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| -rw-r--r-- | layout/base/AccessibleCaretManager.h | 446 |
1 files changed, 446 insertions, 0 deletions
diff --git a/layout/base/AccessibleCaretManager.h b/layout/base/AccessibleCaretManager.h new file mode 100644 index 0000000000..909aeb8838 --- /dev/null +++ b/layout/base/AccessibleCaretManager.h @@ -0,0 +1,446 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef AccessibleCaretManager_h +#define AccessibleCaretManager_h + +#include "AccessibleCaret.h" + +#include "mozilla/Attributes.h" +#include "mozilla/dom/CaretStateChangedEvent.h" +#include "mozilla/dom/MouseEventBinding.h" +#include "mozilla/EnumSet.h" +#include "mozilla/EventForwards.h" +#include "mozilla/RefPtr.h" +#include "mozilla/UniquePtr.h" +#include "nsCOMPtr.h" +#include "nsCoord.h" +#include "nsIFrame.h" +#include "nsISelectionListener.h" + +class nsFrameSelection; +class nsIContent; + +struct nsPoint; + +namespace mozilla { +class PresShell; +namespace dom { +class Element; +class Selection; +} // namespace dom + +// ----------------------------------------------------------------------------- +// AccessibleCaretManager does not deal with events or callbacks directly. It +// relies on AccessibleCaretEventHub to call its public methods to do the work. +// All codes needed to interact with PresShell, Selection, and AccessibleCaret +// should be written in AccessibleCaretManager. +// +// None the public methods in AccessibleCaretManager will flush layout or style +// prior to performing its task. The caller must ensure the layout is up to +// date. +// TODO: it's unclear, whether that's true. `OnSelectionChanged` calls +// `UpdateCarets`, which may flush layout. +// +// Please see the wiki page for more information. +// https://wiki.mozilla.org/AccessibleCaret +// +class AccessibleCaretManager { + public: + // @param aPresShell may be nullptr for testing. + explicit AccessibleCaretManager(PresShell* aPresShell); + virtual ~AccessibleCaretManager() = default; + + // Called by AccessibleCaretEventHub to inform us that PresShell is destroyed. + void Terminate(); + + // The aPoint in the following public methods should be relative to root + // frame. + + // Press caret on the given point. Return NS_OK if the point is actually on + // one of the carets. + MOZ_CAN_RUN_SCRIPT + virtual nsresult PressCaret(const nsPoint& aPoint, EventClassID aEventClass); + + // Drag caret to the given point. It's required to call PressCaret() + // beforehand. + MOZ_CAN_RUN_SCRIPT + virtual nsresult DragCaret(const nsPoint& aPoint); + + // Release caret from he previous press action. It's required to call + // PressCaret() beforehand. + MOZ_CAN_RUN_SCRIPT + virtual nsresult ReleaseCaret(); + + // A quick single tap on caret on given point without dragging. + MOZ_CAN_RUN_SCRIPT + virtual nsresult TapCaret(const nsPoint& aPoint); + + // Select a word or bring up paste shortcut (if Gaia is listening) under the + // given point. + MOZ_CAN_RUN_SCRIPT + virtual nsresult SelectWordOrShortcut(const nsPoint& aPoint); + + // Handle scroll-start event. + MOZ_CAN_RUN_SCRIPT + virtual void OnScrollStart(); + + // Handle scroll-end event. + MOZ_CAN_RUN_SCRIPT + virtual void OnScrollEnd(); + + // Handle ScrollPositionChanged from nsIScrollObserver. This might be called + // at anytime, not necessary between OnScrollStart and OnScrollEnd. + MOZ_CAN_RUN_SCRIPT + virtual void OnScrollPositionChanged(); + + // Handle reflow event from nsIReflowObserver. + MOZ_CAN_RUN_SCRIPT + virtual void OnReflow(); + + // Handle blur event from nsFocusManager. + MOZ_CAN_RUN_SCRIPT + virtual void OnBlur(); + + // Handle NotifySelectionChanged event from nsISelectionListener. + // @param aReason potentially multiple of the reasons defined in + // nsISelectionListener.idl. + MOZ_CAN_RUN_SCRIPT + virtual nsresult OnSelectionChanged(dom::Document* aDoc, dom::Selection* aSel, + int16_t aReason); + // Handle key event. + MOZ_CAN_RUN_SCRIPT + virtual void