Finder.jsm

// vim: set ts=2 sw=2 sts=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/.

this.EXPORTED_SYMBOLS = ["Finder", "GetClipboardSearchString"];

const { interfaces: Ci, classes: Cc, utils: Cu } = Components;

Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Geometry.jsm");
Cu.import("resource://gre/modules/Services.jsm");

XPCOMUtils.defineLazyModuleGetter(this, "BrowserUtils",
  "resource://gre/modules/BrowserUtils.jsm");

XPCOMUtils.defineLazyServiceGetter(this, "TextToSubURIService",
                                         "@mozilla.org/intl/texttosuburi;1",
                                         "nsITextToSubURI");
XPCOMUtils.defineLazyServiceGetter(this, "Clipboard",
                                         "@mozilla.org/widget/clipboard;1",
                                         "nsIClipboard");
XPCOMUtils.defineLazyServiceGetter(this, "ClipboardHelper",
                                         "@mozilla.org/widget/clipboardhelper;1",
                                         "nsIClipboardHelper");

const kSelectionMaxLen = 150;
const kMatchesCountLimitPref = "accessibility.typeaheadfind.matchesCountLimit";

function Finder(docShell) {
  this._fastFind = Cc["@mozilla.org/typeaheadfind;1"].createInstance(Ci.nsITypeAheadFind);
  this._fastFind.init(docShell);

  this._currentFoundRange = null;
  this._docShell = docShell;
  this._listeners = [];
  this._previousLink = null;
  this._searchString = null;
  this._highlighter = null;

  docShell.QueryInterface(Ci.nsIInterfaceRequestor)
          .getInterface(Ci.nsIWebProgress)
          .addProgressListener(this, Ci.nsIWebProgress.NOTIFY_LOCATION);
  BrowserUtils.getRootWindow(this._docShell).addEventListener("unload",
    this.onLocationChange.bind(this, { isTopLevel: true }));
}

Finder.prototype = {
  get iterator() {
    if (this._iterator)
      return this._iterator;
    this._iterator = Cu.import("resource://gre/modules/FinderIterator.jsm", null).FinderIterator;
    return this._iterator;
  },

  destroy() {
    if (this._iterator)
      this._iterator.reset();
    let window = this._getWindow();
    if (this._highlighter && window) {
      // if we clear all the references before we hide the highlights (in both
      // highlighting modes), we simply can't use them to find the ranges we
      // need to clear from the selection.
      this._highlighter.hide(window);
      this._highlighter.clear(window);
    }
    this.listeners = [];
    this._docShell.QueryInterface(Ci.nsIInterfaceRequestor)
      .getInterface(Ci.nsIWebProgress)
      .removeProgressListener(this, Ci.nsIWebProgress.NOTIFY_LOCATION);
    this._listeners = [];
    this._currentFoundRange = this._fastFind = this._docShell = this._previousLink =
      this._highlighter = null;
  },

  addResultListener(aListener) {
    if (this._listeners.indexOf(aListener) === -1)
      this._listeners.push(aListener);
  },

  removeResultListener(aListener) {
    this._listeners = this._listeners.filter(l => l != aListener);
  },

  _notify(options) {
    if (typeof options.storeResult != "boolean")
      options.storeResult = true;

    if (options.storeResult) {
      this._searchString = options.searchString;
      this.clipboardSearchString = options.searchString
    }

    let foundLink = this._fastFind.foundLink;
    let linkURL = null;
    if (foundLink) {
      let docCharset = null;
      let ownerDoc = foundLink.ownerDocument;
      if (ownerDoc)
        docCharset = ownerDoc.characterSet;

      linkURL = TextToSubURIService.unEscapeURIForUI(docCharset, foundLink.href);
    }

    options.linkURL = linkURL;
    options.rect = this._getResultRect();
    options.searchString = this._searchString;

    if (!this.iterator.continueRunning({
      caseSensitive: this._fastFind.caseSensitive,
      entireWord: this._fastFind.entireWord,
      linksOnly: options.linksOnly,
      word: options.searchString
    })) {
      this.iterator.stop();
    }

