315eb5c26ac347a54ff0a4013ad40844ecf2812e
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include <sys/types.h>
   5#include <sys/wait.h>
   6#include <signal.h>
   7#include "cache.h"
   8#include "diff.h"
   9#include "diffcore.h"
  10
  11static const char *diff_opts = "-pu";
  12static unsigned char null_sha1[20] = { 0, };
  13
  14static int reverse_diff;
  15static int use_size_cache;
  16
  17static const char *external_diff(void)
  18{
  19        static const char *external_diff_cmd = NULL;
  20        static int done_preparing = 0;
  21
  22        if (done_preparing)
  23                return external_diff_cmd;
  24
  25        /*
  26         * Default values above are meant to match the
  27         * Linux kernel development style.  Examples of
  28         * alternative styles you can specify via environment
  29         * variables are:
  30         *
  31         * GIT_DIFF_OPTS="-c";
  32         */
  33        if (gitenv("GIT_EXTERNAL_DIFF"))
  34                external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
  35
  36        /* In case external diff fails... */
  37        diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
  38
  39        done_preparing = 1;
  40        return external_diff_cmd;
  41}
  42
  43/* Help to copy the thing properly quoted for the shell safety.
  44 * any single quote is replaced with '\'', and the caller is
  45 * expected to enclose the result within a single quote pair.
  46 *
  47 * E.g.
  48 *  original     sq_expand     result
  49 *  name     ==> name      ==> 'name'
  50 *  a b      ==> a b       ==> 'a b'
  51 *  a'b      ==> a'\''b    ==> 'a'\''b'
  52 */
  53static char *sq_expand(const char *src)
  54{
  55        static char *buf = NULL;
  56        int cnt, c;
  57        const char *cp;
  58        char *bp;
  59
  60        /* count bytes needed to store the quoted string. */
  61        for (cnt = 1, cp = src; *cp; cnt++, cp++)
  62                if (*cp == '\'')
  63                        cnt += 3;
  64
  65        buf = xmalloc(cnt);
  66        bp = buf;
  67        while ((c = *src++)) {
  68                if (c != '\'')
  69                        *bp++ = c;
  70                else {
  71                        bp = strcpy(bp, "'\\''");
  72                        bp += 4;
  73                }
  74        }
  75        *bp = 0;
  76        return buf;
  77}
  78
  79static struct diff_tempfile {
  80        const char *name; /* filename external diff should read from */
  81        char hex[41];
  82        char mode[10];
  83        char tmp_path[50];
  84} diff_temp[2];
  85
  86static void builtin_diff(const char *name_a,
  87                         const char *name_b,
  88                         struct diff_tempfile *temp,
  89                         const char *xfrm_msg)
  90{
  91        int i, next_at, cmd_size;
  92        const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
  93        const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
  94        const char *input_name_sq[2];
  95        const char *path0[2];
  96        const char *path1[2];
  97        const char *name_sq[2];
  98        char *cmd;
  99
 100        name_sq[0] = sq_expand(name_a);
 101        name_sq[1] = sq_expand(name_b);
 102
 103        /* diff_cmd and diff_arg have 6 %s in total which makes
 104         * the sum of these strings 12 bytes larger than required.
 105         * we use 2 spaces around diff-opts, and we need to count
 106         * terminating NUL, so we subtract 9 here.
 107         */
 108        cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
 109                        strlen(diff_arg) - 9);
 110        for (i = 0; i < 2; i++) {
 111                input_name_sq[i] = sq_expand(temp[i].name);
 112                if (!strcmp(temp[i].name, "/dev/null")) {
 113                        path0[i] = "/dev/null";
 114                        path1[i] = "";
 115                } else {
 116                        path0[i] = i ? "b/" : "a/";
 117                        path1[i] = name_sq[i];
 118                }
 119                cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
 120                             strlen(input_name_sq[i]));
 121        }
 122
 123        cmd = xmalloc(cmd_size);
 124
 125        next_at = 0;
 126        next_at += snprintf(cmd+next_at, cmd_size-next_at,
 127                            diff_cmd,
 128                            path0[0], path1[0], path0[1], path1[1]);
 129        next_at += snprintf(cmd+next_at, cmd_size-next_at,
 130                            " %s ", diff_opts);
 131        next_at += snprintf(cmd+next_at, cmd_size-next_at,
 132                            diff_arg, input_name_sq[0], input_name_sq[1]);
 133
 134        printf("diff --git a/%s b/%s\n", name_a, name_b);
 135        if (!path1[0][0]) {
 136                printf("new file mode %s\n", temp[1].mode);
 137                if (xfrm_msg && xfrm_msg[0])
 138                        puts(xfrm_msg);
 139        }
 140        else if (!path1[1][0]) {
 141                printf("deleted file mode %s\n", temp[0].mode);
 142                if (xfrm_msg && xfrm_msg[0])
 143                        puts(xfrm_msg);
 144        }
 145        else {
 146                if (strcmp(temp[0].mode, temp[1].mode)) {
 147                        printf("old mode %s\n", temp[0].mode);
 148                        printf("new mode %s\n", temp[1].mode);
 149                }
 150                if (xfrm_msg && xfrm_msg[0])
 151                        puts(xfrm_msg);
 152
 153                if (strncmp(temp[0].mode, temp[1].mode, 3))
 154                        /* we do not run diff between different kind
 155                         * of objects.
