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, int baselen, const char *path, int pathlen)
   9{
  10        char *newbase = xmalloc(baselen + pathlen + 2);
  11        memcpy(newbase, base, baselen);
  12        memcpy(newbase + baselen, path, pathlen);
  13        memcpy(newbase + baselen + pathlen, "/", 2);
  14        return newbase;
  15}
  16
  17static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
  18                       const char *base, int baselen);
  19
  20static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
  21{
  22        unsigned mode1, mode2;
  23        const char *path1, *path2;
  24        const unsigned char *sha1, *sha2;
  25        int cmp, pathlen1, pathlen2;
  26
  27        sha1 = tree_entry_extract(t1, &path1, &mode1);
  28        sha2 = tree_entry_extract(t2, &path2, &mode2);
  29
  30        pathlen1 = tree_entry_len(path1, sha1);
  31        pathlen2 = tree_entry_len(path2, sha2);
  32        cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
  33        if (cmp < 0) {
  34                show_entry(opt, "-", t1, base, baselen);
  35                return -1;
  36        }
  37        if (cmp > 0) {
  38                show_entry(opt, "+", t2, base, baselen);
  39                return 1;
  40        }
  41        if (!opt->find_copies_harder && !hashcmp(sha1, sha2) && mode1 == mode2)
  42                return 0;
  43
  44        /*
  45         * If the filemode has changed to/from a directory from/to a regular
  46         * file, we need to consider it a remove and an add.
  47         */
  48        if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
  49                show_entry(opt, "-", t1, base, baselen);
  50                show_entry(opt, "+", t2, base, baselen);
  51                return 0;
  52        }
  53
  54        if (opt->recursive && S_ISDIR(mode1)) {
  55                int retval;
  56                char *newbase = malloc_base(base, baselen, path1, pathlen1);
  57                if (opt->tree_in_recursive)
  58                        opt->change(opt, mode1, mode2,
  59                                    sha1, sha2, base, path1);
  60                retval = diff_tree_sha1(sha1, sha2, newbase, opt);
  61                free(newbase);
  62                return retval;
  63        }
  64
  65        opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
  66        return 0;
  67}
  68
  69static int interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
  70{
  71        const char *path;
  72        const unsigned char *sha1;
  73        unsigned mode;
  74        int i;
  75        int pathlen;
  76
  77        if (!opt->nr_paths)
  78                return 1;
  79
  80        sha1 = tree_entry_extract(desc, &path, &mode);
  81
  82        pathlen = tree_entry_len(path, sha1);
  83
  84        for (i=0; i < opt->nr_paths; i++) {
  85                const char *match = opt->paths[i];
  86                int matchlen = opt->pathlens[i];
  87
  88                if (baselen >= matchlen) {
  89                        /* If it doesn't match, move along... */
  90                        if (strncmp(base, match, matchlen))
  91                                continue;
  92
  93                        /* The base is a subdirectory of a path which was specified. */
  94                        return 1;
  95                }
  96
  97                /* Does the base match? */
  98                if (strncmp(base, match, baselen))
  99                        continue;
 100
 101                match += baselen;
 102                matchlen -= baselen;
 103
 104                if (pathlen > matchlen)
 105                        continue;
 106
 107                if (matchlen > pathlen) {
 108                        if (match[pathlen] != '/')
 109                                continue;
 110                        if (!S_ISDIR(mode))
 111                                continue;
 112                }
 113
 114                if (strncmp(path, match, pathlen))
 115                        continue;
 116
 117                return 1;
 118        }
 119        return 0; /* No matches */
 120}
 121
 122/* A whole sub-tree went away or appeared */
 123static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
 124{
 125        while (desc->size) {
 126                if (interesting(desc, base, baselen, opt))
 127                        show_entry(opt, prefix, desc, base, baselen);
 128                update_tree_entry(desc);
 129        }
 130}
 131
 132/* A file entry went away or appeared */
 133static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
