version 1.3, 2006/08/21 08:48:20
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version 1.12, 2008/09/09 17:38:27
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#ifdef PEGASUS_USE_POSIX_RWLOCK | #ifdef PEGASUS_USE_POSIX_RWLOCK |
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ReadWriteSem::ReadWriteSem():_readers(0), _writers(0) |
ReadWriteSem::ReadWriteSem() |
{ | { |
pthread_rwlock_init(&_rwlock.rwlock, NULL); | pthread_rwlock_init(&_rwlock.rwlock, NULL); |
Threads::clear(_rwlock.owner); |
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} | } |
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ReadWriteSem::~ReadWriteSem() | ReadWriteSem::~ReadWriteSem() |
{ | { |
int r=0; | int r=0; |
while (r=pthread_rwlock_destroy(&_rwlock.rwlock) == EBUSY || (r == -1 && errno == EBUSY)) |
while ((r = pthread_rwlock_destroy(&_rwlock.rwlock)) == EBUSY || |
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(r == -1 && errno == EBUSY)) |
{ | { |
Threads::yield(); | Threads::yield(); |
} | } |
} | } |
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void ReadWriteSem::wait(Uint32 mode, ThreadType caller) |
void ReadWriteSem::waitRead() |
{ | { |
int errorcode; |
if (pthread_rwlock_rdlock(&_rwlock.rwlock) != 0) |
if (mode == PEG_SEM_READ) |
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{ | { |
if (0 == (errorcode = pthread_rwlock_rdlock(&_rwlock.rwlock))) |
throw WaitFailed(Threads::self()); |
{ |
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_readers++; |
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return; |
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} |
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} |
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else if (mode == PEG_SEM_WRITE) |
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{ |
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if (0 == (errorcode = pthread_rwlock_wrlock(&_rwlock.rwlock))) |
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{ |
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_rwlock.owner = caller; |
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_writers++; |
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return; |
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} | } |
} | } |
else |
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throw(Permission(Threads::self())); |
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if (errorcode == EDEADLK) |
void ReadWriteSem::waitWrite() |
throw(Deadlock(_rwlock.owner)); |
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else |
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throw(WaitFailed(Threads::self())); |
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} |
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void ReadWriteSem::try_wait(Uint32 mode, ThreadType caller) |
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{ |
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int errorcode = 0; |
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if (mode == PEG_SEM_READ) |
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{ | { |
if (0 == (errorcode = pthread_rwlock_tryrdlock(&_rwlock.rwlock))) |
if (pthread_rwlock_wrlock(&_rwlock.rwlock) != 0) |
{ | { |
_readers++; |
throw WaitFailed(Threads::self()); |
return; |
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} |
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} | } |
else if (mode == PEG_SEM_WRITE) |
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{ |
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if (0 == (errorcode = pthread_rwlock_trywrlock(&_rwlock.rwlock))) |
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{ |
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_writers++; |
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_rwlock.owner = caller; |
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return; |
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} | } |
} |
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else |
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throw(Permission(Threads::self())); |
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if (errorcode == -1) |
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errorcode = errno; |
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if (errorcode == EBUSY) |
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throw(AlreadyLocked(_rwlock.owner)); |
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else if (errorcode == EDEADLK) |
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throw(Deadlock(_rwlock.owner)); |
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else |
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throw(WaitFailed(Threads::self())); |
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} |
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// timedrdlock and timedwrlock are not supported on HPUX |
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// mdday Sun Aug 5 14:21:00 2001 |
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void ReadWriteSem::timed_wait(Uint32 mode, |
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ThreadType caller, int milliseconds) |
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{ |
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int errorcode = 0, timeout = 0; |
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struct timeval now, finish, remaining; |
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Uint32 usec; |
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gettimeofday(&finish, NULL); |
void ReadWriteSem::unlockRead() |
finish.tv_sec += (milliseconds / 1000); |
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milliseconds %= 1000; |
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usec = finish.tv_usec + (milliseconds * 1000); |
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finish.tv_sec += (usec / 1000000); |
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finish.tv_usec = usec % 1000000; |
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if (mode == PEG_SEM_READ) |
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{ |
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do |
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{ | { |
errorcode = pthread_rwlock_tryrdlock(&_rwlock.rwlock); |
int rc = pthread_rwlock_unlock(&_rwlock.rwlock); |
if (errorcode == -1) |
// All documented error codes represent coding errors. |
errorcode = errno; |
PEGASUS_ASSERT(rc == 0); |
gettimeofday(&now, NULL); |
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} |
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while (errorcode == EBUSY && |
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(0 == (timeout = Time::subtract(&remaining, &finish, &now)))); |
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if (0 == errorcode) |
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{ |
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_readers++; |
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return; |
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} |
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} | } |
else if (mode == PEG_SEM_WRITE) |
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{ |
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do |
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{ |
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errorcode = pthread_rwlock_trywrlock(&_rwlock.rwlock); |
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if (errorcode == -1) |
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errorcode = errno; |
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gettimeofday(&now, NULL); |
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} |
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while (errorcode == EBUSY && |
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(0 == (timeout = Time::subtract(&remaining, &finish, &now)))); |
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if (0 == errorcode) |
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{ |
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_writers++; |
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_rwlock.owner = caller; |
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return; |
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} |
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} |
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else |
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throw(Permission(Threads::self())); |
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if (timeout != 0) |
