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                 die("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                 die("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                         die("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\t%s\t%s\t%s%s%c", prefix, mode,
  77                S_ISDIR(mode) ? "tree" : "blob",
  78                sha1_to_hex(sha1), base, path, 0);
  79 }
  80
  81 static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
  82 {
  83         unsigned mode1, mode2;
  84         const char *path1, *path2;
  85         const unsigned char *sha1, *sha2;
  86         int cmp, pathlen1, pathlen2;
  87         char old_sha1_hex[50];
  88
  89         sha1 = extract(tree1, size1, &path1, &mode1);
  90         sha2 = extract(tree2, size2, &path2, &mode2);
  91
  92         pathlen1 = strlen(path1);
  93         pathlen2 = strlen(path2);
  94         cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
  95         if (cmp < 0) {
  96                 show_file("-", tree1, size1, base);
  97                 return -1;
  98         }
  99         if (cmp > 0) {
 100                 show_file("+", tree2, size2, base);
 101                 return 1;
 102         }
 103         if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
 104                 return 0;
 105
 106         /*
 107          * If the filemode has changed to/from a directory from/to a regular
 108          * file, we need to consider it a remove and an add.
 109          */
 110         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
 111                 show_file("-", tree1, size1, base);
 112                 show_file("+", tree2, size2, base);
 113                 return 0;
 114         }
 115
 116         if (recursive && S_ISDIR(mode1)) {
 117                 int retval;
 118                 char *newbase = malloc_base(base, path1, pathlen1);
 119                 retval = diff_tree_sha1(sha1, sha2, newbase);
 120                 free(newbase);
 121                 return retval;
 122         }
 123
 124         strcpy(old_sha1_hex, sha1_to_hex(sha1));
 125         printf("*%o->%o\t%s\t%s->%s\t%s%s%c", mode1, mode2,
 126                S_ISDIR(mode1) ? "tree" : "blob",
 127                old_sha1_hex, sha1_to_hex(sha2), base, path1, 0);
 128         return 0;
 129 }
 130
 131 static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
 132 {
 133         while (size1 | size2) {
 134                 if (!size1) {
 135                         show_file("+", tree2, size2, base);
 136                         update_tree_entry(&tree2, &size2);
 137                         continue;
 138                 }
 139                 if (!size2) {
 140                         show_file("-", tree1, size1, base);
 141                         update_tree_entry(&tree1, &size1);
 142                         continue;
 143                 }
 144                 switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
 145                 case -1:
 146                         update_tree_entry(&tree1, &size1);
 147                         continue;
 148                 case 0:
 149                         update_tree_entry(&tree1, &size1);
 150                         /* Fallthrough */
 151                 case 1:
 152                         update_tree_entry(&tree2, &size2);
 153                         continue;
 154                 }
 155                 die("diff-tree: internal error");
 156         }
 157         return 0;
 158 }
 159
 160 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
 161 {
 162         void *tree1, *tree2;
 163         unsigned long size1, size2;
 164         char type[20];
 165         int retval;
 166
 167         tree1 = read_sha1_file(old, type, &size1);
 168         if (!tree1 || strcmp(type, "tree"))
 169                 die("unable to read source tree (%s)", sha1_to_hex(old));
 170         tree2 = read_sha1_file(new, type, &size2);
 171         if (!tree2 || strcmp(type, "tree"))
 172                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 173         retval = diff_tree(tree1, size1, tree2, size2, base);
 174         free(tree1);
 175         free(tree2);
 176         return retval;
 177 }
 178
 179 int main(int argc, char **argv)
 180 {
 181         unsigned char old[20], new[20];
 182
 183         while (argc > 3) {
 184                 char *arg = argv[1];
 185                 argv++;
 186                 argc--;
 187                 if (!strcmp(arg, "-r")) {
 188                         recursive = 1;
 189                         continue;
 190                 }
 191                 usage("diff-tree [-r] <tree sha1> <tree sha1>");
 192         }
 193
 194         if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
 195                 usage("diff-tree <tree sha1> <tree sha1>");
 196         return diff_tree_sha1(old, new, "");
 197 }