path: root/src/ephy-extensions-manager.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 *  Copyright © 2003 Marco Pesenti Gritti
 *  Copyright © 2003, 2004 Christian Persch
 *  Copyright © 2004 Adam Hooper
 *  Copyright © 2005 Crispin Flowerday
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  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 General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"

#include "ephy-extensions-manager.h"

#include "ephy-loader.h"
#include "ephy-shlib-loader.h"

#include "ephy-embed-container.h"

#include "ephy-node-db.h"
#include "ephy-shell.h"
#include "eel-gconf-extensions.h"
#include "ephy-file-helpers.h"
#include "ephy-object-helpers.h"
#include "ephy-debug.h"

#include <libxml/tree.h>
#include <libxml/xmlreader.h>
#include <libxml/globals.h>
#include <libxml/tree.h>
#include <libxml/xmlwriter.h>
#include <libxslt/xslt.h>
#include <libxslt/transform.h>
#include <libxslt/xsltutils.h>

#include <gconf/gconf-client.h>

#include <gio/gio.h>
#include <gmodule.h>
#include <dirent.h>
#include <string.h>

#ifdef ENABLE_SEED
#include "ephy-seed-loader.h"
#endif

#define CONF_LOADED_EXTENSIONS  "/apps/epiphany/general/active_extensions"
#define EE_GROUP        "Epiphany Extension"
#define DOT_INI         ".ephy-extension"
#define RELOAD_DELAY        333 /* ms */
#define RELOAD_SYNC_DELAY   1 /* seconds */

#define ENABLE_LEGACY_FORMAT

#define EPHY_EXTENSIONS_MANAGER_GET_PRIVATE(object)(G_TYPE_INSTANCE_GET_PRIVATE ((object), EPHY_TYPE_EXTENSIONS_MANAGER, EphyExtensionsManagerPrivate))

struct _EphyExtensionsManagerPrivate
{
    gboolean initialised;

    GList *data;
    GList *factories;
    GList *extensions;
    GList *dir_monitors;
    GList *windows;
    guint active_extensions_notifier_id;
    guint sync_timeout_id;
    GHashTable *reload_hash;

#ifdef ENABLE_LEGACY_FORMAT
    xsltStylesheetPtr xml2ini_xsl;
#endif
};

typedef struct
{
    EphyExtensionInfo info;
    gboolean load_failed;

    char *loader_type;

    EphyLoader *loader; /* NULL if never loaded */
    GObject *extension; /* NULL if unloaded */

#ifdef ENABLE_LEGACY_FORMAT
    guint is_legacy_format : 1;
#endif
} ExtensionInfo;

typedef struct
{
    char *type;
    EphyLoader *loader;
} LoaderInfo;

typedef enum
{
    FORMAT_UNKNOWN,
    FORMAT_INI
#ifdef ENABLE_LEGACY_FORMAT
    , FORMAT_XML
#endif
} ExtensionFormat;

enum
{
    CHANGED,
    ADDED,
    REMOVED,
    LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = { 0 };

static void ephy_extensions_manager_class_init  (EphyExtensionsManagerClass *klass);
static void ephy_extensions_manager_iface_init  (EphyExtensionIface *iface);
static void ephy_extensions_manager_init    (EphyExtensionsManager *manager);

G_DEFINE_TYPE_WITH_CODE (EphyExtensionsManager, ephy_extensions_manager, G_TYPE_OBJECT,
             G_IMPLEMENT_INTERFACE (EPHY_TYPE_EXTENSION,
                        ephy_extensions_manager_iface_init))

/**
 * ephy_extensions_manager_load:
 * @manager: an #EphyExtensionsManager
 * @identifier: identifier of the extension to load
 *
 * Loads the extension corresponding to @identifier.
 **/
void
ephy_extensions_manager_load (EphyExtensionsManager *manager,
                  const char *identifier)
{
    GSList *gconf_exts;

    g_return_if_fail (EPHY_IS_EXTENSIONS_MANAGER (manager));
    g_return_if_fail (identifier != NULL);

    LOG ("Adding '%s' to extensions", identifier);

    gconf_exts = eel_gconf_get_string_list (CONF_LOADED_EXTENSIONS);

    if (!g_slist_find_custom (gconf_exts, identifier, (GCompareFunc) strcmp))
    {
        gconf_exts = g_slist_prepend (gconf_exts, g_strdup (identifier));

        eel_gconf_set_string_list (CONF_LOADED_EXTENSIONS, gconf_exts);
    }

    g_slist_foreach (gconf_exts, (GFunc) g_free, NULL);
    g_slist_free (gconf_exts);
}

