/*****************************************************************************
 * RRDtool 1.2.23  Copyright by Tobi Oetiker, 1997-2007
 * This file:     Copyright 2003 Peter Stamfest <peter@stamfest.at> 
 *                             & Tobias Oetiker
 * Distributed under the GPL
 *****************************************************************************
 * rrd_thread_safe.c   Contains routines used when thread safety is required
 *****************************************************************************
 * $Id: rrd_thread_safe.c 1050 2007-05-02 18:06:05Z oetiker $
 *************************************************************************** */

#include <pthread.h>
#include <string.h>
/* #include <error.h> */
#include "rrd.h"
#include "rrd_tool.h"

/* Key for the thread-specific rrd_context */
static pthread_key_t context_key;

/* Once-only initialisation of the key */
static pthread_once_t context_key_once = PTHREAD_ONCE_INIT;

/* Free the thread-specific rrd_context - we might actually use
   rrd_free_context instead...
 */
static void context_destroy_context(void *ctx_)
{
    struct rrd_context *ctx = ctx_;
    if (ctx) rrd_free_context(ctx);
}

/* Allocate the key */
static void context_get_key()
{
    pthread_key_create(&context_key, context_destroy_context);
}

struct rrd_context *rrd_get_context(void) {
    struct rrd_context *ctx;

    pthread_once(&context_key_once, context_get_key);
    ctx = pthread_getspecific(context_key);
    if (!ctx) {
	ctx = rrd_new_context();
	pthread_setspecific(context_key, ctx);
    } 
    return ctx;
}

#ifdef HAVE_STRERROR_R
const char *rrd_strerror(int err) {
    struct rrd_context *ctx = rrd_get_context();
    if (strerror_r(err, ctx->lib_errstr, ctx->errlen)) 
         return "strerror_r faild. sorry!"; 
    else 
         return ctx->lib_errstr; 
}
#else
#undef strerror
const char *rrd_strerror(int err) {
    static pthread_mutex_t mtx = PTHREAD_MUTEX_INITIALIZER;
    struct rrd_context *ctx;
    ctx = rrd_get_context();
    pthread_mutex_lock(&mtx);
    strncpy(ctx->lib_errstr, strerror(err), ctx->errlen);
    ctx->lib_errstr[ctx->errlen]='\0';
    pthread_mutex_unlock(&mtx);
    return ctx->lib_errstr;
}
#endif