b14d897f196ddab42d56285ffe14f7f616b01f71
   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 "quote.h"
   9#include "diff.h"
  10#include "diffcore.h"
  11#include "delta.h"
  12#include "xdiff-interface.h"
  13
  14static int use_size_cache;
  15
  16int diff_rename_limit_default = -1;
  17
  18int git_diff_config(const char *var, const char *value)
  19{
  20        if (!strcmp(var, "diff.renamelimit")) {
  21                diff_rename_limit_default = git_config_int(var, value);
  22                return 0;
  23        }
  24
  25        return git_default_config(var, value);
  26}
  27
  28static char *quote_one(const char *str)
  29{
  30        int needlen;
  31        char *xp;
  32
  33        if (!str)
  34                return NULL;
  35        needlen = quote_c_style(str, NULL, NULL, 0);
  36        if (!needlen)
  37                return strdup(str);
  38        xp = xmalloc(needlen + 1);
  39        quote_c_style(str, xp, NULL, 0);
  40        return xp;
  41}
  42
  43static char *quote_two(const char *one, const char *two)
  44{
  45        int need_one = quote_c_style(one, NULL, NULL, 1);
  46        int need_two = quote_c_style(two, NULL, NULL, 1);
  47        char *xp;
  48
  49        if (need_one + need_two) {
  50                if (!need_one) need_one = strlen(one);
  51                if (!need_two) need_one = strlen(two);
  52
  53                xp = xmalloc(need_one + need_two + 3);
  54                xp[0] = '"';
  55                quote_c_style(one, xp + 1, NULL, 1);
  56                quote_c_style(two, xp + need_one + 1, NULL, 1);
  57                strcpy(xp + need_one + need_two + 1, "\"");
  58                return xp;
  59        }
  60        need_one = strlen(one);
  61        need_two = strlen(two);
  62        xp = xmalloc(need_one + need_two + 1);
  63        strcpy(xp, one);
  64        strcpy(xp + need_one, two);
  65        return xp;
  66}
  67
  68static const char *external_diff(void)
  69{
  70        static const char *external_diff_cmd = NULL;
  71        static int done_preparing = 0;
  72
  73        if (done_preparing)
  74                return external_diff_cmd;
  75        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
  76        done_preparing = 1;
  77        return external_diff_cmd;
  78}
  79
  80#define TEMPFILE_PATH_LEN               50
  81
  82static struct diff_tempfile {
  83        const char *name; /* filename external diff should read from */
  84        char hex[41];
  85        char mode[10];
  86        char tmp_path[TEMPFILE_PATH_LEN];
  87} diff_temp[2];
  88
  89static int count_lines(const char *data, int size)
  90{
  91        int count, ch, completely_empty = 1, nl_just_seen = 0;
  92        count = 0;
  93        while (0 < size--) {
  94                ch = *data++;
  95                if (ch == '\n') {
  96                        count++;
  97                        nl_just_seen = 1;
  98                        completely_empty = 0;
  99                }
 100                else {
 101                        nl_just_seen = 0;
 102                        completely_empty = 0;
 103                }
 104        }
 105        if (completely_empty)
 106                return 0;
 107        if (!nl_just_seen)
 108                count++; /* no trailing newline */
 109        return count;
 110}
 111
 112static void print_line_count(int count)
 113{
 114        switch (count) {
 115        case 0:
 116                printf("0,0");
 117                break;
 118        case 1:
 119                printf("1");
 120                break;
 121        default:
 122                printf("1,%d", count);
 123                break;
 124        }
 125}
 126
 127static void copy_file(int prefix, const char *data, int size)
 128{
 129        int ch, nl_just_seen = 1;
 130        while (0 < size--) {
 131                ch = *data++;
 132                if (nl_just_seen)
 133                        putchar(prefix);
 134                putchar(ch);
 135                if (ch == '\n')
 136                        nl_just_seen = 1;
 137                else
 138                        nl_just_seen = 0;
 139        }
 140        if (!nl_just_seen)
 141                printf("\n\\ No newline at end of file\n");
 142}
 143
 144static void emit_rewrite_diff(const char *name_a,
 145                              const char *name_b,
 146                              struct diff_filespec *one,
 147                              struct diff_filespec *two)
 148{
 149        int lc_a, lc_b;
 150        diff_populate_filespec(one, 0);
 151        diff_populate_filespec(two, 0);
 152        lc_a = count_lines(one->data, one->size);
 153        lc_b = count_lines(two->data, two->size);
 154        printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