/**
 * ephy_extensions_manager_unload:
 * @manager: an #EphyExtensionsManager
 * @identifier: filename of extension to unload, minus "lib" and "extension.so"
 *
 * Unloads the extension specified by @identifier.
 *
 * The extension with the same filename can afterwards be reloaded. However,
 * if any GTypes within the extension have changed parent types, Epiphany must
 * be restarted.
 **/
void
ephy_extensions_manager_unload (EphyExtensionsManager *manager,
                const char *identifier)
{
    GSList *gconf_exts;
    GSList *l;

    g_return_if_fail (EPHY_IS_EXTENSIONS_MANAGER (manager));
    g_return_if_fail (identifier != NULL);

    LOG ("Removing '%s' from extensions", identifier);

    gconf_exts = eel_gconf_get_string_list (CONF_LOADED_EXTENSIONS);

    l = g_slist_find_custom (gconf_exts, identifier, (GCompareFunc) strcmp);

    if (l != NULL)
    {
        gconf_exts = g_slist_remove_link (gconf_exts, l);
        g_free (l->data);
        g_slist_free_1 (l);

        eel_gconf_set_string_list (CONF_LOADED_EXTENSIONS, gconf_exts);
    }

    g_slist_foreach (gconf_exts, (GFunc) g_free, NULL);
    g_slist_free (gconf_exts);
}

/**
 * ephy_extensions_manager_register:
 * @manager: an #EphyExtensionsManager
 * @object: an Extension
 *
 * Registers @object with the extensions manager. @object must implement the
 * #EphyExtension interface.
 **/
void
ephy_extensions_manager_register (EphyExtensionsManager *manager,
                  GObject *object)
{
    g_return_if_fail (EPHY_IS_EXTENSIONS_MANAGER (manager));
    g_return_if_fail (EPHY_IS_EXTENSION (object));

    manager->priv->extensions = g_list_prepend (manager->priv->extensions,
                            g_object_ref (object));
}


/**
 * ephy_extensions_manager_get_extensions:
 * @manager: an #EphyExtensionsManager
 *
 * Returns the list of known extensions.
 *
 * Returns: (element-type EphyEmbed) (transfer container): a list of
 *          #EphyExtensionInfo
 **/
GList *
ephy_extensions_manager_get_extensions (EphyExtensionsManager *manager)
{
    return g_list_copy (manager->priv->data);
}

static void
free_extension_info (ExtensionInfo *info)
{
    EphyExtensionInfo *einfo = (EphyExtensionInfo *) info;

    g_free (einfo->identifier);
    g_key_file_free (einfo->keyfile);
    g_free (info->loader_type);

    if (info->extension != NULL)
    {
        g_return_if_fail (info->loader != NULL);

        ephy_loader_release_object (info->loader, info->extension);
    }
    if (info->loader != NULL)
    {
        g_object_unref (info->loader);
    }

    g_free (info);
}

static void
free_loader_info (LoaderInfo *info)
{
    g_free (info->type);
    g_object_unref (info->loader);
    g_free (info);
}

static int
find_extension_info (const ExtensionInfo *info,
             const char *identifier)
{
    return strcmp (info->info.identifier, identifier);
}

static ExtensionInfo *
ephy_extensions_manager_parse_keyfile (EphyExtensionsManager *manager,
                       GKeyFile *key_file,
                       const char *identifier)
{
    ExtensionInfo *info;
    EphyExtensionInfo *einfo;
    char *start_group;

    LOG ("Parsing INI description file for '%s'", identifier);

    start_group = g_key_file_get_start_group (key_file);
    if (start_group == NULL ||
        strcmp (start_group, EE_GROUP) != 0 ||
        !g_key_file_has_group (key_file, "Loader"))
    {
        g_warning ("Invalid extension description file for '%s'; "
               "missing 'Epiphany Extension' or 'Loader' group",
               identifier);
        
        g_key_file_free (key_file);
        g_free (start_group);
        return NULL;
    }
    g_free (start_group);

    if (!g_key_file_has_key (key_file, EE_GROUP, "Name", NULL) ||
        !g_key_file_has_key (key_file, EE_GROUP, "Description", NULL))
    {
        g_warning ("Invalid extension description file for '%s'; "
               "missing 'Name' or 'Description' keys.",
               identifier);
        
        g_key_file_free (key_file);
        return NULL;
    }

    info = g_new0 (ExtensionInfo, 1);
    einfo = (EphyExtensionInfo *) info;
    einfo->identifier = g_strdup (identifier);
    einfo->keyfile = key_file;

    info->loader_type = g_key_file_get_string (key_file, "Loader", "Type", NULL);

