Add a redirecting fetcher for the doi: URI scheme. Not much used but just in case...

svn path=/trunk/netsurf/; revision=12412

Makefile.sources

@@ -7,7 +7,7 @@
 S_CONTENT := content.c content_factory.c dirlist.c fetch.c hlcache.c	\
 	llcache.c urldb.c
 
-S_FETCHERS := curl.c data.c file.c about.c resource.c
+S_FETCHERS := curl.c data.c doi.c file.c about.c resource.c
 
 S_CSS := css.c dump.c internal.c select.c utils.c
 

content/fetch.c

@@ -42,6 +42,7 @@
 #include "content/fetchers/about.h"
 #include "content/fetchers/curl.h"
 #include "content/fetchers/data.h"
+#include "content/fetchers/doi.h"
 #include "content/fetchers/file.h"
 #include "content/urldb.h"
 #include "desktop/netsurf.h"
@@ -112,6 +113,7 @@ void fetch_init(void)
 {
 	fetch_curl_register();
 	fetch_data_register();
+	fetch_doi_register();
 	fetch_file_register();
 	fetch_resource_register();
 	fetch_about_register();

content/fetchers/doi.c

@@ -0,0 +1,207 @@
+/*
+ * Copyright 2011 François Revol <mmu_man@users.sourceforge.net>
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+/* doi: URL handling. Based on the resource fetcher by Vincent Sanders */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <string.h>
+#include <strings.h>
+#include <time.h>
+#include <stdio.h>
+#include <dirent.h>
+#include <limits.h>
+#include <stdarg.h>
+
+#include "utils/config.h"
+#include "content/dirlist.h"
+#include "content/fetch.h"
+#include "content/fetchers/doi.h"
+#include "content/urldb.h"
+#include "desktop/netsurf.h"
+#include "desktop/options.h"
+#include "utils/log.h"
+#include "utils/messages.h"
+#include "utils/url.h"
+#include "utils/utils.h"
+#include "utils/ring.h"
+
+struct fetch_doi_context;
+
+/** Context for an resource fetch */
+struct fetch_doi_context {
+	struct fetch_doi_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 */
+
+	char redirect_url[1]; /**< The url the fetch redirects to */
+};
+
+static struct fetch_doi_context *ring = NULL;
+
+static const char *fetch_doi_redirect_base = "http://dx.doi.org/";
+
+/** issue fetch callbacks with locking */
+static inline bool fetch_doi_send_callback(fetch_msg msg,
+		struct fetch_doi_context *ctx, const void *data,
+		unsigned long size, fetch_error_code errorcode)
+{
+	ctx->locked = true;
+	fetch_send_callback(msg, ctx->fetchh, data, size, errorcode);
+	ctx->locked = false;
+
+	return ctx->aborted;
+}
+
+static bool fetch_doi_redirect_handler(struct fetch_doi_context *ctx)
+{
+	/* content is going to return redirect */
+	fetch_set_http_code(ctx->fetchh, 302);
+
+	fetch_doi_send_callback(FETCH_REDIRECT, ctx, ctx->redirect_url, 0,
+			FETCH_ERROR_NO_ERROR);
+
+	return true;
+}
+
+
+/** callback to initialise the resource fetcher. */
+static bool fetch_doi_initialise(const char *scheme)
+{
+	return true;
+}
+
+/** callback to initialise the resource fetcher. */
+static void fetch_doi_finalise(const char *scheme)
+{
+}
+
+/** callback to set up a resource fetch context. */
+static void *
+fetch_doi_setup(struct fetch *fetchh,
+		 const char *url,
+		 bool only_2xx,
+		 const char *post_urlenc,
+		 const struct fetch_multipart_data *post_multipart,
+		 const char **headers)
+{
+	struct fetch_doi_context *ctx;
+
+	ctx = calloc(1, sizeof(*ctx) + strlen(fetch_doi_redirect_base) +
+			strlen(url) + 1);
+	if (ctx == NULL)
+		return NULL;
+
+	sprintf(ctx->redirect_url, "%s%s", fetch_doi_redirect_base,
+			url + SLEN("doi:"));
+
+	ctx->fetchh = fetchh;
+
+	RING_INSERT(ring, ctx);
+
+	return ctx;
+}
+
+/** callback to free a resource fetch */
+static void fetch_doi_free(void *ctx)
+{
+	struct fetch_doi_context *c = ctx;
+	RING_REMOVE(ring, c);
+	free(ctx);
+}
+
+/** callback to start a resource fetch */
+static bool fetch_doi_start(void *ctx)
+{
+	return true;
+}
+
+/** callback to abort a resource fetch */
+static void fetch_doi_abort(void *ctx)
+{
+	struct fetch_doi_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;
+}
+
+
+/** callback to poll for additional resource fetch contents */
+static void fetch_doi_poll(const char *scheme)
+{
+	struct fetch_doi_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) {
+			/* resource fetches can be processed in one go */
+			fetch_doi_redirect_handler(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);
+}
+
+void fetch_doi_register(void)
+{
+	fetch_add_fetcher("doi",
+		fetch_doi_initialise,
+		fetch_doi_setup,
+		fetch_doi_start,
+		fetch_doi_abort,
+		fetch_doi_free,
+		fetch_doi_poll,
+		fetch_doi_finalise);
+}

content/fetchers/doi.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2011 François Revol <mmu_man@users.sourceforge.net>
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+/** \file
+ * doi: URL method handler.
+ * 
+ * The doi fetcher is intended to provide a redirection of doi URLs
+ * to the canonical doi website accessible via HTTP.
+ * cf. http://tools.ietf.org/html/draft-paskin-doi-uri
+ *
+ */
+
+#ifndef NETSURF_CONTENT_FETCHERS_FETCH_DOI_H
+#define NETSURF_CONTENT_FETCHERS_FETCH_DOI_H
+
+/**
+ * Register the resource scheme.
+ * 
+ * should only be called from the fetch initialise
+ */
+void fetch_doi_register(void);
+
+#endif