/*
 * Copyright (C) 2007 Novell, Inc.
 *
 * Inspired by various other pieces of code including GsmClient (C)
 * 2001 Havoc Pennington, MateClient (C) 1998 Carsten Schaar, and twm
 * session code (C) 1998 The Open Group.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"

#include "eggsmclient.h"
#include "eggsmclient-private.h"

#include "eggdesktopfile.h"

#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <X11/SM/SMlib.h>

#include <gtk/gtk.h>
#include <gdk/gdk.h>
#if GTK_CHECK_VERSION (3, 0, 0)
#include <gdk/gdkx.h>
#endif

#define EGG_TYPE_SM_CLIENT_XSMP            (egg_sm_client_xsmp_get_type ())
#define EGG_SM_CLIENT_XSMP(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), EGG_TYPE_SM_CLIENT_XSMP, EggSMClientXSMP))
#define EGG_SM_CLIENT_XSMP_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), EGG_TYPE_SM_CLIENT_XSMP, EggSMClientXSMPClass))
#define EGG_IS_SM_CLIENT_XSMP(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), EGG_TYPE_SM_CLIENT_XSMP))
#define EGG_IS_SM_CLIENT_XSMP_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), EGG_TYPE_SM_CLIENT_XSMP))
#define EGG_SM_CLIENT_XSMP_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), EGG_TYPE_SM_CLIENT_XSMP, EggSMClientXSMPClass))

typedef struct _EggSMClientXSMP        EggSMClientXSMP;
typedef struct _EggSMClientXSMPClass   EggSMClientXSMPClass;

/* These mostly correspond to the similarly-named states in section
 * 9.1 of the XSMP spec. Some of the states there aren't represented
 * here, because we don't need them. SHUTDOWN_CANCELLED is slightly
 * different from the spec; we use it when the client is IDLE after a
 * ShutdownCancelled message, but the application is still interacting
 * and doesn't know the shutdown has been cancelled yet.
 */
typedef enum
{
    XSMP_STATE_IDLE,
    XSMP_STATE_SAVE_YOURSELF,
    XSMP_STATE_INTERACT_REQUEST,
    XSMP_STATE_INTERACT,
    XSMP_STATE_SAVE_YOURSELF_DONE,
    XSMP_STATE_SHUTDOWN_CANCELLED,
    XSMP_STATE_CONNECTION_CLOSED
} EggSMClientXSMPState;

static const char *state_names[] =
{
    "idle",
    "save-yourself",
    "interact-request",
    "interact",
    "save-yourself-done",
    "shutdown-cancelled",
    "connection-closed"
};

#define EGG_SM_CLIENT_XSMP_STATE(xsmp) (state_names[(xsmp)->state])

struct _EggSMClientXSMP
{
    EggSMClient parent;

    SmcConn connection;
    char *client_id;

    EggSMClientXSMPState state;
    char **restart_command;
    gboolean set_restart_command;
    int restart_style;

    guint idle;

    /* Current SaveYourself state */
    guint expecting_initial_save_yourself : 1;
    guint need_save_state : 1;
    guint need_quit_requested : 1;
    guint interact_errors : 1;
    guint shutting_down : 1;

    /* Todo list */
    guint waiting_to_set_initial_properties : 1;
    guint waiting_to_emit_quit : 1;
    guint waiting_to_emit_quit_cancelled : 1;
    guint waiting_to_save_myself : 1;

};

struct _EggSMClientXSMPClass
{
    EggSMClientClass parent_class;

};

static void     sm_client_xsmp_startup (EggSMClient *client,
                                        const char  *client_id);
static void     sm_client_xsmp_set_restart_command (EggSMClient  *client,
        int           argc,
        const char  **argv);
static void     sm_client_xsmp_will_quit (EggSMClient *client,
        gboolean     will_quit);
static gboolean sm_client_xsmp_end_session (EggSMClient         *client,
        EggSMClientEndStyle  style,
        gboolean  request_confirmation);

static void xsmp_save_yourself      (SmcConn   smc_conn,
                                     SmPointer client_data,
                                     int       save_style,
                                     Bool      shutdown,
                                     int       interact_style,
                                     Bool      fast);
static void xsmp_die                (SmcConn   smc_conn,
                                     SmPointer client_data);
static void xsmp_save_complete      (SmcConn   smc_conn,
                                     SmPointer client_data);
static void xsmp_shutdown_cancelled (SmcConn   smc_conn,
                                     SmPointer client_data);
static void xsmp_interact           (SmcConn   smc_conn,
                                     SmPointer client_data);

static SmProp *array_prop        (const char    *name,
                                  ...);
static SmProp *ptrarray_prop     (const char    *name,
                                  GPtrArray     *values);
static SmProp *string_prop       (const char    *name,
                                  const char    *value);
static SmProp *card8_prop        (const char    *name,
                                  unsigned char  value);

static void set_properties         (EggSMClientXSMP *xsmp, ...);
static void delete_properties      (EggSMClientXSMP *xsmp, ...);

static GPtrArray *generate_command (char       **restart_command,
                                    const char  *client_id,
                                    const char  *state_file);

static void save_state            (EggSMClientXSMP *xsmp);
static void do_save_yourself      (EggSMClientXSMP *xsmp);
static void update_pending_events (EggSMClientXSMP *xsmp);

static void     ice_init             (void);
static gboolean process_ice_messages (IceConn       ice_conn);
static void     smc_error_handler    (SmcConn       smc_conn,
                                      Bool          swap,
                                      int           offending_minor_opcode,
                                      unsigned long offending_sequence,
                                      int           error_class,
                                      int           severity,
                                      SmPointer     values);

