dom/base/nsFocusManager.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef nsFocusManager_h___
   8 #define nsFocusManager_h___
   9
  10 #include "nsCycleCollectionParticipant.h"
  11 #include "nsIContent.h"
  12 #include "mozilla/dom/Document.h"
  13 #include "nsIFocusManager.h"
  14 #include "nsIObserver.h"
  15 #include "nsWeakReference.h"
  16 #include "mozilla/Attributes.h"
  17 #include "mozilla/RefPtr.h"
  18 #include "mozilla/StaticPtr.h"
  19
  20 #define FOCUSMANAGER_CONTRACTID "@mozilla.org/focus-manager;1"
  21
  22 class nsIContent;
  23 class nsPIDOMWindowOuter;
  24
  25 namespace mozilla {
  26 class PresShell;
  27 namespace dom {
  28 class Element;
  29 class HTMLAreaElement;
  30 struct FocusOptions;
  31 class BrowserParent;
  32 class ContentChild;
  33 class ContentParent;
  34 }  // namespace dom
  35 }  // namespace mozilla
  36
  37 struct nsDelayedBlurOrFocusEvent;
  38
  39 /**
  40  * The focus manager keeps track of where the focus is, that is, the node
  41  * which receives key events.
  42  */
  43
  44 class nsFocusManager final : public nsIFocusManager,
  45                              public nsIObserver,
  46                              public nsSupportsWeakReference {
  47   using InputContextAction = mozilla::widget::InputContextAction;
  48   using Document = mozilla::dom::Document;
  49   friend class mozilla::dom::ContentChild;
  50   friend class mozilla::dom::ContentParent;
  51
  52  public:
  53   NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsFocusManager, nsIFocusManager)
  54   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  55   NS_DECL_NSIOBSERVER
  56   NS_DECL_NSIFOCUSMANAGER
  57
  58   // called to initialize and stop the focus manager at startup and shutdown
  59   static nsresult Init();
  60   static void Shutdown();
  61
  62   // Simple helper to call SetFocusedWindow on the instance.
  63   //
  64   // This raises the window and switches to the tab as needed.
  65   MOZ_CAN_RUN_SCRIPT static void FocusWindow(
  66       nsPIDOMWindowOuter* aWindow, mozilla::dom::CallerType aCallerType);
  67
  68   MOZ_CAN_RUN_SCRIPT_BOUNDARY static void PrefChanged(const char* aPref,
  69                                                       void* aSelf);
  70   MOZ_CAN_RUN_SCRIPT void PrefChanged(const char* aPref);
  71
  72   /**
  73    * Retrieve the single focus manager.
  74    */
  75   static nsFocusManager* GetFocusManager() { return sInstance; }
  76
  77   /**
  78    * A faster version of nsIFocusManager::GetFocusedElement, returning a
  79    * raw Element pointer (instead of having AddRef-ed Element
  80    * pointer filled in to an out-parameter).
  81    */
  82   mozilla::dom::Element* GetFocusedElement() { return mFocusedElement; }
  83   static mozilla::dom::Element* GetFocusedElementStatic() {
  84     return sInstance ? sInstance->GetFocusedElement() : nullptr;
  85   }
  86
  87   /**
  88    * Returns true if aContent currently has focus.
  89    */
  90   bool IsFocused(nsIContent* aContent);
  91
  92   /**
  93    * Returns true if test mode is enabled.
  94    */
  95   bool IsTestMode();
  96
  97   /**
  98    * Return a focused window. Version of nsIFocusManager::GetFocusedWindow.
  99    */
 100   nsPIDOMWindowOuter* GetFocusedWindow() const { return mFocusedWindow; }
 101
 102   /**
 103    * In the chrome process, retrieves the BrowsingContext corresponding
 104    * to GetFocusedWindow(). In a content process, retrieves the
 105    * focused BrowsingContext, which may not belong to this process.
 106    */
 107   mozilla::dom::BrowsingContext* GetFocusedBrowsingContext() const {
 108     if (XRE_IsParentProcess()) {
 109       if (mFocusedWindow) {
 110         return mFocusedWindow->GetBrowsingContext();
 111       }
 112       return nullptr;
 113     }
 114     return mFocusedBrowsingContextInContent;
 115   }
 116
 117   /**
 118    * Returns whether the given browsing context is in the active window.
 119    */
 120   bool IsInActiveWindow(mozilla::dom::BrowsingContext*) const;
 121
 122   /**
 123    * Return an active window. Version of nsIFocusManager::GetActiveWindow.
 124    */
 125   nsPIDOMWindowOuter* GetActiveWindow() const { return mActiveWindow; }
 126
 127   /**
 128    * In the chrome process, retrieves the BrowsingContext corresponding
 129    * to GetActiveWindow(). In a content process, retrieves the
 130    * BrowsingContext of the top-level Web content in the active tab if
 131    * in the same process as the caller or nullptr otherwise.
 132    */
 133   mozilla::dom::BrowsingContext* GetActiveBrowsingContext() const {
 134     if (XRE_IsParentProcess()) {
 135       if (mActiveWindow) {
 136         return mActiveWindow->GetBrowsingContext();
 137       }
 138       return nullptr;
 139     }
 140     return mActiveBrowsingContextInContent;
 141   }
 142
 143   /**
 144    * Called when content has been removed.
 145    */
 146   MOZ_CAN_RUN_SCRIPT nsresult ContentRemoved(Document* aDocument,
 147                                              nsIContent* aContent);
 148
 149   void NeedsFlushBeforeEventHandling(mozilla::dom::Element* aElement) {
 150     if (mFocusedElement == aElement) {
 151       mEventHandlingNeedsFlush = true;
 152     }
 153   }
 154
 155   bool CanSkipFocus(nsIContent* aContent);
 156
 157   MOZ_CAN_RUN_SCRIPT void FlushBeforeEventHandlingIfNeeded(
 158       nsIContent* aContent) {
 159     if (mEventHandlingNeedsFlush) {
 160       nsCOMPtr<Document> doc = aContent->GetComposedDoc();
 161       if (doc) {
 162         mEventHandlingNeedsFlush = false;
 163         doc->FlushPendingNotifications(mozilla::FlushType::Layout);
 164       }
 165     }
 166   }
 167
 168   /**
 169    * Update the caret with current mode (whether in caret browsing mode or not).
