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[mono-project.git] / mono / io-layer / wait.c

/*
 * wait.c:  wait for handles to become signalled
 *
 * Author:
 *      Dick Porter (dick@ximian.com)
 *
 * (C) 2002-2006 Novell, Inc.
 */

#include <config.h>
#include <glib.h>
#include <string.h>
#include <errno.h>

#include <mono/io-layer/wapi.h>
#include <mono/io-layer/handles-private.h>
#include <mono/io-layer/wapi-private.h>
#include <mono/io-layer/mono-mutex.h>
#include <mono/io-layer/misc-private.h>

#if 0
#define DEBUG(...) g_message(__VA_ARGS__)
#else
#define DEBUG(...)
#endif

static gboolean own_if_signalled(gpointer handle)
{
        gboolean ret = FALSE;
        
        if (_WAPI_SHARED_HANDLE (_wapi_handle_type (handle))) {
                if (_wapi_handle_trylock_shared_handles () == EBUSY) {
                        return (FALSE);
                }
        }
        
        if (_wapi_handle_issignalled (handle)) {
                _wapi_handle_ops_own (handle);
                ret = TRUE;
        }

        if (_WAPI_SHARED_HANDLE (_wapi_handle_type (handle))) {
                _wapi_handle_unlock_shared_handles ();
        }

        return(ret);
}

static gboolean own_if_owned(gpointer handle)
{
        gboolean ret = FALSE;
        
        if (_WAPI_SHARED_HANDLE (_wapi_handle_type (handle))) {
                if (_wapi_handle_trylock_shared_handles () == EBUSY) {
                        return (FALSE);
                }
        }
        
        if (_wapi_handle_ops_isowned (handle)) {
                _wapi_handle_ops_own (handle);
                ret = TRUE;
        }

        if (_WAPI_SHARED_HANDLE (_wapi_handle_type (handle))) {
                _wapi_handle_unlock_shared_handles ();
        }

        return(ret);
}

/**
 * WaitForSingleObjectEx:
 * @handle: an object to wait for
 * @timeout: the maximum time in milliseconds to wait for
 * @alertable: if TRUE, the wait can be interrupted by an APC call
 *
 * This function returns when either @handle is signalled, or @timeout
 * ms elapses.  If @timeout is zero, the object's state is tested and
 * the function returns immediately.  If @timeout is %INFINITE, the
 * function waits forever.
 *
 * Return value: %WAIT_ABANDONED - @handle is a mutex that was not
 * released by the owning thread when it exited.  Ownership of the
 * mutex object is granted to the calling thread and the mutex is set
 * to nonsignalled.  %WAIT_OBJECT_0 - The state of @handle is
 * signalled.  %WAIT_TIMEOUT - The @timeout interval elapsed and
 * @handle's state is still not signalled.  %WAIT_FAILED - an error
 * occurred. %WAIT_IO_COMPLETION - the wait was ended by an APC.
 */
guint32 WaitForSingleObjectEx(gpointer handle, guint32 timeout,
                              gboolean alertable)
{
        guint32 ret, waited;
        struct timespec abstime;
        int thr_ret;
        gboolean apc_pending = FALSE;
        gpointer current_thread = _wapi_thread_handle_from_id (pthread_self ());
        
        if (current_thread == NULL) {
                SetLastError (ERROR_INVALID_HANDLE);
                return(WAIT_FAILED);
        }

        if (handle == _WAPI_THREAD_CURRENT) {
                handle = _wapi_thread_handle_from_id (pthread_self ());
                if (handle == NULL) {
                        SetLastError (ERROR_INVALID_HANDLE);
                        return(WAIT_FAILED);
                }
        }

        if ((GPOINTER_TO_UINT (handle) & _WAPI_PROCESS_UNHANDLED) == _WAPI_PROCESS_UNHANDLED) {
                SetLastError (ERROR_INVALID_HANDLE);
                return(WAIT_FAILED);
        }
        
        if (_wapi_handle_test_capabilities (handle,
                                            WAPI_HANDLE_CAP_WAIT) == FALSE) {
                DEBUG ("%s: handle %p can't be waited for", __func__,
                           handle);

                return(WAIT_FAILED);
        }

        _wapi_handle_ops_prewait (handle);
        