 155        print_line_count(lc_a);
 156        printf(" +");
 157        print_line_count(lc_b);
 158        printf(" @@\n");
 159        if (lc_a)
 160                copy_file('-', one->data, one->size);
 161        if (lc_b)
 162                copy_file('+', two->data, two->size);
 163}
 164
 165static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 166{
 167        if (!DIFF_FILE_VALID(one)) {
 168                mf->ptr = ""; /* does not matter */
 169                mf->size = 0;
 170                return 0;
 171        }
 172        else if (diff_populate_filespec(one, 0))
 173                return -1;
 174        mf->ptr = one->data;
 175        mf->size = one->size;
 176        return 0;
 177}
 178
 179struct emit_callback {
 180        const char **label_path;
 181};
 182
 183static int fn_out(void *priv, mmbuffer_t *mb, int nbuf)
 184{
 185        int i;
 186        struct emit_callback *ecbdata = priv;
 187
 188        if (ecbdata->label_path[0]) {
 189                printf("--- %s\n", ecbdata->label_path[0]);
 190                printf("+++ %s\n", ecbdata->label_path[1]);
 191                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 192        }
 193        for (i = 0; i < nbuf; i++)
 194                if (!fwrite(mb[i].ptr, mb[i].size, 1, stdout))
 195                        return -1;
 196        return 0;
 197}
 198
 199static char *pprint_rename(const char *a, const char *b)
 200{
 201        const char *old = a;
 202        const char *new = b;
 203        char *name = NULL;
 204        int pfx_length, sfx_length;
 205        int len_a = strlen(a);
 206        int len_b = strlen(b);
 207
 208        /* Find common prefix */
 209        pfx_length = 0;
 210        while (*old && *new && *old == *new) {
 211                if (*old == '/')
 212                        pfx_length = old - a + 1;
 213                old++;
 214                new++;
 215        }
 216
 217        /* Find common suffix */
 218        old = a + len_a;
 219        new = b + len_b;
 220        sfx_length = 0;
 221        while (a <= old && b <= new && *old == *new) {
 222                if (*old == '/')
 223                        sfx_length = len_a - (old - a);
 224                old--;
 225                new--;
 226        }
 227
 228        /*
 229         * pfx{mid-a => mid-b}sfx
 230         * {pfx-a => pfx-b}sfx
 231         * pfx{sfx-a => sfx-b}
 232         * name-a => name-b
 233         */
 234        if (pfx_length + sfx_length) {
 235                name = xmalloc(len_a + len_b - pfx_length - sfx_length + 7);
 236                sprintf(name, "%.*s{%.*s => %.*s}%s",
 237                        pfx_length, a,
 238                        len_a - pfx_length - sfx_length, a + pfx_length,
 239                        len_b - pfx_length - sfx_length, b + pfx_length,
 240                        a + len_a - sfx_length);
 241        }
 242        else {
 243                name = xmalloc(len_a + len_b + 5);
 244                sprintf(name, "%s => %s", a, b);
 245        }
 246        return name;
 247}
 248
 249struct diffstat_t {
 250        struct xdiff_emit_state xm;
 251
 252        int nr;
 253        int alloc;
 254        struct diffstat_file {
 255                char *name;
 256                unsigned is_unmerged:1;
 257                unsigned is_binary:1;
 258                unsigned is_renamed:1;
 259                unsigned int added, deleted;
 260        } **files;
 261};
 262
 263static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 264                                          const char *name_a,
 265                                          const char *name_b)
 266{
 267        struct diffstat_file *x;
 268        x = xcalloc(sizeof (*x), 1);
 269        if (diffstat->nr == diffstat->alloc) {
 270                diffstat->alloc = alloc_nr(diffstat->alloc);
 271                diffstat->files = xrealloc(diffstat->files,
 272                                diffstat->alloc * sizeof(x));
 273        }
 274        diffstat->files[diffstat->nr++] = x;
 275        if (name_b) {
 276                x->name = pprint_rename(name_a, name_b);
 277                x->is_renamed = 1;
 278        }
 279        else
 280                x->name = strdup(name_a);
 281        return x;
 282}
 283
 284static void diffstat_consume(void *priv, char *line, unsigned long len)
 285{
 286        struct diffstat_t *diffstat = priv;
 287        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 288
 289        if (line[0] == '+')
 290                x->added++;
 291        else if (line[0] == '-')
 292                x->deleted++;
 293}
 294
 295static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
 296static const char minuses[]= "----------------------------------------------------------------------";