 156                         */
 157                        exit(0);
 158        }
 159        fflush(NULL);
 160        execlp("/bin/sh","sh", "-c", cmd, NULL);
 161}
 162
 163struct diff_filespec *alloc_filespec(const char *path)
 164{
 165        int namelen = strlen(path);
 166        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 167        spec->path = (char *)(spec + 1);
 168        strcpy(spec->path, path);
 169        spec->should_free = spec->should_munmap = 0;
 170        spec->xfrm_flags = 0;
 171        spec->size = 0;
 172        spec->data = NULL;
 173        spec->mode = 0;
 174        memset(spec->sha1, 0, 20);
 175        return spec;
 176}
 177
 178void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 179                   unsigned short mode)
 180{
 181        if (mode) {
 182                spec->mode = DIFF_FILE_CANON_MODE(mode);
 183                memcpy(spec->sha1, sha1, 20);
 184                spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 185        }
 186}
 187
 188/*
 189 * Given a name and sha1 pair, if the dircache tells us the file in
 190 * the work tree has that object contents, return true, so that
 191 * prepare_temp_file() does not have to inflate and extract.
 192 */
 193static int work_tree_matches(const char *name, const unsigned char *sha1)
 194{
 195        struct cache_entry *ce;
 196        struct stat st;
 197        int pos, len;
 198
 199        /* We do not read the cache ourselves here, because the
 200         * benchmark with my previous version that always reads cache
 201         * shows that it makes things worse for diff-tree comparing
 202         * two linux-2.6 kernel trees in an already checked out work
 203         * tree.  This is because most diff-tree comparisons deal with
 204         * only a small number of files, while reading the cache is
 205         * expensive for a large project, and its cost outweighs the
 206         * savings we get by not inflating the object to a temporary
 207         * file.  Practically, this code only helps when we are used
 208         * by diff-cache --cached, which does read the cache before
 209         * calling us.
 210         */
 211        if (!active_cache)
 212                return 0;
 213
 214        len = strlen(name);
 215        pos = cache_name_pos(name, len);
 216        if (pos < 0)
 217                return 0;
 218        ce = active_cache[pos];
 219        if ((lstat(name, &st) < 0) ||
 220            !S_ISREG(st.st_mode) || /* careful! */
 221            ce_match_stat(ce, &st) ||
 222            memcmp(sha1, ce->sha1, 20))
 223                return 0;
 224        /* we return 1 only when we can stat, it is a regular file,
 225         * stat information matches, and sha1 recorded in the cache
 226         * matches.  I.e. we know the file in the work tree really is
 227         * the same as the <name, sha1> pair.
 228         */
 229        return 1;
 230}
 231
 232static struct sha1_size_cache {
 233        unsigned char sha1[20];
 234        unsigned long size;
 235} **sha1_size_cache;
 236static int sha1_size_cache_nr, sha1_size_cache_alloc;
 237
 238static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
 239                                                 unsigned long size)
 240{
 241        int first, last;
 242        struct sha1_size_cache *e;
 243
 244        first = 0;
 245        last = sha1_size_cache_nr;
 246        while (last > first) {
 247                int next = (last + first) >> 1;
 248                e = sha1_size_cache[next];
 249                int cmp = memcmp(e->sha1, sha1, 20);
 250                if (!cmp)
 251                        return e;
 252                if (cmp < 0) {
 253                        last = next;
 254                        continue;
 255                }
 256                first = next+1;
 257        }
 258        /* not found */
 259        if (size == UINT_MAX)
 260                return NULL;
 261        /* insert to make it at "first" */
 262        if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
 263                sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
 264                sha1_size_cache = xrealloc(sha1_size_cache,
 265                                           sha1_size_cache_alloc *
 266                                           sizeof(*sha1_size_cache));
 267        }
 268        sha1_size_cache_nr++;
 269        if (first < sha1_size_cache_nr)
 270                memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
 271                        (sha1_size_cache_nr - first - 1) *
 272                        sizeof(*sha1_size_cache));
 273        e = xmalloc(sizeof(struct sha1_size_cache));
 274        sha1_size_cache[first] = e;
 275        memcpy(e->sha1, sha1, 20);
 276        e->size = size;
 277        return e;
 278}
 279
 280/*
 281 * While doing rename detection and pickaxe operation, we may need to
 282 * grab the data for the blob (or file) for our own in-core comparison.