    this.highlighter.update(options);
    this.requestMatchesCount(options.searchString, options.linksOnly);

    this._outlineLink(options.drawOutline);

    for (let l of this._listeners) {
      try {
        l.onFindResult(options);
      } catch (ex) {}
    }
  },

  get searchString() {
    if (!this._searchString && this._fastFind.searchString)
      this._searchString = this._fastFind.searchString;
    return this._searchString;
  },

  get clipboardSearchString() {
    return GetClipboardSearchString(this._getWindow()
                                        .QueryInterface(Ci.nsIInterfaceRequestor)
                                        .getInterface(Ci.nsIWebNavigation)
                                        .QueryInterface(Ci.nsILoadContext));
  },

  set clipboardSearchString(aSearchString) {
    if (!aSearchString || !Clipboard.supportsFindClipboard())
      return;

    ClipboardHelper.copyStringToClipboard(aSearchString,
                                          Ci.nsIClipboard.kFindClipboard);
  },

  set caseSensitive(aSensitive) {
    if (this._fastFind.caseSensitive === aSensitive)
      return;
    this._fastFind.caseSensitive = aSensitive;
    this.iterator.reset();
  },

  set entireWord(aEntireWord) {
    if (this._fastFind.entireWord === aEntireWord)
      return;
    this._fastFind.entireWord = aEntireWord;
    this.iterator.reset();
  },

  get highlighter() {
    if (this._highlighter)
      return this._highlighter;

    const {FinderHighlighter} = Cu.import("resource://gre/modules/FinderHighlighter.jsm", {});
    return this._highlighter = new FinderHighlighter(this);
  },

  get matchesCountLimit() {
    if (typeof this._matchesCountLimit == "number")
      return this._matchesCountLimit;

    this._matchesCountLimit = Services.prefs.getIntPref(kMatchesCountLimitPref) || 0;
    return this._matchesCountLimit;
  },

  _lastFindResult: null,

  /**
   * Used for normal search operations, highlights the first match.
   *
   * @param aSearchString String to search for.
   * @param aLinksOnly Only consider nodes that are links for the search.
   * @param aDrawOutline Puts an outline around matched links.
   */
  fastFind(aSearchString, aLinksOnly, aDrawOutline) {
    this._lastFindResult = this._fastFind.find(aSearchString, aLinksOnly);
    let searchString = this._fastFind.searchString;
    this._notify({
      searchString,
      result: this._lastFindResult,
      findBackwards: false,
      findAgain: false,
      drawOutline: aDrawOutline,
      linksOnly: aLinksOnly
    });
  },

  /**
   * Repeat the previous search. Should only be called after a previous
   * call to Finder.fastFind.
   *
   * @param aFindBackwards Controls the search direction:
   *    true: before current match, false: after current match.
   * @param aLinksOnly Only consider nodes that are links for the search.
   * @param aDrawOutline Puts an outline around matched links.
   */
  findAgain(aFindBackwards, aLinksOnly, aDrawOutline) {
    this._lastFindResult = this._fastFind.findAgain(aFindBackwards, aLinksOnly);
    let searchString = this._fastFind.searchString;
    this._notify({
      searchString,
      result: this._lastFindResult,
      findBackwards: aFindBackwards,
      findAgain: true,
      drawOutline: aDrawOutline,
      linksOnly: aLinksOnly
    });
  },

  /**
   * Forcibly set the search string of the find clipboard to the currently
   * selected text in the window, on supported platforms (i.e. OSX).
   */
  setSearchStringToSelection() {
    let searchString = this.getActiveSelectionText();

    // Empty strings are rather useless to search for.
    if (!searchString.length)
      return null;

    this.clipboardSearchString = searchString;
    return searchString;
  },

  async highlight(aHighlight, aWord, aLinksOnly) {
    await this.highlighter.highlight(aHighlight, aWord, aLinksOnly);
  },

  getInitialSelection() {
    this._getWindow().setTimeout(() => {
      let initialSelection = this.getActiveSelectionText();
      for (let l of this._listeners) {
        try {
          l.onCurrentSelection(initialSelection, true);
        } catch (ex) {}
      }
    }, 0);
  },

  getActiveSelectionText() {
    let focusedWindow = {};
    let focusedElement =
      Services.focus.getFocusedElementForWindow(this._getWindow(), true,
                                                focusedWindow);
    focusedWindow = focusedWindow.value;

    let selText;

    if (focusedElement instanceof Ci.nsIDOMNSEditableElement &&
        focusedElement.editor) {
      // The user may have a selection in an input or textarea.
      selText = focusedElement.editor.selectionController
        .getSelection(Ci.nsISelectionController.SELECTION_NORMAL)
        .toString();
    } else {
      // Look for any selected text on the actual page.
      selText = focusedWindow.getSelection().toString();
    }

    if (!selText)
      return "";

    // Process our text to get rid of unwanted characters.
    selText = selText.trim().replace(/\s+/g, " ");
    let truncLength = kSelectionMaxLen;
    if (selText.length > truncLength) {
      let truncChar = selText.charAt(truncLength).charCodeAt(0);
      if (truncChar >= 0xDC00 && truncChar <= 0xDFFF)
        truncLength++;
      selText = selText.substr(0, truncLength);
    }

    return selText;
  },

  enableSelection() {
    this._fastFind.setSelectionModeAndRepaint(Ci.nsISelectionController.SELECTION_ON);
    this._restoreOriginalOutline();
  },

  removeSelection() {
    this._fastFind.collapseSelection();
    this.enableSelection();
    this.highlighter.clear(this._getWindow());
  },

  focusContent() {
    // Allow Finder listeners to cancel focusing the content.
    for (let l of this._listeners) {
      try {
        if ("shouldFocusContent" in l &&
            !l.shouldFocusContent())
          return;
      } catch (ex) {
        Cu.reportError(ex);
      }
    }

    let fastFind = this._fastFind;
    const fm = Cc["@mozilla.org/focus-manager;1"].getService(Ci.nsIFocusManager);
    try {
      // Try to find the best possible match that should receive focus and
      // block scrolling on focus since find already scrolls. Further
      // scrolling is due to user action, so don't override this.
      if (fastFind.foundLink) {
        fm.setFocus(fastFind.foundLink, fm.FLAG_NOSCROLL);
      } else if (fastFind.foundEditable) {
        fm.setFocus(fastFind.foundEditable, fm.FLAG_NOSCROLL);
        fastFind.collapseSelection();
      } else {
        this._getWindow().focus()
      }
    } catch (e) {}
  },

  onFindbarClose() {
    this.enableSelection();
    this.highlighter.highlight(false);
    this.iterator.reset();
    BrowserUtils.trackToolbarVisibility(this._docShell, "findbar", false);
  },

  onFindbarOpen() {
    BrowserUtils.trackToolbarVisibility(this._docShell, "findbar", true);
  },

  onModalHighlightChange(useModalHighlight) {
    if (this._highlighter)
      this._highlighter.onModalHighlightChange(useModalHighlight);
  },

  onHighlightAllChange(highlightAll) {
    if (this._highlighter)
      this._highlighter.onHighlightAllChange(highlightAll);
    if (this._iterator)
      this._iterator.reset();
  },

  keyPress(aEvent) {
    let controller = this._getSelectionController(this._getWindow());

    switch (aEvent.keyCode) {
      case Ci.nsIDOMKeyEvent.DOM_VK_RETURN:
        if (this._fastFind.foundLink) {
          let view = this._fastFind.foundLink.ownerGlobal;
          this._fastFind.foundLink.dispatchEvent(new view.MouseEvent("click", {
            view,
            cancelable: true,
            bubbles: true,
            ctrlKey: aEvent.ctrlKey,
            altKey: aEvent.altKey,
            shiftKey: aEvent.shiftKey,
            metaKey: aEvent.metaKey
          }));
        }
        break;
      case Ci.nsIDOMKeyEvent.DOM_VK_TAB:
        let direction = Services.focus.MOVEFOCUS_FORWARD;
        if (aEvent.shiftKey) {
          direction = Services.focus.MOVEFOCUS_BACKWARD;
        }
        Services.focus.moveFocus(this._getWindow(), null, direction, 0);
        break;
      case Ci.nsIDOMKeyEvent.DOM_VK_PAGE_UP:
        controller.scrollPage(false);
        break;
      case Ci.nsIDOMKeyEvent.DOM_VK_PAGE_DOWN:
        controller.scrollPage(true);
        break;
      case Ci.nsIDOMKeyEvent.DOM_VK_UP:
        controller.scrollLine(false);
        break;
      case Ci.nsIDOMKeyEvent.DOM_VK_DOWN:
        controller.scrollLine(true);
        break;
    }
  },

