/*-
 * Copyright (c) 2014-2016 MongoDB, Inc.
 * Copyright (c) 2008-2014 WiredTiger, Inc.
 *	All rights reserved.
 *
 * See the file LICENSE for redistribution information.
 */

#include "wt_internal.h"

/*
 * __wt_errno --
 *	Return errno, or WT_ERROR if errno not set.
 */
int
__wt_errno(void)
{
	/*
	 * Called when we know an error occurred, and we want the system
	 * error code, but there's some chance it's not set.
	 */
	return (errno == 0 ? WT_ERROR : errno);
}

/*
 * __wt_strerror --
 *	WT_SESSION.strerror and wiredtiger_strerror.
 */
const char *
__wt_strerror(WT_SESSION_IMPL *session, int error, char *errbuf, size_t errlen)
{
	const char *p;

	/*
	 * Check for a WiredTiger or POSIX constant string, no buffer needed.
	 */
	if ((p = __wt_wiredtiger_error(error)) != NULL)
		return (p);

	/*
	 * When called from wiredtiger_strerror, write a passed-in buffer.
	 * When called from WT_SESSION.strerror, write the session's buffer.
	 *
	 * Fallback to a generic message.
	 */
	if (session == NULL &&
	    __wt_snprintf(errbuf, errlen, "error return: %d", error) == 0)
		return (errbuf);
	if (session != NULL && __wt_buf_fmt(
	    session, &session->err, "error return: %d", error) == 0)
		return (session->err.data);

	/* Defeated. */
	return ("Unable to return error string");
}

/*
 * __wt_ext_map_windows_error --
 *	Extension API call to map a Windows system error to a POSIX/ANSI error.
 */
int
__wt_ext_map_windows_error(
    WT_EXTENSION_API *wt_api, WT_SESSION *wt_session, uint32_t windows_error)
{
	WT_UNUSED(wt_api);
	WT_UNUSED(wt_session);

	/*
	 * This extension API only makes sense in Windows builds, but it's hard
	 * to exclude it otherwise (there's no way to return an error, anyway).
	 * Call an underlying function on Windows, else panic so callers figure
	 * out what they're doing wrong.
	 */
#ifdef _WIN32
	return (__wt_map_windows_error(windows_error));
#else
	WT_UNUSED(windows_error);
	return (WT_PANIC);
#endif
}