 170    */
 171   MOZ_CAN_RUN_SCRIPT void UpdateCaretForCaretBrowsingMode();
 172
 173   /** @see nsIFocusManager.getLastFocusMethod() */
 174   uint32_t GetLastFocusMethod(nsPIDOMWindowOuter*) const;
 175
 176   /**
 177    * Returns the content node that would be focused if aWindow was in an
 178    * active window. This will traverse down the frame hierarchy, starting at
 179    * the given window aWindow. Sets aFocusedWindow to the window with the
 180    * document containing aFocusedContent. If no element is focused,
 181    * aFocusedWindow may be still be set -- this means that the document is
 182    * focused but no element within it is focused.
 183    *
 184    * aWindow, aFocusIsOutOfProcess, aFocusedWindow must all be non-null.
 185    */
 186   enum SearchRange {
 187     // Return focused content in aWindow.  So, aFocusedWindow is always aWindow.
 188     eOnlyCurrentWindow,
 189     // Return focused content in aWindow or one of all sub windows.
 190     eIncludeAllDescendants,
 191     // Return focused content in aWindow or one of visible sub windows.
 192     eIncludeVisibleDescendants,
 193   };
 194   static mozilla::dom::Element* GetFocusedDescendant(
 195       nsPIDOMWindowOuter* aWindow, SearchRange aSearchRange,
 196       nsPIDOMWindowOuter** aFocusedWindow);
 197
 198   /**
 199    * Helper function for MoveFocus which determines the next element
 200    * to move the focus to and returns it in aNextContent.
 201    *
 202    * aWindow is the window to adjust the focus within, and aStart is
 203    * the element to start navigation from. For tab key navigation,
 204    * this should be the currently focused element.
 205    *
 206    * aType is the type passed to MoveFocus. If aNoParentTraversal is set,
 207    * navigation is not done to parent documents and iteration returns to the
 208    * beginning (or end) of the starting document.
 209    *
 210    * aNavigateByKey to move focus by keyboard as a side effect of computing the
 211    * next target.
 212    */
 213   MOZ_CAN_RUN_SCRIPT nsresult DetermineElementToMoveFocus(
 214       nsPIDOMWindowOuter* aWindow, nsIContent* aStart, int32_t aType,
 215       bool aNoParentTraversal, bool aNavigateByKey, nsIContent** aNextContent);
 216
 217   /**
 218    * Setter for focusedWindow with CallerType
 219    */
 220   MOZ_CAN_RUN_SCRIPT nsresult SetFocusedWindowWithCallerType(
 221       mozIDOMWindowProxy* aWindowToFocus, mozilla::dom::CallerType aCallerType);
 222
 223   /**
 224    * Given an element, which must be the focused element, activate the remote
 225    * frame it embeds, if any.
 226    */
 227   void ActivateRemoteFrameIfNeeded(mozilla::dom::Element&, uint64_t aActionId);
 228
 229   /**
 230    * Raises the top-level window aWindow at the widget level.
 231    */
 232   MOZ_CAN_RUN_SCRIPT void RaiseWindow(nsPIDOMWindowOuter* aWindow,
 233                                       mozilla::dom::CallerType aCallerType,
 234                                       uint64_t aActionId);
 235
 236   /**
 237    * Called when a window has been raised.
 238    */
 239   MOZ_CAN_RUN_SCRIPT void WindowRaised(mozIDOMWindowProxy* aWindow,
 240                                        uint64_t aActionId);
 241
 242   /**
 243    * Called when a window has been lowered.
 244    */
 245   MOZ_CAN_RUN_SCRIPT void WindowLowered(mozIDOMWindowProxy* aWindow,
 246                                         uint64_t aActionId);
 247
 248   /**
 249    * Called when a new document in a window is shown.
 250    *
 251    * If aNeedsFocus is true, then focus events are expected to be fired on the
 252    * window if this window is in the focused window chain.
 253    */
 254   MOZ_CAN_RUN_SCRIPT void WindowShown(mozIDOMWindowProxy* aWindow,
 255                                       bool aNeedsFocus);
 256
 257   /**
 258    * Called when a document in a window has been hidden or otherwise can no
 259    * longer accept focus.
 260    */
 261   MOZ_CAN_RUN_SCRIPT void WindowHidden(mozIDOMWindowProxy* aWindow,
 262                                        uint64_t aActionId);
 263
 264   /**
 265    * Fire any events that have been delayed due to synchronized actions.
 266    */
 267   MOZ_CAN_RUN_SCRIPT void FireDelayedEvents(Document* aDocument);
 268
 269   void WasNuked(nsPIDOMWindowOuter* aWindow);
 270
 271   static uint32_t ProgrammaticFocusFlags(
 272       const mozilla::dom::FocusOptions& aOptions);
 273
 274   /**
 275    * Returns an InputContextAction cause for aFlags.
 276    */
 277   static InputContextAction::Cause GetFocusMoveActionCause(uint32_t aFlags);
 278
 279   /**
 280    * Notify of re-focus to same element.
 281    *
 282    * aElement is focused element.
 283    */
 284   MOZ_CAN_RUN_SCRIPT void NotifyOfReFocus(mozilla::dom::Element& aElement);
 285
 286   static void MarkUncollectableForCCGeneration(uint32_t aGeneration);
 287
 288   struct BlurredElementInfo {
 289     const mozilla::OwningNonNull<mozilla::dom::Element> mElement;
 290
 291     explicit BlurredElementInfo(mozilla::dom::Element&);
 292     ~BlurredElementInfo();
 293   };
 294
 295  protected:
 296   nsFocusManager();
 297   ~nsFocusManager();
 298
 299   /**
 300    * Ensure that the widget associated with the currently focused window is
 301    * focused at the widget level.
 302    */
 303   void EnsureCurrentWidgetFocused(mozilla::dom::CallerType aCallerType);
 304
 305   /**
 306    * Activate or deactivate the window and send the activate/deactivate events.
