/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is libguac.
 *
 * The Initial Developer of the Original Code is
 * Michael Jumper.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * ***** END LICENSE BLOCK ***** */

#ifndef _GUAC_LAYER_H
#define _GUAC_LAYER_H

/**
 * Provides functions and structures required for allocating and using layers.
 *
 * @file layer.h
 */

typedef struct guac_layer guac_layer;

/**
 * Represents a single layer within the Guacamole protocol.
 */
struct guac_layer {

    /**
     * The index of this layer.
     */
    int index;

    /**
     * The URI which must be passed via a resource instruction to denote
     * a resource related to this layer. This value is automatically set
     * upon allocation.
     */
    char* uri;

    /**
     * The next allocated layer in the list of all layers.
     */
    guac_layer* __next;

    /**
     * The next available (unused) layer in the list of
     * allocated but free'd layers.
     */
    guac_layer* __next_available;

};

/**
 * Allocates a new buffer (invisible layer). An arbitrary index is
 * automatically assigned if no existing buffer is available for use.
 *
 * @param client The proxy client to allocate the buffer for.
 * @return The next available buffer, or a newly allocated buffer.
 */
guac_layer* guac_client_alloc_buffer(guac_client* client);

/**
 * Allocates a new layer. An arbitrary index is automatically assigned
 * if no existing layer is available for use.
 *
 * @param client The proxy client to allocate the layer buffer for.
 * @return The next available layer, or a newly allocated layer.
 */
guac_layer* guac_client_alloc_layer(guac_client* client);

/**
 * Returns the given buffer to the pool of available buffers, such that it
 * can be reused by any subsequent call to guac_client_allow_buffer().
 *
 * @param client The proxy client to return the buffer to.
 * @param layer The buffer to return to the pool of available buffers.
 */
void guac_client_free_buffer(guac_client* client, guac_layer* layer);

/**
 * Returns the given layer to the pool of available layers, such that it
 * can be reused by any subsequent call to guac_client_allow_layer().
 *
 * @param client The proxy client to return the layer to.
 * @param layer The buffer to return to the pool of available layer.
 */
void guac_client_free_layer(guac_client* client, guac_layer* layer);

#endif