  _notifyMatchesCount(result = this._currentMatchesCountResult) {
    // The `_currentFound` property is only used for internal bookkeeping.
    delete result._currentFound;
    result.limit = this.matchesCountLimit;
    if (result.total == result.limit)
      result.total = -1;

    for (let l of this._listeners) {
      try {
        l.onMatchesCountResult(result);
      } catch (ex) {}
    }

    this._currentMatchesCountResult = null;
  },

  requestMatchesCount(aWord, aLinksOnly) {
    if (this._lastFindResult == Ci.nsITypeAheadFind.FIND_NOTFOUND ||
        this.searchString == "" || !aWord || !this.matchesCountLimit) {
      this._notifyMatchesCount({
        total: 0,
        current: 0
      });
      return;
    }

    this._currentFoundRange = this._fastFind.getFoundRange();

    let params = {
      caseSensitive: this._fastFind.caseSensitive,
      entireWord: this._fastFind.entireWord,
      linksOnly: aLinksOnly,
      word: aWord
    };
    if (!this.iterator.continueRunning(params))
      this.iterator.stop();

    this.iterator.start(Object.assign(params, {
      finder: this,
      limit: this.matchesCountLimit,
      listener: this,
      useCache: true,
    })).then(() => {
      // Without a valid result, there's nothing to notify about. This happens
      // when the iterator was started before and won the race.
      if (!this._currentMatchesCountResult || !this._currentMatchesCountResult.total)
        return;
      this._notifyMatchesCount();
    });
  },

  // FinderIterator listener implementation

  onIteratorRangeFound(range) {
    let result = this._currentMatchesCountResult;
    if (!result)
      return;

    ++result.total;
    if (!result._currentFound) {
      ++result.current;
      result._currentFound = (this._currentFoundRange &&
        range.startContainer == this._currentFoundRange.startContainer &&
        range.startOffset == this._currentFoundRange.startOffset &&
        range.endContainer == this._currentFoundRange.endContainer &&
        range.endOffset == this._currentFoundRange.endOffset);
    }
  },

  onIteratorReset() {},

  onIteratorRestart({ word, linksOnly }) {
    this.requestMatchesCount(word, linksOnly);
  },

  onIteratorStart() {
    this._currentMatchesCountResult = {
      total: 0,
      current: 0,
      _currentFound: false
    };
  },

  _getWindow() {
    if (!this._docShell)
      return null;
    return this._docShell.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindow);
  },

  /**
   * Get the bounding selection rect in CSS px relative to the origin of the
   * top-level content document.
   */
  _getResultRect() {
    let topWin = this._getWindow();
    let win = this._fastFind.currentWindow;
    if (!win)
      return null;

    let selection = win.getSelection();
    if (!selection.rangeCount || selection.isCollapsed) {
      // The selection can be into an input or a textarea element.
      let nodes = win.document.querySelectorAll("input, textarea");
      for (let node of nodes) {
        if (node instanceof Ci.nsIDOMNSEditableElement && node.editor) {
          try {
            let sc = node.editor.selectionController;
            selection = sc.getSelection(Ci.nsISelectionController.SELECTION_NORMAL);
            if (selection.rangeCount && !selection.isCollapsed) {
              break;
            }
          } catch (e) {
            // If this textarea is hidden, then its selection controller might
            // not be intialized. Ignore the failure.
          }
        }
      }
    }

    if (!selection.rangeCount || selection.isCollapsed) {
      return null;
    }

    let utils = topWin.QueryInterface(Ci.nsIInterfaceRequestor)
                      .getInterface(Ci.nsIDOMWindowUtils);

