layout/base/nsRefreshObservers.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 /*
   8  * Code to notify things that animate before a refresh, at an appropriate
   9  * refresh rate.  (Perhaps temporary, until replaced by compositor.)
  10  */
  11
  12 #ifndef LAYOUT_BASE_NSREFRESHOBSERVERS_H_
  13 #define LAYOUT_BASE_NSREFRESHOBSERVERS_H_
  14
  15 #include <functional>
  16
  17 #include "mozilla/Attributes.h"
  18 #include "mozilla/TimeStamp.h"
  19 #include "nsISupports.h"
  20
  21 class nsPresContext;
  22
  23 namespace mozilla {
  24 class AnimationEventDispatcher;
  25 class PendingFullscreenEvent;
  26 class PresShell;
  27 class RefreshDriverTimer;
  28 }  // namespace mozilla
  29
  30 /**
  31  * An abstract base class to be implemented by callers wanting to be
  32  * notified at refresh times.  When nothing needs to be painted, callers
  33  * may not be notified.
  34  */
  35 class nsARefreshObserver {
  36  public:
  37   // AddRef and Release signatures that match nsISupports.  Implementors
  38   // must implement reference counting, and those that do implement
  39   // nsISupports will already have methods with the correct signature.
  40   //
  41   // The refresh driver does NOT hold references to refresh observers
  42   // except while it is notifying them.
  43   NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
  44
  45   MOZ_CAN_RUN_SCRIPT virtual void WillRefresh(mozilla::TimeStamp aTime) = 0;
  46 };
  47
  48 /**
  49  * An abstract base class to be implemented by callers wanting to be notified
  50  * when the observing refresh driver updated mMostRecentRefresh due to active
  51  * timer changes. Callers must ensure an observer is removed before it is
  52  * destroyed.
  53  */
  54 class nsATimerAdjustmentObserver {
  55  public:
  56   virtual void NotifyTimerAdjusted(mozilla::TimeStamp aTime) = 0;
  57 };
  58
  59 /**
  60  * An abstract base class to be implemented by callers wanting to be notified
  61  * that a refresh has occurred. Callers must ensure an observer is removed
  62  * before it is destroyed.
  63  */
  64 class nsAPostRefreshObserver {
  65  public:
  66   virtual void DidRefresh() = 0;
  67 };
  68
  69 namespace mozilla {
  70
  71 /**
  72  * A wrapper for nsAPostRefreshObserver that's refcounted and might unregister
  73  * itself after firing.
  74  *
  75  * Note, while the observer unregisters itself, the registering still needs to
  76  * be done by the caller.
  77  */
  78 class ManagedPostRefreshObserver : public nsAPostRefreshObserver {
  79  public:
  80   // Whether the post-refresh observer should be unregistered after it has
  81   // fired.
  82   enum class Unregister : bool { No, Yes };
  83   using Action = std::function<Unregister(bool aWasCanceled)>;
  84   NS_INLINE_DECL_REFCOUNTING(ManagedPostRefreshObserver)
  85   ManagedPostRefreshObserver(nsPresContext*, Action&&);
  86   explicit ManagedPostRefreshObserver(nsPresContext*);
  87   void DidRefresh() override;
  88   void Cancel();
  89
  90  protected:
  91   virtual ~ManagedPostRefreshObserver();
  92   RefPtr<nsPresContext> mPresContext;
  93   Action mAction;
  94 };
  95
  96 }  // namespace mozilla
  97
  98 #endif