clib package
This commit is contained in:
Vítor Santos Costa
290
packages/clib/winpipe.c
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290
packages/clib/winpipe.c
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/* $Id$
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Part of SWI-Prolog
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Author: Jan Wielemaker
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E-mail: jan@swi.psy.uva.nl
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WWW: http://www.swi-prolog.org
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Copyright (C): 1985-2004, University of Amsterdam
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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As a special exception, if you link this library with other files,
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compiled with a Free Software compiler, to produce an executable, this
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library does not by itself cause the resulting executable to be covered
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by the GNU General Public License. This exception does not however
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invalidate any other reasons why the executable file might be covered by
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the GNU General Public License.
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*/
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#include <SWI-Stream.h>
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#include <SWI-Prolog.h>
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#include <errno.h>
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#ifdef __WINDOWS__
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#include <windows.h>
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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This file provides a windows alternative to an anonymous pipe that can
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be waited for in the same pool as sockets using by tcp_select/3. It is a
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work-around that allows a socket-based server using tcp_select/3 for IO
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multiplexing to create an additional communication channal for
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controlling the server.
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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#define PIPE_MAGIC 0x6b3a914cL
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#define ISPIPE(p) if ( p->magic != PIPE_MAGIC ) \
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{ errno = EINVAL; \
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return -1; \
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}
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typedef struct pipe
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{ long magic; /* magic code */
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int size; /* size of the pipe */
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char *buf; /* Buffer */
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int in;
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int out;
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int writers; /* write open count */
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int readers; /* read open count */
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int blocking; /* pipe is blocking */
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CRITICAL_SECTION mutex;
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HANDLE event; /* signal if data is available */
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} pipe;
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static pipe *
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create_pipe(int size, int blocking)
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{ pipe *p = PL_malloc(sizeof(*p));
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p->buf = PL_malloc(size);
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p->size = size;
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p->in = p->out = 0;
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p->readers = p->writers = 0;
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p->blocking = blocking;
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InitializeCriticalSection(&p->mutex);
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p->event = CreateEvent(NULL, FALSE, FALSE, NULL);
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p->magic = PIPE_MAGIC;
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return p;
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}
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static int
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destroy_pipe(pipe *p)
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{ ISPIPE(p);
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EnterCriticalSection(&p->mutex);
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PL_free(p->buf);
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CloseHandle(p->event);
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LeaveCriticalSection(&p->mutex);
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DeleteCriticalSection(&p->mutex);
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p->magic = 0;
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PL_free(p);
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return 0;
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}
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static int
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write_pipe(pipe *pipe, char *buf, int size)
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{ ISPIPE(pipe);
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EnterCriticalSection(&pipe->mutex);
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for(;;)
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{ if ( pipe->in + size <= pipe->size )
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{ memcpy(pipe->buf+pipe->in, buf, size);
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pipe->in += size;
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SetEvent(pipe->event);
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LeaveCriticalSection(&pipe->mutex);
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return size;
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}
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if ( pipe->out > 0 )
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{ memmove(pipe->buf, pipe->buf+pipe->out, pipe->in - pipe->out);
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pipe->in -= pipe->out;
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pipe->out = 0;
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}
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if ( size > pipe->size )
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size = pipe->size;
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}
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}
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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Non-blocking read from our pipe.
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- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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static int
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read_pipe(pipe *pipe, char *buf, int size)
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{ int avail;
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ISPIPE(pipe);
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retry:
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EnterCriticalSection(&pipe->mutex);
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avail = pipe->in - pipe->out;
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if ( avail > 0 )
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{ if ( size < avail )
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avail = size;
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memcpy(buf, pipe->buf+pipe->out, avail);
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pipe->out += avail;
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if ( pipe->in == pipe->out )
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pipe->in = pipe->out = 0;
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LeaveCriticalSection(&pipe->mutex);
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return avail;
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}
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if ( pipe->writers == 0 )
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{ LeaveCriticalSection(&pipe->mutex);
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return 0;
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}
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if ( pipe->blocking )
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{ int rc;
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LeaveCriticalSection(&pipe->mutex);
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rc = MsgWaitForMultipleObjects(1,
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&pipe->event,
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FALSE, /* wait for either event */
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INFINITE,
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QS_ALLINPUT);
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if ( rc == WAIT_OBJECT_0+1 ) /* message arrived */
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{ MSG msg;
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while( PeekMessage(&msg, NULL, 0, 0, PM_REMOVE) )
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{ TranslateMessage(&msg);
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DispatchMessage(&msg);
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if ( PL_handle_signals() < 0 )
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{ errno = EINTR; /* exception */
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return -1;
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}
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}
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}
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goto retry;
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}
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errno = EWOULDBLOCK;
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LeaveCriticalSection(&pipe->mutex);
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return -1;
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}
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static int
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reader_close_pipe(pipe *p)
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{ ISPIPE(p);
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p->readers--;
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if ( p->readers <= 0 && p->writers <= 0 )
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return destroy_pipe(p);
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return 0;
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}
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static int
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writer_close_pipe(pipe *p)
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{ ISPIPE(p);
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p->writers--;
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if ( p->readers <= 0 && p->writers <= 0 )
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return destroy_pipe(p);
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if ( p->writers <= 0 )
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{ SetEvent(p->event); /* Signal EOF */
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}
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return 0;
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}
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static IOFUNCTIONS pipe_read_functions =
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{ (Sread_function) read_pipe,
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(Swrite_function) write_pipe,
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(Sseek_function) 0,
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(Sclose_function) reader_close_pipe,
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(Scontrol_function) 0
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};
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static IOFUNCTIONS pipe_write_functions =
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{ (Sread_function) read_pipe,
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(Swrite_function) write_pipe,
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(Sseek_function) 0,
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(Sclose_function) writer_close_pipe,
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(Scontrol_function) 0
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};
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static foreign_t
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tcp_pipe(term_t in, term_t out)
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{ pipe *p = create_pipe(4096, TRUE);
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IOSTREAM *sin, *sout;
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sin = Snew(p, SIO_FBUF|SIO_INPUT|SIO_RECORDPOS, &pipe_read_functions);
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p->readers++;
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sout = Snew(p, SIO_FBUF|SIO_OUTPUT|SIO_RECORDPOS, &pipe_write_functions);
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p->writers++;
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if ( !PL_unify_stream(in, sin) ||
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!PL_unify_stream(out, sout) )
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{ Sclose(sin);
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Sclose(sout);
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return FALSE;
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}
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return TRUE;
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}
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#else /*__WINDOWS__*/
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static foreign_t
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tcp_pipe(term_t Read, term_t Write)
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{ int fd[2];
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IOSTREAM *in, *out;
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if ( pipe(fd) != 0 )
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return pl_error("pipe", 2, NULL, ERR_ERRNO, errno, "create", "pipe", 0);
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in = Sfdopen(fd[0], "r");
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out = Sfdopen(fd[1], "w");
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if ( PL_unify_stream(Read, in) &&
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PL_unify_stream(Write, out) )
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return TRUE;
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Sclose(in);
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Sclose(out);
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return FALSE;
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}
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#endif /*__WINDOWS__*/
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install_t
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install_winpipe()
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{ PL_register_foreign("tcp_pipe", 2, tcp_pipe, 0);
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}
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