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 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* 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/. */

 #ifndef nsFocusManager_h___

 #define nsFocusManager_h___

 #include "nsCycleCollectionParticipant.h"

 #include "nsIDocument.h"

 #include "nsIFocusManager.h"

 #include "nsIObserver.h"

 #include "nsIWidget.h"

 #include "nsWeakReference.h"

 #include "mozilla/Attributes.h"

 #define FOCUSMETHOD_MASK 0xF000

 #define FOCUSMETHODANDRING_MASK 0xF0F000

 #define FOCUSMANAGER_CONTRACTID "@mozilla.org/focus-manager;1"

 class nsIContent;

 class nsIDocShellTreeItem;

 class nsPIDOMWindow;

 struct nsDelayedBlurOrFocusEvent;

 /**

  * The focus manager keeps track of where the focus is, that is, the node

  * which receives key events.

  */

 class nsFocusManager MOZ_FINAL : public nsIFocusManager,

                                  public nsIObserver,

                                  public nsSupportsWeakReference

 {

   typedef mozilla::widget::InputContextAction InputContextAction;

 public:

   NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsFocusManager, nsIFocusManager)

   NS_DECL_CYCLE_COLLECTING_ISUPPORTS

   NS_DECL_NSIOBSERVER

   NS_DECL_NSIFOCUSMANAGER

   // called to initialize and stop the focus manager at startup and shutdown

   static nsresult Init();

   static void Shutdown();

   /**

    * Retrieve the single focus manager.

    */

   static nsFocusManager* GetFocusManager() { return sInstance; }

   /**

    * A faster version of nsIFocusManager::GetFocusedElement, returning a

    * raw nsIContent pointer (instead of having AddRef-ed nsIDOMElement

    * pointer filled in to an out-parameter).

    */

   nsIContent* GetFocusedContent() { return mFocusedContent; }

   /**

    * Return a focused window. Version of nsIFocusManager::GetFocusedWindow.

    */

   nsPIDOMWindow* GetFocusedWindow() const { return mFocusedWindow; }

   /**

    * Return an active window. Version of nsIFocusManager::GetActiveWindow.

    */

   nsPIDOMWindow* GetActiveWindow() const { return mActiveWindow; }

   /**

    * Called when content has been removed.

    */

   nsresult ContentRemoved(nsIDocument* aDocument, nsIContent* aContent);

   /**

    * Called when mouse button down event handling is started and finished.

    */

   void SetMouseButtonDownHandlingDocument(nsIDocument* aDocument)

   {

     NS_ASSERTION(!aDocument || !mMouseDownEventHandlingDocument,

                  "Some mouse button down events are nested?");

     mMouseDownEventHandlingDocument = aDocument;

   }

   /**

    * Update the caret with current mode (whether in caret browsing mode or not).

    */

   void UpdateCaretForCaretBrowsingMode();

   /**

    * Returns the content node that would be focused if aWindow was in an

    * active window. This will traverse down the frame hierarchy, starting at

    * the given window aWindow. Sets aFocusedWindow to the window with the

    * document containing aFocusedContent. If no element is focused,

    * aFocusedWindow may be still be set -- this means that the document is

    * focused but no element within it is focused.

    *

    * aWindow and aFocusedWindow must both be non-null.

    */

   static nsIContent* GetFocusedDescendant(nsPIDOMWindow* aWindow, bool aDeep,

                                           nsPIDOMWindow** aFocusedWindow);

   /**

    * Returns the content node that focus will be redirected to if aContent was

    * focused. This is used for the special case of certain XUL elements such

    * as textboxes which redirect focus to an anonymous child.

    *

    * aContent must be non-null.

    *

    * XXXndeakin this should be removed eventually but I want to do that as

    * followup work.

    */

   static nsIContent* GetRedirectedFocus(nsIContent* aContent);

   /**

    * Returns an InputContextAction cause for aFlags.

