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