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Diff for /pegasus/src/Pegasus/Common/ReadWriteSem.cpp between version 1.1.2.11 and 1.12

version 1.1.2.11, 2006/07/29 01:18:27 version 1.12, 2008/09/09 17:38:27
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 // //
 //============================================================================== //==============================================================================
 // //
 // Author: Mike Day (mdday@us.ibm.com)  
 //  
 // Reworked By: Mike Brasher (m.brasher@inovadevelopment.com)  
 //  
 //%///////////////////////////////////////////////////////////////////////////// //%/////////////////////////////////////////////////////////////////////////////
  
 #include "ReadWriteSem.h" #include "ReadWriteSem.h"
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 #ifdef PEGASUS_USE_POSIX_RWLOCK #ifdef PEGASUS_USE_POSIX_RWLOCK
  
 ReadWriteSem::ReadWriteSem():_readers(0), _writers(0)  ReadWriteSem::ReadWriteSem()
 { {
     pthread_rwlock_init(&_rwlock.rwlock, NULL);     pthread_rwlock_init(&_rwlock.rwlock, NULL);
     Threads::clear(_rwlock.owner);  
 } }
  
 ReadWriteSem::~ReadWriteSem() ReadWriteSem::~ReadWriteSem()
 { {
       int r = 0;
     while (EBUSY == pthread_rwlock_destroy(&_rwlock.rwlock))      while ((r = pthread_rwlock_destroy(&_rwlock.rwlock)) == EBUSY ||
              (r == -1 && errno == EBUSY))
     {     {
         Threads::yield();         Threads::yield();
     }     }
 } }
  
 void ReadWriteSem::wait(Uint32 mode, ThreadType caller)  void ReadWriteSem::waitRead()
 { {
     int errorcode;      if (pthread_rwlock_rdlock(&_rwlock.rwlock) != 0)
     if (mode == PEG_SEM_READ)  
     {     {
         if (0 == (errorcode = pthread_rwlock_rdlock(&_rwlock.rwlock)))          throw WaitFailed(Threads::self());
         {  
             _readers++;  
             return;  
         }  
     }  
     else if (mode == PEG_SEM_WRITE)  
     {  
         if (0 == (errorcode = pthread_rwlock_wrlock(&_rwlock.rwlock)))  
         {  
             _rwlock.owner = caller;  
             _writers++;  
             return;  
         }  
     }  
     else  
         throw(Permission(Threads::self()));  
   
     if (errorcode == EDEADLK)  
         throw(Deadlock(_rwlock.owner));  
     else  
         throw(WaitFailed(Threads::self()));  
 }  
   
 void ReadWriteSem::try_wait(Uint32 mode, ThreadType caller)  
 {  
     int errorcode = 0;  
     if (mode == PEG_SEM_READ)  
     {  
         if (0 == (errorcode = pthread_rwlock_tryrdlock(&_rwlock.rwlock)))  
         {  
             _readers++;  
             return;  
         }  
     }  
     else if (mode == PEG_SEM_WRITE)  
     {  
         if (0 == (errorcode = pthread_rwlock_trywrlock(&_rwlock.rwlock)))  
         {  
             _writers++;  
             _rwlock.owner = caller;  
             return;  
         }  
     }     }
     else  
         throw(Permission(Threads::self()));  
   
     if (errorcode == EBUSY)  
         throw(AlreadyLocked(_rwlock.owner));  
     else if (errorcode == EDEADLK)  
         throw(Deadlock(_rwlock.owner));  
     else  
         throw(WaitFailed(Threads::self()));  
 } }
  
   void ReadWriteSem::waitWrite()
 // timedrdlock and timedwrlock are not supported on HPUX  
 // mdday Sun Aug  5 14:21:00 2001  
 void ReadWriteSem::timed_wait(Uint32 mode,  
                               ThreadType caller, int milliseconds)  
 {  
     int errorcode = 0, timeout = 0;  
     struct timeval now, finish, remaining;  
     Uint32 usec;  
   
     gettimeofday(&finish, NULL);  
     finish.tv_sec += (milliseconds / 1000);  
     milliseconds %= 1000;  
     usec = finish.tv_usec + (milliseconds * 1000);  
     finish.tv_sec += (usec / 1000000);  
     finish.tv_usec = usec % 1000000;  
   
