Andrew's git - gitweb.git/blob

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