gecko/browser/devtools/styleinspector/computed-view.js

/* -*- Mode: Javascript; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

const {Cc, Ci, Cu} = require("chrome");

let ToolDefinitions = require("main").Tools;
let {CssLogic} = require("devtools/styleinspector/css-logic");
let {ELEMENT_STYLE} = require("devtools/server/actors/styles");
let promise = require("sdk/core/promise");
let {EventEmitter} = require("devtools/shared/event-emitter");
let {colorUtils} = require("devtools/shared/css-color");

Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/PluralForm.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/devtools/Templater.jsm");

let {gDevTools} = Cu.import("resource:///modules/devtools/gDevTools.jsm", {});

const FILTER_CHANGED_TIMEOUT = 300;

const HTML_NS = "http://www.w3.org/1999/xhtml";
const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";

/**
 * Helper for long-running processes that should yield occasionally to
 * the mainloop.
 *
 * @param {Window} aWin
 *        Timeouts will be set on this window when appropriate.
 * @param {Generator} aGenerator
 *        Will iterate this generator.
 * @param {object} aOptions
 *        Options for the update process:
 *          onItem {function} Will be called with the value of each iteration.
 *          onBatch {function} Will be called after each batch of iterations,
 *            before yielding to the main loop.
 *          onDone {function} Will be called when iteration is complete.
 *          onCancel {function} Will be called if the process is canceled.
 *          threshold {int} How long to process before yielding, in ms.
 *
 * @constructor
 */
function UpdateProcess(aWin, aGenerator, aOptions)
{
  this.win = aWin;
  this.iter = _Iterator(aGenerator);
  this.onItem = aOptions.onItem || function() {};
  this.onBatch = aOptions.onBatch || function () {};
  this.onDone = aOptions.onDone || function() {};
  this.onCancel = aOptions.onCancel || function() {};
  this.threshold = aOptions.threshold || 45;

  this.canceled = false;
}

UpdateProcess.prototype = {
  /**
   * Schedule a new batch on the main loop.
   */
  schedule: function UP_schedule()
  {
    if (this.canceled) {
      return;
    }
    this._timeout = this.win.setTimeout(this._timeoutHandler.bind(this), 0);
  },

  /**
   * Cancel the running process.  onItem will not be called again,
   * and onCancel will be called.
   */
  cancel: function UP_cancel()
  {
    if (this._timeout) {
      this.win.clearTimeout(this._timeout);
      this._timeout = 0;
    }
    this.canceled = true;
    this.onCancel();
  },

  _timeoutHandler: function UP_timeoutHandler() {
    this._timeout = null;
    try {
      this._runBatch();
      this.schedule();
    } catch(e) {
      if (e instanceof StopIteration) {
        this.onBatch();
        this.onDone();
        return;
      }
      console.error(e);
      throw e;
    }
  },

  _runBatch: function Y_runBatch()
  {
    let time = Date.now();
    while(!this.canceled) {
      // Continue until iter.next() throws...
      let next = this.iter.next();
      this.onItem(next[1]);
      if ((Date.now() - time) > this.threshold) {
        this.onBatch();
        return;
      }
    }
  }
};

/**
 * CssHtmlTree is a panel that manages the display of a table sorted by style.
 * There should be one instance of CssHtmlTree per style display (of which there
 * will generally only be one).
 *
 * @params {StyleInspector} aStyleInspector The owner of this CssHtmlTree
 * @param {PageStyleFront} aPageStyle
 *        Front for the page style actor that will be providing
 *        the style information.
 *
 * @constructor
 */
function CssHtmlTree(aStyleInspector, aPageStyle)
{
  this.styleWindow = aStyleInspector.window;
  this.styleDocument = aStyleInspector.window.document;
  this.styleInspector = aStyleInspector;
  this.pageStyle = aPageStyle;
  this.propertyViews = [];

  let chromeReg = Cc["@mozilla.org/chrome/chrome-registry;1"].
    getService(Ci.nsIXULChromeRegistry);
  this.getRTLAttr = chromeReg.isLocaleRTL("global") ? "rtl" : "ltr";

  // Create bound methods.
  this.siFocusWindow = this.focusWindow.bind(this);
  this.siBoundCopy = this.computedViewCopy.bind(this);

  this.styleDocument.addEventListener("copy", this.siBoundCopy);
  this.styleDocument.addEventListener("mousedown", this.siFocusWindow);