G_DEFINE_TYPE (EggSMClientXSMP, egg_sm_client_xsmp, EGG_TYPE_SM_CLIENT)

static void
egg_sm_client_xsmp_init (EggSMClientXSMP *xsmp)
{
    xsmp->state = XSMP_STATE_CONNECTION_CLOSED;
    xsmp->connection = NULL;
    xsmp->restart_style = SmRestartIfRunning;
}

static void
egg_sm_client_xsmp_class_init (EggSMClientXSMPClass *klass)
{
    EggSMClientClass *sm_client_class = EGG_SM_CLIENT_CLASS (klass);

    sm_client_class->startup             = sm_client_xsmp_startup;
    sm_client_class->set_restart_command = sm_client_xsmp_set_restart_command;
    sm_client_class->will_quit           = sm_client_xsmp_will_quit;
    sm_client_class->end_session         = sm_client_xsmp_end_session;
}

EggSMClient *
egg_sm_client_xsmp_new (void)
{
    if (!g_getenv ("SESSION_MANAGER"))
        return NULL;

    return g_object_new (EGG_TYPE_SM_CLIENT_XSMP, NULL);
}

static gboolean
sm_client_xsmp_set_initial_properties (gpointer user_data)
{
    EggSMClientXSMP *xsmp = user_data;
    EggDesktopFile *desktop_file;
    GPtrArray *clone, *restart;
    char pid_str[64];

    if (xsmp->idle)
    {
        g_source_remove (xsmp->idle);
        xsmp->idle = 0;
    }
    xsmp->waiting_to_set_initial_properties = FALSE;

    if (egg_sm_client_get_mode () == EGG_SM_CLIENT_MODE_NO_RESTART)
        xsmp->restart_style = SmRestartNever;

    /* Parse info out of desktop file */
    desktop_file = egg_get_desktop_file ();
    if (desktop_file)
    {
        GError *err = NULL;
        char *cmdline, **argv;
        int argc;

        if (xsmp->restart_style == SmRestartIfRunning)
        {
            if (egg_desktop_file_get_boolean (desktop_file,
                                              "X-MATE-AutoRestart", NULL))
                xsmp->restart_style = SmRestartImmediately;
        }

        if (!xsmp->set_restart_command)
        {
            cmdline = egg_desktop_file_parse_exec (desktop_file, NULL, &err);
            if (cmdline && g_shell_parse_argv (cmdline, &argc, &argv, &err))
            {
                egg_sm_client_set_restart_command (EGG_SM_CLIENT (xsmp),
                                                   argc, (const char **)argv);
                g_strfreev (argv);
            }
            else
            {
                g_warning ("Could not parse Exec line in desktop file: %s",
                           err->message);
                g_error_free (err);
            }
            g_free (cmdline);
        }
    }

    if (!xsmp->set_restart_command)
        xsmp->restart_command = g_strsplit (g_get_prgname (), " ", -1);

    clone = generate_command (xsmp->restart_command, NULL, NULL);
    restart = generate_command (xsmp->restart_command, xsmp->client_id, NULL);

    g_debug ("Setting initial properties");

    /* Program, CloneCommand, RestartCommand, and UserID are required.
     * ProcessID isn't required, but the SM may be able to do something
     * useful with it.
     */
    g_snprintf (pid_str, sizeof (pid_str), "%lu", (gulong) getpid ());
    set_properties (xsmp,
                    string_prop   (SmProgram, g_get_prgname ()),
                    ptrarray_prop (SmCloneCommand, clone),
                    ptrarray_prop (SmRestartCommand, restart),
                    string_prop   (SmUserID, g_get_user_name ()),
                    string_prop   (SmProcessID, pid_str),
                    card8_prop    (SmRestartStyleHint, xsmp->restart_style),
                    NULL);
    g_ptr_array_free (clone, TRUE);
    g_ptr_array_free (restart, TRUE);

    if (desktop_file)
    {
        set_properties (xsmp,
                        string_prop ("_GSM_DesktopFile", egg_desktop_file_get_source (desktop_file)),
                        NULL);
    }

    update_pending_events (xsmp);
    return FALSE;
}

/* This gets called from two different places: xsmp_die() (when the
 * server asks us to disconnect) and process_ice_messages() (when the
 * server disconnects unexpectedly).
 */
static void
sm_client_xsmp_disconnect (EggSMClientXSMP *xsmp)
{
    SmcConn connection;

    if (!xsmp->connection)
        return;

    g_debug ("Disconnecting");

    connection = xsmp->connection;
    xsmp->connection = NULL;
    SmcCloseConnection (connection, 0, NULL);
    xsmp->state = XSMP_STATE_CONNECTION_CLOSED;

    xsmp->waiting_to_save_myself = FALSE;
    update_pending_events (xsmp);
}

static void
sm_client_xsmp_startup (EggSMClient *client,
                        const char  *client_id)
{
    EggSMClientXSMP *xsmp = (EggSMClientXSMP *)client;
    SmcCallbacks callbacks;
    char *ret_client_id;
    char error_string_ret[256];

    xsmp->client_id = g_strdup (client_id);

    ice_init ();
    SmcSetErrorHandler (smc_error_handler);

    callbacks.save_yourself.callback      = xsmp_save_yourself;
    callbacks.die.callback                = xsmp_die;
    callbacks.save_complete.callback      = xsmp_save_complete;
    callbacks.shutdown_cancelled.callback = xsmp_shutdown_cancelled;

