taskrambler/src/http/writer/write.c

/**
 * \file
 *
 * \author	Georg Hopp
 *
 * \copyright
 * Copyright © 2012  Georg Hopp
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <unistd.h>
#include <sys/stat.h>

#include "class.h"
#include "http/message.h"
#include "queue.h"
#include "http/writer.h"
#include "stream.h"

#include "commons.h"
#include "utils/memory.h"


ssize_t
httpWriterWrite(void * _this, Stream st)
{
	HttpWriter this = _this;
	int        cont = 1;

	while (cont) {
		switch (this->state) {
			char    * start;
			ssize_t   to_write;
			ssize_t   written;

			case HTTP_WRITER_GET:
				if (! queueEmpty(this->queue)) {
					this->current = queueGet(this->queue);

					this->written = 0;
					this->nheader = httpMessageHeaderSizeGet(this->current);

					if (this->nheader > memGetSize(this->buffer)) {
						ssize_t size = this->nheader;

						size = (0 != size%WRITER_BUF_CHUNK)?
							(size/WRITER_BUF_CHUNK)+1 :
							size/WRITER_BUF_CHUNK;
						size *= WRITER_BUF_CHUNK;

						if (NULL != this->buffer) {
							MEM_FREE(this->buffer);
						}

						this->buffer  = memMalloc(size);
						this->nbuffer = size;
					}

					httpMessageHeaderToString(this->current, this->buffer);

					this->nbody = MIN(
							this->current->nbody,
							this->nbuffer - this->nheader);

					memcpy(
							this->buffer + this->nheader,
							this->current->body,
							this->nbody);

					this->state = HTTP_WRITER_WRITE;
				}
				else {
					cont = 0;
					break;
				}

			case HTTP_WRITER_WRITE:
				if (this->written >= this->nbuffer) {
					size_t body_done = this->written - this->nheader;

					start    = this->current->body + body_done;
					to_write = this->current->nbody - body_done;
				} else {
					start    = this->buffer   + this->written;
					to_write = (this->nheader + this->nbody) - this->written;
				}

				written = streamWrite(st, start, to_write);

				if (written < 0) {
					return written;
				}

				this->written += written;

				if (written != to_write) {
					/*
					 * for some reason not all data could be
					 * written...most likely its a slow connection
					 * so, not to slow down the server we stop
					 * writing to this one now and come back to
					 * it in the next run....maybe it would be
					 * feasable to also implement some kind of
					 * timeout mechanism for writes...
					 * By the way, the same is true for reading,
					 * so to say, the parser.
					 */
					cont = 0;
					break;
				}

				if (this->written >= this->nheader + this->current->nbody) {
					// we are done with this message.
					this->state = HTTP_WRITER_DONE;
				} else {
					break;
				}

			case HTTP_WRITER_DONE:
	 			this->state = HTTP_WRITER_GET;

				if (! httpMessageHasKeepAlive(this->current)) {
					/**
					 * if the message did not have the keep-alive feature
					 * we don't care about further pipelined messages and
					 * return to the caller with a -2 indicating that the
					 * underlying connection should be closed at their side.
					 * Then we close to connection.
					 */
					return -2;
				}
				delete(this->current);

				break;
		}
	}

	return NULL == this->current ?
		this->queue->nmsg :
		this->queue->nmsg + 1;
}

// vim: set ts=4 sw=4: