The Tor Browser: ipc/chromium/src/base/lock

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 // Copyright (c) 2006-2008 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.

     5 #ifndef BASE_LOCK_IMPL_H_

     6 #define BASE_LOCK_IMPL_H_

     8 #include "build/build_config.h"

    10 #if defined(OS_WIN)

    11 #include <windows.h>

    12 #elif defined(OS_POSIX)

    13 #include <pthread.h>

    14 #endif

    16 #include "base/basictypes.h"

    17 #include "base/platform_thread.h"

    19 // This class implements the underlying platform-specific spin-lock mechanism

    20 // used for the Lock class.  Most users should not use LockImpl directly, but

    21 // should instead use Lock.

    22 class LockImpl {

    23  public:

    24 #if defined(OS_WIN)

    25   typedef CRITICAL_SECTION OSLockType;

    26 #elif defined(OS_POSIX)

    27   typedef pthread_mutex_t OSLockType;

    28 #endif

    30   LockImpl();

    31   ~LockImpl();

    33   // If the lock is not held, take it and return true.  If the lock is already

    34   // held by something else, immediately return false.

    35   bool Try();

    37   // Take the lock, blocking until it is available if necessary.

    38   void Lock();

    40   // Release the lock.  This must only be called by the lock's holder: after

    41   // a successful call to Try, or a call to Lock.

    42   void Unlock();

    44   // Debug-only method that will DCHECK() if the lock is not acquired by the

    45   // current thread.  In non-debug builds, no check is performed.

    46   // Because linux and mac condition variables modify the underlyning lock

    47   // through the os_lock() method, runtime assertions can not be done on those

    48   // builds.

    49 #if defined(NDEBUG) || !defined(OS_WIN)

    50   void AssertAcquired() const {}

    51 #else

    52   void AssertAcquired() const;

    53 #endif

    55   // Return the native underlying lock.  Not supported for Windows builds.

    56   // TODO(awalker): refactor lock and condition variables so that this is

    57   // unnecessary.

    58 #if !defined(OS_WIN)

    59   OSLockType* os_lock() { return &os_lock_; }

    60 #endif

    62  private:

    63   OSLockType os_lock_;

    65 #if !defined(NDEBUG) && defined(OS_WIN)

    66   // All private data is implicitly protected by lock_.

    67   // Be VERY careful to only access members under that lock.

    68   PlatformThreadId owning_thread_id_;

    69   int32_t recursion_count_shadow_;

    70   bool recursion_used_;      // Allow debugging to continued after a DCHECK().

    71 #endif  // NDEBUG

    73   DISALLOW_COPY_AND_ASSIGN(LockImpl);

    74 };

    77 #endif  // BASE_LOCK_IMPL_H_

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