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livetrax/libs/pbd/msvc/msvc_poll.cc

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/*
Copyright (C) 2009 John Emmas
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifdef COMPILER_MSVC
//#include <glib/gtimer.h>
#include "pbd/msvc_pbd.h"
#ifndef _DWORD_DEFINED
#define _DWORD_DEFINED
typedef unsigned long DWORD;
#endif // !_DWORD_DEFINED
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* Note that this entire strategy failed to work, at least for pipes. It turned *
* out that Windows 'tell()' always returns 0 when used on a pipe. This strategy *
* is now deprecated, having been replaced by a new pipe-like object, which I've *
* called 'PBD::pipex'. This polling functionality is included here mostly so *
* that Ardour will build and launch under Windows. However, any module that *
* relies on polling a pipe will eventually need to use the new pipex object. *
* This code will allow it to compile and link successfully, although it won't *
* poll successfully at run time. Having said that, these functions might well *
* work for ports and/or other machanisms that get represented by a file handle. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
int poll_input (struct pollfd *fds, nfds_t nfds, int& elapsed_time, int timeout)
{
DWORD dwOldTickCount,
dwNewTickCount = GetTickCount();
bool input = false,
error = false;
int ret = 0;
if (NULL != fds)
{
nfds_t loop;
short ev_mask = (POLLOUT|POLLWRNORM|POLLWRBAND);
errno = NO_ERROR;
do
{
dwOldTickCount = dwNewTickCount;
for (loop=0; loop<nfds; loop++)
fds[loop].revents = 0;
for (loop=0; (loop<nfds && !error); loop++)
{
if (!(fds[loop].events & ev_mask))
{
long pos = _tell(fds[loop].fd);
if (0 > pos)
{
// An error occured ('errno' should have been set by '_tell()')
ret = (-1);
fds[loop].revents = POLLERR;
if (fds[loop].events & POLLRDNORM)
fds[loop].revents |= POLLRDNORM;
if (fds[loop].events & POLLRDBAND)
fds[loop].revents |= POLLRDBAND;
if (fds[loop].events & POLLPRI)
fds[loop].revents |= POLLPRI;
// Do we want to abort on error?
if (fds[loop].events & POLLERR)
error = true;
}
else if (pos > 0)
{
// Input characters were found for this fd
ret += 1;
if (fds[loop].events & POLLRDNORM)
fds[loop].revents |= POLLRDNORM;
if (fds[loop].events & POLLRDBAND)
fds[loop].revents |= POLLRDBAND;
if (fds[loop].events & POLLPRI)
fds[loop].revents |= POLLPRI;
// Do we want to abort on input?
if ((fds[loop].events & POLLIN) ||
(fds[loop].events & POLLPRI) ||
(fds[loop].events & POLLRDNORM) ||
(fds[loop].events & POLLRDBAND))
input = true;
}
}
}
if (input)
break;
dwNewTickCount = GetTickCount();
elapsed_time += (dwNewTickCount-dwOldTickCount);
// Note that the above will wrap round if the user leaves
// his computer powered up for more than about 50 days!
// Sleep briefly because GetTickCount() only has an accuracy of 10mS
Sleep(10); // For some reason 'g_usleep()' craps over everything here. Different 'C' runtimes???
} while ((!error) && ((timeout == (-1)) || (elapsed_time < timeout)));
}
else
{
errno = ERROR_BAD_ARGUMENTS;
ret = (-1);
}
return (ret);
}
int poll_output (struct pollfd *fds, nfds_t nfds, int& elapsed_time, int timeout)
{
int ret = 0; // This functionality is not yet implemented
if (NULL != fds)
{
// Just flag whichever pollfd was specified for writing
short ev_mask = (POLLOUT|POLLWRNORM|POLLWRBAND);
errno = NO_ERROR;
elapsed_time = 0;
for (nfds_t loop=0; loop<nfds; loop++)
{
if (fds[loop].events & ev_mask)
{
fds[loop].revents = POLLNVAL;
errno = ERROR_INVALID_ACCESS;
ret = (-1);
}
}
}
else
{
errno = ERROR_BAD_ARGUMENTS;
ret = (-1);
}
return (ret);
}
//***************************************************************
//
// poll()
//
// Emulates POSIX poll() using Win32 _tell().
//
// Returns:
//
// On Success: A positive integer indicating the total number
// of file descriptors that were available for
// writing or had data available for reading.
// On Failure: -1 (the actual error is saved in 'errno').
//
LIBPBD_API int PBD_APICALLTYPE
poll (struct pollfd *fds, nfds_t nfds, int timeout)
{
int elapsed_time = 0;
int ret = (-1);
// Note that this functionality is not fully implemented.
// At the time of writing, Ardour seems only to poll on
// read pipes. Therefore return an error if any write
// pipe seems to have been specified or if too many file
// descriptors were passed.
short ev_mask = (POLLOUT|POLLWRNORM|POLLWRBAND);
if ((nfds > OPEN_MAX) || (nfds > NPOLLFILE))
{
errno = ERROR_TOO_MANY_OPEN_FILES;
}
else
{
ret = 0;
for (nfds_t loop=0; loop<nfds; loop++)
{
if (fds[loop].events & ev_mask)
{
ret = poll_output(fds, nfds, elapsed_time, timeout);
break;
}
}
if (0 == ret)
{
// Poll for input
ret = poll_input(fds, nfds, elapsed_time, timeout);
}
}
return (ret);
}
#endif //COMPILER_MSVC