 134                       const char *base, int baselen)
 135{
 136        unsigned mode;
 137        const char *path;
 138        const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
 139
 140        if (opt->recursive && S_ISDIR(mode)) {
 141                enum object_type type;
 142                int pathlen = tree_entry_len(path, sha1);
 143                char *newbase = malloc_base(base, baselen, path, pathlen);
 144                struct tree_desc inner;
 145                void *tree;
 146
 147                tree = read_sha1_file(sha1, &type, &inner.size);
 148                if (!tree || type != OBJ_TREE)
 149                        die("corrupt tree sha %s", sha1_to_hex(sha1));
 150
 151                inner.buf = tree;
 152                show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
 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        int baselen = strlen(base);
 164
 165        while (t1->size | t2->size) {
 166                if (opt->nr_paths && t1->size && !interesting(t1, base, baselen, opt)) {
 167                        update_tree_entry(t1);
 168                        continue;
 169                }
 170                if (opt->nr_paths && t2->size && !interesting(t2, base, baselen, opt)) {
 171                        update_tree_entry(t2);
 172                        continue;
 173                }
 174                if (!t1->size) {
 175                        show_entry(opt, "+", t2, base, baselen);
 176                        update_tree_entry(t2);
 177                        continue;
 178                }
 179                if (!t2->size) {
 180                        show_entry(opt, "-", t1, base, baselen);
 181                        update_tree_entry(t1);
 182                        continue;
 183                }
 184                switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
 185                case -1:
 186                        update_tree_entry(t1);
 187                        continue;
 188                case 0:
 189                        update_tree_entry(t1);
 190                        /* Fallthrough */
 191                case 1:
 192                        update_tree_entry(t2);
 193                        continue;
 194                }
 195                die("git-diff-tree: internal error");
 196        }
 197        return 0;
 198}
 199
 200int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
 201{
 202        void *tree1, *tree2;
 203        struct tree_desc t1, t2;
 204        int retval;
 205
 206        tree1 = read_object_with_reference(old, tree_type, &t1.size, NULL);
 207        if (!tree1)
 208                die("unable to read source tree (%s)", sha1_to_hex(old));
 209        tree2 = read_object_with_reference(new, tree_type, &t2.size, NULL);
 210        if (!tree2)
 211                die("unable to read destination tree (%s)", sha1_to_hex(new));
 212        t1.buf = tree1;
 213        t2.buf = tree2;
 214        retval = diff_tree(&t1, &t2, base, opt);
 215        free(tree1);
 216        free(tree2);
 217        return retval;
 218}
 219
 220int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
 221{
 222        int retval;
 223        void *tree;
 224        struct tree_desc empty, real;
 225
 226        tree = read_object_with_reference(new, tree_type, &real.size, NULL);
 227        if (!tree)
 228                die("unable to read root tree (%s)", sha1_to_hex(new));
 229        real.buf = tree;
 230
 231        empty.size = 0;
 232        empty.buf = "";
 233        retval = diff_tree(&empty, &real, base, opt);
 234        free(tree);
 235        return retval;
 236}
 237
 238static int count_paths(const char **paths)
 239{
 240        int i = 0;
 241        while (*paths++)
 242                i++;
 243        return i;
 244}
 245
 246void diff_tree_release_paths(struct diff_options *opt)
 247{
 248        free(opt->pathlens);
 249}
 250
 251void diff_tree_setup_paths(const char **p, struct diff_options *opt)
 252{
 253        opt->nr_paths = 0;
 254        opt->pathlens = NULL;
 255        opt->paths = NULL;
 256
 257        if (p) {
 258                int i;
 259
 260                opt->paths = p;
 261                opt->nr_paths = count_paths(p);
 262                if (opt->nr_paths == 0) {
 263                        opt->pathlens = NULL;
 264                        return;
 265                }
 266                opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
 267                for (i=0; i < opt->nr_paths; i++)
 268                        opt->pathlens[i] = strlen(p[i]);
 269        }
 270}