    /* sanity check */
    if (info->loader_type == NULL || info->loader_type[0] == '\0')
    {
        free_extension_info (info);
        return NULL;
    }

    manager->priv->data = g_list_prepend (manager->priv->data, info);

    g_signal_emit (manager, signals[ADDED], 0, info);

    return info;
}

static void
ephy_extensions_manager_load_ini_file (EphyExtensionsManager *manager,
                       const char *identifier,
                       const char *path)
{
    GKeyFile *keyfile;
    GError *err = NULL;

    keyfile = g_key_file_new ();
    if (!g_key_file_load_from_file (keyfile, path, G_KEY_FILE_NONE, &err))
    {
        g_warning ("Could load key file for '%s': '%s'",
               identifier, err->message);
        g_error_free (err);
        g_key_file_free (keyfile);
        return;
    }

    ephy_extensions_manager_parse_keyfile (manager, keyfile, identifier);
}

#ifdef ENABLE_LEGACY_FORMAT

static void
ephy_extensions_manager_load_xml_file (EphyExtensionsManager *manager,
                       const char *identifier,
                       const char *path)
{
    EphyExtensionsManagerPrivate *priv = manager->priv;
    ExtensionInfo *info;
    xmlDocPtr doc, res;
    const xmlChar *xsl_file;
    xmlChar *output = NULL;
    int outlen = -1, ret = -1;
    
    START_PROFILER ("Transforming .xml -> " DOT_INI)

    doc = xmlParseFile (path);
    if (!doc) goto out;

    if (priv->xml2ini_xsl == NULL)
    {
        xsl_file = (const xmlChar *) ephy_file ("ephy-xml2ini.xsl");
        if (!xsl_file) return;

        priv->xml2ini_xsl = xsltParseStylesheetFile (xsl_file);
        if (priv->xml2ini_xsl == NULL)
        {
            g_warning ("Couldn't parse the XSL to transform .xml extension descriptions!\n");
            goto out;
        }
    }

    res = xsltApplyStylesheet (priv->xml2ini_xsl, doc, NULL);
    if (!res) goto out;

    ret = xsltSaveResultToString (&output, &outlen, res, priv->xml2ini_xsl);

    if (ret >= 0 && output != NULL && outlen > -1)
    {
        GKeyFile *keyfile;
        GError *err = NULL;

        keyfile = g_key_file_new ();
        if (!g_key_file_load_from_data (keyfile, (char *) output, outlen,
                            G_KEY_FILE_NONE, &err))
        {
            g_warning ("Could load converted key file for '%s': '%s'",
                   identifier, err->message);
            g_error_free (err);
            g_key_file_free (keyfile);
            goto out;
        }

        info = ephy_extensions_manager_parse_keyfile (manager, keyfile, identifier);
        if (info != NULL)
        {
            info->is_legacy_format = TRUE;
        }
    }

    xmlFreeDoc (res);
    xmlFreeDoc (doc);

out:
    xmlFree (output);

    STOP_PROFILER ("Transforming .xml -> " DOT_INI)
}

#endif /* ENABLE_LEGACY_FORMAT */

static char *
path_to_identifier (const char *path)
{
    char *identifier, *dot;

    identifier = g_path_get_basename (path);
    dot = strstr (identifier, DOT_INI);

#ifdef ENABLE_LEGACY_FORMAT
    if (!dot)
    {
        dot = strstr (identifier, ".xml");
    }
#endif

    g_return_val_if_fail (dot != NULL, NULL);

    *dot = '\0';

    return identifier;
}

static ExtensionFormat
format_from_path (const char *path)
{
    ExtensionFormat format = FORMAT_UNKNOWN;

    if (g_str_has_suffix (path, DOT_INI))
    {
        format = FORMAT_INI;
    }
#ifdef ENABLE_LEGACY_FORMAT
    else if (g_str_has_suffix (path, ".xml"))
    {
        format = FORMAT_XML;
    }
#endif

    return format;
}

static void
ephy_extensions_manager_load_file (EphyExtensionsManager *manager,
                   const char *path)
{
    GList *element;
    char *identifier;
    ExtensionFormat format;

    identifier = path_to_identifier (path);
    g_return_if_fail (identifier != NULL);
    if (identifier == NULL) return;

    format = format_from_path (path);
    g_return_if_fail (format != FORMAT_UNKNOWN);

    element = g_list_find_custom (manager->priv->data, identifier,
                      (GCompareFunc) find_extension_info);
    if (element != NULL)
    {
#ifdef ENABLE_LEGACY_FORMAT
        ExtensionInfo *info = (ExtensionInfo *) element->data;

