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 "common.h"
   9
  10 #include "git2/sys/filter.h"
  11 #include "filter.h"
  12 #include "buffer.h"
  13 #include "buf_text.h"
  14
  15 static int ident_find_id(
  16         const char **id_start, const char **id_end, const char *start, size_t len)
  17 {
  18         const char *end = start + len, *found = NULL;
  19
  20         while (len > 3 && (found = memchr(start, '$', len)) != NULL) {
  21                 size_t remaining = (size_t)(end - found) - 1;
  22                 if (remaining < 3)
  23                         return GIT_ENOTFOUND;
  24
  25                 start = found + 1;
  26                 len   = remaining;
  27
  28                 if (start[0] == 'I' && start[1] == 'd')
  29                         break;
  30         }
  31
  32         if (len < 3 || !found)
  33                 return GIT_ENOTFOUND;
  34         *id_start = found;
  35
  36         if ((found = memchr(start + 2, '$', len - 2)) == NULL)
  37                 return GIT_ENOTFOUND;
  38
  39         *id_end = found + 1;
  40         return 0;
  41 }
  42
  43 static int ident_insert_id(
  44         git_buf *to, const git_buf *from, const git_filter_source *src)
  45 {
  46         char oid[GIT_OID_HEXSZ+1];
  47         const char *id_start, *id_end, *from_end = from->ptr + from->size;
  48         size_t need_size;
  49
  50         /* replace $Id$ with blob id */
  51
  52         if (!git_filter_source_id(src))
  53                 return GIT_PASSTHROUGH;
  54
  55         git_oid_tostr(oid, sizeof(oid), git_filter_source_id(src));
  56
  57         if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  58                 return GIT_PASSTHROUGH;
  59
  60         need_size = (size_t)(id_start - from->ptr) +
  61                 5 /* "$Id: " */ + GIT_OID_HEXSZ + 2 /* " $" */ +
  62                 (size_t)(from_end - id_end);
  63
  64         if (git_buf_grow(to, need_size) < 0)
  65                 return -1;
  66
  67         git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
  68         git_buf_put(to, "$Id: ", 5);
  69         git_buf_put(to, oid, GIT_OID_HEXSZ);
  70         git_buf_put(to, " $", 2);
  71         git_buf_put(to, id_end, (size_t)(from_end - id_end));
  72
  73         return git_buf_oom(to) ? -1 : 0;
  74 }
  75
  76 static int ident_remove_id(
  77         git_buf *to, const git_buf *from)
  78 {
  79         const char *id_start, *id_end, *from_end = from->ptr + from->size;
  80         size_t need_size;
  81
  82         if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  83                 return GIT_PASSTHROUGH;
  84
  85         need_size = (size_t)(id_start - from->ptr) +
  86                 4 /* "$Id$" */ + (size_t)(from_end - id_end);
  87
  88         if (git_buf_grow(to, need_size) < 0)
  89                 return -1;
  90
  91         git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
  92         git_buf_put(to, "$Id$", 4);
  93         git_buf_put(to, id_end, (size_t)(from_end - id_end));
  94
  95         return git_buf_oom(to) ? -1 : 0;
  96 }
  97
  98 static int ident_apply(
  99         git_filter     *self,
 100         void          **payload,
 101         git_buf        *to,
 102         const git_buf  *from,
 103         const git_filter_source *src)
 104 {
 105         GIT_UNUSED(self); GIT_UNUSED(payload);
 106
 107         /* Don't filter binary files */
 108         if (git_buf_text_is_binary(from))
 109                 return GIT_PASSTHROUGH;
 110
 111         if (git_filter_source_mode(src) == GIT_FILTER_SMUDGE)
 112                 return ident_insert_id(to, from, src);
 113         else
 114                 return ident_remove_id(to, from);
 115 }
 116
 117 git_filter *git_ident_filter_new(void)
 118 {
 119         git_filter *f = git__calloc(1, sizeof(git_filter));
 120         if (f == NULL)
 121                 return NULL;
 122
 123         f->version = GIT_FILTER_VERSION;
 124         f->attributes = "+ident"; /* apply to files with ident attribute set */
 125         f->shutdown = git_filter_free;
 126         f->apply    = ident_apply;
 127
 128         return f;
 129 }