src/dataqueue.h

   1 ///
   2 /// \file       dataqueue.h
   3 ///             FIFO queue of Data objects
   4 ///
   5
   6 /*
   7     Copyright (C) 2007-2012, 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 <list>
  26 #include <pthread.h>
  27 #include <iosfwd>
  28
  29 namespace Barry {
  30
  31 class Data;
  32
  33 //
  34 // DataQueue class
  35 //
  36 /// This class provides a thread aware fifo queue for Data objects,
  37 /// providing memory management for all Data object pointers it contains.
  38 ///
  39 /// It uses similar member names as std::queue<>, for consistency.
  40 ///
  41 class DataQueue
  42 {
  43         // always use the raw_push() and raw_pop() functions
  44         typedef std::list<Data*>                        queue_type;
  45
  46         pthread_mutex_t m_waitMutex;
  47         pthread_cond_t m_waitCond;
  48
  49         mutable pthread_mutex_t m_accessMutex;  // locked for each access of m_queue
  50
  51         queue_type m_queue;
  52
  53 protected:
  54         void raw_push(Data *data);
  55         Data* raw_pop();
  56
  57 public:
  58         DataQueue();
  59         ~DataQueue();           // frees all data in the queue
  60
  61         // Pushes data into the end of the queue.
  62         // The queue owns this pointer as soon as the function is
  63         // called.  In the case of an exception, it will be freed.
  64         // Performs a thread broadcast once new data has been added.
  65         void push(Data *data);
  66
  67         // Pops the next element off the front of the queue.
  68         // Returns 0 if empty.
  69         // The queue no longer owns this pointer upon return.
  70         Data* pop();
  71
  72         // Pops the next element off the front of the queue, and
  73         // waits until one exists if empty.  If still no data
  74         // on timeout, returns null.
  75         // Timeout specified in milliseconds.  Default is wait forever.
  76         Data* wait_pop(int timeout = -1);
  77
  78         // Pops all data from other and appends it to this.
  79         // After calling this function, other will be empty, and
  80         // this will contain all its data.
  81         // In the case of an exception, any uncopied data will
  82         // remain in other.
  83         void append_from(DataQueue &other);
  84
  85         bool empty() const;     // return true if empty
  86         size_t size() const;
  87
  88         void DumpAll(std::ostream &os) const;
  89 };
  90
  91 inline std::ostream& operator<< (std::ostream &os, const DataQueue &dq)
  92 {
  93         dq.DumpAll(os);
  94         return os;
  95 }
  96
  97 } // namespace Barry
  98
  99 #endif
 100