        /* If this is the legacy format and we already have the info
         * read for this type from a non-legacy format file, don't
         * warn.
         */
        if (format == FORMAT_XML && !info->is_legacy_format)
#endif
        {
            g_warning ("Extension description for '%s' already read!",
                   identifier);
        }

        g_free (identifier);
        return;
    }

    if (format == FORMAT_INI)
    {
        ephy_extensions_manager_load_ini_file (manager, identifier,
                               path);
    }
#ifdef ENABLE_LEGACY_FORMAT
    else if (format == FORMAT_XML)
    {
        ephy_extensions_manager_load_xml_file (manager, identifier,
                               path);
    }
#endif

    g_free (identifier);
}


static int
find_loader (const LoaderInfo *info,
          const char *type)
{
    return strcmp (info->type, type);
}

static char *
sanitise_type (const char *string)
{
    char *str, *p;

    str = g_strdup (string);
    for (p = str; *p != '\0'; p++)
    {
        if (!g_ascii_isalpha (*p)) *p = '-';
    }

    return str;
}

static EphyLoader *
get_loader_for_type (EphyExtensionsManager *manager,
             const char *type)
{
    LoaderInfo *info;
    GList *l;
    char *path, *name, *stype, *data;
    GKeyFile *keyfile;
    EphyLoader *shlib_loader;
    GObject *loader;

    LOG ("Looking for loader for type '%s'", type);

    l = g_list_find_custom (manager->priv->factories, type,
                (GCompareFunc) find_loader);
    if (l != NULL)
    {
        info = (LoaderInfo *) l->data;
        return g_object_ref (info->loader);
    }

    if (strcmp (type, "shlib") == 0)
    {
        info = g_new (LoaderInfo, 1);
        info->type = g_strdup (type);
        info->loader = g_object_new (EPHY_TYPE_SHLIB_LOADER, NULL);

        manager->priv->factories =
            g_list_append (manager->priv->factories, info);

        return g_object_ref (info->loader);
    }
    if (strcmp (type, "python") == 0)
    {
        return NULL;
    }

#ifdef ENABLE_SEED
    if (strcmp (type, "seed") == 0)
    {
        info = g_new (LoaderInfo, 1);
        info->type = g_strdup (type);
        info->loader = g_object_new (EPHY_TYPE_SEED_LOADER, NULL);

        manager->priv->factories =
                g_list_append (manager->priv->factories, info);

        return g_object_ref (info->loader);
        return NULL;
    }
#endif
    shlib_loader = get_loader_for_type (manager, "shlib");
    g_return_val_if_fail (shlib_loader != NULL, NULL);

    stype = sanitise_type (type);
    name = g_strconcat ("lib", stype, "loader.", G_MODULE_SUFFIX, NULL);
    path = g_build_filename (LOADER_DIR, name, NULL);
    data = g_strconcat ("[Loader]\nType=shlib\nLibrary=", path, "\n", NULL);
    g_free (stype);
    g_free (name);
    g_free (path);

    keyfile = g_key_file_new ();
    if (!g_key_file_load_from_data (keyfile, data, strlen (data), 0, NULL))
    {
        g_free (data);
        return NULL;
    }

    loader = ephy_loader_get_object (shlib_loader, keyfile);
    g_key_file_free (keyfile);

    if (EPHY_IS_LOADER (loader))
    {
        info = g_new (LoaderInfo, 1);
        info->type = g_strdup (type);
        info->loader = EPHY_LOADER (loader);

        manager->priv->factories =
            g_list_append (manager->priv->factories, info);

        return g_object_ref (info->loader);
    }

    g_return_val_if_reached (NULL);

    return NULL;
}

static void
attach_window (EphyWindow *window,
           EphyExtension *extension)
{
    GList *tabs, *l;

    ephy_extension_attach_window (extension, window);

    tabs = ephy_embed_container_get_children 
          (EPHY_EMBED_CONTAINER (window));
    for (l = tabs; l; l = l->next)
    {
        ephy_extension_attach_tab (extension, window,
                       EPHY_EMBED (l->data));
    }
    g_list_free (tabs);
}

static void
load_extension (EphyExtensionsManager *manager,
        ExtensionInfo *info)
{
    EphyLoader *loader;

    g_return_if_fail (info->extension == NULL);

