path: root/e-util/e-plugin-ui.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * Copyright (C) 2008 Novell, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU Lesser General Public
 * License as published by the Free Software Foundation.
 *
 * 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "e-plugin-ui.h"

#include <string.h>

#define E_PLUGIN_UI_HOOK_GET_PRIVATE(obj) \
    (G_TYPE_INSTANCE_GET_PRIVATE \
    ((obj), E_TYPE_PLUGIN_UI_HOOK, EPluginUIHookPrivate))

#define E_PLUGIN_UI_INIT_FUNC       "e_plugin_ui_init"
#define E_PLUGIN_UI_HOOK_CLASS_ID       "org.gnome.evolution.ui:1.0"
#define E_PLUGIN_UI_MANAGER_ID_KEY  "e-plugin-ui-manager-id"

struct _EPluginUIHookPrivate {

    /* Table of GtkUIManager ID's to UI definitions. 
     *
     * For example:
     *
     *     <ui-manager id="org.gnome.evolution.sample">
     *             ... UI definition ...
     *     </ui-manager>
     *
     * Results in:
     *
     *     g_hash_table_insert (
     *             ui_definitions,
     *             "org.gnome.evolution.sample",
     *             "... UI definition ...");
     *
     * See http://library.gnome.org/devel/gtk/unstable/GtkUIManager.html
     * for more information about UI definitions.  Note: the <ui> tag is
     * optional.
     */
    GHashTable *ui_definitions;
};

/* The registry is a hash table of hash tables.  It maps
 *
 *    EPluginUIHook instance --> GtkUIManager instance --> UI merge id
 *
 * GtkUIManager instances are automatically removed when finalized.
 */
static GHashTable *registry;
static gpointer parent_class;

static void
plugin_ui_registry_remove (EPluginUIHook *hook,
                           GtkUIManager *manager)
{
    GHashTable *hash_table;

    /* Note: Manager may already be finalized. */

    hash_table = g_hash_table_lookup (registry, hook);
    g_return_if_fail (hash_table != NULL);

    g_hash_table_remove (hash_table, manager);
    if (g_hash_table_size (hash_table) == 0)
        g_hash_table_remove (registry, hook);
}

static void
plugin_ui_registry_insert (EPluginUIHook *hook,
                           GtkUIManager *manager,
                           guint merge_id)
{
    GHashTable *hash_table;

    if (registry == NULL)
        registry = g_hash_table_new_full (
            g_direct_hash, g_direct_equal,
            (GDestroyNotify) NULL,
            (GDestroyNotify) g_hash_table_destroy);

    hash_table = g_hash_table_lookup (registry, hook);
    if (hash_table == NULL) {
        hash_table = g_hash_table_new (g_direct_hash, g_direct_equal);
        g_hash_table_insert (registry, hook, hash_table);
    }

    g_object_weak_ref (
        G_OBJECT (manager), (GWeakNotify)
        plugin_ui_registry_remove, hook);

    g_hash_table_insert (hash_table, manager, GUINT_TO_POINTER (merge_id));
}

/* Helper for plugin_ui_hook_merge_ui() */
static void
plugin_ui_hook_merge_foreach (GtkUIManager *manager,
                              const gchar *ui_definition,
                              GHashTable *hash_table)
{
    guint merge_id;
    GError *error = NULL;

    /* Merge the UI definition into the manager. */
    merge_id = gtk_ui_manager_add_ui_from_string (
        manager, ui_definition, -1, &error);
    gtk_ui_manager_ensure_update (manager);
    if (error != NULL) {
        g_warning ("%s", error->message);
        g_error_free (error);
    }

    /* Merge ID will be 0 on error, which is what we want. */
    g_hash_table_insert (hash_table, manager, GUINT_TO_POINTER (merge_id));
}

static void
plugin_ui_hook_merge_ui (EPluginUIHook *hook)
{
    GHashTable *old_merge_ids;
    GHashTable *new_merge_ids;
    GHashTable *intermediate;
    GList *keys;

    old_merge_ids = g_hash_table_lookup (registry, hook);
    if (old_merge_ids == NULL)
        return;