    callbacks.save_yourself.client_data      = xsmp;
    callbacks.die.client_data                = xsmp;
    callbacks.save_complete.client_data      = xsmp;
    callbacks.shutdown_cancelled.client_data = xsmp;

    client_id = NULL;
    error_string_ret[0] = '\0';
    xsmp->connection =
        SmcOpenConnection (NULL, xsmp, SmProtoMajor, SmProtoMinor,
                           SmcSaveYourselfProcMask | SmcDieProcMask |
                           SmcSaveCompleteProcMask |
                           SmcShutdownCancelledProcMask,
                           &callbacks,
                           xsmp->client_id, &ret_client_id,
                           sizeof (error_string_ret), error_string_ret);

    if (!xsmp->connection)
    {
        g_warning ("Failed to connect to the session manager: %s\n",
                   error_string_ret[0] ?
                   error_string_ret : "no error message given");
        xsmp->state = XSMP_STATE_CONNECTION_CLOSED;
        return;
    }

    /* We expect a pointless initial SaveYourself if either (a) we
     * didn't have an initial client ID, or (b) we DID have an initial
     * client ID, but the server rejected it and gave us a new one.
     */
    if (!xsmp->client_id ||
            (ret_client_id && strcmp (xsmp->client_id, ret_client_id) != 0))
        xsmp->expecting_initial_save_yourself = TRUE;

    if (ret_client_id)
    {
        g_free (xsmp->client_id);
        xsmp->client_id = g_strdup (ret_client_id);
        free (ret_client_id);

#if GTK_CHECK_VERSION (3, 0, 0)
        gdk_x11_set_sm_client_id (xsmp->client_id);
#else
        gdk_threads_enter ();
        gdk_set_sm_client_id (xsmp->client_id);
        gdk_threads_leave ();
#endif

        g_debug ("Got client ID \"%s\"", xsmp->client_id);
    }

    xsmp->state = XSMP_STATE_IDLE;

    /* Do not set the initial properties until we reach the main loop,
     * so that the application has a chance to call
     * egg_set_desktop_file(). (This may also help the session manager
     * have a better idea of when the application is fully up and
     * running.)
     */
    xsmp->waiting_to_set_initial_properties = TRUE;
    xsmp->idle = g_idle_add (sm_client_xsmp_set_initial_properties, client);
}

static void
sm_client_xsmp_set_restart_command (EggSMClient  *client,
                                    int           argc,
                                    const char  **argv)
{
    EggSMClientXSMP *xsmp = (EggSMClientXSMP *)client;
    int i;

    g_strfreev (xsmp->restart_command);

    xsmp->restart_command = g_new (char *, argc + 1);
    for (i = 0; i < argc; i++)
        xsmp->restart_command[i] = g_strdup (argv[i]);
    xsmp->restart_command[i] = NULL;

    xsmp->set_restart_command = TRUE;
}

static void
sm_client_xsmp_will_quit (EggSMClient *client,
                          gboolean     will_quit)
{
    EggSMClientXSMP *xsmp = (EggSMClientXSMP *)client;

    if (xsmp->state == XSMP_STATE_CONNECTION_CLOSED)
    {
        /* The session manager has already exited! Schedule a quit
         * signal.
         */
        xsmp->waiting_to_emit_quit = TRUE;
        update_pending_events (xsmp);
        return;
    }
    else if (xsmp->state == XSMP_STATE_SHUTDOWN_CANCELLED)
    {
        /* We received a ShutdownCancelled message while the application
         * was interacting; Schedule a quit_cancelled signal.
         */
        xsmp->waiting_to_emit_quit_cancelled = TRUE;
        update_pending_events (xsmp);
        return;
    }

    g_return_if_fail (xsmp->state == XSMP_STATE_INTERACT);

    g_debug ("Sending InteractDone(%s)", will_quit ? "False" : "True");
    SmcInteractDone (xsmp->connection, !will_quit);

    if (will_quit && xsmp->need_save_state)
        save_state (xsmp);

    g_debug ("Sending SaveYourselfDone(%s)", will_quit ? "True" : "False");
    SmcSaveYourselfDone (xsmp->connection, will_quit);
    xsmp->state = XSMP_STATE_SAVE_YOURSELF_DONE;
}

static gboolean
sm_client_xsmp_end_session (EggSMClient         *client,
                            EggSMClientEndStyle  style,
                            gboolean             request_confirmation)
{
    EggSMClientXSMP *xsmp = (EggSMClientXSMP *)client;
    int save_type;

    /* To end the session via XSMP, we have to send a
     * SaveYourselfRequest. We aren't allowed to do that if anything
     * else is going on, but we don't want to expose this fact to the
     * application. So we do our best to patch things up here...
     *
     * In the worst case, this method might block for some length of
     * time in process_ice_messages, but the only time that code path is
     * honestly likely to get hit is if the application tries to end the
     * session as the very first thing it does, in which case it
     * probably won't actually block anyway. It's not worth gunking up
     * the API to try to deal nicely with the other 0.01% of cases where
     * this happens.
     */

    while (xsmp->state != XSMP_STATE_IDLE ||
            xsmp->expecting_initial_save_yourself)
    {
        /* If we're already shutting down, we don't need to do anything. */
        if (xsmp->shutting_down)
            return TRUE;

        switch (xsmp->state)
        {
        case XSMP_STATE_CONNECTION_CLOSED:
            return FALSE;

