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- // Copyright 2019 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef BASE_TASK_COMMON_SCOPED_DEFER_TASK_POSTING_H_
- #define BASE_TASK_COMMON_SCOPED_DEFER_TASK_POSTING_H_
- #include "base/base_export.h"
- #include "base/location.h"
- #include "base/macros.h"
- #include "base/sequenced_task_runner.h"
- namespace base {
- // Tracing wants to post tasks from within a trace event within PostTask, but
- // this can lead to a deadlock. Create a scope to ensure that we are posting
- // the tasks in question outside of the scope of the lock.
- // NOTE: This scope affects only the thread it is created on. All other threads
- // still can post tasks.
- //
- // TODO(altimin): It should be possible to get rid of this scope, but this
- // requires refactoring TimeDomain to ensure that TimeDomain never changes and
- // we can read current time without grabbing a lock.
- class BASE_EXPORT ScopedDeferTaskPosting {
- public:
- static void PostOrDefer(scoped_refptr<SequencedTaskRunner> task_runner,
- const Location& from_here,
- OnceClosure task,
- base::TimeDelta delay);
- static bool IsPresent();
- ScopedDeferTaskPosting();
- ~ScopedDeferTaskPosting();
- private:
- static ScopedDeferTaskPosting* Get();
- // Returns whether the |scope| was set as active, which happens only
- // when the scope wasn't set before.
- static bool Set(ScopedDeferTaskPosting* scope);
- void DeferTaskPosting(scoped_refptr<SequencedTaskRunner> task_runner,
- const Location& from_here,
- OnceClosure task,
- base::TimeDelta delay);
- struct DeferredTask {
- DeferredTask(scoped_refptr<SequencedTaskRunner> task_runner,
- Location from_here,
- OnceClosure task,
- base::TimeDelta delay);
- DeferredTask(DeferredTask&& task);
- ~DeferredTask();
- scoped_refptr<SequencedTaskRunner> task_runner;
- Location from_here;
- OnceClosure task;
- base::TimeDelta delay;
- DISALLOW_COPY_AND_ASSIGN(DeferredTask);
- };
- std::vector<DeferredTask> deferred_tasks_;
- // Scopes can be nested (e.g. ScheduleWork inside PostTasks can post a task
- // to another task runner), so we want to know whether the scope is top-level
- // or not.
- bool top_level_scope_ = false;
- DISALLOW_COPY_AND_ASSIGN(ScopedDeferTaskPosting);
- };
- } // namespace base
- #endif // BASE_TASK_COMMON_SCOPED_DEFER_TASK_POSTING_H_
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