    LOG ("Loading extension '%s'", info->info.identifier);

    /* don't try again */
    if (info->load_failed) return;

    /* get a loader */
    loader = get_loader_for_type (manager, info->loader_type);
    if (loader == NULL)
    {
        g_message ("No loader found for extension '%s' of type '%s'\n",
               info->info.identifier, info->loader_type);
        return;
    }

    info->loader = loader;

    info->extension = ephy_loader_get_object (loader, info->info.keyfile);

    /* attach if the extension implements EphyExtensionIface */
    if (EPHY_IS_EXTENSION (info->extension))
    {
        manager->priv->extensions =
            g_list_prepend (manager->priv->extensions,
                    g_object_ref (info->extension));

        g_list_foreach (manager->priv->windows, (GFunc) attach_window,
                info->extension);
    }

    if (info->extension != NULL)
    {
        info->info.active = TRUE;
    }
    else
    {
        info->info.active = FALSE;
        info->load_failed = TRUE;
    }
}

static void
detach_window (EphyWindow *window,
           EphyExtension *extension)
{
    GList *tabs, *l;

    tabs = ephy_embed_container_get_children 
          (EPHY_EMBED_CONTAINER (window));
    for (l = tabs; l; l = l->next)
    {
        ephy_extension_detach_tab (extension, window,
                       EPHY_EMBED (l->data));
    }
    g_list_free (tabs);

    ephy_extension_detach_window (extension, window);
}

static void
unload_extension (EphyExtensionsManager *manager,
          ExtensionInfo *info)
{
    g_return_if_fail (info->loader != NULL);
    g_return_if_fail (info->extension != NULL || info->load_failed);

    LOG ("Unloading extension '%s'", info->info.identifier);

    if (info->load_failed) return;

    /* detach if the extension implements EphyExtensionIface */
    if (EPHY_IS_EXTENSION (info->extension))
    {
        g_list_foreach (manager->priv->windows, (GFunc) detach_window,
                info->extension);

        manager->priv->extensions =
            g_list_remove (manager->priv->extensions, info->extension);

        /* we own two refs to the extension, the one we added when
         * we added it to the priv->extensions list, and the one returned
         * from get_object. Release object, and queue a unref, since if the
         * extension has its own functions queued in the idle loop, the
         * functions must exist in memory before being called.
         */
        ephy_object_idle_unref (info->extension);
    }

    ephy_loader_release_object (info->loader, G_OBJECT (info->extension));

    info->info.active = FALSE;
    info->extension = NULL;
}

static void
sync_loaded_extensions (EphyExtensionsManager *manager)
{
    GConfClient *client;
    GConfValue *value;
    GSList *active_extensions = NULL;
    GList *l;
    gboolean active;
    ExtensionInfo *info;

    LOG ("Synching changed list of active extensions");

    client = gconf_client_get_default ();
    g_return_if_fail (client != NULL);

    value = gconf_client_get (client, CONF_LOADED_EXTENSIONS, NULL);

    /* make sure the extensions-manager-ui is loaded */
    if (value == NULL ||
        value->type != GCONF_VALUE_LIST ||
        gconf_value_get_list_type (value) != GCONF_VALUE_STRING)
    {
        active_extensions = g_slist_prepend (active_extensions,
                             g_strdup ("extensions-manager-ui"));
        eel_gconf_set_string_list (CONF_LOADED_EXTENSIONS, active_extensions);
    }
    else
    {
        active_extensions = eel_gconf_get_string_list (CONF_LOADED_EXTENSIONS);
    }

    for (l = manager->priv->data; l != NULL; l = l->next)
    {
        gboolean changed;
        
        info = (ExtensionInfo *) l->data;

        active = (g_slist_find_custom (active_extensions,
                           info->info.identifier,
                           (GCompareFunc) strcmp) != NULL);