        case XSMP_STATE_SAVE_YOURSELF:
            /* Trying to log out from the save_state callback? Whatever.
             * Abort the save_state.
             */
            SmcSaveYourselfDone (xsmp->connection, FALSE);
            xsmp->state = XSMP_STATE_SAVE_YOURSELF_DONE;
            break;

        case XSMP_STATE_INTERACT_REQUEST:
        case XSMP_STATE_INTERACT:
        case XSMP_STATE_SHUTDOWN_CANCELLED:
            /* Already in a shutdown-related state, just ignore
             * the new shutdown request...
             */
            return TRUE;

        case XSMP_STATE_IDLE:
            if (xsmp->waiting_to_set_initial_properties)
                sm_client_xsmp_set_initial_properties (xsmp);

            if (!xsmp->expecting_initial_save_yourself)
                break;
            /* else fall through */

        case XSMP_STATE_SAVE_YOURSELF_DONE:
            /* We need to wait for some response from the server.*/
            process_ice_messages (SmcGetIceConnection (xsmp->connection));
            break;

        default:
            /* Hm... shouldn't happen */
            return FALSE;
        }
    }

    /* xfce4-session will do the wrong thing if we pass SmSaveGlobal and
     * the user chooses to save the session. But mate-session will do
     * the wrong thing if we pass SmSaveBoth and the user chooses NOT to
     * save the session... Sigh.
     */
    if (!strcmp (SmcVendor (xsmp->connection), "xfce4-session"))
        save_type = SmSaveBoth;
    else
        save_type = SmSaveGlobal;

    g_debug ("Sending SaveYourselfRequest(SmSaveGlobal, Shutdown, SmInteractStyleAny, %sFast)", request_confirmation ? "!" : "");
    SmcRequestSaveYourself (xsmp->connection,
                            save_type,
                            True, /* shutdown */
                            SmInteractStyleAny,
                            !request_confirmation, /* fast */
                            True /* global */);
    return TRUE;
}

static gboolean
idle_do_pending_events (gpointer data)
{
    EggSMClientXSMP *xsmp = data;
    EggSMClient *client = data;

#if !GTK_CHECK_VERSION (3, 0, 0)
    gdk_threads_enter ();
#endif

    xsmp->idle = 0;

    if (xsmp->waiting_to_emit_quit)
    {
        xsmp->waiting_to_emit_quit = FALSE;
        egg_sm_client_quit (client);
        goto out;
    }

    if (xsmp->waiting_to_emit_quit_cancelled)
    {
        xsmp->waiting_to_emit_quit_cancelled = FALSE;
        egg_sm_client_quit_cancelled (client);
        xsmp->state = XSMP_STATE_IDLE;
    }

    if (xsmp->waiting_to_save_myself)
    {
        xsmp->waiting_to_save_myself = FALSE;
        do_save_yourself (xsmp);
    }

out:
#if !GTK_CHECK_VERSION (3, 0, 0)
    gdk_threads_leave ();
#endif
    return FALSE;
}

static void
update_pending_events (EggSMClientXSMP *xsmp)
{
    gboolean want_idle =
        xsmp->waiting_to_emit_quit ||
        xsmp->waiting_to_emit_quit_cancelled ||
        xsmp->waiting_to_save_myself;

    if (want_idle)
    {
        if (xsmp->idle == 0)
            xsmp->idle = g_idle_add (idle_do_pending_events, xsmp);
    }
    else
    {
        if (xsmp->idle != 0)
            g_source_remove (xsmp->idle);
        xsmp->idle = 0;
    }
}

static void
fix_broken_state (EggSMClientXSMP *xsmp, const char *message,
                  gboolean send_interact_done,
                  gboolean send_save_yourself_done)
{
    g_warning ("Received XSMP %s message in state %s: client or server error",
               message, EGG_SM_CLIENT_XSMP_STATE (xsmp));

    /* Forget any pending SaveYourself plans we had */
    xsmp->waiting_to_save_myself = FALSE;
    update_pending_events (xsmp);

    if (send_interact_done)
        SmcInteractDone (xsmp->connection, False);
    if (send_save_yourself_done)
        SmcSaveYourselfDone (xsmp->connection, True);

    xsmp->state = send_save_yourself_done ? XSMP_STATE_SAVE_YOURSELF_DONE : XSMP_STATE_IDLE;
}

/* SM callbacks */

static void
xsmp_save_yourself (SmcConn   smc_conn,
                    SmPointer client_data,
                    int       save_type,
                    Bool      shutdown,
                    int       interact_style,
                    Bool      fast)
{
    EggSMClientXSMP *xsmp = client_data;
    gboolean wants_quit_requested;

    g_debug ("Received SaveYourself(%s, %s, %s, %s) in state %s",
             save_type == SmSaveLocal ? "SmSaveLocal" :
             save_type == SmSaveGlobal ? "SmSaveGlobal" : "SmSaveBoth",
             shutdown ? "Shutdown" : "!Shutdown",
             interact_style == SmInteractStyleAny ? "SmInteractStyleAny" :
             interact_style == SmInteractStyleErrors ? "SmInteractStyleErrors" :
             "SmInteractStyleNone", fast ? "Fast" : "!Fast",
             EGG_SM_CLIENT_XSMP_STATE (xsmp));

    if (xsmp->state != XSMP_STATE_IDLE &&
            xsmp->state != XSMP_STATE_SHUTDOWN_CANCELLED)
    {
        fix_broken_state (xsmp, "SaveYourself", FALSE, TRUE);
        return;
    }

    if (xsmp->waiting_to_set_initial_properties)
        sm_client_xsmp_set_initial_properties (xsmp);