 297
 298static void show_stats(struct diffstat_t* data)
 299{
 300        char *prefix = "";
 301        int i, len, add, del, total, adds = 0, dels = 0;
 302        int max, max_change = 0, max_len = 0;
 303        int total_files = data->nr;
 304
 305        if (data->nr == 0)
 306                return;
 307
 308        for (i = 0; i < data->nr; i++) {
 309                struct diffstat_file *file = data->files[i];
 310
 311                len = strlen(file->name);
 312                if (max_len < len)
 313                        max_len = len;
 314
 315                if (file->is_binary || file->is_unmerged)
 316                        continue;
 317                if (max_change < file->added + file->deleted)
 318                        max_change = file->added + file->deleted;
 319        }
 320
 321        for (i = 0; i < data->nr; i++) {
 322                char *name = data->files[i]->name;
 323                int added = data->files[i]->added;
 324                int deleted = data->files[i]->deleted;
 325
 326                if (0 < (len = quote_c_style(name, NULL, NULL, 0))) {
 327                        char *qname = xmalloc(len + 1);
 328                        quote_c_style(name, qname, NULL, 0);
 329                        free(name);
 330                        data->files[i]->name = name = qname;
 331                }
 332
 333                /*
 334                 * "scale" the filename
 335                 */
 336                len = strlen(name);
 337                max = max_len;
 338                if (max > 50)
 339                        max = 50;
 340                if (len > max) {
 341                        char *slash;
 342                        prefix = "...";
 343                        max -= 3;
 344                        name += len - max;
 345                        slash = strchr(name, '/');
 346                        if (slash)
 347                                name = slash;
 348                }
 349                len = max;
 350
 351                /*
 352                 * scale the add/delete
 353                 */
 354                max = max_change;
 355                if (max + len > 70)
 356                        max = 70 - len;
 357
 358                if (data->files[i]->is_binary) {
 359                        printf(" %s%-*s |  Bin\n", prefix, len, name);
 360                        goto free_diffstat_file;
 361                }
 362                else if (data->files[i]->is_unmerged) {
 363                        printf(" %s%-*s |  Unmerged\n", prefix, len, name);
 364                        goto free_diffstat_file;
 365                }
 366                else if (!data->files[i]->is_renamed &&
 367                         (added + deleted == 0)) {
 368                        total_files--;
 369                        goto free_diffstat_file;
 370                }
 371
 372                add = added;
 373                del = deleted;
 374                total = add + del;
 375                adds += add;
 376                dels += del;
 377
 378                if (max_change > 0) {
 379                        total = (total * max + max_change / 2) / max_change;
 380                        add = (add * max + max_change / 2) / max_change;
 381                        del = total - add;
 382                }
 383                printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
 384                                len, name, added + deleted,
 385                                add, pluses, del, minuses);
 386        free_diffstat_file:
 387                free(data->files[i]->name);
 388                free(data->files[i]);
 389        }
 390        free(data->files);
 391        printf(" %d files changed, %d insertions(+), %d deletions(-)\n",
 392                        total_files, adds, dels);
 393}
 394
 395static void *encode_delta_size(void *data, unsigned long size)
 396{
 397        unsigned char *cp = data;
 398        *cp++ = size;
 399        size >>= 7;
 400        while (size) {
 401                cp[-1] |= 0x80;
 402                *cp++ = size;
 403                size >>= 7;
 404        }
 405        return cp;
 406}
 407
 408static void *safe_diff_delta(const unsigned char *src, unsigned long src_size,
 409                             const unsigned char *dst, unsigned long dst_size,
 410                             unsigned long *delta_size)
 411{
 412        unsigned long bufsize;
 413        unsigned char *data;
 414        unsigned char *cp;
 415
 416        if (src_size && dst_size)
 417                return diff_delta(src, src_size, dst, dst_size, delta_size, 0);
 418
 419        /* diff-delta does not like to do delta with empty, so
 420         * we do that by hand here.  Sigh...