    */

   static InputContextAction::Cause GetFocusMoveActionCause(uint32_t aFlags);

   static bool sMouseFocusesFormControl;

   static void MarkUncollectableForCCGeneration(uint32_t aGeneration);

 protected:

   nsFocusManager();

   ~nsFocusManager();

   /**

    * Ensure that the widget associated with the currently focused window is

    * focused at the widget level.

    */

   void EnsureCurrentWidgetFocused();

   /**

    * Blur whatever is currently focused and focus aNewContent. aFlags is a

    * bitmask of the flags defined in nsIFocusManager. If aFocusChanged is

    * true, then the focus has actually shifted and the caret position will be

    * updated to the new focus, aNewContent will be scrolled into view (unless

    * a flag disables this) and the focus method for the window will be updated.

    * If aAdjustWidget is false, don't change the widget focus state.

    *

    * All actual focus changes must use this method to do so. (as opposed

    * to those that update the focus in an inactive window for instance).

    */

   void SetFocusInner(nsIContent* aNewContent, int32_t aFlags,

                      bool aFocusChanged, bool aAdjustWidget);

   /**

    * Returns true if aPossibleAncestor is the same as aWindow or an

    * ancestor of aWindow.

    */

   bool IsSameOrAncestor(nsPIDOMWindow* aPossibleAncestor,

                           nsPIDOMWindow* aWindow);

   /**

    * Returns the window that is the lowest common ancestor of both aWindow1

    * and aWindow2, or null if they share no common ancestor.

    */

   already_AddRefed<nsPIDOMWindow> GetCommonAncestor(nsPIDOMWindow* aWindow1,

                                                     nsPIDOMWindow* aWindow2);

   /**

    * When aNewWindow is focused, adjust the ancestors of aNewWindow so that they

    * also have their corresponding frames focused. Thus, one can start at

    * the active top-level window and navigate down the currently focused

    * elements for each frame in the tree to get to aNewWindow.

    */

   void AdjustWindowFocus(nsPIDOMWindow* aNewWindow, bool aCheckPermission);

   /**

    * Returns true if aWindow is visible.

    */

   bool IsWindowVisible(nsPIDOMWindow* aWindow);

   /**

    * Returns true if aContent is a root element and not focusable.

    * I.e., even if aContent is editable root element, this returns true when

    * the document is in designMode.

    *

    * @param aContent must not be null and must be in a document.

    */

   bool IsNonFocusableRoot(nsIContent* aContent);

   /**

    * Checks and returns aContent if it may be focused, another content node if

    * the focus should be retargeted at another node, or null if the node

    * cannot be focused. aFlags are the flags passed to SetFocus and similar

    * methods.

    *

    * An element is focusable if it is in a document, the document isn't in

    * print preview mode and the element has an nsIFrame where the

    * CheckIfFocusable method returns true. For <area> elements, there is no

    * frame, so only the IsFocusable method on the content node must be

    * true.

    */

   nsIContent* CheckIfFocusable(nsIContent* aContent, uint32_t aFlags);

   /**

    * Blurs the currently focused element. Returns false if another element was

    * focused as a result. This would mean that the caller should not proceed

    * with a pending call to Focus. Normally, true would be returned.

    *

    * The currently focused element within aWindowToClear will be cleared.

    * aWindowToClear may be null, which means that no window is cleared. This

    * will be the case, for example, when lowering a window, as we want to fire

    * a blur, but not actually change what element would be focused, so that

    * the same element will be focused again when the window is raised.

    *

    * aAncestorWindowToFocus should be set to the common ancestor of the window

    * that is being blurred and the window that is going to focused, when

    * switching focus to a sibling window.

    *

    * aIsLeavingDocument should be set to true if the document/window is being

    * blurred as well. Document/window blur events will be fired. It should be

    * false if an element is the same document is about to be focused.

    *

    * If aAdjustWidget is false, don't change the widget focus state.