    /* If this is the initial SaveYourself, ignore it; we've already set
     * properties and there's no reason to actually save state too.
     */
    if (xsmp->expecting_initial_save_yourself)
    {
        xsmp->expecting_initial_save_yourself = FALSE;

        if (save_type == SmSaveLocal &&
                interact_style == SmInteractStyleNone &&
                !shutdown && !fast)
        {
            g_debug ("Sending SaveYourselfDone(True) for initial SaveYourself");
            SmcSaveYourselfDone (xsmp->connection, True);
            /* As explained in the comment at the end of
             * do_save_yourself(), SAVE_YOURSELF_DONE is the correct
             * state here, not IDLE.
             */
            xsmp->state = XSMP_STATE_SAVE_YOURSELF_DONE;
            return;
        }
        else
            g_warning ("First SaveYourself was not the expected one!");
    }

    /* Even ignoring the "fast" flag completely, there are still 18
     * different combinations of save_type, shutdown and interact_style.
     * We interpret them as follows:
     *
     *   Type  Shutdown  Interact	 Interpretation
     *     G      F       A/E/N  	 do nothing (1)
     *     G      T         N    	 do nothing (1)*
     *     G      T        A/E   	 quit_requested (2)
     *    L/B     F       A/E/N  	 save_state (3)
     *    L/B     T         N    	 save_state (3)*
     *    L/B     T        A/E   	 quit_requested, then save_state (4)
     *
     *   1. Do nothing, because the SM asked us to do something
     *      uninteresting (save open files, but then don't quit
     *      afterward) or rude (save open files without asking the user
     *      for confirmation).
     *
     *   2. Request interaction and then emit ::quit_requested. This
     *      perhaps isn't quite correct for the SmInteractStyleErrors
     *      case, but we don't care.
     *
     *   3. Emit ::save_state. The SmSaveBoth SaveYourselfs in these
     *      rows essentially get demoted to SmSaveLocal, because their
     *      Global halves correspond to "do nothing".
     *
     *   4. Request interaction, emit ::quit_requested, and then emit
     *      ::save_state after interacting. This is the SmSaveBoth
     *      equivalent of #2, but we also promote SmSaveLocal shutdown
     *      SaveYourselfs to SmSaveBoth here, because we want to give
     *      the user a chance to save open files before quitting.
     *
     * (* It would be nice if we could do something useful when the
     * session manager sends a SaveYourself with shutdown True and
     * SmInteractStyleNone. But we can't, so we just pretend it didn't
     * even tell us it was shutting down. The docs for ::quit mention
     * that it might not always be preceded by ::quit_requested.)
     */

    /* As an optimization, we don't actually request interaction and
     * emit ::quit_requested if the application isn't listening to the
     * signal.
     */
    wants_quit_requested = g_signal_has_handler_pending (xsmp, g_signal_lookup ("quit_requested", EGG_TYPE_SM_CLIENT), 0, FALSE);

    xsmp->need_save_state     = (save_type != SmSaveGlobal);
    xsmp->need_quit_requested = (shutdown && wants_quit_requested &&
                                 interact_style != SmInteractStyleNone);
    xsmp->interact_errors     = (interact_style == SmInteractStyleErrors);

    xsmp->shutting_down       = shutdown;

    do_save_yourself (xsmp);
}

static void
do_save_yourself (EggSMClientXSMP *xsmp)
{
    if (xsmp->state == XSMP_STATE_SHUTDOWN_CANCELLED)
    {
        /* The SM cancelled a previous SaveYourself, but we haven't yet
         * had a chance to tell the application, so we can't start
         * processing this SaveYourself yet.
         */
        xsmp->waiting_to_save_myself = TRUE;
        update_pending_events (xsmp);
        return;
    }

    if (xsmp->need_quit_requested)
    {
        xsmp->state = XSMP_STATE_INTERACT_REQUEST;

        g_debug ("Sending InteractRequest(%s)",
                 xsmp->interact_errors ? "Error" : "Normal");
        SmcInteractRequest (xsmp->connection,
                            xsmp->interact_errors ? SmDialogError : SmDialogNormal,
                            xsmp_interact,
                            xsmp);
        return;
    }

    if (xsmp->need_save_state)
    {
        save_state (xsmp);

        /* Though unlikely, the client could have been disconnected
         * while the application was saving its state.
         */
        if (!xsmp->connection)
            return;
    }

    g_debug ("Sending SaveYourselfDone(True)");
    SmcSaveYourselfDone (xsmp->connection, True);

    /* The client state diagram in the XSMP spec says that after a
     * non-shutdown SaveYourself, we go directly back to "idle". But
     * everything else in both the XSMP spec and the libSM docs
     * disagrees.
     */
    xsmp->state = XSMP_STATE_SAVE_YOURSELF_DONE;
}

static void
save_state (EggSMClientXSMP *xsmp)
{
    GKeyFile *state_file;
    char *state_file_path, *data;
    EggDesktopFile *desktop_file;
    GPtrArray *restart;
    int offset, fd;

