1 files changed, 76 insertions, 0 deletions
diff --git a/gfx/layers/apz/util/InputAPZContext.h b/gfx/layers/apz/util/InputAPZContext.h
new file mode 100644
index 0000000000..2793607f04
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+++ b/gfx/layers/apz/util/InputAPZContext.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_InputAPZContext_h
+#define mozilla_layers_InputAPZContext_h
+
+#include "mozilla/EventForwards.h"
+#include "mozilla/layers/ScrollableLayerGuid.h"
+
+namespace mozilla {
+namespace layers {
+
+// InputAPZContext is used to communicate various pieces of information
+// around the codebase without having to plumb it through lots of functions
+// and codepaths. Conceptually it is attached to a WidgetInputEvent that is
+// relevant to APZ.
+//
+// There are two types of information bits propagated using this class. One
+// type is propagated "downwards" (from a process entry point like nsBaseWidget
+// or BrowserChild) into deeper code that is run during complicated operations
+// like event dispatch. The other type is information that is propagated
+// "upwards", from the deeper code back to the entry point.
+class MOZ_STACK_CLASS InputAPZContext {
+ private:
+  // State that is propagated downwards from InputAPZContext creation into
+  // "deeper" code.
+  static ScrollableLayerGuid sGuid;
+  static uint64_t sBlockId;
+  static nsEventStatus sApzResponse;
+  static bool sPendingLayerization;
+
+  // State that is set in deeper code and propagated upwards.
+  static bool sRoutedToChildProcess;
+  // True if the WidgetInputEvent was dropped (which means the event wasn't
+  // dispatched) on the main-thread.
+  static bool sDropped;
+
+ public:
+  // Functions to access downwards-propagated data
+  static ScrollableLayerGuid GetTargetLayerGuid();
+  static uint64_t GetInputBlockId();
+  static nsEventStatus GetApzResponse();
+  static bool HavePendingLayerization();
+
+  // Functions to access upwards-propagated data
+  static bool WasRoutedToChildProcess();
+
+  static bool WasDropped();
+
+  // Constructor sets the data to be propagated downwards
+  InputAPZContext(const ScrollableLayerGuid& aGuid, const uint64_t& aBlockId,
+                  const nsEventStatus& aApzResponse,
+                  bool aPendingLayerization = false);
+  ~InputAPZContext();
+
+  // Functions to set data to be propagated upwards
+  static void SetRoutedToChildProcess();
+  static void SetDropped();
+
+ private:
+  ScrollableLayerGuid mOldGuid;
+  uint64_t mOldBlockId;
+  nsEventStatus mOldApzResponse;
+  bool mOldPendingLayerization;
+
+  bool mOldRoutedToChildProcess;
+  bool mOldDropped;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif /* mozilla_layers_InputAPZContext_h */