objects.c

VLC Player Source Code

#endif

    vlc_spin_lock( &internals->ref_spin );
    assert( internals->i_refcount > 0 );

    if( internals->i_refcount > 1 )
    {
        /* Fast path */
        /* There are still other references to the object */
        internals->i_refcount--;
        vlc_spin_unlock( &internals->ref_spin );
        return;
    }
    vlc_spin_unlock( &internals->ref_spin );

    /* Slow path */
    /* Remember that we cannot hold the spin while waiting on the mutex */
    vlc_mutex_lock( &structure_lock );
    /* Take the spin again. Note that another thread may have yielded the
     * object in the (very short) mean time. */
    vlc_spin_lock( &internals->ref_spin );
    b_should_destroy = --internals->i_refcount == 0;
    vlc_spin_unlock( &internals->ref_spin );

    if( b_should_destroy )
    {
        /* Remove the object from object list
         * so that it cannot be encountered by vlc_object_get() */
        vlc_internals (internals->next)->prev = internals->prev;
        vlc_internals (internals->prev)->next = internals->next;

        /* Detach from parent to protect against FIND_CHILDREN */
        vlc_object_detach_unlocked (p_this);
        /* Detach from children to protect against FIND_PARENT */
        for (int i = 0; i < internals->i_children; i++)
            internals->pp_children[i]->p_parent = NULL;
    }

    vlc_mutex_unlock( &structure_lock );

    if( b_should_destroy )
    {
        free( internals->pp_children );
        internals->pp_children = NULL;
        internals->i_children = 0;
        vlc_object_destroy( p_this );
    }
}

/**
 ****************************************************************************
 * attach object to a parent object
 *****************************************************************************
 * This function sets p_this as a child of p_parent, and p_parent as a parent
 * of p_this. This link can be undone using vlc_object_detach.
 *****************************************************************************/
void __vlc_object_attach( vlc_object_t *p_this, vlc_object_t *p_parent )
{
    if( !p_this ) return;

    vlc_mutex_lock( &structure_lock );

    /* Attach the parent to its child */
    assert (!p_this->p_parent);
    p_this->p_parent = p_parent;

    /* Attach the child to its parent */
    vlc_object_internals_t *priv = vlc_internals( p_parent );
    INSERT_ELEM( priv->pp_children, priv->i_children, priv->i_children,
                 p_this );

    vlc_mutex_unlock( &structure_lock );
}


static void vlc_object_detach_unlocked (vlc_object_t *p_this)
{
    vlc_assert_locked (&structure_lock);

    if (p_this->p_parent == NULL)
        return;

    vlc_object_internals_t *priv = vlc_internals( p_this->p_parent );

    int i_index, i;

    /* Remove p_this's parent */
    p_this->p_parent = NULL;

    /* Remove all of p_parent's children which are p_this */
    for( i_index = priv->i_children ; i_index-- ; )
    {
        if( priv->pp_children[i_index] == p_this )
        {
            priv->i_children--;
            for( i = i_index ; i < priv->i_children ; i++ )
                priv->pp_children[i] = priv->pp_children[i+1];
        }
    }

    if( priv->i_children )
    {
        priv->pp_children = (vlc_object_t **)realloc( priv->pp_children,
                               priv->i_children * sizeof(vlc_object_t *) );
    }
    else
    {
        /* Special case - don't realloc() to zero to avoid leaking */
        free( priv->pp_children );
        priv->pp_children = NULL;
    }
}


/**
 ****************************************************************************
 * detach object from its parent
 *****************************************************************************
 * This function removes all links between an object and its parent.
 *****************************************************************************/
void __vlc_object_detach( vlc_object_t *p_this )
{
    if( !p_this ) return;

    vlc_mutex_lock( &structure_lock );
    if( !p_this->p_parent )
        msg_Err( p_this, "object is not attached" );
    else
        vlc_object_detach_unlocked( p_this );
    vlc_mutex_unlock( &structure_lock );
}