OnKeyboardEvent(); + + // The canvas frame holding the accessible caret anonymous content elements + // was reconstructed, resulting in the content elements getting cloned. + virtual void OnFrameReconstruction(); + + // Update the manager with the last input source that was observed. This + // is used in part to determine if the carets should be shown or hidden. + void SetLastInputSource(uint16_t aInputSource); + + // Returns True indicating that we should disable APZ to avoid jumpy carets. + bool ShouldDisableApz() const; + + protected: + class Carets; + + // @param aPresShell may be nullptr for testing. + AccessibleCaretManager(PresShell* aPresShell, Carets aCarets); + + // This enum representing the number of AccessibleCarets on the screen. + enum class CaretMode : uint8_t { + // No caret on the screen. + None, + + // One caret, i.e. the selection is collapsed. + Cursor, + + // Two carets, i.e. the selection is not collapsed. + Selection + }; + + friend std::ostream& operator<<(std::ostream& aStream, + const CaretMode& aCaretMode); + + enum class UpdateCaretsHint : uint8_t { + // Update everything including appearance and position. + Default, + + // Update everything while respecting the old appearance. For example, if + // the caret in cursor mode is hidden due to blur, do not change its + // appearance to Normal. + RespectOldAppearance, + + // No CaretStateChangedEvent will be dispatched in the end of + // UpdateCarets(). + DispatchNoEvent, + }; + + using UpdateCaretsHintSet = mozilla::EnumSet<UpdateCaretsHint>; + + friend std::ostream& operator<<(std::ostream& aStream, + const UpdateCaretsHint& aResult); + + enum class Terminated : bool { No, Yes }; + + // This method could kill the shell, so callers to methods that call + // MaybeFlushLayout should ensure the event hub that owns us is still alive. + // + // See the mRefCnt assertions in AccessibleCaretEventHub. + // + [[nodiscard]] MOZ_CAN_RUN_SCRIPT virtual Terminated MaybeFlushLayout(); + + // Update carets based on current selection status. This function will flush + // layout, so caller must ensure the PresShell is still valid after calling + // this method. + MOZ_CAN_RUN_SCRIPT + void UpdateCarets( + const UpdateCaretsHintSet& aHints = UpdateCaretsHint::Default); + + // Force hiding all carets regardless of the current selection status, and + // dispatch CaretStateChangedEvent if one of the carets is logically-visible. + MOZ_CAN_RUN_SCRIPT + void HideCaretsAndDispatchCaretStateChangedEvent(); + + MOZ_CAN_RUN_SCRIPT + void UpdateCaretsForCursorMode(const UpdateCaretsHintSet& aHints); + + MOZ_CAN_RUN_SCRIPT + void UpdateCaretsForSelectionMode(const UpdateCaretsHintSet& aHints); + + // A helper function to update mShouldDisableApz. + void UpdateShouldDisableApz(); + + // Provide haptic / touch feedback, primarily for select on longpress. + void ProvideHapticFeedback(); + + // Get the nearest enclosing focusable frame of aFrame. + // @return focusable frame if there is any; nullptr otherwise. + nsIFrame* GetFocusableFrame(nsIFrame* aFrame) const; + + // Change focus to aFrame if it isn't nullptr. Otherwise, clear the old focus + // then re-focus the window. + MOZ_CAN_RUN_SCRIPT_BOUNDARY void ChangeFocusToOrClearOldFocus( + nsIFrame* aFrame) const; + + MOZ_CAN_RUN_SCRIPT + nsresult SelectWord(nsIFrame* aFrame, const nsPoint& aPoint) const; + MOZ_CAN_RUN_SCRIPT void SetSelectionDragState(bool aState) const; + + // Return true if the candidate string is a phone number. + bool IsPhoneNumber(nsAString& aCandidate) const; + + // Extend the current selection forwards and backwards if it's already a + // phone number. + MOZ_CAN_RUN_SCRIPT + void SelectMoreIfPhoneNumber() const; + + // Extend the current phone number selection in the requested direction. + MOZ_CAN_RUN_SCRIPT + void ExtendPhoneNumberSelection(const nsAString& aDirection) const; + + void SetSelectionDirection(nsDirection aDir) const; + + // If aDirection is eDirNext, get the frame for the range start in the first + // range