 307    */
 308   void ActivateOrDeactivate(nsPIDOMWindowOuter* aWindow, bool aActive);
 309
 310   /**
 311    * Blur whatever is currently focused and focus aNewContent. aFlags is a
 312    * bitmask of the flags defined in nsIFocusManager. If aFocusChanged is
 313    * true, then the focus has actually shifted and the caret position will be
 314    * updated to the new focus, aNewContent will be scrolled into view (unless
 315    * a flag disables this) and the focus method for the window will be updated.
 316    * If aAdjustWidget is false, don't change the widget focus state.
 317    *
 318    * All actual focus changes must use this method to do so. (as opposed
 319    * to those that update the focus in an inactive window for instance).
 320    *
 321    * Returns Nothing() if we end up not trying to focus the element,
 322    * otherwise returns the generated action id.
 323    */
 324   MOZ_CAN_RUN_SCRIPT mozilla::Maybe<uint64_t> SetFocusInner(
 325       mozilla::dom::Element* aNewContent, int32_t aFlags, bool aFocusChanged,
 326       bool aAdjustWidget);
 327
 328   /**
 329    * Returns true if aPossibleAncestor is the same as aWindow or an
 330    * ancestor of aWindow.
 331    */
 332   bool IsSameOrAncestor(nsPIDOMWindowOuter* aPossibleAncestor,
 333                         nsPIDOMWindowOuter* aWindow) const;
 334   bool IsSameOrAncestor(nsPIDOMWindowOuter* aPossibleAncestor,
 335                         mozilla::dom::BrowsingContext* aContext) const;
 336   bool IsSameOrAncestor(mozilla::dom::BrowsingContext* aPossibleAncestor,
 337                         nsPIDOMWindowOuter* aWindow) const;
 338
 339  public:
 340   bool IsSameOrAncestor(mozilla::dom::BrowsingContext* aPossibleAncestor,
 341                         mozilla::dom::BrowsingContext* aContext) const;
 342
 343  protected:
 344   /**
 345    * Returns the window that is the lowest common ancestor of both aWindow
 346    * and aContext, or null if they share no common ancestor.
 347    */
 348   mozilla::dom::BrowsingContext* GetCommonAncestor(
 349       nsPIDOMWindowOuter* aWindow, mozilla::dom::BrowsingContext* aContext);
 350
 351   /**
 352    * When aBrowsingContext is focused or blurred, adjust the ancestors of
 353    * aBrowsingContext so that they also have their corresponding frames focused
 354    * or blurred. Thus, one can start at the active top-level window and navigate
 355    * down the currently focused elements for each frame in the tree to get to
 356    * aBrowsingContext.
 357    */
 358   MOZ_CAN_RUN_SCRIPT bool AdjustInProcessWindowFocus(
 359       mozilla::dom::BrowsingContext* aBrowsingContext, bool aCheckPermission,
 360       bool aIsVisible, uint64_t aActionId, bool aShouldClearAncestorFocus,
 361       mozilla::dom::BrowsingContext* aAncestorBrowsingContextToFocus);
 362
 363   MOZ_CAN_RUN_SCRIPT void AdjustWindowFocus(
 364       mozilla::dom::BrowsingContext* aBrowsingContext, bool aCheckPermission,
 365       bool aIsVisible, uint64_t aActionId, bool aShouldClearAncestorFocus,
 366       mozilla::dom::BrowsingContext* aAncestorBrowsingContextToFocus);
 367
 368   /**
 369    * Returns true if aWindow is visible.
 370    */
 371   bool IsWindowVisible(nsPIDOMWindowOuter* aWindow);
 372
 373   /**
 374    * Returns true if aContent is a root element and not focusable.
 375    * I.e., even if aContent is editable root element, this returns true when
 376    * the document is in designMode.
 377    *
 378    * @param aContent must not be null and must be in a document.
 379    */
 380   bool IsNonFocusableRoot(nsIContent* aContent);
 381
 382   /**
 383    * First flushes the pending notifications to ensure the PresShell and frames
 384    * are updated.
 385    * Checks and returns aElement if it may be focused, another element node if
 386    * the focus should be retargeted at another node, or null if the node
 387    * cannot be focused. aFlags are the flags passed to SetFocus and similar
 388    * methods.
 389    *
 390    * An element is focusable if it is in a document, the document isn't in
 391    * print preview mode and the element has an nsIFrame where the
 392    * IsFocusable method returns true. For <area> elements, there is no
 393    * frame, so only the IsFocusable method on the content node must be
 394    * true.
 395    */
 396   MOZ_CAN_RUN_SCRIPT mozilla::dom::Element* FlushAndCheckIfFocusable(
 397       mozilla::dom::Element* aElement, uint32_t aFlags);
 398
 399   /**
 400    * Blurs the currently focused element. Returns false if another element was
 401    * focused as a result. This would mean that the caller should not proceed
 402    * with a pending call to Focus. Normally, true would be returned.
 403    *
 404    * The currently focused element within aBrowsingContextToClear will be
 405    * cleared. aBrowsingContextToClear may be null, which means that no window is
 406    * cleared. This will be the case, for example, when lowering a window, as we
 407    * want to fire a blur, but not actually change what element would be focused,
 408    * so that the same element will be focused again when the window is raised.
 409    *
 410    * aAncestorBrowsingContextToFocus should be set to the common ancestor of the
 411    * window that is being blurred and the window that is going to focused, when
 412    * switching focus to a sibling window.
 413    *
 414    * aIsLeavingDocument should be set to true if the document/window is being
 415    * blurred as well. Document/window blur events will be fired. It should be
 416    * false if an element is the same document is about to be focused.
 417    *
 418    * If aAdjustWidget is false, don't change the widget focus state.
