Initial plugin manager

1 files changed, 260 insertions, 0 deletions

diff --git a/src/uca-plugin-manager.c b/src/uca-plugin-manager.c
new file mode 100644
index 0000000..7788678
--- /dev/null
+++ b/src/uca-plugin-manager.c
@@ -0,0 +1,260 @@
+/**
+ * SECTION:uca-plugin-manager
+ * @Short_description: Load an #UcaFilter from a shared object
+ * @Title: UcaPluginManager
+ *
+ * The plugin manager opens shared object modules searched for in locations
+ * specified with uca_plugin_manager_add_paths(). An #UcaFilter can be
+ * instantiated with uca_plugin_manager_get_filter() with a one-to-one mapping
+ * between filter name xyz and module name libfilterxyz.so. Any errors are
+ * reported as one of #UcaPluginManagerError codes.
+ */
+#include <gmodule.h>
+#include "uca-plugin-manager.h"
+
+G_DEFINE_TYPE (UcaPluginManager, uca_plugin_manager, G_TYPE_OBJECT)
+
+#define UCA_PLUGIN_MANAGER_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE((obj), UCA_TYPE_PLUGIN_MANAGER, UcaPluginManagerPrivate))
+
+struct _UcaPluginManagerPrivate {
+    GList *search_paths;
+};
+
+/**
+ * UcaPluginManagerError:
+ * @UCA_PLUGIN_MANAGER_ERROR_MODULE_NOT_FOUND: The module could not be found
+ * @UCA_PLUGIN_MANAGER_ERROR_MODULE_OPEN: Module could not be opened
+ * @UCA_PLUGIN_MANAGER_ERROR_SYMBOL_NOT_FOUND: Necessary entry symbol was not
+ *      found
+ *
+ * Possible errors that uca_plugin_manager_get_filter() can return.
+ */
+GQuark
+uca_plugin_manager_error_quark (void)
+{
+    return g_quark_from_static_string ("uca-plugin-manager-error-quark");
+}
+
+/**
+ * uca_plugin_manager_new:
+ * @config: (allow-none): A #UcaConfiguration object or %NULL.
+ *
+ * Create a plugin manager object to instantiate filter objects. When a config
+ * object is passed to the constructor, its search-path property is added to the
+ * internal search paths.
+ *
+ * Return value: A new plugin manager object.
+ */
+UcaPluginManager *
+uca_plugin_manager_new ()
+{
+    return UCA_PLUGIN_MANAGER (g_object_new (UCA_TYPE_PLUGIN_MANAGER, NULL));
+}
+
+void
+uca_plugin_manager_add_path (UcaPluginManager   *manager,
+                             const gchar        *path)
+{
+    g_return_if_fail (UCA_IS_PLUGIN_MANAGER (manager));
+
+    if (g_file_test (path, G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR)) {
+        UcaPluginManagerPrivate *priv;
+
+        priv = manager->priv;
+        priv->search_paths = g_list_append (priv->search_paths,
+                                            g_strdup (path));
+    }
+}
+
+static GList *
+get_camera_names_from_directory (const gchar *path)
+{
+    static const gchar *pattern_string = "libuca([A-Za-z]+)";
+    GRegex *pattern; 
+    GDir *dir;
+    GList *result = NULL;
+    
+    pattern = g_regex_new (pattern_string, 0, 0, NULL);
+    dir = g_dir_open (path, 0, NULL);
+
+    if (dir != NULL) {
+        GMatchInfo *match_info = NULL;
+        const gchar *name = g_dir_read_name (dir); 
+
+        while (name != NULL) {
+            g_regex_match (pattern, name, 0, &match_info);
+
+            if (g_match_info_matches (match_info)) {
+                gchar *word = g_match_info_fetch (match_info, 1);
+                result = g_list_append (result, word);
+            }
+
+            name = g_dir_read_name (dir);
+        }
+    }
+
+    return result;
+}
+
+GList *
+uca_plugin_manager_get_available_cameras (UcaPluginManager *manager)
+{
+    UcaPluginManagerPrivate *priv;
+    GList *camera_names;
+
+    g_return_val_if_fail (UCA_IS_PLUGIN_MANAGER (manager), NULL);
+
+    priv = manager->priv;
+
+    for (GList *it = g_list_first (priv->search_paths); it != NULL; it = g_list_next (it)) {
+        camera_names = g_list_concat (camera_names,
+                                      get_camera_names_from_directory ((const gchar*) it->data));
+    }
+
+    return camera_names;
+}
+
+UcaCamera *
+uca_plugin_manager_new_camera (UcaPluginManager   *manager,
+                               const gchar        *name,
+                               GError            **error)
+{
+    return NULL;
+}
+
+/**
+ * uca_plugin_manager_get_filter:
+ * @manager: A #UcaPluginManager
+ * @name: Name of the plugin.
+ * @error: return location for a GError or %NULL
+ *
+ * Load a #UcaFilter module and return an instance. The shared object name must
+ * be * constructed as "libfilter@name.so".
