Simplify EPlugin loading at startup.

- Require all EPlugin and EPluginHook subtypes be registered before
  loading plugins.  This drastically simplifies the EPlugin/EPluginHook
  negotiation.

- Turn most EPluginHook subtypes into GTypeModules and register their
  types from an e_module_load() function (does not include shell hooks).

- Convert EPluginLib and the Mono and Python bindings to GTypeModules
  and register their types from an e_module_load() function, and kill
  EPluginTypeHook.

1 files changed, 249 insertions, 0 deletions

diff --git a/modules/plugin-lib/e-plugin-lib.c b/modules/plugin-lib/e-plugin-lib.c
new file mode 100644
index 0000000000..c7a0233bb3
--- /dev/null
+++ b/modules/plugin-lib/e-plugin-lib.c
@@ -0,0 +1,249 @@
+/*
+ * e-plugin-lib.c
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) version 3.
+ *
+ * This program 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with the program; if not, see <http://www.gnu.org/licenses/>
+ *
+ *
+ * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
+ *
+ */
+
+#include "e-plugin-lib.h"
+
+#include <string.h>
+
+static gpointer parent_class;
+static GType plugin_lib_type;
+
+/* TODO:
+   We need some way to manage lifecycle.
+   We need some way to manage state.
+
+   Maybe just the g module init method will do, or we could add
+   another which returns context.
+
+   There is also the question of per-instance context, e.g. for config
+   pages.
+*/
+
+static gint
+plugin_lib_loadmodule (EPlugin *plugin)
+{
+	EPluginLib *plugin_lib = E_PLUGIN_LIB (plugin);
+	EPluginLibEnableFunc enable;
+
+	if (plugin_lib->module != NULL)
+		return 0;
+
+	if (plugin_lib->location == NULL) {
+		g_warning ("Location not set in plugin '%s'", plugin->name);
+		return -1;
+	}
+
+	if ((plugin_lib->module = g_module_open (plugin_lib->location, 0)) == NULL) {
+		g_warning ("can't load plugin '%s': %s", plugin_lib->location, g_module_error ());
+		return -1;
+	}
+
+	if (g_module_symbol (plugin_lib->module, "e_plugin_lib_enable", (gpointer)&enable)) {
+		if (enable (plugin_lib, TRUE) != 0) {
+			plugin->enabled = FALSE;
+			g_module_close (plugin_lib->module);
+			plugin_lib->module = NULL;
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static gpointer
+plugin_lib_invoke (EPlugin *plugin, const gchar *name, gpointer data)
+{
+	EPluginLib *plugin_lib = E_PLUGIN_LIB (plugin);
+	EPluginLibFunc cb;
+
+	if (!plugin->enabled) {
+		g_warning ("trying to invoke '%s' on disabled plugin '%s'", name, plugin->id);
+		return NULL;
+	}
+
+	if (plugin_lib_loadmodule (plugin) != 0)
+		return NULL;
+
+	if (!g_module_symbol (plugin_lib->module, name, (gpointer)&cb)) {
+		g_warning ("Cannot resolve symbol '%s' in plugin '%s' (not exported?)", name, plugin_lib->location);
+		return NULL;
+	}
+
+	return cb (plugin_lib, data);
+}
+
+static gpointer
+plugin_lib_get_symbol (EPlugin *plugin, const gchar *name)
+{
+	EPluginLib *plugin_lib = E_PLUGIN_LIB (plugin);
+	gpointer symbol;
+
+	if (plugin_lib_loadmodule (plugin) != 0)
+		return NULL;
+
+	if (!g_module_symbol (plugin_lib->module, name, &symbol))
+		return NULL;
+
+	return symbol;
+}
+
+static gint
+plugin_lib_construct (EPlugin *plugin, xmlNodePtr root)
+{
+	EPluginLib *plugin_lib = E_PLUGIN_LIB (plugin);
+
+	/* Set the location before chaining up, as some EPluginHooks
+	 * will cause the module to load during hook construction. */
