diff-tree-helper.c

   1 #include "cache.h"
   2 #include "strbuf.h"
   3 #include "diff.h"
   4
   5 static int matches_pathspec(const char *name, char **spec, int cnt)
   6 {
   7         int i;
   8         int namelen = strlen(name);
   9         for (i = 0; i < cnt; i++) {
  10                 int speclen = strlen(spec[i]);
  11                 if (! strncmp(spec[i], name, speclen) &&
  12                     speclen <= namelen &&
  13                     (name[speclen] == 0 ||
  14                      name[speclen] == '/'))
  15                         return 1;
  16         }
  17         return 0;
  18 }
  19
  20 static int parse_oneside_change(const char *cp, unsigned char *sha1,
  21                                 char *path) {
  22         int ch;
  23         while ((ch = *cp) && '0' <= ch && ch <= '7')
  24                 cp++; /* skip mode bits */
  25         if (strncmp(cp, "\tblob\t", 6))
  26                 return -1;
  27         cp += 6;
  28         if (get_sha1_hex(cp, sha1))
  29                 return -1;
  30         cp += 40;
  31         if (*cp++ != '\t')
  32                 return -1;
  33         strcpy(path, cp);
  34         return 0;
  35 }
  36
  37 #define STATUS_CACHED    0 /* cached and sha1 valid */
  38 #define STATUS_ABSENT    1 /* diff-tree says old removed or new added */
  39 #define STATUS_UNCACHED  2 /* diff-cache output: read from working tree */
  40
  41 static int parse_diff_tree_output(const char *buf,
  42                                   unsigned char *old_sha1,
  43                                   int *old_status,
  44                                   unsigned char *new_sha1,
  45                                   int *new_status,
  46                                   char *path) {
  47         const char *cp = buf;
  48         int ch;
  49         static unsigned char null_sha[20] = { 0, };
  50
  51         switch (*cp++) {
  52         case '+':
  53                 *old_status = STATUS_ABSENT;
  54                 *new_status = (memcmp(new_sha1, null_sha, sizeof(null_sha)) ?
  55                                STATUS_CACHED : STATUS_UNCACHED);
  56                 return parse_oneside_change(cp, new_sha1, path);
  57         case '-':
  58                 *new_status = STATUS_ABSENT;
  59                 *old_status = (memcmp(old_sha1, null_sha, sizeof(null_sha)) ?
  60                                STATUS_CACHED : STATUS_UNCACHED);
  61                 return parse_oneside_change(cp, old_sha1, path);
  62         case '*':
  63                 break;
  64         default:
  65                 return -1;
  66         }
  67
  68         /* This is for '*' entries */
  69         while ((ch = *cp) && ('0' <= ch && ch <= '7'))
  70                 cp++; /* skip mode bits */
  71         if (strncmp(cp, "->", 2))
  72                 return -1;
  73         cp += 2;
  74         while ((ch = *cp) && ('0' <= ch && ch <= '7'))
  75                 cp++; /* skip mode bits */
  76         if (strncmp(cp, "\tblob\t", 6))
  77                 return -1;
  78         cp += 6;
  79         if (get_sha1_hex(cp, old_sha1))
  80                 return -1;
  81         cp += 40;
  82         if (strncmp(cp, "->", 2))
  83                 return -1;
  84         cp += 2;
  85         if (get_sha1_hex(cp, new_sha1))
  86                 return -1;
  87         cp += 40;
  88         if (*cp++ != '\t')
  89                 return -1;
  90         strcpy(path, cp);
  91         *old_status = (memcmp(old_sha1, null_sha, sizeof(null_sha)) ?
  92                        STATUS_CACHED : STATUS_UNCACHED);
  93         *new_status = (memcmp(new_sha1, null_sha, sizeof(null_sha)) ?
  94                        STATUS_CACHED : STATUS_UNCACHED);
  95         return 0;
  96 }
  97
  98 static int sha1err(const char *path, const unsigned char *sha1)
  99 {
 100         return error("diff-tree-helper: unable to read sha1 file of %s (%s)",
 101                      path, sha1_to_hex(sha1));
 102 }
 103
 104 static int fserr(const char *path)
 105 {
 106         return error("diff-tree-helper: unable to read file %s", path);
 107 }
 108
 109 static char *map_whole_file(const char *path, unsigned long *size) {
 110         int fd;
 111         struct stat st;
 112         void *buf;
 113
 114         if ((fd = open(path, O_RDONLY)) < 0) {
 115                 error("diff-tree-helper: unable to read file %s", path);
 116                 return 0;
 117         }
 118         if (fstat(fd, &st) < 0) {
 119                 close(fd);
 120                 error("diff-tree-helper: unable to stat file %s", path);
 121                 return 0;
 122         }
 123         *size = st.st_size;
 124         buf = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 125         close(fd);
 126         return buf;
 127 }
 128
 129 static int show_diff(const unsigned char *old_sha1, int old_status,
 130                      const unsigned char *new_sha1, int new_status,
 131                      const char *path, int reverse_diff)
 132 {
 133         char other[PATH_MAX];
 134         unsigned long size;
 135         char type[20];
 136         int fd;
 137         int reverse;
 138         void *blob = 0;
 139         const char *fs = 0;
 140         int need_unmap = 0;
 141         int need_unlink = 0;
 142
 143
 144         switch (old_status) {
 145         case STATUS_CACHED:
 146                 blob = read_sha1_file(old_sha1, type, &size);
 147                 if (! blob)
 148                         return sha1err(path, old_sha1);
 149
 150                 switch (new_status) {
 151                 case STATUS_CACHED:
 152                         strcpy(other, ".diff_tree_helper_XXXXXX");
 153                         fd = mkstemp(other);
 154                         if (fd < 0)
 155                                 die("unable to create temp-file");
 156                         if (write(fd, blob, size) != size)
 157                                 die("unable to write temp-file");
 158                         close(fd);
 159                         free(blob);
 160
 161                         blob = read_sha1_file(new_sha1, type, &size);
 162                         if (! blob)
 163                                 return sha1err(path, new_sha1);
 164
 165                         need_unlink = 1;
 166                         /* new = blob, old = fs */
 167                         reverse = !reverse_diff;
 168                         fs = other;
 169                         break;
 170
 171                 case STATUS_ABSENT:
 172                 case STATUS_UNCACHED:
 173                         fs = ((new_status == STATUS_ABSENT) ?