    */

   bool Blur(nsPIDOMWindow* aWindowToClear,

               nsPIDOMWindow* aAncestorWindowToFocus,

               bool aIsLeavingDocument,

               bool aAdjustWidget);

   /**

    * Focus an element in the active window and child frame.

    *

    * aWindow is the window containing the element aContent to focus.

    *

    * aFlags is the flags passed to the various focus methods in

    * nsIFocusManager.

    *

    * aIsNewDocument should be true if a new document is being focused.

    * Document/window focus events will be fired.

    *

    * aFocusChanged should be true if a new content node is being focused, so

    * the focused content will be scrolled into view and the caret position

    * will be updated. If false is passed, then a window is simply being

    * refocused, for instance, due to a window being raised, or a tab is being

    * switched to.

    *

    * If aFocusChanged is true, then the focus has moved to a new location.

    * Otherwise, the focus is just being updated because the window was

    * raised.

    *

    * aWindowRaised should be true if the window is being raised. In this case,

    * command updaters will not be called.

    *

    * If aAdjustWidget is false, don't change the widget focus state.

    */

   void Focus(nsPIDOMWindow* aWindow,

              nsIContent* aContent,

              uint32_t aFlags,

              bool aIsNewDocument,

              bool aFocusChanged,

              bool aWindowRaised,

              bool aAdjustWidget);

   /**

    * Fires a focus or blur event at aTarget.

    *

    * aType should be either NS_FOCUS_CONTENT or NS_BLUR_CONTENT. For blur

    * events, aFocusMethod should normally be non-zero.

    *

    * aWindowRaised should only be true if called from WindowRaised.

    */

   void SendFocusOrBlurEvent(uint32_t aType,

                             nsIPresShell* aPresShell,

                             nsIDocument* aDocument,

                             nsISupports* aTarget,

                             uint32_t aFocusMethod,

                             bool aWindowRaised,

                             bool aIsRefocus = false);

   /**

    * Scrolls aContent into view unless the FLAG_NOSCROLL flag is set.

    */

   void ScrollIntoView(nsIPresShell* aPresShell,

                       nsIContent* aContent,

                       uint32_t aFlags);

   /**

    * Raises the top-level window aWindow at the widget level.

    */

   void RaiseWindow(nsPIDOMWindow* aWindow);

   /**

    * Updates the caret positon and visibility to match the focus.

    *

    * aMoveCaretToFocus should be true to move the caret to aContent.

    *

    * aUpdateVisibility should be true to update whether the caret is

    * visible or not.

    */

   void UpdateCaret(bool aMoveCaretToFocus,

                    bool aUpdateVisibility,

                    nsIContent* aContent);

   /**

    * Helper method to move the caret to the focused element aContent.

    */

   void MoveCaretToFocus(nsIPresShell* aPresShell, nsIContent* aContent);

   /**

    * Makes the caret visible or not, depending on aVisible.

    */

   nsresult SetCaretVisible(nsIPresShell* aPresShell,

                            bool aVisible,

                            nsIContent* aContent);

   // the remaining functions are used for tab key and document-navigation

   /**

    * Retrieves the start and end points of the current selection for

    * aDocument and stores them in aStartContent and aEndContent.

    */

   nsresult GetSelectionLocation(nsIDocument* aDocument,

                                 nsIPresShell* aPresShell,

                                 nsIContent **aStartContent,

                                 nsIContent **aEndContent);

   /**

    * Helper function for MoveFocus which determines the next element

    * to move the focus to and returns it in aNextContent.

    *

    * aWindow is the window to adjust the focus within, and aStart is

    * the element to start navigation from. For tab key navigation,

    * this should be the currently focused element.

    *

    * aType is the type passed to MoveFocus. If aNoParentTraversal is set,

    * navigation is not done to parent documents and iteration returns to the

    * beginning (or end) of the starting document.

