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 static int interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
  70 {
  71         const char *path;
  72         const unsigned char *sha1;
  73         unsigned mode;
  74         int i;
  75         int pathlen;
  76
  77         if (!opt->nr_paths)
  78                 return 1;
  79
  80         sha1 = tree_entry_extract(desc, &path, &mode);
  81
  82         pathlen = tree_entry_len(path, sha1);
  83
  84         for (i=0; i < opt->nr_paths; i++) {
  85                 const char *match = opt->paths[i];
  86                 int matchlen = opt->pathlens[i];
  87
  88                 if (baselen >= matchlen) {
  89                         /* If it doesn't match, move along... */
  90                         if (strncmp(base, match, matchlen))
  91                                 continue;
  92
  93                         /* The base is a subdirectory of a path which was specified. */
  94                         return 1;
  95                 }
  96
  97                 /* Does the base match? */
  98                 if (strncmp(base, match, baselen))
  99                         continue;
 100
 101                 match += baselen;
 102                 matchlen -= baselen;
 103
 104                 if (pathlen > matchlen)
 105                         continue;
 106
 107                 if (matchlen > pathlen) {
 108                         if (match[pathlen] != '/')
 109                                 continue;
 110                         if (!S_ISDIR(mode))
 111                                 continue;
 112                 }
 113
 114                 if (strncmp(path, match, pathlen))
 115                         continue;
 116
 117                 return 1;
 118         }
 119         return 0; /* No matches */
 120 }
 121
 122 /* A whole sub-tree went away or appeared */
 123 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
 124 {
 125         while (desc->size) {
 126                 if (interesting(desc, base, baselen, opt))
 127                         show_entry(opt, prefix, desc, base, baselen);
 128                 update_tree_entry(desc);
 129         }
 130 }
 131
 132 /* A file entry went away or appeared */
 133 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
 134                        const char *base, int baselen)
 135 {
 136         unsigned mode;
 137         const char *path;
 138         const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
 139
 140         if (opt->recursive && S_ISDIR(mode)) {
 141                 enum object_type type;
 142                 int pathlen = tree_entry_len(path, sha1);
 143                 char *newbase = malloc_base(base, baselen, path, pathlen);
 144                 struct tree_desc inner;
 145                 void *tree;
 146
 147                 tree = read_sha1_file(sha1, &type, &inner.size);
 148                 if (!tree || type != OBJ_TREE)
 149                         die("corrupt tree sha %s", sha1_to_hex(sha1));
 150
 151                 inner.buf = tree;
 152                 show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
 153
 154                 free(tree);
 155                 free(newbase);
 156         } else {
 157                 opt->add_remove(opt, prefix[0], mode, sha1, base, path);
 158         }
 159 }
 160
 161 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 162 {
 163         int baselen = strlen(base);
 164
 165         while (t1->size | t2->size) {
 166                 if (opt->quiet && opt->has_changes)
 167                         break;
 168                 if (opt->nr_paths && t1->size && !interesting(t1, base, baselen, opt)) {
 169                         update_tree_entry(t1);
 170                         continue;
 171                 }
 172                 if (opt->nr_paths && t2->size && !interesting(t2, base, baselen, opt)) {
 173                         update_tree_entry(t2);
 174                         continue;
 175                 }
 176                 if (!t1->size) {
 177                         show_entry(opt, "+", t2, base, baselen);
 178                         update_tree_entry(t2);
 179                         continue;
 180                 }
 181                 if (!t2->size) {
 182                         show_entry(opt, "-", t1, base, baselen);
 183                         update_tree_entry(t1);
 184                         continue;
 185                 }
 186                 switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
 187                 case -1:
 188                         update_tree_entry(t1);
 189                         continue;
 190                 case 0:
 191                         update_tree_entry(t1);
 192                         /* Fallthrough */
 193                 case 1:
 194                         update_tree_entry(t2);
 195                         continue;
 196                 }
 197                 die("git-diff-tree: internal error");
 198         }
 199         return 0;
 200 }
 201
 202 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
 203 {
 204         void *tree1, *tree2;
 205         struct tree_desc t1, t2;
 206         int retval;
 207
 208         tree1 = read_object_with_reference(old, tree_type, &t1.size, NULL);
 209         if (!tree1)
 210                 die("unable to read source tree (%s)", sha1_to_hex(old));
 211         tree2 = read_object_with_reference(new, tree_type, &t2.size, NULL);
 212         if (!tree2)
 213                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 214         t1.buf = tree1;
 215         t2.buf = tree2;
 216         retval = diff_tree(&t1, &t2, base, opt);
 217         free(tree1);
 218         free(tree2);
 219         return retval;
 220 }
 221
 222 int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
 223 {
 224         int retval;
 225         void *tree;
 226         struct tree_desc empty, real;
 227
 228         tree = read_object_with_reference(new, tree_type, &real.size, NULL);
 229         if (!tree)
 230                 die("unable to read root tree (%s)", sha1_to_hex(new));
 231         real.buf = tree;
 232
 233         empty.size = 0;
 234         empty.buf = "";
 235         retval = diff_tree(&empty, &real, base, opt);
 236         free(tree);
 237         return retval;
 238 }
 239
 240 static int count_paths(const char **paths)
 241 {
 242         int i = 0;
 243         while (*paths++)
 244                 i++;
 245         return i;
 246 }
 247
 248 void diff_tree_release_paths(struct diff_options *opt)
 249 {
 250         free(opt->pathlens);
 251 }
 252
 253 void diff_tree_setup_paths(const char **p, struct diff_options *opt)
 254 {
 255         opt->nr_paths = 0;
 256         opt->pathlens = NULL;
 257         opt->paths = NULL;
 258
 259         if (p) {
 260                 int i;
 261
 262                 opt->paths = p;
 263                 opt->nr_paths = count_paths(p);
 264                 if (opt->nr_paths == 0) {
 265                         opt->pathlens = NULL;
 266                         return;
 267                 }
 268                 opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
 269                 for (i=0; i < opt->nr_paths; i++)
 270                         opt->pathlens[i] = strlen(p[i]);
 271         }
 272 }