/* err.c - error handling routines */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2002,2005,2007,2008  Free Software Foundation, Inc.
 *
 *  GRUB is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/err.h>
#include <grub/misc.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#define GRUB_ERROR_STACK_SIZE	10

grub_err_t grub_errno;
char grub_errmsg[GRUB_MAX_ERRMSG];
int grub_err_printed_errors;

static struct grub_error_saved grub_error_stack_items[GRUB_ERROR_STACK_SIZE];

static int grub_error_stack_pos;
static int grub_error_stack_assert;

grub_err_t
grub_error(grub_err_t n, const char* fmt, ...)
{
	va_list ap;

	grub_errno = n;

	va_start(ap, fmt);
	vsnprintf(grub_errmsg, sizeof(grub_errmsg), fmt, ap);
	va_end(ap);

	return n;
}

void
grub_error_push(void)
{
	/* Only add items to stack, if there is enough room.  */
	if (grub_error_stack_pos < GRUB_ERROR_STACK_SIZE)
	{
		/* Copy active error message to stack.  */
		grub_error_stack_items[grub_error_stack_pos].grub_errno = grub_errno;
		memcpy(grub_error_stack_items[grub_error_stack_pos].errmsg,
			grub_errmsg,
			sizeof(grub_errmsg));

		/* Advance to next error stack position.  */
		grub_error_stack_pos++;
	}
	else
	{
		/* There is no room for new error message. Discard new error message
			 and mark error stack assertion flag.  */
		grub_error_stack_assert = 1;
	}

	/* Allow further operation of other components by resetting
		 active errno to GRUB_ERR_NONE.  */
	grub_errno = GRUB_ERR_NONE;
}

int
grub_error_pop(void)
{
	if (grub_error_stack_pos > 0)
	{
		/* Pop error message from error stack to current active error.  */
		grub_error_stack_pos--;

		grub_errno = grub_error_stack_items[grub_error_stack_pos].grub_errno;
		memcpy(grub_errmsg,
			grub_error_stack_items[grub_error_stack_pos].errmsg,
			sizeof(grub_errmsg));

		return 1;
	}
	else
	{
		/* There is no more items on error stack, reset to no error state.  */
		grub_errno = GRUB_ERR_NONE;

		return 0;
	}
}

void
grub_print_error(void)
{
	/* Print error messages in reverse order. First print active error message
		 and then empty error stack.  */
	do
	{
		if (grub_errno != GRUB_ERR_NONE)
		{
			grub_err_printf("error: %s.\n", grub_errmsg);
			grub_err_printed_errors++;
		}
	} while (grub_error_pop());

	/* If there was an assert while using error stack, report about it.  */
	if (grub_error_stack_assert)
	{
		grub_err_printf("assert: error stack overflow detected!\n");
		grub_error_stack_assert = 0;
	}
}