from the current selection, and return the offset into that frame as + // well as the range start content and the content offset. Otherwise, get the + // frame and the offset for the range end in the last range instead. + nsIFrame* GetFrameForFirstRangeStartOrLastRangeEnd( + nsDirection aDirection, int32_t* aOutOffset, + nsIContent** aOutContent = nullptr, + int32_t* aOutContentOffset = nullptr) const; + + MOZ_CAN_RUN_SCRIPT nsresult DragCaretInternal(const nsPoint& aPoint); + nsPoint AdjustDragBoundary(const nsPoint& aPoint) const; + + // Start the selection scroll timer if the caret is being dragged out of + // the scroll port. + MOZ_CAN_RUN_SCRIPT + void StartSelectionAutoScrollTimer(const nsPoint& aPoint) const; + void StopSelectionAutoScrollTimer() const; + + void ClearMaintainedSelection() const; + + static dom::Element* GetEditingHostForFrame(const nsIFrame* aFrame); + dom::Selection* GetSelection() const; + already_AddRefed<nsFrameSelection> GetFrameSelection() const; + + MOZ_CAN_RUN_SCRIPT + nsAutoString StringifiedSelection() const; + + // Get the union of all the child frame scrollable overflow rects for aFrame, + // which is used as a helper function to restrict the area where the caret can + // be dragged. Returns the rect relative to aFrame. + static nsRect GetAllChildFrameRectsUnion(nsIFrame* aFrame); + + // Restrict the active caret's dragging position based on + // sCaretsAllowDraggingAcrossOtherCaret. If the active caret is the first + // caret, the `limit` will be the previous character of the second caret. + // Otherwise, the `limit` will be the next character of the first caret. + // + // @param aOffsets is the new position of the active caret, and it will be set + // to the `limit` when 1) sCaretsAllowDraggingAcrossOtherCaret is false and + // it's being dragged past the limit. 2) sCaretsAllowDraggingAcrossOtherCaret + // is true and the active caret's position is the same as the inactive's + // position. + // @return true if the aOffsets is suitable for changing the selection. + bool RestrictCaretDraggingOffsets(nsIFrame::ContentOffsets& aOffsets); + + // --------------------------------------------------------------------------- + // The following functions are made virtual for stubbing or mocking in gtest. + // + // @return Yes if Terminate() had been called. + virtual Terminated IsTerminated() const { + return mPresShell ? Terminated::No : Terminated::Yes; + } + + // Get caret mode based on current selection. + virtual CaretMode GetCaretMode() const; + + // @return true if aStartFrame comes before aEndFrame. + virtual bool CompareTreePosition(nsIFrame* aStartFrame, + nsIFrame* aEndFrame) const; + + // Check if the two carets is overlapping to become tilt. + // @return true if the two carets become tilt; false, otherwise. + virtual bool UpdateCaretsForOverlappingTilt(); + + // Make the two carets always tilt. + virtual void UpdateCaretsForAlwaysTilt(const nsIFrame* aStartFrame, + const nsIFrame* aEndFrame); + + // Check whether AccessibleCaret is displayable in cursor mode or not. + // @param aOutFrame returns frame of the cursor if it's displayable. + // @param aOutOffset returns frame offset as well. + virtual bool IsCaretDisplayableInCursorMode( + nsIFrame** aOutFrame = nullptr, int32_t* aOutOffset = nullptr) const; + + virtual bool HasNonEmptyTextContent(nsINode* aNode) const; + + // This function will flush layout, so caller must ensure the PresShell is + // still valid after calling this method. + // @param aPoint The event point when the user is pressing or dragging a + // caret, which is relative to the root frame. + MOZ_CAN_RUN_SCRIPT + virtual void DispatchCaretStateChangedEvent(dom::CaretChangedReason aReason, + const nsPoint* aPoint = nullptr); + + // --------------------------------------------------------------------------- + // Member variables + // + nscoord mOffsetYToCaretLogicalPosition = NS_UNCONSTRAINEDSIZE; + + // AccessibleCaretEventHub owns us by a UniquePtr. When it's