diff-tree.c

   1 #include "cache.h"
   2
   3 static int recursive = 0;
   4
   5 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base);
   6
   7 static void update_tree_entry(void **bufp, unsigned long *sizep)
   8 {
   9         void *buf = *bufp;
  10         unsigned long size = *sizep;
  11         int len = strlen(buf) + 1 + 20;
  12
  13         if (size < len)
  14                 usage("corrupt tree file");
  15         *bufp = buf + len;
  16         *sizep = size - len;
  17 }
  18
  19 static const unsigned char *extract(void *tree, unsigned long size, const char **pathp, unsigned int *modep)
  20 {
  21         int len = strlen(tree)+1;
  22         const unsigned char *sha1 = tree + len;
  23         const char *path = strchr(tree, ' ');
  24
  25         if (!path || size < len + 20 || sscanf(tree, "%o", modep) != 1)
  26                 usage("corrupt tree file");
  27         *pathp = path+1;
  28         return sha1;
  29 }
  30
  31 static char *malloc_base(const char *base, const char *path, int pathlen)
  32 {
  33         int baselen = strlen(base);
  34         char *newbase = malloc(baselen + pathlen + 2);
  35         memcpy(newbase, base, baselen);
  36         memcpy(newbase + baselen, path, pathlen);
  37         memcpy(newbase + baselen + pathlen, "/", 2);
  38         return newbase;
  39 }
  40
  41 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base);
  42
  43 /* A whole sub-tree went away or appeared */
  44 static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base)
  45 {
  46         while (size) {
  47                 show_file(prefix, tree, size, base);
  48                 update_tree_entry(&tree, &size);
  49         }
  50 }
  51
  52 /* A file entry went away or appeared */
  53 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base)
  54 {
  55         unsigned mode;
  56         const char *path;
  57         const unsigned char *sha1 = extract(tree, size, &path, &mode);
  58
  59         if (recursive && S_ISDIR(mode)) {
  60                 char type[20];
  61                 unsigned long size;
  62                 char *newbase = malloc_base(base, path, strlen(path));
  63                 void *tree;
  64
  65                 tree = read_sha1_file(sha1, type, &size);
  66                 if (!tree || strcmp(type, "tree"))
  67                         usage("corrupt tree sha %s", sha1_to_hex(sha1));
  68
  69                 show_tree(prefix, tree, size, newbase);
  70
  71                 free(tree);
  72                 free(newbase);
  73                 return;
  74         }
  75
  76         printf("%s%o %s %s%s%c", prefix, mode, sha1_to_hex(sha1), base, path, 0);
  77 }
  78
  79 static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
  80 {
  81         unsigned mode1, mode2;
  82         const char *path1, *path2;
  83         const unsigned char *sha1, *sha2;
  84         int cmp, pathlen1, pathlen2;
  85         char old_sha1_hex[50];
  86
  87         sha1 = extract(tree1, size1, &path1, &mode1);
  88         sha2 = extract(tree2, size2, &path2, &mode2);
  89
  90         pathlen1 = strlen(path1);
  91         pathlen2 = strlen(path2);
  92         cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
  93         if (cmp < 0) {
  94                 show_file("-", tree1, size1, base);
  95                 return -1;
  96         }
  97         if (cmp > 0) {
  98                 show_file("+", tree2, size2, base);
  99                 return 1;
 100         }
 101         if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
 102                 return 0;
 103
 104         /*
 105          * If the filemode has changed to/from a directory from/to a regular
 106          * file, we need to consider it a remove and an add.
 107          */
 108         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
 109                 show_file("-", tree1, size1, base);
 110                 show_file("+", tree2, size2, base);
 111                 return 0;
 112         }
 113
 114         if (recursive && S_ISDIR(mode1)) {
 115                 int retval;
 116                 char *newbase = malloc_base(base, path1, pathlen1);
 117                 retval = diff_tree_sha1(sha1, sha2, newbase);
 118                 free(newbase);
 119                 return retval;
 120         }
 121
 122         strcpy(old_sha1_hex, sha1_to_hex(sha1));
 123         printf("*%o->%o %s->%s %s%s%c", mode1, mode2, old_sha1_hex, sha1_to_hex(sha2), base, path1, 0);
 124         return 0;
 125 }
 126
 127 static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
 128 {
 129         while (size1 | size2) {
 130                 if (!size1) {
 131                         show_file("+", tree2, size2, base);
 132                         update_tree_entry(&tree2, &size2);
 133                         continue;
 134                 }
 135                 if (!size2) {
 136                         show_file("-", tree1, size1, base);
 137                         update_tree_entry(&tree1, &size1);
 138                         continue;
 139                 }
 140                 switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
 141                 case -1:
 142                         update_tree_entry(&tree1, &size1);
 143                         continue;
 144                 case 0:
 145                         update_tree_entry(&tree1, &size1);
 146                         /* Fallthrough */
 147                 case 1:
 148                         update_tree_entry(&tree2, &size2);
 149                         continue;
 150                 }
 151                 usage("diff-tree: internal error");
 152         }
 153         return 0;
 154 }
 155
 156 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
 157 {
 158         void *tree1, *tree2;
 159         unsigned long size1, size2;
 160         char type[20];
 161         int retval;
 162
 163         tree1 = read_sha1_file(old, type, &size1);
 164         if (!tree1 || strcmp(type, "tree"))
 165                 usage("unable to read source tree");
 166         tree2 = read_sha1_file(new, type, &size2);
 167         if (!tree2 || strcmp(type, "tree"))
 168                 usage("unable to read destination tree");
 169         retval = diff_tree(tree1, size1, tree2, size2, base);
 170         free(tree1);
 171         free(tree2);
 172         return retval;
 173 }
 174
 175 int main(int argc, char **argv)
 176 {
 177         unsigned char old[20], new[20];
 178
 179         while (argc > 3) {
 180                 char *arg = argv[1];
 181                 argv++;
 182                 argc--;
 183                 if (!strcmp(arg, "-r")) {
 184                         recursive = 1;
 185                         continue;
 186                 }
 187                 usage("diff-tree [-R] <tree sha1> <tree sha1>");
 188         }
 189
 190         if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
 191                 usage("diff-tree <tree sha1> <tree sha1>");
 192         return diff_tree_sha1(old, new, "");
 193 }