    */

   nsresult DetermineElementToMoveFocus(nsPIDOMWindow* aWindow,

                                        nsIContent* aStart,

                                        int32_t aType, bool aNoParentTraversal,

                                        nsIContent** aNextContent);

   /**

    * Retrieve the next tabbable element within a document, using focusability

    * and tabindex to determine the tab order. The element is returned in

    * aResultContent.

    *

    * aRootContent is the root node -- nodes above this will not be examined.

    * Typically this will be the root node of a document, but could also be

    * a popup node.

    *

    * aOriginalStartContent is the content which was originally the starting

    * node, in the case of recursive or looping calls.

    *

    * aStartContent is the starting point for this call of this method.

    * If aStartContent doesn't have visual representation, the next content

    * object, which does have a primary frame, will be used as a start.

    * If that content object is focusable, the method may return it.

    *

    * aForward should be true for forward navigation or false for backward

    * navigation.

    *

    * aCurrentTabIndex is the current tabindex.

    *

    * aIgnoreTabIndex to ignore the current tabindex and find the element

    * irrespective or the tab index. This will be true when a selection is

    * active, since we just want to focus the next element in tree order

    * from where the selection is. Similarly, if the starting element isn't

    * focusable, since it doesn't really have a defined tab index.

    */

   nsresult GetNextTabbableContent(nsIPresShell* aPresShell,

                                   nsIContent* aRootContent,

                                   nsIContent* aOriginalStartContent,

                                   nsIContent* aStartContent,

                                   bool aForward,

                                   int32_t aCurrentTabIndex,

                                   bool aIgnoreTabIndex,

                                   nsIContent** aResultContent);

   /**

    * Get the next tabbable image map area and returns it.

    *

    * aForward should be true for forward navigation or false for backward

    * navigation.

    *

    * aCurrentTabIndex is the current tabindex.

    *

    * aImageContent is the image.

    *

    * aStartContent is the current image map area.

    */

   nsIContent* GetNextTabbableMapArea(bool aForward,

                                      int32_t aCurrentTabIndex,

                                      nsIContent* aImageContent,

                                      nsIContent* aStartContent);

   /**

    * Return the next valid tabindex value after aCurrentTabIndex, if aForward

    * is true, or the previous tabindex value if aForward is false. aParent is

    * the node from which to start looking for tab indicies.

    */

   int32_t GetNextTabIndex(nsIContent* aParent,

                           int32_t aCurrentTabIndex,

                           bool aForward);

   /**

    * Retrieves and returns the root node from aDocument to be focused. Will

    * return null if the root node cannot be focused. There are several reasons

    * for this:

    *

    * - if aIsForDocNavigation is true, and aWindow is in an <iframe>.

    * - if aIsForDocNavigation is false, and aWindow is a chrome shell.

    * - if aCheckVisibility is true and the aWindow is not visible.

    * - if aDocument is a frameset document.

    */

   nsIContent* GetRootForFocus(nsPIDOMWindow* aWindow,

                               nsIDocument* aDocument,

                               bool aIsForDocNavigation,

                               bool aCheckVisibility);

   /**

    * Get the last docshell child of aItem and return it in aResult.

    */

   void GetLastDocShell(nsIDocShellTreeItem* aItem,

                        nsIDocShellTreeItem** aResult);

   /**

    * Get the next docshell child of aItem and return it in aResult.

    */

   void GetNextDocShell(nsIDocShellTreeItem* aItem,

                        nsIDocShellTreeItem** aResult);

   /**

    * Get the previous docshell child of aItem and return it in aResult.

    */

   void GetPreviousDocShell(nsIDocShellTreeItem* aItem,

                            nsIDocShellTreeItem** aResult);

   /**

    * Determine the first panel with focusable content in document tab order

    * from the given document. aForward indicates the direction to scan. If

    * aCurrentPopup is set to a panel, the next or previous popup after

    * aCurrentPopup after it is used. If aCurrentPopup is null, then the first

    * or last popup is used. If a panel has no focusable content, it is skipped.

