summaryrefslogtreecommitdiffstats
path: root/base/content/browser-fullZoom.js
blob: 890cd84403e7c92b20a919549bf6b6bcb5e3836b (plain)
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
/* 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/. */

/**
 * Controls the "full zoom" setting and its site-specific preferences.
 */
var FullZoom = {
  // Identifies the setting in the content prefs database.
  name: "browser.content.full-zoom",

  // browser.zoom.siteSpecific preference cache
  _siteSpecificPref: undefined,

  // browser.zoom.updateBackgroundTabs preference cache
  updateBackgroundTabs: undefined,

  // This maps the browser to monotonically increasing integer
  // tokens. _browserTokenMap[browser] is increased each time the zoom is
  // changed in the browser. See _getBrowserToken and _ignorePendingZoomAccesses.
  _browserTokenMap: new WeakMap(),

  // Stores initial locations if we receive onLocationChange
  // events before we're initialized.
  _initialLocations: new WeakMap(),

  get siteSpecific() {
    return this._siteSpecificPref;
  },

  // nsISupports

  QueryInterface: XPCOMUtils.generateQI([Ci.nsIDOMEventListener,
                                         Ci.nsIObserver,
                                         Ci.nsIContentPrefObserver,
                                         Ci.nsISupportsWeakReference,
                                         Ci.nsISupports]),

  // Initialization & Destruction

  init: function FullZoom_init() {
    gBrowser.addEventListener("ZoomChangeUsingMouseWheel", this);

    // Register ourselves with the service so we know when our pref changes.
    this._cps2 = Cc["@mozilla.org/content-pref/service;1"].
                 getService(Ci.nsIContentPrefService2);
    this._cps2.addObserverForName(this.name, this);

    this._siteSpecificPref =
      gPrefService.getBoolPref("browser.zoom.siteSpecific");
    this.updateBackgroundTabs =
      gPrefService.getBoolPref("browser.zoom.updateBackgroundTabs");
    // Listen for changes to the browser.zoom branch so we can enable/disable
    // updating background tabs and per-site saving and restoring of zoom levels.
    gPrefService.addObserver("browser.zoom.", this, true);

    // If we received onLocationChange events for any of the current browsers
    // before we were initialized we want to replay those upon initialization.
    for (let browser of gBrowser.browsers) {
      if (this._initialLocations.has(browser)) {
        this.onLocationChange(...this._initialLocations.get(browser), browser);
      }
    }

    // This should be nulled after initialization.
    this._initialLocations = null;
  },

  destroy: function FullZoom_destroy() {
    gPrefService.removeObserver("browser.zoom.", this);
    this._cps2.removeObserverForName(this.name, this);
    gBrowser.removeEventListener("ZoomChangeUsingMouseWheel", this);
  },


  // Event Handlers

  // nsIDOMEventListener

  handleEvent: function FullZoom_handleEvent(event) {
    switch (event.type) {
      case "ZoomChangeUsingMouseWheel":
        let browser = this._getTargetedBrowser(event);
        this._ignorePendingZoomAccesses(browser);
        this._applyZoomToPref(browser);
        break;
    }
  },

  // nsIObserver

  observe: function (aSubject, aTopic, aData) {
    switch (aTopic) {
      case "nsPref:changed":
        switch (aData) {
          case "browser.zoom.siteSpecific":
            this._siteSpecificPref =
              gPrefService.getBoolPref("browser.zoom.siteSpecific");
            break;
          case "browser.zoom.updateBackgroundTabs":
            this.updateBackgroundTabs =
              gPrefService.getBoolPref("browser.zoom.updateBackgroundTabs");
            break;
        }
        break;
    }
  },

  // nsIContentPrefObserver

  onContentPrefSet: function FullZoom_onContentPrefSet(aGroup, aName, aValue, aIsPrivate) {
    this._onContentPrefChanged(aGroup, aValue, aIsPrivate);
  },

  onContentPrefRemoved: function FullZoom_onContentPrefRemoved(aGroup, aName, aIsPrivate) {
    this._onContentPrefChanged(aGroup, undefined, aIsPrivate);
  },