        if (_wapi_handle_test_capabilities (handle, WAPI_HANDLE_CAP_SPECIAL_WAIT) == TRUE) {
                DEBUG ("%s: handle %p has special wait", __func__, handle);

                ret = _wapi_handle_ops_special_wait (handle, timeout, alertable);
        
                if (alertable && _wapi_thread_apc_pending (current_thread)) {
                        apc_pending = TRUE;
                        ret = WAIT_IO_COMPLETION;
                }

                goto check_pending;
        }
        
        
        DEBUG ("%s: locking handle %p", __func__, handle);

        pthread_cleanup_push ((void(*)(void *))_wapi_handle_unlock_handle,
                              handle);
        thr_ret = _wapi_handle_lock_handle (handle);
        g_assert (thr_ret == 0);

        if (_wapi_handle_test_capabilities (handle,
                                            WAPI_HANDLE_CAP_OWN) == TRUE) {
                if (own_if_owned (handle) == TRUE) {
                        DEBUG ("%s: handle %p already owned", __func__,
                                   handle);
                        ret = WAIT_OBJECT_0;
                        goto done;
                }
        }
        
        if (alertable && _wapi_thread_apc_pending (current_thread)) {
                apc_pending = TRUE;
                ret = WAIT_IO_COMPLETION;
                goto done;
        }
        
        if (own_if_signalled (handle) == TRUE) {
                DEBUG ("%s: handle %p already signalled", __func__,
                           handle);

                ret=WAIT_OBJECT_0;
                goto done;
        }

        if (timeout == 0) {
                ret = WAIT_TIMEOUT;
                goto done;
        }
        /* Have to wait for it */
        if (timeout != INFINITE) {
                _wapi_calc_timeout (&abstime, timeout);
        }
        
        do {
                /* Check before waiting on the condition, just in case
                 */
                _wapi_handle_ops_prewait (handle);

                if (own_if_signalled (handle)) {
                        DEBUG ("%s: handle %p signalled", __func__,
                                   handle);

                        ret = WAIT_OBJECT_0;
                        goto done;
                }
                        
                if (timeout == INFINITE) {
                        waited = _wapi_handle_wait_signal_handle (handle, alertable);
                } else {
                        waited = _wapi_handle_timedwait_signal_handle (handle, &abstime, alertable, FALSE);
                }
        
                if (alertable)
                        apc_pending = _wapi_thread_apc_pending (current_thread);

                if(waited==0 && !apc_pending) {
                        /* Condition was signalled, so hopefully
                         * handle is signalled now.  (It might not be
                         * if someone else got in before us.)
                         */
                        if (own_if_signalled (handle)) {
                                DEBUG ("%s: handle %p signalled", __func__,
                                           handle);

                                ret=WAIT_OBJECT_0;
                                goto done;
                        }
                
                        /* Better luck next time */
                }
        } while(waited == 0 && !apc_pending);

        /* Timeout or other error */
        DEBUG ("%s: wait on handle %p error: %s", __func__, handle,
                   strerror (waited));

        ret = WAIT_TIMEOUT;
        
done:

        DEBUG ("%s: unlocking handle %p", __func__, handle);
        
        thr_ret = _wapi_handle_unlock_handle (handle);
        g_assert (thr_ret == 0);
        pthread_cleanup_pop (0);
        
check_pending:
        if (apc_pending) {
                _wapi_thread_dispatch_apc_queue (current_thread);
                ret = WAIT_IO_COMPLETION;
        }
                
        return(ret);
}

guint32 WaitForSingleObject(gpointer handle, guint32 timeout)
{
        return WaitForSingleObjectEx (handle, timeout, FALSE);
}


