cc/scheduler/rate_limiter.h

   1 // Copyright 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CC_SCHEDULER_RATE_LIMITER_H_
   6 #define CC_SCHEDULER_RATE_LIMITER_H_
   7
   8 #include "base/memory/ref_counted.h"
   9
  10 namespace base { class SingleThreadTaskRunner; }
  11
  12 namespace WebKit { class WebGraphicsContext3D; }
  13
  14 namespace cc {
  15
  16 class RateLimiterClient {
  17  public:
  18   virtual void RateLimit() = 0;
  19
  20  protected:
  21   virtual ~RateLimiterClient() {}
  22 };
  23
  24 // A RateLimiter can be used to make sure that a single context does not
  25 // dominate all execution time.  To use, construct a RateLimiter class around
  26 // the context and call Start() whenever calls are made on the context outside
  27 // of normal flow control. RateLimiter will block if the context is too far
  28 // ahead of the compositor.
  29 class RateLimiter : public base::RefCounted<RateLimiter> {
  30  public:
  31   static scoped_refptr<RateLimiter> Create(
  32       WebKit::WebGraphicsContext3D* context,
  33       RateLimiterClient* client,
  34       base::SingleThreadTaskRunner* task_runner);
  35
  36   void Start();
  37
  38   // Context and client will not be accessed after Stop().
  39   void Stop();
  40
  41  private:
  42   friend class base::RefCounted<RateLimiter>;
  43
  44   RateLimiter(WebKit::WebGraphicsContext3D* context,
  45               RateLimiterClient* client,
  46               base::SingleThreadTaskRunner* task_runner);
  47   ~RateLimiter();
  48
  49   void RateLimitContext();
  50
  51   WebKit::WebGraphicsContext3D* context_;
  52   bool active_;
  53   RateLimiterClient* client_;
  54   base::SingleThreadTaskRunner* task_runner_;
  55
  56   DISALLOW_COPY_AND_ASSIGN(RateLimiter);
  57 };
  58
  59 }  // namespace cc
  60
  61 #endif  // CC_SCHEDULER_RATE_LIMITER_H_