    /* We set xsmp->state before emitting save_state, but our caller is
     * responsible for setting it back afterward.
     */
    xsmp->state = XSMP_STATE_SAVE_YOURSELF;

    state_file = egg_sm_client_save_state ((EggSMClient *)xsmp);
    if (!state_file)
    {
        restart = generate_command (xsmp->restart_command, xsmp->client_id, NULL);
        set_properties (xsmp,
                        ptrarray_prop (SmRestartCommand, restart),
                        NULL);
        g_ptr_array_free (restart, TRUE);
        delete_properties (xsmp, SmDiscardCommand, NULL);
        return;
    }

    desktop_file = egg_get_desktop_file ();
    if (desktop_file)
    {
        GKeyFile *merged_file;
        char *desktop_file_path;

        merged_file = g_key_file_new ();
        desktop_file_path =
            g_filename_from_uri (egg_desktop_file_get_source (desktop_file),
                                 NULL, NULL);
        if (desktop_file_path &&
                g_key_file_load_from_file (merged_file, desktop_file_path,
                                           G_KEY_FILE_KEEP_COMMENTS |
                                           G_KEY_FILE_KEEP_TRANSLATIONS, NULL))
        {
            guint g, k, i;
            char **groups, **keys, *value, *exec;

            groups = g_key_file_get_groups (state_file, NULL);
            for (g = 0; groups[g]; g++)
            {
                keys = g_key_file_get_keys (state_file, groups[g], NULL, NULL);
                for (k = 0; keys[k]; k++)
                {
                    value = g_key_file_get_value (state_file, groups[g],
                                                  keys[k], NULL);
                    if (value)
                    {
                        g_key_file_set_value (merged_file, groups[g],
                                              keys[k], value);
                        g_free (value);
                    }
                }
                g_strfreev (keys);
            }
            g_strfreev (groups);

            g_key_file_free (state_file);
            state_file = merged_file;

            /* Update Exec key using "--sm-client-state-file %k" */
            restart = generate_command (xsmp->restart_command,
                                        NULL, "%k");
            for (i = 0; i < restart->len; i++)
                restart->pdata[i] = g_shell_quote (restart->pdata[i]);
            g_ptr_array_add (restart, NULL);
            exec = g_strjoinv (" ", (char **)restart->pdata);
            g_strfreev ((char **)restart->pdata);
            g_ptr_array_free (restart, FALSE);

            g_key_file_set_string (state_file, EGG_DESKTOP_FILE_GROUP,
                                   EGG_DESKTOP_FILE_KEY_EXEC,
                                   exec);
            g_free (exec);
        }
        else
            desktop_file = NULL;

        g_free (desktop_file_path);
    }

    /* Now write state_file to disk. (We can't use mktemp(), because
     * that requires the filename to end with "XXXXXX", and we want
     * it to end with ".desktop".)
     */

    data = g_key_file_to_data (state_file, NULL, NULL);
    g_key_file_free (state_file);

    offset = 0;
    while (1)
    {
        state_file_path = g_strdup_printf ("%s%csession-state%c%s-%ld.%s",
                                           g_get_user_config_dir (),
                                           G_DIR_SEPARATOR, G_DIR_SEPARATOR,
                                           g_get_prgname (),
                                           (long)time (NULL) + offset,
                                           desktop_file ? "desktop" : "state");

        fd = open (state_file_path, O_WRONLY | O_CREAT | O_EXCL, 0644);
        if (fd == -1)
        {
            if (errno == EEXIST)
            {
                offset++;
                g_free (state_file_path);
                continue;
            }
            else if (errno == ENOTDIR || errno == ENOENT)
            {
                char *sep = strrchr (state_file_path, G_DIR_SEPARATOR);

                *sep = '\0';
                if (g_mkdir_with_parents (state_file_path, 0755) != 0)
                {
                    g_warning ("Could not create directory '%s'",
                               state_file_path);
                    g_free (state_file_path);
                    state_file_path = NULL;
                    break;
                }

                continue;
            }

            g_warning ("Could not create file '%s': %s",
                       state_file_path, g_strerror (errno));
            g_free (state_file_path);
            state_file_path = NULL;
            break;
        }

        close (fd);
        g_file_set_contents (state_file_path, data, -1, NULL);
        break;
    }
    g_free (data);

    restart = generate_command (xsmp->restart_command, xsmp->client_id,
                                state_file_path);
    set_properties (xsmp,
                    ptrarray_prop (SmRestartCommand, restart),
                    NULL);
    g_ptr_array_free (restart, TRUE);

    if (state_file_path)
    {
        set_properties (xsmp,
                        array_prop (SmDiscardCommand,
                                    "/bin/rm", "-rf", state_file_path,
                                    NULL),
                        NULL);
        g_free (state_file_path);
    }
}

static void
xsmp_interact (SmcConn   smc_conn,
               SmPointer client_data)
{
    EggSMClientXSMP *xsmp = client_data;
    EggSMClient *client = client_data;

    g_debug ("Received Interact message in state %s",
             EGG_SM_CLIENT_XSMP_STATE (xsmp));

    if (xsmp->state != XSMP_STATE_INTERACT_REQUEST)
    {
        fix_broken_state (xsmp, "Interact", TRUE, TRUE);
        return;
    }

    xsmp->state = XSMP_STATE_INTERACT;
    egg_sm_client_quit_requested (client);
}

static void
xsmp_die (SmcConn   smc_conn,
          SmPointer client_data)
{
    EggSMClientXSMP *xsmp = client_data;
    EggSMClient *client = client_data;

    g_debug ("Received Die message in state %s",
             EGG_SM_CLIENT_XSMP_STATE (xsmp));

    sm_client_xsmp_disconnect (xsmp);
    egg_sm_client_quit (client);
}

static void
xsmp_save_complete (SmcConn   smc_conn,
                    SmPointer client_data)
{
    EggSMClientXSMP *xsmp = client_data;

    g_debug ("Received SaveComplete message in state %s",
             EGG_SM_CLIENT_XSMP_STATE (xsmp));