/**
 * SignalObjectAndWait:
 * @signal_handle: An object to signal
 * @wait: An object to wait for
 * @timeout: The maximum time in milliseconds to wait for
 * @alertable: Specifies whether the function returnes when the system
 * queues an I/O completion routine or an APC for the calling thread.
 *
 * Atomically signals @signal and waits for @wait to become signalled,
 * or @timeout ms elapses.  If @timeout is zero, the object's state is
 * tested and the function returns immediately.  If @timeout is
 * %INFINITE, the function waits forever.
 *
 * @signal can be a semaphore, mutex or event object.
 *
 * If @alertable is %TRUE and the system queues an I/O completion
 * routine or an APC for the calling thread, the function returns and
 * the thread calls the completion routine or APC function.  If
 * %FALSE, the function does not return, and the thread does not call
 * the completion routine or APC function.  A completion routine is
 * queued when the ReadFileEx() or WriteFileEx() function in which it
 * was specified has completed.  The calling thread is the thread that
 * initiated the read or write operation.  An APC is queued when
 * QueueUserAPC() is called.  Currently completion routines and APC
 * functions are not supported.
 *
 * Return value: %WAIT_ABANDONED - @wait is a mutex that was not
 * released by the owning thread when it exited.  Ownershop of the
 * mutex object is granted to the calling thread and the mutex is set
 * to nonsignalled.  %WAIT_IO_COMPLETION - the wait was ended by one
 * or more user-mode asynchronous procedure calls queued to the
 * thread.  %WAIT_OBJECT_0 - The state of @wait is signalled.
 * %WAIT_TIMEOUT - The @timeout interval elapsed and @wait's state is
 * still not signalled.  %WAIT_FAILED - an error occurred.
 */
guint32 SignalObjectAndWait(gpointer signal_handle, gpointer wait,
                            guint32 timeout, gboolean alertable)
{
        guint32 ret, waited;
        struct timespec abstime;
        int thr_ret;
        gboolean apc_pending = FALSE;
        gpointer current_thread = _wapi_thread_handle_from_id (pthread_self ());
        
        if (current_thread == NULL) {
                SetLastError (ERROR_INVALID_HANDLE);
                return(WAIT_FAILED);
        }

        if (signal_handle == _WAPI_THREAD_CURRENT) {
                signal_handle = _wapi_thread_handle_from_id (pthread_self ());
                if (signal_handle == NULL) {
                        SetLastError (ERROR_INVALID_HANDLE);
                        return(WAIT_FAILED);
                }
        }

        if (wait == _WAPI_THREAD_CURRENT) {
                wait = _wapi_thread_handle_from_id (pthread_self ());
                if (wait == NULL) {
                        SetLastError (ERROR_INVALID_HANDLE);
                        return(WAIT_FAILED);
                }
        }

        if ((GPOINTER_TO_UINT (signal_handle) & _WAPI_PROCESS_UNHANDLED) == _WAPI_PROCESS_UNHANDLED) {
                SetLastError (ERROR_INVALID_HANDLE);
                return(WAIT_FAILED);
        }

        if ((GPOINTER_TO_UINT (wait) & _WAPI_PROCESS_UNHANDLED) == _WAPI_PROCESS_UNHANDLED) {
                SetLastError (ERROR_INVALID_HANDLE);
                return(WAIT_FAILED);
        }
        
        if (_wapi_handle_test_capabilities (signal_handle,
                                            WAPI_HANDLE_CAP_SIGNAL)==FALSE) {
                return(WAIT_FAILED);
        }
        
        if (_wapi_handle_test_capabilities (wait,
                                            WAPI_HANDLE_CAP_WAIT)==FALSE) {
                return(WAIT_FAILED);
        }

        _wapi_handle_ops_prewait (wait);
        
        if (_wapi_handle_test_capabilities (wait, WAPI_HANDLE_CAP_SPECIAL_WAIT) == TRUE) {
                g_warning ("%s: handle %p has special wait, implement me!!",
                           __func__, wait);

                return (WAIT_FAILED);
        }

        DEBUG ("%s: locking handle %p", __func__, wait);

        pthread_cleanup_push ((void(*)(void *))_wapi_handle_unlock_handle,
                              wait);
        thr_ret = _wapi_handle_lock_handle (wait);
        g_assert (thr_ret == 0);

        _wapi_handle_ops_signal (signal_handle);

        if (_wapi_handle_test_capabilities (wait, WAPI_HANDLE_CAP_OWN)==TRUE) {
                if (own_if_owned (wait)) {
                        DEBUG ("%s: handle %p already owned", __func__,
                                   wait);
                        ret = WAIT_OBJECT_0;
                        goto done;
                }
        }
        
        if (alertable && _wapi_thread_apc_pending (current_thread)) {
                apc_pending = TRUE;
                ret = WAIT_IO_COMPLETION;
                goto done;
        }
        
        if (own_if_signalled (wait)) {
                DEBUG ("%s: handle %p already signalled", __func__, wait);

                ret = WAIT_OBJECT_0;
                goto done;
        }

        /* Have to wait for it */
        if (timeout != INFINITE) {
                _wapi_calc_timeout (&abstime, timeout);
        }
        
        do {
                /* Check before waiting on the condition, just in case
                 */
                _wapi_handle_ops_prewait (wait);
        
                if (own_if_signalled (wait)) {
                        DEBUG ("%s: handle %p signalled", __func__, wait);

