Imported MaNGOS revision 6767 from http://mangos.svn.sourceforge.net/svnroot/mangos/trunk/

dep/include/zthread/MonitoredQueue.h

@@ -0,0 +1,345 @@
+/*
+ * Copyright (c) 2005, Eric Crahen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is furnished
+ * to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __ZTMONITOREDQUEUE_H__
+#define __ZTMONITOREDQUEUE_H__
+
+#include "zthread/Condition.h"
+#include "zthread/Guard.h"
+#include "zthread/Queue.h"
+
+#include <deque>
+
+namespace ZThread {
+
+  /**
+   * @class MonitoredQueue
+   * @author Eric Crahen <http://www.code-foo.com>
+   * @date <2003-07-16T20:23:28-0400>
+   * @version 2.3.0
+   *
+   * A MonitoredQueue is a Queue implementation that provides  serialized access to the 
+   * items added to it. 
+   *
+   * - Threads calling the empty() methods will be blocked until the BoundedQueue becomes empty. 
+   * - Threads calling the next() methods will be blocked until the BoundedQueue has a value to
+   *   return. 
+   *
+   * @see Queue
+   */
+  template <class T, class LockType, typename StorageType=std::deque<T> >
+    class MonitoredQueue : public Queue<T>, public Lockable {
+
+      //! Serialize access
+      LockType _lock;
+
+      //! Signaled on not empty
+      Condition _notEmpty;
+
+      //! Signaled on empty
+      Condition _isEmpty;
+
+      //! Storage backing the queue
+      StorageType _queue;
+
+      //! Cancellation flag
+      volatile bool _canceled;
+
+      public:
+
+      //! Create a new MonitoredQueue
+      MonitoredQueue() 
+        : _notEmpty(_lock), _isEmpty(_lock), _canceled(false) {}
+
+      //! Destroy a MonitoredQueue, delete remaining items
+      virtual ~MonitoredQueue() { }
+
+      /**
+       * Add a value to this Queue. 
+       *
+       * @param item value to be added to the Queue
+       * 
+       * @exception Cancellation_Exception thrown if this Queue has been canceled.
+       * @exception Interrupted_Exception thrown if the thread was interrupted while waiting
+       *            to add a value
+       *
+       * @pre  The Queue should not have been canceled prior to the invocation of this function.
+       * @post If no exception is thrown, a copy of <i>item</i> will have been added to the Queue.
+       *
+       * @see Queue::add(const T& item)
+       */
+      virtual void add(const T& item) {
+
+        Guard<LockType> g(_lock);
+    
+        // Allow no further additions in the canceled state
+        if(_canceled)
+          throw Cancellation_Exception();
+
+        _queue.push_back( item );
+
+        _notEmpty.signal(); // Wake one waiter
+
+      }
+
+      /**
+       * Add a value to this Queue. 
+       *
+       * @param item value to be added to the Queue
+       * @param timeout maximum amount of time (milliseconds) this method may block
+       *        the calling thread.
+       *
+       * @return 
+       *   - <em>true</em> if a copy of <i>item</i> can be added before <i>timeout</i> 
+       *     milliseconds elapse.
+       *   - <em>false</em> otherwise.
+       *
+       * @exception Cancellation_Exception thrown if this Queue has been canceled.
+       * @exception Interrupted_Exception thrown if the thread was interrupted while waiting
+       *            to add a value
+       *
+       * @pre  The Queue should not have been canceled prior to the invocation of this function.
+       * @post If no exception is thrown, a copy of <i>item</i> will have been added to the Queue.
+       *
+       * @see Queue::add(const T& item, unsigned long timeout)
+       */
+      virtual bool add(const T& item, unsigned long timeout) {
+  
+        try {
+
+          Guard<LockType> g(_lock, timeout);
+      
+          if(_canceled)
+            throw Cancellation_Exception();
+      
+          _queue.push_back(item);
+
+          _notEmpty.signal();
+
+        } catch(Timeout_Exception&) { return false; }
+ 
+        return true;    
+
+      }
+
+      /**
+       * Retrieve and remove a value from this Queue.
+       *
+       * If invoked when there are no values present to return then the calling thread 
+       * will be blocked until a value arrives in the Queue.
+       *
+       * @return <em>T</em> next available value
+       * 
+       * @exception Cancellation_Exception thrown if this Queue has been canceled.
+       * @exception Interrupted_Exception thrown if the thread was interrupted while waiting
+       *            to retrieve a value
+       *
+       * @pre  The Queue should not have been canceled prior to the invocation of this function.
+       * @post The value returned will have been removed from the Queue.
