/*

 * Copyright 2006 Daniel Silverstone 

 * Copyright 2007 James Bursa 

 * Copyright 2003 Phil Mellor 

 *

 * This file is part of NetSurf.

 *

 * NetSurf 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; version 2 of the License.

 *

 * NetSurf 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 .

 */

/** \file

 * Fetching of data from a URL (implementation).

 *

 * This implementation uses libcurl's 'multi' interface.

 *

 *

 * The CURL handles are cached in the curl_handle_ring. There are at most

 * ::max_cached_fetch_handles in this ring.

 */

#include 

#include 

#include 

#include 

#include 

#include 

#include 

#include 

#include 

#include "utils/config.h"

//#include 

#include "content/fetch.h"

#include "content/fetchers/curl.h"

#include "content/urldb.h"

#include "desktop/netsurf.h"

#include "desktop/options.h"

#include "utils/log.h"

#include "utils/messages.h"

#include "utils/schedule.h"

#include "utils/utils.h"

#include "utils/ring.h"

#include "utils/useragent.h"

/* BIG FAT WARNING: This is here because curl doesn't give you an FD to

 * poll on, until it has processed a bit of the handle.	 So we need schedules

 * in order to make this work.

 */

#include 

/* uncomment this to use scheduler based calling

#define FETCHER_CURLL_SCHEDULED 1

*/

struct fetch_curl_context {

	struct fetch_curl_context *r_next, *r_prev;

	struct fetch *fetchh; /**< Handle for this fetch */

	bool aborted; /**< Flag indicating fetch has been aborted */

	bool locked; /**< Flag indicating entry is already entered */

	nsurl *url; /**< The full url the fetch refers to */

	char *path; /**< The actual path to be used with open() */

	time_t file_etag; /**< Request etag for file (previous st.m_time) */

};

static struct fetch_curl_context *ring = NULL;

static bool fetch_curl_initialise(lwc_string *scheme); //here

static void fetch_curl_finalise(lwc_string *scheme); //here

static bool fetch_curl_can_fetch(const nsurl *url); //here

static void * fetch_curl_setup(struct fetch *parent_fetch, nsurl *url,

		 bool only_2xx, bool downgrade_tls, const char *post_urlenc,

		 const struct fetch_multipart_data *post_multipart,

		 const char **headers); //here

static bool fetch_curl_start(void *vfetch); //here

static void fetch_curl_abort(void *vf); //here

static void fetch_curl_free(void *f); //here

static void fetch_curl_poll(lwc_string *scheme_ignored); //here

/**

 * Initialise the fetcher.

 *

 * Must be called once before any other function.

 */

void fetch_curl_register(void)

{

lwc_string *scheme;

LOG(("curl register\n"));

lwc_intern_string("http", SLEN("http"), &scheme);

	if (!fetch_add_fetcher(scheme,

				fetch_curl_initialise, //here

				fetch_curl_can_fetch, //here

				fetch_curl_setup,

				fetch_curl_start,

				fetch_curl_abort, //here

				fetch_curl_free, //here

#ifdef FETCHER_CURLL_SCHEDULED

				       NULL,

#else

				fetch_curl_poll, //here

#endif

				fetch_curl_finalise)) {  //here

			LOG(("Unable to register cURL fetcher for HTTP"));

		}

		lwc_intern_string("https", SLEN("https"), &scheme);

	if (!fetch_add_fetcher(scheme,

				fetch_curl_initialise,

				fetch_curl_can_fetch,

				fetch_curl_setup,

				fetch_curl_start,

				fetch_curl_abort,

				fetch_curl_free,

#ifdef FETCHER_CURLL_SCHEDULED

				       NULL,

#else

				fetch_curl_poll,

#endif

				fetch_curl_finalise)) {

			LOG(("Unable to register cURL fetcher for HTTPS"));

		}

}

/**

 * Initialise a cURL fetcher.

 */

bool fetch_curl_initialise(lwc_string *scheme)

{

LOG(("curl initi lwc\n"));

	return true; /* Always succeeds */

}

/**

 * Finalise a cURL fetcher

 */

void fetch_curl_finalise(lwc_string *scheme)

{

LOG(("curl finali\n"));

}

static bool fetch_curl_can_fetch(const nsurl *url)

{

	LOG(("curl can fetch\n"));

	return true; //let's lie a bit

}

/**

 * Start fetching data for the given URL.

 *

 * The function returns immediately. The fetch may be queued for later

 * processing.

 *

 * A pointer to an opaque struct curl_fetch_info is returned, which can be

 * passed to fetch_abort() to abort the fetch at any time. Returns 0 if memory

 * is exhausted (or some other fatal error occurred).

 *

 * The caller must supply a callback function which is called when anything

 * interesting happens. The callback function is first called with msg

 * FETCH_HEADER, with the header in data, then one or more times

 * with FETCH_DATA with some data for the url, and finally with

 * FETCH_FINISHED. Alternatively, FETCH_ERROR indicates an error occurred:

 * data contains an error message. FETCH_REDIRECT may replace the FETCH_HEADER,

 * FETCH_DATA, FETCH_FINISHED sequence if the server sends a replacement URL.

 *

 * Some private data can be passed as the last parameter to fetch_start, and

 * callbacks will contain this.