  // Nodes used in templating
  this.root = this.styleDocument.getElementById("root");
  this.templateRoot = this.styleDocument.getElementById("templateRoot");
  this.propertyContainer = this.styleDocument.getElementById("propertyContainer");

  // No results text.
  this.noResults = this.styleDocument.getElementById("noResults");

  // Refresh panel when color unit changed.
  this._handlePrefChange = this._handlePrefChange.bind(this);
  gDevTools.on("pref-changed", this._handlePrefChange);

  CssHtmlTree.processTemplate(this.templateRoot, this.root, this);

  // The element that we're inspecting, and the document that it comes from.
  this.viewedElement = null;
  this.createStyleViews();
}

/**
 * Memoized lookup of a l10n string from a string bundle.
 * @param {string} aName The key to lookup.
 * @returns A localized version of the given key.
 */
CssHtmlTree.l10n = function CssHtmlTree_l10n(aName)
{
  try {
    return CssHtmlTree._strings.GetStringFromName(aName);
  } catch (ex) {
    Services.console.logStringMessage("Error reading '" + aName + "'");
    throw new Error("l10n error with " + aName);
  }
};

/**
 * Clone the given template node, and process it by resolving ${} references
 * in the template.
 *
 * @param {nsIDOMElement} aTemplate the template note to use.
 * @param {nsIDOMElement} aDestination the destination node where the
 * processed nodes will be displayed.
 * @param {object} aData the data to pass to the template.
 * @param {Boolean} aPreserveDestination If true then the template will be
 * appended to aDestination's content else aDestination.innerHTML will be
 * cleared before the template is appended.
 */
CssHtmlTree.processTemplate = function CssHtmlTree_processTemplate(aTemplate,
                                  aDestination, aData, aPreserveDestination)
{
  if (!aPreserveDestination) {
    aDestination.innerHTML = "";
  }

  // All the templater does is to populate a given DOM tree with the given
  // values, so we need to clone the template first.
  let duplicated = aTemplate.cloneNode(true);

  // See https://github.com/mozilla/domtemplate/blob/master/README.md
  // for docs on the template() function
  template(duplicated, aData, { allowEval: true });
  while (duplicated.firstChild) {
    aDestination.appendChild(duplicated.firstChild);
  }
};

XPCOMUtils.defineLazyGetter(CssHtmlTree, "_strings", function() Services.strings
        .createBundle("chrome://browser/locale/devtools/styleinspector.properties"));

XPCOMUtils.defineLazyGetter(this, "clipboardHelper", function() {
  return Cc["@mozilla.org/widget/clipboardhelper;1"].
    getService(Ci.nsIClipboardHelper);
});

CssHtmlTree.prototype = {
  // Cache the list of properties that match the selected element.
  _matchedProperties: null,

  // Used for cancelling timeouts in the style filter.
  _filterChangedTimeout: null,

  // The search filter
  searchField: null,

  // Reference to the "Include browser styles" checkbox.
  includeBrowserStylesCheckbox: null,

  // Holds the ID of the panelRefresh timeout.
  _panelRefreshTimeout: null,

  // Toggle for zebra striping
  _darkStripe: true,

  // Number of visible properties
  numVisibleProperties: 0,

  setPageStyle: function(pageStyle) {
    this.pageStyle = pageStyle;
  },

  get includeBrowserStyles()
  {
    return this.includeBrowserStylesCheckbox.checked;
  },

  _handlePrefChange: function(event, data) {
    if (data.pref == "devtools.defaultColorUnit" && this._computed) {
      this.refreshPanel();
    }
  },

  /**
   * Update the highlighted element. The CssHtmlTree panel will show the style
   * information for the given element.
   * @param {nsIDOMElement} aElement The highlighted node to get styles for.
   *
   * @returns a promise that will be resolved when highlighting is complete.
   */
  highlight: function(aElement) {
    if (!aElement) {
      if (this._refreshProcess) {
        this._refreshProcess.cancel();
      }
      return promise.resolve(undefined);
    }

    if (aElement === this.viewedElement) {
      return promise.resolve(undefined);
    }

    this.viewedElement = aElement;

    this.refreshSourceFilter();
    return this.refreshPanel();
  },

  _createPropertyViews: function()
  {
    if (this._createViewsPromise) {
      return this._createViewsPromise;
    }