        LOG ("Extension '%s' is %sactive and %sloaded",
             info->info.identifier,
             active ? "" : "not ",
             info->info.active ? "" : "not ");

        changed = ( info->info.enabled != active );

        info->info.enabled = active;

        if (active != info->info.active)
        {
            if (active)
            {
                load_extension (manager, info);
            }
            else
            {
                unload_extension (manager, info);
            }

            if (active == info->info.active)
            {
                changed = TRUE;
            }
        }
        
        if (changed)
        {
            g_signal_emit (manager, signals[CHANGED], 0, info);
        }
    }

    g_slist_foreach (active_extensions, (GFunc) g_free, NULL);
    g_slist_free (active_extensions);

    if (value != NULL)
    {
        gconf_value_free (value);
    }
    g_object_unref (client);
}

static void
ephy_extensions_manager_unload_file (EphyExtensionsManager *manager,
                     const char *path)
{
    GList *l;
    ExtensionInfo *info;
    char *identifier;

    identifier = path_to_identifier (path);

    l = g_list_find_custom (manager->priv->data, identifier,
                (GCompareFunc) find_extension_info);

    if (l != NULL)
    {
        info = (ExtensionInfo *) l->data;

        manager->priv->data = g_list_remove (manager->priv->data, info);

        if (info->info.active == TRUE)
        {
            unload_extension (manager, info);
        }

        g_signal_emit (manager, signals[REMOVED], 0, info);

        free_extension_info (info);
    }

    g_free (identifier);
}

static gboolean
reload_sync_cb (EphyExtensionsManager *manager)
{
    EphyExtensionsManagerPrivate *priv = manager->priv;

    if (priv->sync_timeout_id != 0)
    {
        g_source_remove (priv->sync_timeout_id);
        priv->sync_timeout_id = 0;
    }

    sync_loaded_extensions (manager);

    return FALSE;
}

static gboolean
reload_cb (gpointer *data)
{
    EphyExtensionsManager *manager = EPHY_EXTENSIONS_MANAGER (data[0]);
    EphyExtensionsManagerPrivate *priv = manager->priv;
    char *path = data[1];

    LOG ("Reloading %s", path);

    /* We still need path and don't want to remove the timeout
     * which will be removed automatically when we return, so 
     * just use _steal instead of _remove.
     */
    g_hash_table_steal (priv->reload_hash, path);

    ephy_extensions_manager_load_file (manager, path);
    g_free (path);

    /* Schedule a sync of active extensions */
    /* FIXME: just look if we need to activate *this* extension? */

    if (priv->sync_timeout_id != 0)
    {
        g_source_remove (priv->sync_timeout_id);
    }

    priv->sync_timeout_id = g_timeout_add_seconds (RELOAD_SYNC_DELAY,
                           (GSourceFunc) reload_sync_cb,
                           manager);
    return FALSE;
}

static void
schedule_load_from_monitor (EphyExtensionsManager *manager,
                const char *path)
{
    EphyExtensionsManagerPrivate *priv = manager->priv;
    char *identifier, *copy;
    gpointer *data;
    guint timeout_id;

    /* When a file is installed, it sometimes gets CREATED empty and then
     * gets its contents filled later (for a CHANGED signal). Theoretically
     * I suppose we could get a CHANGED signal when the file is half-full,
     * but I doubt that'll happen much (the files are <1000 bytes). We
     * don't want warnings all over the place, so we just wait a bit before
     * actually reloading the file. (We're assuming that if a file is
     * empty it'll be filled soon and this function will be called again.)
     *
     * Oh, and we return if the extension is already loaded, too.
     */

    identifier = path_to_identifier (path);
    g_return_if_fail (identifier != NULL);
    if (identifier == NULL) return;

    if (g_list_find_custom (manager->priv->data, identifier,
                (GCompareFunc) find_extension_info) != NULL)
    {
        g_free (identifier);
        return;
    }
    g_free (identifier);

    g_return_if_fail (priv->reload_hash != NULL);

    data = g_new (gpointer, 2);
    data[0] = (gpointer) manager;
    data[1] = copy = g_strdup (path);
    timeout_id = g_timeout_add_full (G_PRIORITY_LOW, RELOAD_DELAY,
                     (GSourceFunc) reload_cb,
                     data, (GDestroyNotify) g_free);
    g_hash_table_replace (priv->reload_hash, copy /* owns it */,
                  GUINT_TO_POINTER (timeout_id));
}

static void
dir_changed_cb (GFileMonitor *monitor,
        GFile *child,
        GFile *other_child,
        GFileMonitorEvent event_type,
        EphyExtensionsManager *manager)
{
    char *path;
    
    path = g_file_get_path (child);

