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 "str.h"
  13
  14 static int ident_find_id(
  15         const char **id_start, const char **id_end, const char *start, size_t len)
  16 {
  17         const char *end = start + len, *found = NULL;
  18
  19         while (len > 3 && (found = memchr(start, '$', len)) != NULL) {
  20                 size_t remaining = (size_t)(end - found) - 1;
  21                 if (remaining < 3)
  22                         return GIT_ENOTFOUND;
  23
  24                 start = found + 1;
  25                 len   = remaining;
  26
  27                 if (start[0] == 'I' && start[1] == 'd')
  28                         break;
  29         }
  30
  31         if (len < 3 || !found)
  32                 return GIT_ENOTFOUND;
  33         *id_start = found;
  34
  35         if ((found = memchr(start + 2, '$', len - 2)) == NULL)
  36                 return GIT_ENOTFOUND;
  37
  38         *id_end = found + 1;
  39         return 0;
  40 }
  41
  42 static int ident_insert_id(
  43         git_str *to, const git_str *from, const git_filter_source *src)
  44 {
  45         char oid[GIT_OID_HEXSZ+1];
  46         const char *id_start, *id_end, *from_end = from->ptr + from->size;
  47         size_t need_size;
  48
  49         /* replace $Id$ with blob id */
  50
  51         if (!git_filter_source_id(src))
  52                 return GIT_PASSTHROUGH;
  53
  54         git_oid_tostr(oid, sizeof(oid), git_filter_source_id(src));
  55
  56         if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  57                 return GIT_PASSTHROUGH;
  58
  59         need_size = (size_t)(id_start - from->ptr) +
  60                 5 /* "$Id: " */ + GIT_OID_HEXSZ + 2 /* " $" */ +
  61                 (size_t)(from_end - id_end);
  62
  63         if (git_str_grow(to, need_size) < 0)
  64                 return -1;
  65
  66         git_str_set(to, from->ptr, (size_t)(id_start - from->ptr));
  67         git_str_put(to, "$Id: ", 5);
  68         git_str_put(to, oid, GIT_OID_HEXSZ);
  69         git_str_put(to, " $", 2);
  70         git_str_put(to, id_end, (size_t)(from_end - id_end));
  71
  72         return git_str_oom(to) ? -1 : 0;
  73 }
  74
  75 static int ident_remove_id(
  76         git_str *to, const git_str *from)
  77 {
  78         const char *id_start, *id_end, *from_end = from->ptr + from->size;
  79         size_t need_size;
  80
  81         if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  82                 return GIT_PASSTHROUGH;
  83
  84         need_size = (size_t)(id_start - from->ptr) +
  85                 4 /* "$Id$" */ + (size_t)(from_end - id_end);
  86
  87         if (git_str_grow(to, need_size) < 0)
  88                 return -1;
  89
  90         git_str_set(to, from->ptr, (size_t)(id_start - from->ptr));
  91         git_str_put(to, "$Id$", 4);
  92         git_str_put(to, id_end, (size_t)(from_end - id_end));
  93
  94         return git_str_oom(to) ? -1 : 0;
  95 }
  96
  97 static int ident_apply(
  98         git_filter     *self,
  99         void          **payload,
 100         git_str        *to,
 101         const git_str  *from,
 102         const git_filter_source *src)
 103 {
 104         GIT_UNUSED(self); GIT_UNUSED(payload);
 105
 106         /* Don't filter binary files */
 107         if (git_str_is_binary(from))
 108                 return GIT_PASSTHROUGH;
 109
 110         if (git_filter_source_mode(src) == GIT_FILTER_SMUDGE)
 111                 return ident_insert_id(to, from, src);
 112         else
 113                 return ident_remove_id(to, from);
 114 }
 115
 116 static int ident_stream(
 117         git_writestream **out,
 118         git_filter *self,
 119         void **payload,
 120         const git_filter_source *src,
 121         git_writestream *next)
 122 {
 123         return git_filter_buffered_stream_new(out,
 124                 self, ident_apply, NULL, payload, src, next);
 125 }
 126
 127 git_filter *git_ident_filter_new(void)
 128 {
 129         git_filter *f = git__calloc(1, sizeof(git_filter));
 130         if (f == NULL)
 131                 return NULL;
 132
 133         f->version = GIT_FILTER_VERSION;
 134         f->attributes = "+ident"; /* apply to files with ident attribute set */
 135         f->shutdown = git_filter_free;
 136         f->stream   = ident_stream;
 137
 138         return f;
 139 }