path: root/extensions/ds-registry.vala

/* ds-registry.vala
 *
 * Copyright © 2011 Michal Hruby <michal.mhr@gmail.com>
 * Copyright © 2011 Collabora Ltd.
 *             By Siegfried-Angel Gevatter Pujals <siegfried@gevatter.com>
 *
 * Based upon a Python implementation (2009-2010) by:
 *  Siegfried-Angel Gevatter Pujals <siegfried@gevatter.com>
 *  Mikkel Kamstrup Erlandsen <mikkel.kamstrup@gmail.com>
 *
 * 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 2.1 of the License, 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 Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

namespace Zeitgeist
{
    [DBus (name = "org.gnome.zeitgeist.DataSourceRegistry")]
    public interface RemoteRegistry: Object
    {
        [DBus (signature = "a(sssa(asaasay)bxb)")]
        public abstract Variant get_data_sources () throws Error;
        public abstract bool register_data_source (string unique_id,
            string name, string description,
            [DBus (signature = "a(asaasay)")] Variant event_templates, BusName? sender)
            throws Error;
        public abstract void set_data_source_enabled (string unique_id,
            bool enabled) throws Error;
        [DBus (signature = "(sssa(asaasay)bxb)")]
        public abstract Variant get_data_source_from_id (string id) throws Error;

        public signal void data_source_disconnected (
            [DBus (signature = "(sssa(asaasay)bxb)")] Variant data_source);
        public signal void data_source_enabled (string unique_id,
            bool enabled);
        public signal void data_source_registered (
            [DBus (signature = "(sssa(asaasay)bxb)")] Variant data_source);
    }

    class DataSource: Object
    {
        public string unique_id { get; set; }
        public string name { get; set; }
        public string description { get; set; }

        public GenericArray<Event>? event_templates { get; set; }

        public bool enabled { get; set; }
        public bool running { get; set; }
        public int64 timestamp { get; set; }

        public DataSource ()
        {
            Object ();
        }

        public DataSource.full (string unique_id, string name,
            string description, GenericArray<Event> templates)
        {
            Object (unique_id: unique_id, name: name, description: description,
                event_templates: templates);
        }

        public DataSource.from_variant (Variant variant,
            bool reset_running=false) throws EngineError
        {
            warn_if_fail (
                variant.get_type_string () == "(sssa("+Utils.SIG_EVENT+")bxb)"
                || variant.get_type_string () == "sssa("+Utils.SIG_EVENT+")");
            var iter = variant.iterator ();

            assert (iter.n_children () >= 4);
            unique_id = iter.next_value ().get_string ();
            name = iter.next_value ().get_string ();
            description = iter.next_value ().get_string ();
            event_templates = Events.from_variant (iter.next_value ());

            if (iter.n_children () > 4)
            {
                running = iter.next_value ().get_boolean ();
                if (reset_running)
                    running = false;
                timestamp = iter.next_value ().get_int64 ();
                enabled = iter.next_value ().get_boolean ();
            }
        }

        public Variant to_variant ()
        {
            var vb = new VariantBuilder (new VariantType (
                "(sssa("+Utils.SIG_EVENT+")bxb)"));

            vb.add ("s", unique_id);
            vb.add ("s", name);
            vb.add ("s", description);
            if (event_templates != null && event_templates.length > 0)
            {
                vb.add_value (Events.to_variant (event_templates));
            }
            else
            {
                vb.open (new VariantType ("a("+Utils.SIG_EVENT+")"));
                vb.close ();
            }

            vb.add ("b", running);
            vb.add ("x", timestamp);
            vb.add ("b", enabled);

            return vb.end ();
        }
    }

    namespace DataSources
    {
        private const string SIG_DATASOURCES =
            "a(sssa("+Utils.SIG_EVENT+")bxb)";

        private static HashTable<string, DataSource> from_variant (
            Variant sources_variant, bool reset_running=false) throws EngineError
        {
            var registry = new HashTable<string, DataSource> (
                str_hash, str_equal);

            warn_if_fail (
                sources_variant.get_type_string() == SIG_DATASOURCES);
            foreach (Variant ds_variant in sources_variant)
            {
                DataSource ds = new DataSource.from_variant (ds_variant,
                    reset_running);
                registry.insert (ds.unique_id, ds);
            }

            return registry;
        }

        private static Variant to_variant (
            HashTable<string, DataSource> sources)
        {
            var vb = new VariantBuilder (new VariantType (SIG_DATASOURCES));

