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transmission/libtransmission/iobuf.c
2008-11-26 02:57:32 +00:00

378 lines
9.1 KiB
C

/*
* Copyright (c) 2002-2004 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* Transmission modifications and new bugs by Charles Kerr.
* Source: libevent's "patches-1.4" branch, svn revision 949
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> /* write */
#include "evutil.h"
#include "event.h"
#include "transmission.h"
#include "bandwidth.h"
#include "iobuf.h"
#include "session.h"
#include "utils.h"
#define MAGIC_NUMBER 235705
struct tr_iobuf
{
struct event_base * ev_base;
struct event ev_read;
struct event ev_write;
struct evbuffer * input;
struct evbuffer * output;
tr_iobuf_cb readcb;
tr_iobuf_cb writecb;
tr_iobuf_error_cb errorcb;
void * cbarg;
int magicNumber;
int timeout_read; /* in seconds */
int timeout_write; /* in seconds */
short enabled; /* events that are currently enabled */
struct tr_handle * session;
struct tr_bandwidth * bandwidth;
};
/***
****
***/
static int
isBuf( const struct tr_iobuf * iobuf )
{
return ( iobuf != NULL ) && ( iobuf->magicNumber == MAGIC_NUMBER );
}
static int
tr_evbuffer_write( struct evbuffer *buffer, int fd, size_t maxlen )
{
int n = MIN( EVBUFFER_LENGTH( buffer ), maxlen );
#ifdef WIN32
n = send(fd, buffer->buffer, n, 0 );
#else
n = write(fd, buffer->buffer, n );
#endif
if( n == -1 )
return -1;
if (n == 0)
return 0;
evbuffer_drain( buffer, n );
return n;
}
static int
tr_iobuf_add(struct event *ev, int timeout)
{
struct timeval tv, *ptv = NULL;
if (timeout) {
evutil_timerclear(&tv);
tv.tv_sec = timeout;
ptv = &tv;
}
return event_add( ev, ptv );
}
static void
tr_iobuf_readcb( int fd, short event, void * arg )
{
int res;
short what = EVBUFFER_READ;
struct tr_iobuf * b = arg;
const size_t howmuch = tr_bandwidthClamp( b->bandwidth, TR_DOWN, b->session->so_rcvbuf );
assert( isBuf( b ) );
if( event == EV_TIMEOUT ) {
what |= EVBUFFER_TIMEOUT;
goto error;
}
/* if we don't have any bandwidth left, stop reading */
if( howmuch < 1 ) {
event_del( &b->ev_read );
return;
}
res = evbuffer_read( b->input, fd, howmuch );
if( res == -1 ) {
if( errno == EAGAIN || errno == EINTR )
goto reschedule;
/* error case */
what |= EVBUFFER_ERROR;
} else if( res == 0 ) {
/* eof case */
what |= EVBUFFER_EOF;
}
if( res <= 0 )
goto error;
tr_iobuf_add( &b->ev_read, b->timeout_read );
/* Invoke the user callback - must always be called last */
if( b->readcb != NULL )
( *b->readcb )( b, res, b->cbarg );
return;
reschedule:
tr_iobuf_add( &b->ev_read, b->timeout_read );
return;
error:
(*b->errorcb)( b, what, b->cbarg );
}
static void
tr_iobuf_writecb( int fd, short event, void * arg )
{
int res = 0;
short what = EVBUFFER_WRITE;
struct tr_iobuf * b = arg;
size_t howmuch;
assert( isBuf( b ) );
if( event == EV_TIMEOUT ) {
what |= EVBUFFER_TIMEOUT;
goto error;
}
howmuch = MIN( (size_t)b->session->so_sndbuf, EVBUFFER_LENGTH( b->output ) );
howmuch = tr_bandwidthClamp( b->bandwidth, TR_UP, howmuch );
/* if we don't have any bandwidth left, stop writing */
if( howmuch < 1 ) {
event_del( &b->ev_write );
return;
}
res = tr_evbuffer_write( b->output, fd, howmuch );
if (res == -1) {
#ifndef WIN32
/*todo. evbuffer uses WriteFile when WIN32 is set. WIN32 system calls do not
*set errno. thus this error checking is not portable*/
if (errno == EAGAIN || errno == EINTR || errno == EINPROGRESS)
goto reschedule;
/* error case */
what |= EVBUFFER_ERROR;
#else
goto reschedule;
#endif
} else if (res == 0) {
/* eof case */
what |= EVBUFFER_EOF;
}
if (res <= 0)
goto error;
if( EVBUFFER_LENGTH( b->output ) )
tr_iobuf_add( &b->ev_write, b->timeout_write );
if( b->writecb != NULL )
(*b->writecb)( b, res, b->cbarg );
return;
reschedule:
if( EVBUFFER_LENGTH( b->output ) )
tr_iobuf_add( &b->ev_write, b->timeout_write );
return;
error:
(*b->errorcb)( b, what, b->cbarg );
}
/*
* Create a new buffered event object.