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throw(TimeOut(_rwlock.owner)); |
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else if (errorcode == EDEADLK) |
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throw(Deadlock(_rwlock.owner)); |
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else |
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throw(WaitFailed(Threads::self())); |
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} |
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void ReadWriteSem::unlock(Uint32 mode, ThreadType caller) |
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{ |
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ThreadType owner; |
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if (mode == PEG_SEM_WRITE) |
void ReadWriteSem::unlockWrite() |
{ | { |
owner = _rwlock.owner; |
int rc = pthread_rwlock_unlock(&_rwlock.rwlock); |
Threads::clear(_rwlock.owner); |
// All documented error codes represent coding errors. |
} |
PEGASUS_ASSERT(rc == 0); |
if (0 != pthread_rwlock_unlock(&_rwlock.rwlock)) |
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{ |
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_rwlock.owner = owner; |
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throw(Permission(Threads::self())); |
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} |
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if (mode == PEG_SEM_READ && _readers.get() != 0) |
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_readers--; |
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else if (_writers.get() != 0) |
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_writers--; |
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} |
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int ReadWriteSem::read_count() const |
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{ |
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return (_readers.get()); |
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} |
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int ReadWriteSem::write_count() const |
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{ |
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return (_writers.get()); |
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} | } |
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#endif /* PEGASUS_USE_POSIX_RWLOCK */ | #endif /* PEGASUS_USE_POSIX_RWLOCK */ |
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// 2) I do not hold the write lock | // 2) I do not hold the write lock |
// 3) I am not using a reader slot | // 3) I am not using a reader slot |
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#if 0 |
ReadWriteSem::ReadWriteSem() : _rwlock() |
void extricate_read_write(void *parm) |
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{ |
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ReadWriteSem *rws = (ReadWriteSem *) parm; |
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ThreadType myself = Threads::self(); |
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if (Threads::equal(rws->_rwlock._wlock.get_owner(), myself)) |
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rws->_rwlock._wlock.unlock(); |
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else if (rws->_readers.get() > 0) |
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rws->_rwlock._rlock.signal(); |
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if (Threads::equal(rws->_rwlock._internal_lock.get_owner(), myself)) |
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rws->_rwlock._internal_lock.unlock(); |
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} |
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#endif |
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ReadWriteSem::ReadWriteSem():_readers(0), _writers(0), _rwlock() |
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{ | { |
} | } |
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{ | { |
_rwlock._internal_lock.lock(); | _rwlock._internal_lock.lock(); |
} | } |
catch(Deadlock &) |
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{ |
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// no problem - we own the lock, which is what we want |
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} |
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catch(IPCException &) | catch(IPCException &) |
{ | { |
PEGASUS_ASSERT(0); | PEGASUS_ASSERT(0); |
} | } |
while (_readers.get() > 0 || _writers.get() > 0) |
while (_rwlock._readers.get() > 0 || _rwlock._writers.get() > 0) |
{ | { |
Threads::yield(); | Threads::yield(); |
} | } |
_rwlock._internal_lock.unlock(); | _rwlock._internal_lock.unlock(); |
} | } |
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void ReadWriteSem::waitRead() |
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//----------------------------------------------------------------- |
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// if milliseconds == -1, wait indefinately |
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// if milliseconds == 0, fast wait |
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//----------------------------------------------------------------- |
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void ReadWriteSem::timed_wait(Uint32 mode, ThreadType caller, |
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int milliseconds) |
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{ |
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//----------------------------------------------------------------- |
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// Lock this object to maintain integrity while we decide |
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// exactly what to do next. |
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//----------------------------------------------------------------- |
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// AutoPtr<IPCException> caught; |
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// IPCException caught((ThreadType)0); |
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// WaitFailed caughtWaitFailed((ThreadType)0); |
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// TimeOut caughtTimeOut((ThreadType)0); |
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// TooManyReaders caughtTooManyReaders((ThreadType)0); |
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ThreadType zero; |
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IPCException caught(zero); |
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WaitFailed caughtWaitFailed(zero); |
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TimeOut caughtTimeOut(zero); |
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TooManyReaders caughtTooManyReaders(zero); |
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// cleanup stack frame |
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{ |
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// Threads::cleanup_push(extricate_read_write, this); |
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try |
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{ |
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if (milliseconds == 0) |
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_rwlock._internal_lock.try_lock(); |
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else if (milliseconds == -1) |
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_rwlock._internal_lock.lock(); |
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else |
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_rwlock._internal_lock.timed_lock(milliseconds); |
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} |
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catch(const IPCException & e) |
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{ |
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caught = e; |
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goto throw_from_here; |
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} |
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if (mode == PEG_SEM_WRITE) |
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{ | { |
//----------------------------------------------------------------- |
// Lock the internal mutex to ensure only one waiter is processed at a time. |
// Write Lock Step 1: lock the object and allow all the readers to exit |
AutoMutex lock(_rwlock._internal_lock); |
//----------------------------------------------------------------- |
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if (milliseconds == 0) // fast wait |
// Wait for the existing writer (if any) to clear. |
{ |
