src/ident.c

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7
   8 #include "git2/sys/filter.h"
   9 #include "filter.h"
  10 #include "buffer.h"
  11 #include "buf_text.h"
  12
  13 static int ident_find_id(
  14         const char **id_start, const char **id_end, const char *start, size_t len)
  15 {
  16         const char *end = start + len, *found = NULL;
  17
  18         while (len > 3 && (found = memchr(start, '$', len)) != NULL) {
  19                 size_t remaining = (size_t)(end - found) - 1;
  20                 if (remaining < 3)
  21                         return GIT_ENOTFOUND;
  22
  23                 start = found + 1;
  24                 len   = remaining;
  25
  26                 if (start[0] == 'I' && start[1] == 'd')
  27                         break;
  28         }
  29
  30         if (len < 3 || !found)
  31                 return GIT_ENOTFOUND;
  32         *id_start = found;
  33
  34         if ((found = memchr(start + 2, '$', len - 2)) == NULL)
  35                 return GIT_ENOTFOUND;
  36
  37         *id_end = found + 1;
  38         return 0;
  39 }
  40
  41 static int ident_insert_id(
  42         git_buf *to, const git_buf *from, const git_filter_source *src)
  43 {
  44         char oid[GIT_OID_HEXSZ+1];
  45         const char *id_start, *id_end, *from_end = from->ptr + from->size;
  46         size_t need_size;
  47
  48         /* replace $Id$ with blob id */
  49
  50         if (!git_filter_source_id(src))
  51                 return GIT_PASSTHROUGH;
  52
  53         git_oid_tostr(oid, sizeof(oid), git_filter_source_id(src));
  54
  55         if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  56                 return GIT_PASSTHROUGH;
  57
  58         need_size = (size_t)(id_start - from->ptr) +
  59                 5 /* "$Id: " */ + GIT_OID_HEXSZ + 1 /* "$" */ +
  60                 (size_t)(from_end - id_end);
  61
  62         if (git_buf_grow(to, need_size) < 0)
  63                 return -1;
  64
  65         git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
  66         git_buf_put(to, "$Id: ", 5);
  67         git_buf_put(to, oid, GIT_OID_HEXSZ);
  68         git_buf_putc(to, '$');
  69         git_buf_put(to, id_end, (size_t)(from_end - id_end));
  70
  71         return git_buf_oom(to) ? -1 : 0;
  72 }
  73
  74 static int ident_remove_id(
  75         git_buf *to, const git_buf *from)
  76 {
  77         const char *id_start, *id_end, *from_end = from->ptr + from->size;
  78         size_t need_size;
  79
  80         if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  81                 return GIT_PASSTHROUGH;
  82
  83         need_size = (size_t)(id_start - from->ptr) +
  84                 4 /* "$Id$" */ + (size_t)(from_end - id_end);
  85
  86         if (git_buf_grow(to, need_size) < 0)
  87                 return -1;
  88
  89         git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
  90         git_buf_put(to, "$Id$", 4);
  91         git_buf_put(to, id_end, (size_t)(from_end - id_end));
  92
  93         return git_buf_oom(to) ? -1 : 0;
  94 }
  95
  96 static int ident_apply(
  97         git_filter     *self,
  98         void          **payload,
  99         git_buf        *to,
 100         const git_buf  *from,
 101         const git_filter_source *src)
 102 {
 103         GIT_UNUSED(self); GIT_UNUSED(payload);
 104
 105         /* Don't filter binary files */
 106         if (git_buf_text_is_binary(from))
 107                 return GIT_PASSTHROUGH;
 108
 109         if (git_filter_source_mode(src) == GIT_FILTER_SMUDGE)
 110                 return ident_insert_id(to, from, src);
 111         else
 112                 return ident_remove_id(to, from);
 113 }
 114
 115 git_filter *git_ident_filter_new(void)
 116 {
 117         git_filter *f = git__calloc(1, sizeof(git_filter));
 118         if (f == NULL)
 119                 return NULL;
 120
 121         f->version = GIT_FILTER_VERSION;
 122         f->attributes = "+ident"; /* apply to files with ident attribute set */
 123         f->shutdown = git_filter_free;
 124         f->apply    = ident_apply;
 125
 126         return f;
 127 }