ipc/chromium/src/base/lock.h@6474c204b198
ipc/chromium/src/base/lock.h
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.
1 // Copyright (c) 2006-2009 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_H_
6 #define BASE_LOCK_H_
8 #include "base/lock_impl.h"
10 // A convenient wrapper for an OS specific critical section.
12 class Lock {
13 public:
14 Lock() : lock_() {}
15 ~Lock() {}
16 void Acquire() { lock_.Lock(); }
17 void Release() { lock_.Unlock(); }
18 // If the lock is not held, take it and return true. If the lock is already
19 // held by another thread, immediately return false.
20 bool Try() { return lock_.Try(); }
22 // In debug builds this method checks that the lock has been acquired by the
23 // calling thread. If the lock has not been acquired, then the method
24 // will DCHECK(). In non-debug builds, the LockImpl's implementation of
25 // AssertAcquired() is an empty inline method.
26 void AssertAcquired() const { return lock_.AssertAcquired(); }
28 // Return the underlying lock implementation.
29 // TODO(awalker): refactor lock and condition variables so that this is
30 // unnecessary.
31 LockImpl* lock_impl() { return &lock_; }
33 private:
34 LockImpl lock_; // Platform specific underlying lock implementation.
36 DISALLOW_COPY_AND_ASSIGN(Lock);
37 };
39 // A helper class that acquires the given Lock while the AutoLock is in scope.
40 class AutoLock {
41 public:
42 explicit AutoLock(Lock& lock) : lock_(lock) {
43 lock_.Acquire();
44 }
46 ~AutoLock() {
47 lock_.AssertAcquired();
48 lock_.Release();
49 }
51 private:
52 Lock& lock_;
53 DISALLOW_COPY_AND_ASSIGN(AutoLock);
54 };
56 // AutoUnlock is a helper that will Release() the |lock| argument in the
57 // constructor, and re-Acquire() it in the destructor.
58 class AutoUnlock {
59 public:
60 explicit AutoUnlock(Lock& lock) : lock_(lock) {
61 // We require our caller to have the lock.
62 lock_.AssertAcquired();
63 lock_.Release();
64 }
66 ~AutoUnlock() {
67 lock_.Acquire();
68 }
70 private:
71 Lock& lock_;
72 DISALLOW_COPY_AND_ASSIGN(AutoUnlock);
73 };
75 #endif // BASE_LOCK_H_
