Andrew's git - gitweb.git/blob

   1/*
   2 * Helper functions for tree diff generation
   3 */
   4#include "cache.h"
   5#include "diff.h"
   6#include "tree.h"
   7
   8static 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
  18static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
  19                       const char *base);
  20
  21static 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
  70static 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 */
 124static 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 */
 134static 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
 161int 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
 198int 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
 218int 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
 236static int count_paths(const char **paths)
 237{
 238        int i = 0;
 239        while (*paths++)
 240                i++;
 241        return i;
 242}
 243
 244void diff_tree_release_paths(struct diff_options *opt)
 245{
 246        free(opt->pathlens);
 247}
 248
 249void 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}