/*
 * This file Copyright (C) 2007 Charles Kerr <charles@rebelbase.com>
 *
 * This file is licensed by the GPL version 2.  Works owned by the
 * Transmission project are granted a special exemption to clause 2(b)
 * so that the bulk of its code can remain under the MIT license. 
 * This exemption does not extend to derived works not owned by
 * the Transmission project.
 */

#include <assert.h>

#include <sys/types.h> /* u_char for event.h */
#include <event.h>

#include "transmission.h"
#include "timer.h"
#include "utils.h"

typedef int tr_timer_func ( void * user_data );
typedef void tr_data_free_func( void * user_data );

/***
****
***/

struct timer_node
{
    struct event event;
    tr_timer_func * func;
    void * user_data;
    tr_data_free_func * free_func;
    struct timeval tv;
    int refcount;
};

static void
unref( struct timer_node * node, int count )
{
    assert( node != NULL );
    assert( node->refcount > 0 );

    node->refcount -= count;
    if( node->refcount > 0 )
        return;

    if( node->free_func != NULL )
        (node->free_func)( node->user_data );
    event_del( &node->event );
    tr_free( node );
}

void
tr_timerFree( struct timer_node ** node )
{
    assert( node != NULL );

    if( *node )
    {
        unref( *node, 1 );
        *node = NULL;
    }
}

static void
timerCB( int fd UNUSED, short event UNUSED, void * arg )
{
    struct timer_node * node = (struct timer_node *) arg;
    int val;

    ++node->refcount;
    val = (node->func)(node->user_data);
    if( !val )
        unref( node, 2 );
    else {
        timeout_add( &node->event, &node->tv );
        unref( node, 1 );
    }
}


tr_timer_tag
tr_timerNew( tr_timer_func        func,
             void               * user_data,
             tr_data_free_func    free_func,
             int                  timeout_milliseconds )
{
    struct timer_node * node;
    const unsigned long microseconds = timeout_milliseconds * 1000;

    assert( func != NULL );
    assert( timeout_milliseconds >= 0 );

    node = tr_new( struct timer_node, 1 );
    node->func = func;
    node->user_data = user_data;
    node->free_func = free_func;
    node->refcount = 1;
    node->tv.tv_sec  = microseconds / 1000000;
    node->tv.tv_usec = microseconds % 1000000;
    timeout_set( &node->event, timerCB, node );
    timeout_add( &node->event, &node->tv );
    return node;
}