 419    */
 420   MOZ_CAN_RUN_SCRIPT bool Blur(
 421       mozilla::dom::BrowsingContext* aBrowsingContextToClear,
 422       mozilla::dom::BrowsingContext* aAncestorBrowsingContextToFocus,
 423       bool aIsLeavingDocument, bool aAdjustWidget, bool aRemainActive,
 424       uint64_t aActionId, mozilla::dom::Element* aElementToFocus = nullptr);
 425   MOZ_CAN_RUN_SCRIPT void BlurFromOtherProcess(
 426       mozilla::dom::BrowsingContext* aFocusedBrowsingContext,
 427       mozilla::dom::BrowsingContext* aBrowsingContextToClear,
 428       mozilla::dom::BrowsingContext* aAncestorBrowsingContextToFocus,
 429       bool aIsLeavingDocument, bool aAdjustWidget, uint64_t aActionId);
 430   MOZ_CAN_RUN_SCRIPT bool BlurImpl(
 431       mozilla::dom::BrowsingContext* aBrowsingContextToClear,
 432       mozilla::dom::BrowsingContext* aAncestorBrowsingContextToFocus,
 433       bool aIsLeavingDocument, bool aAdjustWidget, bool aRemainActive,
 434       mozilla::dom::Element* aElementToFocus, uint64_t aActionId);
 435
 436   /**
 437    * Focus an element in the active window and child frame.
 438    *
 439    * aWindow is the window containing the element aContent to focus.
 440    *
 441    * aFlags is the flags passed to the various focus methods in
 442    * nsIFocusManager.
 443    *
 444    * aIsNewDocument should be true if a new document is being focused.
 445    * Document/window focus events will be fired.
 446    *
 447    * aFocusChanged should be true if a new content node is being focused, so
 448    * the focused content will be scrolled into view and the caret position
 449    * will be updated. If false is passed, then a window is simply being
 450    * refocused, for instance, due to a window being raised, or a tab is being
 451    * switched to.
 452    *
 453    * If aFocusChanged is true, then the focus has moved to a new location.
 454    * Otherwise, the focus is just being updated because the window was
 455    * raised.
 456    *
 457    * aWindowRaised should be true if the window is being raised. In this case,
 458    * command updaters will not be called.
 459    *
 460    * If aAdjustWidget is false, don't change the widget focus state.
 461    */
 462   MOZ_CAN_RUN_SCRIPT void Focus(
 463       nsPIDOMWindowOuter* aWindow, mozilla::dom::Element* aContent,
 464       uint32_t aFlags, bool aIsNewDocument, bool aFocusChanged,
 465       bool aWindowRaised, bool aAdjustWidget, uint64_t aActionId,
 466       const mozilla::Maybe<BlurredElementInfo>& = mozilla::Nothing());
 467
 468   /**
 469    * Send a focus or blur event at aTarget. It may be added to the delayed
 470    * event queue if the document is suppressing events.
 471    *
 472    * aEventMessage should be either eFocus or eBlur.
 473    *
 474    * aWindowRaised should only be true if called from WindowRaised.
 475    */
 476   MOZ_CAN_RUN_SCRIPT void SendFocusOrBlurEvent(
 477       mozilla::EventMessage aEventMessage, mozilla::PresShell* aPresShell,
 478       Document* aDocument, mozilla::dom::EventTarget* aTarget,
 479       bool aWindowRaised, bool aIsRefocus = false,
 480       mozilla::dom::EventTarget* aRelatedTarget = nullptr);
 481   /**
 482    * Fire a focus or blur event at aTarget.
 483    *
 484    * aEventMessage should be either eFocus or eBlur.
 485    * For blur events, aFocusMethod should normally be non-zero.
 486    *
 487    * aWindowRaised should only be true if called from WindowRaised.
 488    */
 489   MOZ_CAN_RUN_SCRIPT void FireFocusOrBlurEvent(
 490       mozilla::EventMessage aEventMessage, mozilla::PresShell* aPresShell,
 491       mozilla::dom::EventTarget* aTarget, bool aWindowRaised,
 492       bool aIsRefocus = false,
 493       mozilla::dom::EventTarget* aRelatedTarget = nullptr);
 494
 495   /**
 496    *  Fire a focusin or focusout event
 497    *
 498    *  aEventMessage should be either eFocusIn or eFocusOut.
 499    *
 500    *  aTarget is the content the event will fire on (the object that gained
 501    *  focus for focusin, the object blurred for focusout).
 502    *
 503    *  aCurrentFocusedWindow is the window focused before the focus/blur event
 504    *  was fired.
 505    *
 506    *  aCurrentFocusedContent is the content focused before the focus/blur event
 507    *  was fired.
 508    *
 509    *  aRelatedTarget is the content related to the event (the object
 510    *  losing focus for focusin, the object getting focus for focusout).
 511    */
 512   MOZ_CAN_RUN_SCRIPT void FireFocusInOrOutEvent(
 513       mozilla::EventMessage aEventMessage, mozilla::PresShell* aPresShell,
 514       mozilla::dom::EventTarget* aTarget,
 515       nsPIDOMWindowOuter* aCurrentFocusedWindow,
 516       nsIContent* aCurrentFocusedContent,
 517       mozilla::dom::EventTarget* aRelatedTarget = nullptr);
 518
 519   /**
 520    * Scrolls aContent into view unless the FLAG_NOSCROLL flag is set.
 521    */
 522   MOZ_CAN_RUN_SCRIPT
 523   void ScrollIntoView(mozilla::PresShell* aPresShell, nsIContent* aContent,
 524                       uint32_t aFlags);
 525
 526   /**
 527    * Updates the caret positon and visibility to match the focus.
 528    *
 529    * aMoveCaretToFocus should be true to move the caret to aContent.
 530    *
 531    * aUpdateVisibility should be true to update whether the caret is
 532    * visible or not.
 533    */
 534   MOZ_CAN_RUN_SCRIPT void UpdateCaret(bool aMoveCaretToFocus,
 535                                       bool aUpdateVisibility,
 536                                       nsIContent* aContent);
 537
 538   /**
 539    * Helper method to move the caret to the focused element aContent.
 540    */
 541   MOZ_CAN_RUN_SCRIPT void MoveCaretToFocus(mozilla::PresShell* aPresShell,
 542                                            nsIContent* aContent);
 543
 544   /**
 545    * Makes the caret visible or not, depending on aVisible.