+ *
+ * Returns: (transfer none) (allow-none): #UcaFilter or %NULL if module cannot be found
+ *
+ * Since: 0.2, the error parameter is available
+ */
+/* UcaFilter * */
+/* uca_plugin_manager_get_filter (UcaPluginManager *manager, const gchar *name, GError **error) */
+/* { */
+/*     g_return_val_if_fail (UCA_IS_PLUGIN_MANAGER (manager) && (name != NULL), NULL); */
+/*     UcaPluginManagerPrivate *priv = UCA_PLUGIN_MANAGER_GET_PRIVATE (manager); */
+/*     UcaFilter *filter; */
+/*     GetFilterFunc *func = NULL; */
+/*     GModule *module = NULL; */
+/*     gchar *module_name = NULL; */
+/*     const gchar *entry_symbol_name = "uca_filter_plugin_new"; */
+
+/*     func = g_hash_table_lookup (priv->filter_funcs, name); */
+
+/*     if (func == NULL) { */
+/*         module_name = g_strdup_printf ("libucafilter%s.so", name); */
+/*         gchar *path = plugin_manager_get_path (priv, module_name); */
+
+/*         if (path == NULL) { */
+/*             g_set_error (error, UCA_PLUGIN_MANAGER_ERROR, UCA_PLUGIN_MANAGER_ERROR_MODULE_NOT_FOUND, */
+/*                     "Module %s not found", module_name); */
+/*             goto handle_error; */
+/*         } */
+
+/*         module = g_module_open (path, G_MODULE_BIND_LAZY); */
+/*         g_free (path); */
+
+/*         if (!module) { */
+/*             g_set_error (error, UCA_PLUGIN_MANAGER_ERROR, UCA_PLUGIN_MANAGER_ERROR_MODULE_OPEN, */
+/*                     "Module %s could not be opened: %s", module_name, g_module_error ()); */
+/*             goto handle_error; */
+/*         } */
+
+/*         func = g_malloc0 (sizeof (GetFilterFunc)); */
+
+/*         if (!g_module_symbol (module, entry_symbol_name, (gpointer *) func)) { */
+/*             g_set_error (error, UCA_PLUGIN_MANAGER_ERROR, UCA_PLUGIN_MANAGER_ERROR_SYMBOL_NOT_FOUND, */
+/*                     "%s is not exported by module %s: %s", entry_symbol_name, module_name, g_module_error ()); */
+/*             g_free (func); */
+
+/*             if (!g_module_close (module)) */
+/*                 g_warning ("%s", g_module_error ()); */
+
+/*             goto handle_error; */
+/*         } */
+
+/*         priv->modules = g_slist_append (priv->modules, module); */
+/*         g_hash_table_insert (priv->filter_funcs, g_strdup (name), func); */
+/*         g_free (module_name); */
+/*     } */
+
+/*     filter = (*func) (); */
+/*     uca_filter_set_plugin_name (filter, name); */
+/*     g_message ("UcaPluginManager: Created %s-%p", name, (gpointer) filter); */
+
+/*     return filter; */
+
+/* handle_error: */
+/*     g_free (module_name); */
+/*     return NULL; */
+/* } */
+
+static void
+uca_plugin_manager_get_property (GObject *object, guint property_id, GValue *value, GParamSpec *pspec)
+{
+    switch (property_id) {
+        default:
+            G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+            break;
+    }
+}
+
+static void
+uca_plugin_manager_set_property (GObject *object, guint property_id, const GValue *value, GParamSpec *pspec)
+{
+    switch (property_id) {
+        default:
+            G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+            break;
+    }
+}
+
+static void
+uca_plugin_manager_dispose (GObject *object)
+{
+    G_OBJECT_CLASS (uca_plugin_manager_parent_class)->dispose (object);
+}
+
+static void
+uca_plugin_manager_finalize (GObject *object)
+{
+    UcaPluginManagerPrivate *priv = UCA_PLUGIN_MANAGER_GET_PRIVATE (object);
+
+    g_list_foreach (priv->search_paths, (GFunc) g_free, NULL);
+    g_list_free (priv->search_paths);
+
+    G_OBJECT_CLASS (uca_plugin_manager_parent_class)->finalize (object);
+}
+
+static void
+uca_plugin_manager_class_init (UcaPluginManagerClass *klass)
+{
+    GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+    gobject_class->get_property = uca_plugin_manager_get_property;
+    gobject_class->set_property = uca_plugin_manager_set_property;
+    gobject_class->dispose      = uca_plugin_manager_dispose;
+    gobject_class->finalize     = uca_plugin_manager_finalize;
+
+    g_type_class_add_private (klass, sizeof (UcaPluginManagerPrivate));
+}
+
+static void
+uca_plugin_manager_init (UcaPluginManager *manager)
+{
+    UcaPluginManagerPrivate *priv;
+
+    manager->priv = priv = UCA_PLUGIN_MANAGER_GET_PRIVATE (manager);
+    priv->search_paths = NULL;
+
+    uca_plugin_manager_add_path (manager, "/usr/lib/uca");
+    uca_plugin_manager_add_path (manager, "/usr/lib64/uca");
+    uca_plugin_manager_add_path (manager, "/usr/local/lib/uca");
+    uca_plugin_manager_add_path (manager, "/usr/local/lib64/uca");
+}