[glib] API: Reinstate "gio-desktop-app-info-lookup" extension point

[Benjamin Otte <otte src gnome org>]

commit fb94859e84c0b7859a0a5425d461b18e67ea9ac7
Author: Benjamin Otte <otte redhat com>
Date:   Tue Nov 9 07:19:19 2010 -0500

    API: Reinstate "gio-desktop-app-info-lookup" extension point
    
    Removing an extension point is an API and ABI break. In particular, it
    causes (older) gvfs versions to fail loading with a linkage error from
    ld which in turn makes the desktop unusable.
    So this reinstate the extension point and API provided by it, but
    deprecates and does not use it. So no functionality is changed.
    
    This reverts parts of commit 9b262f1c5fe5a6fd879f17cd7b80d8c54e33d80c.
    
    Complaints-Also-To: Ryan Lortie <desrt desrt ca>

 gio/gdesktopappinfo.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 gio/gdesktopappinfo.h |   40 ++++++++++++++++++++++++++++++++++++++++
 gio/gio.symbols       |    2 ++
 gio/giomodule.c       |   16 +++++++++++++---
 4 files changed, 97 insertions(+), 3 deletions(-)
---
diff --git a/gio/gdesktopappinfo.c b/gio/gdesktopappinfo.c
index 8047d9c..99a6fb7 100644
--- a/gio/gdesktopappinfo.c
+++ b/gio/gdesktopappinfo.c
@@ -32,6 +32,8 @@
 #include <crt_externs.h>
 #endif
 
+#undef G_DISABLE_DEPRECATED
+
 #include "gcontenttypeprivate.h"
 #include "gdesktopappinfo.h"
 #include "gfile.h"
@@ -2638,3 +2640,43 @@ get_all_desktop_entries_for_mime_type (const char *base_mime_type,
   return desktop_entries;
 }
 
+/* GDesktopAppInfoLookup interface: */
+
+typedef GDesktopAppInfoLookupIface GDesktopAppInfoLookupInterface;
+G_DEFINE_INTERFACE (GDesktopAppInfoLookup, g_desktop_app_info_lookup, G_TYPE_OBJECT)
+
+static void
+g_desktop_app_info_lookup_default_init (GDesktopAppInfoLookupInterface *iface)
+{
+}
+
+/**
+ * g_desktop_app_info_lookup_get_default_for_uri_scheme:
+ * @lookup: a #GDesktopAppInfoLookup
+ * @uri_scheme: a string containing a URI scheme.
+ *
+ * Gets the default application for launching applications 
+ * using this URI scheme for a particular GDesktopAppInfoLookup
+ * implementation.
+ *
+ * The GDesktopAppInfoLookup interface and this function is used
+ * to implement g_app_info_get_default_for_uri_scheme() backends
+ * in a GIO module. There is no reason for applications to use it
+ * directly. Applications should use g_app_info_get_default_for_uri_scheme().
+ * 
+ * Returns: (transfer full): #GAppInfo for given @uri_scheme or %NULL on error.
+ *
+ * Deprecated: The #GDesktopAppInfoLookup interface is deprecated and unused by gio.
+ */
+GAppInfo *
+g_desktop_app_info_lookup_get_default_for_uri_scheme (GDesktopAppInfoLookup *lookup,
+						      const char            *uri_scheme)
+{
+  GDesktopAppInfoLookupIface *iface;
+  
+  g_return_val_if_fail (G_IS_DESKTOP_APP_INFO_LOOKUP (lookup), NULL);
+
+  iface = G_DESKTOP_APP_INFO_LOOKUP_GET_IFACE (lookup);
+
+  return (* iface->get_default_for_uri_scheme) (lookup, uri_scheme);
+}
diff --git a/gio/gdesktopappinfo.h b/gio/gdesktopappinfo.h
index d7703f7..6be9369 100644
--- a/gio/gdesktopappinfo.h
+++ b/gio/gdesktopappinfo.h
@@ -55,6 +55,46 @@ gboolean         g_desktop_app_info_get_is_hidden     (GDesktopAppInfo *info);
 
 void             g_desktop_app_info_set_desktop_env   (const char      *desktop_env);
 
