/*
   Copyright (C) Andrew Tridgell 1996
   Copyright (C) Paul Mackerras 1996
   Copyright (C) 2002 by Martin Pool <mbp@samba.org>

   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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rsync.h"

extern int dry_run;
extern int verbose;
extern int make_backups;
extern struct file_list *the_file_list;

#ifdef SUPPORT_HARD_LINKS

#define FPTR(i) (the_file_list->files[i])
#define LINKED(p1,p2) (FPTR(p1)->F_DEV == FPTR(p2)->F_DEV \
		    && FPTR(p1)->F_INODE == FPTR(p2)->F_INODE)

static int hlink_compare(int *int1, int *int2)
{
	struct file_struct *f1 = FPTR(*int1);
	struct file_struct *f2 = FPTR(*int2);

	if (f1->F_DEV != f2->F_DEV)
		return (int) (f1->F_DEV > f2->F_DEV ? 1 : -1);

	if (f1->F_INODE != f2->F_INODE)
		return (int) (f1->F_INODE > f2->F_INODE ? 1 : -1);

	return f_name_cmp(f1, f2);
}

static int *hlink_list;
static int hlink_count;

/* Analyze the data in the hlink_list[], remove items that aren't multiply
 * linked, and replace the dev+inode data with the hlindex+next linked list. */
static void link_idev_data(void)
{
	int head, from, to, start;

	alloc_pool_t hlink_pool;
	alloc_pool_t idev_pool = the_file_list->hlink_pool;

	hlink_pool = pool_create(128 * 1024, sizeof (struct hlink),
	    out_of_memory, POOL_INTERN);

	for (from = to = 0; from < hlink_count; from++) {
		start = from;
		head = hlink_list[start];
		while (from < hlink_count-1
		    && LINKED(hlink_list[from], hlink_list[from+1])) {
			pool_free(idev_pool, 0, FPTR(hlink_list[from])->link_u.idev);
			FPTR(hlink_list[from])->link_u.links = pool_talloc(hlink_pool,
			    struct hlink, 1, "hlink_list");

			FPTR(hlink_list[from])->F_HLINDEX = to;
			FPTR(hlink_list[from])->F_NEXT = hlink_list[from+1];
			from++;
		}
		if (from > start) {
			pool_free(idev_pool, 0, FPTR(hlink_list[from])->link_u.idev);
			FPTR(hlink_list[from])->link_u.links = pool_talloc(hlink_pool,
			    struct hlink, 1, "hlink_list");

			FPTR(head)->flags |= FLAG_HLINK_TOL;
			FPTR(hlink_list[from])->F_HLINDEX = to;
			FPTR(hlink_list[from])->F_NEXT = head;
			FPTR(hlink_list[from])->flags |= FLAG_HLINK_EOL;
			hlink_list[to++] = head;
		} else {
			pool_free(idev_pool, 0, FPTR(head)->link_u.idev);
			FPTR(head)->link_u.idev = NULL;
		}
	}

	if (!to) {
		free(hlink_list);
		hlink_list = NULL;
		pool_destroy(hlink_pool);
		hlink_pool = NULL;
	} else {
		hlink_count = to;
		hlink_list = realloc_array(hlink_list, int, hlink_count);
		if (!hlink_list)
			out_of_memory("init_hard_links");
	}
	the_file_list->hlink_pool = hlink_pool;
	pool_destroy(idev_pool);
}
#endif

void init_hard_links(void)
{
#ifdef SUPPORT_HARD_LINKS
	int i;

	if (the_file_list->count < 2)
		return;

	if (hlink_list)
		free(hlink_list);

	if (!(hlink_list = new_array(int, the_file_list->count)))
		out_of_memory("init_hard_links");

	hlink_count = 0;
	for (i = 0; i < the_file_list->count; i++) {
		if (FPTR(i)->link_u.idev)
			hlink_list[hlink_count++] = i;
	}

	qsort(hlink_list, hlink_count,
	    sizeof hlink_list[0], (int (*)()) hlink_compare);

	if (!hlink_count) {
		free(hlink_list);
		hlink_list = NULL;
	} else
		link_idev_data();
#endif
}

int hard_link_check(struct file_struct *file, int ndx, int skip)
{
#ifdef SUPPORT_HARD_LINKS
	if (!hlink_list || !file->link_u.links)
		return 0;
	if (skip && !(file->flags & FLAG_HLINK_EOL))
		hlink_list[file->F_HLINDEX] = file->F_NEXT;
	if (hlink_list[file->F_HLINDEX] != ndx) {
		if (verbose > 2) {
			rprintf(FINFO, "\"%s\" is a hard link\n",
				safe_fname(f_name(file)));
		}
		return 1;
	}
#endif
	return 0;
}

#ifdef SUPPORT_HARD_LINKS
int hard_link_one(struct file_struct *file, int ndx, char *fname,
		  int statret, STRUCT_STAT *st, char *toname, int terse,
		  int itemizing, enum logcode code)
{
	if (do_link(toname, fname)) {
		if (verbose) {
			rsyserr(FERROR, errno, "link %s => %s failed",
				full_fname(fname), safe_fname(toname));
		}
		return -1;
	}

	if (itemizing) {
		itemize(file, ndx, statret, st,
			ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS, 0,
			terse ? "" : toname);
	}
	if (code && verbose && !terse) {
		rprintf(code, "%s => %s\n",
			safe_fname(fname), safe_fname(toname));
	}
	return 0;
}
#endif


void hard_link_cluster(struct file_struct *file, int master, int itemizing,
		       enum logcode code)
{
#ifdef SUPPORT_HARD_LINKS
	char hlink1[MAXPATHLEN];
	char *hlink2;
	STRUCT_STAT st1, st2;
	int statret, ndx = master;

	if (link_stat(f_name_to(file, hlink1), &st1, 0) < 0)
		return;
	if (!(file->flags & FLAG_HLINK_TOL)) {
		while (!(file->flags & FLAG_HLINK_EOL)) {
			ndx = file->F_NEXT;
			file = FPTR(ndx);
		}
	}
	do {
		ndx = file->F_NEXT;
		file = FPTR(ndx);
		if (ndx == master)
			continue;
		hlink2 = f_name(file);
		if ((statret = link_stat(hlink2, &st2, 0)) == 0) {
			if (st2.st_dev == st1.st_dev
			    && st2.st_ino == st1.st_ino) {
				if (itemizing) {
					itemize(file, ndx, statret, &st2,
						ITEM_LOCAL_CHANGE | ITEM_XNAME_FOLLOWS,
						0, "");
				}
				continue;
			}
			if (make_backups) {
				if (!make_backup(hlink2))
					continue;
			} else if (robust_unlink(hlink2)) {
				if (verbose > 0) {
					rsyserr(FINFO, errno,
						"unlink %s failed",
						full_fname(hlink2));
				}
				continue;
			}
		}
		hard_link_one(file, ndx, hlink2, statret,
			      &st2, hlink1, 0, itemizing, code);
	} while (!(file->flags & FLAG_HLINK_EOL));
#endif
}