 421         */
 422
 423        if (!src_size)
 424                /* literal copy can be done only 127-byte at a time.
 425                 */
 426                bufsize = dst_size + (dst_size / 127) + 40;
 427        else
 428                bufsize = 40;
 429        data = xmalloc(bufsize);
 430        cp = encode_delta_size(data, src_size);
 431        cp = encode_delta_size(cp, dst_size);
 432
 433        if (dst_size) {
 434                /* copy out literally */
 435                while (dst_size) {
 436                        int sz = (127 < dst_size) ? 127 : dst_size;
 437                        *cp++ = sz;
 438                        dst_size -= sz;
 439                        while (sz) {
 440                                *cp++ = *dst++;
 441                                sz--;
 442                        }
 443                }
 444        }
 445        *delta_size = (cp - data);
 446        return data;
 447}
 448
 449static void emit_binary_diff(mmfile_t *one, mmfile_t *two)
 450{
 451        void *delta, *cp;
 452        unsigned long delta_size;
 453
 454        printf("GIT binary patch\n");
 455        delta = safe_diff_delta(one->ptr, one->size,
 456                                two->ptr, two->size,
 457                                &delta_size);
 458        if (!delta)
 459                die("unable to generate binary diff");
 460
 461        /* emit delta encoded in base85 */
 462        cp = delta;
 463        while (delta_size) {
 464                int bytes = (52 < delta_size) ? 52 : delta_size;
 465                char line[70];
 466                delta_size -= bytes;
 467                if (bytes <= 26)
 468                        line[0] = bytes + 'A' - 1;
 469                else
 470                        line[0] = bytes - 26 + 'a' - 1;
 471                encode_85(line + 1, cp, bytes);
 472                cp += bytes;
 473                puts(line);
 474        }
 475        printf("\n");
 476        free(delta);
 477}
 478
 479#define FIRST_FEW_BYTES 8000
 480static int mmfile_is_binary(mmfile_t *mf)
 481{
 482        long sz = mf->size;
 483        if (FIRST_FEW_BYTES < sz)
 484                sz = FIRST_FEW_BYTES;
 485        if (memchr(mf->ptr, 0, sz))
 486                return 1;
 487        return 0;
 488}
 489
 490static void builtin_diff(const char *name_a,
 491                         const char *name_b,
 492                         struct diff_filespec *one,
 493                         struct diff_filespec *two,
 494                         const char *xfrm_msg,
 495                         struct diff_options *o,
 496                         int complete_rewrite)
 497{
 498        mmfile_t mf1, mf2;
 499        const char *lbl[2];
 500        char *a_one, *b_two;
 501
 502        a_one = quote_two("a/", name_a);
 503        b_two = quote_two("b/", name_b);
 504        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
 505        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
 506        printf("diff --git %s %s\n", a_one, b_two);
 507        if (lbl[0][0] == '/') {
 508                /* /dev/null */
 509                printf("new file mode %06o\n", two->mode);
 510                if (xfrm_msg && xfrm_msg[0])
 511                        puts(xfrm_msg);
 512        }
 513        else if (lbl[1][0] == '/') {
 514                printf("deleted file mode %06o\n", one->mode);
 515                if (xfrm_msg && xfrm_msg[0])
 516                        puts(xfrm_msg);
 517        }
 518        else {
 519                if (one->mode != two->mode) {
 520                        printf("old mode %06o\n", one->mode);
 521                        printf("new mode %06o\n", two->mode);
 522                }
 523                if (xfrm_msg && xfrm_msg[0])
 524                        puts(xfrm_msg);
 525                /*
 526                 * we do not run diff between different kind
 527                 * of objects.