 283 * diff_filespec has data and size fields for this purpose.
 284 */
 285int diff_populate_filespec(struct diff_filespec *s, int size_only)
 286{
 287        int err = 0;
 288        if (!DIFF_FILE_VALID(s))
 289                die("internal error: asking to populate invalid file.");
 290        if (S_ISDIR(s->mode))
 291                return -1;
 292
 293        if (!use_size_cache)
 294                size_only = 0;
 295
 296        if (s->data)
 297                return err;
 298        if (!s->sha1_valid ||
 299            work_tree_matches(s->path, s->sha1)) {
 300                struct stat st;
 301                int fd;
 302                if (lstat(s->path, &st) < 0) {
 303                        if (errno == ENOENT) {
 304                        err_empty:
 305                                err = -1;
 306                        empty:
 307                                s->data = "";
 308                                s->size = 0;
 309                                return err;
 310                        }
 311                }
 312                s->size = st.st_size;
 313                if (!s->size)
 314                        goto empty;
 315                if (size_only)
 316                        return 0;
 317                if (S_ISLNK(st.st_mode)) {
 318                        int ret;
 319                        s->data = xmalloc(s->size);
 320                        s->should_free = 1;
 321                        ret = readlink(s->path, s->data, s->size);
 322                        if (ret < 0) {
 323                                free(s->data);
 324                                goto err_empty;
 325                        }
 326                        return 0;
 327                }
 328                fd = open(s->path, O_RDONLY);
 329                if (fd < 0)
 330                        goto err_empty;
 331                s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
 332                s->should_munmap = 1;
 333                close(fd);
 334        }
 335        else {
 336                char type[20];
 337                struct sha1_size_cache *e;
 338
 339                if (size_only) {
 340                        e = locate_size_cache(s->sha1, UINT_MAX);
 341                        if (e) {
 342                                s->size = e->size;
 343                                return 0;
 344                        }
 345                        if (!sha1_file_size(s->sha1, &s->size))
 346                                locate_size_cache(s->sha1, s->size);
 347                }
 348                else {
 349                        s->data = read_sha1_file(s->sha1, type, &s->size);
 350                        s->should_free = 1;
 351                }
 352        }
 353        return 0;
 354}
 355
 356void diff_free_filespec_data(struct diff_filespec *s)
 357{
 358        if (s->should_free)
 359                free(s->data);
 360        else if (s->should_munmap)
 361                munmap(s->data, s->size);
 362        s->should_free = s->should_munmap = 0;
 363        s->data = NULL;
 364}
 365
 366static void prep_temp_blob(struct diff_tempfile *temp,
 367                           void *blob,
 368                           unsigned long size,
 369                           unsigned char *sha1,
 370                           int mode)
 371{
 372        int fd;
 373
 374        strcpy(temp->tmp_path, ".diff_XXXXXX");
 375        fd = mkstemp(temp->tmp_path);
 376        if (fd < 0)
 377                die("unable to create temp-file");
 378        if (write(fd, blob, size) != size)
 379                die("unable to write temp-file");
 380        close(fd);
 381        temp->name = temp->tmp_path;
 382        strcpy(temp->hex, sha1_to_hex(sha1));
 383        temp->hex[40] = 0;
 384        sprintf(temp->mode, "%06o", mode);
 385}
 386
 387static void prepare_temp_file(const char *name,
 388                              struct diff_tempfile *temp,
 389                              struct diff_filespec *one)
 390{
 391        if (!DIFF_FILE_VALID(one)) {
 392        not_a_valid_file:
 393                /* A '-' entry produces this for file-2, and
 394                 * a '+' entry produces this for file-1.
 395                 */
 396                temp->name = "/dev/null";
 397                strcpy(temp->hex, ".");
 398                strcpy(temp->mode, ".");
 399                return;
 400        }
 401
 402        if (!one->sha1_valid ||
 403            work_tree_matches(name, one->sha1)) {
 404                struct stat st;
 405                if (lstat(name, &st) < 0) {
 406                        if (errno == ENOENT)
 407                                goto not_a_valid_file;
 408                        die("stat(%s): %s", name, strerror(errno));
 409                }
 410                if (S_ISLNK(st.st_mode)) {
 411                        int ret;
 412                        char *buf, buf_[1024];
 413                        buf = ((sizeof(buf_) < st.st_size) ?
