearTimeout(this._timeout);

    if (this.linkedCSSFile && !this.linkedCSSFileError) {
      this._timeout = this._window.setTimeout(this.checkLinkedFileForChanges,
                                              CHECK_LINKED_SHEET_DELAY);
    }
  },

  /**
   * Check to see if our linked CSS file has changed on disk, and
   * if so, update the live style sheet.
   */
  checkLinkedFileForChanges: function() {
    OS.File.stat(this.linkedCSSFile).then((info) => {
      let lastChange = info.lastModificationDate.getTime();

      if (this._fileModDate && lastChange != this._fileModDate) {
        this._fileModDate = lastChange;
        this._modCheckCount = 0;

        this.updateLinkedStyleSheet();
        return;
      }

      if (++this._modCheckCount > MAX_CHECK_COUNT) {
        this.updateLinkedStyleSheet();
        return;
      }

      // try again in a bit
      this._timeout = this._window.setTimeout(this.checkLinkedFileForChanges,
                                              CHECK_LINKED_SHEET_DELAY);
    }, this.markLinkedFileBroken);
  },

  /**
   * Notify that the linked CSS file (if this is an original source)
   * doesn't exist on disk in the place we think it does.
   *
   * @param string error
   *        The error we got when trying to access the file.
   */
  markLinkedFileBroken: function(error) {
    this.linkedCSSFileError = error || true;
    this.emit("linked-css-file-error");

    error += " querying " + this.linkedCSSFile +
             " original source location: " + this.savedFile.path
    Cu.reportError(error);
  },

  /**
   * For original sources (e.g. Sass files). Fetch contents of linked CSS
   * file from disk and live update the stylesheet object with the contents.
   */
  updateLinkedStyleSheet: function() {
    OS.File.read(this.linkedCSSFile).then((array) => {
      let decoder = new TextDecoder();
      let text = decoder.decode(array);

      let relatedSheet = this.styleSheet.relatedStyleSheet;
      relatedSheet.update(text, true);
    }, this.markLinkedFileBroken);
  },

  /**
    * Retrieve custom key bindings objects as expected by Editor.
    * Editor action names are not displayed to the user.
    *
    * @return {array} key binding objects for the source editor
    */
  _getKeyBindings: function() {
    let bindings = {};

    bindings[Editor.accel(_("saveStyleSheet.commandkey"))] = () => {
      this.saveToFile(this.savedFile);
    };

    bindings["Shift-" + Editor.accel(_("saveStyleSheet.commandkey"))] = () => {
      this.saveToFile();
    };

    bindings["Esc"] = false;

    return bindings;
  },

  /**
   * Clean up for this editor.
   */
  destroy: function() {
    if (this._sourceEditor) {
      this._sourceEditor.off("dirty-change", this._onPropertyChange);
      this._sourceEditor.off("save", this.saveToFile);
      this._sourceEditor.off("change", this.updateStyleSheet);
      if (this.highlighter && this.walker && this._sourceEditor.container) {
        this._sourceEditor.container.removeEventListener("mousemove",
          this._onMouseMove);
      }
      this._sourceEditor.destroy();
    }
    this.cssSheet.off("property-change", this._onPropertyChange);
    this.cssSheet.off("media-rules-changed", this._onMediaRulesChanged);
    this.styleSheet.off("error", this._onError);
  }
}

/**
 * Find a path on disk for a file given it's hosted uri, the uri of the
 * original resource that generated it (e.g. Sass file), and the location of the
 * local file for that source.
 *
 * @param {nsIURI} uri
 *        The uri of the resource
 * @param {nsIURI} origUri
 *        The uri of the original source for the resource
 * @param {nsIFile} file
 *        The local file for the resource on disk
 *
 * @return {string}
 *         The path of original file on disk
 */
function findLinkedFilePath(uri, origUri, file) {
  let { origBranch, branch } = findUnsharedBranches(origUri, uri);
  let project = findProjectPath(file, origBranch);

  let parts = project.concat(branch);
  let path = OS.Path.join.apply(this, parts);

  return path;
}

/**
 * Find the path of a project given a file in the project and its branch
 * off the root. e.g.:
 * /Users/moz/proj/src/a.css" and "src/a.css"
 * would yield ["Users", "moz", "proj"]
 *
 * @param {nsIFile} file
 *        file for that resource on disk
 * @param {array} branch
 *        path parts for branch to chop off file path.
 * @return {array}
 *        array of path parts
 */
function findProjectPath(file, branch) {
  let path = OS.Path.split(file.path).components;

  for (let i = 2; i <= branch.length; i++) {
    // work backwards until we find a differing directory name
    if (path[path.length - i] != branch[branch.length - i]) {
      return path.slice(0, path.length - i + 1);
    }
  }

  // if we don't find a differing directory, just chop off the branch
  return path.slice(0, path.length - branch.length);
}

/**
 * Find the parts of a uri past the root it shares with another uri. e.g:
 * "http://localhost/built/a.scss" and "http://localhost/src/a.css"
 * would yield ["built", "a.scss"] and ["src", "a.css"]
 *
 * @param {nsIURI} origUri
 *        uri to find unshared branch of. Usually is uri for original source.
 * @param {nsIURI} uri
 *        uri to compare against to get a shared root
 * @return {object}
 *         object with 'branch' and 'origBranch' array of path parts for branch
 */
function findUnsharedBranches(origUri, uri) {
  origUri = OS.Path.split(origUri.path).components;
  uri = OS.Path.split(uri.path).components;

  for (let i = 0; i < uri.length - 1; i++) {
    if (uri[i] != origUri[i]) {
      return {
        branch: uri.slice(i),
        origBranch: origUri.slice(i)
      };
    }
  }
  return {
    branch: uri,
    origBranch: origUri
  };
}

/**
 * Remove the query string from a url.
 *
 * @param  {string} href
 *         Url to remove query string from
 * @return {string}
 *         Url without query string
 */
function removeQuery(href) {
  return href.replace(/\?.*/, "");
}