 528                 */
 529                if ((one->mode ^ two->mode) & S_IFMT)
 530                        goto free_ab_and_return;
 531                if (complete_rewrite) {
 532                        emit_rewrite_diff(name_a, name_b, one, two);
 533                        goto free_ab_and_return;
 534                }
 535        }
 536
 537        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 538                die("unable to read files to diff");
 539
 540        if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2)) {
 541                if (o->full_index)
 542                        emit_binary_diff(&mf1, &mf2);
 543                else
 544                        printf("Binary files %s and %s differ\n",
 545                               lbl[0], lbl[1]);
 546        }
 547        else {
 548                /* Crazy xdl interfaces.. */
 549                const char *diffopts = getenv("GIT_DIFF_OPTS");
 550                xpparam_t xpp;
 551                xdemitconf_t xecfg;
 552                xdemitcb_t ecb;
 553                struct emit_callback ecbdata;
 554
 555                ecbdata.label_path = lbl;
 556                xpp.flags = XDF_NEED_MINIMAL;
 557                xecfg.ctxlen = 3;
 558                xecfg.flags = XDL_EMIT_FUNCNAMES;
 559                if (!diffopts)
 560                        ;
 561                else if (!strncmp(diffopts, "--unified=", 10))
 562                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
 563                else if (!strncmp(diffopts, "-u", 2))
 564                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
 565                ecb.outf = fn_out;
 566                ecb.priv = &ecbdata;
 567                xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 568        }
 569
 570 free_ab_and_return:
 571        free(a_one);
 572        free(b_two);
 573        return;
 574}
 575
 576static void builtin_diffstat(const char *name_a, const char *name_b,
 577                             struct diff_filespec *one,
 578                             struct diff_filespec *two,
 579                             struct diffstat_t *diffstat,
 580                             int complete_rewrite)
 581{
 582        mmfile_t mf1, mf2;
 583        struct diffstat_file *data;
 584
 585        data = diffstat_add(diffstat, name_a, name_b);
 586
 587        if (!one || !two) {
 588                data->is_unmerged = 1;
 589                return;
 590        }
 591        if (complete_rewrite) {
 592                diff_populate_filespec(one, 0);
 593                diff_populate_filespec(two, 0);
 594                data->deleted = count_lines(one->data, one->size);
 595                data->added = count_lines(two->data, two->size);
 596                return;
 597        }
 598        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 599                die("unable to read files to diff");
 600
 601        if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
 602                data->is_binary = 1;
 603        else {
 604                /* Crazy xdl interfaces.. */
 605                xpparam_t xpp;
 606                xdemitconf_t xecfg;
 607                xdemitcb_t ecb;
 608
 609                xpp.flags = XDF_NEED_MINIMAL;
 610                xecfg.ctxlen = 0;
 611                xecfg.flags = 0;
 612                ecb.outf = xdiff_outf;
 613                ecb.priv = diffstat;
 614                xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 615        }
 616}
 617
 618struct diff_filespec *alloc_filespec(const char *path)
 619{
 620        int namelen = strlen(path);
 621        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 622
 623        memset(spec, 0, sizeof(*spec));
 624        spec->path = (char *)(spec + 1);
 625        memcpy(spec->path, path, namelen+1);
 626        return spec;
 627}
 628
 629void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 630                   unsigned short mode)
 631{
 632        if (mode) {
 633                spec->mode = canon_mode(mode);
 634                memcpy(spec->sha1, sha1, 20);
 635                spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 636        }
 637}
 638
 639/*
 640 * Given a name and sha1 pair, if the dircache tells us the file in
 641 * the work tree has that object contents, return true, so that
 642 * prepare_temp_file() does not have to inflate and extract.
 643 */
 644static int work_tree_matches(const char *name, const unsigned char *sha1)
 645{
 646        struct cache_entry *ce;
 647        struct stat st;
 648        int pos, len;
 649
 650        /* We do not read the cache ourselves here, because the
 651         * benchmark with my previous version that always reads cache
 652         * shows that it makes things worse for diff-tree comparing
 653         * two linux-2.6 kernel trees in an already checked out work
 654         * tree.  This is because most diff-tree comparisons deal with
 655         * only a small number of files, while reading the cache is
 656         * expensive for a large project, and its cost outweighs the
 657         * savings we get by not inflating the object to a temporary
 658         * file.  Practically, this code only helps when we are used
 659         * by diff-cache --cached, which does read the cache before
 660         * calling us.
