michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = [
michael@0:   "onSpellCheck",
michael@0: ];
michael@0: 
michael@0: const SPELL_CHECK_ENDED_TOPIC = "inlineSpellChecker-spellCheck-ended";
michael@0: const SPELL_CHECK_STARTED_TOPIC = "inlineSpellChecker-spellCheck-started";
michael@0: 
michael@0: const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
michael@0: 
michael@0: /**
michael@0:  * Waits until spell checking has stopped on the given element.
michael@0:  *
michael@0:  * When a spell check is pending, this waits indefinitely until the spell check
michael@0:  * ends.  When a spell check is not pending, it waits a small number of turns of
michael@0:  * the event loop: if a spell check begins, it resumes waiting indefinitely for
michael@0:  * the end, and otherwise it stops waiting and calls the callback.
michael@0:  *
michael@0:  * This this can therefore trap spell checks that have not started at the time
michael@0:  * of calling, spell checks that have already started, multiple consecutive
michael@0:  * spell checks, and the absence of spell checks altogether.
michael@0:  *
michael@0:  * @param editableElement  The element being spell checked.
michael@0:  * @param callback         Called when spell check has completed or enough turns
michael@0:  *                         of the event loop have passed to determine it has not
michael@0:  *                         started.
michael@0:  */
michael@0: function onSpellCheck(editableElement, callback) {
michael@0:   let editor = editableElement.editor;
michael@0:   if (!editor) {
michael@0:     let win = editableElement.ownerDocument.defaultView;
michael@0:     editor = win.QueryInterface(Ci.nsIInterfaceRequestor).
michael@0:                  getInterface(Ci.nsIWebNavigation).
michael@0:                  QueryInterface(Ci.nsIInterfaceRequestor).
michael@0:                  getInterface(Ci.nsIEditingSession).
michael@0:                  getEditorForWindow(win);
michael@0:   }
michael@0:   if (!editor)
michael@0:     throw new Error("Unable to find editor for element " + editableElement);
michael@0: 
michael@0:   try {
michael@0:     // False is important here.  Pass false so that the inline spell checker
michael@0:     // isn't created if it doesn't already exist.
michael@0:     var isc = editor.getInlineSpellChecker(false);
michael@0:   }
michael@0:   catch (err) {
michael@0:     // getInlineSpellChecker throws if spell checking is not enabled instead of
michael@0:     // just returning null, which seems kind of lame.  (Spell checking is not
michael@0:     // enabled on Android.)  The point here is only to determine whether spell
michael@0:     // check is pending, and if getInlineSpellChecker throws, then it's not
michael@0:     // pending.
michael@0:   }
michael@0:   let waitingForEnded = isc && isc.spellCheckPending;
michael@0:   let count = 0;
michael@0: 
michael@0:   function observe(subj, topic, data) {
michael@0:     if (subj != editor)
michael@0:       return;
michael@0:     count = 0;
michael@0:     let expectedTopic = waitingForEnded ? SPELL_CHECK_ENDED_TOPIC :
michael@0:                         SPELL_CHECK_STARTED_TOPIC;
michael@0:     if (topic != expectedTopic)
michael@0:       Cu.reportError("Expected " + expectedTopic + " but got " + topic + "!");
michael@0:     waitingForEnded = !waitingForEnded;
michael@0:   }
michael@0: 
michael@0:   let os = Cc["@mozilla.org/observer-service;1"].
michael@0:            getService(Ci.nsIObserverService);
michael@0:   os.addObserver(observe, SPELL_CHECK_STARTED_TOPIC, false);
michael@0:   os.addObserver(observe, SPELL_CHECK_ENDED_TOPIC, false);
michael@0: 
michael@0:   let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
michael@0:   timer.init(function tick() {
michael@0:     // Wait an arbitrarily large number -- 50 -- turns of the event loop before
michael@0:     // declaring that no spell checks will start.
michael@0:     if (waitingForEnded || ++count < 50)
michael@0:       return;
michael@0:     timer.cancel();
michael@0:     os.removeObserver(observe, SPELL_CHECK_STARTED_TOPIC);
michael@0:     os.removeObserver(observe, SPELL_CHECK_ENDED_TOPIC);
michael@0:     callback();
michael@0:   }, 0, Ci.nsITimer.TYPE_REPEATING_SLACK);
michael@0: };