+       */
+      virtual T next() {
+      
+        Guard<LockType> g(_lock);
+      
+        while (_queue.empty() && !_canceled) 
+          _notEmpty.wait();
+    
+        if(_queue.empty()) // Queue canceled
+          throw Cancellation_Exception();  
+      
+        T item = _queue.front();
+        _queue.pop_front();
+
+        if(_queue.empty()) // Wake empty waiters
+          _isEmpty.broadcast();
+
+        return item;
+
+      }
+
+      /**
+       * Retrieve and remove a value from this Queue.
+       *
+       * If invoked when there are no values present to return then the calling thread 
+       * will be blocked until a value arrives in the Queue.
+       *
+       * @param timeout maximum amount of time (milliseconds) this method may block
+       *        the calling thread.
+       *
+       * @return <em>T</em> next available value
+       * 
+       * @exception Cancellation_Exception thrown if this Queue has been canceled.
+       * @exception Timeout_Exception thrown if the timeout expires before a value
+       *            can be retrieved.
+       *
+       * @pre  The Queue should not have been canceled prior to the invocation of this function.
+       * @post The value returned will have been removed from the Queue.
+       */
+      virtual T next(unsigned long timeout) {
+  
+        Guard<LockType> g(_lock, timeout);
+      
+        while(_queue.empty() && !_canceled) {
+          if(!_notEmpty.wait(timeout))
+            throw Timeout_Exception();
+        }
+
+        if( _queue.empty()) // Queue canceled
+          throw Cancellation_Exception();  
+
+        T item = _queue.front();
+        _queue.pop_front();
+
+        if(_queue.empty()) // Wake empty waiters
+          _isEmpty.broadcast();
+
+        return item;
+
+      }
+
+
+      /**
+       * Cancel this queue. 
+       * 
+       * @post Any threads blocked by a next() function will throw a Cancellation_Exception.
+       * 
+       * @see Queue::cancel()
+       */
+      virtual void cancel() {
+
+        Guard<LockType> g(_lock);
+
+        _canceled = true;
+        _notEmpty.broadcast(); // Wake next() waiters
+
+      }
+
+      /**
+       * @see Queue::isCanceled()
+       */
+      virtual bool isCanceled() {
+  
+        // Faster check since the queue will not become un-canceled
+        if(_canceled)
+          return true;
+    
+        Guard<LockType> g(_lock);
+
+        return _canceled;
+
+      }
+
+
+      /**
+       * @see Queue::size()
+       */
+      virtual size_t size() {
+
+        Guard<LockType> g(_lock);
+        return _queue.size();
+
+      }
+
+      /**
+       * @see Queue::size(unsigned long timeout)
+       */
+      virtual size_t size(unsigned long timeout) {
+
+        Guard<LockType> g(_lock, timeout);
+        return _queue.size();
+
+      }
+
+      /**
+       * Test whether any values are available in this Queue.
+       *
+       * The calling thread is blocked until there are no values present 
+       * in the Queue.
+       * 
+       * @return 
+       *  - <em>true</em> if there are no values available.
+       *  - <em>false</em> if there <i>are</i> values available.
+       *
+       * @see Queue::empty()
+       */
+      virtual bool empty() {
+
+        Guard<LockType> g(_lock);
+
+        while(!_queue.empty()) // Wait for an empty signal
+          _isEmpty.wait();
+    
+        return true;
+
+      }
+
+      /**
+       * Test whether any values are available in this Queue.
+       *
+       * The calling thread is blocked until there are no values present 
+       * in the Queue.
+       * 
+       * @param timeout maximum amount of time (milliseconds) this method may block
+       *        the calling thread.
+       *
+       * @return 
+       *  - <em>true</em> if there are no values available.
+       *  - <em>false</em> if there <i>are</i> values available.
+       *
+       * @exception Timeout_Exception thrown if <i>timeout</i> milliseconds
+       *            expire before a value becomes available
+       *
+       * @see Queue::empty()
+       */
+      virtual bool empty(unsigned long timeout) {
+  
+        Guard<LockType> g(_lock, timeout);
+
+        while(!_queue.empty()) // Wait for an empty signal
+          _isEmpty.wait(timeout);
+    
+        return true;
+
+      }
+
+      public:
+
+      virtual void acquire() {
+        _lock.acquire();
+      }
+
+      virtual bool tryAcquire(unsigned long timeout) {
+        return _lock.tryAcquire(timeout);
+      }
+
+      virtual void release() {
+        _lock.release();
+      }
+
+
+    }; /* MonitoredQueue */
+
+
+} // namespace ZThread
+
+#endif // __ZTMONITOREDQUEUE_H__
+