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.

3 files changed, 152 insertions, 64 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);
 }
diff --git a/src/mm-plugin.c b/src/mm-plugin.c
index fff6f0a8..5069f0ee 100644
--- a/src/mm-plugin.c
+++ b/src/mm-plugin.c
@@ -43,31 +43,48 @@ G_DEFINE_TYPE (MMPlugin, mm_plugin, G_TYPE_OBJECT)
 /* Virtual port corresponding to the embeded modem */
 static gchar *virtual_port[] = {"smd0", NULL};
 
+#define HAS_POST_PROBING_FILTERS(self)          \
+    (self->priv->vendor_strings ||              \
+     self->priv->product_strings ||             \
+     self->priv->forbidden_product_strings ||   \
+     self->priv->allowed_icera ||               \
+     self->priv->forbidden_icera ||             \
+     self->priv->custom_init)
+
+
 struct _MMPluginPrivate {
     gchar *name;
     GHashTable *tasks;
 
-    /* Plugin-specific setups */
+    /* Pre-probing filters */
     gchar **subsystems;
     gchar **drivers;
     gchar **forbidden_drivers;
     guint16 *vendor_ids;
     mm_uint16_pair *product_ids;
     mm_uint16_pair *forbidden_product_ids;
+    gchar **udev_tags;
+
+    /* Post probing filters */
     gchar **vendor_strings;
     mm_str_pair *product_strings;
     mm_str_pair *forbidden_product_strings;
-    gchar **udev_tags;
+    gboolean allowed_icera;
+    gboolean forbidden_icera;
+
+    /* Probing setup */
     gboolean at;
     gboolean single_at;
     gboolean qcdm;
     gboolean icera_probe;
-    gboolean allowed_icera;
-    gboolean forbidden_icera;
     MMPortProbeAtCommand *custom_at_probe;
-    MMAsyncMethod *custom_init;
     guint64 send_delay;
     gboolean remove_echo;
+
+    /* Probing setup and/or post-probing filter.
+     * Plugins may use this method to decide whether they support a given
+     * port or not, so should also be considered kind of post-probing filter. */
+    MMAsyncMethod *custom_init;
 };
 
 enum {
@@ -106,30 +123,6 @@ mm_plugin_get_name (MMPlugin *self)
 
 /*****************************************************************************/
 
-gint
-mm_plugin_cmp (const MMPlugin *plugin_a,
-               const MMPlugin *plugin_b)
-{
-    /* If we have any post-probing filter, we need to sort the plugin last */
-#define SORT_LAST(self) (self->priv->vendor_strings || \
-                         self->priv->product_strings || \
-                         self->priv->forbidden_product_strings)
-
-    /* The order of the plugins in the list is the same order used to check
-     * whether the plugin can manage a given modem:
-     *  - First, modems that will check vendor ID from udev.
-     *  - Then, modems that report to be sorted last (those which will check
-     *    vendor ID also from the probed ones..
-     */
-    if (SORT_LAST (plugin_a) && !SORT_LAST (plugin_b))
-        return 1;
-    if (!SORT_LAST (plugin_a) && SORT_LAST (plugin_b))
-        return -1;
-    return 0;
-}
-
-/*****************************************************************************/
-
 static gboolean
 device_file_exists (const char *name)
 {
@@ -747,6 +740,37 @@ out:
 
 /*****************************************************************************/
 
+MMPluginSupportsHint
+mm_plugin_discard_port_early (MMPlugin *self,
+                              MMDevice *device,
+                              GUdevDevice *port)
+{
+    gboolean need_vendor_probing = FALSE;
+    gboolean need_product_probing = FALSE;
+
+    /* If fully filtered by pre-probing filters, port unsupported */
+    if (apply_pre_probing_filters (self,
+                                   device,
+                                   port,
+                                   &need_vendor_probing,
+                                   &need_product_probing))
+        return MM_PLUGIN_SUPPORTS_HINT_UNSUPPORTED;
+
+    /* If there are no post-probing filters, this plugin is the only one (except
+     * for the generic one) which will grab the port */
+    if (!HAS_POST_PROBING_FILTERS (self))
+        return MM_PLUGIN_SUPPORTS_HINT_SUPPORTED;
+
+    /* If  no vendor/product probing needed, plugin is likely supported */
+    if (!need_vendor_probing && !need_product_probing)
+        return MM_PLUGIN_SUPPORTS_HINT_LIKELY;
+
+    /* If vendor/product probing is needed, plugin may be supported */
+    return MM_PLUGIN_SUPPORTS_HINT_MAYBE;
+}
+
+/*****************************************************************************/
+
 MMBaseModem *
 mm_plugin_create_modem (MMPlugin  *self,
                         MMDevice *device,
diff --git a/src/mm-plugin.h b/src/mm-plugin.h
index 6d5d14e1..a423ceb0 100644
--- a/src/mm-plugin.h
+++ b/src/mm-plugin.h
@@ -67,6 +67,13 @@ typedef enum {
     MM_PLUGIN_SUPPORTS_PORT_SUPPORTED
 } MMPluginSupportsResult;
 
+typedef enum {
+    MM_PLUGIN_SUPPORTS_HINT_UNSUPPORTED,
+    MM_PLUGIN_SUPPORTS_HINT_MAYBE,
+    MM_PLUGIN_SUPPORTS_HINT_LIKELY,
+    MM_PLUGIN_SUPPORTS_HINT_SUPPORTED,
+} MMPluginSupportsHint;
+
 typedef struct _MMPlugin MMPlugin;
 typedef struct _MMPluginClass MMPluginClass;
 typedef struct _MMPluginPrivate MMPluginPrivate;
@@ -102,8 +109,12 @@ struct _MMPluginClass {
 GType mm_plugin_get_type (void);
 
 const gchar *mm_plugin_get_name (MMPlugin *plugin);
-gint         mm_plugin_cmp      (const MMPlugin *plugin_a,
-                                 const MMPlugin *plugin_b);
+
+/* This method will run all pre-probing filters, to see if we can discard this
+ * plugin from the probing logic as soon as possible. */
+MMPluginSupportsHint mm_plugin_discard_port_early (MMPlugin *plugin,
+                                                   MMDevice *device,
+                                                   GUdevDevice *port);
 
 void                   mm_plugin_supports_port        (MMPlugin *plugin,
                                                        MMDevice *device,