vcs-svn/svndiff.c

   1 /*
   2  * Licensed under a two-clause BSD-style license.
   3  * See LICENSE for details.
   4  */
   5
   6 #include "git-compat-util.h"
   7 #include "line_buffer.h"
   8 #include "svndiff.h"
   9
  10 /*
  11  * svndiff0 applier
  12  *
  13  * See http://svn.apache.org/repos/asf/subversion/trunk/notes/svndiff.
  14  *
  15  * svndiff0 ::= 'SVN\0' window*
  16  */
  17
  18 static int error_short_read(struct line_buffer *input)
  19 {
  20         if (buffer_ferror(input))
  21                 return error("error reading delta: %s", strerror(errno));
  22         return error("invalid delta: unexpected end of file");
  23 }
  24
  25 static int read_magic(struct line_buffer *in, off_t *len)
  26 {
  27         static const char magic[] = {'S', 'V', 'N', '\0'};
  28         struct strbuf sb = STRBUF_INIT;
  29
  30         if (*len < sizeof(magic) ||
  31             buffer_read_binary(in, &sb, sizeof(magic)) != sizeof(magic))
  32                 return error_short_read(in);
  33
  34         if (memcmp(sb.buf, magic, sizeof(magic)))
  35                 return error("invalid delta: unrecognized file type");
  36
  37         *len -= sizeof(magic);
  38         strbuf_release(&sb);
  39         return 0;
  40 }
  41
  42 int svndiff0_apply(struct line_buffer *delta, off_t delta_len,
  43                         struct sliding_view *preimage, FILE *postimage)
  44 {
  45         assert(delta && preimage && postimage);
  46
  47         if (read_magic(delta, &delta_len))
  48                 return -1;
  49         if (delta_len)
  50                 return error("What do you think I am?  A delta applier?");
  51         return 0;
  52 }