    if (xsmp->state == XSMP_STATE_SAVE_YOURSELF_DONE)
        xsmp->state = XSMP_STATE_IDLE;
    else
        fix_broken_state (xsmp, "SaveComplete", FALSE, FALSE);
}

static void
xsmp_shutdown_cancelled (SmcConn   smc_conn,
                         SmPointer client_data)
{
    EggSMClientXSMP *xsmp = client_data;
    EggSMClient *client = client_data;

    g_debug ("Received ShutdownCancelled message in state %s",
             EGG_SM_CLIENT_XSMP_STATE (xsmp));

    xsmp->shutting_down = FALSE;

    if (xsmp->state == XSMP_STATE_SAVE_YOURSELF_DONE)
    {
        /* We've finished interacting and now the SM has agreed to
         * cancel the shutdown.
         */
        xsmp->state = XSMP_STATE_IDLE;
        egg_sm_client_quit_cancelled (client);
    }
    else if (xsmp->state == XSMP_STATE_SHUTDOWN_CANCELLED)
    {
        /* Hm... ok, so we got a shutdown SaveYourself, which got
         * cancelled, but the application was still interacting, so we
         * didn't tell it yet, and then *another* SaveYourself arrived,
         * which we must still be waiting to tell the app about, except
         * that now that SaveYourself has been cancelled too! Dizzy yet?
         */
        xsmp->waiting_to_save_myself = FALSE;
        update_pending_events (xsmp);
    }
    else
    {
        g_debug ("Sending SaveYourselfDone(False)");
        SmcSaveYourselfDone (xsmp->connection, False);

        if (xsmp->state == XSMP_STATE_INTERACT)
        {
            /* The application is currently interacting, so we can't
             * tell it about the cancellation yet; we will wait until
             * after it calls egg_sm_client_will_quit().
             */
            xsmp->state = XSMP_STATE_SHUTDOWN_CANCELLED;
        }
        else
        {
            /* The shutdown was cancelled before the application got a
             * chance to interact.
             */
            xsmp->state = XSMP_STATE_IDLE;
        }
    }
}

/* Utilities */

/* Create a restart/clone/Exec command based on @restart_command.
 * If @client_id is non-%NULL, add "--sm-client-id @client_id".
 * If @state_file is non-%NULL, add "--sm-client-state-file @state_file".
 *
 * None of the input strings are g_strdup()ed; the caller must keep
 * them around until it is done with the returned GPtrArray, and must
 * then free the array, but not its contents.
 */
static GPtrArray *
generate_command (char **restart_command, const char *client_id,
                  const char *state_file)
{
    GPtrArray *cmd;
    int i;

    cmd = g_ptr_array_new ();
    g_ptr_array_add (cmd, restart_command[0]);

    if (client_id)
    {
        g_ptr_array_add (cmd, "--sm-client-id");
        g_ptr_array_add (cmd, (char *)client_id);
    }

    if (state_file)
    {
        g_ptr_array_add (cmd, "--sm-client-state-file");
        g_ptr_array_add (cmd, (char *)state_file);
    }

    for (i = 1; restart_command[i]; i++)
        g_ptr_array_add (cmd, restart_command[i]);

    return cmd;
}

/* Takes a NULL-terminated list of SmProp * values, created by
 * array_prop, ptrarray_prop, string_prop, card8_prop, sets them, and
 * frees them.
 */
static void
set_properties (EggSMClientXSMP *xsmp, ...)
{
    GPtrArray *props;
    SmProp *prop;
    va_list ap;
    guint i;

    props = g_ptr_array_new ();

    va_start (ap, xsmp);
    while ((prop = va_arg (ap, SmProp *)))
        g_ptr_array_add (props, prop);
    va_end (ap);

    if (xsmp->connection)
    {
        SmcSetProperties (xsmp->connection, props->len,
                          (SmProp **)props->pdata);
    }

    for (i = 0; i < props->len; i++)
    {
        prop = props->pdata[i];
        g_free (prop->vals);
        g_free (prop);
    }
    g_ptr_array_free (props, TRUE);
}

/* Takes a NULL-terminated list of property names and deletes them. */
static void
delete_properties (EggSMClientXSMP *xsmp, ...)
{
    GPtrArray *props;
    char *prop;
    va_list ap;

    if (!xsmp->connection)
        return;

    props = g_ptr_array_new ();

    va_start (ap, xsmp);
    while ((prop = va_arg (ap, char *)))
        g_ptr_array_add (props, prop);
    va_end (ap);

    SmcDeleteProperties (xsmp->connection, props->len,
                         (char **)props->pdata);

    g_ptr_array_free (props, TRUE);
}

/* Takes an array of strings and creates a LISTofARRAY8 property. The
 * strings are neither dupped nor freed; they need to remain valid
 * until you're done with the SmProp.
 */
static SmProp *
array_prop (const char *name, ...)
{
    SmProp *prop;
    SmPropValue pv;
    GArray *vals;
    char *value;
    va_list ap;

    prop = g_new (SmProp, 1);
    prop->name = (char *)name;
    prop->type = SmLISTofARRAY8;

    vals = g_array_new (FALSE, FALSE, sizeof (SmPropValue));

    va_start (ap, name);
    while ((value = va_arg (ap, char *)))
    {
        pv.length = strlen (value);
        pv.value = value;
        g_array_append_val (vals, pv);
    }
    va_end (ap);

    prop->num_vals = vals->len;
    prop->vals = (SmPropValue *)vals->data;

    g_array_free (vals, FALSE);

