1 files changed, 217 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/InputQueue.h b/gfx/layers/apz/src/InputQueue.h
new file mode 100644
index 000000000..eaf9b20bc
--- /dev/null
+++ b/gfx/layers/apz/src/InputQueue.h
@@ -0,0 +1,217 @@
+/* -*- Mode: C++; tab-width: 8; 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 mozilla_layers_InputQueue_h
+#define mozilla_layers_InputQueue_h
+
+#include "APZUtils.h"
+#include "DragTracker.h"
+#include "InputData.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "nsTArray.h"
+#include "TouchCounter.h"
+
+namespace mozilla {
+
+class InputData;
+class MultiTouchInput;
+class ScrollWheelInput;
+
+namespace layers {
+
+class AsyncPanZoomController;
+class CancelableBlockState;
+class TouchBlockState;
+class WheelBlockState;
+class DragBlockState;
+class PanGestureBlockState;
+class AsyncDragMetrics;
+class QueuedInput;
+
+/**
+ * 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, including |aOutInputBlockId|.
+   */
+  nsEventStatus ReceiveInputEvent(const RefPtr<AsyncPanZoomController>& aTarget,
+                                  bool aTargetConfirmed,
+                                  const InputData& aEvent,
+                                  uint64_t* aOutInputBlockId);
+  /**
+   * 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.
+   */
+  CancelableBlockState* 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;
+  /**
+   * 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);
+
+private:
+  ~InputQueue();
+
+  TouchBlockState* StartNewTouchBlock(const RefPtr<AsyncPanZoomController>& aTarget,
+                                      bool aTargetConfirmed,
+                                      bool aCopyPropertiesFromCurrent);
+
+  /**
+   * If animations are present for the current pending input block, cancel
+   * them as soon as possible.
+   */
+  void CancelAnimationsForNewBlock(CancelableBlockState* aBlock);
+
+  /**
+   * If we need to wait for a content response, schedule that now.
+   */
+  void MaybeRequestContentResponse(const RefPtr<AsyncPanZoomController>& aTarget,
+                                   CancelableBlockState* aBlock);
+
+  nsEventStatus ReceiveTouchInput(const RefPtr<AsyncPanZoomController>& aTarget,
+                                  bool aTargetConfirmed,
+                                  const MultiTouchInput& aEvent,
+                                  uint64_t* aOutInputBlockId);
+  nsEventStatus ReceiveMouseInput(const RefPtr<AsyncPanZoomController>& aTarget,
+                                  bool aTargetConfirmed,
+                                  const MouseInput& aEvent,
+                                  uint64_t* aOutInputBlockId);
+  nsEventStatus ReceiveScrollWheelInput(const RefPtr<AsyncPanZoomController>& aTarget,
+                                        bool aTargetConfirmed,
+                                        const ScrollWheelInput& aEvent,
+                                        uint64_t* aOutInputBlockId);
+  nsEventStatus ReceivePanGestureInput(const RefPtr<AsyncPanZoomController>& aTarget,
+                                        bool aTargetConfirmed,
+                                        const PanGestureInput& aEvent,
+                                        uint64_t* aOutInputBlockId);
+
+  /**
+   * 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.).
+   */
+  CancelableBlockState* FindBlockForId(uint64_t aInputBlockId,
+                                       InputData** aOutFirstInput);
+  void ScheduleMainThreadTimeout(const RefPtr<AsyncPanZoomController>& aTarget,
+                                 CancelableBlockState* aBlock);
+  void MainThreadTimeout(uint64_t aInputBlockId);
+  void ProcessQueue();
+  bool CanDiscardBlock(CancelableBlockState* 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;
+
+  // 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;
+};
+
+} // namespace layers
+} // namespace mozilla
+
+#endif // mozilla_layers_InputQueue_h