diff-tree.c

   1 #include "cache.h"
   2
   3 static int recursive = 0;
   4 static int line_termination = '\n';
   5
   6 // What paths are we interested in?
   7 static int nr_paths = 0;
   8 static char **paths = NULL;
   9 static int *pathlens = NULL;
  10
  11 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base);
  12
  13 static void update_tree_entry(void **bufp, unsigned long *sizep)
  14 {
  15         void *buf = *bufp;
  16         unsigned long size = *sizep;
  17         int len = strlen(buf) + 1 + 20;
  18
  19         if (size < len)
  20                 die("corrupt tree file");
  21         *bufp = buf + len;
  22         *sizep = size - len;
  23 }
  24
  25 static const unsigned char *extract(void *tree, unsigned long size, const char **pathp, unsigned int *modep)
  26 {
  27         int len = strlen(tree)+1;
  28         const unsigned char *sha1 = tree + len;
  29         const char *path = strchr(tree, ' ');
  30
  31         if (!path || size < len + 20 || sscanf(tree, "%o", modep) != 1)
  32                 die("corrupt tree file");
  33         *pathp = path+1;
  34         return sha1;
  35 }
  36
  37 static char *malloc_base(const char *base, const char *path, int pathlen)
  38 {
  39         int baselen = strlen(base);
  40         char *newbase = malloc(baselen + pathlen + 2);
  41         memcpy(newbase, base, baselen);
  42         memcpy(newbase + baselen, path, pathlen);
  43         memcpy(newbase + baselen + pathlen, "/", 2);
  44         return newbase;
  45 }
  46
  47 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base);
  48
  49 /* A whole sub-tree went away or appeared */
  50 static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base)
  51 {
  52         while (size) {
  53                 show_file(prefix, tree, size, base);
  54                 update_tree_entry(&tree, &size);
  55         }
  56 }
  57
  58 /* A file entry went away or appeared */
  59 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base)
  60 {
  61         unsigned mode;
  62         const char *path;
  63         const unsigned char *sha1 = extract(tree, size, &path, &mode);
  64
  65         if (recursive && S_ISDIR(mode)) {
  66                 char type[20];
  67                 unsigned long size;
  68                 char *newbase = malloc_base(base, path, strlen(path));
  69                 void *tree;
  70
  71                 tree = read_sha1_file(sha1, type, &size);
  72                 if (!tree || strcmp(type, "tree"))
  73                         die("corrupt tree sha %s", sha1_to_hex(sha1));
  74
  75                 show_tree(prefix, tree, size, newbase);
  76
  77                 free(tree);
  78                 free(newbase);
  79                 return;
  80         }
  81
  82         printf("%s%o\t%s\t%s\t%s%s%c", prefix, mode,
  83                S_ISDIR(mode) ? "tree" : "blob",
  84                sha1_to_hex(sha1), base, path,
  85                line_termination);
  86 }
  87
  88 static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
  89 {
  90         unsigned mode1, mode2;
  91         const char *path1, *path2;
  92         const unsigned char *sha1, *sha2;
  93         int cmp, pathlen1, pathlen2;
  94         char old_sha1_hex[50];
  95
  96         sha1 = extract(tree1, size1, &path1, &mode1);
  97         sha2 = extract(tree2, size2, &path2, &mode2);
  98
  99         pathlen1 = strlen(path1);
 100         pathlen2 = strlen(path2);
 101         cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
 102         if (cmp < 0) {
 103                 show_file("-", tree1, size1, base);
 104                 return -1;
 105         }
 106         if (cmp > 0) {
 107                 show_file("+", tree2, size2, base);
 108                 return 1;
 109         }
 110         if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
 111                 return 0;
 112
 113         /*
 114          * If the filemode has changed to/from a directory from/to a regular
 115          * file, we need to consider it a remove and an add.