 414                               xmalloc(st.st_size) : buf_);
 415                        ret = readlink(name, buf, st.st_size);
 416                        if (ret < 0)
 417                                die("readlink(%s)", name);
 418                        prep_temp_blob(temp, buf, st.st_size,
 419                                       (one->sha1_valid ?
 420                                        one->sha1 : null_sha1),
 421                                       (one->sha1_valid ?
 422                                        one->mode : S_IFLNK));
 423                }
 424                else {
 425                        /* we can borrow from the file in the work tree */
 426                        temp->name = name;
 427                        if (!one->sha1_valid)
 428                                strcpy(temp->hex, sha1_to_hex(null_sha1));
 429                        else
 430                                strcpy(temp->hex, sha1_to_hex(one->sha1));
 431                        /* Even though we may sometimes borrow the
 432                         * contents from the work tree, we always want
 433                         * one->mode.  mode is trustworthy even when
 434                         * !(one->sha1_valid), as long as
 435                         * DIFF_FILE_VALID(one).
 436                         */
 437                        sprintf(temp->mode, "%06o", one->mode);
 438                }
 439                return;
 440        }
 441        else {
 442                if (diff_populate_filespec(one, 0))
 443                        die("cannot read data blob for %s", one->path);
 444                prep_temp_blob(temp, one->data, one->size,
 445                               one->sha1, one->mode);
 446        }
 447}
 448
 449static void remove_tempfile(void)
 450{
 451        int i;
 452
 453        for (i = 0; i < 2; i++)
 454                if (diff_temp[i].name == diff_temp[i].tmp_path) {
 455                        unlink(diff_temp[i].name);
 456                        diff_temp[i].name = NULL;
 457                }
 458}
 459
 460static void remove_tempfile_on_signal(int signo)
 461{
 462        remove_tempfile();
 463}
 464
 465/* An external diff command takes:
 466 *
 467 * diff-cmd name infile1 infile1-sha1 infile1-mode \
 468 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 469 *
 470 */
 471static void run_external_diff(const char *pgm,
 472                              const char *name,
 473                              const char *other,
 474                              struct diff_filespec *one,
 475                              struct diff_filespec *two,
 476                              const char *xfrm_msg)
 477{
 478        struct diff_tempfile *temp = diff_temp;
 479        pid_t pid;
 480        int status;
 481        static int atexit_asked = 0;
 482
 483        if (one && two) {
 484                prepare_temp_file(name, &temp[0], one);
 485                prepare_temp_file(other ? : name, &temp[1], two);
 486                if (! atexit_asked &&
 487                    (temp[0].name == temp[0].tmp_path ||
 488                     temp[1].name == temp[1].tmp_path)) {
 489                        atexit_asked = 1;
 490                        atexit(remove_tempfile);
 491                }
 492                signal(SIGINT, remove_tempfile_on_signal);
 493        }
 494
 495        fflush(NULL);
 496        pid = fork();
 497        if (pid < 0)
 498                die("unable to fork");
 499        if (!pid) {
 500                if (pgm) {
 501                        if (one && two) {
 502                                const char *exec_arg[10];
 503                                const char **arg = &exec_arg[0];
 504                                *arg++ = pgm;
 505                                *arg++ = name;
 506                                *arg++ = temp[0].name;
 507                                *arg++ = temp[0].hex;
 508                                *arg++ = temp[0].mode;
 509                                *arg++ = temp[1].name;
 510                                *arg++ = temp[1].hex;
 511                                *arg++ = temp[1].mode;
 512                                if (other) {
 513                                        *arg++ = other;
 514                                        *arg++ = xfrm_msg;
 515                                }
 516                                *arg = NULL;
 517                                execvp(pgm, (char *const*) exec_arg);
 518                        }
 519                        else
 520                                execlp(pgm, pgm, name, NULL);
 521                }
 522                /*
 523                 * otherwise we use the built-in one.
 524                 */
 525                if (one && two)
 526                        builtin_diff(name, other ? : name, temp, xfrm_msg);
 527                else
 528                        printf("* Unmerged path %s\n", name);
 529                exit(0);
 530        }
 531        if (waitpid(pid, &status, 0) < 0 ||
 532            !WIFEXITED(status) || WEXITSTATUS(status)) {
 533                /* Earlier we did not check the exit status because
 534                 * diff exits non-zero if files are different, and
 535                 * we are not interested in knowing that.  It was a
 536                 * mistake which made it harder to quit a diff-*
 537                 * session that uses the git-apply-patch-script as
 538                 * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 539                 * should also exit non-zero only when it wants to
 540                 * abort the entire diff-* session.
