/*
 *	aegis - project change supervisor
 *	Copyright (C) 1999 Peter Miller;
 *	All rights reserved.
 *
 *	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., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * MANIFEST: functions to manipulate sames
 */

#include <change/file.h>
#include <error.h>
#include <os.h>
#include <trace.h>


/*
 * NAME
 *	change_fingerprint_same
 *
 * SYNOPSIS
 *	int change_fingerprint_same(fingerprint fp, string_ty *path);
 *
 * DESCRIPTION
 *	The change_fingerprint_same function is used to test if a file
 *	fingerprint is the same.  This implies the file itself is the
 *	same.  If the file does not exist, it is aas if the fingerprint
 *	hash changed.
 *
 * RETURNS
 *	int;	1 -> the file is the SAME
 *		0 -> the file has changed
 */

int
change_fingerprint_same(fp, path, check_always)
	fingerprint	fp;
	string_ty	*path;
	int		check_always;
{
	time_t		oldest;
	time_t		newest;
	string_ty	*crypto;

	/*
	 * a NULL pointer means something very weird is going on
	 */
	trace(("change_fingerprint_same(fp = %8.8lX, path = \"%s\")\n{\n"/*}*/, (long)fp, path->str_text));
	if (!fp)
	{
		trace(("No existing fingerprint\n"));
		trace(("return 0;\n"));
		trace((/*{*/"}\n"));
		return 0;
	}
	assert(fp->youngest >= 0);
	assert(fp->oldest >= 0);

	/*
	 * If the file does not exist, clear the fingerprint and say
	 * that the file "is not the same".
	 */
	if (!os_exists(path))
	{
		fp->youngest = 0;
		fp->oldest = 0;
		if (fp->crypto)
		{
			str_free(fp->crypto);
			fp->crypto = 0;
		}
		trace(("no file there to fingerprint\n"));
		trace(("return 0;\n"));
		trace((/*{*/"}\n"));
		return 0;
	}

	/*
	 * The youngest field and the file's mtime should be the same;
	 * if it is, don't bother checking the fingerprint, just say the
	 * the file is the same.  (The os_mtime function checks the
	 * ctime, too, just in case the user is trying to fake us out.)
	 */
	os_mtime_range(path, &oldest, &newest);
	assert(oldest > 0);
	assert(newest > 0);
	if
	(
		!check_always
	&&
		fp->crypto
	&&
		fp->oldest
	&&
		fp->youngest
	&&
		fp->youngest == newest
	)
	{
		trace(("file times match\n"));
		if (oldest < fp->oldest)
			fp->oldest = oldest;
		trace(("return 1;\n"));
		trace((/*{*/"}\n"));
		return 1;
	}

	/*
	 * Read the fingerprint.  If it is the same as before,
	 * extend the valid time range, and say the file is the same.
	 */
	crypto = os_fingerprint(path);
	if
	(
		fp->crypto
	&&
		fp->oldest
	&&
		fp->youngest
	&&
		str_equal(crypto, fp->crypto)
	)
	{
		trace(("file fingerprints match\n"));
		str_free(crypto);
		if (newest > fp->youngest)
			fp->youngest = newest;
		if (oldest < fp->oldest)
			fp->oldest = oldest;
		trace(("return 1;\n"));
		trace((/*{*/"}\n"));
		return 1;
	}

	/*
	 * Everything has changed, reset everything and then say the
	 * file is not the same.
	 */
	fp->oldest = oldest;
	fp->youngest = newest;
	if (fp->crypto)
		str_free(fp->crypto);
	fp->crypto = crypto;
	trace(("file fingerprint mis-match\n"));
	trace(("return 0;\n"));
	trace((/*{*/"}\n"));
	return 0;
}