 546    */
 547   nsresult SetCaretVisible(mozilla::PresShell* aPresShell, bool aVisible,
 548                            nsIContent* aContent);
 549
 550   // the remaining functions are used for tab key and document-navigation
 551
 552   /**
 553    * Retrieves the start and end points of the current selection for
 554    * aDocument and stores them in aStartContent and aEndContent.
 555    */
 556   void GetSelectionLocation(Document* aDocument, mozilla::PresShell* aPresShell,
 557                             nsIContent** aStartContent,
 558                             nsIContent** aEndContent);
 559
 560   /**
 561    * Retrieve the next tabbable element in scope owned by aOwner, using
 562    * focusability and tabindex to determine the tab order.
 563    *
 564    * aOwner is the owner of scope to search in.
 565    *
 566    * aStartContent is the starting point for this call of this method.
 567    *
 568    * aOriginalStartContent is the initial starting point for sequential
 569    * navigation.
 570    *
 571    * aForward should be true for forward navigation or false for backward
 572    * navigation.
 573    *
 574    * aCurrentTabIndex is the current tabindex.
 575    *
 576    * aIgnoreTabIndex to ignore the current tabindex and find the element
 577    * irrespective or the tab index.
 578    *
 579    * aForDocumentNavigation informs whether we're navigating only through
 580    * documents.
 581    *
 582    * aSkipOwner to skip owner while searching. The flag is set when caller is
 583    * |GetNextTabbableContent| in order to let caller handle owner.
 584    *
 585    * aReachedToEndForDocumentNavigation is true when this is a document
 586    * navigation and the focus algorithm has reached to the end of the top-level
 587    * document.
 588    *
 589    * NOTE:
 590    *   Consider the method searches downwards in flattened subtree
 591    *   rooted at aOwner.
 592    */
 593   MOZ_CAN_RUN_SCRIPT nsIContent* GetNextTabbableContentInScope(
 594       nsIContent* aOwner, nsIContent* aStartContent,
 595       nsIContent* aOriginalStartContent, bool aForward,
 596       int32_t aCurrentTabIndex, bool aIgnoreTabIndex,
 597       bool aForDocumentNavigation, bool aNavigateByKey, bool aSkipOwner,
 598       bool aReachedToEndForDocumentNavigation);
 599
 600   /**
 601    * Retrieve the next tabbable element in scope including aStartContent
 602    * and the scope's ancestor scopes, using focusability and tabindex to
 603    * determine the tab order.
 604    *
 605    * aStartOwner is the scope owner of the aStartContent.
 606    *
 607    * aStartContent an in/out paremeter. It as input is the starting point
 608    * for this call of this method; as output it is the shadow host in
 609    * light DOM if the next tabbable element is not found in shadow DOM,
 610    * in order to continue searching in light DOM.
 611    *
 612    * aOriginalStartContent is the initial starting point for sequential
 613    * navigation.
 614    *
 615    * aForward should be true for forward navigation or false for backward
 616    * navigation.
 617    *
 618    * aCurrentTabIndex returns tab index of shadow host in light DOM if the
 619    * next tabbable element is not found in shadow DOM, in order to continue
 620    * searching in light DOM.
 621    *
 622    * aIgnoreTabIndex to ignore the current tabindex and find the element
 623    * irrespective or the tab index.
 624    *
 625    * aForDocumentNavigation informs whether we're navigating only through
 626    * documents.
 627    *
 628    * aNavigateByKey to move focus by keyboard as a side effect of computing the
 629    * next target.
 630    *
 631    * aReachedToEndForDocumentNavigation is true when this is a document
 632    * navigation and the focus algorithm has reached to the end of the top-level
 633    * document.
 634    *
 635    * NOTE:
 636    *   Consider the method searches upwards in all shadow host- or slot-rooted
 637    *   flattened subtrees that contains aStartContent as non-root, except
 638    *   the flattened subtree rooted at shadow host in light DOM.
 639    */
 640   MOZ_CAN_RUN_SCRIPT nsIContent* GetNextTabbableContentInAncestorScopes(
 641       nsIContent* aStartOwner, nsCOMPtr<nsIContent>& aStartContent /* inout */,
 642       nsIContent* aOriginalStartContent, bool aForward,
 643       int32_t* aCurrentTabIndex, bool* aIgnoreTabIndex,
 644       bool aForDocumentNavigation, bool aNavigateByKey,
 645       bool aReachedToEndForDocumentNavigation);
 646
 647   /**
 648    * Retrieve the next tabbable element within a document, using focusability
 649    * and tabindex to determine the tab order. The element is returned in
 650    * aResultContent.
 651    *
 652    * aRootContent is the root node -- nodes above this will not be examined.
 653    * Typically this will be the root node of a document, but could also be
 654    * a popup node.
 655    *
 656    * aOriginalStartContent is the content which was originally the starting
 657    * node, in the case of recursive or looping calls.
 658    *
 659    * aStartContent is the starting point for this call of this method.
 660    * If aStartContent doesn't have visual representation, the next content
 661    * object, which does have a primary frame, will be used as a start.
 662    * If that content object is focusable, the method may return it.
 663    *
 664    * aForward should be true for forward navigation or false for backward
 665    * navigation.
 666    *
 667    * aCurrentTabIndex is the current tabindex.
 668    *
 669    * aIgnoreTabIndex to ignore the current tabindex and find the element
 670    * irrespective or the tab index. This will be true when a selection is
 671    * active, since we just want to focus the next element in tree order
 672    * from where the selection is. Similarly, if the starting element isn't
 673    * focusable, since it doesn't really have a defined tab index.
 674    *
 675    * aSkipPopover should be true to avoid an invoker triggering to step into
 676    * the popover that was already been visited again.
 677    *
 678    * aNavigateByKey to move focus by keyboard as a side effect of computing the
 679    * next target.
 680    *
 681    * aReachedToEndForDocumentNavigation is true when this is a document
 682    * navigation and the focus algorithm has reached to the end of the top-level
 683    * document.
