text: /*
   *  Copyright (C) 2004 Rui Nuno Capela, Steve Harris
   *  Copyright (C) 2008 Nedko Arnaudov
   *  Copyright (C) 2008 Grame
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU Lesser General Public License as published by
   *  the Free Software Foundation; either version 2.1 of the License, or
   *  (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU Lesser General Public License for more details.
   *
   *  You should have received a copy of the GNU Lesser General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   */
  
  #include "JackMessageBuffer.h"
  #include "JackGlobals.h"
  #include "JackError.h"
  #include "JackTime.h"
  
  namespace Jack
  {
  
  JackMessageBuffer* JackMessageBuffer::fInstance = NULL;
  
  JackMessageBuffer::JackMessageBuffer()
      :fInit(NULL),
      fInitArg(NULL),
      fThread(this),
      fGuard(),
      fInBuffer(0),
      fOutBuffer(0),
      fOverruns(0),
      fRunning(false)
  {}
  
  JackMessageBuffer::~JackMessageBuffer()
  {}
  
  bool JackMessageBuffer::Start()
  {
      // Before StartSync()...
      fRunning = true;
      if (fThread.StartSync() == 0) {
          return true;
      } else {
          fRunning = false;
          return false;
      }
  }
  
  bool JackMessageBuffer::Stop()
  {
      if (fOverruns > 0) {
          jack_error("WARNING: %d message buffer overruns!", fOverruns);
      } else {
          jack_log("no message buffer overruns");
      }
  
      if (fGuard.Lock()) {
          fRunning = false;
          fGuard.Signal();
          fGuard.Unlock();
          fThread.Stop();
      } else {
          fThread.Kill();
      }
  
      Flush();
      return true;
  }
  
  void JackMessageBuffer::Flush()
  {
      while (fOutBuffer != fInBuffer) {
          jack_log_function(fBuffers[fOutBuffer].level, fBuffers[fOutBuffer].message);
          fOutBuffer = MB_NEXT(fOutBuffer);
      }
  }
  
  void JackMessageBuffer::AddMessage(int level, const char *message)
  {
      if (fGuard.Trylock()) {
          fBuffers[fInBuffer].level = level;
          strncpy(fBuffers[fInBuffer].message, message, MB_BUFFERSIZE);
          fInBuffer = MB_NEXT(fInBuffer);
          fGuard.Signal();
          fGuard.Unlock();
      } else {            /* lock collision */
          INC_ATOMIC(&fOverruns);
      }
  }
  
  bool JackMessageBuffer::Execute()
  {
      if (fGuard.Lock()) {
          while (fRunning) {
              fGuard.Wait();
              /* the client asked for all threads to run a thread
              initialization callback, which includes us.
              */
              if (fInit) {
                  fInit(fInitArg);
                  fInit = NULL;
                  /* and we're done */
                  fGuard.Signal();
              }
              
              /* releasing the mutex reduces contention */
              fGuard.Unlock();
              Flush();
              fGuard.Lock();
          }
          fGuard.Unlock();
      } else {
          jack_error("JackMessageBuffer::Execute lock cannot be taken");
      }
  
      return false;
  }
  
  bool JackMessageBuffer::Create()
  {
      if (fInstance == NULL) {
          fInstance = new JackMessageBuffer();
          if (!fInstance->Start()) {
              jack_error("JackMessageBuffer::Create cannot start thread");
              delete fInstance;
              fInstance = NULL;
              return false;
          }
      }
  
      return true;
  }
  
  bool JackMessageBuffer::Destroy()
  {
      if (fInstance != NULL) {
          fInstance->Stop();
          delete fInstance;
          fInstance = NULL;
          return true;
      } else {
          return false;
      }
  }
  
  void JackMessageBufferAdd(int level, const char *message)
  {
      if (Jack::JackMessageBuffer::fInstance == NULL) {
          /* Unable to print message with realtime safety. Complain and print it anyway. */
          jack_log_function(LOG_LEVEL_ERROR, "messagebuffer not initialized, skip message");
      } else {
          Jack::JackMessageBuffer::fInstance->AddMessage(level, message);
      }
  }
  
  int JackMessageBuffer::SetInitCallback(JackThreadInitCallback callback, void *arg)
  {
      if (fInstance && callback && fRunning && fGuard.Lock()) {
          /* set up the callback */
          fInitArg = arg;
          fInit = callback;
          
      #ifndef WIN32
          // wake msg buffer thread 
          fGuard.Signal();
          // wait for it to be done  
          fGuard.Wait();
          // and we're done 
          fGuard.Unlock();
      #else
          /*
          The condition variable emulation code does not work reliably on Windows (lost signal).
          So use a "hackish" way to signal/wait for the result.
          Probaly better in the long term : use pthread-win32 (http://sourceware.org/pthreads-win32/`
          */
          fGuard.Unlock();
          int count = 0;
          while (fInit && ++count < 1000) {
              /* wake msg buffer thread */
              fGuard.Signal();
              JackSleep(1000);
          }
          if (count == 1000) goto error;
      #endif
      
          return 0;
      }
      
  error:
      jack_error("JackMessageBuffer::SetInitCallback : callback cannot be executed");
      return -1;
  }
  
  };
  
  