    let deferred = promise.defer();
    this._createViewsPromise = deferred.promise;

    this.refreshSourceFilter();
    this.numVisibleProperties = 0;
    let fragment = this.styleDocument.createDocumentFragment();

    this._createViewsProcess = new UpdateProcess(this.styleWindow, CssHtmlTree.propertyNames, {
      onItem: (aPropertyName) => {
        // Per-item callback.
        let propView = new PropertyView(this, aPropertyName);
        fragment.appendChild(propView.buildMain());
        fragment.appendChild(propView.buildSelectorContainer());

        if (propView.visible) {
          this.numVisibleProperties++;
        }
        this.propertyViews.push(propView);
      },
      onCancel: () => {
        deferred.reject("_createPropertyViews cancelled");
      },
      onDone: () => {
        // Completed callback.
        this.propertyContainer.appendChild(fragment);
        this.noResults.hidden = this.numVisibleProperties > 0;
        deferred.resolve(undefined);
      }
    });

    this._createViewsProcess.schedule();
    return deferred.promise;
  },

  /**
   * Refresh the panel content.
   */
  refreshPanel: function CssHtmlTree_refreshPanel()
  {
    return promise.all([
      this._createPropertyViews(),
      this.pageStyle.getComputed(this.viewedElement, {
        filter: this._sourceFilter,
        onlyMatched: !this.includeBrowserStyles,
        markMatched: true
      })
    ]).then(([createViews, computed]) => {
      this._matchedProperties = new Set;
      for (let name in computed) {
        if (computed[name].matched) {
          this._matchedProperties.add(name);
        }
      }
      this._computed = computed;

      if (this._refreshProcess) {
        this._refreshProcess.cancel();
      }

      this.noResults.hidden = true;

      // Reset visible property count
      this.numVisibleProperties = 0;

      // Reset zebra striping.
      this._darkStripe = true;

      let display = this.propertyContainer.style.display;

      let deferred = promise.defer();
      this._refreshProcess = new UpdateProcess(this.styleWindow, this.propertyViews, {
        onItem: (aPropView) => {
          aPropView.refresh();
        },
        onCancel: () => {
          deferred.reject("refresh cancelled");
        },
        onDone: () => {
          this._refreshProcess = null;
          this.noResults.hidden = this.numVisibleProperties > 0;
          this.styleInspector.inspector.emit("computed-view-refreshed");
          deferred.resolve(undefined);
        }
      });
      this._refreshProcess.schedule();
      return deferred.promise;
    }).then(null, (err) => console.error(err));
  },

  /**
   * Called when the user enters a search term.
   *
   * @param {Event} aEvent the DOM Event object.
   */
  filterChanged: function CssHtmlTree_filterChanged(aEvent)
  {
    let win = this.styleWindow;

    if (this._filterChangedTimeout) {
      win.clearTimeout(this._filterChangedTimeout);
    }

    this._filterChangedTimeout = win.setTimeout(function() {
      this.refreshPanel();
      this._filterChangeTimeout = null;
    }.bind(this), FILTER_CHANGED_TIMEOUT);
  },

  /**
   * The change event handler for the includeBrowserStyles checkbox.
   *
   * @param {Event} aEvent the DOM Event object.
   */
  includeBrowserStylesChanged:
  function CssHtmltree_includeBrowserStylesChanged(aEvent)
  {
    this.refreshSourceFilter();
    this.refreshPanel();
  },

  /**
   * When includeBrowserStyles.checked is false we only display properties that
   * have matched selectors and have been included by the document or one of the
   * document's stylesheets. If .checked is false we display all properties
   * including those that come from UA stylesheets.
   */
  refreshSourceFilter: function CssHtmlTree_setSourceFilter()
  {
    this._matchedProperties = null;
    this._sourceFilter = this.includeBrowserStyles ?
                                 CssLogic.FILTER.UA :
                                 CssLogic.FILTER.USER;
  },

  /**
   * The CSS as displayed by the UI.
   */
  createStyleViews: function CssHtmlTree_createStyleViews()
  {
    if (CssHtmlTree.propertyNames) {
      return;
    }

    CssHtmlTree.propertyNames = [];

