Archipelago » blktap-utils

/*

 * Copyright (c) 2010, Citrix Systems, Inc.

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above copyright

 *       notice, this list of conditions and the following disclaimer in the

 *       documentation and/or other materials provided with the distribution.

 *     * Neither the name of XenSource Inc. nor the names of its contributors

 *       may be used to endorse or promote products derived from this software

 *       without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS 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 COPYRIGHT OWNER

 * OR 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.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <stdio.h>

#include <stdarg.h>

#include "tapdisk.h"

#include "tapdisk-stats.h"

#define BUG_ON(_cond) if (_cond) { td_panic(); }

static void

__stats_vsprintf(td_stats_t *st,

                      const char *fmt, va_list ap)

{

        size_t size = st->buf + st->size - st->pos;

        st->pos += vsnprintf(st->pos, size, fmt, ap);

}

static void __printf(2, 3)

__stats_sprintf(td_stats_t *st,

                     const char *fmt, ...)

{

        va_list ap;

        va_start(ap, fmt);

        __stats_vsprintf(st, fmt, ap);

        va_end(ap);

}

static void

__stats_enter(td_stats_t *st)

{

        st->depth++;

        BUG_ON(st->depth > TD_STATS_MAX_DEPTH);

        st->n_elem[st->depth] = 0;

}

static void

__stats_leave(td_stats_t *st)

{

        st->depth--;

}

static void

__stats_next(td_stats_t *st)

{

        int n_elem;

        n_elem = st->n_elem[st->depth];

        if (n_elem > 0)

                __stats_sprintf(st, ", ");

        st->n_elem[st->depth]++;

}

static void

__tapdisk_stats_enter(td_stats_t *st, char t)

{

        __stats_sprintf(st, "%c ", t);

        __stats_enter(st);

}

void

tapdisk_stats_enter(td_stats_t *st, char t)

{

        __stats_next(st);

        __tapdisk_stats_enter(st, t);

}

void

tapdisk_stats_leave(td_stats_t *st, char t)

{

        __stats_leave(st);

        __stats_sprintf(st, " %c", t);

}

static void

tapdisk_stats_vval(td_stats_t *st, const char *conv, va_list ap)

{

        char t = conv[0], fmt[32];

        __stats_next(st);

        switch (t) {

        case 's':

                __stats_vsprintf(st, "\"%s\"", ap);

                break;

        default:

                sprintf(fmt, "%%%s", conv);

                __stats_vsprintf(st, fmt, ap);

                break;

        }

}

void

tapdisk_stats_val(td_stats_t *st, const char *conv, ...)

{

        va_list ap;

        va_start(ap, conv);

        tapdisk_stats_vval(st, conv, ap);

        va_end(ap);

}

void

tapdisk_stats_field(td_stats_t *st, const char *key, const char *conv, ...)

{

        va_list ap;

        int n_elem;

        char t;

        n_elem = st->n_elem[st->depth]++;

        if (n_elem > 0)

                __stats_sprintf(st, ", ");

        __stats_sprintf(st, "\"%s\": ", key);

        if (!conv) {

                __stats_sprintf(st, "null");

                return;

        }

        t = conv[0];

        switch (t) {

        case '[':

        case '{':

                __tapdisk_stats_enter(st, t);

                break;

        default:

                va_start(ap, conv);

                __stats_enter(st);

                tapdisk_stats_vval(st, conv, ap);

                __stats_leave(st);

                va_end(ap);

        }

}