proxy_lock.cc revision 2a99a7e74a7f215066514fe81d2bfa6639d9eddd 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "ppapi/shared_impl/proxy_lock.h"
6
7#include "base/lazy_instance.h"
8#include "base/synchronization/lock.h"
9#include "base/threading/thread_local.h"
10#include "ppapi/shared_impl/ppapi_globals.h"
11
12namespace ppapi {
13
14// Simple single-thread deadlock detector for the proxy lock.
15// |true| when the current thread has the lock.
16base::LazyInstance<base::ThreadLocalBoolean>::Leaky
17    g_proxy_locked_on_thread = LAZY_INSTANCE_INITIALIZER;
18
19// static
20void ProxyLock::Acquire() {
21  base::Lock* lock(PpapiGlobals::Get()->GetProxyLock());
22  if (lock) {
23    // This thread does not already hold the lock.
24    const bool deadlock = g_proxy_locked_on_thread.Get().Get();
25    CHECK(!deadlock);
26
27    lock->Acquire();
28    g_proxy_locked_on_thread.Get().Set(true);
29  }
30}
31
32// static
33void ProxyLock::Release() {
34  base::Lock* lock(PpapiGlobals::Get()->GetProxyLock());
35  if (lock) {
36    // This thread currently holds the lock.
37    const bool locked = g_proxy_locked_on_thread.Get().Get();
38    CHECK(locked);
39
40    g_proxy_locked_on_thread.Get().Set(false);
41    lock->Release();
42  }
43}
44
45// static
46void ProxyLock::AssertAcquired() {
47  base::Lock* lock(PpapiGlobals::Get()->GetProxyLock());
48  if (lock) {
49    // This thread currently holds the lock.
50    const bool locked = g_proxy_locked_on_thread.Get().Get();
51    CHECK(locked);
52
53    lock->AssertAcquired();
54  }
55}
56
57void CallWhileUnlocked(const base::Closure& closure) {
58  ProxyAutoUnlock lock;
59  closure.Run();
60}
61
62void CallWhileLocked(const base::Closure& closure) {
63  ProxyAutoLock lock;
64  closure.Run();
65}
66
67}  // namespace ppapi
68