+
+#ifndef G_DISABLE_DEPRECATED
+
+#define G_TYPE_DESKTOP_APP_INFO_LOOKUP           (g_desktop_app_info_lookup_get_type ())
+#define G_DESKTOP_APP_INFO_LOOKUP(obj)           (G_TYPE_CHECK_INSTANCE_CAST ((obj), G_TYPE_DESKTOP_APP_INFO_LOOKUP, GDesktopAppInfoLookup))
+#define G_IS_DESKTOP_APP_INFO_LOOKUP(obj)	 (G_TYPE_CHECK_INSTANCE_TYPE ((obj), G_TYPE_DESKTOP_APP_INFO_LOOKUP))
+#define G_DESKTOP_APP_INFO_LOOKUP_GET_IFACE(obj) (G_TYPE_INSTANCE_GET_INTERFACE ((obj), G_TYPE_DESKTOP_APP_INFO_LOOKUP, GDesktopAppInfoLookupIface))
+
+/**
+ * G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME:
+ *
+ * Extension point for default handler to URI association. See
+ * <link linkend="extending-gio">Extending GIO</link>.
+ */
+#define G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME "gio-desktop-app-info-lookup"
+
+/**
+ * GDesktopAppInfoLookup:
+ *
+ * Interface that is used by backends to associate default
+ * handlers with URI schemes.
+ */
+typedef struct _GDesktopAppInfoLookup GDesktopAppInfoLookup;
+typedef struct _GDesktopAppInfoLookupIface GDesktopAppInfoLookupIface;
+
+struct _GDesktopAppInfoLookupIface
+{
+  GTypeInterface g_iface;
+
+  GAppInfo * (* get_default_for_uri_scheme) (GDesktopAppInfoLookup *lookup,
+                                             const char            *uri_scheme);
+};
+
+GType     g_desktop_app_info_lookup_get_type                   (void) G_GNUC_CONST;
+
+GAppInfo *g_desktop_app_info_lookup_get_default_for_uri_scheme (GDesktopAppInfoLookup *lookup,
+                                                                const char            *uri_scheme);
+
+#endif /* G_DISABLE_DEPRECATED */
+
 G_END_DECLS
 
 #endif /* __G_DESKTOP_APP_INFO_H__ */
diff --git a/gio/gio.symbols b/gio/gio.symbols
index eb79b70..90ea290 100644
--- a/gio/gio.symbols
+++ b/gio/gio.symbols
@@ -131,6 +131,8 @@ g_desktop_app_info_get_filename
 g_desktop_app_info_get_type G_GNUC_CONST
 g_desktop_app_info_get_is_hidden
 g_desktop_app_info_set_desktop_env
+g_desktop_app_info_lookup_get_type G_GNUC_CONST
+g_desktop_app_info_lookup_get_default_for_uri_scheme
 #endif
 #endif
 #endif
diff --git a/gio/giomodule.c b/gio/giomodule.c
index 86bf25e..d131893 100644
--- a/gio/giomodule.c
+++ b/gio/giomodule.c
@@ -36,14 +36,17 @@
 #include "gsocks4aproxy.h"
 #include "gsocks5proxy.h"
 #include "gvfs.h"
-#ifdef G_OS_UNIX
-#include "gdesktopappinfo.h"
-#endif
 #ifdef G_OS_WIN32
 #include "gregistrysettingsbackend.h"
 #endif
 #include <glib/gstdio.h>
 
+#undef G_DISABLE_DEPRECATED
+
+#ifdef G_OS_UNIX
+#include "gdesktopappinfo.h"
+#endif
+
 /**
  * SECTION:giomodule
  * @short_description: Loadable GIO Modules
@@ -523,6 +526,13 @@ _g_io_modules_ensure_extension_points_registered (void)
     {
       registered_extensions = TRUE;
       
+#ifdef G_OS_UNIX
+#if !GLIB_CHECK_VERSION (3, 0, 0)
+      ep = g_io_extension_point_register (G_DESKTOP_APP_INFO_LOOKUP_EXTENSION_POINT_NAME);
+      g_io_extension_point_set_required_type (ep, G_TYPE_DESKTOP_APP_INFO_LOOKUP);
+#endif
+#endif
+      
       ep = g_io_extension_point_register (G_LOCAL_DIRECTORY_MONITOR_EXTENSION_POINT_NAME);
       g_io_extension_point_set_required_type (ep, G_TYPE_LOCAL_DIRECTORY_MONITOR);