                        ret = WAIT_OBJECT_0;
                        goto done;
                }
                
                if (timeout == INFINITE) {
                        waited = _wapi_handle_wait_signal_handle (wait, alertable);
                } else {
                        waited = _wapi_handle_timedwait_signal_handle (wait, &abstime, alertable, FALSE);
                }

                if (alertable) {
                        apc_pending = _wapi_thread_apc_pending (current_thread);
                }

                if (waited==0 && !apc_pending) {
                        /* Condition was signalled, so hopefully
                         * handle is signalled now.  (It might not be
                         * if someone else got in before us.)
                         */
                        if (own_if_signalled (wait)) {
                                DEBUG ("%s: handle %p signalled", __func__,
                                           wait);

                                ret = WAIT_OBJECT_0;
                                goto done;
                        }
                
                        /* Better luck next time */
                }
        } while(waited == 0 && !apc_pending);

        /* Timeout or other error */
        DEBUG ("%s: wait on handle %p error: %s", __func__, wait,
                   strerror (ret));

        ret = WAIT_TIMEOUT;
        
done:

        DEBUG ("%s: unlocking handle %p", __func__, wait);

        thr_ret = _wapi_handle_unlock_handle (wait);
        g_assert (thr_ret == 0);
        pthread_cleanup_pop (0);

        if (apc_pending) {
                _wapi_thread_dispatch_apc_queue (current_thread);
                ret = WAIT_IO_COMPLETION;
        }
        
        return(ret);
}

struct handle_cleanup_data
{
        guint32 numobjects;
        gpointer *handles;
};

static void handle_cleanup (void *data)
{
        struct handle_cleanup_data *handles = (struct handle_cleanup_data *)data;

        _wapi_handle_unlock_handles (handles->numobjects, handles->handles);
}

static gboolean test_and_own (guint32 numobjects, gpointer *handles,
                              gboolean waitall, guint32 *count,
                              guint32 *lowest)
{
        struct handle_cleanup_data cleanup_data;
        gboolean done;
        int i;
        
        DEBUG ("%s: locking handles", __func__);
        cleanup_data.numobjects = numobjects;
        cleanup_data.handles = handles;
        
        pthread_cleanup_push (handle_cleanup, (void *)&cleanup_data);
        done = _wapi_handle_count_signalled_handles (numobjects, handles,
                                                     waitall, count, lowest);
        if (done == TRUE) {
                if (waitall == TRUE) {
                        for (i = 0; i < numobjects; i++) {
                                own_if_signalled (handles[i]);
                        }
                } else {
                        own_if_signalled (handles[*lowest]);
                }
        }
        
        DEBUG ("%s: unlocking handles", __func__);

        /* calls the unlock function */
        pthread_cleanup_pop (1);

