tree-diff.c

   1 /*
   2  * Helper functions for tree diff generation
   3  */
   4 #include "cache.h"
   5 #include "diff.h"
   6 #include "tree.h"
   7
   8 static char *malloc_base(const char *base, int baselen, const char *path, int pathlen)
   9 {
  10         char *newbase = xmalloc(baselen + pathlen + 2);
  11         memcpy(newbase, base, baselen);
  12         memcpy(newbase + baselen, path, pathlen);
  13         memcpy(newbase + baselen + pathlen, "/", 2);
  14         return newbase;
  15 }
  16
  17 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
  18                        const char *base, int baselen);
  19
  20 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
  21 {
  22         unsigned mode1, mode2;
  23         const char *path1, *path2;
  24         const unsigned char *sha1, *sha2;
  25         int cmp, pathlen1, pathlen2;
  26
  27         sha1 = tree_entry_extract(t1, &path1, &mode1);
  28         sha2 = tree_entry_extract(t2, &path2, &mode2);
  29
  30         pathlen1 = tree_entry_len(path1, sha1);
  31         pathlen2 = tree_entry_len(path2, sha2);
  32         cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
  33         if (cmp < 0) {
  34                 show_entry(opt, "-", t1, base, baselen);
  35                 return -1;
  36         }
  37         if (cmp > 0) {
  38                 show_entry(opt, "+", t2, base, baselen);
  39                 return 1;
  40         }
  41         if (!opt->find_copies_harder && !hashcmp(sha1, sha2) && mode1 == mode2)
  42                 return 0;
  43
  44         /*
  45          * If the filemode has changed to/from a directory from/to a regular
  46          * file, we need to consider it a remove and an add.
  47          */
  48         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
  49                 show_entry(opt, "-", t1, base, baselen);
  50                 show_entry(opt, "+", t2, base, baselen);
  51                 return 0;
  52         }
  53
  54         if (opt->recursive && S_ISDIR(mode1)) {
  55                 int retval;
  56                 char *newbase = malloc_base(base, baselen, path1, pathlen1);
  57                 if (opt->tree_in_recursive)
  58                         opt->change(opt, mode1, mode2,
  59                                     sha1, sha2, base, path1);
  60                 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
  61                 free(newbase);
  62                 return retval;
  63         }
  64
  65         opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
  66         return 0;
  67 }
  68
  69 /*
  70  * Is a tree entry interesting given the pathspec we have?
  71  *
  72  * Return:
  73  *  - positive for yes
  74  *  - zero for no
  75  *  - negative for "no, and no subsequent entries will be either"
  76  */
  77 static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
  78 {
  79         const char *path;
  80         const unsigned char *sha1;
  81         unsigned mode;
  82         int i;
  83         int pathlen;
  84
  85         if (!opt->nr_paths)
  86                 return 1;
  87
  88         sha1 = tree_entry_extract(desc, &path, &mode);
  89
  90         pathlen = tree_entry_len(path, sha1);
  91
  92         for (i=0; i < opt->nr_paths; i++) {
  93                 const char *match = opt->paths[i];
  94                 int matchlen = opt->pathlens[i];
  95
  96                 if (baselen >= matchlen) {
  97                         /* If it doesn't match, move along... */
  98                         if (strncmp(base, match, matchlen))
  99                                 continue;
 100
 101                         /* The base is a subdirectory of a path which was specified. */
 102                         return 1;
 103                 }
 104
 105                 /* Does the base match? */
 106                 if (strncmp(base, match, baselen))
 107                         continue;
 108
 109                 match += baselen;
 110                 matchlen -= baselen;
 111
 112                 if (pathlen > matchlen)
 113                         continue;
 114
 115                 if (matchlen > pathlen) {
 116                         if (match[pathlen] != '/')
 117                                 continue;
 118                         if (!S_ISDIR(mode))
 119                                 continue;
 120                 }
 121
 122                 if (strncmp(path, match, pathlen))
 123                         continue;
 124
 125                 return 1;
 126         }
 127         return 0; /* No matches */
 128 }
 129
 130 /* A whole sub-tree went away or appeared */
 131 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
 132 {
 133         while (desc->size) {
 134                 int show = tree_entry_interesting(desc, base, baselen, opt);
 135                 if (show < 0)
 136                         break;
 137                 if (show)
 138                         show_entry(opt, prefix, desc, base, baselen);
 139                 update_tree_entry(desc);
 140         }
 141 }
 142
 143 /* A file entry went away or appeared */
 144 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
 145                        const char *base, int baselen)
 146 {
 147         unsigned mode;
