cc/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_RATE_LIMITER_H_
   6 #define CC_RATE_LIMITER_H_
   7
   8 #include "base/memory/ref_counted.h"
   9
  10 namespace WebKit {
  11 class WebGraphicsContext3D;
  12 }
  13
  14 namespace cc {
  15
  16 class Thread;
  17
  18 class RateLimiterClient {
  19 public:
  20     virtual void rateLimit() = 0;
  21 };
  22
  23 // A RateLimiter can be used to make sure that a single context does not dominate all execution time.
  24 // To use, construct a RateLimiter class around the context and call start() whenever calls are made on the
  25 // context outside of normal flow control. RateLimiter will block if the context is too far ahead of the
  26 // compositor.
  27 class RateLimiter : public base::RefCounted<RateLimiter> {
  28 public:
  29     static scoped_refptr<RateLimiter> create(WebKit::WebGraphicsContext3D*, RateLimiterClient*, Thread*);
  30
  31     void start();
  32
  33     // Context and client will not be accessed after stop().
  34     void stop();
  35
  36 private:
  37     RateLimiter(WebKit::WebGraphicsContext3D*, RateLimiterClient*, Thread*);
  38     ~RateLimiter();
  39     friend class base::RefCounted<RateLimiter>;
  40
  41     class Task;
  42     friend class Task;
  43     void rateLimitContext();
  44
  45     WebKit::WebGraphicsContext3D* m_context;
  46     bool m_active;
  47     RateLimiterClient *m_client;
  48     Thread* m_thread;
  49 };
  50
  51 }
  52 #endif  // CC_RATE_LIMITER_H_