lang/c/src/errors.c

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.  See the License for the specific language governing
 * permissions and limitations under the License.
 */

#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include "avro/errors.h"

#if defined THREADSAFE && (defined __unix__ || defined __unix)
#include <pthread.h>
static pthread_key_t error_data_key;
static pthread_once_t error_data_key_once = PTHREAD_ONCE_INIT;

static void make_error_data_key()
{
    pthread_key_create(&error_data_key, free);
}
#endif

/* 4K should be enough, right? */
#define AVRO_ERROR_SIZE 4096

/*
 * To support the avro_prefix_error function, we keep two string buffers
 * around.  The AVRO_CURRENT_ERROR points at the buffer that's holding
 * the current error message.  avro_prefix error writes into the other
 * buffer, and then swaps them.
 */

struct avro_error_data_t {
    char  AVRO_ERROR1[AVRO_ERROR_SIZE];
    char  AVRO_ERROR2[AVRO_ERROR_SIZE];

    char  *AVRO_CURRENT_ERROR;
    char  *AVRO_OTHER_ERROR;
};


static struct avro_error_data_t *
avro_get_error_data(void)
{
#if defined THREADSAFE && (defined __unix__ || defined __unix)
    pthread_once(&error_data_key_once, make_error_data_key);

    struct avro_error_data_t *ERROR_DATA =
        (struct avro_error_data_t*) pthread_getspecific(error_data_key);

    if (!ERROR_DATA) {
        ERROR_DATA = (struct avro_error_data_t*) malloc(sizeof(struct avro_error_data_t));
        pthread_setspecific(error_data_key, ERROR_DATA);

        ERROR_DATA->AVRO_ERROR1[0] = '\0';
        ERROR_DATA->AVRO_ERROR2[0] = '\0';
        ERROR_DATA->AVRO_CURRENT_ERROR = ERROR_DATA->AVRO_ERROR1;
        ERROR_DATA->AVRO_OTHER_ERROR = ERROR_DATA->AVRO_ERROR2;
    }

    return ERROR_DATA;
#else
    static struct avro_error_data_t ERROR_DATA = {
      /* .AVRO_ERROR1 = */ {'\0'},
      /* .AVRO_ERROR2 = */ {'\0'},
      /* .AVRO_CURRENT_ERROR = */ ERROR_DATA.AVRO_ERROR1,
      /* .AVRO_OTHER_ERROR = */ ERROR_DATA.AVRO_ERROR2,
    };

    return &ERROR_DATA;
#endif
}


void
avro_set_error(const char *fmt, ...)
{
	va_list  args;
	va_start(args, fmt);
	vsnprintf(avro_get_error_data()->AVRO_CURRENT_ERROR, AVRO_ERROR_SIZE, fmt, args);
	va_end(args);
	//fprintf(stderr, "--- %s\n", AVRO_CURRENT_ERROR);
}


void
avro_prefix_error(const char *fmt, ...)
{
    struct avro_error_data_t *ERROR_DATA = avro_get_error_data();

	/*
	 * First render the prefix into OTHER_ERROR.
	 */

	va_list  args;
	va_start(args, fmt);
	int  bytes_written = vsnprintf(ERROR_DATA->AVRO_OTHER_ERROR, AVRO_ERROR_SIZE, fmt, args);
	va_end(args);

	/*
	 * Then concatenate the existing error onto the end.
	 */

	if (bytes_written < AVRO_ERROR_SIZE) {
		strncpy(&ERROR_DATA->AVRO_OTHER_ERROR[bytes_written], ERROR_DATA->AVRO_CURRENT_ERROR,
			AVRO_ERROR_SIZE - bytes_written);
		ERROR_DATA->AVRO_OTHER_ERROR[AVRO_ERROR_SIZE-1] = '\0';
	}

	/*
	 * Swap the two error pointers.
	 */

	char  *tmp;
	tmp = ERROR_DATA->AVRO_OTHER_ERROR;
	ERROR_DATA->AVRO_OTHER_ERROR = ERROR_DATA->AVRO_CURRENT_ERROR;
	ERROR_DATA->AVRO_CURRENT_ERROR = tmp;
	//fprintf(stderr, "+++ %s\n", AVRO_CURRENT_ERROR);
}


const char *avro_strerror(void)
{
	return avro_get_error_data()->AVRO_CURRENT_ERROR;
}