 */

void * fetch_curl_setup (struct fetch *fetchh,

		 nsurl *url,

		 bool only_2xx,

		 bool downgrade_tls,

		 const char *post_urlenc,

		 const struct fetch_multipart_data *post_multipart,

		 const char **headers)

{

	LOG(("curl setup\n"));

	struct fetch_curl_context *ctx;

	int i;

	ctx = calloc(1, sizeof(*ctx));

	if (ctx == NULL)

		return NULL;

	ctx->path = url_to_path(nsurl_access(url));

	if (ctx->path == NULL) {

		free(ctx);

		return NULL;

	}

	ctx->url = nsurl_ref(url);

	ctx->fetchh = fetchh;

	RING_INSERT(ring, ctx);

	return ctx;

}

/**

 * Dispatch a single job

 */

bool fetch_curl_start(void *vfetch)

{

LOG(("curl start\n"));

	return true;

}

/**

 * Abort a fetch.

 */

void fetch_curl_abort(void *ctx)

{

	struct fetch_curl_context *c = ctx;

	/* To avoid the poll loop having to deal with the fetch context

	 * disappearing from under it, we simply flag the abort here.

	 * The poll loop itself will perform the appropriate cleanup.

	 */

	c->aborted = true;

}

/**

 * Free a fetch structure and associated resources.

 */

void fetch_curl_free(void *ctx)

{

	struct fetch_curl_context *c = ctx;

	nsurl_unref(c->url);

	free(c->path);

	RING_REMOVE(ring, c);

	free(ctx);

}

static inline bool fetch_curl_send_callback(const fetch_msg *msg,

		struct fetch_curl_context *ctx)

{

	ctx->locked = true;

	fetch_send_callback(msg, ctx->fetchh);

	ctx->locked = false;

	return ctx->aborted;

}

static bool fetch_curl_send_header(struct fetch_curl_context *ctx,

		const char *fmt, ...)

{

	fetch_msg msg;

	char header[64];

	va_list ap;

	va_start(ap, fmt);

	vsnprintf(header, sizeof header, fmt, ap);

	va_end(ap);

	msg.type = FETCH_HEADER;

	msg.data.header_or_data.buf = (const uint8_t *) header;

	msg.data.header_or_data.len = strlen(header);

	fetch_curl_send_callback(&msg, ctx);

	return ctx->aborted;

}

static void fetch_curl_process_error(struct fetch_curl_context *ctx, int code)

{

	fetch_msg msg;

	char buffer[1024];

	const char *title;

	char key[8];

	/* content is going to return error code */

	fetch_set_http_code(ctx->fetchh, code);

	/* content type */

	if (fetch_curl_send_header(ctx, "Content-Type: text/html"))

		goto fetch_file_process_error_aborted;

	snprintf(key, sizeof key, "HTTP%03d", code);

	title = messages_get(key);

	snprintf(buffer, sizeof buffer, ""

			"
%s
"

			"
Error %d while fetching file %s
",

			title, title, code, nsurl_access(ctx->url));

	msg.type = FETCH_DATA;

	msg.data.header_or_data.buf = (const uint8_t *) buffer;

	msg.data.header_or_data.len = strlen(buffer);

	if (fetch_curl_send_callback(&msg, ctx))

		goto fetch_file_process_error_aborted;

	msg.type = FETCH_FINISHED;

	fetch_curl_send_callback(&msg, ctx);

fetch_file_process_error_aborted:

	return;

}

static void fetch_curl_process(struct fetch_curl_context *ctx) {

	fetch_msg msg;

	const char * buf = "
Hello, file fetcher!
";

//	fetch_curl_process_error(ctx, 501);

//	return;

/* fetch is going to be successful */

	fetch_set_http_code(ctx->fetchh, 200);

	/* Any callback can result in the fetch being aborted.

	 * Therefore, we _must_ check for this after _every_ call to

	 * fetch_file_send_callback().

	 */

	/* content type */

	if (fetch_curl_send_header(ctx, "Content-Type: text/html"))

		goto fetch_file_process_aborted;

	/* main data loop */

		msg.type = FETCH_DATA;

		msg.data.header_or_data.buf = (const uint8_t *) buf;

		msg.data.header_or_data.len = strlen(buf);

		fetch_curl_send_callback(&msg, ctx);

	if (ctx->aborted == false) {

		msg.type = FETCH_FINISHED;

		fetch_curl_send_callback(&msg, ctx);

	}

fetch_file_process_aborted:

return;

}

/**

 * Do some work on current fetches.

 *

 * Must be called regularly to make progress on fetches.

 */

void fetch_curl_poll(lwc_string *scheme_ignored)

{

	LOG(("curl poll\n"));

	struct fetch_curl_context *c, *next;

	if (ring == NULL) return;

	/* Iterate over ring, processing each pending fetch */

	c = ring;

	do {

		/* Ignore fetches that have been flagged as locked.

		 * This allows safe re-entrant calls to this function.

		 * Re-entrancy can occur if, as a result of a callback,

		 * the interested party causes fetch_poll() to be called

		 * again.

		 */

		if (c->locked == true) {

			next = c->r_next;

			continue;

		}

		/* Only process non-aborted fetches */

		if (c->aborted == false) {

			/* file fetches can be processed in one go */

			fetch_curl_process(c);

		}

		/* Compute next fetch item at the last possible moment as

		 * processing this item may have added to the ring.

		 */

		next = c->r_next;

		fetch_remove_from_queues(c->fetchh);

		fetch_free(c->fetchh);

		/* Advance to next ring entry, exiting if we've reached

		 * the start of the ring or the ring has become empty

		 */

	} while ( (c = next) != ring && ring != NULL);

}