barrier/src/vnc/common/rdr/FdOutStream.cxx

175 lines
4.2 KiB
C++

/* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
*
* This 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 software 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 software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
#include <stdio.h>
#include <string.h>
#ifdef _WIN32
#include <winsock2.h>
#define write(s,b,l) send(s,(const char*)b,l,0)
#define EWOULDBLOCK WSAEWOULDBLOCK
#undef errno
#define errno WSAGetLastError()
#undef EINTR
#define EINTR WSAEINTR
#else
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <sys/time.h>
#endif
#include <rdr/FdOutStream.h>
#include <rdr/Exception.h>
using namespace rdr;
enum { DEFAULT_BUF_SIZE = 16384,
MIN_BULK_SIZE = 1024 };
FdOutStream::FdOutStream(int fd_, int timeoutms_, int bufSize_)
: fd(fd_), timeoutms(timeoutms_),
bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
{
ptr = start = new U8[bufSize];
end = start + bufSize;
}
FdOutStream::~FdOutStream()
{
try {
flush();
} catch (Exception&) {
}
delete [] start;
}
void FdOutStream::setTimeout(int timeoutms_) {
timeoutms = timeoutms_;
}
void FdOutStream::writeBytes(const void* data, int length)
{
if (length < MIN_BULK_SIZE) {
OutStream::writeBytes(data, length);
return;
}
const U8* dataPtr = (const U8*)data;
flush();
while (length > 0) {
int n = writeWithTimeout(dataPtr, length);
length -= n;
dataPtr += n;
offset += n;
}
}
int FdOutStream::length()
{
return offset + ptr - start;
}
void FdOutStream::flush()
{
U8* sentUpTo = start;
while (sentUpTo < ptr) {
int n = writeWithTimeout((const void*) sentUpTo, ptr - sentUpTo);
sentUpTo += n;
offset += n;
}
ptr = start;
}
int FdOutStream::overrun(int itemSize, int nItems)
{
if (itemSize > bufSize)
throw Exception("FdOutStream overrun: max itemSize exceeded");
flush();
if (itemSize * nItems > end - ptr)
nItems = (end - ptr) / itemSize;
return nItems;
}
//
// writeWithTimeout() writes up to the given length in bytes from the given
// buffer to the file descriptor. If there is a timeout set and that timeout
// expires, it throws a TimedOut exception. Otherwise it returns the number of
// bytes written. It never attempts to write() unless select() indicates that
// the fd is writable - this means it can be used on an fd which has been set
// non-blocking. It also has to cope with the annoying possibility of both
// select() and write() returning EINTR.
//
int FdOutStream::writeWithTimeout(const void* data, int length)
{
int n;
do {
do {
fd_set fds;
struct timeval tv;
struct timeval* tvp = &tv;
if (timeoutms != -1) {
tv.tv_sec = timeoutms / 1000;
tv.tv_usec = (timeoutms % 1000) * 1000;
} else {
tvp = 0;
}
FD_ZERO(&fds);
FD_SET(fd, &fds);
#ifdef _WIN32_WCE
// NB: This fixes a broken Winsock2 select() behaviour. select()
// never returns for non-blocking sockets, unless they're already
// ready to be written to...
u_long zero = 0; ioctlsocket(fd, FIONBIO, &zero);
#endif
n = select(fd+1, 0, &fds, 0, tvp);
#ifdef _WIN32_WCE
u_long one = 0; ioctlsocket(fd, FIONBIO, &one);
#endif
} while (n < 0 && errno == EINTR);
if (n < 0) throw SystemException("select",errno);
if (n == 0) throw TimedOut();
do {
n = ::write(fd, data, length);
} while (n < 0 && (errno == EINTR));
// NB: This outer loop simply fixes a broken Winsock2 EWOULDBLOCK
// condition, found only under Win98 (first edition), with slow
// network connections. Should in fact never ever happen...
} while (n < 0 && (errno == EWOULDBLOCK));
if (n < 0) throw SystemException("write",errno);
return n;
}