    // Here we build and cache a list of css properties supported by the browser
    // We could use any element but let's use the main document's root element
    let styles = this.styleWindow.getComputedStyle(this.styleDocument.documentElement);
    let mozProps = [];
    for (let i = 0, numStyles = styles.length; i < numStyles; i++) {
      let prop = styles.item(i);
      if (prop.charAt(0) == "-") {
        mozProps.push(prop);
      } else {
        CssHtmlTree.propertyNames.push(prop);
      }
    }

    CssHtmlTree.propertyNames.sort();
    CssHtmlTree.propertyNames.push.apply(CssHtmlTree.propertyNames,
      mozProps.sort());

    this._createPropertyViews();
  },

  /**
   * Get a set of properties that have matched selectors.
   *
   * @return {Set} If a property name is in the set, it has matching selectors.
   */
  get matchedProperties()
  {
    return this._matchedProperties || new Set;
  },

  /**
   * Focus the window on mousedown.
   *
   * @param aEvent The event object
   */
  focusWindow: function si_focusWindow(aEvent)
  {
    let win = this.styleDocument.defaultView;
    win.focus();
  },

  /**
   * Copy selected text.
   *
   * @param aEvent The event object
   */
  computedViewCopy: function si_computedViewCopy(aEvent)
  {
    let win = this.styleDocument.defaultView;
    let text = win.getSelection().toString();

    // Tidy up block headings by moving CSS property names and their values onto
    // the same line and inserting a colon between them.
    text = text.replace(/(.+)\r\n(.+)/g, "$1: $2;");
    text = text.replace(/(.+)\n(.+)/g, "$1: $2;");

    let outerDoc = this.styleInspector.outerIFrame.ownerDocument;
    clipboardHelper.copyString(text, outerDoc);

    if (aEvent) {
      aEvent.preventDefault();
    }
  },

  /**
   * Destructor for CssHtmlTree.
   */
  destroy: function CssHtmlTree_destroy()
  {
    delete this.viewedElement;

    // Remove event listeners
    this.includeBrowserStylesCheckbox.removeEventListener("command",
      this.includeBrowserStylesChanged);
    this.searchField.removeEventListener("command", this.filterChanged);
    gDevTools.off("pref-changed", this._handlePrefChange);

    // Cancel tree construction
    if (this._createViewsProcess) {
      this._createViewsProcess.cancel();
    }
    if (this._refreshProcess) {
      this._refreshProcess.cancel();
    }

    // Remove context menu
    let outerDoc = this.styleInspector.outerIFrame.ownerDocument;
    let menu = outerDoc.querySelector("#computed-view-context-menu");
    if (menu) {
      // Copy selected
      let menuitem = outerDoc.querySelector("#computed-view-copy");
      menuitem.removeEventListener("command", this.siBoundCopy);

      // Copy property
      menuitem = outerDoc.querySelector("#computed-view-copy-declaration");
      menuitem.removeEventListener("command", this.siBoundCopyDeclaration);

      // Copy property name
      menuitem = outerDoc.querySelector("#computed-view-copy-property");
      menuitem.removeEventListener("command", this.siBoundCopyProperty);

      // Copy property value
      menuitem = outerDoc.querySelector("#computed-view-copy-property-value");
      menuitem.removeEventListener("command", this.siBoundCopyPropertyValue);

      menu.removeEventListener("popupshowing", this.siBoundMenuUpdate);
      menu.parentNode.removeChild(menu);
    }

    // Remove bound listeners
    this.styleDocument.removeEventListener("copy", this.siBoundCopy);
    this.styleDocument.removeEventListener("mousedown", this.siFocusWindow);

    // Nodes used in templating
    delete this.root;
    delete this.propertyContainer;
    delete this.panel;

    // The document in which we display the results (csshtmltree.xul).
    delete this.styleDocument;

    // The element that we're inspecting, and the document that it comes from.
    delete this.propertyViews;
    delete this.styleWindow;
    delete this.styleDocument;
    delete this.styleInspector;
  },
};

function PropertyInfo(aTree, aName) {
  this.tree = aTree;
  this.name = aName;
}
PropertyInfo.prototype = {
  get value() {
    if (this.tree._computed) {
      let value = this.tree._computed[this.name].value;
      return colorUtils.processCSSString(value);
    }
  }
};