     if (mode == PEG_SEM_READ)  
     {     {
         do      if (pthread_rwlock_wrlock(&_rwlock.rwlock) != 0)
         {         {
             errorcode = pthread_rwlock_tryrdlock(&_rwlock.rwlock);          throw WaitFailed(Threads::self());
             gettimeofday(&now, NULL);  
         }         }
         while (errorcode == EBUSY &&  
                (0 == (timeout = Time::subtract(&remaining, &finish, &now))));  
         if (0 == errorcode)  
         {  
             _readers++;  
             return;  
         }         }
     }  
     else if (mode == PEG_SEM_WRITE)  
     {  
         do  
         {  
             errorcode = pthread_rwlock_trywrlock(&_rwlock.rwlock);  
             gettimeofday(&now, NULL);  
         }  
         while (errorcode == EBUSY &&  
                (0 == (timeout = Time::subtract(&remaining, &finish, &now))));  
  
         if (0 == errorcode)  void ReadWriteSem::unlockRead()
         {         {
             _writers++;      int rc = pthread_rwlock_unlock(&_rwlock.rwlock);
             _rwlock.owner = caller;      // All documented error codes represent coding errors.
             return;      PEGASUS_ASSERT(rc == 0);
         }  
     }  
     else  
         throw(Permission(Threads::self()));  
     if (timeout != 0)  
         throw(TimeOut(_rwlock.owner));  
     else if (errorcode == EDEADLK)  
         throw(Deadlock(_rwlock.owner));  
     else  
         throw(WaitFailed(Threads::self()));  
 }  
   
 void ReadWriteSem::unlock(Uint32 mode, ThreadType caller)  
 {  
     ThreadType owner;  
   
     if (mode == PEG_SEM_WRITE)  
     {  
         owner = _rwlock.owner;  
         Threads::clear(_rwlock.owner);  
     }  
     if (0 != pthread_rwlock_unlock(&_rwlock.rwlock))  
     {  
         _rwlock.owner = owner;  
         throw(Permission(Threads::self()));  
     }  
     if (mode == PEG_SEM_READ && _readers.get() != 0)  
         _readers--;  
     else if (_writers.get() != 0)  
         _writers--;  
 } }
  
 int ReadWriteSem::read_count() const  void ReadWriteSem::unlockWrite()
 { {
     return (_readers.get());      int rc = pthread_rwlock_unlock(&_rwlock.rwlock);
 }      // All documented error codes represent coding errors.
       PEGASUS_ASSERT(rc == 0);
 int ReadWriteSem::write_count() const  
 {  
     return (_writers.get());  
 } }
  
 #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
  
 #if 0  ReadWriteSem::ReadWriteSem() : _rwlock()
 void extricate_read_write(void *parm)  
 {  
     ReadWriteSem *rws = (ReadWriteSem *) parm;  
     ThreadType myself = Threads::self();  
   
     if (Threads::equal(rws->_rwlock._wlock.get_owner(), myself))  
         rws->_rwlock._wlock.unlock();  
     else if (rws->_readers.get() > 0)  
         rws->_rwlock._rlock.signal();  
   
     if (Threads::equal(rws->_rwlock._internal_lock.get_owner(), myself))  
         rws->_rwlock._internal_lock.unlock();  
 }  
 #endif  
   
   
 ReadWriteSem::ReadWriteSem():_readers(0), _writers(0), _rwlock()  
 { {
 } }
  
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     {     {
         _rwlock._internal_lock.lock();         _rwlock._internal_lock.lock();
     }     }
     catch(Deadlock & d)  
     {  
         d = d;                  // no problem - we own the lock, which is  
                                 // what we want  
     }  
     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();
 } }
  
   void ReadWriteSem::waitRead()
   
   
   
   
 //-----------------------------------------------------------------  
 // if milliseconds == -1, wait indefinately  
 // if milliseconds == 0, fast wait  
 //-----------------------------------------------------------------  
 void ReadWriteSem::timed_wait(Uint32 mode, ThreadType caller,  
                               int milliseconds)  
 {  
 //-----------------------------------------------------------------  
 // Lock this object to maintain integrity while we decide  
 // exactly what to do next.  
 //-----------------------------------------------------------------  
     // AutoPtr<IPCException> caught;  
     // IPCException caught((ThreadType)0);  
     // WaitFailed caughtWaitFailed((ThreadType)0);  
     // TimeOut caughtTimeOut((ThreadType)0);  
     // TooManyReaders caughtTooManyReaders((ThreadType)0);  
   
     ThreadType zero;  
     IPCException caught(zero);  
     WaitFailed caughtWaitFailed(zero);  
     TimeOut caughtTimeOut(zero);  
     TooManyReaders caughtTooManyReaders(zero);  
   
