From 5c0b44355d76bc88064b1363fe1591668b536da5 Mon Sep 17 00:00:00 2001 From: "tommycli@chromium.org" Date: Fri, 26 Jul 2013 14:23:56 +0000 Subject: base: Re-apply WeakPtr support for SequencedWorkerPools, fixing deadlock This reverts the revert found here: https://codereview.chromium.org/19882002 It also fixes the deadlock that caused the revert, reported here: http://crbug.com/261448 Patchset 1 is simply what was originally committed (and reverted). Subsequent patchsets show the fix of the deadlock problem. BUG=165590 TBR=darin Review URL: https://chromiumcodereview.appspot.com/20163004 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@213906 0039d316-1c4b-4281-b951-d872f2087c98 --- base/sequence_checker_impl.h | 42 ++++++++++++++++++------------------------ 1 file changed, 18 insertions(+), 24 deletions(-) (limited to 'base/sequence_checker_impl.h') diff --git a/base/sequence_checker_impl.h b/base/sequence_checker_impl.h index ccd1198..741aafe 100644 --- a/base/sequence_checker_impl.h +++ b/base/sequence_checker_impl.h @@ -7,48 +7,42 @@ #include "base/base_export.h" #include "base/basictypes.h" -#include "base/memory/ref_counted.h" #include "base/synchronization/lock.h" +#include "base/threading/sequenced_worker_pool.h" #include "base/threading/thread_checker_impl.h" namespace base { -class SequencedTaskRunner; - // SequenceCheckerImpl is used to help verify that some methods of a // class are called in sequence -- that is, called from the same // SequencedTaskRunner. It is a generalization of ThreadChecker; in -// particular, it behaves exactly like ThreadChecker if its passed a -// NULL SequencedTaskRunner. +// particular, it behaves exactly like ThreadChecker if constructed +// on a thread that is not part of a SequencedWorkerPool. class BASE_EXPORT SequenceCheckerImpl { public: - // |sequenced_task_runner| can be NULL. In that case, this object - // behaves exactly like a ThreadChecker bound to the current thread, - // i.e. CalledOnValidSequence() behaves like CalledOnValidThread(). - explicit SequenceCheckerImpl( - const scoped_refptr& sequenced_task_runner); + SequenceCheckerImpl(); ~SequenceCheckerImpl(); - // Returns whether the we are being called on the underyling - // SequencedTaskRunner. If we're not bound to a - // |sequenced_task_runner|, returns whether we are being called on - // the underlying ThreadChecker's thread. - bool CalledOnValidSequence() const; + // Returns whether the we are being called on the same sequence token + // as previous calls. If there is no associated sequence, then returns + // whether we are being called on the underlying ThreadChecker's thread. + bool CalledOnValidSequencedThread() const; - // Changes the underyling SequencedTaskRunner. - // |sequenced_task_runner| can be NULL. In that case, this object - // behaves exactly like a ThreadChecker that has been detached from - // its thread, i.e. we will be bound to the thread on which we next - // call CalledOnValidSequence(). - void ChangeSequence( - const scoped_refptr& sequenced_task_runner); + // Unbinds the checker from the currently associated sequence. The + // checker will be re-bound on the next call to CalledOnValidSequence(). + void DetachFromSequence(); private: + void EnsureSequenceTokenAssigned() const; + // Guards all variables below. mutable Lock lock_; - scoped_refptr sequenced_task_runner_; - // Used if |sequenced_task_runner_| is NULL. + + // Used if |sequence_token_| is not valid. ThreadCheckerImpl thread_checker_; + mutable bool sequence_token_assigned_; + + mutable SequencedWorkerPool::SequenceToken sequence_token_; DISALLOW_COPY_AND_ASSIGN(SequenceCheckerImpl); }; -- cgit v1.1