src/dataqueue.h

   1 ///
   2 /// \file       dataqueue.h
   3 ///             FIFO queue of Data objects
   4 ///
   5
   6 /*
   7     Copyright (C) 2007-2010, Net Direct Inc. (http://www.netdirect.ca/)
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License as published by
  11     the Free Software Foundation; either version 2 of the License, or
  12     (at your option) any later version.
  13
  14     This program is distributed in the hope that it will be useful,
  15     but WITHOUT ANY WARRANTY; without even the implied warranty of
  16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  17
  18     See the GNU General Public License in the COPYING file at the
  19     root directory of this project for more details.
  20 */
  21
  22 #ifndef __BARRY_DATAQUEUE_H__
  23 #define __BARRY_DATAQUEUE_H__
  24
  25 #include <queue>
  26 #include <pthread.h>
  27
  28 namespace Barry {
  29
  30 class Data;
  31
  32 //
  33 // DataQueue class
  34 //
  35 /// This class provides a thread aware fifo queue for Data objects,
  36 /// providing memory management for all Data object pointers it contains.
  37 ///
  38 /// It uses similar member names as std::queue<>, for consistency.
  39 ///
  40 class DataQueue
  41 {
  42         typedef std::queue<Data*>                       queue_type;
  43
  44         pthread_mutex_t m_waitMutex;
  45         pthread_cond_t m_waitCond;
  46
  47         mutable pthread_mutex_t m_accessMutex;  // locked for each access of m_queue
  48
  49         queue_type m_queue;
  50
  51 public:
  52         DataQueue();
  53         ~DataQueue();           // frees all data in the queue
  54
  55         // Pushes data into the end of the queue.
  56         // The queue owns this pointer as soon as the function is
  57         // called.  In the case of an exception, it will be freed.
  58         // Performs a thread broadcast once new data has been added.
  59         void push(Data *data);
  60
  61         // Pops the next element off the front of the queue.
  62         // Returns 0 if empty.
  63         // The queue no longer owns this pointer upon return.
  64         Data* pop();
  65
  66         // Pops the next element off the front of the queue, and
  67         // waits until one exists if empty.  If still no data
  68         // on timeout, returns null.
  69         // Timeout specified in milliseconds.  Default is wait forever.
  70         Data* wait_pop(int timeout = -1);
  71
  72         // Pops all data from other and appends it to this.
  73         // After calling this function, other will be empty, and
  74         // this will contain all its data.
  75         // In the case of an exception, any uncopied data will
  76         // remain in other.
  77         void append_from(DataQueue &other);
  78
  79         bool empty() const;     // return true if empty
  80         size_t size() const;
  81 };
  82
  83 } // namespace Barry
  84
  85 #endif
  86