 541                 */
 542                remove_tempfile();
 543                fprintf(stderr, "external diff died, stopping at %s.\n", name);
 544                exit(1);
 545        }
 546        remove_tempfile();
 547}
 548
 549static void run_diff(const char *name,
 550                     const char *other,
 551                     struct diff_filespec *one,
 552                     struct diff_filespec *two,
 553                     const char *xfrm_msg)
 554{
 555        const char *pgm = external_diff();
 556        if (!pgm &&
 557            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
 558            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
 559                /* a filepair that changes between file and symlink
 560                 * needs to be split into deletion and creation.
 561                 */
 562                struct diff_filespec *null = alloc_filespec(two->path);
 563                run_external_diff(NULL, name, other, one, null, xfrm_msg);
 564                free(null);
 565                null = alloc_filespec(one->path);
 566                run_external_diff(NULL, name, other, null, two, xfrm_msg);
 567                free(null);
 568        }
 569        else
 570                run_external_diff(pgm, name, other, one, two, xfrm_msg);
 571}
 572
 573void diff_setup(int flags)
 574{
 575        if (flags & DIFF_SETUP_REVERSE)
 576                reverse_diff = 1;
 577        if (flags & DIFF_SETUP_USE_CACHE) {
 578                if (!active_cache)
 579                        /* read-cache does not die even when it fails
 580                         * so it is safe for us to do this here.  Also
 581                         * it does not smudge active_cache or active_nr
 582                         * when it fails, so we do not have to worry about
 583                         * cleaning it up oufselves either.
 584                         */
 585                        read_cache();
 586        }
 587        if (flags & DIFF_SETUP_USE_SIZE_CACHE)
 588                use_size_cache = 1;
 589        
 590}
 591
 592static int parse_num(const char **cp_p)
 593{
 594        int num, scale, ch, cnt;
 595        const char *cp = *cp_p;
 596
 597        cnt = num = 0;
 598        scale = 1;
 599        while ('0' <= (ch = *cp) && ch <= '9') {
 600                if (cnt++ < 5) {
 601                        /* We simply ignore more than 5 digits precision. */
 602                        scale *= 10;
 603                        num = num * 10 + ch - '0';
 604                }
 605                *cp++;
 606        }
 607        *cp_p = cp;
 608
 609        /* user says num divided by scale and we say internally that
 610         * is MAX_SCORE * num / scale.
 611         */
 612        return (MAX_SCORE * num / scale);
 613}
 614
 615int diff_scoreopt_parse(const char *opt)
 616{
 617        int opt1, opt2, cmd;
 618
 619        if (*opt++ != '-')
 620                return -1;
 621        cmd = *opt++;
 622        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
 623                return -1; /* that is not a -M, -C nor -B option */
 624
 625        opt1 = parse_num(&opt);
 626        if (cmd != 'B')
 627                opt2 = 0;
 628        else {
 629                if (*opt == 0)
 630                        opt2 = 0;
 631                else if (*opt != '/')
 632                        return -1; /* we expect -B80/99 or -B80 */
 633                else {
 634                        opt++;
 635                        opt2 = parse_num(&opt);
 636                }
 637        }
 638        if (*opt != 0)
 639                return -1;
 640        return opt1 | (opt2 << 16);
 641}
 642
 643struct diff_queue_struct diff_queued_diff;
 644
 645void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
 646{
 647        if (queue->alloc <= queue->nr) {
 648                queue->alloc = alloc_nr(queue->alloc);
 649                queue->queue = xrealloc(queue->queue,
 650                                        sizeof(dp) * queue->alloc);
 651        }
 652        queue->queue[queue->nr++] = dp;
 653}
 654
 655struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
 656                                 struct diff_filespec *one,
 657                                 struct diff_filespec *two)
 658{
 659        struct diff_filepair *dp = xmalloc(sizeof(*dp));
 660        dp->one = one;
 661        dp->two = two;
 662        dp->score = 0;
 663        dp->source_stays = 0;
 664        dp->broken_pair = 0;
 665        diff_q(queue, dp);
 666        return dp;
 667}
 668
 669void diff_free_filepair(struct diff_filepair *p)
 670{
 671        diff_free_filespec_data(p->one);
 672        diff_free_filespec_data(p->two);
 673        free(p);
 674}
 675
