From: Duy Nguyen <pclouds@gmail.com>
Date: Tue, 20 Aug 2013 14:16:41 GMT
Subject: Re: [PATCH v3 15/24] read-cache: read index-v5
Message-ID: <CACsJy8CNHNj6dScPUCiRnv=zqT9QfY+=v3ECsnUR2uR4nkFQHg@mail.gmail.com>
In-Reply-To: <1376854933-31241-16-git-send-email-t.gummerer@gmail.com>

On Mon, Aug 19, 2013 at 2:42 AM, Thomas Gummerer <t.gummerer@gmail.com> wrote:
> +static int read_entry(struct cache_entry **ce, char *pathname, size_t pathlen,
> +                     void *mmap, unsigned long mmap_size,
> +                     unsigned int first_entry_offset,
> +                     unsigned int foffsetblock)
> +{
> +       int len, offset_to_offset;
> +       char *name;
> +       uint32_t foffsetblockcrc, *filecrc, *beginning, *end, entry_offset;
> +       struct ondisk_cache_entry *disk_ce;
> +
> +       beginning = ptr_add(mmap, foffsetblock);
> +       end = ptr_add(mmap, foffsetblock + 4);
> +       len = ntoh_l(*end) - ntoh_l(*beginning) - sizeof(struct ondisk_cache_entry) - 5;
> +       entry_offset = first_entry_offset + ntoh_l(*beginning);
> +       name = ptr_add(mmap, entry_offset);
> +       disk_ce = ptr_add(mmap, entry_offset + len + 1);
> +       *ce = cache_entry_from_ondisk(disk_ce, pathname, name, len, pathlen);
> +       filecrc = ptr_add(mmap, entry_offset + len + 1 + sizeof(*disk_ce));
> +       offset_to_offset = htonl(foffsetblock);
> +       foffsetblockcrc = crc32(0, (Bytef*)&offset_to_offset, 4);
> +       if (!check_crc32(foffsetblockcrc,
> +               ptr_add(mmap, entry_offset), len + 1 + sizeof(*disk_ce),
> +               ntoh_l(*filecrc)))
> +               return -1;
> +
> +       return 0;
> +}

Last thought before book+bed time. I wonder if moving the name part to
the end of the entry (i.e. chaging on disk format) would simplify this
code. The new ondisk_cache_entry would be something like this

struct ondisk_cache_entry {
   uint16_t flags;
   uint16_t mode;
   struct cache_time mtime;
   uint32_t size;
   int stat_crc;
   unsigned char sha1[20];
   char name[FLEX_ARRAY];
};
-- 
Duy