/*
 *	cook - file construction tool
 *	Copyright (C) 1994, 1997, 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 fingerprints
 */

#include <ac/errno.h>
#include <ac/fcntl.h>
#include <ac/unistd.h>
#include <ac/dirent.h>

#include <sys/types.h>
#include <sys/stat.h>

#include <fp.h>
#include <str_list.h>
#include <mem.h>


fingerprint_ty *
fingerprint_new(mp)
	fingerprint_methods_ty *mp;
{
	fingerprint_ty	*fp;

	fp = mem_alloc(mp->size);
	fp->method = mp;
	mp->constructor(fp);
	return fp;
}


void
fingerprint_delete(fp)
	fingerprint_ty	*fp;
{
	fp->method->destructor(fp);
	mem_free(fp);
}


static int fingerprint_scan_dir _((fingerprint_ty *, char *));

static int
fingerprint_scan_dir(fp, fn)
	fingerprint_ty	*fp;
	char		*fn;
{
	DIR		*dp;
	string_list_ty	wl;
	string_ty	*s;
	size_t		j;

	/*
	 * Read the directory contents, and remember the names.
	 * Don't hash it just yet.
	 */
	dp = opendir(fn);
	if (!dp)
		return -1;
	string_list_constructor(&wl);
	for (;;)
	{
		struct dirent	*dep;

		dep = readdir(dp);
		if (!dep)
			break;
		s = str_from_c(dep->d_name);
		string_list_append(&wl, s);
		str_free(s);
	}
	closedir(dp);

	/*
	 * Sort the names before we hash anything.  That way, even if
	 * the files in the directory get re-arranged, the hash stays
	 * the same.  This is common when a file is deleted, and then
	 * re-created in identical form.
	 */
	string_list_sort(&wl);

	/*
	 * Now hash the strings in the list.  This takes advantage of
	 * the fact that all the strings are NUL terminated to introduce
	 * a unique separator.
	 */
	for (j = 0; j < wl.nstrings; ++j)
	{
		s = wl.string[j];
		fingerprint_addn(fp, s->str_text, s->str_length + 1);
	}
	string_list_destructor(&wl);
	return 0;
}


static int fingerprint_scan _((fingerprint_ty *, char *));

static int
fingerprint_scan(fp, fn)
	fingerprint_ty	*fp;
	char		*fn;
{
	int		fd;
	unsigned char	ibuf[1024];
	long		nbytes;
	int		err;

	if (fn)
	{
		struct stat st;

#ifdef __CYGWIN32__
		/*
		 * This is probably a side effect of a WindowsNT-ism.
		 * You can't call CygWin32's open() on a directory.
		 * This will slow us down a tad.
		 */
		if (stat(fn, &st) == 0 && S_ISDIR(st.st_mode))
			return fingerprint_scan_dir(fp, fn);
#endif
		fd = open(fn, O_RDONLY, 0666);
		if (fd < 0)
			return -1;
#ifndef __CYGWIN32__
		/*
		 * The most common case is to obtain a fingerprint for
		 * a file. In the rare cases it is a directory, perform
		 * the stat *after* the open call, and save ourselves
		 * a second pathname walk to obtain the inode info.
		 */
		if (fstat(fd, &st) == 0 && S_ISDIR(st.st_mode))
		{
			close(fd);
			return fingerprint_scan_dir(fp, fn);
		}
#endif
	}
	else
		fd = 0;
	for (;;)
	{
		nbytes = read(fd, ibuf, sizeof(ibuf));
		if (nbytes < 0)
		{
			if (fn)
			{
				err = errno;
				close(fd);
				errno = err;
			}
			return -1;
		}
		if (nbytes == 0)
			break;
		fingerprint_addn(fp, ibuf, nbytes);
	}
	if (fn && close(fd) < 0)
		return -1;
	return 0;
}


int
fingerprint_file_hash(fp, fn, obuf)
	fingerprint_ty	*fp;
	char		*fn;
	unsigned char	*obuf;
{
	if (fingerprint_scan(fp, fn))
		return -1;
	return fingerprint_hash(fp, obuf);
}


int
fingerprint_file_sum(fp, fn, obuf)
	fingerprint_ty	*fp;
	char		*fn;
	char		*obuf;
{
	if (fingerprint_scan(fp, fn))
		return -1;
	fingerprint_sum(fp, obuf);
	return 0;
}


void
fingerprint_add(p, c)
	fingerprint_ty	*p;
	int		c;
{
	unsigned char	buf;

	buf = c;
	fingerprint_addn(p, &buf, 1);
}