ossp-pkg/l2/l2_channel.c
1.20
/*
** L2 - OSSP Logging Library
** Copyright (c) 2001 The OSSP Project (http://www.ossp.org/)
** Copyright (c) 2001 Cable & Wireless Deutschland (http://www.cw.com/de/)
**
** This file is part of OSSP L2, a flexible logging library which
** can be found at http://www.ossp.org/pkg/l2/.
**
** Permission to use, copy, modify, and distribute this software for
** any purpose with or without fee is hereby granted, provided that
** the above copyright notice and this permission notice appear in all
** copies.
**
** THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
** CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
** USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
** ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
** OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
** OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
** SUCH DAMAGE.
**
** l2_channel.c: channel handling
**
*/
#include "l2.h"
#include "l2_p.h"
#include <string.h>
/*
* A channel is the central object for a logging stream. It is
* implemented by a framework (the code implemented here) which provides
* the channel API and which is equal for all channels and a particular
* handler which implements the characteristics specific to a particular
* channel class. The lifecycle of a channel is illustrated in the
* following figure:
*
* -----BEGIN EMBEDDED OBJECT-----
* Content-editor: xfig %s
* Content-encoding: gzip:9 base64
* Content-type: application/fig
* Content-viewer: xfig %s
* Description: L2 Channel Lifecycle
* Filename: l2_ch_lifecycle.fig
* Last-modified: 2000-09-28/14:40
* Name: l2_ch_lifecycle
* Version: eo/1.0
* H4sIAIsvszsCA62WTW/bMAyGz/WvENBzM5KyPnwusGFAdtp1l8BVWgOZUyTuhv77
* kfKHnC4t5CZJ7JAO3kcUKUq5/fr9m9IrKtab9uFYb55DcR/aLhyKH6E7NHWxDh17
* ShUIsAIofjbt4y4Ud1QgASgqQGlSt3V8Fai0AoV8gTJyI76xLD6Tb35iPSpybNlS
* PsknV5po5WC0BZZRWSlL8km+tlYsa3MwJfAP6Kdokl8iltHKwjiwJ5jJL52DbIxB
* Z+aY5BvSVT7GEieSzISZfGN9Fa0cjAVj55iZz7XPxxg6mdTMNz5/Ug55ncwwyXdU
* mnyMPS148p1bUHCPAPPcJN+jLOrM3GjUOMckX2PV16ygiJDL9Zi7Qa4GR36i4kYM
* XMW6yZ1LJP160y+iofqUy4SeKW01zCtaMT2XBjSRUrdFJr1h0rmAZg3qhnV0cUAT
* KTVcfoYsjOmN1jLxbPWJdZV6T2GkTstPb2pOh3ilek+kNN3LmWO6UuflZB0/YvYk
* B+eYXpi4PM4YYs80g3XK/Gh1JHG0UC/p3OFIhRkhiuXNJ3aaDr0/tKExbraWqtFX
* g1qsiyue8qDxWq0ykdI+l5/g2eE87rCX79XGj8cK6CGgMh0gyH8qYPrPoTCeGzx0
* Jft6yUHU+3bbPL4cwi8AzFAazU+XKXlJlHL6O64uec3KQ9h0OQPK1uJRZNob9RCO
* 3WH/mjGc5kC1HXX759Bmiixas0jkZHIgBy9wrH8PTRe+bHcvx6dMrTUOPqOVYA1x
* sFhJQnf7Y8hUOVfCOZV/v3h+3N88W7tmG7rm9ztCXPGE/Gw4IuAgLUd67M4V3f8/
* nPS/M9IprN/UXfMnR2b8MA4Rl6Np3wh9EtJM6OWRlkGrfrtUa1L3T5u2DTu15qnW
* r/Wup/wDvlAM/PkMAAA=
* -----END EMBEDDED OBJECT-----
*/
/* create channel */
l2_channel_t *l2_channel_create(l2_handler_t *h)
{
l2_channel_t *ch;
/* argument sanity check */
if (h == NULL)
return NULL;
/* allocate channel structure */
if ((ch = (l2_channel_t *)malloc(sizeof(l2_channel_t))) == NULL)
return NULL;
/* initialize channel structure */
ch->state = L2_CHSTATE_CREATED;
ch->downstream = NULL;
memset(&ch->context, 0, sizeof(l2_context_t));
memcpy(&ch->handler, h, sizeof(l2_handler_t));
ch->rvErrorInfo = L2_OK;
ch->szErrorInfo[0] = '\0';
ch->szError[0] = '\0';
/* (optionally) perform create operation in handler */
if (ch->handler.create != NULL) {
if (ch->handler.create(&ch->context, ch) != L2_OK) {
free(ch);
return NULL;
}
}
return ch;
}
/* configure channel */
l2_result_t l2_channel_configure(l2_channel_t *ch, const char *fmt, ...)
