1 files changed, 290 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/InputQueue.h b/gfx/layers/apz/src/InputQueue.h
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+++ b/gfx/layers/apz/src/InputQueue.h
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+/* -*- 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 mozilla_layers_InputQueue_h
+#define mozilla_layers_InputQueue_h
+
+#include "APZUtils.h"
+#include "DragTracker.h"
+#include "InputData.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/layers/TouchCounter.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "nsTArray.h"
+
+#include <unordered_map>
+
+namespace mozilla {
+
+class InputData;
+class MultiTouchInput;
+class ScrollWheelInput;
+
+namespace layers {
+
+class AsyncPanZoomController;
+class InputBlockState;
+class CancelableBlockState;
+class TouchBlockState;
+class WheelBlockState;
+class DragBlockState;
+class PanGestureBlockState;
+class PinchGestureBlockState;
+class KeyboardBlockState;
+class AsyncDragMetrics;
+class QueuedInput;
+struct APZEventResult;
+struct APZHandledResult;
+enum class BrowserGestureResponse : bool;
+
+using InputBlockCallback = std::function<void(uint64_t aInputBlockId,
+                                              APZHandledResult aHandledResult)>;
+
+struct InputBlockCallbackInfo {
+  nsEventStatus mEagerStatus;
+  InputBlockCallback mCallback;
+};
+
+/**
+ * This class stores incoming input events, associated with "input blocks",
+ * until they are ready for handling.
+ */
+class InputQueue {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(InputQueue)
+
+ public:
+  InputQueue();
+
+  /**
+   * Notifies the InputQueue of a new incoming input event. The APZC that the
+   * input event was targeted to should be provided in the |aTarget| parameter.
+   * See the documentation on APZCTreeManager::ReceiveInputEvent for info on
+   * return values from this function.
+   */
+  APZEventResult ReceiveInputEvent(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags, InputData& aEvent,
+      const Maybe<nsTArray<TouchBehaviorFlags>>& aTouchBehaviors = Nothing());
+  /**
+   * This function should be invoked to notify the InputQueue when web content
+   * decides whether or not it wants to cancel a block of events. The block
+   * id to which this applies should be provided in |aInputBlockId|.
+   */
+  void ContentReceivedInputBlock(uint64_t aInputBlockId, bool aPreventDefault);
+  /**
+   * This function should be invoked to notify the InputQueue once the target
+   * APZC to handle an input block has been confirmed. In practice this should
+   * generally be decidable upon receipt of the input event, but in some cases
+   * we may need to query the layout engine to know for sure. The input block
+   * this applies to should be specified via the |aInputBlockId| parameter.
+   */
+  void SetConfirmedTargetApzc(
+      uint64_t aInputBlockId,
+      const RefPtr<AsyncPanZoomController>& aTargetApzc);
+  /**
+   * This function is invoked to confirm that the drag block should be handled
+   * by the APZ.
+   */
+  void ConfirmDragBlock(uint64_t aInputBlockId,
+                        const RefPtr<AsyncPanZoomController>& aTargetApzc,
+                        const AsyncDragMetrics& aDragMetrics);
+  /**
+   * This function should be invoked to notify the InputQueue of the touch-
+   * action properties for the different touch points in an input block. The
+   * input block this applies to should be specified by the |aInputBlockId|
+   * parameter. If touch-action is not enabled on the platform, this function
+   * does nothing and need not be called.
+   */
+  void SetAllowedTouchBehavior(uint64_t aInputBlockId,
+                               const nsTArray<TouchBehaviorFlags>& aBehaviors);
+  /**
+   * Adds a new touch block at the end of the input queue that has the same
+   * allowed touch behaviour flags as the the touch block currently being
+   * processed. This should only be called when processing of a touch block
+   * triggers the creation of a new touch block. Returns the input block id
+   * of the the newly-created block.
+   */
+  uint64_t InjectNewTouchBlock(AsyncPanZoomController* aTarget);
+  /**
+   * Returns the pending input block at the head of the queue, if there is one.
+   * This may return null if there all input events have been processed.
+   */
+  InputBlockState* GetCurrentBlock() const;
+  /*
+   * Returns the current pending input block as a specific kind of block. If
+   * GetCurrentBlock() returns null, these functions additionally check the
+   * mActiveXXXBlock field of the corresponding input type to see if there is
+   * a depleted but still active input block, and returns that if found. These
+   * functions may return null if no block is found.
+   */
+  TouchBlockState* GetCurrentTouchBlock() const;
+  WheelBlockState* GetCurrentWheelBlock() const;
+  DragBlockState* GetCurrentDragBlock() const;
+  PanGestureBlockState* GetCurrentPanGestureBlock() const;
+  PinchGestureBlockState* GetCurrentPinchGestureBlock() const;
+  KeyboardBlockState* GetCurrentKeyboardBlock() const;
+  /**
+   * Returns true iff the pending block at the head of the queue is a touch
+   * block and is ready for handling.
+   */
+  bool HasReadyTouchBlock() const;
+  /**
+   * If there is an active wheel transaction, returns the WheelBlockState
+   * representing the transaction. Otherwise, returns null. "Active" in this
+   * function name is the same kind of "active" as in mActiveWheelBlock - that
+   * is, new incoming wheel events will go into the "active" block.
+   */
+  WheelBlockState* GetActiveWheelTransaction() const;
+  /**
+   * Remove all input blocks from the input queue.
+   */
+  void Clear();
+  /**
+   * Whether the current pending block allows scroll handoff.
+   */
+  bool AllowScrollHandoff() const;
+  /**
+   * If there is currently a drag in progress, return whether or not it was
+   * targeted at a scrollbar. If the drag was newly-created and doesn't know,
+   * use the provided |aOnScrollbar| to populate that information.