  /**
   * Appropriately updates the zoom level after a content preference has
   * changed.
   *
   * @param aGroup  The group of the changed preference.
   * @param aValue  The new value of the changed preference.  Pass undefined to
   *                indicate the preference's removal.
   */
  _onContentPrefChanged: function FullZoom__onContentPrefChanged(aGroup, aValue, aIsPrivate) {
    if (this._isNextContentPrefChangeInternal) {
      // Ignore changes that FullZoom itself makes.  This works because the
      // content pref service calls callbacks before notifying observers, and it
      // does both in the same turn of the event loop.
      delete this._isNextContentPrefChangeInternal;
      return;
    }

    let browser = gBrowser.selectedBrowser;
    if (!browser.currentURI)
      return;

    let ctxt = this._loadContextFromBrowser(browser);
    let domain = this._cps2.extractDomain(browser.currentURI.spec);
    if (aGroup) {
      if (aGroup == domain && ctxt.usePrivateBrowsing == aIsPrivate)
        this._applyPrefToZoom(aValue, browser);
      return;
    }

    this._globalValue = aValue === undefined ? aValue :
                          this._ensureValid(aValue);

    // If the current page doesn't have a site-specific preference, then its
    // zoom should be set to the new global preference now that the global
    // preference has changed.
    let hasPref = false;
    let token = this._getBrowserToken(browser);
    this._cps2.getByDomainAndName(browser.currentURI.spec, this.name, ctxt, {
      handleResult: function () { hasPref = true; },
      handleCompletion: function () {
        if (!hasPref && token.isCurrent)
          this._applyPrefToZoom(undefined, browser);
      }.bind(this)
    });
  },

  // location change observer

  /**
   * Called when the location of a tab changes.
   * When that happens, we need to update the current zoom level if appropriate.
   *
   * @param aURI
   *        A URI object representing the new location.
   * @param aIsTabSwitch
   *        Whether this location change has happened because of a tab switch.
   * @param aBrowser
   *        (optional) browser object displaying the document
   */
  onLocationChange: function FullZoom_onLocationChange(aURI, aIsTabSwitch, aBrowser) {
    let browser = aBrowser || gBrowser.selectedBrowser;

    // If we haven't been initialized yet but receive an onLocationChange
    // notification then let's store and replay it upon initialization.
    if (this._initialLocations) {
      this._initialLocations.set(browser, [aURI, aIsTabSwitch]);
      return;
    }

    // Ignore all pending async zoom accesses in the browser.  Pending accesses
    // that started before the location change will be prevented from applying
    // to the new location.
    this._ignorePendingZoomAccesses(browser);

    if (!aURI || (aIsTabSwitch && !this.siteSpecific)) {
      this._notifyOnLocationChange(browser);
      return;
    }

    // Avoid the cps roundtrip and apply the default/global pref.
    if (aURI.spec == "about:blank") {
      this._applyPrefToZoom(undefined, browser,
                            this._notifyOnLocationChange.bind(this, browser));
      return;
    }

    // Media documents should always start at 1, and are not affected by prefs.
    if (!aIsTabSwitch && browser.isSyntheticDocument) {
      ZoomManager.setZoomForBrowser(browser, 1);
      // _ignorePendingZoomAccesses already called above, so no need here.
      this._notifyOnLocationChange(browser);
      return;
    }

    // See if the zoom pref is cached.
    let ctxt = this._loadContextFromBrowser(browser);
    let pref = this._cps2.getCachedByDomainAndName(aURI.spec, this.name, ctxt);
    if (pref) {
      this._applyPrefToZoom(pref.value, browser,
                            this._notifyOnLocationChange.bind(this, browser));
      return;
    }

    // It's not cached, so we have to asynchronously fetch it.
    let value = undefined;
    let token = this._getBrowserToken(browser);
    this._cps2.getByDomainAndName(aURI.spec, this.name, ctxt, {
      handleResult: function (resultPref) { value = resultPref.value; },
      handleCompletion: function () {
        if (!token.isCurrent) {
          this._notifyOnLocationChange(browser);
          return;
        }
        this._applyPrefToZoom(value, browser,
                              this._notifyOnLocationChange.bind(this, browser));
      }.bind(this)
    });
  },

  // update state of zoom type menu item

  updateMenu: function FullZoom_updateMenu() {
    var menuItem = document.getElementById("toggle_zoom");

    menuItem.setAttribute("checked", !ZoomManager.useFullZoom);
  },

  // Setting & Pref Manipulation

  /**
   * Reduces the zoom level of the page in the current browser.
   */
  reduce: function FullZoom_reduce() {
    ZoomManager.reduce();
    let browser = gBrowser.selectedBrowser;
    this._ignorePendingZoomAccesses(browser);
    this._applyZoomToPref(browser);
  },

  /**
   * Enlarges the zoom level of the page in the current browser.
   */
  enlarge: function FullZoom_enlarge() {
    ZoomManager.enlarge();
    let browser = gBrowser.selectedBrowser;
    this._ignorePendingZoomAccesses(browser);
    this._applyZoomToPref(browser);
  },