    /* The GtkUIManager instances and UI definitions live in separate
     * tables, so we need to build an intermediate table that we can
     * easily iterate over. */
    keys = g_hash_table_get_keys (old_merge_ids);
    intermediate = g_hash_table_new (g_direct_hash, g_direct_equal);

    while (keys != NULL) {
        GtkUIManager *manager = keys->data;
        gchar *ui_definition;

        ui_definition = g_hash_table_lookup (
            hook->priv->ui_definitions,
            e_plugin_ui_get_manager_id (manager));

        g_hash_table_insert (intermediate, manager, ui_definition);

        keys = g_list_delete_link (keys, keys);
    }

    new_merge_ids = g_hash_table_new (g_direct_hash, g_direct_equal);

    g_hash_table_foreach (
        intermediate, (GHFunc)
        plugin_ui_hook_merge_foreach, new_merge_ids);

    g_hash_table_insert (registry, hook, new_merge_ids);

    g_hash_table_destroy (intermediate);
}

/* Helper for plugin_ui_hook_unmerge_ui() */
static void
plugin_ui_hook_unmerge_foreach (GtkUIManager *manager,
                                gpointer value,
                                GHashTable *hash_table)
{
    guint merge_id;

    merge_id = GPOINTER_TO_UINT (value);
    gtk_ui_manager_remove_ui (manager, merge_id);

    g_hash_table_insert (hash_table, manager, GUINT_TO_POINTER (0));
}

static void
plugin_ui_hook_unmerge_ui (EPluginUIHook *hook)
{
    GHashTable *old_merge_ids;
    GHashTable *new_merge_ids;

    old_merge_ids = g_hash_table_lookup (registry, hook);
    if (old_merge_ids == NULL)
        return;

    new_merge_ids = g_hash_table_new (g_direct_hash, g_direct_equal);

    g_hash_table_foreach (
        old_merge_ids, (GHFunc)
        plugin_ui_hook_unmerge_foreach, new_merge_ids);

    g_hash_table_insert (registry, hook, new_merge_ids);
}

static void
plugin_ui_hook_register_manager (EPluginUIHook *hook,
                                 GtkUIManager *manager,
                                 const gchar *ui_definition,
                                 gpointer user_data)
{
    EPlugin *plugin;
    EPluginUIInitFunc func;
    guint merge_id = 0;

    plugin = ((EPluginHook *) hook)->plugin;
    func = e_plugin_get_symbol (plugin, E_PLUGIN_UI_INIT_FUNC);

    /* Pass the manager and user_data to the plugin's e_plugin_ui_init()
     * function (if it defined one).  The plugin should install whatever
     * GtkActions and GtkActionGroups are neccessary to implement the
     * action names in its UI definition. */
    if (func != NULL && !func (manager, user_data))
        return;

    if (plugin->enabled) {
        GError *error = NULL;

        /* Merge the UI definition into the manager. */
        merge_id = gtk_ui_manager_add_ui_from_string (
            manager, ui_definition, -1, &error);
        gtk_ui_manager_ensure_update (manager);
        if (error != NULL) {
            g_warning ("%s", error->message);
            g_error_free (error);
        }
    }

    /* Save merge ID's for later use. */
    plugin_ui_registry_insert (hook, manager, merge_id);
}

static void
plugin_ui_hook_finalize (GObject *object)
{
    EPluginUIHookPrivate *priv;

    priv = E_PLUGIN_UI_HOOK_GET_PRIVATE (object);

    g_hash_table_destroy (priv->ui_definitions);

    /* Chain up to parent's dispose() method. */
    G_OBJECT_CLASS (parent_class)->dispose (object);
}

static gint
plugin_ui_hook_construct (EPluginHook *hook,
                          EPlugin *plugin,
                          xmlNodePtr node)
{
    EPluginUIHookPrivate *priv;

    priv = E_PLUGIN_UI_HOOK_GET_PRIVATE (hook);

    /* XXX The EPlugin should be a property of EPluginHookClass.
     *     Then it could be passed directly to g_object_new() and
     *     we wouldn't have to chain up here. */

    /* Chain up to parent's construct() method. */
    E_PLUGIN_HOOK_CLASS (parent_class)->construct (hook, plugin, node);

    for (node = node->children; node != NULL; node = node->next) {
        xmlNodePtr child;
        xmlBufferPtr buffer;
        const gchar *content;
        gchar *id;

        if (strcmp ((gchar *) node->name, "ui-manager") != 0)
            continue;

        id = e_plugin_xml_prop (node, "id");
        if (id == NULL) {
            g_warning ("<ui-manager> requires 'id' property");
            continue;
        }

