// return 1 if chain has been fully sent, 0 otherwise
int
processChain(
BufferedWriter* self,
BufferChain* chain
) {
uint8_t* buf = mbuf_rdptr(chain->mbuf);
size_t size = mbuf_message_offset(chain->mbuf) - mbuf_read_offset(chain->mbuf);
size_t sent = 0;
chain->reading = 1;
oml_unlock(&self->lock, "processChain"); /* don't keep lock while transmitting */
MBuffer* meta = self->meta_buf;
while (size > sent) {
long cnt = self->writeFunc(self->writeFuncHdl, (void*)(buf + sent), size - sent,
meta->rdptr, meta->fill);
if (cnt > 0) {
sent += cnt;
} else {
/* ERROR: Sleep a bit and try again */
/* To be on the safe side, we rewind to the beginning of the
* chain and try to resend everything - this is especially important
* if the underlying stream needs to reopen and resync.
*/
mbuf_reset_read(chain->mbuf);
size = mbuf_message_offset(chain->mbuf) - mbuf_read_offset(chain->mbuf);
sent = 0;
sleep(1);
}
}
// get lock back to see what happened while we were busy
oml_lock_persistent(self);
mbuf_read_skip(chain->mbuf, sent);
if (mbuf_write_offset(chain->mbuf) == mbuf_read_offset(chain->mbuf)) {
// seem to have sent everything so far, reset chain
// mbuf_clear2(chain->mbuf, 0);
mbuf_clear2(chain->mbuf, 1);
chain->reading = 0;
return 1;
}
return 0;
}
/** Send data contained in one chunk.
*
* \warning This function acquires the lock on the BufferedWriter for the time
* it takes to check the double-buffer.
*
* \warning This function acquires the lock on the chunk being processed for
* the time it takes to check it and swap the double buffer.
*
* \bug The meta buffer should also be protected.
*
* \param self BufferedWriter to process
* \param chunk link of the chunk to process
*
* \return 1 if chunk has been fully sent, 0 if not, -1 on continuing back-off, -2 otherwise
* \see oml_outs_write_f
*/
static int
processChunk(BufferedWriter* self, BufferChunk* chunk)
{
time_t now;
int ret = -2;
ssize_t cnt = 0;
MBuffer *read_buf = NULL;
assert(self);
assert(self->meta_buf);
assert(self->read_buf);
assert(chunk);
assert(chunk->mbuf);
oml_lock(&self->lock, __FUNCTION__);
if (mbuf_message(self->read_buf) > mbuf_rdptr(self->read_buf)) {
/* There is unread data in the double buffer */
read_buf = self->read_buf;
}
oml_unlock(&self->lock, __FUNCTION__);
oml_lock(&chunk->lock, __FUNCTION__);
if ((NULL == read_buf) && (mbuf_message(chunk->mbuf) >= mbuf_rdptr(chunk->mbuf))) {
/* There is unread data in the read buffer, swap MBuffers */
read_buf = chunk->mbuf;
chunk->mbuf = self->read_buf;
}
oml_unlock(&chunk->lock, __FUNCTION__);
oml_lock(&self->lock, __FUNCTION__);
self->read_buf = read_buf;
oml_unlock(&self->lock, __FUNCTION__);
if (NULL == read_buf) {
/* The current message is not after the read pointer,
* we must be on the writer chunk */
ret = 1;
goto processChunk_cleanup;
}
time(&now);
if (difftime(now, self->last_failure_time) < self->backoff) {
logdebug("%s: Still in back-off period (%ds)\n", self->outStream->dest, self->backoff);
ret = -1;
goto processChunk_cleanup;
}
while (mbuf_write_offset(read_buf) > mbuf_read_offset(read_buf)) {
oml_lock(&self->meta_lock, __FUNCTION__);
cnt = self->outStream->write(self->outStream,
mbuf_rdptr(read_buf), mbuf_message_offset(read_buf) - mbuf_read_offset(read_buf),
mbuf_rdptr(self->meta_buf), mbuf_fill(self->meta_buf));
oml_unlock(&self->meta_lock, __FUNCTION__);
if (cnt > 0) {
mbuf_read_skip(read_buf, cnt);
if (self->backoff) {
self->backoff = 0;
loginfo("%s: Connected\n", self->outStream->dest);
}
} else {
self->last_failure_time = now;
if (!self->backoff) {
self->backoff = 1;
} else if (self->backoff < UINT8_MAX) {
self->backoff *= 2;
}
logwarn("%s: Error sending, backing off for %ds\n", self->outStream->dest, self->backoff);
goto processChunk_cleanup;
}
}
ret = 1;
processChunk_cleanup:
return ret;
}