{
l2_result_t rv;
va_list ap;
/* argument sanity check */
if (ch == NULL || fmt == NULL)
return L2_ERR_ARG;
/* make sure the channel is in state "created" */
if (ch->state != L2_CHSTATE_CREATED)
return L2_ERR_USE;
/* pass operation to handler */
rv = L2_OK;
va_start(ap, fmt);
if (ch->handler.configure != NULL)
rv = ch->handler.configure(&ch->context, ch, fmt, ap);
va_end(ap);
return rv;
}
/* open channel (stack) */
l2_result_t l2_channel_open(l2_channel_t *ch)
{
l2_result_t rv;
/* argument sanity check */
if (ch == NULL)
return L2_ERR_ARG;
/* make sure channel is in state "created" */
if (ch->state != L2_CHSTATE_CREATED)
return L2_ERR_USE;
/* skip empty open handlers on channel stack */
while (ch != NULL && ch->handler.open == NULL) {
ch->state = L2_CHSTATE_OPENED;
ch = ch->downstream;
}
if (ch == NULL)
return L2_ERR_USE;
/* pass operation to handler */
rv = ch->handler.open(&ch->context, ch);
if (rv == L2_OK)
ch->state = L2_CHSTATE_OPENED;
return rv;
}
/* write to channel (stack) */
l2_result_t l2_channel_write(l2_channel_t *ch, l2_level_t level, const char *buf, size_t bufsize)
{
l2_result_t rv;
/* argument sanity check */
if (ch == NULL || buf == NULL)
return L2_ERR_ARG;
/* make sure channel is in state "opened" */
if (ch->state != L2_CHSTATE_OPENED)
return L2_ERR_USE;
/* short circuiting */
if (bufsize == 0)
return L2_OK;
/* walk to next available write handler */
while (ch != NULL && ch->handler.write == NULL)
ch = ch->downstream;
if (ch == NULL)
return L2_ERR_USE;
/* pass operation to handler */
rv = ch->handler.write(&ch->context, ch, level, buf, bufsize);
return rv;
}
/* flush channel (stack) */
l2_result_t l2_channel_flush(l2_channel_t *ch)
{
l2_result_t rv;
/* argument sanity check */
if (ch == NULL)
return L2_ERR_ARG;
/* make sure channel is in state "opened" */
if (ch->state != L2_CHSTATE_OPENED)
return L2_ERR_USE;
/* walk to next available flush handler */
while (ch != NULL && ch->handler.flush == NULL)
ch = ch->downstream;
if (ch == NULL)
return L2_ERR_USE;
/* pass operation to handler */
rv = ch->handler.flush(&ch->context, ch);
return rv;
}
/* close channel (stack) */
l2_result_t l2_channel_close(l2_channel_t *ch)
{
l2_result_t rv;
/* argument sanity check */
if (ch == NULL)
return L2_ERR_ARG;
/* make sure channel is in state "opened" */
if (ch->state != L2_CHSTATE_OPENED)
return L2_ERR_USE;
/* walk to next available close handler */
while (ch != NULL && ch->handler.close == NULL) {
ch->state = L2_CHSTATE_CREATED;
ch = ch->downstream;
}
if (ch == NULL)
return L2_ERR_USE;
/* pass operation to handler */
rv = ch->handler.close(&ch->context, ch);
if (rv == L2_OK)
ch->state = L2_CHSTATE_CREATED;
return rv;
}
/* destroy channel */
l2_result_t l2_channel_destroy(l2_channel_t *ch)
{
l2_result_t rv;
/* argument sanity check */
if (ch == NULL)
return L2_ERR_ARG;
/* make sure channel is in state "opened" */
if (ch->state == L2_CHSTATE_OPENED)
if ((rv = l2_channel_close(ch)) != L2_OK)
return rv;
/* walk to next available destroy handler */
while (ch != NULL && ch->handler.destroy == NULL)
ch = ch->downstream;
/* pass operation to handler */
if (ch != NULL)
rv = ch->handler.destroy(&ch->context, ch);
else
rv = L2_OK;
/* free channel structure */
free(ch);
return rv;
}
l2_result_t l2_channel_errorinfo(l2_channel_t *ch, l2_result_t rv, const char *fmt, ...)
