diff-tree.c

   1 #include "cache.h"
   2
   3 static int recursive = 0;
   4 static int line_termination = '\n';
   5
   6 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base);
   7
   8 static void update_tree_entry(void **bufp, unsigned long *sizep)
   9 {
  10         void *buf = *bufp;
  11         unsigned long size = *sizep;
  12         int len = strlen(buf) + 1 + 20;
  13
  14         if (size < len)
  15                 die("corrupt tree file");
  16         *bufp = buf + len;
  17         *sizep = size - len;
  18 }
  19
  20 static const unsigned char *extract(void *tree, unsigned long size, const char **pathp, unsigned int *modep)
  21 {
  22         int len = strlen(tree)+1;
  23         const unsigned char *sha1 = tree + len;
  24         const char *path = strchr(tree, ' ');
  25
  26         if (!path || size < len + 20 || sscanf(tree, "%o", modep) != 1)
  27                 die("corrupt tree file");
  28         *pathp = path+1;
  29         return sha1;
  30 }
  31
  32 static char *malloc_base(const char *base, const char *path, int pathlen)
  33 {
  34         int baselen = strlen(base);
  35         char *newbase = malloc(baselen + pathlen + 2);
  36         memcpy(newbase, base, baselen);
  37         memcpy(newbase + baselen, path, pathlen);
  38         memcpy(newbase + baselen + pathlen, "/", 2);
  39         return newbase;
  40 }
  41
  42 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base);
  43
  44 /* A whole sub-tree went away or appeared */
  45 static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base)
  46 {
  47         while (size) {
  48                 show_file(prefix, tree, size, base);
  49                 update_tree_entry(&tree, &size);
  50         }
  51 }
  52
  53 /* A file entry went away or appeared */
  54 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base)
  55 {
  56         unsigned mode;
  57         const char *path;
  58         const unsigned char *sha1 = extract(tree, size, &path, &mode);
  59
  60         if (recursive && S_ISDIR(mode)) {
  61                 char type[20];
  62                 unsigned long size;
  63                 char *newbase = malloc_base(base, path, strlen(path));
  64                 void *tree;
  65
  66                 tree = read_sha1_file(sha1, type, &size);
  67                 if (!tree || strcmp(type, "tree"))
  68                         die("corrupt tree sha %s", sha1_to_hex(sha1));
  69
  70                 show_tree(prefix, tree, size, newbase);
  71
  72                 free(tree);
  73                 free(newbase);
  74                 return;
  75         }
  76
  77         printf("%s%o\t%s\t%s\t%s%s%c", prefix, mode,
  78                S_ISDIR(mode) ? "tree" : "blob",
  79                sha1_to_hex(sha1), base, path,
  80                line_termination);
  81 }
  82
  83 static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
  84 {
  85         unsigned mode1, mode2;
  86         const char *path1, *path2;
  87         const unsigned char *sha1, *sha2;
  88         int cmp, pathlen1, pathlen2;
  89         char old_sha1_hex[50];
  90
  91         sha1 = extract(tree1, size1, &path1, &mode1);
  92         sha2 = extract(tree2, size2, &path2, &mode2);
  93
  94         pathlen1 = strlen(path1);
  95         pathlen2 = strlen(path2);
  96         cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
  97         if (cmp < 0) {
  98                 show_file("-", tree1, size1, base);
  99                 return -1;
 100         }
 101         if (cmp > 0) {
 102                 show_file("+", tree2, size2, base);
 103                 return 1;
 104         }
 105         if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
 106                 return 0;
 107
 108         /*
 109          * If the filemode has changed to/from a directory from/to a regular
 110          * file, we need to consider it a remove and an add.
 111          */
 112         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
 113                 show_file("-", tree1, size1, base);
 114                 show_file("+", tree2, size2, base);
 115                 return 0;
 116         }
 117
 118         if (recursive && S_ISDIR(mode1)) {
 119                 int retval;
 120                 char *newbase = malloc_base(base, path1, pathlen1);
 121                 retval = diff_tree_sha1(sha1, sha2, newbase);
 122                 free(newbase);
 123                 return retval;
 124         }
 125
 126         strcpy(old_sha1_hex, sha1_to_hex(sha1));
 127         printf("*%o->%o\t%s\t%s->%s\t%s%s%c", mode1, mode2,
 128                S_ISDIR(mode1) ? "tree" : "blob",
 129                old_sha1_hex, sha1_to_hex(sha2), base, path1,
 130                line_termination);
 131         return 0;
 132 }
 133
 134 static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
 135 {
 136         while (size1 | size2) {
 137                 if (!size1) {
 138                         show_file("+", tree2, size2, base);
 139                         update_tree_entry(&tree2, &size2);
 140                         continue;
 141                 }
 142                 if (!size2) {
 143                         show_file("-", tree1, size1, base);
 144                         update_tree_entry(&tree1, &size1);
 145                         continue;
 146                 }
 147                 switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
 148                 case -1:
 149                         update_tree_entry(&tree1, &size1);
 150                         continue;
 151                 case 0:
 152                         update_tree_entry(&tree1, &size1);
 153                         /* Fallthrough */
 154                 case 1:
 155                         update_tree_entry(&tree2, &size2);
 156                         continue;
 157                 }
 158                 die("diff-tree: internal error");
 159         }
 160         return 0;
 161 }
 162
 163 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
 164 {
 165         void *tree1, *tree2;
 166         unsigned long size1, size2;
 167         char type[20];
 168         int retval;
 169
 170         tree1 = read_sha1_file(old, type, &size1);
 171         if (!tree1 || strcmp(type, "tree"))
 172                 die("unable to read source tree (%s)", sha1_to_hex(old));
 173         tree2 = read_sha1_file(new, type, &size2);
 174         if (!tree2 || strcmp(type, "tree"))
 175                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 176         retval = diff_tree(tree1, size1, tree2, size2, base);
 177         free(tree1);
 178         free(tree2);
 179         return retval;
 180 }
 181
 182 int main(int argc, char **argv)
 183 {
 184         unsigned char old[20], new[20];
 185
 186         while (argc > 3) {
 187                 char *arg = argv[1];
 188                 argv++;
 189                 argc--;
 190                 if (!strcmp(arg, "-r")) {
 191                         recursive = 1;
 192                         continue;
 193                 }
 194                 if (!strcmp(arg, "-z")) {
 195                         line_termination = '\0';
 196                         continue;
 197                 }
 198                 usage("diff-tree [-r] [-z] <tree sha1> <tree sha1>");
 199         }
 200
 201         if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
 202                 usage("diff-tree <tree sha1> <tree sha1>");
 203         return diff_tree_sha1(old, new, "");
 204 }