 676static void diff_flush_raw(struct diff_filepair *p,
 677                           int line_termination,
 678                           int inter_name_termination)
 679{
 680        int two_paths;
 681        char status[10];
 682
 683        if (line_termination) {
 684                const char *err = "path %s cannot be expressed without -z";
 685                if (strchr(p->one->path, line_termination) ||
 686                    strchr(p->one->path, inter_name_termination))
 687                        die(err, p->one->path);
 688                if (strchr(p->two->path, line_termination) ||
 689                    strchr(p->two->path, inter_name_termination))
 690                        die(err, p->two->path);
 691        }
 692
 693        switch (p->status) {
 694        case 'C': case 'R':
 695                two_paths = 1;
 696                sprintf(status, "%c%03d", p->status,
 697                        (int)(0.5 + p->score * 100.0/MAX_SCORE));
 698                break;
 699        case 'N': case 'D':
 700                two_paths = 0;
 701                if (p->score)
 702                        sprintf(status, "%c%03d", p->status,
 703                                (int)(0.5 + p->score * 100.0/MAX_SCORE));
 704                else {
 705                        status[0] = p->status;
 706                        status[1] = 0;
 707                }
 708                break;
 709        default:
 710                two_paths = 0;
 711                status[0] = p->status;
 712                status[1] = 0;
 713                break;
 714        }
 715        printf(":%06o %06o %s ",
 716               p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
 717        printf("%s %s%c%s",
 718               sha1_to_hex(p->two->sha1),
 719               status,
 720               inter_name_termination,
 721               p->one->path);
 722        if (two_paths)
 723                printf("%c%s", inter_name_termination, p->two->path);
 724        putchar(line_termination);
 725}
 726
 727int diff_unmodified_pair(struct diff_filepair *p)
 728{
 729        /* This function is written stricter than necessary to support
 730         * the currently implemented transformers, but the idea is to
 731         * let transformers to produce diff_filepairs any way they want,
 732         * and filter and clean them up here before producing the output.
 733         */
 734        struct diff_filespec *one, *two;
 735
 736        if (DIFF_PAIR_UNMERGED(p))
 737                return 0; /* unmerged is interesting */
 738
 739        one = p->one;
 740        two = p->two;
 741
 742        /* deletion, addition, mode or type change
 743         * and rename are all interesting.
 744         */
 745        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
 746            DIFF_PAIR_MODE_CHANGED(p) ||
 747            strcmp(one->path, two->path))
 748                return 0;
 749
 750        /* both are valid and point at the same path.  that is, we are
 751         * dealing with a change.
 752         */
 753        if (one->sha1_valid && two->sha1_valid &&
 754            !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
 755                return 1; /* no change */
 756        if (!one->sha1_valid && !two->sha1_valid)
 757                return 1; /* both look at the same file on the filesystem. */
 758        return 0;
 759}
 760
 761static void diff_flush_patch(struct diff_filepair *p)
 762{
 763        const char *name, *other;
 764        char msg_[PATH_MAX*2+200], *msg;
 765
 766        if (diff_unmodified_pair(p))
 767                return;
 768
 769        name = p->one->path;
 770        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
 771        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
 772            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
 773                return; /* no tree diffs in patch format */ 
 774
 775        switch (p->status) {
 776        case 'C':
 777                sprintf(msg_,
 778                        "similarity index %d%%\n"
 779                        "copy from %s\n"
 780                        "copy to %s",
 781                        (int)(0.5 + p->score * 100.0/MAX_SCORE),
 782                        p->one->path, p->two->path);
 783                msg = msg_;
 784                break;
 785        case 'R':
 786                sprintf(msg_,
 787                        "similarity index %d%%\n"
 788                        "rename old %s\n"
 789                        "rename new %s",
 790                        (int)(0.5 + p->score * 100.0/MAX_SCORE),
 791                        p->one->path, p->two->path);
 792                msg = msg_;
 793                break;
 794        case 'D': case 'N':
 795                if (DIFF_PAIR_BROKEN(p)) {