            List<unowned DataSource> data_sources = sources.get_values ();
            data_sources.sort ((a, b) =>
            {
                return strcmp (a.unique_id, b.unique_id);
            });

            foreach (unowned DataSource ds in data_sources)
            {
                vb.add_value (ds.to_variant ());
            }

            return vb.end ();
        }
    }

    class DataSourceRegistry: Extension, RemoteRegistry
    {
        private HashTable<string, DataSource> sources;
        private HashTable<string, GenericArray<BusName>> running;
        private uint registration_id;
        private bool dirty;

        private static const uint DISK_WRITE_TIMEOUT = 5 * 60; // 5 minutes

        DataSourceRegistry ()
        {
            Object ();
        }

        construct
        {
            running = new HashTable<string, GenericArray<BusName?>>(
                str_hash, str_equal);

            Variant? registry = retrieve_config ("registry",
                DataSources.SIG_DATASOURCES);
            if (registry != null) {
                try {
                    sources = DataSources.from_variant (registry, true);
                } catch (EngineError e) {
                    warning ("Error while loading datasource registry: %s", e.message);
                }
            } else {
                sources = new HashTable<string, DataSource> (
                    str_hash, str_equal);
            }

            // this will be called after bus is acquired, so it shouldn't block
            try
            {
                var connection = Bus.get_sync (BusType.SESSION, null);
                registration_id = connection.register_object<RemoteRegistry> (
                    "/org/gnome/zeitgeist/data_source_registry", this);

                connection.signal_subscribe ("org.freedesktop.DBus",
                    "org.freedesktop.DBus", "NameOwnerChanged",
                    "/org/freedesktop/DBus", null, 0,
                    name_owner_changed);
            }
            catch (Error err)
            {
                warning ("%s", err.message);
            }

            // Changes are saved to the DB every few seconds and at unload.
            Timeout.add_seconds (DISK_WRITE_TIMEOUT, flush, Priority.LOW);
        }

        public override void unload ()
        {
            try
            {
                var connection = Bus.get_sync (BusType.SESSION, null);
                if (registration_id != 0)
                {
                    connection.unregister_object (registration_id);
                    registration_id = 0;
                }
            }
            catch (Error err)
            {
                warning ("%s", err.message);
            }

            flush ();
            debug ("%s, this.ref_count = %u", Log.METHOD, this.ref_count);
        }

        public Variant get_data_sources ()
        {
            return DataSources.to_variant (sources);
        }

        private bool is_sender_known (BusName sender,
            GenericArray<BusName> sender_array)
        {
            for (int i = 0; i < sender_array.length; i++)
            {
                if (sender == sender_array[i])
                    return true;
            }
            return false;
        }

        public bool register_data_source (string unique_id, string name,
            string description, Variant event_templates, BusName? sender) throws EngineError
        {
            debug ("%s: %s, %s, %s", Log.METHOD, unique_id, name, description);
            if (sender == null)
            {
                warning ("%s: sender == null, ignoring request", Log.METHOD);
                return false;
            }


            var sender_array = running.lookup (unique_id);
            if (sender_array == null)
            {
                running.insert (unique_id, new GenericArray<BusName?>());
                running.lookup (unique_id).add (sender);
            }
            else if (is_sender_known (sender, sender_array))
            {
                running.lookup (unique_id).add (sender);
            }

            unowned DataSource? ds = sources.lookup (unique_id);
            if (ds != null)
            {
                var templates = Events.from_variant (event_templates);
                ds.name = name;
                ds.description = description;
                ds.event_templates = templates;
                ds.timestamp = Timestamp.now ();
                ds.running = true;
                dirty = true;

                data_source_registered (ds.to_variant ());