while (_rwlock._writers.get() > 0) |
if (_readers.get() > 0) |
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{ |
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_rwlock._internal_lock.unlock(); |
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// caught.reset(new WaitFailed(Threads::self())); |
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caughtWaitFailed = WaitFailed(Threads::self()); |
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goto throw_from_here; |
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} |
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} |
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else if (milliseconds == -1) // infinite wait |
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{ |
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while (_readers.get() > 0) |
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Threads::yield(); |
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} |
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else // timed wait |
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{ |
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struct timeval start, now; |
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Time::gettimeofday(&start); |
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start.tv_usec += (1000 * milliseconds); |
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while (_readers.get() > 0) |
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{ |
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Time::gettimeofday(&now); |
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if ((now.tv_usec > start.tv_usec) || |
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now.tv_sec > start.tv_sec) |
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{ | { |
_rwlock._internal_lock.unlock(); |
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// caught.reset(new TimeOut(Threads::self())); |
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caughtTimeOut = TimeOut(Threads::self()); |
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goto throw_from_here; |
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} |
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Threads::yield(); | Threads::yield(); |
} | } |
} |
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//----------------------------------------------------------------- |
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// Write Lock Step 2: Obtain the Write Mutex |
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// Although there are no readers, there may be a writer |
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//----------------------------------------------------------------- |
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if (milliseconds == 0) // fast wait |
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{ |
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try |
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{ |
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_rwlock._wlock.try_lock(); |
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} |
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catch(IPCException & e) |
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{ |
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_rwlock._internal_lock.unlock(); |
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caught = e; |
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goto throw_from_here; |
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} |
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} |
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else if (milliseconds == -1) // infinite wait |
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{ |
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try |
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{ |
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_rwlock._wlock.lock(); |
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} |
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catch(const IPCException & e) |
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{ |
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_rwlock._internal_lock.unlock(); |
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caught = e; |
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goto throw_from_here; |
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} |
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} |
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else // timed wait |
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{ |
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try |
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{ |
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_rwlock._wlock.timed_lock(milliseconds); |
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} |
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catch(const IPCException & e) |
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{ |
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_rwlock._internal_lock.unlock(); |
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caught = e; |
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goto throw_from_here; |
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} |
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} |
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//----------------------------------------------------------------- |
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// Write Lock Step 3: set the writer count to one, unlock the object |
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// There are no readers and we are the only writer ! |
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//----------------------------------------------------------------- |
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_writers = 1; |
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// set the owner |
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_rwlock._owner = Threads::self(); |
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// unlock the object |
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_rwlock._internal_lock.unlock(); |
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} // PEG_SEM_WRITE |
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else |
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{ |
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//----------------------------------------------------------------- |
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// Read Lock Step 1: Wait for the existing writer (if any) to clear |
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//----------------------------------------------------------------- |
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if (milliseconds == 0) // fast wait |
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{ |
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if (_writers.get() > 0) |
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{ |
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_rwlock._internal_lock.unlock(); |
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// caught.reset(new WaitFailed(Threads::self())); |
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caughtWaitFailed = WaitFailed(Threads::self()); |
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goto throw_from_here; |
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} |
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} |
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else if (milliseconds == -1) // infinite wait |
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{ |
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while (_writers.get() > 0) |
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Threads::yield(); |
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} |
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else // timed wait |
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{ |
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struct timeval start, now; |
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Time::gettimeofday(&start); |
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start.tv_usec += (milliseconds * 1000); |
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while (_writers.get() > 0) |
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{ |
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Time::gettimeofday(&now); |
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if ((now.tv_usec > start.tv_usec) || |