 661         */
 662        if (!active_cache)
 663                return 0;
 664
 665        len = strlen(name);
 666        pos = cache_name_pos(name, len);
 667        if (pos < 0)
 668                return 0;
 669        ce = active_cache[pos];
 670        if ((lstat(name, &st) < 0) ||
 671            !S_ISREG(st.st_mode) || /* careful! */
 672            ce_match_stat(ce, &st, 0) ||
 673            memcmp(sha1, ce->sha1, 20))
 674                return 0;
 675        /* we return 1 only when we can stat, it is a regular file,
 676         * stat information matches, and sha1 recorded in the cache
 677         * matches.  I.e. we know the file in the work tree really is
 678         * the same as the <name, sha1> pair.
 679         */
 680        return 1;
 681}
 682
 683static struct sha1_size_cache {
 684        unsigned char sha1[20];
 685        unsigned long size;
 686} **sha1_size_cache;
 687static int sha1_size_cache_nr, sha1_size_cache_alloc;
 688
 689static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
 690                                                 int find_only,
 691                                                 unsigned long size)
 692{
 693        int first, last;
 694        struct sha1_size_cache *e;
 695
 696        first = 0;
 697        last = sha1_size_cache_nr;
 698        while (last > first) {
 699                int cmp, next = (last + first) >> 1;
 700                e = sha1_size_cache[next];
 701                cmp = memcmp(e->sha1, sha1, 20);
 702                if (!cmp)
 703                        return e;
 704                if (cmp < 0) {
 705                        last = next;
 706                        continue;
 707                }
 708                first = next+1;
 709        }
 710        /* not found */
 711        if (find_only)
 712                return NULL;
 713        /* insert to make it at "first" */
 714        if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
 715                sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
 716                sha1_size_cache = xrealloc(sha1_size_cache,
 717                                           sha1_size_cache_alloc *
 718                                           sizeof(*sha1_size_cache));
 719        }
 720        sha1_size_cache_nr++;
 721        if (first < sha1_size_cache_nr)
 722                memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
 723                        (sha1_size_cache_nr - first - 1) *
 724                        sizeof(*sha1_size_cache));
 725        e = xmalloc(sizeof(struct sha1_size_cache));
 726        sha1_size_cache[first] = e;
 727        memcpy(e->sha1, sha1, 20);
 728        e->size = size;
 729        return e;
 730}
 731
 732/*
 733 * While doing rename detection and pickaxe operation, we may need to
 734 * grab the data for the blob (or file) for our own in-core comparison.
 735 * diff_filespec has data and size fields for this purpose.
 736 */
 737int diff_populate_filespec(struct diff_filespec *s, int size_only)
 738{
 739        int err = 0;
 740        if (!DIFF_FILE_VALID(s))
 741                die("internal error: asking to populate invalid file.");
 742        if (S_ISDIR(s->mode))
 743                return -1;
 744
 745        if (!use_size_cache)
 746                size_only = 0;
 747
 748        if (s->data)
 749                return err;
 750        if (!s->sha1_valid ||
 751            work_tree_matches(s->path, s->sha1)) {
 752                struct stat st;
 753                int fd;
 754                if (lstat(s->path, &st) < 0) {
 755                        if (errno == ENOENT) {
 756                        err_empty:
 757                                err = -1;
 758                        empty:
 759                                s->data = "";
 760                                s->size = 0;
 761                                return err;
 762                        }
 763                }
 764                s->size = st.st_size;
 765                if (!s->size)
 766                        goto empty;
 767                if (size_only)
 768                        return 0;
 769                if (S_ISLNK(st.st_mode)) {
 770                        int ret;
 771                        s->data = xmalloc(s->size);
 772                        s->should_free = 1;
 773                        ret = readlink(s->path, s->data, s->size);
 774                        if (ret < 0) {
 775                                free(s->data);
 776                                goto err_empty;
 777                        }
 778                        return 0;
 779                }
 780                fd = open(s->path, O_RDONLY);
 781                if (fd < 0)
 782                        goto err_empty;
 783                s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
 784                close(fd);
 785                if (s->data == MAP_FAILED)
 786                        goto err_empty;
 787                s->should_munmap = 1;
 788        }
 789        else {
 790                char type[20];
 791                struct sha1_size_cache *e;
 792
 793                if (size_only) {