     // cleanup stack frame  
     {     {
         // Threads::cleanup_push(extricate_read_write, this);      // Lock the internal mutex to ensure only one waiter is processed at a time.
       AutoMutex lock(_rwlock._internal_lock);
  
         try      // Wait for the existing writer (if any) to clear.
       while (_rwlock._writers.get() > 0)
         {         {
             if (milliseconds == 0)  
                 _rwlock._internal_lock.try_lock();  
             else if (milliseconds == -1)  
                 _rwlock._internal_lock.lock();  
             else  
                 _rwlock._internal_lock.timed_lock(milliseconds);  
         }  
         catch(const IPCException & e)  
         {  
             caught = e;  
             goto throw_from_here;  
         }  
   
         if (mode == PEG_SEM_WRITE)  
         {  
 //-----------------------------------------------------------------  
 // Write Lock Step 1: lock the object and allow all the readers to exit  
 //-----------------------------------------------------------------  
   
   
             if (milliseconds == 0)      // fast wait  
             {  
                 if (_readers.get() > 0)  
                 {  
                     _rwlock._internal_lock.unlock();  
                     // caught.reset(new WaitFailed(Threads::self()));  
                     caughtWaitFailed = WaitFailed(Threads::self());  
                     goto throw_from_here;  
                 }  
             }  
             else if (milliseconds == -1)        // infinite wait  
             {  
                 while (_readers.get() > 0)  
                     Threads::yield();                     Threads::yield();
             }             }
             else                // timed wait  
             {  
                 struct timeval start, now;  
                 Time::gettimeofday(&start);  
                 start.tv_usec += (1000 * milliseconds);  
                 while (_readers.get() > 0)  
                 {  
                     Time::gettimeofday(&now);  
                     if ((now.tv_usec > start.tv_usec) ||  
                         now.tv_sec > start.tv_sec)  
                     {  
                         _rwlock._internal_lock.unlock();  
                         // caught.reset(new TimeOut(Threads::self()));  
                         caughtTimeOut = TimeOut(Threads::self());  
                         goto throw_from_here;  
                     }  
                     Threads::yield();  
                 }  
             }  
 //-----------------------------------------------------------------  
 // Write Lock Step 2: Obtain the Write Mutex  
 //  Although there are no readers, there may be a writer  
 //-----------------------------------------------------------------  
             if (milliseconds == 0)      // fast wait  
             {  
                 try  
                 {  
                     _rwlock._wlock.try_lock();  
                 }  
                 catch(IPCException & e)  
                 {  
                     _rwlock._internal_lock.unlock();  
                     caught = e;  
                     goto throw_from_here;  
                 }  
             }  
             else if (milliseconds == -1)        // infinite wait  
             {  
                 try  
                 {  
                     _rwlock._wlock.lock();  
                 }  
                 catch(const IPCException & e)  
                 {  
                     _rwlock._internal_lock.unlock();  
                     caught = e;  
                     goto throw_from_here;  
                 }  
             }  
             else                // timed wait  
             {  
                 try  
                 {  
                     _rwlock._wlock.timed_lock(milliseconds);  
                 }  
                 catch(const IPCException & e)  
                 {  
                     _rwlock._internal_lock.unlock();  
                     caught = e;  
                     goto throw_from_here;  
                 }  
             }  
   
 //-----------------------------------------------------------------  
 // Write Lock Step 3: set the writer count to one, unlock the object  
 //   There are no readers and we are the only writer !  
 //-----------------------------------------------------------------  
             _writers = 1;  
             // set the owner  
             _rwlock._owner = Threads::self();  
             // unlock the object  
             _rwlock._internal_lock.unlock();  
         }                       // PEG_SEM_WRITE  
         else  
         {  
 //-----------------------------------------------------------------  
 // Read Lock Step 1: Wait for the existing writer (if any) to clear  
 //-----------------------------------------------------------------  
             if (milliseconds == 0)      // fast wait  
             {  
                 if (_writers.get() > 0)  
                 {  
                     _rwlock._internal_lock.unlock();  
                     // caught.reset(new WaitFailed(Threads::self()));  
                     caughtWaitFailed = WaitFailed(Threads::self());  
                     goto throw_from_here;  
                 }  
             }  
             else if (milliseconds == -1)        // infinite wait  
             {  
                 while (_writers.get() > 0)  
                     Threads::yield();  
             }  
             else                // timed wait  
             {  
                 struct timeval start, now;  
                 Time::gettimeofday(&start);  
                 start.tv_usec += (milliseconds * 1000);  
   
                 while (_writers.get() > 0)  
                 {  
                     Time::gettimeofday(&now);  
                     if ((now.tv_usec > start.tv_usec) ||  
                         (now.tv_sec > start.tv_sec))  
                     {  
                         _rwlock._internal_lock.unlock();  
                         // caught.reset(new TimeOut(Threads::self()));  
                         caughtTimeOut = TimeOut(Threads::self());  
                         goto throw_from_here;  
                     }  
                     Threads::yield();  
                     Time::gettimeofday(&now);  
                 }  
             }  
  