/**
 * A container to give easy access to property data from the template engine.
 *
 * @constructor
 * @param {CssHtmlTree} aTree the CssHtmlTree instance we are working with.
 * @param {string} aName the CSS property name for which this PropertyView
 * instance will render the rules.
 */
function PropertyView(aTree, aName)
{
  this.tree = aTree;
  this.name = aName;
  this.getRTLAttr = aTree.getRTLAttr;

  this.link = "https://developer.mozilla.org/CSS/" + aName;

  this.templateMatchedSelectors = aTree.styleDocument.getElementById("templateMatchedSelectors");
  this._propertyInfo = new PropertyInfo(aTree, aName);
}

PropertyView.prototype = {
  // The parent element which contains the open attribute
  element: null,

  // Property header node
  propertyHeader: null,

  // Destination for property names
  nameNode: null,

  // Destination for property values
  valueNode: null,

  // Are matched rules expanded?
  matchedExpanded: false,

  // Matched selector container
  matchedSelectorsContainer: null,

  // Matched selector expando
  matchedExpander: null,

  // Cache for matched selector views
  _matchedSelectorViews: null,

  // The previously selected element used for the selector view caches
  prevViewedElement: null,

  /**
   * Get the computed style for the current property.
   *
   * @return {string} the computed style for the current property of the
   * currently highlighted element.
   */
  get value()
  {
    return this.propertyInfo.value;
  },

  /**
   * An easy way to access the CssPropertyInfo behind this PropertyView.
   */
  get propertyInfo()
  {
    return this._propertyInfo;
  },

  /**
   * Does the property have any matched selectors?
   */
  get hasMatchedSelectors()
  {
    return this.tree.matchedProperties.has(this.name);
  },

  /**
   * Should this property be visible?
   */
  get visible()
  {
    if (!this.tree.includeBrowserStyles && !this.hasMatchedSelectors) {
      return false;
    }

    let searchTerm = this.tree.searchField.value.toLowerCase();
    if (searchTerm && this.name.toLowerCase().indexOf(searchTerm) == -1 &&
      this.value.toLowerCase().indexOf(searchTerm) == -1) {
      return false;
    }

    return true;
  },

  /**
   * Returns the className that should be assigned to the propertyView.
   *
   * @return string
   */
  get propertyHeaderClassName()
  {
    if (this.visible) {
      this.tree._darkStripe = !this.tree._darkStripe;
      let darkValue = this.tree._darkStripe ?
                      "property-view theme-bg-darker" : "property-view";
      return darkValue;
    }
    return "property-view-hidden";
  },

  /**
   * Returns the className that should be assigned to the propertyView content
   * container.
   * @return string
   */
  get propertyContentClassName()
  {
    if (this.visible) {
      let darkValue = this.tree._darkStripe ?
                      "property-content theme-bg-darker" : "property-content";
      return darkValue;
    }
    return "property-content-hidden";
  },

  buildMain: function PropertyView_buildMain()
  {
    let doc = this.tree.styleDocument;
    this.element = doc.createElementNS(HTML_NS, "div");
    this.element.setAttribute("class", this.propertyHeaderClassName);

    this.matchedExpander = doc.createElementNS(HTML_NS, "div");
    this.matchedExpander.className = "expander theme-twisty";
    this.matchedExpander.setAttribute("tabindex", "0");
    this.matchedExpander.addEventListener("click",
      this.matchedExpanderClick.bind(this), false);
    this.matchedExpander.addEventListener("keydown", function(aEvent) {
      let keyEvent = Ci.nsIDOMKeyEvent;
      if (aEvent.keyCode == keyEvent.DOM_VK_F1) {
        this.mdnLinkClick();
      }
      if (aEvent.keyCode == keyEvent.DOM_VK_RETURN ||
        aEvent.keyCode == keyEvent.DOM_VK_SPACE) {
        this.matchedExpanderClick(aEvent);
      }
    }.bind(this), false);
    this.element.appendChild(this.matchedExpander);

    this.nameNode = doc.createElementNS(HTML_NS, "div");
    this.element.appendChild(this.nameNode);
    this.nameNode.setAttribute("class", "property-name theme-fg-color5");
    this.nameNode.textContent = this.nameNode.title = this.name;
    this.nameNode.addEventListener("click", function(aEvent) {
      this.matchedExpander.focus();
    }.bind(this), false);