    /*
     * We only deal with XML and INI files:
     * Add them to the manager when created, remove them when deleted.
     */
    if (format_from_path (path) == FORMAT_UNKNOWN) return;

    switch (event_type)
    {
        case G_FILE_MONITOR_EVENT_CREATED:
        case G_FILE_MONITOR_EVENT_CHANGED:
            schedule_load_from_monitor (manager, path);
            break;
        case G_FILE_MONITOR_EVENT_DELETED:
            ephy_extensions_manager_unload_file (manager, path);
            break;
        default:
            break;
    }
    
    g_free (path);
}

static void
ephy_extensions_manager_load_dir (EphyExtensionsManager *manager,
                  const char *path)
{
    DIR *d;
    struct dirent *e;
    char *file_path;
    GFile *directory;
    GFileMonitor *monitor;

    LOG ("Scanning directory '%s'", path);

    START_PROFILER ("Scanning directory")

    d = opendir (path);
    if (d == NULL)
    {
        return;
    }
    while ((e = readdir (d)) != NULL)
    {
        if (format_from_path (e->d_name) != FORMAT_UNKNOWN)
        {
            file_path = g_build_filename (path, e->d_name, NULL);
            ephy_extensions_manager_load_file (manager, file_path);
            g_free (file_path);
        }
    }
    closedir (d);

    directory = g_file_new_for_path (path);
    monitor = g_file_monitor_directory (directory, 0, NULL, NULL);

    if (monitor != NULL)
    {
        g_signal_connect (monitor, "changed",
                  G_CALLBACK (dir_changed_cb),
                  manager);
        manager->priv->dir_monitors = g_list_prepend
            (manager->priv->dir_monitors, monitor);
    }

    STOP_PROFILER ("Scanning directory")
}

static void
active_extensions_notifier (GConfClient *client,
                guint cnxn_id,
                GConfEntry *entry,
                EphyExtensionsManager *manager)
{
    sync_loaded_extensions (manager);
}

static void
cancel_timeout (gpointer data)
{
    guint id = GPOINTER_TO_UINT (data);

    g_source_remove (id);
}

static void
ephy_extensions_manager_init (EphyExtensionsManager *manager)
{
    EphyExtensionsManagerPrivate *priv;

    priv = manager->priv = EPHY_EXTENSIONS_MANAGER_GET_PRIVATE (manager);

    priv->reload_hash = g_hash_table_new_full (g_str_hash, g_str_equal,
                           (GDestroyNotify) g_free,
                           (GDestroyNotify) cancel_timeout);
}

void
ephy_extensions_manager_startup (EphyExtensionsManager *manager)
{
    char *path;

    g_return_if_fail (EPHY_IS_EXTENSIONS_MANAGER (manager));

    LOG ("EphyExtensionsManager startup");

    /* load the extensions descriptions */
    path = g_build_filename (ephy_dot_dir (), "extensions", NULL);
    ephy_extensions_manager_load_dir (manager, path);
    g_free (path);

    ephy_extensions_manager_load_dir (manager, EXTENSIONS_DIR);

    active_extensions_notifier (NULL, 0, NULL, manager);
    manager->priv->active_extensions_notifier_id =
        eel_gconf_notification_add
            (CONF_LOADED_EXTENSIONS,
             (GConfClientNotifyFunc) active_extensions_notifier,
             manager);
}

static void
ephy_extensions_manager_dispose (GObject *object)
{
    EphyExtensionsManager *manager = EPHY_EXTENSIONS_MANAGER (object);
    EphyExtensionsManagerPrivate *priv = manager->priv;

#ifdef ENABLE_LEGACY_FORMAT
    if (priv->xml2ini_xsl != NULL)
    {
        xsltFreeStylesheet (priv->xml2ini_xsl);
        priv->xml2ini_xsl = NULL;
    }
#endif

    if (priv->active_extensions_notifier_id != 0)
    {
        eel_gconf_notification_remove (priv->active_extensions_notifier_id);
        priv->active_extensions_notifier_id = 0;
    }

    if (priv->reload_hash != NULL)
    {
        g_hash_table_destroy (priv->reload_hash);
        priv->reload_hash = NULL;
    }

    if (priv->sync_timeout_id != 0)
    {
        g_source_remove (priv->sync_timeout_id);
        priv->sync_timeout_id = 0;
    }

    if (priv->dir_monitors != NULL)
    {
        g_list_foreach (priv->dir_monitors, (GFunc) g_file_monitor_cancel, NULL);
        g_list_free (priv->dir_monitors);
        priv->dir_monitors = NULL;
    }

    if (priv->extensions != NULL)
    {
        g_list_foreach (priv->extensions, (GFunc) g_object_unref, NULL);
        g_list_free (priv->extensions);
        priv->extensions = NULL;
    }

    if (priv->factories != NULL)
    {
        /* FIXME release loaded loaders */
        g_list_foreach (priv->factories, (GFunc) free_loader_info, NULL);
        g_list_free (priv->factories);
        priv->factories = NULL;
    }

    if (priv->data != NULL)
    {
        g_list_foreach (priv->data, (GFunc) free_extension_info, NULL);
        g_list_free (priv->data);
        priv->data = NULL;
    }

    if (priv->windows != NULL)
    {
        g_list_free (priv->windows);
        priv->windows = NULL;
    }

