1 // Copyright (c) 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.
5 #ifndef BASE_DEFERRED_SEQUENCED_TASKRUNNER_H_
6 #define BASE_DEFERRED_SEQUENCED_TASKRUNNER_H_
10 #include "base/base_export.h"
11 #include "base/basictypes.h"
12 #include "base/callback.h"
13 #include "base/compiler_specific.h"
14 #include "base/memory/ref_counted.h"
15 #include "base/sequenced_task_runner.h"
16 #include "base/synchronization/lock.h"
17 #include "base/time/time.h"
18 #include "base/tracked_objects.h"
22 // A DeferredSequencedTaskRunner is a subclass of SequencedTaskRunner that
23 // queues up all requests until the first call to Start() is issued.
24 class BASE_EXPORT DeferredSequencedTaskRunner
: public SequencedTaskRunner
{
26 explicit DeferredSequencedTaskRunner(
27 const scoped_refptr
<SequencedTaskRunner
>& target_runner
);
29 // TaskRunner implementation
30 virtual bool PostDelayedTask(const tracked_objects::Location
& from_here
,
32 TimeDelta delay
) override
;
33 virtual bool RunsTasksOnCurrentThread() const override
;
35 // SequencedTaskRunner implementation
36 virtual bool PostNonNestableDelayedTask(
37 const tracked_objects::Location
& from_here
,
39 TimeDelta delay
) override
;
41 // Start the execution - posts all queued tasks to the target executor. The
42 // deferred tasks are posted with their initial delay, meaning that the task
43 // execution delay is actually measured from Start.
44 // Fails when called a second time.
52 tracked_objects::Location posted_from
;
54 // The delay this task was initially posted with.
59 virtual ~DeferredSequencedTaskRunner();
61 // Creates a |Task| object and adds it to |deferred_tasks_queue_|.
62 void QueueDeferredTask(const tracked_objects::Location
& from_here
,
65 bool is_non_nestable
);
67 // // Protects |started_| and |deferred_tasks_queue_|.
71 const scoped_refptr
<SequencedTaskRunner
> target_task_runner_
;
72 std::vector
<DeferredTask
> deferred_tasks_queue_
;
74 DISALLOW_COPY_AND_ASSIGN(DeferredSequencedTaskRunner
);
79 #endif // BASE_DEFERRED_SEQUENCED_TASKRUNNER_H_