/**
 ****************************************************************************
 * find a list typed objects and increment their refcount
 *****************************************************************************
 * This function recursively looks for a given object type. i_mode can be one
 * of FIND_PARENT, FIND_CHILD or FIND_ANYWHERE.
 *****************************************************************************/
vlc_list_t * __vlc_list_find( vlc_object_t *p_this, int i_type, int i_mode )
{
    vlc_list_t *p_list;
    int i_count = 0;

    /* Look for the objects */
    switch( i_mode & 0x000f )
    {
    case FIND_ANYWHERE:
        /* Modules should probably not be object, and the module should perhaps
         * not be shared across LibVLC instances. In the mean time, this ugly
         * hack is brought to you by Courmisch. */
        if (i_type == VLC_OBJECT_MODULE)
            return vlc_list_find ((vlc_object_t *)vlc_global ()->p_module_bank,
                                  i_type, FIND_CHILD);
        return vlc_list_find (p_this->p_libvlc, i_type, FIND_CHILD);

    case FIND_CHILD:
        vlc_mutex_lock( &structure_lock );
        i_count = CountChildren( p_this, i_type );
        p_list = NewList( i_count );

        /* Check allocation was successful */
        if( p_list->i_count != i_count )
        {
            vlc_mutex_unlock( &structure_lock );
            msg_Err( p_this, "list allocation failed!" );
            p_list->i_count = 0;
            break;
        }

        p_list->i_count = 0;
        ListChildren( p_list, p_this, i_type );
        vlc_mutex_unlock( &structure_lock );
        break;

    default:
        msg_Err( p_this, "unimplemented!" );
        p_list = NewList( 0 );
        break;
    }

    return p_list;
}

/**
 * Gets the list of children of an objects, and increment their reference
 * count.
 * @return a list (possibly empty) or NULL in case of error.
 */
vlc_list_t *__vlc_list_children( vlc_object_t *obj )
{
    vlc_list_t *l;
    vlc_object_internals_t *priv = vlc_internals( obj );

    vlc_mutex_lock( &structure_lock );
    l = NewList( priv->i_children );
    for (int i = 0; i < l->i_count; i++)
    {
        vlc_object_yield( priv->pp_children[i] );
        l->p_values[i].p_object = priv->pp_children[i];
    }
    vlc_mutex_unlock( &structure_lock );
    return l;
}

/*****************************************************************************
 * DumpCommand: print the current vlc structure
 *****************************************************************************
 * This function prints either an ASCII tree showing the connections between
 * vlc objects, and additional information such as their refcount, thread ID,
 * etc. (command "tree"), or the same data as a simple list (command "list").
 *****************************************************************************/
static int DumpCommand( vlc_object_t *p_this, char const *psz_cmd,
                        vlc_value_t oldval, vlc_value_t newval, void *p_data )
{
    (void)oldval; (void)p_data;
    if( *psz_cmd == 'l' )
    {
        vlc_object_t *root = VLC_OBJECT (vlc_global ()), *cur = root; 

        vlc_mutex_lock( &structure_lock );
        do
        {
            PrintObject (cur, "");
            cur = vlc_internals (cur)->next;
        }
        while (cur != root);
        vlc_mutex_unlock( &structure_lock );
    }
    else
    {
        vlc_object_t *p_object = NULL;

        if( *newval.psz_string )
        {
            char *end;
            int i_id = strtol( newval.psz_string, &end, 0 );
            if( end != newval.psz_string )
                p_object = vlc_object_get( i_id );
            else
                /* try using the object's name to find it */
                p_object = vlc_object_find_name( p_this, newval.psz_string,
                                                 FIND_ANYWHERE );

            if( !p_object )
            {
                return VLC_ENOOBJ;
            }
        }

        vlc_mutex_lock( &structure_lock );

        if( *psz_cmd == 't' )
        {
            char psz_foo[2 * MAX_DUMPSTRUCTURE_DEPTH + 1];

            if( !p_object )
                p_object = p_this->p_libvlc ? VLC_OBJECT(p_this->p_libvlc) : p_this;

            psz_foo[0] = '|';
            DumpStructure( p_object, 0, psz_foo );
        }
        else if( *psz_cmd == 'v' )
        {
            int i;

            if( !p_object )
                p_object = p_this->p_libvlc ? VLC_OBJECT(p_this->p_libvlc) : p_this;

