#include "project.h"


typedef struct {
  ext2_filsys fs;
  ext2_ino_t i_num;
  struct ext2_inode *dst_i;
  ext2_extent_handle_t eh;

  blk64_t l_start;
  blk64_t l_len;

  int ret;

} context_t;

static int make_extents (ext2_filsys fs, blk64_t *b_num,
                         e2_blkcnt_t blockcnt,
                         blk64_t ref_block,
                         int ref_offset,
                         void *_dst)
{
  context_t *dst = (context_t *)_dst;

  if (dst->ret) return BLOCK_ABORT;

  if (!dst->l_len)
    dst->l_start = blockcnt;


  if ((dst->l_start + dst->l_len) != blockcnt) {
    dst->ret = allocate_extent (dst->fs, dst->i_num, dst->eh, dst->l_start, dst->l_len, EXT2_EXTENT_FLAGS_LEAF);

    if (dst->ret) return BLOCK_ABORT;

    dst->dst_i->i_blocks += dst->l_len * (dst->fs->blocksize / 512);

    dst->l_len = 1;
    dst->l_start = blockcnt;
  } else
    dst->l_len++;

  return 0;
}



int clone_blocks (ext2_filsys src_fs, ext2_filsys dst_fs, ext2_ino_t i_num, struct ext2_inode *src_i, struct ext2_inode *dst_i)
{
  context_t dst;
  struct ext2fs_extent e;
  int ret;


  dst.fs = dst_fs;
  dst.i_num = i_num;
  dst.dst_i = dst_i;
  dst.eh = NULL;
  dst.l_start = 0;
  dst.l_len = 0;
  dst.ret = 0;

  do {

    dst_i->i_flags  |= EXT4_EXTENTS_FL;

    EXT2_MOAN_FAIL (ret, ext2fs_extent_open2 (dst_fs, i_num, dst_i, &dst.eh));

    if (ret)
      break;


    EXT2_MOAN_FAIL (ret, ext2fs_block_iterate3 (src_fs, i_num, BLOCK_FLAG_DATA_ONLY | BLOCK_FLAG_READ_ONLY, 0, make_extents, &dst));

    if (ret) break;

    ret = dst.ret;

    if (ret) break;

    if (dst.l_len) {
      ret = allocate_extent (dst_fs, i_num, dst.eh, dst.l_start, dst.l_len, EXT2_EXTENT_FLAGS_LEAF);
      dst_i->i_blocks += dst.l_len * (dst_fs->blocksize / 512);

      if (ret) break;
    }

    EXT2_MOAN_FAIL (ret, ext2fs_write_inode (dst_fs, i_num, dst_i));

    if (ret)
      break;

    ret = ext2fs_extent_get (dst.eh, EXT2_EXTENT_ROOT, &e);

    if (ret == EXT2_ET_EXTENT_NO_NEXT)  {
      ret = 0;
      break;
    }

    if (ret) {
      EXT2_MOAN (ret, "ext2fs_extent_get (dst.eh, EXT2_EXTENT_ROOT, &e)");
      break;
    }


    for (;;) {
      uint64_t file_offset, file_len;


      if ((e.e_flags & EXT2_EXTENT_FLAGS_LEAF) && ! (e.e_flags & EXT2_EXTENT_FLAGS_UNINIT)) {

        file_offset = e.e_lblk;
        file_len = e.e_len;

        file_offset *= src_fs->blocksize;
        file_len *= src_fs->blocksize;


        if (clone_data (src_fs, dst_fs, i_num, src_i, dst_i, file_offset, file_len)) {
          ret = 1;
          break;
        }
      }

      ret = ext2fs_extent_get (dst.eh, EXT2_EXTENT_NEXT_LEAF, &e);

      if (ret == EXT2_ET_EXTENT_NO_NEXT)  {
        ret = 0;
        break;
      }

      if (ret) {
        EXT2_MOAN (ret, "ext2fs_extent_get (dst.eh, EXT2_EXTENT_NEXT_LEAF, &e)");
        break;
      }
    }

  } while (0);

  if (dst.eh)
    ext2fs_extent_free (dst.eh);


  return ret;
}