path: root/modules/plugin-lib/e-plugin-lib.c

/*
 * 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)
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "e-plugin-lib.h"

#ifdef G_OS_WIN32
#include <libedataserver/e-data-server-util.h> /* for e_util_replace_prefix() */
#endif

#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;
    gboolean found_symbol;

    if (plugin_lib->module != NULL)
        return 0;

    if (plugin_lib->location == NULL) {
        plugin->enabled = FALSE;
        g_warning ("Location not set in plugin '%s'", plugin->name);
        return -1;
    }

    plugin_lib->module = g_module_open (plugin_lib->location, 0);

    if (plugin_lib->module == NULL) {
        plugin->enabled = FALSE;
        g_warning (
            "can't load plugin '%s': %s",
            plugin_lib->location, g_module_error ());
        return -1;
    }

    /* If the plugin is disabled, we're done. */
    if (!plugin->enabled)
        return 0;

    found_symbol = g_module_symbol (
        plugin_lib->module,
        "e_plugin_lib_enable",
        (gpointer) &enable);

    if (found_symbol) {
        if (enable (plugin, TRUE) != 0) {
            plugin->enabled = FALSE;
            g_module_close (plugin_lib->module);
            plugin_lib->module = NULL;
            return -1;
        }
    }

    return 0;
}

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 gpointer
plugin_lib_invoke (EPlugin *plugin,
                   const gchar *name,
                   gpointer data)
{
    EPluginLib *plugin_lib = E_PLUGIN_LIB (plugin);
    EPluginLibFunc func;

    if (!plugin->enabled) {
        g_warning (
            "Trying to invoke '%s' on disabled plugin '%s'",
            name, plugin->id);
        return NULL;
    }

    func = plugin_lib_get_symbol (plugin, name);

    if (func == NULL) {
        g_warning (
            "Cannot resolve symbol '%s' in plugin '%s' "
            "(not exported?)", name, plugin_lib->location);
        return NULL;
    }

    return func (plugin, data);
}

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_replace_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)
{
    EPluginLibGetConfigureWidgetFunc get_configure_widget;

    get_configure_widget = plugin_lib_get_symbol (
        plugin, "e_plugin_lib_get_configure_widget");

    if (get_configure_widget != NULL)
        return get_configure_widget (plugin);

    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;

    enable = plugin_lib_get_symbol (plugin, "e_plugin_lib_enable");

    if (enable != NULL)
        enable (plugin, state);
}

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);
}