        return(done);
}

/**
 * WaitForMultipleObjectsEx:
 * @numobjects: The number of objects in @handles. The maximum allowed
 * is %MAXIMUM_WAIT_OBJECTS.
 * @handles: An array of object handles.  Duplicates are not allowed.
 * @waitall: If %TRUE, this function waits until all of the handles
 * are signalled.  If %FALSE, this function returns when any object is
 * signalled.
 * @timeout: The maximum time in milliseconds to wait for.
 * @alertable: if TRUE, the wait can be interrupted by an APC call
 * 
 * This function returns when either one or more of @handles is
 * signalled, or @timeout ms elapses.  If @timeout is zero, the state
 * of each item of @handles is tested and the function returns
 * immediately.  If @timeout is %INFINITE, the function waits forever.
 *
 * Return value: %WAIT_OBJECT_0 to %WAIT_OBJECT_0 + @numobjects - 1 -
 * if @waitall is %TRUE, indicates that all objects are signalled.  If
 * @waitall is %FALSE, the return value minus %WAIT_OBJECT_0 indicates
 * the first index into @handles of the objects that are signalled.
 * %WAIT_ABANDONED_0 to %WAIT_ABANDONED_0 + @numobjects - 1 - if
 * @waitall is %TRUE, indicates that all objects are signalled, and at
 * least one object is an abandoned mutex object (See
 * WaitForSingleObject() for a description of abandoned mutexes.)  If
 * @waitall is %FALSE, the return value minus %WAIT_ABANDONED_0
 * indicates the first index into @handles of an abandoned mutex.
 * %WAIT_TIMEOUT - The @timeout interval elapsed and no objects in
 * @handles are signalled.  %WAIT_FAILED - an error occurred.
 * %WAIT_IO_COMPLETION - the wait was ended by an APC.
 */
guint32 WaitForMultipleObjectsEx(guint32 numobjects, gpointer *handles,
                                 gboolean waitall, guint32 timeout,
                                 gboolean alertable)
{
        gboolean duplicate = FALSE, bogustype = FALSE, done;
        guint32 count, lowest;
        struct timespec abstime;
        guint i;
        guint32 ret;
        int thr_ret;
        gpointer current_thread = _wapi_thread_handle_from_id (pthread_self ());
        guint32 retval;
        gboolean poll;
        gpointer sorted_handles [MAXIMUM_WAIT_OBJECTS];
        
        if (current_thread == NULL) {
                SetLastError (ERROR_INVALID_HANDLE);
                return(WAIT_FAILED);
        }
        
        if (numobjects > MAXIMUM_WAIT_OBJECTS) {
                DEBUG ("%s: Too many handles: %d", __func__, numobjects);

                return(WAIT_FAILED);
        }
        
        if (numobjects == 1) {
                return WaitForSingleObjectEx (handles [0], timeout, alertable);
        }

        /* Check for duplicates */
        for (i = 0; i < numobjects; i++) {
                if (handles[i] == _WAPI_THREAD_CURRENT) {
                        handles[i] = _wapi_thread_handle_from_id (pthread_self ());
                        
                        if (handles[i] == NULL) {
                                DEBUG ("%s: Handle %d bogus", __func__, i);

                                bogustype = TRUE;
                                break;
                        }
                }

                if ((GPOINTER_TO_UINT (handles[i]) & _WAPI_PROCESS_UNHANDLED) == _WAPI_PROCESS_UNHANDLED) {
                        DEBUG ("%s: Handle %d pseudo process", __func__,
                                   i);

                        bogustype = TRUE;
                        break;
                }

                if (_wapi_handle_test_capabilities (handles[i], WAPI_HANDLE_CAP_WAIT) == FALSE) {
                        DEBUG ("%s: Handle %p can't be waited for",
                                   __func__, handles[i]);

                        bogustype = TRUE;
                        break;
                }

                sorted_handles [i] = handles [i];
                _wapi_handle_ops_prewait (handles[i]);
        }

        qsort (sorted_handles, numobjects, sizeof (gpointer), g_direct_equal);
        for (i = 1; i < numobjects; i++) {
                if (sorted_handles [i - 1] == sorted_handles [i]) {
                        duplicate = TRUE;
                        break;
                }
        }

        if (duplicate == TRUE) {
                DEBUG ("%s: Returning due to duplicates", __func__);

                return(WAIT_FAILED);
        }

        if (bogustype == TRUE) {
                DEBUG ("%s: Returning due to bogus type", __func__);

                return(WAIT_FAILED);
        }

        poll = FALSE;
        for (i = 0; i < numobjects; ++i)
                if (_wapi_handle_type (handles [i]) == WAPI_HANDLE_PROCESS || _WAPI_SHARED_HANDLE (_wapi_handle_type (handles[i]))) 
                        /* Can't wait for a process handle + another handle without polling */
                        poll = TRUE;

        done = test_and_own (numobjects, handles, waitall, &count, &lowest);
        if (done == TRUE) {
                return(WAIT_OBJECT_0+lowest);
        }
        
        if (timeout == 0) {
                return WAIT_TIMEOUT;
        }
        /* Have to wait for some or all handles to become signalled
         */

        if(timeout!=INFINITE) {
                _wapi_calc_timeout (&abstime, timeout);
        }

        if (alertable && _wapi_thread_apc_pending (current_thread)) {
                _wapi_thread_dispatch_apc_queue (current_thread);
                return WAIT_IO_COMPLETION;
        }
        
        for (i = 0; i < numobjects; i++) {
                /* Add a reference, as we need to ensure the handle wont
                 * disappear from under us while we're waiting in the loop
                 * (not lock, as we don't want exclusive access here)
                 */
                _wapi_handle_ref (handles[i]);
        }

        while(1) {
                /* Prod all handles with prewait methods and
                 * special-wait handles that aren't already signalled
                 */
                for (i = 0; i < numobjects; i++) {
                        _wapi_handle_ops_prewait (handles[i]);
                
