/*
 * Copyright (C) 2011-2012  J. Ali Harlow <ali@juiblex.co.uk>
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <assert.h>

#include "razor.h"
#include "razor-internal.h"

/*
 * Atomic transactions
 */

static int allow_all_root_names = 0;

/*
 * Primarily intended for testing named roots under UNIX platforms.
 */
RAZOR_EXPORT void
razor_disable_root_name_checks(int disable)
{
	allow_all_root_names = disable;
}

int
razor_allow_all_root_names(void)
{
	return allow_all_root_names;
}

RAZOR_EXPORT const char *
razor_atomic_get_error_msg(struct razor_atomic *atomic)
{
	if (!atomic->error_msg) {
		if (atomic->error_path)
			atomic->error_msg = razor_concat(atomic->error_path,
							 ": ",
							 atomic->error_str,
							 NULL);
		else
			atomic->error_msg = strdup(atomic->error_str);
	}

	return atomic->error_msg;
}

RAZOR_EXPORT void
razor_atomic_abort(struct razor_atomic *atomic, const char *error_msg)
{
	if (!atomic->error_str)
		razor_atomic_set_error_str(atomic, NULL, error_msg);
}

RAZOR_EXPORT int
razor_atomic_in_error_state(struct razor_atomic *atomic)
{
	return atomic->error_str && !atomic->in_undo;
}

#if !HAVE_WINDOWS_KTM

/*
 * Common code with atomic-none and atomic-emulate
 */

#define RAZOR_ASCII_ISALPHA(c)	\
			((c) >= 'A' && (c) <= 'Z' || (c) >= 'a' && (c) <= 'z')

int
razor_valid_root_name(const char *name)
{
	if (razor_allow_all_root_names()) {
#ifdef MSWIN_API
		return !strpbrk(name, "/\\");
#else
		return !strchr(name, '/');
#endif
	}

#ifdef MSWIN_API
	return RAZOR_ASCII_ISALPHA(name[0]) && name[1] == ':' &&
	       name[2] == '\0';
#else
	return name[0] == '\0';
#endif
}

#ifdef MSWIN_API
void
razor_atomic_set_error_mswin(struct razor_atomic *atomic, const wchar_t *path,
			     DWORD error)
{
	wchar_t *buf;

	assert(!atomic->error_str);

	free(atomic->error_path);

	if (path)
		atomic->error_path = razor_utf16_to_utf8(path, -1);
	else
		atomic->error_path = NULL;

	FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER|
		       FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
		       NULL, error, MAKELANGID(LANG_NEUTRAL,SUBLANG_DEFAULT),
		       (LPWSTR)&buf, 0, NULL);
	atomic->error_str = razor_utf16_to_utf8(buf, -1);
	LocalFree(buf);
}
#endif

void
razor_atomic_set_error_str(struct razor_atomic *atomic, const char *path,
			   const char *str)
{
	assert(!atomic->error_str);

	atomic->error_path = path ? strdup(path) : NULL;
	atomic->error_str = strdup(str);
}

RAZOR_EXPORT int
razor_atomic_write(struct razor_atomic *atomic, int fd, const void *data,
		   size_t size)
{
	int written;

	if (razor_atomic_in_error_state(atomic))
		return -1;

	while(size) {
		written = write(fd, data, size);
		if (written < 0) {
			razor_atomic_set_error_str(atomic, NULL,
						   strerror(errno));

			(void)close(fd);

			return -1;
		}

		data += written;
		size -= written;
	}

	return 0;
}

RAZOR_EXPORT int
razor_atomic_sync(struct razor_atomic *atomic, int handle)
{
	if (razor_atomic_in_error_state(atomic))
		return -1;

	if (fsync(handle) < 0) {
		razor_atomic_set_error_str(atomic, NULL, strerror(errno));
		return -1;
	}

	free(atomic->error_path);
	atomic->error_path = NULL;

	return 0;
}

RAZOR_EXPORT int
razor_atomic_close(struct razor_atomic *atomic, int fd)
{
	if (razor_atomic_in_error_state(atomic))
		return -1;

	if (close(fd) < 0) {
		razor_atomic_set_error_str(atomic, NULL, strerror(errno));
		return -1;
	}

	free(atomic->error_path);
	atomic->error_path = NULL;

	return 0;
}

#endif	/* !HAVE_WINDOWS_KTM */