Plugin system for backends. Fixes bug #351348.

2007-12-28  Carlos Garcia Campos  <carlosgc@gnome.org>
	* configure.ac:
	* Makefile.am:
	* po/POTFILES.in:
	* backend/comics/Makefile.am:
	* backend/comics/comics-document.[ch]:
	* backend/comics/comicsdocument.evince-backend.in:
	* backend/djvu/Makefile.am:
	* backend/djvu/djvu-document.[ch]:
	* backend/djvu/djvudocument.evince-backend.in:
	* backend/dvi/Makefile.am:
	* backend/dvi/dvi-document.[c]:
	* backend/dvi/dvidocument.evince-backend.in:
	* backend/impress/Makefile.am:
	* backend/impress/impress-document.[ch]:
	* backend/impress/impressdocument.evince-backend.in:
	* backend/pdf/Makefile.am:
	* backend/pdf/ev-poppler.cc:
	* backend/pdf/ev-poppler.h:
	* backend/pdf/pdfdocument.evince-backend.in:
	* backend/pixbuf/Makefile.am:
	* backend/pixbuf/pixbuf-document.[ch]:
	* backend/pixbuf/pixbufdocument.evince-backend.in:
	* backend/ps/Makefile.am:
	* backend/ps/ev-spectre.[ch]:
	* backend/ps/ps-document.[ch]:
	* backend/ps/psdocument.evince-backend.in:
	* backend/tiff/Makefile.am:
	* backend/tiff/tiff-document.[ch]:
	* backend/tiff/tiffdocument.evince-backend.in:
	* libdocument/Makefile.am:
	* libdocument/ev-backends-manager.[ch]:
	* libdocument/ev-module.[ch]:
	* libdocument/ev-document.h:
	* libdocument/ev-document-factory.[ch]:
	(gdk_pixbuf_mime_type_list), (mime_type_supported_by_gdk_pixbuf),
	(get_compression_from_mime_type), (get_document_from_uri),
	(ev_document_factory_get_document), (file_filter_add_mime_types),
	(ev_document_factory_add_filters):
	* shell/Makefile.am:
	* shell/ev-window-title.c: (get_filename_from_uri):
	* shell/main.c: (main):
	* thumbnailer/Makefile.am:
	* thumbnailer/evince-thumbnailer.c: (main):
	Plugin system for backends. Fixes bug #351348.

