Add plugin interface for cache and thumbnailer implementations.

This is a major refactoring of the source code. Amongst others, the
classes TumblerProviderFactory, TumblerThumbnailer,
TumblerAbstractThumbnailer, TumblerThumbnailerProvider, TumblerCache,
TumblerCacheProvider and TumblerFileInfo have been added.

From now on tumbler supports different storage backends and thumbnailers
as plugins. Storage backends have to implement TumblerCache,
thumbnailers have to implement TumblerThumbnailer.

Plugins have to implement three methods: tumbler_plugin_initialize(),
tumbler_plugin_shutdown() and tumbler_plugin_get_types(). The latter
is expected to return a list of provider types for cache or thumbnailer
implementations.

Two example plugins have been added, one for the XDG thumbnail cache
and one for a GdkPixbuf based thumbnailer.

The code of tumblerd was updated to reflect these changes in libtumbler.

1 files changed, 58 insertions, 0 deletions

diff --git a/tumbler/tumbler-cache.h b/tumbler/tumbler-cache.h
new file mode 100644
index 0000000..fa4f8b6
--- /dev/null
+++ b/tumbler/tumbler-cache.h
@@ -0,0 +1,58 @@
+/* vi:set et ai sw=2 sts=2 ts=2: */
+/*-
+ * Copyright (c) 2009 Jannis Pohlmann <jannis@xfce.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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 Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General 
+ * Public License along with this library; if not, write to the 
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#if !defined (TUMBLER_INSIDE_TUMBLER_H) && !defined (TUMBLER_COMPILATION)
+#error "Only <tumbler/tumbler.h> may be included directly. This file might disappear or change contents."
+#endif
+
+#ifndef __TUMBLER_CACHE_H__
+#define __TUMBLER_CACHE_H__
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define TUMBLER_TYPE_CACHE           (tumbler_cache_get_type ())
+#define TUMBLER_CACHE(obj)           (G_TYPE_CHECK_INSTANCE_CAST ((obj), TUMBLER_TYPE_CACHE, TumblerCache))
+#define TUMBLER_IS_CACHE(obj)        (G_TYPE_CHECK_INSTANCE_TYPE ((obj), TUMBLER_TYPE_CACHE))
+#define TUMBLER_CACHE_GET_IFACE(obj) (G_TYPE_INSTANCE_GET_INTERFACE ((obj), TUMBLER_TYPE_CACHE, TumblerCacheIface))
+
+typedef struct _TumblerCache      TumblerCache;
+typedef struct _TumblerCacheIface TumblerCacheIface;
+
+struct _TumblerCacheIface
+{
+  GTypeInterface __parent__;
+
+  /* signals */
+
+  /* virtual methods */
+  GList *(*get_thumbnails) (TumblerCache *cache,
+                            const gchar  *uri);
+};
+
+GType  tumbler_cache_get_type (void) G_GNUC_CONST;
+
+GList *tumbler_cache_get_thumbnails (TumblerCache *cache,
+                                     const gchar  *uri) G_GNUC_MALLOC G_GNUC_WARN_UNUSED_RESULT;
+
+G_END_DECLS
+
+#endif /* !__TUMBLER_CACHE_H__ */