        /* Extract the XML content below <ui-manager> */
        buffer = xmlBufferCreate ();
        child = node->children;
        while (child != NULL && xmlNodeIsText (child))
            child = child->next;
        if (child != NULL)
            xmlNodeDump (buffer, node->doc, child, 2, 1);
        content = (const gchar *) xmlBufferContent (buffer);

        g_hash_table_insert (
            priv->ui_definitions,
            id, g_strdup (content));

        xmlBufferFree (buffer);
    }

    return 0;
}

static void
plugin_ui_hook_enable (EPluginHook *hook,
                       gint state)
{
    if (state)
        plugin_ui_hook_merge_ui (E_PLUGIN_UI_HOOK (hook));
    else
        plugin_ui_hook_unmerge_ui (E_PLUGIN_UI_HOOK (hook));
}

static void
plugin_ui_hook_class_init (EPluginUIHookClass *class)
{
    GObjectClass *object_class;
    EPluginHookClass *plugin_hook_class;

    parent_class = g_type_class_peek_parent (class);
    g_type_class_add_private (class, sizeof (EPluginUIHookPrivate));

    object_class = G_OBJECT_CLASS (class);
    object_class->finalize = plugin_ui_hook_finalize;

    plugin_hook_class = E_PLUGIN_HOOK_CLASS (class);
    plugin_hook_class->id = E_PLUGIN_UI_HOOK_CLASS_ID;
    plugin_hook_class->construct = plugin_ui_hook_construct;
    plugin_hook_class->enable = plugin_ui_hook_enable;
}

static void
plugin_ui_hook_init (EPluginUIHook *hook)
{
    GHashTable *ui_definitions;

    ui_definitions = g_hash_table_new_full (
        g_str_hash, g_str_equal,
        (GDestroyNotify) g_free,
        (GDestroyNotify) g_free);

    hook->priv = E_PLUGIN_UI_HOOK_GET_PRIVATE (hook);
    hook->priv->ui_definitions = ui_definitions;
}

GType
e_plugin_ui_hook_get_type (void)
{
    static GType type = 0;

    if (G_UNLIKELY (type == 0)) {
        static const GTypeInfo type_info = {
            sizeof (EPluginUIHookClass),
            (GBaseInitFunc) NULL,
            (GBaseFinalizeFunc) NULL,
            (GClassInitFunc) plugin_ui_hook_class_init,
            (GClassFinalizeFunc) NULL,
            NULL,  /* class_data */
            sizeof (EPluginUIHook),
            0,     /* n_preallocs */
            (GInstanceInitFunc) plugin_ui_hook_init,
            NULL   /* value_table */
        };

        type = g_type_register_static (
            E_TYPE_PLUGIN_HOOK, "EPluginUIHook", &type_info, 0);
    }

    return type;
}

void
e_plugin_ui_register_manager (const gchar *id,
                              GtkUIManager *manager,
                              gpointer user_data)
{
    const gchar *key = E_PLUGIN_UI_MANAGER_ID_KEY;
    GSList *plugin_list;

    g_return_if_fail (id != NULL);
    g_return_if_fail (GTK_IS_UI_MANAGER (manager));

    g_object_set_data (G_OBJECT (manager), key, (gpointer) id);

    /* Loop over all installed plugins. */
    plugin_list = e_plugin_list_plugins ();
    while (plugin_list != NULL) {
        EPlugin *plugin = plugin_list->data;
        GSList *iter;

        /* Look for hooks of type EPluginUIHook. */
        for (iter = plugin->hooks; iter != NULL; iter = iter->next) {
            EPluginUIHook *hook = iter->data;
            const gchar *ui_definition;

            if (!E_IS_PLUGIN_UI_HOOK (hook))
                continue;

            /* Check if the hook has a UI definition
             * for the GtkUIManager being registered. */
            ui_definition = g_hash_table_lookup (
                hook->priv->ui_definitions, id);
            if (ui_definition == NULL)
                continue;

            /* Register the manager with the hook. */
            plugin_ui_hook_register_manager (
                hook, manager, ui_definition, user_data);
        }

        plugin_list = g_slist_next (plugin_list);
    }
}

const gchar *
e_plugin_ui_get_manager_id (GtkUIManager *manager)
{
    const gchar *key = E_PLUGIN_UI_MANAGER_ID_KEY;

    g_return_val_if_fail (GTK_IS_UI_MANAGER (manager), NULL);

    return g_object_get_data (G_OBJECT (manager), key);
}