content/browser/dom_storage/dom_storage_task_runner.h

   1 // Copyright 2013 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 CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_TASK_RUNNER_H_
   6 #define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_TASK_RUNNER_H_
   7
   8 #include "base/memory/ref_counted.h"
   9 #include "base/sequenced_task_runner.h"
  10 #include "base/threading/sequenced_worker_pool.h"
  11 #include "base/time/time.h"
  12 #include "content/common/content_export.h"
  13
  14 namespace base {
  15 class MessageLoopProxy;
  16 }
  17
  18 namespace content {
  19
  20 // DOMStorage uses two task sequences (primary vs commit) to avoid
  21 // primary access from queuing up behind commits to disk.
  22 // * Initialization, shutdown, and administrative tasks are performed as
  23 //   shutdown-blocking primary sequence tasks.
  24 // * Tasks directly related to the javascript'able interface are performed
  25 //   as shutdown-blocking primary sequence tasks.
  26 //   TODO(michaeln): Skip tasks for reading during shutdown.
  27 // * Internal tasks related to committing changes to disk are performed as
  28 //   shutdown-blocking commit sequence tasks.
  29 class CONTENT_EXPORT DOMStorageTaskRunner
  30     : public base::TaskRunner {
  31  public:
  32   enum SequenceID {
  33     PRIMARY_SEQUENCE,
  34     COMMIT_SEQUENCE
  35   };
  36
  37   // The PostTask() and PostDelayedTask() methods defined by TaskRunner
  38   // post shutdown-blocking tasks on the primary sequence.
  39   bool PostDelayedTask(const tracked_objects::Location& from_here,
  40                        const base::Closure& task,
  41                        base::TimeDelta delay) override = 0;
  42
  43   // Posts a shutdown blocking task to |sequence_id|.
  44   virtual bool PostShutdownBlockingTask(
  45       const tracked_objects::Location& from_here,
  46       SequenceID sequence_id,
  47       const base::Closure& task) = 0;
  48
  49   // The TaskRunner override returns true if the current thread is running
  50   // on the primary sequence.
  51   bool RunsTasksOnCurrentThread() const override;
  52
  53   // Returns true if the current thread is running on the given |sequence_id|.
  54   virtual bool IsRunningOnSequence(SequenceID sequence_id) const = 0;
  55   bool IsRunningOnPrimarySequence() const {
  56     return IsRunningOnSequence(PRIMARY_SEQUENCE);
  57   }
  58   bool IsRunningOnCommitSequence() const {
  59     return IsRunningOnSequence(COMMIT_SEQUENCE);
  60   }
  61
  62  protected:
  63   ~DOMStorageTaskRunner() override {}
  64 };
  65
  66 // A derived class used in chromium that utilizes a SequenceWorkerPool
  67 // under dom_storage specific SequenceTokens. The |delayed_task_loop|
  68 // is used to delay scheduling on the worker pool.
  69 class CONTENT_EXPORT DOMStorageWorkerPoolTaskRunner :
  70       public DOMStorageTaskRunner {
  71  public:
  72   DOMStorageWorkerPoolTaskRunner(
  73       base::SequencedWorkerPool* sequenced_worker_pool,
  74       base::SequencedWorkerPool::SequenceToken primary_sequence_token,
  75       base::SequencedWorkerPool::SequenceToken commit_sequence_token,
  76       base::MessageLoopProxy* delayed_task_loop);
  77
  78   bool PostDelayedTask(const tracked_objects::Location& from_here,
  79                        const base::Closure& task,
  80                        base::TimeDelta delay) override;
  81
  82   bool PostShutdownBlockingTask(const tracked_objects::Location& from_here,
  83                                 SequenceID sequence_id,
  84                                 const base::Closure& task) override;
  85
  86   bool IsRunningOnSequence(SequenceID sequence_id) const override;
  87
  88  protected:
  89   ~DOMStorageWorkerPoolTaskRunner() override;
  90
  91  private:
  92
  93   base::SequencedWorkerPool::SequenceToken IDtoToken(SequenceID id) const;
  94
  95   const scoped_refptr<base::MessageLoopProxy> message_loop_;
  96   const scoped_refptr<base::SequencedWorkerPool> sequenced_worker_pool_;
  97   base::SequencedWorkerPool::SequenceToken primary_sequence_token_;
  98   base::SequencedWorkerPool::SequenceToken commit_sequence_token_;
  99 };
 100
 101 // A derived class used in unit tests that ignores all delays so
 102 // we don't block in unit tests waiting for timeouts to expire.
 103 // There is no distinction between [non]-shutdown-blocking or
 104 // the primary sequence vs the commit sequence in the mock,
 105 // all tasks are scheduled on |message_loop| with zero delay.
 106 class CONTENT_EXPORT MockDOMStorageTaskRunner :
 107       public DOMStorageTaskRunner {
 108  public:
 109   explicit MockDOMStorageTaskRunner(base::MessageLoopProxy* message_loop);
 110
 111   bool PostDelayedTask(const tracked_objects::Location& from_here,
 112                        const base::Closure& task,
 113                        base::TimeDelta delay) override;
 114
 115   bool PostShutdownBlockingTask(const tracked_objects::Location& from_here,
 116                                 SequenceID sequence_id,
 117                                 const base::Closure& task) override;
 118
 119   bool IsRunningOnSequence(SequenceID sequence_id) const override;
 120
 121  protected:
 122   ~MockDOMStorageTaskRunner() override;
 123
 124  private:
 125   const scoped_refptr<base::MessageLoopProxy> message_loop_;
 126 };
 127
 128 }  // namespace content
 129
 130 #endif  // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_TASK_RUNNER_H_