ppapi/shared_impl/proxy_lock.cc

   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
  12 namespace ppapi {
  13
  14 // Simple single-thread deadlock detector for the proxy lock.
  15 // |true| when the current thread has the lock.
  16 base::LazyInstance<base::ThreadLocalBoolean>::Leaky
  17     g_proxy_locked_on_thread = LAZY_INSTANCE_INITIALIZER;
  18
  19 // static
  20 void 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
  33 void 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
  46 void 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
  57 void CallWhileUnlocked(const base::Closure& closure) {
  58   ProxyAutoUnlock lock;
  59   closure.Run();
  60 }
  61
  62 }  // namespace ppapi