+   */
+  bool IsDragOnScrollbar(bool aOnScrollbar);
+
+  InputBlockState* GetBlockForId(uint64_t aInputBlockId);
+
+  void AddInputBlockCallback(uint64_t aInputBlockId,
+                             InputBlockCallbackInfo&& aCallback);
+
+  void SetBrowserGestureResponse(uint64_t aInputBlockId,
+                                 BrowserGestureResponse aResponse);
+
+ private:
+  ~InputQueue();
+
+  // RAII class for automatically running a timeout task that may
+  // need to be run immediately after an event has been queued.
+  class AutoRunImmediateTimeout final {
+   public:
+    explicit AutoRunImmediateTimeout(InputQueue* aQueue);
+    ~AutoRunImmediateTimeout();
+
+   private:
+    InputQueue* mQueue;
+  };
+
+  TouchBlockState* StartNewTouchBlock(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags);
+
+  TouchBlockState* StartNewTouchBlockForLongTap(
+      const RefPtr<AsyncPanZoomController>& aTarget);
+
+  /**
+   * If animations are present for the current pending input block, cancel
+   * them as soon as possible.
+   */
+  void CancelAnimationsForNewBlock(InputBlockState* aBlock,
+                                   CancelAnimationFlags aExtraFlags = Default);
+
+  /**
+   * If we need to wait for a content response, schedule that now. Returns true
+   * if the timeout was scheduled, false otherwise.
+   */
+  bool MaybeRequestContentResponse(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      CancelableBlockState* aBlock);
+
+  APZEventResult ReceiveTouchInput(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags, const MultiTouchInput& aEvent,
+      const Maybe<nsTArray<TouchBehaviorFlags>>& aTouchBehaviors);
+  APZEventResult ReceiveMouseInput(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags, MouseInput& aEvent);
+  APZEventResult ReceiveScrollWheelInput(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags, const ScrollWheelInput& aEvent);
+  APZEventResult ReceivePanGestureInput(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags, const PanGestureInput& aEvent);
+  APZEventResult ReceivePinchGestureInput(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags, const PinchGestureInput& aEvent);
+  APZEventResult ReceiveKeyboardInput(
+      const RefPtr<AsyncPanZoomController>& aTarget,
+      TargetConfirmationFlags aFlags, const KeyboardInput& aEvent);
+
+  /**
+   * Helper function that searches mQueuedInputs for the first block matching
+   * the given id, and returns it. If |aOutFirstInput| is non-null, it is
+   * populated with a pointer to the first input in mQueuedInputs that
+   * corresponds to the block, or null if no such input was found. Note that
+   * even if there are no inputs in mQueuedInputs, this function can return
+   * non-null if the block id provided matches one of the depleted-but-still-
+   * active blocks (mActiveTouchBlock, mActiveWheelBlock, etc.).
+   */
+  InputBlockState* FindBlockForId(uint64_t aInputBlockId,
+                                  InputData** aOutFirstInput);
+  void ScheduleMainThreadTimeout(const RefPtr<AsyncPanZoomController>& aTarget,
+                                 CancelableBlockState* aBlock);
+  void MainThreadTimeout(uint64_t aInputBlockId);
+  void MaybeLongTapTimeout(uint64_t aInputBlockId);
+
+  // Returns true if there's one more queued event we need to process as a
+  // result of switching the active block back to the original touch block from
+  // the touch block for long-tap.
+  bool ProcessQueue();
+  bool CanDiscardBlock(InputBlockState* aBlock);
+  void UpdateActiveApzc(const RefPtr<AsyncPanZoomController>& aNewActive);
+
+ private:
+  // The queue of input events that have not yet been fully processed.
+  // This member must only be accessed on the controller/UI thread.
+  nsTArray<UniquePtr<QueuedInput>> mQueuedInputs;
+
+  // These are the most recently created blocks of each input type. They are
+  // "active" in the sense that new inputs of that type are associated with
+  // them. Note that these pointers may be null if no inputs of the type have
+  // arrived, or if the inputs for the type formed a complete block that was
+  // then discarded.
+  RefPtr<TouchBlockState> mActiveTouchBlock;
+  RefPtr<WheelBlockState> mActiveWheelBlock;
+  RefPtr<DragBlockState> mActiveDragBlock;
+  RefPtr<PanGestureBlockState> mActivePanGestureBlock;
+  RefPtr<PinchGestureBlockState> mActivePinchGestureBlock;
+  RefPtr<KeyboardBlockState> mActiveKeyboardBlock;
+
+  // In the case where a long-tap event triggered by keeping touching happens
+  // we need to keep both the touch block for the long-tap and the original
+  // touch block started with `touch-start`. This value holds the original block
+  // until the long-tap block is processed.
+  RefPtr<TouchBlockState> mPrevActiveTouchBlock;
+
+  // The APZC to which the last event was delivered
+  RefPtr<AsyncPanZoomController> mLastActiveApzc;
+
+  // Track touches so we know when to clear mLastActiveApzc
+  TouchCounter mTouchCounter;
+
+  // Track mouse inputs so we know if we're in a drag or not
+  DragTracker mDragTracker;
+
+  // Temporarily stores a timeout task that needs to be run as soon as
+  // as the event that triggered it has been queued.
+  RefPtr<Runnable> mImmediateTimeout;
+
+  // Maps input block ids to callbacks that will be invoked when the input block
+  // is ready for handling.
+  using InputBlockCallbackMap =
+      std::unordered_map<uint64_t, InputBlockCallbackInfo>;
+  InputBlockCallbackMap mInputBlockCallbacks;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_layers_InputQueue_h