 //-----------------------------------------------------------------      // Wait for a reader slot to open up.
 // Read Lock Step 2: wait for a reader slot to open up, then return  
 //  At this point there are no writers, but there may be too many  
 //  readers.  
 //-----------------------------------------------------------------  
             if (milliseconds == 0)      // fast wait  
             {  
                 try  
                 {  
                     _rwlock._rlock.try_wait();  
                 }  
                 catch(const IPCException &)  
                 {  
                     // the wait failed, there must be too many readers  
                     // already.  
                     // unlock the object  
                     caughtTooManyReaders = TooManyReaders(Threads::self());  
                     _rwlock._internal_lock.unlock();  
                     // caught.reset(new TooManyReaders(Threads::self()));  
                 }  
             }  
             else if (milliseconds == -1)        // infinite wait  
             {  
                 try  
                 {  
                     _rwlock._rlock.wait();                     _rwlock._rlock.wait();
                 }  
                 catch(const IPCException & e)  
                 {  
                     _rwlock._internal_lock.unlock();  
                     caught = e;  
                     goto throw_from_here;  
                 }  
             }  
             else                // timed wait  
             {  
                 try  
                 {  
                     _rwlock._rlock.time_wait(milliseconds);  
                 }  
                 catch(const IPCException & e)  
                 {  
                     _rwlock._internal_lock.unlock();  
                     caught = e;  
                     goto throw_from_here;  
                 }  
             }  
   
 //-----------------------------------------------------------------  
 // Read Lock Step 3: increment the number of readers, unlock the object,  
 // return  
 //-----------------------------------------------------------------  
             _readers++;  
             _rwlock._internal_lock.unlock();  
         }  
       throw_from_here:  
         // ATTN:  
         Threads::cleanup_pop(0);  
     }  
  
     if (Threads::id(caught.get_owner()) != 0)      // Increment the number of readers.
         throw caught;      _rwlock._readers++;
     if (Threads::id(caughtWaitFailed.get_owner()) != 0)  
         throw caughtWaitFailed;  
     if (Threads::id(caughtTimeOut.get_owner()) != 0)  
         throw caughtTimeOut;  
     if (Threads::id(caughtTooManyReaders.get_owner()) != 0)  
         throw caughtTooManyReaders;  
     return;  
 } }
  
 //---------------------------------------------------------------------  void ReadWriteSem::waitWrite()
 void ReadWriteSem::wait(Uint32 mode, ThreadType caller)  
 { {
     timed_wait(mode, caller, -1);      // Lock the internal mutex to ensure only one waiter is processed at a time.
 }      AutoMutex lock(_rwlock._internal_lock);
  
 void ReadWriteSem::try_wait(Uint32 mode, ThreadType caller)      // Allow all the readers to exit.
       while (_rwlock._readers.get() > 0)
 { {
     timed_wait(mode, caller, 0);          Threads::yield();
 } }
  
       // Obtain the write mutex.
       _rwlock._wlock.lock();
  
 void ReadWriteSem::unlock(Uint32 mode, ThreadType caller)      // Set the writer count to one.
 {      _rwlock._writers = 1;
     if (mode == PEG_SEM_WRITE && _writers.get() != 0)  
     {  
         _writers = 0;  
         _rwlock._wlock.unlock();  
     }  
     else if (_readers.get() != 0)  
     {  
         _readers--;  
         _rwlock._rlock.signal();  
     }  
 } }
  
 int ReadWriteSem::read_count() const  void ReadWriteSem::unlockRead()
 { {
     return (_readers.get());      PEGASUS_ASSERT(_rwlock._readers.get() > 0);
       _rwlock._readers--;
       _rwlock._rlock.signal();
 } }
  
 int ReadWriteSem::write_count() const  void ReadWriteSem::unlockWrite()
 { {
     return (_writers.get());      PEGASUS_ASSERT(_rwlock._writers.get() == 1);
       _rwlock._writers = 0;
       _rwlock._wlock.unlock();
 } }
  
 #endif /* !PEGASUS_USE_SEMAPHORE_RWLOCK */ #endif /* !PEGASUS_USE_SEMAPHORE_RWLOCK */

Legend:
Removed from v.1.1.2.11  
changed lines
  Added in v.1.12
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