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 // What paths are we interested in?
   9 static int nr_paths = 0;
  10 static const char **paths = NULL;
  11 static int *pathlens = NULL;
  12
  13 static char *malloc_base(const char *base, const char *path, int pathlen)
  14 {
  15         int baselen = strlen(base);
  16         char *newbase = xmalloc(baselen + pathlen + 2);
  17         memcpy(newbase, base, baselen);
  18         memcpy(newbase + baselen, path, pathlen);
  19         memcpy(newbase + baselen + pathlen, "/", 2);
  20         return newbase;
  21 }
  22
  23 static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base);
  24
  25 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
  26 {
  27         unsigned mode1, mode2;
  28         const char *path1, *path2;
  29         const unsigned char *sha1, *sha2;
  30         int cmp, pathlen1, pathlen2;
  31
  32         sha1 = tree_entry_extract(t1, &path1, &mode1);
  33         sha2 = tree_entry_extract(t2, &path2, &mode2);
  34
  35         pathlen1 = strlen(path1);
  36         pathlen2 = strlen(path2);
  37         cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
  38         if (cmp < 0) {
  39                 show_entry(opt, "-", t1, base);
  40                 return -1;
  41         }
  42         if (cmp > 0) {
  43                 show_entry(opt, "+", t2, base);
  44                 return 1;
  45         }
  46         if (!opt->find_copies_harder &&
  47             !memcmp(sha1, sha2, 20) && mode1 == mode2)
  48                 return 0;
  49
  50         /*
  51          * If the filemode has changed to/from a directory from/to a regular
  52          * file, we need to consider it a remove and an add.
  53          */
  54         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
  55                 show_entry(opt, "-", t1, base);
  56                 show_entry(opt, "+", t2, base);
  57                 return 0;
  58         }
  59
  60         if (opt->recursive && S_ISDIR(mode1)) {
  61                 int retval;
  62                 char *newbase = malloc_base(base, path1, pathlen1);
  63                 if (opt->tree_in_recursive)
  64                         opt->change(opt, mode1, mode2,
  65                                     sha1, sha2, base, path1);
  66                 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
  67                 free(newbase);
  68                 return retval;
  69         }
  70
  71         opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
  72         return 0;
  73 }
  74
  75 static int interesting(struct tree_desc *desc, const char *base)
  76 {
  77         const char *path;
  78         unsigned mode;
  79         int i;
  80         int baselen, pathlen;
  81
  82         if (!nr_paths)
  83                 return 1;
  84
  85         (void)tree_entry_extract(desc, &path, &mode);
  86
  87         pathlen = strlen(path);
  88         baselen = strlen(base);
  89
  90         for (i=0; i < nr_paths; i++) {
  91                 const char *match = paths[i];
  92                 int matchlen = pathlens[i];
  93
  94                 if (baselen >= matchlen) {
  95                         /* If it doesn't match, move along... */
  96                         if (strncmp(base, match, matchlen))
  97                                 continue;
  98
  99                         /* The base is a subdirectory of a path which was specified. */
 100                         return 1;
 101                 }
 102
 103                 /* Does the base match? */
 104                 if (strncmp(base, match, baselen))
 105                         continue;
 106
 107                 match += baselen;
 108                 matchlen -= baselen;
 109
 110                 if (pathlen > matchlen)
 111                         continue;
 112
 113                 if (matchlen > pathlen) {
 114                         if (match[pathlen] != '/')
 115                                 continue;
 116                         if (!S_ISDIR(mode))
 117                                 continue;
 118                 }
 119
 120                 if (strncmp(path, match, pathlen))
 121                         continue;
 122
 123                 return 1;
 124         }
 125         return 0; /* No matches */
 126 }
 127
 128 /* A whole sub-tree went away or appeared */
 129 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
 130 {
 131         while (desc->size) {
 132                 if (interesting(desc, base))
 133                         show_entry(opt, prefix, desc, base);
 134                 update_tree_entry(desc);
 135         }
 136 }
 137
 138 /* A file entry went away or appeared */
 139 static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
 140 {
 141         unsigned mode;
 142         const char *path;
 143         const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
 144
 145         if (opt->recursive && S_ISDIR(mode)) {
 146                 char type[20];
 147                 char *newbase = malloc_base(base, path, strlen(path));
 148                 struct tree_desc inner;
 149                 void *tree;
 150
 151                 tree = read_sha1_file(sha1, type, &inner.size);
 152                 if (!tree || strcmp(type, tree_type))
 153                         die("corrupt tree sha %s", sha1_to_hex(sha1));
 154
 155                 inner.buf = tree;
 156                 show_tree(opt, prefix, &inner, newbase);
 157
 158                 free(tree);
 159                 free(newbase);
 160                 return 0;
 161         }
 162
 163         opt->add_remove(opt, prefix[0], mode, sha1, base, path);
 164         return 0;
 165 }
 166
 167 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 168 {
 169         while (t1->size | t2->size) {
 170                 if (nr_paths && t1->size && !interesting(t1, base)) {
 171                         update_tree_entry(t1);
 172                         continue;
 173                 }
 174                 if (nr_paths && t2->size && !interesting(t2, base)) {
 175                         update_tree_entry(t2);
 176                         continue;
 177                 }
 178                 if (!t1->size) {
 179                         show_entry(opt, "+", t2, base);
 180                         update_tree_entry(t2);
 181                         continue;
 182                 }
 183                 if (!t2->size) {
 184                         show_entry(opt, "-", t1, base);
 185                         update_tree_entry(t1);
 186                         continue;
 187                 }
 188                 switch (compare_tree_entry(t1, t2, base, opt)) {
 189                 case -1:
 190                         update_tree_entry(t1);
 191                         continue;
 192                 case 0:
 193                         update_tree_entry(t1);
 194                         /* Fallthrough */
 195                 case 1:
 196                         update_tree_entry(t2);
 197                         continue;
 198                 }
 199                 die("git-diff-tree: internal error");
 200         }
 201         return 0;
 202 }
 203
 204 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
 205 {
 206         void *tree1, *tree2;
 207         struct tree_desc t1, t2;
 208         int retval;
 209
 210         tree1 = read_object_with_reference(old, tree_type, &t1.size, NULL);
 211         if (!tree1)
 212                 die("unable to read source tree (%s)", sha1_to_hex(old));
 213         tree2 = read_object_with_reference(new, tree_type, &t2.size, NULL);
 214         if (!tree2)
 215                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 216         t1.buf = tree1;
 217         t2.buf = tree2;
 218         retval = diff_tree(&t1, &t2, base, opt);
 219         free(tree1);
 220         free(tree2);
 221         return retval;
 222 }
 223
 224 static int count_paths(const char **paths)
 225 {
 226         int i = 0;
 227         while (*paths++)
 228                 i++;
 229         return i;
 230 }
 231
 232 void diff_tree_setup_paths(const char **p)
 233 {
 234         if (p) {
 235                 int i;
 236
 237                 paths = p;
 238                 nr_paths = count_paths(paths);
 239                 if (nr_paths == 0) {
 240                         pathlens = NULL;
 241                         return;
 242                 }
 243                 pathlens = xmalloc(nr_paths * sizeof(int));
 244                 for (i=0; i<nr_paths; i++)
 245                         pathlens[i] = strlen(paths[i]);
 246         }
 247 }