ipc/chromium/src/base/thread_collision_warner.cc@6474c204b198 (annotated)
ipc/chromium/src/base/thread_collision_warner.cc
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. |
| michael@0 | 2 | // Use of this source code is governed by a BSD-style license that can be |
| michael@0 | 3 | // found in the LICENSE file. |
| michael@0 | 4 | |
| michael@0 | 5 | #include "base/thread_collision_warner.h" |
| michael@0 | 6 | |
| michael@0 | 7 | #include "base/logging.h" |
| michael@0 | 8 | #include "base/platform_thread.h" |
| michael@0 | 9 | |
| michael@0 | 10 | namespace base { |
| michael@0 | 11 | |
| michael@0 | 12 | void DCheckAsserter::warn() { |
| michael@0 | 13 | NOTREACHED() << "Thread Collision"; |
| michael@0 | 14 | } |
| michael@0 | 15 | |
| michael@0 | 16 | static subtle::Atomic32 CurrentThread() { |
| michael@0 | 17 | const PlatformThreadId current_thread_id = PlatformThread::CurrentId(); |
| michael@0 | 18 | // We need to get the thread id into an atomic data type. This might be a |
| michael@0 | 19 | // truncating conversion, but any loss-of-information just increases the |
| michael@0 | 20 | // chance of a fault negative, not a false positive. |
| michael@0 | 21 | const subtle::Atomic32 atomic_thread_id = |
| michael@0 | 22 | static_cast<subtle::Atomic32>(current_thread_id); |
| michael@0 | 23 | |
| michael@0 | 24 | return atomic_thread_id; |
| michael@0 | 25 | } |
| michael@0 | 26 | |
| michael@0 | 27 | void ThreadCollisionWarner::EnterSelf() { |
| michael@0 | 28 | // If the active thread is 0 then I'll write the current thread ID |
| michael@0 | 29 | // if two or more threads arrive here only one will succeed to |
| michael@0 | 30 | // write on valid_thread_id_ the current thread ID. |
| michael@0 | 31 | subtle::Atomic32 current_thread_id = CurrentThread(); |
| michael@0 | 32 | |
| michael@0 | 33 | int previous_value = subtle::NoBarrier_CompareAndSwap(&valid_thread_id_, |
| michael@0 | 34 | 0, |
| michael@0 | 35 | current_thread_id); |
| michael@0 | 36 | if (previous_value != 0 && previous_value != current_thread_id) { |
| michael@0 | 37 | // gotcha! a thread is trying to use the same class and that is |
| michael@0 | 38 | // not current thread. |
| michael@0 | 39 | asserter_->warn(); |
| michael@0 | 40 | } |
| michael@0 | 41 | |
| michael@0 | 42 | subtle::NoBarrier_AtomicIncrement(&counter_, 1); |
| michael@0 | 43 | } |
| michael@0 | 44 | |
| michael@0 | 45 | void ThreadCollisionWarner::Enter() { |
| michael@0 | 46 | subtle::Atomic32 current_thread_id = CurrentThread(); |
| michael@0 | 47 | |
| michael@0 | 48 | if (subtle::NoBarrier_CompareAndSwap(&valid_thread_id_, |
| michael@0 | 49 | 0, |
| michael@0 | 50 | current_thread_id) != 0) { |
| michael@0 | 51 | // gotcha! another thread is trying to use the same class. |
| michael@0 | 52 | asserter_->warn(); |
| michael@0 | 53 | } |
| michael@0 | 54 | |
| michael@0 | 55 | subtle::NoBarrier_AtomicIncrement(&counter_, 1); |
| michael@0 | 56 | } |
| michael@0 | 57 | |
| michael@0 | 58 | void ThreadCollisionWarner::Leave() { |
| michael@0 | 59 | if (subtle::Barrier_AtomicIncrement(&counter_, -1) == 0) { |
| michael@0 | 60 | subtle::NoBarrier_Store(&valid_thread_id_, 0); |
| michael@0 | 61 | } |
| michael@0 | 62 | } |
| michael@0 | 63 | |
| michael@0 | 64 | } // namespace base |
