ralphl@chromium.org
5a98eadfaa
Also changed Lock::AssertAcquired to be const function (it already was const, in practice, just not declared that way). Review URL: http://codereview.chromium.org/42402 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@12157 0039d316-1c4b-4281-b951-d872f2087c98
78 linhas
2.2 KiB
C++
78 linhas
2.2 KiB
C++
// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_LOCK_IMPL_H_
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#define BASE_LOCK_IMPL_H_
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#include "build/build_config.h"
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#if defined(OS_WIN)
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#include <windows.h>
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#elif defined(OS_POSIX)
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#include <pthread.h>
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#endif
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#include "base/basictypes.h"
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#include "base/platform_thread.h"
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// This class implements the underlying platform-specific spin-lock mechanism
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// used for the Lock class. Most users should not use LockImpl directly, but
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// should instead use Lock.
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class LockImpl {
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public:
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#if defined(OS_WIN)
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typedef CRITICAL_SECTION OSLockType;
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#elif defined(OS_POSIX)
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typedef pthread_mutex_t OSLockType;
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#endif
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LockImpl();
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~LockImpl();
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// If the lock is not held, take it and return true. If the lock is already
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// held by something else, immediately return false.
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bool Try();
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// Take the lock, blocking until it is available if necessary.
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void Lock();
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// Release the lock. This must only be called by the lock's holder: after
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// a successful call to Try, or a call to Lock.
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void Unlock();
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// Debug-only method that will DCHECK() if the lock is not acquired by the
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// current thread. In non-debug builds, no check is performed.
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// Because linux and mac condition variables modify the underlyning lock
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// through the os_lock() method, runtime assertions can not be done on those
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// builds.
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#if defined(NDEBUG) || !defined(OS_WIN)
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void AssertAcquired() const {}
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#else
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void AssertAcquired() const;
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#endif
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// Return the native underlying lock. Not supported for Windows builds.
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// TODO(awalker): refactor lock and condition variables so that this is
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// unnecessary.
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#if !defined(OS_WIN)
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OSLockType* os_lock() { return &os_lock_; }
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#endif
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private:
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OSLockType os_lock_;
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#if !defined(NDEBUG) && defined(OS_WIN)
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// All private data is implicitly protected by lock_.
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// Be VERY careful to only access members under that lock.
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PlatformThreadId owning_thread_id_;
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int32 recursion_count_shadow_;
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bool recursion_used_; // Allow debugging to continued after a DCHECK().
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#endif // NDEBUG
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DISALLOW_COPY_AND_ASSIGN(LockImpl);
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};
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#endif // BASE_LOCK_IMPL_H_
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