    return prop;
}

/* Takes a GPtrArray of strings and creates a LISTofARRAY8 property.
 * The array contents are neither dupped nor freed; they need to
 * remain valid until you're done with the SmProp.
 */
static SmProp *
ptrarray_prop (const char *name, GPtrArray *values)
{
    SmProp *prop;
    SmPropValue pv;
    GArray *vals;
    guint i;

    prop = g_new (SmProp, 1);
    prop->name = (char *)name;
    prop->type = SmLISTofARRAY8;

    vals = g_array_new (FALSE, FALSE, sizeof (SmPropValue));

    for (i = 0; i < values->len; i++)
    {
        pv.length = strlen (values->pdata[i]);
        pv.value = values->pdata[i];
        g_array_append_val (vals, pv);
    }

    prop->num_vals = vals->len;
    prop->vals = (SmPropValue *)vals->data;

    g_array_free (vals, FALSE);

    return prop;
}

/* Takes a string and creates an ARRAY8 property. The string is
 * neither dupped nor freed; it needs to remain valid until you're
 * done with the SmProp.
 */
static SmProp *
string_prop (const char *name, const char *value)
{
    SmProp *prop;

    prop = g_new (SmProp, 1);
    prop->name = (char *)name;
    prop->type = SmARRAY8;

    prop->num_vals = 1;
    prop->vals = g_new (SmPropValue, 1);

    prop->vals[0].length = strlen (value);
    prop->vals[0].value = (char *)value;

    return prop;
}

/* Takes a char and creates a CARD8 property. */
static SmProp *
card8_prop (const char *name, unsigned char value)
{
    SmProp *prop;
    char *card8val;

    /* To avoid having to allocate and free prop->vals[0], we cheat and
     * make vals a 2-element-long array and then use the second element
     * to store value.
     */

    prop = g_new (SmProp, 1);
    prop->name = (char *)name;
    prop->type = SmCARD8;

    prop->num_vals = 1;
    prop->vals = g_new (SmPropValue, 2);
    card8val = (char *)(&prop->vals[1]);
    card8val[0] = value;

    prop->vals[0].length = 1;
    prop->vals[0].value = card8val;

    return prop;
}

/* ICE code. This makes no effort to play nice with anyone else trying
 * to use libICE. Fortunately, no one uses libICE for anything other
 * than SM. (DCOP uses ICE, but it has its own private copy of
 * libICE.)
 *
 * When this moves to gtk, it will need to be cleverer, to avoid
 * tripping over old apps that use MateClient or that use libSM
 * directly.
 */

#include <X11/ICE/ICElib.h>
#include <fcntl.h>

static void        ice_error_handler    (IceConn        ice_conn,
        Bool           swap,
        int            offending_minor_opcode,
        unsigned long  offending_sequence,
        int            error_class,
        int            severity,
        IcePointer     values);
static void        ice_io_error_handler (IceConn        ice_conn);
static void        ice_connection_watch (IceConn        ice_conn,
        IcePointer     client_data,
        Bool           opening,
        IcePointer    *watch_data);

static void
ice_init (void)
{
    IceSetIOErrorHandler (ice_io_error_handler);
    IceSetErrorHandler (ice_error_handler);
    IceAddConnectionWatch (ice_connection_watch, NULL);
}

static gboolean
process_ice_messages (IceConn ice_conn)
{
    IceProcessMessagesStatus status;
#if GTK_CHECK_VERSION (3, 0, 0)
    status = IceProcessMessages (ice_conn, NULL, NULL);
#else
    gdk_threads_enter ();
    status = IceProcessMessages (ice_conn, NULL, NULL);
    gdk_threads_leave ();
#endif

    switch (status)
    {
    case IceProcessMessagesSuccess:
        return TRUE;

    case IceProcessMessagesIOError:
        sm_client_xsmp_disconnect (IceGetConnectionContext (ice_conn));
        return FALSE;

    case IceProcessMessagesConnectionClosed:
        return FALSE;

    default:
        g_assert_not_reached ();
    }
}

static gboolean
ice_iochannel_watch (GIOChannel   *channel,
                     GIOCondition  condition,
                     gpointer      client_data)
{
    return process_ice_messages (client_data);
}

static void
ice_connection_watch (IceConn     ice_conn,
                      IcePointer  client_data,
                      Bool        opening,
                      IcePointer *watch_data)
{
    guint watch_id;

    if (opening)
    {
        GIOChannel *channel;
        int fd = IceConnectionNumber (ice_conn);

        fcntl (fd, F_SETFD, fcntl (fd, F_GETFD, 0) | FD_CLOEXEC);
        channel = g_io_channel_unix_new (fd);
        watch_id = g_io_add_watch (channel, G_IO_IN | G_IO_ERR,
                                   ice_iochannel_watch, ice_conn);
        g_io_channel_unref (channel);

        *watch_data = GUINT_TO_POINTER (watch_id);
    }
    else
    {
        watch_id = GPOINTER_TO_UINT (*watch_data);
        g_source_remove (watch_id);
    }
}

static void
ice_error_handler (IceConn       ice_conn,
                   Bool          swap,
                   int           offending_minor_opcode,
                   unsigned long offending_sequence,
                   int           error_class,
                   int           severity,
                   IcePointer    values)
{
    /* Do nothing */
}

static void
ice_io_error_handler (IceConn ice_conn)
{
    /* Do nothing */
}

static void
smc_error_handler (SmcConn       smc_conn,
                   Bool          swap,
                   int           offending_minor_opcode,
                   unsigned long offending_sequence,
                   int           error_class,
                   int           severity,
                   SmPointer     values)
{
    /* Do nothing */
}