 684    */
 685   MOZ_CAN_RUN_SCRIPT nsresult GetNextTabbableContent(
 686       mozilla::PresShell* aPresShell, nsIContent* aRootContent,
 687       nsIContent* aOriginalStartContent, nsIContent* aStartContent,
 688       bool aForward, int32_t aCurrentTabIndex, bool aIgnoreTabIndex,
 689       bool aForDocumentNavigation, bool aNavigateByKey, bool aSkipPopover,
 690       bool aReachedToEndForDocumentNavigation, nsIContent** aResultContent);
 691
 692   /**
 693    * Get the next tabbable image map area and returns it.
 694    *
 695    * aForward should be true for forward navigation or false for backward
 696    * navigation.
 697    *
 698    * aCurrentTabIndex is the current tabindex.
 699    *
 700    * aImageContent is the image.
 701    *
 702    * aStartContent is the current image map area.
 703    */
 704   nsIContent* GetNextTabbableMapArea(bool aForward, int32_t aCurrentTabIndex,
 705                                      mozilla::dom::Element* aImageContent,
 706                                      nsIContent* aStartContent);
 707
 708   /**
 709    * Return the next valid tabindex value after aCurrentTabIndex, if aForward
 710    * is true, or the previous tabindex value if aForward is false. aParent is
 711    * the node from which to start looking for tab indicies.
 712    */
 713   int32_t GetNextTabIndex(nsIContent* aParent, int32_t aCurrentTabIndex,
 714                           bool aForward);
 715
 716   /**
 717    * Focus the first focusable content within the document with a root node of
 718    * aRootContent. For content documents, this will be aRootContent itself, but
 719    * for chrome documents, this will locate the next focusable content.
 720    *
 721    * aReachedToEndForDocumentNavigation is true when the focus algorithm has
 722    * reached to the end of the top-level document.
 723    */
 724   MOZ_CAN_RUN_SCRIPT nsresult
 725   FocusFirst(mozilla::dom::Element* aRootContent, nsIContent** aNextContent,
 726              bool aReachedToEndForDocumentNavigation);
 727
 728   /**
 729    * Retrieves and returns the root node from aDocument to be focused. Will
 730    * return null if the root node cannot be focused. There are several reasons
 731    * for this:
 732    *
 733    * - if aForDocumentNavigation is false and aWindow is a chrome shell.
 734    * - if aCheckVisibility is true and the aWindow is not visible.
 735    * - if aDocument is a frameset document.
 736    */
 737   mozilla::dom::Element* GetRootForFocus(nsPIDOMWindowOuter* aWindow,
 738                                          Document* aDocument,
 739                                          bool aForDocumentNavigation,
 740                                          bool aCheckVisibility);
 741
 742   /**
 743    * Retrieves and returns the root node as with GetRootForFocus but only if
 744    * aContent is a frame with a valid child document.
 745    */
 746   mozilla::dom::Element* GetRootForChildDocument(nsIContent* aContent);
 747
 748   /**
 749    * Retreives a focusable element within the current selection of aWindow.
 750    * Currently, this only detects links.
 751    *
 752    * This is used when MoveFocus is called with a type of MOVEFOCUS_CARET,
 753    * which is used, for example, to focus links as the caret is moved over
 754    * them.
 755    */
 756   void GetFocusInSelection(nsPIDOMWindowOuter* aWindow,
 757                            nsIContent* aStartSelection,
 758                            nsIContent* aEndSelection,
 759                            nsIContent** aFocusedContent);
 760
 761  private:
 762   // Notify that the focus state of aElement has changed.  Note that we need to
 763   // pass in whether the window should show a focus ring before the
 764   // SetFocusedNode call on it happened when losing focus and after the
 765   // SetFocusedNode call when gaining focus, which is why that information needs
 766   // to be an explicit argument instead of just passing in the window and asking
 767   // it whether it should show focus rings: in the losing focus case that
 768   // information could be wrong.
 769   //
 770   // aShouldShowFocusRing is only relevant if aGettingFocus is true.
 771   static void NotifyFocusStateChange(mozilla::dom::Element* aElement,
 772                                      mozilla::dom::Element* aElementToFocus,
 773                                      int32_t aFlags, bool aGettingFocus,
 774                                      bool aShouldShowFocusRing);
 775
 776   void SetFocusedWindowInternal(nsPIDOMWindowOuter* aWindow, uint64_t aActionId,
 777                                 bool aSyncBrowsingContext = true);
 778
 779   MOZ_CAN_RUN_SCRIPT bool TryDocumentNavigation(nsIContent* aCurrentContent,
 780                                                 bool* aCheckSubDocument,
 781                                                 nsIContent** aResultContent);
 782
 783   MOZ_CAN_RUN_SCRIPT bool TryToMoveFocusToSubDocument(
 784       nsIContent* aCurrentContent, nsIContent* aOriginalStartContent,
 785       bool aForward, bool aForDocumentNavigation, bool aNavigateByKey,
 786       bool aReachedToEndForDocumentNavigation, nsIContent** aResultContent);
 787
 788   // Sets the focused BrowsingContext and, if appropriate, syncs it to
 789   // other processes.
 790   void SetFocusedBrowsingContext(mozilla::dom::BrowsingContext* aContext,
 791                                  uint64_t aActionId);
 792
 793   // Content-only
 794   // Called when receiving an IPC message about another process setting
 795   // the focused BrowsingContext.
 796   void SetFocusedBrowsingContextFromOtherProcess(
 797       mozilla::dom::BrowsingContext* aContext, uint64_t aActionId);
 798
 799   // Chrome-only
 800   // When returning true, sets the chrome process notion of what
 801   // BrowsingContext is focused in content. When returning false,
 802   // ignores the attempt to set as out-of-sequence.
 803   bool SetFocusedBrowsingContextInChrome(
 804       mozilla::dom::BrowsingContext* aContext, uint64_t aActionId);
 805
 806   void InsertNewFocusActionId(uint64_t aActionId);
 807
 808   bool ProcessPendingActiveBrowsingContextActionId(uint64_t aActionId,
 809                                                    bool aSettingToNonNull);
 810
 811   bool ProcessPendingFocusedBrowsingContextActionId(uint64_t aActionId);
 812
 813  public:
 814   // Chrome-only
 815   // Gets the chrome process notion of what BrowsingContext is focused
 816   // in content.
