// Helper method to send a number of bytes over fd. Returns the
// number of bytes that failed to send.
int
stream_handler::send_data(const char * buf, size_t length) {
int bytes_written = write(fd, buf, length);
if(bytes_written == -1) {
if(errno == EAGAIN) {
tracer.trace5( "EAGAIN when trying to write %zu bytes to fd%d", length, fd);
// The file descriptor is backed up! Try again when it
// becomes writeable in the future.
watch_writable(fd, true);
return length;
}
if(errno == ECONNRESET) {
// Connection closed by the other side while we were
// busy getting through our buf_.
tracer.trace0( "Connection closed when trying to write %zu bytes to fd%d",
length, fd);
on_connection_closed();
watch_stream(fd, false);
return 0;
}
tracer.trace0( "Unexpected error code from send(): %d", errno);
assert("send unexpectedly failed");
} else if((size_t) bytes_written < length) {
watch_writable(fd, true);
} else {
// The fd is sending all data, no need to get alerts on when
// it is writable.
watch_writable(fd, false);
}
tracer.trace8("Sent %d of %zu bytes", bytes_written, length);
return length - bytes_written;
}
void SessionHandler::WatchStream(int socketDescriptor, bool doWatch)
{
assert((m_fd != 0 && m_fd != socketDescriptor) == false); // only one stream for a socket
if (doWatch)
{
m_tracer.trace0("watching socket %d", socketDescriptor);
m_fd = socketDescriptor;
watch_readable(m_fd, true);
m_readBuffer = new char[m_bufferSize];
m_writeBuffer = new char[m_bufferSize];
m_bytesRead = 0;
m_bytesToWrite = 0;
OnConnect();
}
else if (m_fd != 0)
{
m_tracer.trace0("cleaning up");
watch_readable(m_fd, false);
watch_writable(m_fd, false);
delete [] m_readBuffer;
delete [] m_writeBuffer;
m_readBuffer = nullptr;
m_writeBuffer = nullptr;
m_fd = 0;
m_nextMessageLength = 0;
}
}
void
stream_handler::watch_stream(int file_descriptor, bool should_watch) {
if(fd && fd != file_descriptor) {
assert(!"Only allowed to handle one stream at a time");
}
if(!should_watch) {
if(fd) {
tracer.trace0("Cleaning up");
watch_readable(fd, false);
watch_writable(fd, false);
delete[] read_buf;
delete[] write_buf;
read_buf = NULL;
write_buf = NULL;
fd = 0;
next_message_length = 0;
delimiter = NULL;
delimiter_length = 0;
}
} else {
tracer.trace0("Watching stream %d", file_descriptor);
fd = file_descriptor;
watch_readable(fd, true);
read_buf = new char[buf_size];
write_buf = new char[buf_size];
bytes_read = 0;
bytes_to_write = 0;
}
}
int SessionHandler::SendData(const char* buffer, size_t length)
{
auto bytesWritten = write(m_fd, buffer, length);
if (bytesWritten == -1)
{
switch (errno)
{
case EAGAIN:
m_tracer.trace5("EAGAIN when trying %d bytes to socket %d", length, m_fd);
watch_writable(m_fd, true);
return length;
case ECONNRESET:
m_tracer.trace0("connection closed while trying to write %d bytes to %d",
length, m_fd);
OnConnectionClosed();
WatchStream(m_fd, false);
return 0;
default:
m_tracer.trace0("unexpected error code from send(): %d", errno);
break;
}
}
else if ((size_t)bytesWritten < length)
{
watch_writable(m_fd, true);
}
else
{
watch_writable(m_fd, false);
}
return length - bytesWritten;
}
void
stream_handler::on_writable(int notifying_fd) {
if(notifying_fd != fd) {
return;
}
if(!bytes_to_write) {
// If we somehow get called but have nothing to write,
// unregister our interest in this notification.
watch_writable(fd, false);
return;
}
tracer.trace7("Buffer is writable, attempting to send %zu bytes",
bytes_to_write);
int bytes_remaining = send_data(write_buf, bytes_to_write);
if(bytes_remaining) {
memmove(write_buf, write_buf + bytes_to_write - bytes_remaining,
bytes_remaining);
}
bytes_to_write = bytes_remaining;
}
void SessionHandler::on_writable(int notifyingSocket)
{
if (notifyingSocket != m_fd)
{
return;
}
if (m_bytesToWrite == 0)
{
watch_writable(m_fd, false);
return;
}
m_tracer.trace7("Buffer is writable, attempting to send %d bytes", m_bytesToWrite);
auto bytesRemaining = SendData(m_writeBuffer, m_bytesToWrite);
if(bytesRemaining)
{
memmove(m_writeBuffer, m_writeBuffer + m_bytesToWrite - bytesRemaining, bytesRemaining);
}
m_bytesToWrite = bytesRemaining;
}