diff options
Diffstat (limited to 'base/lock.h')
-rw-r--r-- | base/lock.h | 68 |
1 files changed, 10 insertions, 58 deletions
diff --git a/base/lock.h b/base/lock.h index 64b8f74..31ad9a0 100644 --- a/base/lock.h +++ b/base/lock.h @@ -7,78 +7,30 @@ #include "base/lock_impl.h" -// A convenient wrapper for an OS specific critical section. The only real -// intelligence in this class is in debug mode for the support for the -// AssertAcquired() method. +// A convenient wrapper for an OS specific critical section. class Lock { public: -#if defined(NDEBUG) // Optimized wrapper implementation Lock() : lock_() {} ~Lock() {} void Acquire() { lock_.Lock(); } void Release() { lock_.Unlock(); } - // If the lock is not held, take it and return true. If the lock is already // held by another thread, immediately return false. bool Try() { return lock_.Try(); } - // Null implementation if not debug. - void AssertAcquired() const {} -#else - Lock(); - ~Lock() {} - - // NOTE: Although windows critical sections support recursive locks, we do not - // allow this, and we will commonly fire a DCHECK() if a thread attempts to - // acquire the lock a second time (while already holding it). - void Acquire() { - lock_.Lock(); - CheckUnheldAndMark(); - } - void Release() { - CheckHeldAndUnmark(); - lock_.Unlock(); - } + // In debug builds this method checks that the lock has been acquired by the + // calling thread. If the lock has not been acquired, then the method + // will DCHECK(). In non-debug builds, the LockImpl's implementation of + // AssertAcquired() is an empty inline method. + void AssertAcquired() const { return lock_.AssertAcquired(); } - bool Try() { - bool rv = lock_.Try(); - if (rv) { - CheckUnheldAndMark(); - } - return rv; - } - - void AssertAcquired() const; -#endif // NDEBUG - -#if defined(OS_POSIX) - // The posix implementation of ConditionVariable needs to be able - // to see our lock and tweak our debugging counters, as it releases - // and acquires locks inside of pthread_cond_{timed,}wait. - // Windows doesn't need to do this as it calls the Lock::* methods. - friend class ConditionVariable; -#endif + // Return the underlying lock implementation. + // TODO(awalker): refactor lock and condition variables so that this is + // unnecessary. + LockImpl* lock_impl() { return &lock_; } private: -#if !defined(NDEBUG) - // Members and routines taking care of locks assertions. - // Note that this checks for recursive locks and allows them - // if the variable is set. This is allowed by the underlying implementation - // on windows but not on Posix, so we're doing unneeded checks on Posix. - // It's worth it to share the code. - void CheckHeldAndUnmark(); - void CheckUnheldAndMark(); - - // All private data is implicitly protected by lock_. - // Be VERY careful to only access members under that lock. - - // Determines validity of owning_thread_id_. Needed as we don't have - // a null owning_thread_id_ value. - bool owned_by_thread_; - PlatformThreadId owning_thread_id_; -#endif // NDEBUG - LockImpl lock_; // Platform specific underlying lock implementation. DISALLOW_COPY_AND_ASSIGN(Lock); |