/* 
   Copyright (C) Andrew Tridgell 1996
   Copyright (C) Paul Mackerras 1996
   
   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;

#if SUPPORT_HARD_LINKS
static int hlink_compare(struct file_struct *f1,struct file_struct *f2)
{
  if (!S_ISREG(f1->mode) && !S_ISREG(f2->mode)) return 0;
  if (!S_ISREG(f1->mode)) return -1;
  if (!S_ISREG(f2->mode)) return 1;

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

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

  return file_compare(&f1,&f2);
}


static struct file_struct *hlink_list;
static int hlink_count;
#endif

void init_hard_links(struct file_list *flist)
{
#if SUPPORT_HARD_LINKS
	int i;
	if (flist->count < 2) return;

	if (hlink_list) free(hlink_list);
    
	if (!(hlink_list = 
	      (struct file_struct *)malloc(sizeof(hlink_list[0])*flist->count)))
		out_of_memory("init_hard_links");

	for (i = 0; i < flist->count; i++)
		memcpy(&hlink_list[i], flist->files[i], sizeof(hlink_list[0]));

	qsort(hlink_list,flist->count,
	      sizeof(hlink_list[0]),
	      (int (*)())hlink_compare);

	hlink_count=flist->count;
#endif
}

/* check if a file should be skipped because it is the same as an
   earlier hard link */
int check_hard_link(struct file_struct *file)
{
#if SUPPORT_HARD_LINKS
  int low=0,high=hlink_count-1;
  int ret=0;

  if (!hlink_list || !S_ISREG(file->mode)) return 0;

  while (low != high) {
    int mid = (low+high)/2;
    ret = hlink_compare(&hlink_list[mid],file);
    if (ret == 0) {
	    low = mid;
	    break;
    }
    if (ret > 0) 
      high=mid;
    else
      low=mid+1;
  }

  if (hlink_compare(&hlink_list[low],file) != 0) return 0;

  if (low > 0 &&
      S_ISREG(hlink_list[low-1].mode) &&
      file->dev == hlink_list[low-1].dev &&
      file->inode == hlink_list[low-1].inode)
    return 1;
#endif

  return 0;
}


#if SUPPORT_HARD_LINKS
static void hard_link_one(int i)
{
	STRUCT_STAT st1,st2;

	if (link_stat(f_name(&hlink_list[i-1]),&st1) != 0) return;

	if (link_stat(f_name(&hlink_list[i]),&st2) != 0) {
		if (do_link(f_name(&hlink_list[i-1]),f_name(&hlink_list[i])) != 0) {
			if (verbose > 0)
				rprintf(FINFO,"link %s => %s : %s\n",
					f_name(&hlink_list[i]),
					f_name(&hlink_list[i-1]),strerror(errno));
			return;
		}
	} else {
		if (st2.st_dev == st1.st_dev && st2.st_ino == st1.st_ino) return;
		
		if (robust_unlink(f_name(&hlink_list[i])) != 0 ||
		    do_link(f_name(&hlink_list[i-1]),f_name(&hlink_list[i])) != 0) {
			if (verbose > 0)
				rprintf(FINFO,"link %s => %s : %s\n",
					f_name(&hlink_list[i]),
					f_name(&hlink_list[i-1]),strerror(errno));
			return;
		}
	}
	if (verbose > 0)
		rprintf(FINFO,"%s => %s\n",
			f_name(&hlink_list[i]),f_name(&hlink_list[i-1]));
}
#endif

/* create any hard links in the flist */
void do_hard_links(struct file_list *flist)
{
#if SUPPORT_HARD_LINKS
	int i;
  
	if (!hlink_list) return;

	for (i=1;i<hlink_count;i++) {
		if (S_ISREG(hlink_list[i].mode) &&
		    S_ISREG(hlink_list[i-1].mode) &&
		    hlink_list[i].basename && hlink_list[i-1].basename &&
		    hlink_list[i].dev == hlink_list[i-1].dev &&
		    hlink_list[i].inode == hlink_list[i-1].inode) {
			hard_link_one(i);
		}	
	}
#endif
}