Expose SingleThreadTaskRunnerThreadMode in post_task.h

base/task_scheduler/post_task.h

 // Copyright 2016 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_SCHEDULER_POST_TASK_H_
 #define BASE_TASK_SCHEDULER_POST_TASK_H_
 
 #include <utility>
 
 #include "base/base_export.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/location.h"
 #include "base/memory/ref_counted.h"
 #include "base/post_task_and_reply_with_result_internal.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
 #include "base/task_runner.h"
+#include "base/task_scheduler/single_thread_task_runner_thread_mode.h"
 #include "base/task_scheduler/task_traits.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 
 namespace base {
 
 // This is the preferred interface to post tasks to the TaskScheduler.
 //
 // To post a simple one-off task with default traits:
 //     PostTask(FROM_HERE, Bind(...));
@@ skipping 154 matching lines @@
 // using |traits|. Tasks may run in any order and in parallel.
 BASE_EXPORT scoped_refptr<TaskRunner> CreateTaskRunnerWithTraits(
     const TaskTraits& traits);
 
 // Returns a SequencedTaskRunner whose PostTask invocations result in scheduling
 // tasks using |traits|. Tasks run one at a time in posting order.
 BASE_EXPORT scoped_refptr<SequencedTaskRunner>
 CreateSequencedTaskRunnerWithTraits(const TaskTraits& traits);
 
 // Returns a SingleThreadTaskRunner whose PostTask invocations result in
-// scheduling tasks using |traits|. Tasks run on a single thread in posting
-// order.
+// scheduling tasks using |traits| on a thread determined by |thread_mode|. See
+// base/task_scheduler/single_thread_task_runner_thread_mode.h for |thread_mode|

[fdoray, 2017/05/15 19:20:06]

"See base/task_scheduler/single_thread_task_runner_thread_mode.h"
Obvious to look at the definition of an enum for more details?

[robliao, 2017/05/15 19:22:44]

I wanted to avoid duplicating those details here, so a reference seemed to make
more sense.

+// details. Tasks run on a single thread in posting order.
 //
 // If all you need is to make sure that tasks don't run concurrently (e.g.
 // because they access a data structure which is not thread-safe), use
 // CreateSequencedTaskRunnerWithTraits(). Only use this if you rely on a thread-
 // affine API (it might be safer to assume thread-affinity when dealing with
 // under-documented third-party APIs, e.g. other OS') or share data across tasks
 // using thread-local storage.
 BASE_EXPORT scoped_refptr<SingleThreadTaskRunner>
-CreateSingleThreadTaskRunnerWithTraits(const TaskTraits& traits);
+CreateSingleThreadTaskRunnerWithTraits(
+    const TaskTraits& traits,
+    SingleThreadTaskRunnerThreadMode thread_mode =
+        SingleThreadTaskRunnerThreadMode::SHARED);
 
 #if defined(OS_WIN)
 // Returns a SingleThreadTaskRunner whose PostTask invocations result in
-// scheduling tasks using |traits| in a COM Single-Threaded Apartment. Tasks run
-// in the same Single-Threaded Apartment in posting order for the returned
-// SingleThreadTaskRunner. There is not necessarily a one-to-one correspondence
-// between SingleThreadTaskRunners and Single-Threaded Apartments. The
-// implementation is free to share apartments or create new apartments as
-// necessary. In either case, care should be taken to make sure COM pointers are
-// not smuggled across apartments.
+// scheduling tasks using |traits| in a COM Single-Threaded Apartment on a
+// thread determined by |thread_mode|. See
+// base/task_scheduler/single_thread_task_runner_thread_mode.h for |thread_mode|

[fdoray, 2017/05/15 19:20:06]

ditto

+// details. Tasks run in the same Single-Threaded Apartment in posting order for
+// the returned SingleThreadTaskRunner. There is not necessarily a one-to-one
+// correspondence between SingleThreadTaskRunners and Single-Threaded
+// Apartments. The implementation is free to share apartments or create new
+// apartments as necessary. In either case, care should be taken to make sure
+// COM pointers are not smuggled across apartments.
 BASE_EXPORT scoped_refptr<SingleThreadTaskRunner>
-CreateCOMSTATaskRunnerWithTraits(const TaskTraits& traits);
+CreateCOMSTATaskRunnerWithTraits(const TaskTraits& traits,
+                                 SingleThreadTaskRunnerThreadMode thread_mode =
+                                     SingleThreadTaskRunnerThreadMode::SHARED);

[gab, 2017/05/15 19:54:29]

remove default in TaskScheduler (it's not intended to be called directly)

[robliao, 2017/05/15 20:58:27]

Done.

 #endif  // defined(OS_WIN)
 
 }  // namespace base
 
 #endif  // BASE_TASK_SCHEDULER_POST_TASK_H_