                return ds.enabled;
            }
            else
            {
                var templates = Events.from_variant (event_templates);
                DataSource new_ds = new DataSource.full (unique_id, name,
                    description, templates);
                new_ds.enabled = true;
                new_ds.running = true;
                new_ds.timestamp = Timestamp.now ();
                sources.insert (unique_id, new_ds);
                dirty = true;

                data_source_registered (new_ds.to_variant ());

                return new_ds.enabled;
            }

        }

        public void set_data_source_enabled (string unique_id, bool enabled)
        {
            debug ("%s: %s, %d", Log.METHOD, unique_id, (int) enabled);
            unowned DataSource? ds = sources.lookup (unique_id);
            if (ds != null)
            {
                if (ds.enabled != enabled)
                {
                    ds.enabled = enabled;
                    dirty = true;
                    data_source_enabled (unique_id, enabled);
                }
            }
            else
            {
                warning ("DataSource \"%s\" isn't registered!", unique_id);
            }
        }

        public Variant get_data_source_from_id (string unique_id) throws Error
        {
            unowned DataSource? ds = sources.lookup (unique_id);
            if (ds != null)
            {
                return ds.to_variant ();
            }

            throw new EngineError.INVALID_KEY (
                "Datasource with unique ID: %s not found".printf (unique_id));
        }

        public override void pre_insert_events (GenericArray<Event?> events,
            BusName? sender)
        {
            foreach (string unique_id in running.get_keys())
            {
                GenericArray<BusName?> bus_names = running.lookup (unique_id);
                if (is_sender_known (sender, bus_names))
                {
                    var data_source = sources.lookup (unique_id);

                    data_source.timestamp =  Timestamp.now ();
                    dirty = true;

                    if (!data_source.enabled)
                    {
                        for (int i = 0; i < events.length; i++)
                            events[i] = null;
                    }
                }
            }
        }

        /*
         * Cleanup disconnected clients and mark data-sources as not running
         * when no client remains.
         **/
        private void name_owner_changed (DBusConnection conn, string sender,
            string path, string interface_name, string signal_name,
            Variant parameters)
        {
            var name = parameters.get_child_value (0).dup_string ();
            //var old_owner = parameters.get_child_value (1).dup_string ();
            var new_owner = parameters.get_child_value (2).dup_string ();
            if (new_owner != "") return;

            // Are there data-sources with this bus name?
            var disconnected_ds = new GenericArray<DataSource> ();
            {
                var iter = HashTableIter<string, GenericArray<BusName?>> (
                    running);
                unowned string uid;
                unowned GenericArray<BusName> name_arr;
                while (iter.next (out uid, out name_arr))
                {
                    for (int i = 0; i < name_arr.length; i++)
                    {
                        if (name_arr[i] == name)
                        {
                            disconnected_ds.add (sources.lookup (uid));
                            name_arr.remove_index_fast (i--);
                        }
                    }
                }
            }

            if (disconnected_ds.length == 0) return;

            for (int i = 0; i < disconnected_ds.length; i++)
            {
                var ds = disconnected_ds[i];
                unowned string uid = ds.unique_id;
                debug ("Client disconnected: %s [%s]", ds.name, uid);

                // FIXME: Update here or change semantics to "last insert"?
                ds.timestamp = Timestamp.now ();
                dirty = true;

                if (running.lookup (uid).length == 0)
                {
                    debug ("No remaining client running: %s [%s]",
                        ds.name, uid);
                    running.remove (uid);
                    ds.running = false;

                    data_source_disconnected (ds.to_variant ());
                }
            }
        }

        private bool flush ()
        {
            if (dirty)
            {
                Variant v = DataSources.to_variant (sources);
                store_config ("registry", v);
                dirty = false;
            }
            return true;
        }
    }

    [ModuleInit]
#if BUILTIN_EXTENSIONS
    public static Type data_source_registry_init (TypeModule module)
    {
#else
    public static Type extension_register (TypeModule module)
    {
#endif
        return typeof (DataSourceRegistry);
    }
}

// vim:expandtab:ts=4:sw=4