+
+	plugin_lib->location = e_plugin_xml_prop (root, "location");
+
+	if (plugin_lib->location == NULL) {
+		g_warning ("Library plugin '%s' has no location", plugin->id);
+		return -1;
+	}
+#ifdef G_OS_WIN32
+	{
+		gchar *mapped_location =
+			e_util_rplugin_libace_prefix (EVOLUTION_PREFIX,
+					       e_util_get_prefix (),
+					       plugin_lib->location);
+		g_free (plugin_lib->location);
+		plugin_lib->location = mapped_location;
+	}
+#endif
+
+	/* Chain up to parent's construct() method. */
+	if (E_PLUGIN_CLASS (parent_class)->construct (plugin, root) == -1)
+		return -1;
+
+	/* If we're enabled, check for the load-on-startup property */
+	if (plugin->enabled) {
+		xmlChar *tmp;
+
+		tmp = xmlGetProp (root, (const guchar *)"load-on-startup");
+		if (tmp) {
+			if (plugin_lib_loadmodule (plugin) != 0) {
+				xmlFree (tmp);
+				return -1;
+			}
+			xmlFree (tmp);
+		}
+	}
+
+	return 0;
+}
+
+static GtkWidget *
+plugin_lib_get_configure_widget (EPlugin *plugin)
+{
+	EPluginLib *plugin_lib = E_PLUGIN_LIB (plugin);
+	EPluginLibGetConfigureWidgetFunc get_configure_widget;
+
+	if (plugin_lib_loadmodule (plugin) != 0) {
+		return NULL;
+	}
+
+	if (g_module_symbol (plugin_lib->module, "e_plugin_lib_get_configure_widget", (gpointer)&get_configure_widget)) {
+		return (GtkWidget*) get_configure_widget (plugin_lib);
+	}
+	return NULL;
+}
+
+static void
+plugin_lib_enable (EPlugin *plugin, gint state)
+{
+	EPluginLib *plugin_lib = E_PLUGIN_LIB (plugin);
+	EPluginLibEnableFunc enable;
+
+	E_PLUGIN_CLASS (parent_class)->enable (plugin, state);
+
+	/* if we're disabling and it isn't loaded, nothing to do */
+	if (!state && plugin_lib->module == NULL)
+		return;
+
+	/* this will noop if we're disabling since we tested it above */
+	if (plugin_lib_loadmodule (plugin) != 0)
+		return;
+
+	if (g_module_symbol (plugin_lib->module, "e_plugin_lib_enable", (gpointer) &enable)) {
+		if (enable (plugin_lib, state) != 0)
+			return;
+	}
+}
+
+static void
+plugin_lib_finalize (GObject *object)
+{
+	EPluginLib *plugin_lib = E_PLUGIN_LIB (object);
+
+	g_free (plugin_lib->location);
+
+	if (plugin_lib->module)
+		g_module_close (plugin_lib->module);
+
+	/* Chain up to parent's finalize() method. */
+	G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+plugin_lib_class_init (EPluginClass *class)
+{
+	GObjectClass *object_class;
+
+	parent_class = g_type_class_peek_parent (class);
+
+	object_class = G_OBJECT_CLASS (class);
+	object_class->finalize = plugin_lib_finalize;
+
+	class->construct = plugin_lib_construct;
+	class->invoke = plugin_lib_invoke;
+	class->get_symbol = plugin_lib_get_symbol;
+	class->enable = plugin_lib_enable;
+	class->get_configure_widget = plugin_lib_get_configure_widget;
+	class->type = "shlib";
+}
+
+GType
+e_plugin_lib_get_type (void)
+{
+	return plugin_lib_type;
+}
+
+void
+e_plugin_lib_register_type (GTypeModule *type_module)
+{
+	static const GTypeInfo type_info = {
+		sizeof (EPluginLibClass),
+		(GBaseInitFunc) NULL,
+		(GBaseFinalizeFunc) NULL,
+		(GClassInitFunc) plugin_lib_class_init,
+		(GClassFinalizeFunc) NULL,
+		NULL,  /* class_data */
+		sizeof (EPluginLib),
+		0,     /* n_preallocs */
+		(GInstanceInitFunc) NULL,
+		NULL   /* value_table */
+	};
+
+	plugin_lib_type = g_type_module_register_type (
+		type_module, E_TYPE_PLUGIN,
+		"EPluginLib", &type_info, 0);
+}