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 && !hashcmp(sha1, sha2) && mode1 == mode2)
  43                 return 0;
  44
  45         /*
  46          * If the filemode has changed to/from a directory from/to a regular
  47          * file, we need to consider it a remove and an add.
  48          */
  49         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
  50                 show_entry(opt, "-", t1, base);
  51                 show_entry(opt, "+", t2, base);
  52                 return 0;
  53         }
  54
  55         if (opt->recursive && S_ISDIR(mode1)) {
  56                 int retval;
  57                 char *newbase = malloc_base(base, path1, pathlen1);
  58                 if (opt->tree_in_recursive)
  59                         opt->change(opt, mode1, mode2,
  60                                     sha1, sha2, base, path1);
  61                 retval = diff_tree_sha1(sha1, sha2, newbase, opt);
  62                 free(newbase);
  63                 return retval;
  64         }
  65
  66         opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
  67         return 0;
  68 }
  69
  70 static int interesting(struct tree_desc *desc, const char *base, struct diff_options *opt)
  71 {
  72         const char *path;
  73         unsigned mode;
  74         int i;
  75         int baselen, pathlen;
  76
  77         if (!opt->nr_paths)
  78                 return 1;
  79
  80         (void)tree_entry_extract(desc, &path, &mode);
  81
  82         pathlen = strlen(path);
  83         baselen = strlen(base);
  84
  85         for (i=0; i < opt->nr_paths; i++) {
  86                 const char *match = opt->paths[i];
  87                 int matchlen = opt->pathlens[i];
  88
  89                 if (baselen >= matchlen) {
  90                         /* If it doesn't match, move along... */
  91                         if (strncmp(base, match, matchlen))
  92                                 continue;
  93
  94                         /* The base is a subdirectory of a path which was specified. */
  95                         return 1;
  96                 }
  97
  98                 /* Does the base match? */
  99                 if (strncmp(base, match, baselen))
 100                         continue;
 101
 102                 match += baselen;
 103                 matchlen -= baselen;
 104
 105                 if (pathlen > matchlen)
 106                         continue;
 107
 108                 if (matchlen > pathlen) {
 109                         if (match[pathlen] != '/')
 110                                 continue;
 111                         if (!S_ISDIR(mode))
 112                                 continue;
 113                 }
 114
 115                 if (strncmp(path, match, pathlen))
 116                         continue;
 117
 118                 return 1;
 119         }
 120         return 0; /* No matches */
 121 }
 122
 123 /* A whole sub-tree went away or appeared */
 124 static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
 125 {
 126         while (desc->size) {
 127                 if (interesting(desc, base, opt))
 128                         show_entry(opt, prefix, desc, base);
 129                 update_tree_entry(desc);
 130         }
 131 }
 132
 133 /* A file entry went away or appeared */
 134 static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
 135                        const char *base)
 136 {
 137         unsigned mode;
 138         const char *path;
 139         const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
 140
 141         if (opt->recursive && S_ISDIR(mode)) {
 142                 char type[20];
 143                 char *newbase = malloc_base(base, path, strlen(path));
 144                 struct tree_desc inner;
 145                 void *tree;
 146
 147                 tree = read_sha1_file(sha1, type, &inner.size);
 148                 if (!tree || strcmp(type, tree_type))
 149                         die("corrupt tree sha %s", sha1_to_hex(sha1));
 150
 151                 inner.buf = tree;
 152                 show_tree(opt, prefix, &inner, newbase);
 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         while (t1->size | t2->size) {
 164                 if (opt->nr_paths && t1->size && !interesting(t1, base, opt)) {
 165                         update_tree_entry(t1);
 166                         continue;
 167                 }
 168                 if (opt->nr_paths && t2->size && !interesting(t2, base, opt)) {
 169                         update_tree_entry(t2);
 170                         continue;
 171                 }
 172                 if (!t1->size) {
 173                         show_entry(opt, "+", t2, base);
 174                         update_tree_entry(t2);
 175                         continue;
 176                 }
 177                 if (!t2->size) {
 178                         show_entry(opt, "-", t1, base);
 179                         update_tree_entry(t1);
 180                         continue;
 181                 }
 182                 switch (compare_tree_entry(t1, t2, base, opt)) {
 183                 case -1:
 184                         update_tree_entry(t1);
 185                         continue;
 186                 case 0:
 187                         update_tree_entry(t1);
 188                         /* Fallthrough */
 189                 case 1:
 190                         update_tree_entry(t2);
 191                         continue;
 192                 }
 193                 die("git-diff-tree: internal error");
 194         }
 195         return 0;
 196 }
 197
 198 int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
 199 {
 200         void *tree1, *tree2;
 201         struct tree_desc t1, t2;
 202         int retval;
 203
 204         tree1 = read_object_with_reference(old, tree_type, &t1.size, NULL);
 205         if (!tree1)
 206                 die("unable to read source tree (%s)", sha1_to_hex(old));
 207         tree2 = read_object_with_reference(new, tree_type, &t2.size, NULL);
 208         if (!tree2)
 209                 die("unable to read destination tree (%s)", sha1_to_hex(new));
 210         t1.buf = tree1;
 211         t2.buf = tree2;
 212         retval = diff_tree(&t1, &t2, base, opt);
 213         free(tree1);
 214         free(tree2);
 215         return retval;
 216 }
 217
 218 int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
 219 {
 220         int retval;
 221         void *tree;
 222         struct tree_desc empty, real;
 223
 224         tree = read_object_with_reference(new, tree_type, &real.size, NULL);
 225         if (!tree)
 226                 die("unable to read root tree (%s)", sha1_to_hex(new));
 227         real.buf = tree;
 228
 229         empty.size = 0;
 230         empty.buf = "";
 231         retval = diff_tree(&empty, &real, base, opt);
 232         free(tree);
 233         return retval;
 234 }
 235
 236 static int count_paths(const char **paths)
 237 {
 238         int i = 0;
 239         while (*paths++)
 240                 i++;
 241         return i;
 242 }
 243
 244 void diff_tree_release_paths(struct diff_options *opt)
 245 {
 246         free(opt->pathlens);
 247 }
 248
 249 void diff_tree_setup_paths(const char **p, struct diff_options *opt)
 250 {
 251         opt->nr_paths = 0;
 252         opt->pathlens = NULL;
 253         opt->paths = NULL;
 254
 255         if (p) {
 256                 int i;
 257
 258                 opt->paths = p;
 259                 opt->nr_paths = count_paths(p);
 260                 if (opt->nr_paths == 0) {
 261                         opt->pathlens = NULL;
 262                         return;
 263                 }
 264                 opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
 265                 for (i=0; i < opt->nr_paths; i++)
 266                         opt->pathlens[i] = strlen(p[i]);
 267         }
 268 }