 796                        sprintf(msg_,
 797                                "dissimilarity index %d%%",
 798                                (int)(0.5 + p->score * 100.0/MAX_SCORE));
 799                        msg = msg_;
 800                }
 801                else
 802                        msg = NULL;
 803                break;
 804        default:
 805                msg = NULL;
 806        }
 807
 808        if (DIFF_PAIR_UNMERGED(p))
 809                run_diff(name, NULL, NULL, NULL, NULL);
 810        else
 811                run_diff(name, other, p->one, p->two, msg);
 812}
 813
 814int diff_queue_is_empty(void)
 815{
 816        struct diff_queue_struct *q = &diff_queued_diff;
 817        int i;
 818        for (i = 0; i < q->nr; i++)
 819                if (!diff_unmodified_pair(q->queue[i]))
 820                        return 0;
 821        return 1;
 822}
 823
 824#if DIFF_DEBUG
 825void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
 826{
 827        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
 828                x, one ? : "",
 829                s->path,
 830                DIFF_FILE_VALID(s) ? "valid" : "invalid",
 831                s->mode,
 832                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
 833        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
 834                x, one ? : "",
 835                s->size, s->xfrm_flags);
 836}
 837
 838void diff_debug_filepair(const struct diff_filepair *p, int i)
 839{
 840        diff_debug_filespec(p->one, i, "one");
 841        diff_debug_filespec(p->two, i, "two");
 842        fprintf(stderr, "score %d, status %c stays %d broken %d\n",
 843                p->score, p->status ? : '?',
 844                p->source_stays, p->broken_pair);
 845}
 846
 847void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
 848{
 849        int i;
 850        if (msg)
 851                fprintf(stderr, "%s\n", msg);
 852        fprintf(stderr, "q->nr = %d\n", q->nr);
 853        for (i = 0; i < q->nr; i++) {
 854                struct diff_filepair *p = q->queue[i];
 855                diff_debug_filepair(p, i);
 856        }
 857}
 858#endif
 859
 860static void diff_resolve_rename_copy(void)
 861{
 862        int i, j;
 863        struct diff_filepair *p, *pp;
 864        struct diff_queue_struct *q = &diff_queued_diff;
 865
 866        diff_debug_queue("resolve-rename-copy", q);
 867
 868        for (i = 0; i < q->nr; i++) {
 869                p = q->queue[i];
 870                p->status = 0; /* undecided */
 871                if (DIFF_PAIR_UNMERGED(p))
 872                        p->status = 'U';
 873                else if (!DIFF_FILE_VALID(p->one))
 874                        p->status = 'N';
 875                else if (!DIFF_FILE_VALID(p->two))
 876                        p->status = 'D';
 877                else if (DIFF_PAIR_TYPE_CHANGED(p))
 878                        p->status = 'T';
 879
 880                /* from this point on, we are dealing with a pair
 881                 * whose both sides are valid and of the same type, i.e.
 882                 * either in-place edit or rename/copy edit.
 883                 */
 884                else if (DIFF_PAIR_RENAME(p)) {
 885                        if (p->source_stays) {
 886                                p->status = 'C';
 887                                continue;
 888                        }
 889                        /* See if there is some other filepair that
 890                         * copies from the same source as us.  If so
 891                         * we are a copy.  Otherwise we are a rename.
 892                         */
 893                        for (j = i + 1; j < q->nr; j++) {
 894                                pp = q->queue[j];
 895                                if (strcmp(pp->one->path, p->one->path))
 896                                        continue; /* not us */
 897                                if (!DIFF_PAIR_RENAME(pp))
 898                                        continue; /* not a rename/copy */
 899                                /* pp is a rename/copy from the same source */
 900                                p->status = 'C';
 901                                break;
 902                        }
 903                        if (!p->status)
 904                                p->status = 'R';
 905                }
 906                else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
 907                         p->one->mode != p->two->mode)
 908                        p->status = 'M';
 909                else {
 910                        /* This is a "no-change" entry and should not
 911                         * happen anymore, but prepare for broken callers.