  /**
   * Sets the zoom level for the given browser to the given floating
   * point value, where 1 is the default zoom level.
   */
  setZoom: function (value, browser = gBrowser.selectedBrowser) {
    ZoomManager.setZoomForBrowser(browser, value);
    this._ignorePendingZoomAccesses(browser);
    this._applyZoomToPref(browser);
  },

  /**
   * Sets the zoom level of the page in the given browser to the global zoom
   * level.
   *
   * @return A promise which resolves when the zoom reset has been applied.
   */
  reset: function FullZoom_reset(browser = gBrowser.selectedBrowser) {
    let token = this._getBrowserToken(browser);
    let result = this._getGlobalValue(browser).then(value => {
      if (token.isCurrent) {
        ZoomManager.setZoomForBrowser(browser, value === undefined ? 1 : value);
        this._ignorePendingZoomAccesses(browser);
        Services.obs.notifyObservers(browser, "browser-fullZoom:zoomReset", "");
      }
    });
    this._removePref(browser);
    return result;
  },

  /**
   * Set the zoom level for a given browser.
   *
   * Per nsPresContext::setFullZoom, we can set the zoom to its current value
   * without significant impact on performance, as the setting is only applied
   * if it differs from the current setting.  In fact getting the zoom and then
   * checking ourselves if it differs costs more.
   *
   * And perhaps we should always set the zoom even if it was more expensive,
   * since nsDocumentViewer::SetTextZoom claims that child documents can have
   * a different text zoom (although it would be unusual), and it implies that
   * those child text zooms should get updated when the parent zoom gets set,
   * and perhaps the same is true for full zoom
   * (although nsDocumentViewer::SetFullZoom doesn't mention it).
   *
   * So when we apply new zoom values to the browser, we simply set the zoom.
   * We don't check first to see if the new value is the same as the current
   * one.
   *
   * @param aValue     The zoom level value.
   * @param aBrowser   The zoom is set in this browser.  Required.
   * @param aCallback  If given, it's asynchronously called when complete.
   */
  _applyPrefToZoom: function FullZoom__applyPrefToZoom(aValue, aBrowser, aCallback) {
    if (!this.siteSpecific || gInPrintPreviewMode) {
      this._executeSoon(aCallback);
      return;
    }

    // The browser is sometimes half-destroyed because this method is called
    // by content pref service callbacks, which themselves can be called at any
    // time, even after browsers are closed.
    if (!aBrowser.parentNode || aBrowser.isSyntheticDocument) {
      this._executeSoon(aCallback);
      return;
    }

    if (aValue !== undefined) {
      ZoomManager.setZoomForBrowser(aBrowser, this._ensureValid(aValue));
      this._ignorePendingZoomAccesses(aBrowser);
      this._executeSoon(aCallback);
      return;
    }

    let token = this._getBrowserToken(aBrowser);
    this._getGlobalValue(aBrowser).then(value => {
      if (token.isCurrent) {
        ZoomManager.setZoomForBrowser(aBrowser, value === undefined ? 1 : value);
        this._ignorePendingZoomAccesses(aBrowser);
      }
      this._executeSoon(aCallback);
    });
  },

  /**
   * Saves the zoom level of the page in the given browser to the content
   * prefs store.
   *
   * @param browser  The zoom of this browser will be saved.  Required.
   */
  _applyZoomToPref: function FullZoom__applyZoomToPref(browser) {
    Services.obs.notifyObservers(browser, "browser-fullZoom:zoomChange", "");
    if (!this.siteSpecific ||
        gInPrintPreviewMode ||
        browser.isSyntheticDocument)
      return;

    this._cps2.set(browser.currentURI.spec, this.name,
                   ZoomManager.getZoomForBrowser(browser),
                   this._loadContextFromBrowser(browser), {
      handleCompletion: function () {
        this._isNextContentPrefChangeInternal = true;
      }.bind(this),
    });
  },

  /**
   * Removes from the content prefs store the zoom level of the given browser.
   *
   * @param browser  The zoom of this browser will be removed.  Required.
   */
  _removePref: function FullZoom__removePref(browser) {
    Services.obs.notifyObservers(browser, "browser-fullZoom:zoomReset", "");
    if (browser.isSyntheticDocument)
      return;
    let ctxt = this._loadContextFromBrowser(browser);
    this._cps2.removeByDomainAndName(browser.currentURI.spec, this.name, ctxt, {
      handleCompletion: function () {
        this._isNextContentPrefChangeInternal = true;
      }.bind(this),
    });
  },