    let scrollX = {}, scrollY = {};
    utils.getScrollXY(false, scrollX, scrollY);

    for (let frame = win; frame != topWin; frame = frame.parent) {
      let rect = frame.frameElement.getBoundingClientRect();
      let left = frame.getComputedStyle(frame.frameElement).borderLeftWidth;
      let top = frame.getComputedStyle(frame.frameElement).borderTopWidth;
      scrollX.value += rect.left + parseInt(left, 10);
      scrollY.value += rect.top + parseInt(top, 10);
    }
    let rect = Rect.fromRect(selection.getRangeAt(0).getBoundingClientRect());
    return rect.translate(scrollX.value, scrollY.value);
  },

  _outlineLink(aDrawOutline) {
    let foundLink = this._fastFind.foundLink;

    // Optimization: We are drawing outlines and we matched
    // the same link before, so don't duplicate work.
    if (foundLink == this._previousLink && aDrawOutline)
      return;

    this._restoreOriginalOutline();

    if (foundLink && aDrawOutline) {
      // Backup original outline
      this._tmpOutline = foundLink.style.outline;
      this._tmpOutlineOffset = foundLink.style.outlineOffset;

      // Draw pseudo focus rect
      // XXX Should we change the following style for FAYT pseudo focus?
      // XXX Shouldn't we change default design if outline is visible
      //     already?
      // Don't set the outline-color, we should always use initial value.
      foundLink.style.outline = "1px dotted";
      foundLink.style.outlineOffset = "0";

      this._previousLink = foundLink;
    }
  },

  _restoreOriginalOutline() {
    // Removes the outline around the last found link.
    if (this._previousLink) {
      this._previousLink.style.outline = this._tmpOutline;
      this._previousLink.style.outlineOffset = this._tmpOutlineOffset;
      this._previousLink = null;
    }
  },

  _getSelectionController(aWindow) {
    // display: none iframes don't have a selection controller, see bug 493658
    try {
      if (!aWindow.innerWidth || !aWindow.innerHeight)
        return null;
    } catch (e) {
      // If getting innerWidth or innerHeight throws, we can't get a selection
      // controller.
      return null;
    }

    // Yuck. See bug 138068.
    let docShell = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
                          .getInterface(Ci.nsIWebNavigation)
                          .QueryInterface(Ci.nsIDocShell);

    let controller = docShell.QueryInterface(Ci.nsIInterfaceRequestor)
                             .getInterface(Ci.nsISelectionDisplay)
                             .QueryInterface(Ci.nsISelectionController);
    return controller;
  },

  // Start of nsIWebProgressListener implementation.

  onLocationChange(aWebProgress, aRequest, aLocation, aFlags) {
    if (!aWebProgress.isTopLevel)
      return;
    // Ignore events that don't change the document.
    if (aFlags & Ci.nsIWebProgressListener.LOCATION_CHANGE_SAME_DOCUMENT)
      return;

    // Avoid leaking if we change the page.
    this._lastFindResult = this._previousLink = this._currentFoundRange = null;
    this.highlighter.onLocationChange();
    this.iterator.reset();
  },

  QueryInterface: XPCOMUtils.generateQI([Ci.nsIWebProgressListener,
                                         Ci.nsISupportsWeakReference])
};

function GetClipboardSearchString(aLoadContext) {
  let searchString = "";
  if (!Clipboard.supportsFindClipboard())
    return searchString;

  try {
    let trans = Cc["@mozilla.org/widget/transferable;1"]
                  .createInstance(Ci.nsITransferable);
    trans.init(aLoadContext);
    trans.addDataFlavor("text/unicode");

    Clipboard.getData(trans, Ci.nsIClipboard.kFindClipboard);

    let data = {};
    let dataLen = {};
    trans.getTransferData("text/unicode", data, dataLen);
    if (data.value) {
      data = data.value.QueryInterface(Ci.nsISupportsString);
      searchString = data.toString();
    }
  } catch (ex) {}

  return searchString;
}

this.Finder = Finder;
this.GetClipboardSearchString = GetClipboardSearchString;