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 *src, const char *dst);
   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 void show_file(const char *prefix, void *tree, unsigned long size, const char *base)
  32 {
  33         unsigned mode;
  34         const char *path;
  35         const unsigned char *sha1 = extract(tree, size, &path, &mode);
  36         printf("%s%o %s %s%s%c", prefix, mode, sha1_to_hex(sha1), base, path, 0);
  37 }
  38
  39 static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *src, const char *dst)
  40 {
  41         unsigned mode1, mode2;
  42         const char *path1, *path2;
  43         const unsigned char *sha1, *sha2;
  44         int cmp, pathlen1, pathlen2;
  45
  46         sha1 = extract(tree1, size1, &path1, &mode1);
  47         sha2 = extract(tree2, size2, &path2, &mode2);
  48
  49         pathlen1 = strlen(path1);
  50         pathlen2 = strlen(path2);
  51         cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
  52         if (cmp < 0) {
  53                 show_file("-", tree1, size1, src);
  54                 return -1;
  55         }
  56         if (cmp > 0) {
  57                 show_file("+", tree2, size2, dst);
  58                 return 1;
  59         }
  60         if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
  61                 return 0;
  62         if (recursive && S_ISDIR(mode1) && S_ISDIR(mode2)) {
  63                 int srclen = strlen(src);
  64                 int dstlen = strlen(dst);
  65                 char *srcbase = malloc(srclen + pathlen1 + 2);
  66                 char *dstbase = malloc(srclen + pathlen1 + 2);
  67                 memcpy(srcbase, src, srclen);
  68                 memcpy(srcbase + srclen, path1, pathlen1);
  69                 memcpy(srcbase + srclen + pathlen1, "/", 2);
  70                 memcpy(dstbase, dst, dstlen);
  71                 memcpy(dstbase + dstlen, path2, pathlen2);
  72                 memcpy(dstbase + dstlen + pathlen2, "/", 2);
  73                 return diff_tree_sha1(sha1, sha2, srcbase, dstbase);
  74         }
  75
  76         show_file("<", tree1, size1, src);
  77         show_file(">", tree2, size2, dst);
  78         return 0;
  79 }
  80
  81 static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *src, const char *dst)
  82 {
  83         while (size1 | size2) {
  84                 if (!size1) {
  85                         show_file("+", tree2, size2, dst);
  86                         update_tree_entry(&tree2, &size2);
  87                         continue;
  88                 }
  89                 if (!size2) {
  90                         show_file("-", tree1, size1, src);
  91                         update_tree_entry(&tree1, &size1);
  92                         continue;
  93                 }
  94                 switch (compare_tree_entry(tree1, size1, tree2, size2, src, dst)) {
  95                 case -1:
  96                         update_tree_entry(&tree1, &size1);
  97                         continue;
  98                 case 0:
  99                         update_tree_entry(&tree1, &size1);
 100                         /* Fallthrough */
 101                 case 1:
 102                         update_tree_entry(&tree2, &size2);
 103                         continue;
 104                 }
 105                 usage("diff-tree: internal error");
 106         }
 107         return 0;
 108 }
 109
 110 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *src, const char *dst)
 111 {
 112         void *tree1, *tree2;
 113         unsigned long size1, size2;
 114         char type[20];
 115         int retval;
 116
 117         tree1 = read_sha1_file(old, type, &size1);
 118         if (!tree1 || strcmp(type, "tree"))
 119                 usage("unable to read source tree");
 120         tree2 = read_sha1_file(new, type, &size2);
 121         if (!tree2 || strcmp(type, "tree"))
 122                 usage("unable to read destination tree");
 123         retval = diff_tree(tree1, size1, tree2, size2, src, dst);
 124         free(tree1);
 125         free(tree2);
 126         return retval;
 127 }
 128
 129 int main(int argc, char **argv)
 130 {
 131         unsigned char old[20], new[20];
 132
 133         while (argc > 3) {
 134                 char *arg = argv[1];
 135                 argv++;
 136                 argc--;
 137                 if (!strcmp(arg, "-R")) {
 138                         recursive = 1;
 139                         continue;
 140                 }
 141                 usage("diff-tree [-R] <tree sha1> <tree sha1>");
 142         }
 143
 144         if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
 145                 usage("diff-tree <tree sha1> <tree sha1>");
 146         return diff_tree_sha1(old, new, "", "");
 147 }