{
va_list ap;
/* argument sanity check */
if (ch == NULL || rv == L2_OK || fmt == NULL)
return L2_ERR_ARG;
/* remember error information */
va_start(ap, fmt);
l2_util_vsprintf(ch->szErrorInfo, sizeof(ch->szErrorInfo), fmt, ap);
ch->rvErrorInfo = rv;
va_end(ap);
return L2_OK;
}
char *l2_channel_strerror(l2_channel_t *ch, l2_result_t rv)
{
char *sz;
char *cpBuf;
int nBuf;
int n;
/* argument sanity check */
if (ch == NULL)
return NULL;
/* start at begin of buffer */
cpBuf = ch->szError;
nBuf = sizeof(ch->szError);
/* translate result value into corresponding string */
if (rv == L2_OK) sz = "everything ok";
else if (rv == L2_ERR_ARG) sz = "invalid argument";
else if (rv == L2_ERR_USE) sz = "invalid use";
else if (rv == L2_ERR_MEM) sz = "no more memory available";
else if (rv == L2_ERR_SYS) sz = "operating system error";
else if (rv == L2_ERR_IO) sz = "input/output error";
else if (rv == L2_ERR_FMT) sz = "formatting error";
else if (rv == L2_ERR_INT) sz = "internal error";
else sz = "unknown error";
n = l2_util_sprintf(cpBuf, nBuf, "%s", sz);
cpBuf += n;
nBuf -= n;
/* optionally annotate with error information */
if (rv == ch->rvErrorInfo && ch->szErrorInfo[0] != '\0') {
n = l2_util_sprintf(cpBuf, nBuf, "; %s", ch->szErrorInfo);
cpBuf += n;
nBuf -= n;
}
/* optionally annotate with operating system error information */
if (rv == L2_ERR_SYS) {
n = l2_util_sprintf(cpBuf, nBuf, "; %s (%d)", strerror(errno), errno);
cpBuf += n;
nBuf -= n;
}
/* return pointer to internal buffer */
return ch->szError;
}
/* stack channel on top of another channel */
l2_result_t l2_channel_stack(l2_channel_t *ch, l2_channel_t *chTop)
{
/* argument sanity check */
if (ch == NULL || chTop == NULL)
return L2_ERR_ARG;
/* make sure both channels are in state "created" */
if ( ch->state != L2_CHSTATE_CREATED
|| chTop->state != L2_CHSTATE_CREATED)
return L2_ERR_USE;
/* make sure top channel is a filter channel */
if (chTop->handler.type != L2_CHANNEL_FILTER)
return L2_ERR_USE;
/* stack the channels */
chTop->downstream = ch;
return L2_OK;
}
/* return downstream channel */
l2_channel_t *l2_channel_downstream(l2_channel_t *ch)
{
/* argument sanity check */
if (ch == NULL)
return NULL;
return ch->downstream;
}
/* return channel type */
l2_chtype_t l2_channel_type(l2_channel_t *ch)
{
/* argument sanity check */
if (ch == NULL)
return L2_CHANNEL_FILTER; /* FIXME */
return ch->handler.type;
}
