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Unified Diff: base/task/cancelable_task_tracker.h

Issue 1647803004: Move base to DEPS (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 4 years, 11 months ago
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Index: base/task/cancelable_task_tracker.h
diff --git a/base/task/cancelable_task_tracker.h b/base/task/cancelable_task_tracker.h
deleted file mode 100644
index b8a8b70e333922b41d5e7019070f09e18a6a12e4..0000000000000000000000000000000000000000
--- a/base/task/cancelable_task_tracker.h
+++ /dev/null
@@ -1,140 +0,0 @@
-// Copyright 2014 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.
-
-// CancelableTaskTracker posts tasks (in the form of a Closure) to a
-// TaskRunner, and is able to cancel the task later if it's not needed
-// anymore. On destruction, CancelableTaskTracker will cancel all
-// tracked tasks.
-//
-// Each cancelable task can be associated with a reply (also a Closure). After
-// the task is run on the TaskRunner, |reply| will be posted back to
-// originating TaskRunner.
-//
-// NOTE:
-//
-// CancelableCallback (base/cancelable_callback.h) and WeakPtr binding are
-// preferred solutions for canceling a task. However, they don't support
-// cancelation from another thread. This is sometimes a performance critical
-// requirement. E.g. We need to cancel database lookup task on DB thread when
-// user changes inputed text. If it is performance critical to do a best effort
-// cancelation of a task, then CancelableTaskTracker is appropriate,
-// otherwise use one of the other mechanisms.
-//
-// THREAD-SAFETY:
-//
-// 1. CancelableTaskTracker objects are not thread safe. They must
-// be created, used, and destroyed on the originating thread that posts the
-// task. It's safe to destroy a CancelableTaskTracker while there
-// are outstanding tasks. This is commonly used to cancel all outstanding
-// tasks.
-//
-// 2. Both task and reply are deleted on the originating thread.
-//
-// 3. IsCanceledCallback is thread safe and can be run or deleted on any
-// thread.
-#ifndef BASE_TASK_CANCELABLE_TASK_TRACKER_H_
-#define BASE_TASK_CANCELABLE_TASK_TRACKER_H_
-
-#include "base/base_export.h"
-#include "base/basictypes.h"
-#include "base/callback.h"
-#include "base/containers/hash_tables.h"
-#include "base/memory/weak_ptr.h"
-#include "base/task_runner_util.h"
-#include "base/threading/thread_checker.h"
-
-namespace tracked_objects {
-class Location;
-} // namespace tracked_objects
-
-namespace base {
-
-class CancellationFlag;
-class TaskRunner;
-
-class BASE_EXPORT CancelableTaskTracker {
- public:
- // All values except kBadTaskId are valid.
- typedef int64 TaskId;
- static const TaskId kBadTaskId;
-
- typedef base::Callback<bool()> IsCanceledCallback;
-
- CancelableTaskTracker();
-
- // Cancels all tracked tasks.
- ~CancelableTaskTracker();
-
- TaskId PostTask(base::TaskRunner* task_runner,
- const tracked_objects::Location& from_here,
- const base::Closure& task);
-
- TaskId PostTaskAndReply(base::TaskRunner* task_runner,
- const tracked_objects::Location& from_here,
- const base::Closure& task,
- const base::Closure& reply);
-
- template <typename TaskReturnType, typename ReplyArgType>
- TaskId PostTaskAndReplyWithResult(
- base::TaskRunner* task_runner,
- const tracked_objects::Location& from_here,
- const base::Callback<TaskReturnType(void)>& task,
- const base::Callback<void(ReplyArgType)>& reply) {
- TaskReturnType* result = new TaskReturnType();
- return PostTaskAndReply(
- task_runner,
- from_here,
- base::Bind(&base::internal::ReturnAsParamAdapter<TaskReturnType>,
- task,
- base::Unretained(result)),
- base::Bind(&base::internal::ReplyAdapter<TaskReturnType, ReplyArgType>,
- reply,
- base::Owned(result)));
- }
-
- // Creates a tracked TaskId and an associated IsCanceledCallback. Client can
- // later call TryCancel() with the returned TaskId, and run |is_canceled_cb|
- // from any thread to check whether the TaskId is canceled.
- //
- // The returned task ID is tracked until the last copy of
- // |is_canceled_cb| is destroyed.
- //
- // Note. This function is used to address some special cancelation requirement
- // in existing code. You SHOULD NOT need this function in new code.
- TaskId NewTrackedTaskId(IsCanceledCallback* is_canceled_cb);
-
- // After calling this function, |task| and |reply| will not run. If the
- // cancelation happens when |task| is running or has finished running, |reply|
- // will not run. If |reply| is running or has finished running, cancellation
- // is a noop.
- //
- // Note. It's OK to cancel a |task| for more than once. The later calls are
- // noops.
- void TryCancel(TaskId id);
-
- // It's OK to call this function for more than once. The later calls are
- // noops.
- void TryCancelAll();
-
- // Returns true iff there are in-flight tasks that are still being
- // tracked.
- bool HasTrackedTasks() const;
-
- private:
- void Track(TaskId id, base::CancellationFlag* flag);
- void Untrack(TaskId id);
-
- base::hash_map<TaskId, base::CancellationFlag*> task_flags_;
-
- TaskId next_id_;
- base::ThreadChecker thread_checker_;
-
- base::WeakPtrFactory<CancelableTaskTracker> weak_factory_;
-
- DISALLOW_COPY_AND_ASSIGN(CancelableTaskTracker);
-};
-
-} // namespace base
-
-#endif // BASE_TASK_CANCELABLE_TASK_TRACKER_H_
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