destroyed, we'll + // also be destroyed. No need to worry if we outlive mPresShell. + // + // mPresShell will be set to nullptr in Terminate(). Therefore mPresShell is + // nullptr either we are in gtest or PresShell::IsDestroying() is true. + PresShell* MOZ_NON_OWNING_REF mPresShell = nullptr; + + class Carets { + public: + Carets(UniquePtr<AccessibleCaret> aFirst, + UniquePtr<AccessibleCaret> aSecond); + + Carets(Carets&&) = default; + Carets(const Carets&) = delete; + Carets& operator=(const Carets&) = delete; + + AccessibleCaret* GetFirst() const { return mFirst.get(); } + + AccessibleCaret* GetSecond() const { return mSecond.get(); } + + bool HasLogicallyVisibleCaret() const { + return mFirst->IsLogicallyVisible() || mSecond->IsLogicallyVisible(); + } + + bool HasVisuallyVisibleCaret() const { + return mFirst->IsVisuallyVisible() || mSecond->IsVisuallyVisible(); + } + + void Terminate() { + mFirst = nullptr; + mSecond = nullptr; + } + + private: + // First caret is attached to nsCaret in cursor mode, and is attached to + // selection highlight as the left caret in selection mode. + UniquePtr<AccessibleCaret> mFirst; + + // Second caret is used solely in selection mode, and is attached to + // selection highlight as the right caret. + UniquePtr<AccessibleCaret> mSecond; + }; + + Carets mCarets; + + // The caret being pressed or dragged. + AccessibleCaret* mActiveCaret = nullptr; + + // The caret mode since last update carets. + CaretMode mLastUpdateCaretMode = CaretMode::None; + + // The last input source that the event hub saw. We use this to decide whether + // or not show the carets when the selection is updated, as we want to hide + // the carets for mouse-triggered selection changes but show them for other + // input types such as touch. + uint16_t mLastInputSource = dom::MouseEvent_Binding::MOZ_SOURCE_UNKNOWN; + + // Set to true in OnScrollStart() and set to false in OnScrollEnd(). + bool mIsScrollStarted = false; + + class LayoutFlusher final { + public: + LayoutFlusher() = default; + + ~LayoutFlusher(); + + LayoutFlusher(const LayoutFlusher&) = delete; + LayoutFlusher& operator=(const LayoutFlusher&) = delete; + + MOZ_CAN_RUN_SCRIPT void MaybeFlush(const PresShell& aPresShell); + + // Set to false to disallow flushing layout in some callbacks such as + // OnReflow(), OnScrollStart(), OnScrollStart(), or + // OnScrollPositionChanged(). + bool mAllowFlushing = true; + + private: + // Whether we're flushing layout, used for sanity-checking. + bool mFlushing = false; + }; + + LayoutFlusher mLayoutFlusher; + + // Set to True if one of the caret's position is changed in last update. + bool mIsCaretPositionChanged = false; + + class DesiredAsyncPanZoomState final { + public: + void Update(const AccessibleCaretManager& aAccessibleCaretManager); + + enum class Value : bool { Disabled, Enabled }; + + Value Get() const { return mValue; } + + private: + Value mValue = Value::Enabled; + }; + + DesiredAsyncPanZoomState mDesiredAsyncPanZoomState; + + static const int32_t kAutoScrollTimerDelay = 30; + + // Clicking on the boundary of input or textarea will move the caret to the + // front or end of the content. To avoid this, we need to deflate the content + // boundary by 61 app units, which is 1 pixel + 1 app unit as defined in + // AppUnit.h. + static const int32_t kBoundaryAppUnits = 61; + + enum ScriptUpdateMode : int32_t { + // By default, always hide carets for selection changes due to JS calls. + kScriptAlwaysHide, + // Update any visible carets for selection changes due to JS calls, + // but don't show carets if carets are hidden. + kScriptUpdateVisible, + // Always show carets for selection changes due to JS calls. + kScriptAlwaysShow + }; +}; + +std::ostream& operator<<(std::ostream& aStream, + const AccessibleCaretManager::CaretMode& aCaretMode); + +std::ostream& operator<<( + std::ostream& aStream, + const AccessibleCaretManager::UpdateCaretsHint& aResult); + +} // namespace mozilla + +#endif // AccessibleCaretManager_h |