    this.valueNode = doc.createElementNS(HTML_NS, "div");
    this.element.appendChild(this.valueNode);
    this.valueNode.setAttribute("class", "property-value theme-fg-color1");
    this.valueNode.setAttribute("dir", "ltr");
    this.valueNode.textContent = this.valueNode.title = this.value;

    return this.element;
  },

  buildSelectorContainer: function PropertyView_buildSelectorContainer()
  {
    let doc = this.tree.styleDocument;
    let element = doc.createElementNS(HTML_NS, "div");
    element.setAttribute("class", this.propertyContentClassName);
    this.matchedSelectorsContainer = doc.createElementNS(HTML_NS, "div");
    this.matchedSelectorsContainer.setAttribute("class", "matchedselectors");
    element.appendChild(this.matchedSelectorsContainer);

    return element;
  },

  /**
   * Refresh the panel's CSS property value.
   */
  refresh: function PropertyView_refresh()
  {
    this.element.className = this.propertyHeaderClassName;
    this.element.nextElementSibling.className = this.propertyContentClassName;

    if (this.prevViewedElement != this.tree.viewedElement) {
      this._matchedSelectorViews = null;
      this.prevViewedElement = this.tree.viewedElement;
    }

    if (!this.tree.viewedElement || !this.visible) {
      this.valueNode.textContent = this.valueNode.title = "";
      this.matchedSelectorsContainer.parentNode.hidden = true;
      this.matchedSelectorsContainer.textContent = "";
      this.matchedExpander.removeAttribute("open");
      return;
    }

    this.tree.numVisibleProperties++;
    this.valueNode.textContent = this.valueNode.title = this.propertyInfo.value;
    this.refreshMatchedSelectors();
  },

  /**
   * Refresh the panel matched rules.
   */
  refreshMatchedSelectors: function PropertyView_refreshMatchedSelectors()
  {
    let hasMatchedSelectors = this.hasMatchedSelectors;
    this.matchedSelectorsContainer.parentNode.hidden = !hasMatchedSelectors;

    if (hasMatchedSelectors) {
      this.matchedExpander.classList.add("expandable");
    } else {
      this.matchedExpander.classList.remove("expandable");
    }

    if (this.matchedExpanded && hasMatchedSelectors) {
      return this.tree.pageStyle.getMatchedSelectors(this.tree.viewedElement, this.name).then(matched => {
        if (!this.matchedExpanded) {
          return;
        }

        this._matchedSelectorResponse = matched;
        CssHtmlTree.processTemplate(this.templateMatchedSelectors,
          this.matchedSelectorsContainer, this);
        this.matchedExpander.setAttribute("open", "");
        this.tree.styleInspector.inspector.emit("computed-view-property-expanded");
      }).then(null, console.error);
    } else {
      this.matchedSelectorsContainer.innerHTML = "";
      this.matchedExpander.removeAttribute("open");
      return promise.resolve(undefined);
    }
  },

  get matchedSelectors()
  {
    return this._matchedSelectorResponse;
  },

  /**
   * Provide access to the matched SelectorViews that we are currently
   * displaying.
   */
  get matchedSelectorViews()
  {
    if (!this._matchedSelectorViews) {
      this._matchedSelectorViews = [];
      this._matchedSelectorResponse.forEach(
        function matchedSelectorViews_convert(aSelectorInfo) {
          this._matchedSelectorViews.push(new SelectorView(this.tree, aSelectorInfo));
        }, this);
    }

    return this._matchedSelectorViews;
  },

  /**
   * The action when a user expands matched selectors.
   *
   * @param {Event} aEvent Used to determine the class name of the targets click
   * event.
   */
  matchedExpanderClick: function PropertyView_matchedExpanderClick(aEvent)
  {
    this.matchedExpanded = !this.matchedExpanded;
    this.refreshMatchedSelectors();
    aEvent.preventDefault();
  },

  /**
   * The action when a user clicks on the MDN help link for a property.
   */
  mdnLinkClick: function PropertyView_mdnLinkClick(aEvent)
  {
    let inspector = this.tree.styleInspector.inspector;

    if (inspector.target.tab) {
      let browserWin = inspector.target.tab.ownerDocument.defaultView;
      browserWin.openUILinkIn(this.link, "tab");
    }
    aEvent.preventDefault();
  },
};

