tree-diff.c

   1 /*
   2  * Helper functions for tree diff generation
   3  */
   4 #include "cache.h"
   5 #include "diff.h"
   6
   7 // What paths are we interested in?
   8 static int nr_paths = 0;
   9 static const char **paths = NULL;
  10 static int *pathlens = NULL;
  11
  12 static char *malloc_base(const char *base, const char *path, int pathlen)
  13 {
  14         int baselen = strlen(base);
  15         char *newbase = xmalloc(baselen + pathlen + 2);
  16         memcpy(newbase, base, baselen);
  17         memcpy(newbase + baselen, path, pathlen);
  18         memcpy(newbase + baselen + pathlen, "/", 2);
  19         return newbase;
  20 }
  21
  22 static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base);
  23
  24 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
  25 {
  26         unsigned mode1, mode2;
  27         const char *path1, *path2;
  28         const unsigned char *sha1, *sha2;
  29         int cmp, pathlen1, pathlen2;
  30
  31         sha1 = tree_entry_extract(t1, &path1, &mode1);
  32         sha2 = tree_entry_extract(t2, &path2, &mode2);
  33
  34         pathlen1 = strlen(path1);
  35         pathlen2 = strlen(path2);
  36         cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
  37         if (cmp < 0) {
  38                 show_entry(opt, "-", t1, base);
  39                 return -1;
  40         }
  41         if (cmp > 0) {
  42                 show_entry(opt, "+", t2, base);
  43                 return 1;
  44         }
  45         if (!opt->find_copies_harder &&
  46             !memcmp(sha1, sha2, 20) && mode1 == mode2)
  47                 return 0;
  48
  49         /*
  50          * If the filemode has changed to/from a directory from/to a regular
  51          * file, we need to consider it a remove and an add.
  52          */
  53         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
  54                 show_entry(opt, "-", t1, base);
  55                 show_entry(opt, "+", t2, base);
  56                 return 0;
  57         }
  58
  59         if (opt->recursive && S_ISDIR(mode1)) {
  60                 int retval;
  61                 char *newbase = malloc_base(base, path1, pathlen1);
  62                 if (opt->tree_in_recursive)
  63                         opt->change(opt, mode1, mode2,
  64                                     sha1, sha2, base, path1);
  65                 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
  66                 free(newbase);
  67                 return retval;
  68         }
  69
  70         opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
  71         return 0;
  72 }
  73
  74 static int interesting(struct tree_desc *desc, const char *base)
  75 {
  76         const char *path;
  77         unsigned mode;
  78         int i;
  79         int baselen, pathlen;
  80
  81         if (!nr_paths)
  82                 return 1;
  83
  84         (void)tree_entry_extract(desc, &path, &mode);
  85
  86         pathlen = strlen(path);
  87         baselen = strlen(base);
  88
  89         for (i=0; i < nr_paths; i++) {
  90                 const char *match = paths[i];
  91                 int matchlen = pathlens[i];
  92
  93                 if (baselen >= matchlen) {
  94                         /* If it doesn't match, move along... */
  95                         if (strncmp(base, match, matchlen))
  96                                 continue;
  97
  98                         /* The base is a subdirectory of a path which was specified. */
  99                         return 1;
 100                 }
 101
 102                 /* Does the base match? */
 103                 if (strncmp(base, match, baselen))
 104                         continue;
 105
 106                 match += baselen;
 107                 matchlen -= baselen;
 108
 109                 if (pathlen > matchlen)
 110                         continue;
 111
 112                 if (matchlen > pathlen) {
 113                         if (match[pathlen] != '/')
 114                                 continue;
 115                         if (!S_ISDIR(mode))
 116                                 continue;
 117                 }
 118
 119                 if (strncmp(path, match, pathlen))
 120                         continue;
 121
 122                 return 1;
 123         }
 124         return 0; /* No matches */
 125 }
 126
 127 /* A whole sub-tree went away or appeared */
 128 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
 129 {
 130         while (desc->size) {
 131                 if (interesting(desc, base))
 132                         show_entry(opt, prefix, desc, base);
 133                 update_tree_entry(desc);
 134         }
 135 }
 136
 137 /* A file entry went away or appeared */
 138 static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
 139 {
 140         unsigned mode;
 141         const char *path;
 142         const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
 143
 144         if (opt->recursive && S_ISDIR(mode)) {
 145                 char type[20];
 146                 char *newbase = malloc_base(base, path, strlen(path));
 147                 struct tree_desc inner;
 148                 void *tree;
 149
 150                 tree = read_sha1_file(sha1, type, &inner.size);
 151                 if (!tree || strcmp(type, "tree"))
 152                         die("corrupt tree sha %s", sha1_to_hex(sha1));
 153
 154                 inner.buf = tree;
 155                 show_tree(opt, prefix, &inner, newbase);
 156
 157                 free(tree);
 158                 free(newbase);
 159                 return 0;
 160         }
 161
 162         opt->add_remove(opt, prefix[0], mode, sha1, base, path);
 163         return 0;
 164 }
 165
 166 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 167 {
 168         while (t1->size | t2->size) {
 169                 if (nr_paths && t1->size && !interesting(t1, base)) {
 170                         update_tree_entry(t1);
 171                         continue;
 172                 }
 173                 if (nr_paths && t2->size && !interesting(t2, base)) {
 174                         update_tree_entry(t2);
 175                         continue;
 176                 }
 177                 if (!t1->size) {
 178                         show_entry(opt, "+", t2, base);
 179                         update_tree_entry(t2);
 180                         continue;
 181                 }
 182                 if (!t2->size) {
 183                         show_entry(opt, "-", t1, base);
 184                         update_tree_entry(t1);
 185                         continue;
 186                 }
 187                 switch (compare_tree_entry(t1, t2, base, opt)) {
 188                 case -1:
 189                         update_tree_entry(t1);
 190                         continue;
 191                 case 0:
 192                         update_tree_entry(t1);
 193                         /* Fallthrough */
 194                 case 1:
 195                         update_tree_entry(t2);
 196                         continue;
 197                 }
 198                 die("git-diff-tree: internal error");
 199         }
 200         return 0;
 201 }
 202
 203 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
 204 {
 205         void *tree1, *tree2;
 206         struct tree_desc t1, t2;
 207         int retval;
 208
 209         tree1 = read_object_with_reference(old, "tree", &t1.size, NULL);
 210         if (!tree1)
 211                 die("unable to read source tree (%s)", sha1_to_hex(old));
 212         tree2 = read_object_with_reference(new, "tree", &t2.size, NULL);
 213         if (!tree2)
 214                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 215         t1.buf = tree1;
 216         t2.buf = tree2;
 217         retval = diff_tree(&t1, &t2, base, opt);
 218         free(tree1);
 219         free(tree2);
 220         return retval;
 221 }
 222
 223 static int count_paths(const char **paths)
 224 {
 225         int i = 0;
 226         while (*paths++)
 227                 i++;
 228         return i;
 229 }
 230
 231 void diff_tree_setup_paths(const char **p)
 232 {
 233         if (p) {
 234                 int i;
 235
 236                 paths = p;
 237                 nr_paths = count_paths(paths);
 238                 if (nr_paths == 0) {
 239                         pathlens = NULL;
 240                         return;
 241                 }
 242                 pathlens = xmalloc(nr_paths * sizeof(int));
 243                 for (i=0; i<nr_paths; i++)
 244                         pathlens[i] = strlen(paths[i]);
 245         }
 246 }