            PrintObject( p_object, "" );

            if( !vlc_internals( p_object )->i_vars )
                printf( " `-o No variables\n" );
            for( i = 0; i < vlc_internals( p_object )->i_vars; i++ )
            {
                variable_t *p_var = vlc_internals( p_object )->p_vars + i;

                const char *psz_type = "unknown";
                switch( p_var->i_type & VLC_VAR_TYPE )
                {
#define MYCASE( type, nice )                \
                    case VLC_VAR_ ## type:  \
                        psz_type = nice;    \
                        break;
                    MYCASE( VOID, "void" );
                    MYCASE( BOOL, "bool" );
                    MYCASE( INTEGER, "integer" );
                    MYCASE( HOTKEY, "hotkey" );
                    MYCASE( STRING, "string" );
                    MYCASE( MODULE, "module" );
                    MYCASE( FILE, "file" );
                    MYCASE( DIRECTORY, "directory" );
                    MYCASE( VARIABLE, "variable" );
                    MYCASE( FLOAT, "float" );
                    MYCASE( TIME, "time" );
                    MYCASE( ADDRESS, "address" );
                    MYCASE( MUTEX, "mutex" );
                    MYCASE( LIST, "list" );
#undef MYCASE
                }
                printf( " %c-o \"%s\" (%s",
                        i + 1 == vlc_internals( p_object )->i_vars ? '`' : '|',
                        p_var->psz_name, psz_type );
                if( p_var->psz_text )
                    printf( ", %s", p_var->psz_text );
                printf( ")" );
                if( p_var->i_type & VLC_VAR_ISCOMMAND )
                    printf( ", command" );
                if( p_var->i_entries )
                    printf( ", %d callbacks", p_var->i_entries );
                switch( p_var->i_type & 0x00f0 )
                {
                    case VLC_VAR_VOID:
                    case VLC_VAR_MUTEX:
                        break;
                    case VLC_VAR_BOOL:
                        printf( ": %s", p_var->val.b_bool ? "true" : "false" );
                        break;
                    case VLC_VAR_INTEGER:
                        printf( ": %d", p_var->val.i_int );
                        break;
                    case VLC_VAR_STRING:
                        printf( ": \"%s\"", p_var->val.psz_string );
                        break;
                    case VLC_VAR_FLOAT:
                        printf( ": %f", p_var->val.f_float );
                        break;
                    case VLC_VAR_TIME:
                        printf( ": %"PRIi64, (int64_t)p_var->val.i_time );
                        break;
                    case VLC_VAR_ADDRESS:
                        printf( ": %p", p_var->val.p_address );
                        break;
                    case VLC_VAR_LIST:
                        printf( ": TODO" );
                        break;
                }
                printf( "\n" );
            }
        }

        vlc_mutex_unlock( &structure_lock );

        if( *newval.psz_string )
        {
            vlc_object_release( p_object );
        }
    }

    return VLC_SUCCESS;
}

/*****************************************************************************
 * vlc_list_release: free a list previously allocated by vlc_list_find
 *****************************************************************************
 * This function decreases the refcount of all objects in the list and
 * frees the list.
 *****************************************************************************/
void vlc_list_release( vlc_list_t *p_list )
{
    int i_index;

    for( i_index = 0; i_index < p_list->i_count; i_index++ )
    {
        vlc_object_release( p_list->p_values[i_index].p_object );
    }

    free( p_list->p_values );
    free( p_list );
}

/*****************************************************************************
 * dump an object. (Debug function)
 *****************************************************************************/
void __vlc_object_dump( vlc_object_t *p_this )
{
    vlc_mutex_lock( &structure_lock );
    char psz_foo[2 * MAX_DUMPSTRUCTURE_DEPTH + 1];
    psz_foo[0] = '|';
    DumpStructure( p_this, 0, psz_foo );
    vlc_mutex_unlock( &structure_lock );
}

/* Following functions are local */

static vlc_object_t * FindObject( vlc_object_t *p_this, int i_type, int i_mode )
{
    int i;
    vlc_object_t *p_tmp;