 817   mozilla::dom::BrowsingContext* GetFocusedBrowsingContextInChrome();
 818
 819   // Chrome-only
 820   // Notifies the focus manager that BrowsingContext::Detach was called
 821   // on a BrowsingContext so that pointers to it can be forgotten.
 822   void BrowsingContextDetached(mozilla::dom::BrowsingContext* aContext);
 823
 824  private:
 825   // Content-only
 826   // Sets the BrowsingContext corresponding to top-level Web content
 827   // in the frontmost tab if focus is in Web content.
 828   void SetActiveBrowsingContextInContent(
 829       mozilla::dom::BrowsingContext* aContext, uint64_t aActionId);
 830
 831   // Content-only
 832   // Receives notification of another process setting the top-level Web
 833   // content as being in the frontmost tab with focus in Web content.
 834   void SetActiveBrowsingContextFromOtherProcess(
 835       mozilla::dom::BrowsingContext* aContext, uint64_t aActionId);
 836
 837   // Content-only
 838   // Receives notification that another process determined that focus
 839   // moved to chrome so a particular BrowsingContext is no longer the
 840   // "active" one.
 841   void UnsetActiveBrowsingContextFromOtherProcess(
 842       mozilla::dom::BrowsingContext* aContext, uint64_t aActionId);
 843
 844   // Content-only
 845   // Receives a notification from parent that this content process's
 846   // attempt to set the active browsing context was late and the
 847   // prevailing browsing context is instead the second argument of
 848   // this method call. This should be ignored if the first argument
 849   // doesn't match the latest action id associated with setting the
 850   // active browsing context in this process, because in that case,
 851   // this revision is late.
 852   void ReviseActiveBrowsingContext(uint64_t aOldActionId,
 853                                    mozilla::dom::BrowsingContext* aContext,
 854                                    uint64_t aNewActionId);
 855
 856   // Receives a notification from parent that this content process's
 857   // attempt to set the focused browsing context was late and the
 858   // prevailing browsing context is instead the second argument of
 859   // this method call. This should be ignored if the first argument
 860   // doesn't match the latest action id associated with setting the
 861   // active browsing context in this process, because in that case,
 862   // this revision is late.
 863   void ReviseFocusedBrowsingContext(uint64_t aOldActionId,
 864                                     mozilla::dom::BrowsingContext* aContext,
 865                                     uint64_t aNewActionId);
 866
 867   // Chrome-only
 868   // Sets the chrome process notion of what content believes to be
 869   // the top-level BrowsingContext in the frontmost tab when focus
 870   // is in Web content.
 871   // Returns true if set and false if ignored.
 872   bool SetActiveBrowsingContextInChrome(mozilla::dom::BrowsingContext* aContext,
 873                                         uint64_t aActionId);
 874
 875  public:
 876   // Chrome-only
 877   // Gets the chrome process notion of what content believes to be
 878   // the top-level BrowsingContext in the frontmost tab when focus
 879   // is in Web content.
 880   mozilla::dom::BrowsingContext* GetActiveBrowsingContextInChrome();
 881
 882   uint64_t GetActionIdForActiveBrowsingContextInChrome() const;
 883
 884   uint64_t GetActionIdForFocusedBrowsingContextInChrome() const;
 885
 886   static uint64_t GenerateFocusActionId();
 887
 888   // This function works very similar to
 889   // https://html.spec.whatwg.org/#get-the-focusable-area
 890   static mozilla::dom::Element* GetTheFocusableArea(
 891       mozilla::dom::Element* aTarget, uint32_t aFlags);
 892
 893   // Returns true if it's an area element with one or more shapes that are
 894   // focusable areas.
 895   static bool IsAreaElementFocusable(mozilla::dom::HTMLAreaElement& aArea);
 896
 897  private:
 898   // In the chrome process, the currently active and front-most top-most
 899   // window. Not supposed to be used in a meaningful way in content
 900   // processes. For legacy reasons, this exists as a separate field
 901   // instead of being derived from mFocusedWindow when needed, because
 902   // the defined relation that mActiveWindow is supposed to be the same
 903   // as or ancestor of mFocusedWindow is temporarily broken when a
 904   // window is being raised or lowered.
 905   nsCOMPtr<nsPIDOMWindowOuter> mActiveWindow;
 906
 907   // In a content process, the BrowsingContext corresponding to top-level
 908   // Web content in the active tab or nullptr if focus is not in a
 909   // BrowsingContextGroup that this process participates in. Synced
 910   // across processes in a BrowsingContextGroup. This field exists
 911   // separately from mFocusedBrowsingContextInContent instead of being being
 912   // derived from it, because for legacy reasons the relation
 913   // mFocusedBrowsingContextInContent->Top() == mActiveBrowsingContextInContent
 914   // is temporarily broken when a window is being raised or lowered.
 915   // Not supposed to be used in a meaningful way in the chrome process.
 916   RefPtr<mozilla::dom::BrowsingContext> mActiveBrowsingContextInContent;
 917
 918   // If this content process set mActiveBrowsingContextInContent, this
 919   // field holds the corresponding actionId so that
 920   // mActiveBrowsingContextInContent can be revised of the parent rejects
 921   // the update. This field is used for accepting revisions only if nothing
 922   // else has updated mActiveBrowsingContextInContent before the revision
 923   // arrives.
 924   uint64_t mActionIdForActiveBrowsingContextInContent;
 925
 926   uint64_t mActionIdForActiveBrowsingContextInChrome;
 927
 928   // If this content process set mFocusedBrowsingContextInContent, this
 929   // field holds the corresponding actionId so that
 930   // mFocusedBrowsingContextInContent can be revised of the parent rejects
 931   // the update. This field is used for accepting revisions only if nothing
 932   // else has updated mFocusedBrowsingContextInContent before the revision
 933   // arrives.