 148         const char *path;
 149         const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
 150
 151         if (opt->recursive && S_ISDIR(mode)) {
 152                 enum object_type type;
 153                 int pathlen = tree_entry_len(path, sha1);
 154                 char *newbase = malloc_base(base, baselen, path, pathlen);
 155                 struct tree_desc inner;
 156                 void *tree;
 157
 158                 tree = read_sha1_file(sha1, &type, &inner.size);
 159                 if (!tree || type != OBJ_TREE)
 160                         die("corrupt tree sha %s", sha1_to_hex(sha1));
 161
 162                 inner.buf = tree;
 163                 show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
 164
 165                 free(tree);
 166                 free(newbase);
 167         } else {
 168                 opt->add_remove(opt, prefix[0], mode, sha1, base, path);
 169         }
 170 }
 171
 172 static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
 173 {
 174         while (t->size) {
 175                 int show = tree_entry_interesting(t, base, baselen, opt);
 176                 if (!show) {
 177                         update_tree_entry(t);
 178                         continue;
 179                 }
 180                 /* Skip it all? */
 181                 if (show < 0)
 182                         t->size = 0;
 183                 return;
 184         }
 185 }
 186
 187 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 188 {
 189         int baselen = strlen(base);
 190
 191         for (;;) {
 192                 if (opt->quiet && opt->has_changes)
 193                         break;
 194                 if (opt->nr_paths) {
 195                         skip_uninteresting(t1, base, baselen, opt);
 196                         skip_uninteresting(t2, base, baselen, opt);
 197                 }
 198                 if (!t1->size) {
 199                         if (!t2->size)
 200                                 break;
 201                         show_entry(opt, "+", t2, base, baselen);
 202                         update_tree_entry(t2);
 203                         continue;
 204                 }
 205                 if (!t2->size) {
 206                         show_entry(opt, "-", t1, base, baselen);
 207                         update_tree_entry(t1);
 208                         continue;
 209                 }
 210                 switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
 211                 case -1:
 212                         update_tree_entry(t1);
 213                         continue;
 214                 case 0:
 215                         update_tree_entry(t1);
 216                         /* Fallthrough */
 217                 case 1:
 218                         update_tree_entry(t2);
 219                         continue;
 220                 }
 221                 die("git-diff-tree: internal error");
 222         }
 223         return 0;
 224 }
 225
 226 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
 227 {
 228         void *tree1, *tree2;
 229         struct tree_desc t1, t2;
 230         int retval;
 231
 232         tree1 = read_object_with_reference(old, tree_type, &t1.size, NULL);
 233         if (!tree1)
 234                 die("unable to read source tree (%s)", sha1_to_hex(old));
 235         tree2 = read_object_with_reference(new, tree_type, &t2.size, NULL);
 236         if (!tree2)
 237                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 238         t1.buf = tree1;
 239         t2.buf = tree2;
 240         retval = diff_tree(&t1, &t2, base, opt);
 241         free(tree1);
 242         free(tree2);
 243         return retval;
 244 }
 245
 246 int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
 247 {
 248         int retval;
 249         void *tree;
 250         struct tree_desc empty, real;
 251
 252         tree = read_object_with_reference(new, tree_type, &real.size, NULL);
 253         if (!tree)
 254                 die("unable to read root tree (%s)", sha1_to_hex(new));
 255         real.buf = tree;
 256
 257         empty.size = 0;
 258         empty.buf = "";
 259         retval = diff_tree(&empty, &real, base, opt);
 260         free(tree);
 261         return retval;
 262 }
 263
 264 static int count_paths(const char **paths)
 265 {
 266         int i = 0;
 267         while (*paths++)
 268                 i++;
 269         return i;
 270 }
 271
 272 void diff_tree_release_paths(struct diff_options *opt)
 273 {
 274         free(opt->pathlens);
 275 }
 276
 277 void diff_tree_setup_paths(const char **p, struct diff_options *opt)
 278 {
 279         opt->nr_paths = 0;
 280         opt->pathlens = NULL;
 281         opt->paths = NULL;
 282
 283         if (p) {
 284                 int i;
 285
 286                 opt->paths = p;
 287                 opt->nr_paths = count_paths(p);
 288                 if (opt->nr_paths == 0) {
 289                         opt->pathlens = NULL;
 290                         return;
 291                 }
 292                 opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
 293                 for (i=0; i < opt->nr_paths; i++)
 294                         opt->pathlens[i] = strlen(p[i]);
 295         }
 296 }