 116          */
 117         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
 118                 show_file("-", tree1, size1, base);
 119                 show_file("+", tree2, size2, base);
 120                 return 0;
 121         }
 122
 123         if (recursive && S_ISDIR(mode1)) {
 124                 int retval;
 125                 char *newbase = malloc_base(base, path1, pathlen1);
 126                 retval = diff_tree_sha1(sha1, sha2, newbase);
 127                 free(newbase);
 128                 return retval;
 129         }
 130
 131         strcpy(old_sha1_hex, sha1_to_hex(sha1));
 132         printf("*%o->%o\t%s\t%s->%s\t%s%s%c", mode1, mode2,
 133                S_ISDIR(mode1) ? "tree" : "blob",
 134                old_sha1_hex, sha1_to_hex(sha2), base, path1,
 135                line_termination);
 136         return 0;
 137 }
 138
 139 static int interesting(void *tree, unsigned long size, const char *base)
 140 {
 141         const char *path;
 142         unsigned mode;
 143         int i;
 144         int baselen, pathlen;
 145
 146         if (!nr_paths)
 147                 return 1;
 148
 149         (void)extract(tree, size, &path, &mode);
 150
 151         pathlen = strlen(path);
 152         baselen = strlen(base);
 153
 154         for (i=0; i < nr_paths; i++) {
 155                 const char *match = paths[i];
 156                 int matchlen = pathlens[i];
 157
 158                 if (baselen >= matchlen) {
 159                         /* If it doesn't match, move along... */
 160                         if (strncmp(base, match, matchlen))
 161                                 continue;
 162
 163                         /* The base is a subdirectory of a path which was specified. */
 164                         return 1;
 165                 }
 166
 167                 /* Does the base match? */
 168                 if (strncmp(base, match, baselen))
 169                         continue;
 170
 171                 match += baselen;
 172                 matchlen -= baselen;
 173
 174                 if (pathlen > matchlen)
 175                         continue;
 176
 177                 if (strncmp(path, match, pathlen))
 178                         continue;
 179
 180                 return 1;
 181         }
 182         return 0; /* No matches */
 183 }
 184
 185 static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
 186 {
 187         while (size1 | size2) {
 188                 if (nr_paths && size1 && !interesting(tree1, size1, base)) {
 189                         update_tree_entry(&tree1, &size1);
 190                         continue;
 191                 }
 192                 if (nr_paths && size2 && !interesting(tree2, size2, base)) {
 193                         update_tree_entry(&tree2, &size2);
 194                         continue;
 195                 }
 196                 if (!size1) {
 197                         show_file("+", tree2, size2, base);
 198                         update_tree_entry(&tree2, &size2);
 199                         continue;
 200                 }
 201                 if (!size2) {
 202                         show_file("-", tree1, size1, base);
 203                         update_tree_entry(&tree1, &size1);
 204                         continue;
 205                 }
 206                 switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
 207                 case -1:
 208                         update_tree_entry(&tree1, &size1);
 209                         continue;
 210                 case 0:
 211                         update_tree_entry(&tree1, &size1);
 212                         /* Fallthrough */
 213                 case 1:
 214                         update_tree_entry(&tree2, &size2);
 215                         continue;
 216                 }
 217                 die("diff-tree: internal error");
 218         }
 219         return 0;
 220 }
 221
 222 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
 223 {
 224         void *tree1, *tree2;
 225         unsigned long size1, size2;
 226         int retval;
 227
 228         tree1 = read_tree_with_tree_or_commit_sha1(old, &size1, 0);
 229         if (!tree1)
 230                 die("unable to read source tree (%s)", sha1_to_hex(old));
 231         tree2 = read_tree_with_tree_or_commit_sha1(new, &size2, 0);
 232         if (!tree2)
 233                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 234         retval = diff_tree(tree1, size1, tree2, size2, base);
 235         free(tree1);
 236         free(tree2);
 237         return retval;
 238 }
 239
 240 static char *diff_tree_usage = "diff-tree [-r] [-z] <tree sha1> <tree sha1>";
 241
 242 int main(int argc, char **argv)
 243 {
 244         unsigned char old[20], new[20];
 245
 246         for (;;) {
 247                 char *arg = argv[1];
 248
 249                 if (!arg || *arg != '-')
 250                         break;
 251
 252                 argv++;
 253                 argc--;
 254                 if (!strcmp(arg, "-r")) {
 255                         recursive = 1;
 256                         continue;
 257                 }
 258                 if (!strcmp(arg, "-z")) {
 259                         line_termination = '\0';
 260                         continue;
 261                 }
 262                 usage(diff_tree_usage);
 263         }
 264
 265         if (argc < 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
 266                 usage(diff_tree_usage);
 267
 268         if (argc > 3) {
 269                 int i;
 270
 271                 paths = &argv[3];
 272                 nr_paths = argc - 3;
 273                 pathlens = malloc(nr_paths * sizeof(int));
 274                 for (i=0; i<nr_paths; i++)
 275                         pathlens[i] = strlen(paths[i]);
 276         }
 277
 278         return diff_tree_sha1(old, new, "");
 279 }