 174                               "/dev/null" : path);
 175                         reverse = reverse_diff;
 176                         break;
 177
 178                 default:
 179                         reverse = reverse_diff;
 180                 }
 181                 break;
 182
 183         case STATUS_ABSENT:
 184                 switch (new_status) {
 185                 case STATUS_CACHED:
 186                         blob = read_sha1_file(new_sha1, type, &size);
 187                         if (! blob)
 188                                 return sha1err(path, new_sha1);
 189                         /* old = fs, new = blob */
 190                         fs = "/dev/null";
 191                         reverse = !reverse_diff;
 192                         break;
 193
 194                 case STATUS_ABSENT:
 195                         return error("diff-tree-helper: absent from both old and new?");
 196                 case STATUS_UNCACHED:
 197                         fs = path;
 198                         blob = strdup("");
 199                         size = 0;
 200                         /* old = blob, new = fs */
 201                         reverse = reverse_diff;
 202                         break;
 203                 default:
 204                         reverse = reverse_diff;
 205                 }
 206                 break;
 207
 208         case STATUS_UNCACHED:
 209                 fs = path; /* old = fs, new = blob */
 210                 reverse = !reverse_diff;
 211
 212                 switch (new_status) {
 213                 case STATUS_CACHED:
 214                         blob = read_sha1_file(new_sha1, type, &size);
 215                         if (! blob)
 216                                 return sha1err(path, new_sha1);
 217                         break;
 218
 219                 case STATUS_ABSENT:
 220                         blob = strdup("");
 221                         size = 0;
 222                         break;
 223
 224                 case STATUS_UNCACHED:
 225                         /* old = fs */
 226                         blob = map_whole_file(path, &size);
 227                         if (! blob)
 228                                 return fserr(path);
 229                         need_unmap = 1;
 230                         break;
 231                 default:
 232                         reverse = reverse_diff;
 233                 }
 234                 break;
 235
 236         default:
 237                 reverse = reverse_diff;
 238         }
 239
 240         if (fs)
 241                 show_differences(fs,
 242                                  path, /* label */
 243                                  blob,
 244                                  size,
 245                                  reverse /* 0: diff blob fs
 246                                             1: diff fs blob */);
 247
 248         if (need_unlink)
 249                 unlink(other);
 250         if (need_unmap && blob)
 251                 munmap(blob, size);
 252         else
 253                 free(blob);
 254         return 0;
 255 }
 256
 257 static const char *diff_tree_helper_usage =
 258 "diff-tree-helper [-R] [-z] paths...";
 259
 260 int main(int ac, char **av) {
 261         struct strbuf sb;
 262         int reverse_diff = 0;
 263         int line_termination = '\n';
 264
 265         strbuf_init(&sb);
 266
 267         while (1 < ac && av[1][0] == '-') {
 268                 if (av[1][1] == 'R')
 269                         reverse_diff = 1;
 270                 else if (av[1][1] == 'z')
 271                         line_termination = 0;
 272                 else
 273                         usage(diff_tree_helper_usage);
 274                 ac--; av++;
 275         }
 276         /* the remaining parameters are paths patterns */
 277
 278         prepare_diff_cmd();
 279
 280         while (1) {
 281                 int old_status, new_status;
 282                 unsigned char old_sha1[20], new_sha1[20];
 283                 char path[PATH_MAX];
 284                 read_line(&sb, stdin, line_termination);
 285                 if (sb.eof)
 286                         break;
 287                 if (parse_diff_tree_output(sb.buf,
 288                                            old_sha1, &old_status,
 289                                            new_sha1, &new_status,
 290                                            path)) {
 291                         fprintf(stderr, "cannot parse %s\n", sb.buf);
 292                         continue;
 293                 }
 294                 if (1 < ac && ! matches_pathspec(path, av+1, ac-1))
 295                         continue;
 296
 297                 show_diff(old_sha1, old_status,
 298                           new_sha1, new_status,
 299                           path, reverse_diff);
 300         }
 301         return 0;
 302 }