SelectInterruptor.cxx

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#include "resip/stack/SelectInterruptor.hxx"

#include <cassert>
#include "rutil/Logger.hxx"

#ifndef WIN32
#include <unistd.h>
#endif

using namespace resip;

#define RESIPROCATE_SUBSYSTEM Subsystem::TRANSPORT

SelectInterruptor::SelectInterruptor()
{
#ifdef WIN32
   mSocket = ::socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);

   sockaddr_in loopback;
   memset(&loopback, 0, sizeof(loopback));
   loopback.sin_family = AF_INET;
   loopback.sin_port = 0;
   loopback.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
   makeSocketNonBlocking(mSocket); //win32 woes
   ::bind( mSocket, reinterpret_cast<sockaddr*>(&loopback), sizeof(loopback));
   memset(&mWakeupAddr, 0, sizeof(mWakeupAddr));
   int len = sizeof(mWakeupAddr);
   int error = getsockname(mSocket, (sockaddr *)&mWakeupAddr, &len);
   assert(error == 0);
   error= connect(mSocket, &mWakeupAddr, sizeof(mWakeupAddr));
   assert(error == 0);
   mReadThing = mSocket;
#else
   int x = pipe(mPipe);
   (void)x;
   assert( x != -1 );
   // make write-side non-blocking to avoid deadlock
   makeSocketNonBlocking(mPipe[1]);
   // make read-side non-blocking so safe to read out entire pipe
   // all in one go (also just safer)
   makeSocketNonBlocking(mPipe[0]);
   mReadThing = mPipe[0];
#endif
}

SelectInterruptor::~SelectInterruptor()
{
#ifdef WIN32
   closesocket(mSocket);
#else
   close(mPipe[0]);
   close(mPipe[1]);
#endif
}

void
SelectInterruptor::handleProcessNotification()
{
   interrupt();
}

void
SelectInterruptor::buildFdSet(FdSet& fdset)
{
#ifdef WIN32
        fdset.setRead(mSocket);
#else
   fdset.setRead(mPipe[0]);
#endif
}

void
SelectInterruptor::processCleanup()
{
#ifdef WIN32
   {
      char rdBuf[16];
      recv(mSocket, rdBuf, sizeof(rdBuf), 0);
   }
#else
   {
      char rdBuf[16];
      int x;
      while ( (x=read(mPipe[0], rdBuf, sizeof(rdBuf))) == sizeof(rdBuf) )
         ;
      // WATCHOUT: EWOULDBLOCK *will* happen above when the pending
      // number of bytes is exactly size of rdBuf
      // XXX: should check for certain errors (like fd closed) and die?
   }
#endif
}

void
SelectInterruptor::process(FdSet& fdset)
{
   if (fdset.readyToRead(mReadThing))
      processCleanup();
}

void
SelectInterruptor::interrupt()
{
   static char wakeUp[] = "w";
#ifdef WIN32
   int count = send(mSocket, wakeUp, sizeof(wakeUp), 0);
   assert(count == sizeof(wakeUp));
#else
   ssize_t res = write(mPipe[1], wakeUp, sizeof(wakeUp));
   if ( res == -1 && errno==EAGAIN )
   {
      ; // this can happen when SipStack thread gets behind.
      // no need to block since our only purpose is to wake up the thread
      // also, this write can occur within the SipStack thread, in which
      // case we get dead-lock if this blocks
   } else {
      assert(res == sizeof(wakeUp));
   }
#endif
}

/* ====================================================================
 * The Vovida Software License, Version 1.0
 *
 * Copyright (c) 2000 Vovida Networks, Inc.  All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
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 *
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 *    distribution.
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 * vi: set shiftwidth=3 expandtab:
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