*
* The read callback is invoked whenever we read new data.
* The write callback is invoked whenever the output buffer is drained.
* The error callback is invoked on a write/read error or on EOF.
*
* Both read and write callbacks maybe NULL. The error callback is not
* allowed to be NULL and have to be provided always.
*/
struct tr_iobuf *
tr_iobuf_new( struct tr_handle * session,
tr_bandwidth * bandwidth,
int fd,
short event,
tr_iobuf_cb readcb,
tr_iobuf_cb writecb,
tr_iobuf_error_cb errorcb,
void * cbarg )
{
struct tr_iobuf * b;
b = tr_new0( struct tr_iobuf, 1 );
b->magicNumber = MAGIC_NUMBER;
b->session = session;
b->bandwidth = bandwidth;
b->input = evbuffer_new( );
b->output = evbuffer_new( );
event_set( &b->ev_read, fd, EV_READ, tr_iobuf_readcb, b );
event_set( &b->ev_write, fd, EV_WRITE, tr_iobuf_writecb, b );
tr_iobuf_setcb( b, readcb, writecb, errorcb, cbarg );
tr_iobuf_enable( b, event );
return b;
}
void
tr_iobuf_setcb( struct tr_iobuf * b,
tr_iobuf_cb readcb,
tr_iobuf_cb writecb,
tr_iobuf_error_cb errorcb,
void * cbarg )
{
assert( isBuf( b ) );
b->readcb = readcb;
b->writecb = writecb;
b->errorcb = errorcb;
b->cbarg = cbarg;
}
/* Closing the file descriptor is the responsibility of the caller */
void
tr_iobuf_free( struct tr_iobuf * b )
{
assert( isBuf( b ) );
b->magicNumber = 0xDEAD;
event_del( &b->ev_read );
event_del( &b->ev_write );
evbuffer_free( b->input );
evbuffer_free( b->output );
tr_free( b );
}
int
tr_iobuf_enable(struct tr_iobuf * b, short event )
{
assert( isBuf( b ) );
if( event & EV_READ )
if( tr_iobuf_add( &b->ev_read, b->timeout_read ) == -1 )
return -1;
if( event & EV_WRITE )
if ( tr_iobuf_add( &b->ev_write, b->timeout_write ) == -1 )
return -1;
b->enabled |= event;
return 0;
}
int
tr_iobuf_disable( struct tr_iobuf * b, short event )
{
assert( isBuf( b ) );
if( event & EV_READ )
if( event_del( &b->ev_read ) == -1 )
return -1;
if( event & EV_WRITE )
if( event_del( &b->ev_write ) == -1 )
return -1;
b->enabled &= ~event;
return 0;
}
void
tr_iobuf_settimeout( struct tr_iobuf * b,
int timeout_read,
int timeout_write )
{
assert( isBuf( b ) );
b->timeout_read = timeout_read;
if( event_pending( &b->ev_read, EV_READ, NULL ) )
tr_iobuf_add( &b->ev_read, timeout_read );
b->timeout_write = timeout_write;
if( event_pending( &b->ev_write, EV_WRITE, NULL ) )
tr_iobuf_add( &b->ev_write, timeout_write );
}
void
tr_iobuf_set_bandwidth( struct tr_iobuf * b,
struct tr_bandwidth * bandwidth )
{
assert( isBuf( b ) );
b->bandwidth = bandwidth;
}
struct evbuffer*
tr_iobuf_input( struct tr_iobuf * b )
{
assert( isBuf( b ) );
return b->input;
}
struct evbuffer*
tr_iobuf_output( struct tr_iobuf * b )
{
assert( isBuf( b ) );
return b->output;
}