svn path=/trunk/; revision=2786

1 files changed, 291 insertions, 0 deletions

diff --git a/libdocument/ev-backends-manager.c b/libdocument/ev-backends-manager.c
new file mode 100644
index 0000000..0f501a1
--- /dev/null
+++ b/libdocument/ev-backends-manager.c
@@ -0,0 +1,291 @@
+/* this file is part of evince, a gnome document viewer
+ *
+ *  Copyright (C) 2007 Carlos Garcia Campos <carlosgc@gnome.org>
+ *
+ * Evince 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Evince 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <config.h>
+
+#include <glib/gstdio.h>
+
+#include "ev-module.h"
+#include "ev-backends-manager.h"
+
+static GList *ev_backends_list = NULL;
+
+typedef struct _EvBackendInfo EvBackendInfo;
+struct _EvBackendInfo {
+	gchar       *module_name;
+	GTypeModule *module;
+
+	GType        type_id;
+
+	gchar       *type_desc;
+	gchar      **mime_types;
+};
+
+#define EV_BACKENDS_GROUP     "Evince Backend"
+#define EV_BACKENDS_EXTENSION ".evince-backend"
+
+static void
+ev_backend_info_free (EvBackendInfo *info)
+{
+	g_free (info->module_name);
+	g_free (info->type_desc);
+	g_strfreev (info->mime_types);
+	g_free (info);
+}
+
+static EvBackendInfo *
+ev_backends_manager_load_backend (const gchar *file)
+{
+	EvBackendInfo *info;
+	GKeyFile      *backend_file = NULL;
+	GError        *error = NULL;
+
+	backend_file = g_key_file_new ();
+	if (!g_key_file_load_from_file (backend_file, file, G_KEY_FILE_NONE, &error)) {
+		g_warning ("Error opening backend file %s: %s",
+			   file, error->message);
+		g_error_free (error);
+		g_key_file_free (backend_file);
+
+		return NULL;
+	}
+
+	info = g_new0 (EvBackendInfo, 1);
+	info->module_name = g_key_file_get_string (backend_file, EV_BACKENDS_GROUP,
+						   "Module", NULL);
+	if (!info->module_name) {
+		g_warning ("Bad evince backend file %s: Could not find 'Module'",
+			   file);
+		ev_backend_info_free (info);
+		g_key_file_free (backend_file);
+
+		return NULL;
+	}
+
+	info->type_desc = g_key_file_get_locale_string (backend_file, EV_BACKENDS_GROUP,
+							"TypeDescription", NULL, NULL);
+	if (!info->type_desc) {
+		g_warning ("Bad evince backend file %s: Could not find 'TypeDescription'",
+			   file);
+		ev_backend_info_free (info);
+		g_key_file_free (backend_file);
+
+		return NULL;
+	}
+
+	info->mime_types = g_key_file_get_string_list (backend_file, EV_BACKENDS_GROUP,
+						       "MimeType", NULL, NULL);
+	if (!info->mime_types) {
+		g_warning ("Bad evince backend file %s: Could not find 'MimeType'",
+			   file);
+		ev_backend_info_free (info);
+		g_key_file_free (backend_file);
+
+		return NULL;
+	}
+
+	g_key_file_free (backend_file);
+
+	return info;
+}
+
+static gboolean
+ev_backends_manager_load (void)
+{
+	GDir        *dir;
+	const gchar *dirent;
+	GError      *error = NULL;
+
+	dir = g_dir_open (EV_BACKENDSDIR, 0, &error);
+	if (!dir) {
+		g_warning (error->message);
+		g_error_free (error);
+
+		return FALSE;
+	}
+
+	while ((dirent = g_dir_read_name (dir))) {
+		EvBackendInfo *info;
+		gchar         *file;
+		
+		if (!g_str_has_suffix (dirent, EV_BACKENDS_EXTENSION))
+			continue;
+
+		file = g_build_filename (EV_BACKENDSDIR, dirent, NULL);
+		info = ev_backends_manager_load_backend (file);
+		g_free (file);
+
+		if (!info)
+			continue;
+		
+		ev_backends_list = g_list_prepend (ev_backends_list, info);
+	}
+
+	return TRUE;
+}
+
+gboolean
+ev_backends_manager_init (void)
+{
+	if (ev_backends_list)
+		return FALSE;
+
+	return ev_backends_manager_load ();
+}
+
+void
+ev_backends_manager_shutdown (void)
+{
+	g_list_foreach (ev_backends_list, (GFunc)ev_backend_info_free, NULL);
+	g_list_free (ev_backends_list);
+	ev_backends_list = NULL;
+}
+
+static EvBackendInfo *
+ev_backends_manager_get_backend_info (const gchar *mime_type)
+{
+	GList *l;
+
+	for (l = ev_backends_list; l; l = g_list_next (l)) {
+		EvBackendInfo *info;
+		gint           i = 0;
+		const char    *mime;
+		
+		info = (EvBackendInfo *)l->data;
+		
+		while ((mime = info->mime_types[i++])) {
+			if (g_ascii_strcasecmp (mime, mime_type) == 0)
+				return info;
+		}
+	}
+
+	return NULL;
+}
+
+EvDocument *
+ev_backends_manager_get_document (const gchar *mime_type)
+{
+	EvDocument    *document;
+	EvBackendInfo *info;
+
+	info = ev_backends_manager_get_backend_info (mime_type);
+	if (!info)
+		return NULL;
+
+	if (!info->module) {
+		gchar *path;
+		
+		path = g_module_build_path (EV_BACKENDSDIR, info->module_name);
+		info->module = G_TYPE_MODULE (ev_module_new (path));
+		g_free (path);
+	}
+	
+	if (!g_type_module_use (info->module)) {
+		g_warning ("Cannot load backend '%s' since file '%s' cannot be read.",
+			   info->module_name,
+			   ev_module_get_path (EV_MODULE (info->module)));
+		g_object_unref (G_OBJECT (info->module));
+		info->module = NULL;
+
+		return NULL;
+	}
+
+	document = EV_DOCUMENT (ev_module_new_object (EV_MODULE (info->module)));
+	g_type_module_unuse (info->module);
+
+	return document;
+}
+
+static EvBackendInfo *
+get_document_backend_info (EvDocument *document)
+{
+	GList *l;
+
+	for (l = ev_backends_list; l; l = g_list_next (l)) {
+		EvBackendInfo *info;
+		GType          type_id;
+
+		info = (EvBackendInfo *)l->data;
+
+		if (!info->module)
+			continue;
+
+		type_id = ev_module_get_object_type (EV_MODULE (info->module));
+
+		if (G_TYPE_CHECK_INSTANCE_TYPE (document, type_id)) {
+			return info;
+		}
+	}
+
+	return NULL;
+}
+
+const gchar *
+ev_backends_manager_get_document_module_name (EvDocument *document)
+{
+	EvBackendInfo *info;
+
+	info = get_document_backend_info (document);
+	return info ? info->module_name : NULL;
+}
+
+static EvTypeInfo *
+ev_type_info_new (const gchar *desc, const gchar **mime_types)
+{
+	EvTypeInfo *info;
+
+	info = g_new (EvTypeInfo, 1);
+
+	info->desc = desc;
+	info->mime_types = mime_types;
+
+	return info;
+}
+
+EvTypeInfo *
+ev_backends_manager_get_document_type_info (EvDocument *document)
+{
+	EvBackendInfo *info;
+
+	info = get_document_backend_info (document);
+	return info ?
+		ev_type_info_new (info->type_desc,
+				  (const gchar **)info->mime_types)
+		: NULL;
+}
+
+GList *
+ev_backends_manager_get_all_types_info (void)
+{
+	GList *l;
+	GList *retval = NULL;
+
+	for (l = ev_backends_list; l; l = g_list_next (l)) {
+		EvBackendInfo *info;
+		EvTypeInfo    *type_info;
+
+		info = (EvBackendInfo *)l->data;
+
+		type_info = ev_type_info_new (info->type_desc,
+					      (const gchar **)info->mime_types);
+		retval = g_list_prepend (retval, type_info);
+	}
+
+	return retval;
+}