Jack2 1.9.10

JackMessageBuffer.cpp

00001 /*
00002  *  Copyright (C) 2004 Rui Nuno Capela, Steve Harris
00003  *  Copyright (C) 2008 Nedko Arnaudov
00004  *  Copyright (C) 2008 Grame
00005  *
00006  *  This program is free software; you can redistribute it and/or modify
00007  *  it under the terms of the GNU Lesser General Public License as published by
00008  *  the Free Software Foundation; either version 2.1 of the License, or
00009  *  (at your option) any later version.
00010  *
00011  *  This program is distributed in the hope that it will be useful,
00012  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  *  GNU Lesser General Public License for more details.
00015  *
00016  *  You should have received a copy of the GNU Lesser General Public License
00017  *  along with this program; if not, write to the Free Software
00018  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
00019  *
00020  */
00021 
00022 #include "JackMessageBuffer.h"
00023 #include "JackGlobals.h"
00024 #include "JackError.h"
00025 #include "JackTime.h"
00026 
00027 namespace Jack
00028 {
00029 
00030 JackMessageBuffer* JackMessageBuffer::fInstance = NULL;
00031 
00032 JackMessageBuffer::JackMessageBuffer()
00033     :fInit(NULL),
00034     fInitArg(NULL),
00035     fThread(this),
00036     fGuard(),
00037     fInBuffer(0),
00038     fOutBuffer(0),
00039     fOverruns(0),
00040     fRunning(false)
00041 {}
00042 
00043 JackMessageBuffer::~JackMessageBuffer()
00044 {}
00045 
00046 bool JackMessageBuffer::Start()
00047 {
00048     // Before StartSync()...
00049     fRunning = true;
00050     if (fThread.StartSync() == 0) {
00051         return true;
00052     } else {
00053         fRunning = false;
00054         return false;
00055     }
00056 }
00057 
00058 bool JackMessageBuffer::Stop()
00059 {
00060     if (fOverruns > 0) {
00061         jack_error("WARNING: %d message buffer overruns!", fOverruns);
00062     } else {
00063         jack_log("no message buffer overruns");
00064     }
00065 
00066     if (fGuard.Lock()) {
00067         fRunning = false;
00068         fGuard.Signal();
00069         fGuard.Unlock();
00070         fThread.Stop();
00071     } else {
00072         fThread.Kill();
00073     }
00074 
00075     Flush();
00076     return true;
00077 }
00078 
00079 void JackMessageBuffer::Flush()
00080 {
00081     while (fOutBuffer != fInBuffer) {
00082         jack_log_function(fBuffers[fOutBuffer].level, fBuffers[fOutBuffer].message);
00083         fOutBuffer = MB_NEXT(fOutBuffer);
00084     }
00085 }
00086 
00087 void JackMessageBuffer::AddMessage(int level, const char *message)
00088 {
00089     if (fGuard.Trylock()) {
00090         fBuffers[fInBuffer].level = level;
00091         strncpy(fBuffers[fInBuffer].message, message, MB_BUFFERSIZE);
00092         fInBuffer = MB_NEXT(fInBuffer);
00093         fGuard.Signal();
00094         fGuard.Unlock();
00095     } else {            /* lock collision */
00096         INC_ATOMIC(&fOverruns);
00097     }
00098 }
00099 
00100 bool JackMessageBuffer::Execute()
00101 {
00102     if (fGuard.Lock()) {
00103         while (fRunning) {
00104             fGuard.Wait();
00105             /* the client asked for all threads to run a thread
00106             initialization callback, which includes us.
00107             */
00108             if (fInit) {
00109                 fInit(fInitArg);
00110                 fInit = NULL;
00111                 /* and we're done */
00112                 fGuard.Signal();
00113             }
00114             
00115             /* releasing the mutex reduces contention */
00116             fGuard.Unlock();
00117             Flush();
00118             fGuard.Lock();
00119         }
00120         fGuard.Unlock();
00121     } else {
00122         jack_error("JackMessageBuffer::Execute lock cannot be taken");
00123     }
00124 
00125     return false;
00126 }
00127 
00128 bool JackMessageBuffer::Create()
00129 {
00130     if (fInstance == NULL) {
00131         fInstance = new JackMessageBuffer();
00132         if (!fInstance->Start()) {
00133             jack_error("JackMessageBuffer::Create cannot start thread");
00134             delete fInstance;
00135             fInstance = NULL;
00136             return false;
00137         }
00138     }
00139 
00140     return true;
00141 }
00142 
00143 bool JackMessageBuffer::Destroy()
00144 {
00145     if (fInstance != NULL) {
00146         fInstance->Stop();
00147         delete fInstance;
00148         fInstance = NULL;
00149         return true;
00150     } else {
00151         return false;
00152     }
00153 }
00154 
00155 void JackMessageBufferAdd(int level, const char *message)
00156 {
00157     if (Jack::JackMessageBuffer::fInstance == NULL) {
00158         /* Unable to print message with realtime safety. Complain and print it anyway. */
00159         jack_log_function(LOG_LEVEL_ERROR, "messagebuffer not initialized, skip message");
00160     } else {
00161         Jack::JackMessageBuffer::fInstance->AddMessage(level, message);
00162     }
00163 }
00164 
00165 int JackMessageBuffer::SetInitCallback(JackThreadInitCallback callback, void *arg)
00166 {
00167     if (fInstance && callback && fRunning && fGuard.Lock()) {
00168         /* set up the callback */
00169         fInitArg = arg;
00170         fInit = callback;
00171         
00172     #ifndef WIN32
00173         // wake msg buffer thread 
00174         fGuard.Signal();
00175         // wait for it to be done  
00176         fGuard.Wait();
00177         // and we're done 
00178         fGuard.Unlock();
00179     #else
00180         /*
00181         The condition variable emulation code does not work reliably on Windows (lost signal).
00182         So use a "hackish" way to signal/wait for the result.
00183         Probaly better in the long term : use pthread-win32 (http://sourceware.org/pthreads-win32/`
00184         */
00185         fGuard.Unlock();
00186         int count = 0;
00187         while (fInit && ++count < 1000) {
00188             /* wake msg buffer thread */
00189             fGuard.Signal();
00190             JackSleep(1000);
00191         }
00192         if (count == 1000) goto error;
00193     #endif
00194     
00195         return 0;
00196     }
00197     
00198 error:
00199     jack_error("JackMessageBuffer::SetInitCallback : callback cannot be executed");
00200     return -1;
00201 }
00202 
00203 };
00204