Re: [PATCH 18/22] read-cache: write index-v5

> Write the index version 5 file format to disk. This version doesn't
> write the cache-tree data and resolve-undo data to the file.
>
> The main work is done when filtering out the directories from the
> current in-memory format, where in the same turn also the conflicts
> and the file data is calculated.
>
> Helped-by: Nguyen Thai Ngoc Duy <pclouds@gmail.com>
> Helped-by: Thomas Rast <trast@student.ethz.ch>
> Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
> ---
> diff --git a/read-cache-v5.c b/read-cache-v5.c
> index f1ad132..f056f6b 100644
> --- a/read-cache-v5.c
> +++ b/read-cache-v5.c
> +static int write_index_v5(struct index_state *istate, int newfd)
> +{
> +       struct cache_version_header hdr;
> +       struct cache_header hdr_v5;
> +       struct cache_entry **cache = istate->cache;
> +       struct directory_entry *de;
> +       struct ondisk_directory_entry *ondisk;
> +       int entries = istate->cache_nr;
> +       int i, removed, non_conflicted, total_dir_len, ondisk_directory_size;
> +       int total_file_len, conflict_offset, offset_to_offset;
> +       unsigned int ndir;
> +       uint32_t crc;
> +
> +       if (istate->partially_read)
> +               die("BUG: index: cannot write a partially read index");
> +
> +       for (i = removed = 0; i < entries; i++) {
> +               if (cache[i]->ce_flags & CE_REMOVE)
> +                       removed++;
> +       }
> +       hdr.hdr_signature = htonl(CACHE_SIGNATURE);
> +       hdr.hdr_version = htonl(istate->version);
> +       hdr_v5.hdr_nfile = htonl(entries - removed);
> +       hdr_v5.hdr_nextension = htonl(0); /* Currently no extensions are supported */
> +
> +       non_conflicted = 0;
> +       total_dir_len = 0;
> +       total_file_len = 0;
> +       de = compile_directory_data(istate, entries, &ndir, &non_conflicted,
> +                       &total_dir_len, &total_file_len);
> +       hdr_v5.hdr_ndir = htonl(ndir);
> +
> +       /*
> +        * This is needed because the compiler aligns structs to sizes multipe

> +        * of 4
> +        */
> +       ondisk_directory_size = sizeof(ondisk->flags)
> +               + sizeof(ondisk->foffset)
> +               + sizeof(ondisk->cr)
> +               + sizeof(ondisk->ncr)
> +               + sizeof(ondisk->nsubtrees)
> +               + sizeof(ondisk->nfiles)
> +               + sizeof(ondisk->nentries)
> +               + sizeof(ondisk->sha1);
> +       hdr_v5.hdr_fblockoffset = htonl(sizeof(hdr) + sizeof(hdr_v5) + 4
> +               + (ndir + 1) * 4
> +               + total_dir_len
> +               + ndir * (ondisk_directory_size + 4)
> +               + (non_conflicted + 1) * 4);
> +
> +       crc = 0;
> +       if (ce_write(&crc, newfd, &hdr, sizeof(hdr)) < 0)
> +               return -1;
> +       if (ce_write(&crc, newfd, &hdr_v5, sizeof(hdr_v5)) < 0)
> +               return -1;
> +       crc = htonl(crc);
> +       if (ce_write(NULL, newfd, &crc, 4) < 0)
> +               return -1;
> +
> +       conflict_offset = sizeof(hdr) + sizeof(hdr_v5) + 4
> +               + (ndir + 1) * 4
> +               + total_dir_len
> +               + ndir * (ondisk_directory_size + 4)
> +               + (non_conflicted + 1) * 4
> +               + total_file_len
> +               + non_conflicted * (sizeof(struct ondisk_cache_entry) + 4);
> +       if (write_directories(de, newfd, conflict_offset) < 0)
> +               return -1;
> +       offset_to_offset = sizeof(hdr) + sizeof(hdr_v5) + 4
> +               + (ndir + 1) * 4
> +               + total_dir_len
> +               + ndir * (ondisk_directory_size + 4);
> +       if (write_entries(istate, de, entries, newfd, offset_to_offset) < 0)
> +               return -1;
> +       if (write_conflicts(istate, de, newfd) < 0)
> +               return -1;
> +       return ce_flush(newfd);
> +}
> +