Initial commit

common/rdr/FdOutStream.cxx

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+/* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright 2011 Pierre Ossman for Cendio AB
+ * Copyright 2017 Peter Astrand <astrand@cendio.se> for Cendio AB
+ * 
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#ifdef _WIN32
+#include <winsock2.h>
+#undef errno
+#define errno WSAGetLastError()
+#include <os/winerrno.h>
+#else
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#endif
+
+/* Old systems have select() in sys/time.h */
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
+#include <rdr/FdOutStream.h>
+#include <rdr/Exception.h>
+#include <rfb/util.h>
+
+
+using namespace rdr;
+
+enum { DEFAULT_BUF_SIZE = 16384 };
+
+FdOutStream::FdOutStream(int fd_, bool blocking_, int timeoutms_, int bufSize_)
+  : fd(fd_), blocking(blocking_), timeoutms(timeoutms_),
+    bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
+{
+  ptr = start = sentUpTo = new U8[bufSize];
+  end = start + bufSize;
+
+  gettimeofday(&lastWrite, NULL);
+}
+
+FdOutStream::~FdOutStream()
+{
+  try {
+    blocking = true;
+    flush();
+  } catch (Exception&) {
+  }
+  delete [] start;
+}
+
+void FdOutStream::setTimeout(int timeoutms_) {
+  timeoutms = timeoutms_;
+}
+
+void FdOutStream::setBlocking(bool blocking_) {
+  blocking = blocking_;
+}
+
+int FdOutStream::length()
+{
+  return offset + ptr - sentUpTo;
+}
+
+int FdOutStream::bufferUsage()
+{
+  return ptr - sentUpTo;
+}
+
+unsigned FdOutStream::getIdleTime()
+{
+  return rfb::msSince(&lastWrite);
+}
+
+void FdOutStream::flush()
+{
+  while (sentUpTo < ptr) {
+    int n = writeWithTimeout((const void*) sentUpTo,
+                             ptr - sentUpTo,
+                             blocking? timeoutms : 0);
+
+    // Timeout?
+    if (n == 0) {
+      // If non-blocking then we're done here
+      if (!blocking)
+        break;
+
+      throw TimedOut();
+    }
+
+    sentUpTo += n;
+    offset += n;
+  }
+
+   // Managed to flush everything?
+  if (sentUpTo == ptr)
+    ptr = sentUpTo = start;
+}
+
+
+int FdOutStream::overrun(int itemSize, int nItems)
+{
+  if (itemSize > bufSize)
+    throw Exception("FdOutStream overrun: max itemSize exceeded");
+
+  // First try to get rid of the data we have
+  flush();
+
+  // Still not enough space?
+  if (itemSize > end - ptr) {
+    // Can we shuffle things around?
+    // (don't do this if it gains us less than 25%)
+    if ((sentUpTo - start > bufSize / 4) &&
+        (itemSize < bufSize - (ptr - sentUpTo))) {
+      memmove(start, sentUpTo, ptr - sentUpTo);
+      ptr = start + (ptr - sentUpTo);
+      sentUpTo = start;
+    } else {
+      // Have to get rid of more data, so turn off non-blocking
+      // for a bit...
+      bool realBlocking;
+
+      realBlocking = blocking;
+      blocking = true;
+      flush();
+      blocking = realBlocking;
+    }
+  }
+
+  // Can we fit all the items asked for?
+  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 send() 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 send() returning EINTR.
+//
+
+int FdOutStream::writeWithTimeout(const void* data, int length, int timeoutms)
+{
+  int n;
+
+  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 = NULL;
+    }
+
+    FD_ZERO(&fds);
+    FD_SET(fd, &fds);
+    n = select(fd+1, 0, &fds, 0, tvp);
+  } while (n < 0 && errno == EINTR);
+
+  if (n < 0)
+    throw SystemException("select", errno);
+
+  if (n == 0)
+    return 0;
+
+  do {
+    // select only guarantees that you can write SO_SNDLOWAT without
+    // blocking, which is normally 1. Use MSG_DONTWAIT to avoid
+    // blocking, when possible.
+#ifndef MSG_DONTWAIT
+    n = ::send(fd, (const char*)data, length, 0);
+#else
+    n = ::send(fd, (const char*)data, length, MSG_DONTWAIT);
+#endif
+  } while (n < 0 && (errno == EINTR));
+
+  if (n < 0)
+    throw SystemException("write", errno);
+
+  gettimeofday(&lastWrite, NULL);
+
+  return n;
+}