src/threadpool.cpp

   1 /*
   2 libfmail: Threaded Load handler with Thread Pool
   3
   4 Copyright (C) 2007  Carlos Daniel Ruvalcaba Valenzuela <clsdaniel@gmail.com>
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License along
  17 with this program; if not, write to the Free Software Foundation, Inc.,
  18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include <libfmail.h>
  22
  23 /* Worker Thread, has a sempahore for signaling */
  24 class ThreadLoadHandler : public Thread, public Semaphore{
  25 private:
  26         Socket *s;
  27         ProtocolHandler *ph;
  28 public:
  29         int onRun;
  30         ThreadLoadHandler(ProtocolHandler *pht) : Thread(), Semaphore(){
  31                 s = NULL;
  32                 ph = pht;
  33                 onRun = 1;
  34         }
  35
  36         /* Set client socket */
  37         void setSocket(Socket *sock){
  38                 s = sock;
  39         }
  40
  41         /* Deprecated */
  42         int isReady(){
  43                 return 0;
  44         }
  45
  46         /* Thread code */
  47         int Run(){
  48                 while (onRun){
  49                         /* Wait for a job, decrement semaphore */
  50                         Wait();
  51
  52                         if (s){
  53                                 /* Run the handler */
  54                                 ph->Handle(s);
  55                         }
  56
  57                         s = NULL;
  58
  59                         /* Decrement the semaphore */
  60                         Wait();
  61                 }
  62                 return 0;
  63         }
  64 };
  65
  66 ThreadLoad::ThreadLoad(ProtocolHandler *ph, int tpoolSize){
  67         int i;
  68         poolSize = tpoolSize;
  69         ThreadLoadHandler **tpool;
  70
  71         /* Allocate an array for the worker threads */
  72         pool = (void**)malloc(sizeof(ThreadLoadHandler*) * poolSize);
  73         tpool = (ThreadLoadHandler**)pool;
  74
  75         /* Create and start worker threads, all should just wait for job */
  76         for (i = 0; i < poolSize; i++){
  77                 tpool[i] = new ThreadLoadHandler(ph);
  78                 tpool[i]->Start();
  79         }
  80 }
  81
  82 ThreadLoad::~ThreadLoad(){
  83         int unclean, i;
  84         ThreadLoadHandler **tpool;
  85
  86         tpool = (ThreadLoadHandler**)pool;
  87
  88         unclean = 1;
  89         while(unclean){
  90                 unclean = 0;
  91                 for(i = 0; i < poolSize; i++){
  92                         if (tpool[i]->onRun){
  93                                 if (tpool[i]->isReady()){
  94                                         tpool[i]->onRun = 0;
  95                                         tpool[i]->Post();
  96                                 }else{
  97                                         unclean = 1;
  98                                 }
  99                         }
 100                 }
 101         }
 102
 103         for(i = 0; i < poolSize; i++){
 104                 delete tpool[i];
 105         }
 106         free(pool);
 107         pool = NULL;
 108 }
 109
 110 /* Boss thread handling code */
 111 int ThreadLoad::Dispatch(Socket *sock, ProtocolHandler *ph){
 112         int i, dispatched;
 113         ThreadLoadHandler **tpool;
 114
 115         (void)ph;
 116         tpool = (ThreadLoadHandler**)pool;
 117
 118         dispatched = 0;
 119         i = 0;
 120
 121         while (dispatched == 0){
 122                 /* Check semaphore value, if 0 the thread is waiting for work */
 123                 if (tpool[i]->getValue() == 0){
 124                         /* Handle the socket to the thread (work) */
 125                         tpool[i]->setSocket(sock);
 126
 127                         /* Increment twice the semaphore, this to prevent
 128                          * handling work to a thread already doing something but
 129                          * with semaphore value of 0 */
 130                         tpool[i]->Post();
 131                         tpool[i]->Post();
 132                         dispatched = 1;
 133                 }
 134                 i++;
 135                 /* Wrap i around pool size */
 136                 if (i == poolSize)
 137                         i = 0;
 138         }
 139         return 0;
 140 }
 141