plugin-manager,plugin: run pre-probing filters early

For each port, we will construct the list of plugins to test with. In that list
we will include those plugins which are likely to handle a given port, so we
will skip all those which aren't.

To see if a plugin is likely or not, we will run the pre-probing filters before
adding them to the list, with the new `mm_plugin_discard_port_early()'. This
method will return one of these hints:

 * UNSUPPORTED: The plugin will not be able to handle this port.
 * MAYBE: The plugin may handle this port.
 * LIKELY: The plugin may (very likely) handle this port.
 * SUPPORTED: If any plugin should support the port, this is it.

Plugins reported to be 'likely' supporting the port will be probed before the
ones reported just as 'maybe'.

If a plugin reports 'supported' only that one and the fallback generic ones will
be tried.

1 files changed, 86 insertions, 33 deletions

diff --git a/src/mm-plugin-manager.c b/src/mm-plugin-manager.c
index d5759b65..56290e19 100644
--- a/src/mm-plugin-manager.c
+++ b/src/mm-plugin-manager.c
@@ -42,9 +42,12 @@ G_DEFINE_TYPE_EXTENDED (MMPluginManager, mm_plugin_manager, G_TYPE_OBJECT, 0,
                                                initable_iface_init));
 
 struct _MMPluginManagerPrivate {
-    /* The list of plugins. It is loaded once when the program starts, and the
-     * list is NOT expected to change after that. */
+    /* This list contains all plugins except for the generic one, order is not
+     * important. It is loaded once when the program starts, and the list is NOT
+     * expected to change after that.*/
     GList *plugins;
+    /* Last, the generic plugin. */
+    MMPlugin *generic;
 };
 
 /*****************************************************************************/
@@ -65,6 +68,7 @@ typedef struct {
     FindDeviceSupportContext *parent_ctx;
     GUdevDevice *port;
 
+    GList *plugins;
     GList *current;
     MMPlugin *best_plugin;
     MMPlugin *suggested_plugin;
@@ -86,6 +90,8 @@ port_probe_context_free (PortProbeContext *ctx)
         g_object_unref (ctx->best_plugin);
     if (ctx->suggested_plugin)
         g_object_unref (ctx->suggested_plugin);
+    if (ctx->plugins)
+        g_list_free_full (ctx->plugins, (GDestroyNotify)g_object_unref);
     g_object_unref (ctx->port);
     g_slice_free (PortProbeContext, ctx);
 }
@@ -426,6 +432,62 @@ port_probe_context_step (PortProbeContext *port_probe_ctx)
                              port_probe_ctx);
 }
 
+static GList *
+build_plugins_list (MMPluginManager *self,
+                    MMDevice *device,
+                    GUdevDevice *port)
+{
+    GList *list = NULL;
+    GList *l;
+    gboolean supported_found = FALSE;
+
+    for (l = self->priv->plugins; l && !supported_found; l = g_list_next (l)) {
+        MMPluginSupportsHint hint;
+
+        hint = mm_plugin_discard_port_early (MM_PLUGIN (l->data), device, port);
+        switch (hint) {
+        case MM_PLUGIN_SUPPORTS_HINT_UNSUPPORTED:
+            /* Fully discard */
+            break;
+        case MM_PLUGIN_SUPPORTS_HINT_MAYBE:
+            /* Maybe supported, add to tail of list */
+            list = g_list_append (list, g_object_ref (l->data));
+            break;
+        case MM_PLUGIN_SUPPORTS_HINT_LIKELY:
+            /* Likely supported, add to head of list */
+            list = g_list_prepend (list, g_object_ref (l->data));
+            break;
+        case MM_PLUGIN_SUPPORTS_HINT_SUPPORTED:
+            /* Really supported, clean existing list and add it alone */
+            if (list) {
+                g_list_free_full (list, (GDestroyNotify)g_object_unref);
+                list = NULL;
+            }
+            list = g_list_prepend (list, g_object_ref (l->data));
+            /* This will end the loop as well */
+            supported_found = TRUE;
+            break;
+        default:
+            g_assert_not_reached();
+        }
+    }
+
+    /* Add the generic plugin at the end of the list */
+    if (self->priv->generic)
+        list = g_list_append (list, g_object_ref (self->priv->generic));
+
+    mm_info ("(Plugin Manager) [%s] Found '%u' plugins to try...",
+             g_udev_device_get_name (port),
+             g_list_length (list));
+    for (l = list; l; l = g_list_next (l)) {
+        mm_info ("(Plugin Manager) [%s]   Will try with plugin '%s'",
+                 g_udev_device_get_name (port),
+                 mm_plugin_get_name (MM_PLUGIN (l->data)));
+    }
+
+    return list;
+}
+
 static void
 device_port_grabbed_cb (MMDevice *device,
                         GUdevDevice *port,
@@ -433,17 +495,15 @@ device_port_grabbed_cb (MMDevice *device,
 {
     PortProbeContext *port_probe_ctx;
 