    * Null is returned if no panel is open or no open panel contains a focusable

    * element.

    */

   nsIContent* GetNextTabbablePanel(nsIDocument* aDocument, nsIFrame* aCurrentPopup, bool aForward);

   /**

    * Get the tabbable next document from aStartContent or, if null, the

    * currently focused frame if aForward is true, or the previously tabbable

    * document if aForward is false. If this document is a chrome or frameset

    * document, returns the first focusable element within this document,

    * otherwise, returns the root node of the document.

    *

    *

    * Panels with focusable content are also placed in the cycling order, just

    * after the document containing that panel.

    *

    * This method would be used for document navigation, which is typically

    * invoked by pressing F6.

    */

   nsIContent* GetNextTabbableDocument(nsIContent* aStartContent, bool aForward);

   /**

    * Retreives a focusable element within the current selection of aWindow.

    * Currently, this only detects links.

    *  

    * This is used when MoveFocus is called with a type of MOVEFOCUS_CARET,

    * which is used, for example, to focus links as the caret is moved over

    * them.

    */

   void GetFocusInSelection(nsPIDOMWindow* aWindow,

                            nsIContent* aStartSelection,

                            nsIContent* aEndSelection,

                            nsIContent** aFocusedContent);

 private:

   // Notify that the focus state of aContent has changed.  Note that

   // we need to pass in whether the window should show a focus ring

   // before the SetFocusedNode call on it happened when losing focus

   // and after the SetFocusedNode call when gaining focus, which is

   // why that information needs to be an explicit argument instead of

   // just passing in the window and asking it whether it should show

   // focus rings: in the losing focus case that information could be

   // wrong..

   static void NotifyFocusStateChange(nsIContent* aContent,

                                      bool aWindowShouldShowFocusRing,

                                      bool aGettingFocus);

   void SetFocusedWindowInternal(nsPIDOMWindow* aWindow);

   // the currently active and front-most top-most window

   nsCOMPtr<nsPIDOMWindow> mActiveWindow;

   // the child or top-level window that is currently focused. This window will

   // either be the same window as mActiveWindow or a descendant of it.

   // Except during shutdown use SetFocusedWindowInternal to set mFocusedWindow!

   nsCOMPtr<nsPIDOMWindow> mFocusedWindow;

   // the currently focused content, which is always inside mFocusedWindow. This

   // is a cached copy of the mFocusedWindow's current content. This may be null

   // if no content is focused.

   nsCOMPtr<nsIContent> mFocusedContent;

   // these fields store a content node temporarily while it is being focused

   // or blurred to ensure that a recursive call doesn't refire the same event.

   // They will always be cleared afterwards.

   nsCOMPtr<nsIContent> mFirstBlurEvent;

   nsCOMPtr<nsIContent> mFirstFocusEvent;

   // keep track of a window while it is being lowered

   nsCOMPtr<nsPIDOMWindow> mWindowBeingLowered;

   // synchronized actions cannot be interrupted with events, so queue these up

   // and fire them later.

   nsTArray<nsDelayedBlurOrFocusEvent> mDelayedBlurFocusEvents;

   // A document which is handling a mouse button down event.

   // When a mouse down event process is finished, ESM sets focus to the target

   // content.  Therefore, while DOM event handlers are handling mouse down

   // events, the handlers should be able to steal focus from any elements even

   // if focus is in chrome content.  So, if this isn't nullptr and the caller

   // can access the document node, the caller should succeed in moving focus.

   nsCOMPtr<nsIDocument> mMouseDownEventHandlingDocument;

   static bool sTestMode;

   // the single focus manager

   static nsFocusManager* sInstance;

 };

 nsresult

 NS_NewFocusManager(nsIFocusManager** aResult);

 #endif