                        if (_wapi_handle_test_capabilities (handles[i], WAPI_HANDLE_CAP_SPECIAL_WAIT) == TRUE && _wapi_handle_issignalled (handles[i]) == FALSE) {
                                _wapi_handle_ops_special_wait (handles[i], 0, alertable);
                        }
                }
                
                DEBUG ("%s: locking signal mutex", __func__);

                pthread_cleanup_push ((void(*)(void *))_wapi_handle_unlock_signal_mutex, NULL);
                thr_ret = _wapi_handle_lock_signal_mutex ();
                g_assert (thr_ret == 0);

                /* Check the signalled state of handles inside the critical section */
                if (waitall) {
                        done = TRUE;
                        for (i = 0; i < numobjects; i++)
                                if (!_wapi_handle_issignalled (handles [i]))
                                        done = FALSE;
                } else {
                        done = FALSE;
                        for (i = 0; i < numobjects; i++)
                                if (_wapi_handle_issignalled (handles [i]))
                                        done = TRUE;
                }
                
                if (!done) {
                        /* Enter the wait */
                        if (timeout == INFINITE) {
                                ret = _wapi_handle_wait_signal (poll);
                        } else {
                                ret = _wapi_handle_timedwait_signal (&abstime, poll);
                        }
                } else {
                        /* No need to wait */
                        ret = 0;
                }

                DEBUG ("%s: unlocking signal mutex", __func__);

                thr_ret = _wapi_handle_unlock_signal_mutex (NULL);
                g_assert (thr_ret == 0);
                pthread_cleanup_pop (0);
                
                if (alertable && _wapi_thread_apc_pending (current_thread)) {
                        _wapi_thread_dispatch_apc_queue (current_thread);
                        retval = WAIT_IO_COMPLETION;
                        break;
                }
        
                /* Check if everything is signalled, as we can't
                 * guarantee to notice a shared signal even if the
                 * wait timed out
                 */
                done = test_and_own (numobjects, handles, waitall,
                                     &count, &lowest);
                if (done == TRUE) {
                        retval = WAIT_OBJECT_0+lowest;
                        break;
                } else if (ret != 0) {
                        /* Didn't get all handles, and there was a
                         * timeout or other error
                         */
                        DEBUG ("%s: wait returned error: %s", __func__,
                                   strerror (ret));

                        if(ret==ETIMEDOUT) {
                                retval = WAIT_TIMEOUT;
                        } else {
                                retval = WAIT_FAILED;
                        }
                        break;
                }
        }

        for (i = 0; i < numobjects; i++) {
                /* Unref everything we reffed above */
                _wapi_handle_unref (handles[i]);
        }

        return retval;
}

guint32 WaitForMultipleObjects(guint32 numobjects, gpointer *handles,
                               gboolean waitall, guint32 timeout)
{
        return WaitForMultipleObjectsEx(numobjects, handles, waitall, timeout, FALSE);
}

/**
 * WaitForInputIdle:
 * @handle: a handle to the process to wait for
 * @timeout: the maximum time in milliseconds to wait for
 *
 * This function returns when either @handle process is waiting
 * for input, or @timeout ms elapses.  If @timeout is zero, the
 * process state is tested and the function returns immediately.
 * If @timeout is %INFINITE, the function waits forever.
 *
 * Return value: 0 - @handle process is waiting for input.
 * %WAIT_TIMEOUT - The @timeout interval elapsed and
 * @handle process is not waiting for input.  %WAIT_FAILED - an error
 * occurred. 
 */
guint32 WaitForInputIdle(gpointer handle, guint32 timeout)
{
        /*TODO: Not implemented*/
        return WAIT_TIMEOUT;
}