-    mm_dbg ("(%s/%s) Launching port support check",
-            g_udev_device_get_subsystem (port),
-            g_udev_device_get_name (port));
 
     /* Launch probing task on this port with the first plugin of the list */
     port_probe_ctx = g_slice_new0 (PortProbeContext);
     port_probe_ctx->parent_ctx = ctx;
     port_probe_ctx->port = g_object_ref (port);
 
-    /* Set first plugin to check */
-    port_probe_ctx->current = ctx->self->priv->plugins;
+    /* Setup plugins to probe and first one to check */
+    port_probe_ctx->plugins = build_plugins_list (ctx->self, device, port);
+    port_probe_ctx->current = port_probe_ctx->plugins;
 
     /* If we got one suggested, it will be the first one */
     port_probe_ctx->suggested_plugin = (!!mm_device_peek_plugin (device) ?
@@ -585,9 +645,7 @@ load_plugins (MMPluginManager *self,
 {
     GDir *dir = NULL;
     const gchar *fname;
-    MMPlugin *generic_plugin = NULL;
     gchar *plugindir_display = NULL;
-    GList *l;
 
 	if (!g_module_supported ()) {
         g_set_error (error,
@@ -622,27 +680,25 @@ load_plugins (MMPluginManager *self,
         plugin = load_plugin (path);
         g_free (path);
 
-        if (plugin) {
-            if (g_str_equal (mm_plugin_get_name (plugin),
-                             MM_PLUGIN_GENERIC_NAME))
-                generic_plugin = plugin;
-            else
-                self->priv->plugins = g_list_append (self->priv->plugins,
-                                                     plugin);
-        }
-    }
+        if (!plugin)
+            continue;
+
+        mm_info ("Loaded plugin '%s'", mm_plugin_get_name (plugin));
 
-    /* Sort last plugins that request it */
-    self->priv->plugins = g_list_sort (self->priv->plugins,
-                                       (GCompareFunc)mm_plugin_cmp);
+        if (g_str_equal (mm_plugin_get_name (plugin), MM_PLUGIN_GENERIC_NAME))
+            /* Generic plugin */
+            self->priv->generic = plugin;
+        else
+            /* Vendor specific plugin */
+            self->priv->plugins = g_list_append (self->priv->plugins, plugin);
+    }
 
-    /* Make sure the generic plugin is last */
-    if (generic_plugin)
-        self->priv->plugins = g_list_append (self->priv->plugins,
-                                             generic_plugin);
+    /* Check the generic plugin once all looped */
+    if (!self->priv->generic)
+        mm_warn ("Generic plugin not loaded");
 
     /* Treat as error if we don't find any plugin */
-    if (!self->priv->plugins) {
+    if (!self->priv->plugins && !self->priv->generic) {
         g_set_error (error,
                      MM_CORE_ERROR,
                      MM_CORE_ERROR_NO_PLUGINS,
@@ -651,20 +707,16 @@ load_plugins (MMPluginManager *self,
         goto out;
     }
 
-    /* Now report about all the found plugins, in the same order they will be
-     * used while checking support */
-    for (l = self->priv->plugins; l; l = g_list_next (l))
-        mm_info ("Loaded plugin '%s'", mm_plugin_get_name (MM_PLUGIN (l->data)));
-
     mm_info ("Successfully loaded %u plugins",
-             g_list_length (self->priv->plugins));
+             g_list_length (self->priv->plugins) + !!self->priv->generic);
 
 out:
     if (dir)
         g_dir_close (dir);
     g_free (plugindir_display);
 
-    return !!self->priv->plugins;
+    /* Return TRUE if at least one plugin found */
+    return (self->priv->plugins || self->priv->generic);
 }
 
 MMPluginManager *
@@ -704,6 +756,7 @@ dispose (GObject *object)
         g_list_free_full (self->priv->plugins, (GDestroyNotify)g_object_unref);
         self->priv->plugins = NULL;
     }
+    g_clear_object (&self->priv->generic);
 
     G_OBJECT_CLASS (mm_plugin_manager_parent_class)->dispose (object);
 }