    G_OBJECT_CLASS (ephy_extensions_manager_parent_class)->dispose (object);
}

static void
attach_extension_to_window (EphyExtension *extension,
                EphyWindow *window)
{
    attach_window (window, extension);
}

static void
impl_attach_window (EphyExtension *extension,
            EphyWindow *window)
{
    EphyExtensionsManager *manager = EPHY_EXTENSIONS_MANAGER (extension);

    LOG ("Attach window %p", window);

    g_list_foreach (manager->priv->extensions,
            (GFunc) attach_extension_to_window, window);

    manager->priv->windows = g_list_prepend (manager->priv->windows, window);
}

static void
impl_detach_window (EphyExtension *extension,
            EphyWindow *window)
{
    EphyExtensionsManager *manager = EPHY_EXTENSIONS_MANAGER (extension);
    GList *tabs, *l;

    LOG ("Detach window %p", window);

    manager->priv->windows = g_list_remove (manager->priv->windows, window);

    g_object_ref (window);

    /* Detach tabs (uses impl_detach_tab) */
    tabs = ephy_embed_container_get_children (EPHY_EMBED_CONTAINER (window));
    for (l = tabs; l; l = l->next)
    {
        ephy_extension_detach_tab (extension, window,
                       EPHY_EMBED (l->data));
    }
    g_list_free (tabs);

    /* Then detach the window */
    g_list_foreach (manager->priv->extensions,
            (GFunc) ephy_extension_detach_window, window);

    g_object_unref (window);
}

static void
impl_attach_tab (EphyExtension *extension,
         EphyWindow *window,
         EphyEmbed *embed)
{
    EphyExtensionsManager *manager = EPHY_EXTENSIONS_MANAGER (extension);
    GList *l;

    LOG ("Attach window %p embed %p", window, embed);

    for (l = manager->priv->extensions; l; l = l->next)
    {
        ephy_extension_attach_tab (EPHY_EXTENSION (l->data),
                       window, embed);
    }
}

static void
impl_detach_tab (EphyExtension *extension,
         EphyWindow *window,
         EphyEmbed *embed)
{
    EphyExtensionsManager *manager = EPHY_EXTENSIONS_MANAGER (extension);
    GList *l;

    LOG ("Detach window %p embed %p", window, embed);

    g_object_ref (window);
    g_object_ref (embed);

    for (l = manager->priv->extensions; l; l = l->next)
    {
        ephy_extension_detach_tab (EPHY_EXTENSION (l->data),
                       window, embed);
    }

    g_object_unref (embed);
    g_object_unref (window);
}

static void
ephy_extensions_manager_iface_init (EphyExtensionIface *iface)
{
    iface->attach_window = impl_attach_window;
    iface->detach_window = impl_detach_window;
    iface->attach_tab    = impl_attach_tab;
    iface->detach_tab    = impl_detach_tab;
}

static void
ephy_extensions_manager_class_init (EphyExtensionsManagerClass *class)
{
    GObjectClass *object_class = G_OBJECT_CLASS (class);

    object_class->dispose = ephy_extensions_manager_dispose;

    signals[CHANGED] =
        g_signal_new ("changed",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_FIRST,
                  G_STRUCT_OFFSET (EphyExtensionsManagerClass, changed),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__POINTER,
                  G_TYPE_NONE,
                  1,
                  G_TYPE_POINTER);
    signals[ADDED] =
        g_signal_new ("added",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_FIRST,
                  G_STRUCT_OFFSET (EphyExtensionsManagerClass, added),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__POINTER,
                  G_TYPE_NONE,
                  1,
                  G_TYPE_POINTER);
    signals[REMOVED] =
        g_signal_new ("removed",
                  G_OBJECT_CLASS_TYPE (object_class),
                  G_SIGNAL_RUN_FIRST,
                  G_STRUCT_OFFSET (EphyExtensionsManagerClass, removed),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__POINTER,
                  G_TYPE_NONE,
                  1,
                  G_TYPE_POINTER);
    
    g_type_class_add_private (object_class, sizeof (EphyExtensionsManagerPrivate));
}