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