  // Utilities

  /**
   * Returns the zoom change token of the given browser.  Asynchronous
   * operations that access the given browser's zoom should use this method to
   * capture the token before starting and use token.isCurrent to determine if
   * it's safe to access the zoom when done.  If token.isCurrent is false, then
   * after the async operation started, either the browser's zoom was changed or
   * the browser was destroyed, and depending on what the operation is doing, it
   * may no longer be safe to set and get its zoom.
   *
   * @param browser  The token of this browser will be returned.
   * @return  An object with an "isCurrent" getter.
   */
  _getBrowserToken: function FullZoom__getBrowserToken(browser) {
    let map = this._browserTokenMap;
    if (!map.has(browser))
      map.set(browser, 0);
    return {
      token: map.get(browser),
      get isCurrent() {
        // At this point, the browser may have been destructed and unbound but
        // its outer ID not removed from the map because outer-window-destroyed
        // hasn't been received yet.  In that case, the browser is unusable, it
        // has no properties, so return false.  Check for this case by getting a
        // property, say, docShell.
        return map.get(browser) === this.token && browser.parentNode;
      },
    };
  },

  /**
   * Returns the browser that the supplied zoom event is associated with.
   * @param event  The ZoomChangeUsingMouseWheel event.
   * @return  The associated browser element, if one exists, otherwise null.
   */
  _getTargetedBrowser: function FullZoom__getTargetedBrowser(event) {
    let target = event.originalTarget;

    // With remote content browsers, the event's target is the browser
    // we're looking for.
    const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
    if (target instanceof window.XULElement &&
        target.localName == "browser" &&
        target.namespaceURI == XUL_NS)
      return target;

    // With in-process content browsers, the event's target is the content
    // document.
    if (target.nodeType == Node.DOCUMENT_NODE)
      return gBrowser.getBrowserForDocument(target);

    throw new Error("Unexpected ZoomChangeUsingMouseWheel event source");
  },

  /**
   * Increments the zoom change token for the given browser so that pending
   * async operations know that it may be unsafe to access they zoom when they
   * finish.
   *
   * @param browser  Pending accesses in this browser will be ignored.
   */
  _ignorePendingZoomAccesses: function FullZoom__ignorePendingZoomAccesses(browser) {
    let map = this._browserTokenMap;
    map.set(browser, (map.get(browser) || 0) + 1);
  },

  _ensureValid: function FullZoom__ensureValid(aValue) {
    // Note that undefined is a valid value for aValue that indicates a known-
    // not-to-exist value.
    if (isNaN(aValue))
      return 1;

    if (aValue < ZoomManager.MIN)
      return ZoomManager.MIN;

    if (aValue > ZoomManager.MAX)
      return ZoomManager.MAX;

    return aValue;
  },

  /**
   * Gets the global browser.content.full-zoom content preference.
   *
   * @param browser   The browser pertaining to the zoom.
   * @returns Promise<prefValue>
   *                  Resolves to the preference value when done.
   */
  _getGlobalValue: function FullZoom__getGlobalValue(browser) {
    // * !("_globalValue" in this) => global value not yet cached.
    // * this._globalValue === undefined => global value known not to exist.
    // * Otherwise, this._globalValue is a number, the global value.
    return new Promise(resolve => {
      if ("_globalValue" in this) {
        resolve(this._globalValue);
        return;
      }
      let value = undefined;
      this._cps2.getGlobal(this.name, this._loadContextFromBrowser(browser), {
        handleResult: function (pref) { value = pref.value; },
        handleCompletion: (reason) => {
          this._globalValue = this._ensureValid(value);
          resolve(this._globalValue);
        }
      });
    });
  },

  /**
   * Gets the load context from the given Browser.
   *
   * @param Browser  The Browser whose load context will be returned.
   * @return        The nsILoadContext of the given Browser.
   */
  _loadContextFromBrowser: function FullZoom__loadContextFromBrowser(browser) {
    return browser.loadContext;
  },

  /**
   * Asynchronously broadcasts "browser-fullZoom:location-change" so that
   * listeners can be notified when the zoom levels on those pages change.
   * The notification is always asynchronous so that observers are guaranteed a
   * consistent behavior.
   */
  _notifyOnLocationChange: function FullZoom__notifyOnLocationChange(browser) {
    this._executeSoon(function () {
      Services.obs.notifyObservers(browser, "browser-fullZoom:location-change", "");
    });
  },

  _executeSoon: function FullZoom__executeSoon(callback) {
    if (!callback)
      return;
    Services.tm.mainThread.dispatch(callback, Ci.nsIThread.DISPATCH_NORMAL);
  },
};