Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(743)

Unified Diff: base/timer/timer.h

Issue 1433373003: Use SequenceChecker to allow Timer to run in SequencedWorkerPool (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Review nits Created 5 years ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « no previous file | base/timer/timer.cc » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: base/timer/timer.h
diff --git a/base/timer/timer.h b/base/timer/timer.h
index c5bd9ced5ae277f614fc53b49b83441458ec5cdc..68a385b65da9053b6055c8f4a10fb65480482934 100644
--- a/base/timer/timer.h
+++ b/base/timer/timer.h
@@ -39,7 +39,10 @@
// other words, Reset is shorthand for calling Stop and then Start again with
// the same arguments.
//
-// NOTE: These APIs are not thread safe. Always call from the same thread.
+// These APIs are not thread safe. Always call from the same sequenced task
+// runner - thread or worker pool. By default the scheduled tasks will be run
+// on the same sequence that the APIs are called from, but this can be changed
+// prior to any tasks being scheduled using SetTaskRunner().
#ifndef BASE_TIMER_TIMER_H_
#define BASE_TIMER_TIMER_H_
@@ -55,17 +58,18 @@
#include "base/bind_helpers.h"
#include "base/callback.h"
#include "base/location.h"
+#include "base/sequence_checker.h"
#include "base/time/time.h"
namespace base {
class BaseTimerTaskInternal;
-class SingleThreadTaskRunner;
+class SequencedTaskRunner;
//-----------------------------------------------------------------------------
-// This class wraps MessageLoop::PostDelayedTask to manage delayed and repeating
-// tasks. It must be destructed on the same thread that starts tasks. There are
-// DCHECKs in place to verify this.
+// This class wraps TaskRunner::PostDelayedTask to manage delayed and
+// repeating tasks. It must be destructed on the same task runner that starts
+// tasks. There are DCHECKs in place to verify this.
//
class BASE_EXPORT Timer {
public:
@@ -89,9 +93,9 @@ class BASE_EXPORT Timer {
virtual TimeDelta GetCurrentDelay() const;
// Set the task runner on which the task should be scheduled. This method can
- // only be called before any tasks have been scheduled. The task runner must
- // run tasks on the same thread the timer is used on.
- virtual void SetTaskRunner(scoped_refptr<SingleThreadTaskRunner> task_runner);
+ // only be called before any tasks have been scheduled. |task_runner| must
+ // run tasks on the same sequence the timer is used on.
+ virtual void SetTaskRunner(scoped_refptr<SequencedTaskRunner> task_runner);
// Start the timer to run at the given |delay| from now. If the timer is
// already running, it will be replaced to call the given |user_task|.
@@ -134,10 +138,11 @@ class BASE_EXPORT Timer {
// and desired_run_time_ are reset to Now() + delay.
void PostNewScheduledTask(TimeDelta delay);
- // Returns the task runner on which the task should be scheduled. If the
- // corresponding task_runner_ field is null, the task runner for the current
- // thread is returned.
- scoped_refptr<SingleThreadTaskRunner> GetTaskRunner();
+ // Returns the task runner on which the task should be scheduled. If
+ // |destination_task_runner_| field is null, returns the SequencedTaskRunner
+ // for the
+ // current thread.
+ scoped_refptr<SequencedTaskRunner> GetTaskRunner();
// Disable scheduled_task_ and abandon it so that it no longer refers back to
// this object.
@@ -157,8 +162,8 @@ class BASE_EXPORT Timer {
BaseTimerTaskInternal* scheduled_task_;
// The task runner on which the task should be scheduled. If it is null, the
- // task runner for the current thread should be used.
- scoped_refptr<SingleThreadTaskRunner> task_runner_;
+ // task runner for the current thread is used.
+ scoped_refptr<SequencedTaskRunner> destination_task_runner_;
// Location in user code.
tracked_objects::Location posted_from_;
@@ -181,8 +186,15 @@ class BASE_EXPORT Timer {
// if the task must be run immediately.
TimeTicks desired_run_time_;
- // Thread ID of current MessageLoop for verifying single-threaded usage.
- int thread_id_;
+ // Calls to the timer are not thread safe, so a checker is used detect
+ // incorrect usage in debug builds. Note that this verifies the timer API
+ // calls; the tasks may be scheduled by the timer on a different sequence if
+ // SetTaskRunner() is used.
+ SequenceChecker origin_sequence_checker_;
+
+ // Once the timer has been scheduled, destination_task_runner_ may not be
+ // changed.
+ bool was_scheduled_;
// Repeating timers automatically post the task again before calling the task
// callback.
@@ -242,8 +254,7 @@ class RepeatingTimer : public BaseTimerMethodPointer {
//-----------------------------------------------------------------------------
// A Delay timer is like The Button from Lost. Once started, you have to keep
-// calling Reset otherwise it will call the given method in the MessageLoop
-// thread.
+// calling Reset otherwise it will call the given method on the task runner.
//
// Once created, it is inactive until Reset is called. Once |delay| seconds have
// passed since the last call to Reset, the callback is made. Once the callback
« no previous file with comments | « no previous file | base/timer/timer.cc » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698