dom/base/AnimationFrameProvider.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_AnimationFrameProvider_h
   8 #define mozilla_dom_AnimationFrameProvider_h
   9
  10 #include "mozilla/dom/AnimationFrameProviderBinding.h"
  11 #include "mozilla/HashTable.h"
  12 #include "mozilla/RefPtr.h"
  13 #include "nsTArray.h"
  14
  15 namespace mozilla::dom {
  16
  17 struct FrameRequest {
  18   FrameRequest(FrameRequestCallback& aCallback, int32_t aHandle);
  19   ~FrameRequest();
  20
  21   // Comparator operators to allow RemoveElementSorted with an
  22   // integer argument on arrays of FrameRequest
  23   bool operator==(int32_t aHandle) const { return mHandle == aHandle; }
  24   bool operator<(int32_t aHandle) const { return mHandle < aHandle; }
  25
  26   RefPtr<FrameRequestCallback> mCallback;
  27   int32_t mHandle;
  28 };
  29
  30 class FrameRequestManager {
  31  public:
  32   FrameRequestManager() = default;
  33   ~FrameRequestManager() = default;
  34
  35   nsresult Schedule(FrameRequestCallback& aCallback, int32_t* aHandle);
  36   bool Cancel(int32_t aHandle);
  37
  38   bool IsEmpty() const { return mCallbacks.IsEmpty(); }
  39
  40   bool IsCanceled(int32_t aHandle) const {
  41     return !mCanceledCallbacks.empty() && mCanceledCallbacks.has(aHandle);
  42   }
  43
  44   void Take(nsTArray<FrameRequest>& aCallbacks) {
  45     aCallbacks = std::move(mCallbacks);
  46     mCanceledCallbacks.clear();
  47   }
  48
  49   void Unlink();
  50
  51   void Traverse(nsCycleCollectionTraversalCallback& aCB);
  52
  53  private:
  54   nsTArray<FrameRequest> mCallbacks;
  55
  56   // The set of frame request callbacks that were canceled but which we failed
  57   // to find in mFrameRequestCallbacks.
  58   HashSet<int32_t> mCanceledCallbacks;
  59
  60   /**
  61    * The current frame request callback handle
  62    */
  63   int32_t mCallbackCounter = 0;
  64 };
  65
  66 inline void ImplCycleCollectionUnlink(FrameRequestManager& aField) {
  67   aField.Unlink();
  68 }
  69
  70 inline void ImplCycleCollectionTraverse(
  71     nsCycleCollectionTraversalCallback& aCallback, FrameRequestManager& aField,
  72     const char* aName, uint32_t aFlags) {
  73   aField.Traverse(aCallback);
  74 }
  75
  76 }  // namespace mozilla::dom
  77
  78 #endif