 912                         */
 913                        error("feeding unmodified %s to diffcore",
 914                              p->one->path);
 915                        p->status = 'X';
 916                }
 917        }
 918        diff_debug_queue("resolve-rename-copy done", q);
 919}
 920
 921void diff_flush(int diff_output_style, int resolve_rename_copy)
 922{
 923        struct diff_queue_struct *q = &diff_queued_diff;
 924        int i;
 925        int line_termination = '\n';
 926        int inter_name_termination = '\t';
 927
 928        if (diff_output_style == DIFF_FORMAT_MACHINE)
 929                line_termination = inter_name_termination = 0;
 930        if (resolve_rename_copy)
 931                diff_resolve_rename_copy();
 932
 933        for (i = 0; i < q->nr; i++) {
 934                struct diff_filepair *p = q->queue[i];
 935                if ((diff_output_style == DIFF_FORMAT_NO_OUTPUT) ||
 936                    (p->status == 'X'))
 937                        continue;
 938                if (p->status == 0)
 939                        die("internal error in diff-resolve-rename-copy");
 940                switch (diff_output_style) {
 941                case DIFF_FORMAT_PATCH:
 942                        diff_flush_patch(p);
 943                        break;
 944                case DIFF_FORMAT_HUMAN:
 945                case DIFF_FORMAT_MACHINE:
 946                        diff_flush_raw(p, line_termination,
 947                                       inter_name_termination);
 948                        break;
 949                }
 950        }
 951        for (i = 0; i < q->nr; i++)
 952                diff_free_filepair(q->queue[i]);
 953        free(q->queue);
 954        q->queue = NULL;
 955        q->nr = q->alloc = 0;
 956}
 957
 958void diffcore_std(const char **paths,
 959                  int detect_rename, int rename_score,
 960                  const char *pickaxe, int pickaxe_opts,
 961                  int break_opt,
 962                  const char *orderfile)
 963{
 964        if (paths && paths[0])
 965                diffcore_pathspec(paths);
 966        if (0 <= break_opt)
 967                diffcore_break(break_opt);
 968        if (detect_rename)
 969                diffcore_rename(detect_rename, rename_score);
 970        if (0 <= break_opt)
 971                diffcore_merge_broken();
 972        if (pickaxe)
 973                diffcore_pickaxe(pickaxe, pickaxe_opts);
 974        if (orderfile)
 975                diffcore_order(orderfile);
 976}
 977
 978void diff_addremove(int addremove, unsigned mode,
 979                    const unsigned char *sha1,
 980                    const char *base, const char *path)
 981{
 982        char concatpath[PATH_MAX];
 983        struct diff_filespec *one, *two;
 984
 985        /* This may look odd, but it is a preparation for
 986         * feeding "there are unchanged files which should
 987         * not produce diffs, but when you are doing copy
 988         * detection you would need them, so here they are"
 989         * entries to the diff-core.  They will be prefixed
 990         * with something like '=' or '*' (I haven't decided
 991         * which but should not make any difference).
 992         * Feeding the same new and old to diff_change() 
 993         * also has the same effect.
 994         * Before the final output happens, they are pruned after
 995         * merged into rename/copy pairs as appropriate.
 996         */
 997        if (reverse_diff)
 998                addremove = (addremove == '+' ? '-' :
 999                             addremove == '-' ? '+' : addremove);
1000
1001        if (!path) path = "";
1002        sprintf(concatpath, "%s%s", base, path);
1003        one = alloc_filespec(concatpath);
1004        two = alloc_filespec(concatpath);
1005
1006        if (addremove != '+')
1007                fill_filespec(one, sha1, mode);
1008        if (addremove != '-')
1009                fill_filespec(two, sha1, mode);
1010
1011        diff_queue(&diff_queued_diff, one, two);
1012}
1013
1014void diff_helper_input(unsigned old_mode,
1015                       unsigned new_mode,
1016                       const unsigned char *old_sha1,
1017                       const unsigned char *new_sha1,
1018                       const char *old_path,
1019                       int status,
1020                       int score,
1021                       const char *new_path)
1022{
1023        struct diff_filespec *one, *two;
1024        struct diff_filepair *dp;
1025
1026        one = alloc_filespec(old_path);
1027        two = alloc_filespec(new_path);
1028        if (old_mode)
1029                fill_filespec(one, old_sha1, old_mode);
1030        if (new_mode)
1031                fill_filespec(two, new_sha1, new_mode);
1032        dp = diff_queue(&diff_queued_diff, one, two);
1033        dp->score = score * MAX_SCORE / 100;
1034        dp->status = status;
1035}
1036
1037void diff_change(unsigned old_mode, unsigned new_mode,
1038                 const unsigned char *old_sha1,
1039                 const unsigned char *new_sha1,
1040                 const char *base, const char *path) 
1041{
1042        char concatpath[PATH_MAX];
1043        struct diff_filespec *one, *two;
1044
1045        if (reverse_diff) {
1046                unsigned tmp;
1047                const unsigned char *tmp_c;
1048                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1049                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1050        }
1051        if (!path) path = "";
1052        sprintf(concatpath, "%s%s", base, path);
1053        one = alloc_filespec(concatpath);
1054        two = alloc_filespec(concatpath);
1055        fill_filespec(one, old_sha1, old_mode);
1056        fill_filespec(two, new_sha1, new_mode);
1057
1058        diff_queue(&diff_queued_diff, one, two);
1059}
1060
1061void diff_unmerge(const char *path)
1062{
1063        struct diff_filespec *one, *two;
1064        one = alloc_filespec(path);
1065        two = alloc_filespec(path);
1066        diff_queue(&diff_queued_diff, one, two);
1067}