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(now.tv_sec > start.tv_sec)) |
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{ |
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_rwlock._internal_lock.unlock(); |
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// caught.reset(new TimeOut(Threads::self())); |
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caughtTimeOut = TimeOut(Threads::self()); |
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goto throw_from_here; |
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} |
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Threads::yield(); |
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Time::gettimeofday(&now); |
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} |
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} |
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//----------------------------------------------------------------- |
// Wait for a reader slot to open up. |
// Read Lock Step 2: wait for a reader slot to open up, then return |
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// At this point there are no writers, but there may be too many |
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// readers. |
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//----------------------------------------------------------------- |
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if (milliseconds == 0) // fast wait |
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{ |
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try |
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{ |
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_rwlock._rlock.try_wait(); |
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} |
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catch(const IPCException &) |
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{ |
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// the wait failed, there must be too many readers |
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// already. |
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// unlock the object |
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caughtTooManyReaders = TooManyReaders(Threads::self()); |
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_rwlock._internal_lock.unlock(); |
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// caught.reset(new TooManyReaders(Threads::self())); |
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} |
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} |
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else if (milliseconds == -1) // infinite wait |
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{ |
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try |
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{ |
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_rwlock._rlock.wait(); | _rwlock._rlock.wait(); |
} |
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catch(const IPCException & e) |
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{ |
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_rwlock._internal_lock.unlock(); |
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caught = e; |
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goto throw_from_here; |
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} |
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} |
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else // timed wait |
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{ |
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try |
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{ |
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_rwlock._rlock.time_wait(milliseconds); |
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} |
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catch(const IPCException & e) |
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{ |
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_rwlock._internal_lock.unlock(); |
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caught = e; |
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goto throw_from_here; |
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} |
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} |
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//----------------------------------------------------------------- |
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// Read Lock Step 3: increment the number of readers, unlock the object, |
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// return |
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//----------------------------------------------------------------- |
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_readers++; |
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_rwlock._internal_lock.unlock(); |
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} |
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throw_from_here: |
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// ATTN: |
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Threads::cleanup_pop(0); |
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} |
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if (Threads::id(caught.get_owner()) != 0) |
// Increment the number of readers. |
throw caught; |
_rwlock._readers++; |
if (Threads::id(caughtWaitFailed.get_owner()) != 0) |
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throw caughtWaitFailed; |
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if (Threads::id(caughtTimeOut.get_owner()) != 0) |
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throw caughtTimeOut; |
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if (Threads::id(caughtTooManyReaders.get_owner()) != 0) |
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throw caughtTooManyReaders; |
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return; |
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} | } |
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//--------------------------------------------------------------------- |
void ReadWriteSem::waitWrite() |
void ReadWriteSem::wait(Uint32 mode, ThreadType caller) |
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{ | { |
timed_wait(mode, caller, -1); |
// Lock the internal mutex to ensure only one waiter is processed at a time. |
} |
AutoMutex lock(_rwlock._internal_lock); |
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void ReadWriteSem::try_wait(Uint32 mode, ThreadType caller) |
// Allow all the readers to exit. |
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while (_rwlock._readers.get() > 0) |
{ | { |
timed_wait(mode, caller, 0); |
Threads::yield(); |
} | } |
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// Obtain the write mutex. |
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_rwlock._wlock.lock(); |
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void ReadWriteSem::unlock(Uint32 mode, ThreadType caller) |
// Set the writer count to one. |
{ |
_rwlock._writers = 1; |
if (mode == PEG_SEM_WRITE && _writers.get() != 0) |
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{ |
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_writers = 0; |
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_rwlock._wlock.unlock(); |
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} |
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else if (_readers.get() != 0) |
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{ |
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_readers--; |
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_rwlock._rlock.signal(); |
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} |
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} | } |
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int ReadWriteSem::read_count() const |
void ReadWriteSem::unlockRead() |
{ | { |
return (_readers.get()); |
PEGASUS_ASSERT(_rwlock._readers.get() > 0); |
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_rwlock._readers--; |
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_rwlock._rlock.signal(); |
} | } |
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int ReadWriteSem::write_count() const |
void ReadWriteSem::unlockWrite() |
{ | { |
return (_writers.get()); |
PEGASUS_ASSERT(_rwlock._writers.get() == 1); |
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_rwlock._writers = 0; |
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_rwlock._wlock.unlock(); |
} | } |
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#endif /* !PEGASUS_USE_SEMAPHORE_RWLOCK */ | #endif /* !PEGASUS_USE_SEMAPHORE_RWLOCK */ |