1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/io/tx_layer.c	Sat Feb 20 21:18:28 2010 -0800
     1.3 @@ -0,0 +1,150 @@
     1.4 +/*
     1.5 + * $Id: tx_layer.c,v 1.7 2004/03/24 06:37:30 hipnod Exp $
     1.6 + *
     1.7 + * Copyright (C) 2003 giFT project (gift.sourceforge.net)
     1.8 + *
     1.9 + * This program is free software; you can redistribute it and/or modify it
    1.10 + * under the terms of the GNU General Public License as published by the
    1.11 + * Free Software Foundation; either version 2, or (at your option) any
    1.12 + * later version.
    1.13 + *
    1.14 + * This program is distributed in the hope that it will be useful, but
    1.15 + * WITHOUT ANY WARRANTY; without even the implied warranty of
    1.16 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    1.17 + * General Public License for more details.
    1.18 + */
    1.19 +
    1.20 +#include "gt_gnutella.h"
    1.21 +
    1.22 +#include "io/tx_stack.h"
    1.23 +#include "io/tx_layer.h"
    1.24 +#include "io/io_buf.h"
    1.25 +
    1.26 +/*****************************************************************************/
    1.27 +
    1.28 +struct tx_layer *gt_tx_layer_new (GtTxStack *stack, const char *name,
    1.29 +                                  struct tx_layer_ops *ops)
    1.30 +{
    1.31 +	struct tx_layer *tx;
    1.32 +
    1.33 +	if (!(tx = NEW (struct tx_layer)))
    1.34 +		return NULL;
    1.35 +
    1.36 +	tx->ops         = ops;
    1.37 +	tx->name        = name;
    1.38 +	tx->stack       = stack;
    1.39 +	tx->partial_buf = NULL;
    1.40 +
    1.41 +	if (!ops->init (tx))
    1.42 +	{
    1.43 +		free (tx);
    1.44 +		return NULL;
    1.45 +	}
    1.46 +
    1.47 +	return tx;
    1.48 +}
    1.49 +
    1.50 +void gt_tx_layer_free (struct tx_layer *layer)
    1.51 +{
    1.52 +	if (!layer)
    1.53 +		return;
    1.54 +
    1.55 +	io_buf_free (layer->partial_buf);
    1.56 +
    1.57 +	layer->ops->destroy (layer);
    1.58 +
    1.59 +	FREE (layer);
    1.60 +}
    1.61 +
    1.62 +/*****************************************************************************/
    1.63 +
    1.64 +static tx_status_t queue_data (struct tx_layer *tx, struct io_buf *io_buf)
    1.65 +{
    1.66 +	tx_status_t ret;
    1.67 +
    1.68 +	ret = tx->ops->queue (tx, io_buf);
    1.69 +
    1.70 +	/*
    1.71 +	 * If the message didn't get completely written, buffer the partial
    1.72 +	 * message buffer until it's finished.
    1.73 +	 */
    1.74 +	if (ret == TX_PARTIAL)
    1.75 +	{
    1.76 +		assert (io_buf_read_avail (io_buf) > 0);
    1.77 +
    1.78 +		tx->partial_buf = io_buf;
    1.79 +		return TX_OK;
    1.80 +	}
    1.81 +
    1.82 +	return ret;
    1.83 +}
    1.84 +
    1.85 +/* send a message to the layer underneath this one */
    1.86 +tx_status_t gt_tx_layer_queue (struct tx_layer *tx, struct io_buf *io_buf)
    1.87 +{
    1.88 +	struct tx_layer *lower = tx->lower;
    1.89 +
    1.90 +	if (lower->partial_buf)
    1.91 +		return TX_FULL;
    1.92 +
    1.93 +	return queue_data (lower, io_buf);
    1.94 +}
    1.95 +
    1.96 +/* let upper layer know we're writable and get data from it */
    1.97 +tx_status_t gt_tx_layer_ready (struct tx_layer *tx)
    1.98 +{
    1.99 +	struct tx_layer *upper;
   1.100 +	tx_status_t      ret;
   1.101 +
   1.102 +	upper = tx->upper;
   1.103 +
   1.104 +	/*
   1.105 +	 * If there is a partially written buffer on the layer, try to finish it
   1.106 +	 * off before asking for more data by pretending the upper layer tried to
   1.107 +	 * write it.
   1.108 +	 *
   1.109 +	 * Doing this avoids a special case in each layer where a partial buffer
   1.110 +	 * is kept set aside and checked before calling gt_tx_layer_ready(), leading
   1.111 +	 * to less code.
   1.112 +	 */
   1.113 +	if (tx->partial_buf)
   1.114 +	{
   1.115 +		struct io_buf *io_buf = tx->partial_buf;
   1.116 +
   1.117 +		tx->partial_buf = NULL;
   1.118 +
   1.119 +		/* this ends up calling this layer's queue func */
   1.120 +		ret = queue_data (tx, io_buf);
   1.121 +
   1.122 +		/*
   1.123 +		 * Can't happen because layer wouldn't have invoked us.
   1.124 +		 */
   1.125 +		assert (ret != TX_FULL);
   1.126 +		assert (ret != TX_EMPTY);
   1.127 +
   1.128 +		/*
   1.129 +		 * Upper layer can't be safely invoked again, even if the partial
   1.130 +		 * buffer was completed, because we don't know if the lower layer has
   1.131 +		 * any more room.  So, the lower layer must reinvoke tx_layer_ready()
   1.132 +		 * to write more data.
   1.133 +		 */
   1.134 +		return ret;
   1.135 +	}
   1.136 +
   1.137 +	ret = upper->ops->ready (upper);
   1.138 +	assert (ret != TX_FULL);
   1.139 +
   1.140 +	return ret;
   1.141 +}
   1.142 +
   1.143 +/*****************************************************************************/
   1.144 +
   1.145 +void gt_tx_layer_enable (struct tx_layer *layer)
   1.146 +{
   1.147 +	layer->ops->enable (layer);
   1.148 +}
   1.149 +
   1.150 +void gt_tx_layer_disable (struct tx_layer *layer)
   1.151 +{
   1.152 +	layer->ops->disable (layer);
   1.153 +}