/**
 * A container to view us easy access to display data from a CssRule
 * @param CssHtmlTree aTree, the owning CssHtmlTree
 * @param aSelectorInfo
 */
function SelectorView(aTree, aSelectorInfo)
{
  this.tree = aTree;
  this.selectorInfo = aSelectorInfo;
  this._cacheStatusNames();

  let rule = this.selectorInfo.rule;
  if (rule && rule.parentStyleSheet) {
    this.sheet = rule.parentStyleSheet;
    this.source = CssLogic.shortSource(this.sheet) + ":" + rule.line;
  } else {
    this.source = CssLogic.l10n("rule.sourceElement");
    this.href = "#";
  }
}

/**
 * Decode for cssInfo.rule.status
 * @see SelectorView.prototype._cacheStatusNames
 * @see CssLogic.STATUS
 */
SelectorView.STATUS_NAMES = [
  // "Parent Match", "Matched", "Best Match"
];

SelectorView.CLASS_NAMES = [
  "parentmatch", "matched", "bestmatch"
];

SelectorView.prototype = {
  /**
   * Cache localized status names.
   *
   * These statuses are localized inside the styleinspector.properties string
   * bundle.
   * @see css-logic.js - the CssLogic.STATUS array.
   *
   * @return {void}
   */
  _cacheStatusNames: function SelectorView_cacheStatusNames()
  {
    if (SelectorView.STATUS_NAMES.length) {
      return;
    }

    for (let status in CssLogic.STATUS) {
      let i = CssLogic.STATUS[status];
      if (i > CssLogic.STATUS.UNMATCHED) {
        let value = CssHtmlTree.l10n("rule.status." + status);
        // Replace normal spaces with non-breaking spaces
        SelectorView.STATUS_NAMES[i] = value.replace(/ /g, '\u00A0');
      }
    }
  },

  /**
   * A localized version of cssRule.status
   */
  get statusText()
  {
    return SelectorView.STATUS_NAMES[this.selectorInfo.status];
  },

  /**
   * Get class name for selector depending on status
   */
  get statusClass()
  {
    return SelectorView.CLASS_NAMES[this.selectorInfo.status - 1];
  },

  get href()
  {
    if (this._href) {
      return this._href;
    }
    let sheet = this.selectorInfo.rule.parentStyleSheet;
    this._href = sheet ? sheet.href : "#";
    return this._href;
  },

  get sourceText()
  {
    return this.selectorInfo.sourceText;
  },


  get value()
  {
    let val = this.selectorInfo.value;
    return colorUtils.processCSSString(val);
  },

  maybeOpenStyleEditor: function(aEvent)
  {
    let keyEvent = Ci.nsIDOMKeyEvent;
    if (aEvent.keyCode == keyEvent.DOM_VK_RETURN) {
      this.openStyleEditor();
    }
  },

  /**
   * When a css link is clicked this method is called in order to either:
   *   1. Open the link in view source (for chrome stylesheets).
   *   2. Open the link in the style editor.
   *
   *   We can only view stylesheets contained in document.styleSheets inside the
   *   style editor.
   *
   * @param aEvent The click event
   */
  openStyleEditor: function(aEvent)
  {
    let inspector = this.tree.styleInspector.inspector;
    let rule = this.selectorInfo.rule;
    let line = rule.line || 0;

    // The style editor can only display stylesheets coming from content because
    // chrome stylesheets are not listed in the editor's stylesheet selector.
    //
    // If the stylesheet is a content stylesheet we send it to the style
    // editor else we display it in the view source window.
    //

    let href = rule.href;
    let sheet = rule.parentStyleSheet;
    if (sheet && href && !sheet.isSystem) {
      let target = inspector.target;
      if (ToolDefinitions.styleEditor.isTargetSupported(target)) {
        gDevTools.showToolbox(target, "styleeditor").then(function(toolbox) {
          toolbox.getCurrentPanel().selectStyleSheet(href, line);
        });
      }
      return;
    }

    let contentDoc = null;
    let rawNode = this.tree.viewedElement.rawNode();
    if (rawNode) {
      contentDoc = rawNode.ownerDocument;
    }

    let viewSourceUtils = inspector.viewSourceUtils;
    viewSourceUtils.viewSource(href, null, contentDoc, line);
  }
};

exports.CssHtmlTree = CssHtmlTree;
exports.PropertyView = PropertyView;