 934   uint64_t mActionIdForFocusedBrowsingContextInContent;
 935
 936   uint64_t mActionIdForFocusedBrowsingContextInChrome;
 937
 938   // Whether or not mActiveBrowsingContextInContent was set from another process
 939   // or from this process.
 940   bool mActiveBrowsingContextInContentSetFromOtherProcess;
 941
 942   // This is the chrome process notion of content's
 943   // mActiveBrowsingContextInContent. Avoiding field reuse for different
 944   // semantics in different process types to make it easier to catch bugs.
 945   RefPtr<mozilla::dom::BrowsingContext> mActiveBrowsingContextInChrome;
 946
 947   // the child or top-level window that is currently focused. In the chrome
 948   // process, when a window isn't being raised or lowered, this window will
 949   // either be the same window as mActiveWindow or a descendant of it.
 950   // Except during shutdown use SetFocusedWindowInternal to set mFocusedWindow!
 951   nsCOMPtr<nsPIDOMWindowOuter> mFocusedWindow;
 952
 953   // The focused BrowsingContext if this is a chrome process and focus is
 954   // in chrome or if this is a content process and focus is in Web content
 955   // in this BrowsingContextGroup. nullptr otherwise.
 956   // Except during shutdown, must be set via SetFocusedWindowInternal which
 957   // calls SetFocusedBrowsingContext or if the value is coming in via IPC
 958   // via SetFocusedBrowsingContextFromOtherProcess.
 959   RefPtr<mozilla::dom::BrowsingContext> mFocusedBrowsingContextInContent;
 960
 961   // This is the chrome process notion of content's
 962   // mFocusedBrowsingContextInContent. Avoiding field reuse for different
 963   // semantics in different process types to make it easier to catch bugs.
 964   RefPtr<mozilla::dom::BrowsingContext> mFocusedBrowsingContextInChrome;
 965
 966   // the currently focused content if in-process or the XUL browser in which
 967   // Web content focus resides. Always inside mFocusedWindow. When a window
 968   // isn't being raised or lowered, this is a cached copy of the
 969   // mFocusedWindow's current content. This may be null if no content is
 970   // focused.
 971   RefPtr<mozilla::dom::Element> mFocusedElement;
 972
 973   // these fields store a content node temporarily while it is being focused
 974   // or blurred to ensure that a recursive call doesn't refire the same event.
 975   // They will always be cleared afterwards.
 976   RefPtr<mozilla::dom::Element> mFirstBlurEvent;
 977   RefPtr<mozilla::dom::Element> mFirstFocusEvent;
 978
 979   // keep track of a window while it is being lowered
 980   nsCOMPtr<nsPIDOMWindowOuter> mWindowBeingLowered;
 981
 982   // synchronized actions cannot be interrupted with events, so queue these up
 983   // and fire them later.
 984   nsTArray<nsDelayedBlurOrFocusEvent> mDelayedBlurFocusEvents;
 985
 986   // Array of focus action ids for which we haven't seen an active browsing
 987   // context set yet. As set is allowed to overwrite an unset. Therefore,
 988   // an unset removes earlier ids but not the matching id. A set removes
 989   // earlier ids and the matching id.
 990   //
 991   // Conceptually, active browsing context shouldn't have to exist as a
 992   // field, because it should be possible to always derive it from the
 993   // focused browsing context. Unfortunately, for legacy reasons, this
 994   // is not the case while a window is being raised or lowered.
 995   //
 996   // Conceptually, it should be possible for the parent to manage the
 997   // active browsing context. Unfortunately, for legacy reasons, the
 998   // code for setting the active browsing context needs to reside in
 999   // the content process to retain the existing and test-passing code
1000   // flow.
1001   //
1002   // This, obviously, raises the issue of content processes racing to
1003   // set the active browsing context. In particular, there is a pattern
1004   // that the parent initiates actions that cause multiple content
1005   // processes to mutate the active browsing context at almost the
1006   // same time. When two native browser windows change order, the
1007   // lowering isn't distinguished from the case of lowering the
1008   // entire app. For this reason, the owner of the previous active
1009   // browsing context tries to unset it and at almost the same time
1010   // the another content process sets a new active browsing context.
1011   // If the IPC messages for these unset and set actions were to
1012   // arrive in the wrong order, this could get in the wrong state.
1013   //
1014   // To address this issue, the parent manages an authortative order
1015   // of attempts to (un)set the active browsing context using the
1016   // array mPendingActiveBrowsingContextActions.
1017   //
1018   // A process reserves a slot in the order by calling
1019   // GenerateFocusActionId(). Per one call to GenerateFocusActionId(),
1020   // there may be at most one action to set the active browsing context
1021   // to a new value. There may be logically prior attempts to unset it
1022   // (i.e. set it to nullptr). That is, if there are both attempts to
1023   // unset and set the active browsing context with the same action id,
1024   // the attempt to set to a non-null value wins.
1025   //
1026   // The completion of an action from reserting the slot in the order
1027   // and actually performing the setting of the active browsing context
1028   // may span multiple processes and IPC messages.
1029   //
1030   // The at-most-once property is not asserted, because the process
1031   // claiming the position in the order and the process setting the
1032   // active browsing context with that actionId may be different, and
1033   // the act of using an actionId to set the active browsing context
1034   // is used to delete stale items from the array to avoid excessive
1035   // growth of the array.
1036   nsTArray<uint64_t> mPendingActiveBrowsingContextActions;
1037
1038   // Like mPendingActiveBrowsingContextActions but for the focused
1039   // browsing context.
1040   nsTArray<uint64_t> mPendingFocusedBrowsingContextActions;
1041
1042   // If set to true, layout of the document of the event target should be
1043   // flushed before handling focus depending events.
1044   bool mEventHandlingNeedsFlush;
1045
1046   static bool sTestMode;
1047
1048   // Process-specific counter for maintaining the prosess-specific
1049   // uniqueness of actionIds.
1050   static uint64_t sFocusActionCounter;
1051
1052   // the single focus manager
1053   static mozilla::StaticRefPtr<nsFocusManager> sInstance;
1054 };
1055
1056 nsresult NS_NewFocusManager(nsIFocusManager** aResult);
1057
1058 #endif