 794                        e = locate_size_cache(s->sha1, 1, 0);
 795                        if (e) {
 796                                s->size = e->size;
 797                                return 0;
 798                        }
 799                        if (!sha1_object_info(s->sha1, type, &s->size))
 800                                locate_size_cache(s->sha1, 0, s->size);
 801                }
 802                else {
 803                        s->data = read_sha1_file(s->sha1, type, &s->size);
 804                        s->should_free = 1;
 805                }
 806        }
 807        return 0;
 808}
 809
 810void diff_free_filespec_data(struct diff_filespec *s)
 811{
 812        if (s->should_free)
 813                free(s->data);
 814        else if (s->should_munmap)
 815                munmap(s->data, s->size);
 816        s->should_free = s->should_munmap = 0;
 817        s->data = NULL;
 818        free(s->cnt_data);
 819        s->cnt_data = NULL;
 820}
 821
 822static void prep_temp_blob(struct diff_tempfile *temp,
 823                           void *blob,
 824                           unsigned long size,
 825                           const unsigned char *sha1,
 826                           int mode)
 827{
 828        int fd;
 829
 830        fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
 831        if (fd < 0)
 832                die("unable to create temp-file");
 833        if (write(fd, blob, size) != size)
 834                die("unable to write temp-file");
 835        close(fd);
 836        temp->name = temp->tmp_path;
 837        strcpy(temp->hex, sha1_to_hex(sha1));
 838        temp->hex[40] = 0;
 839        sprintf(temp->mode, "%06o", mode);
 840}
 841
 842static void prepare_temp_file(const char *name,
 843                              struct diff_tempfile *temp,
 844                              struct diff_filespec *one)
 845{
 846        if (!DIFF_FILE_VALID(one)) {
 847        not_a_valid_file:
 848                /* A '-' entry produces this for file-2, and
 849                 * a '+' entry produces this for file-1.
 850                 */
 851                temp->name = "/dev/null";
 852                strcpy(temp->hex, ".");
 853                strcpy(temp->mode, ".");
 854                return;
 855        }
 856
 857        if (!one->sha1_valid ||
 858            work_tree_matches(name, one->sha1)) {
 859                struct stat st;
 860                if (lstat(name, &st) < 0) {
 861                        if (errno == ENOENT)
 862                                goto not_a_valid_file;
 863                        die("stat(%s): %s", name, strerror(errno));
 864                }
 865                if (S_ISLNK(st.st_mode)) {
 866                        int ret;
 867                        char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
 868                        if (sizeof(buf) <= st.st_size)
 869                                die("symlink too long: %s", name);
 870                        ret = readlink(name, buf, st.st_size);
 871                        if (ret < 0)
 872                                die("readlink(%s)", name);
 873                        prep_temp_blob(temp, buf, st.st_size,
 874                                       (one->sha1_valid ?
 875                                        one->sha1 : null_sha1),
 876                                       (one->sha1_valid ?
 877                                        one->mode : S_IFLNK));
 878                }
 879                else {
 880                        /* we can borrow from the file in the work tree */
 881                        temp->name = name;
 882                        if (!one->sha1_valid)
 883                                strcpy(temp->hex, sha1_to_hex(null_sha1));
 884                        else
 885                                strcpy(temp->hex, sha1_to_hex(one->sha1));
 886                        /* Even though we may sometimes borrow the
 887                         * contents from the work tree, we always want
 888                         * one->mode.  mode is trustworthy even when
 889                         * !(one->sha1_valid), as long as
 890                         * DIFF_FILE_VALID(one).
 891                         */
 892                        sprintf(temp->mode, "%06o", one->mode);
 893                }
 894                return;
 895        }
 896        else {
 897                if (diff_populate_filespec(one, 0))
 898                        die("cannot read data blob for %s", one->path);
 899                prep_temp_blob(temp, one->data, one->size,
 900                               one->sha1, one->mode);
 901        }
 902}
 903
 904static void remove_tempfile(void)
 905{
 906        int i;
 907
 908        for (i = 0; i < 2; i++)
 909                if (diff_temp[i].name == diff_temp[i].tmp_path) {
 910                        unlink(diff_temp[i].name);
 911                        diff_temp[i].name = NULL;
 912                }
 913}
 914
 915static void remove_tempfile_on_signal(int signo)
 916{
 917        remove_tempfile();
 918        signal(SIGINT, SIG_DFL);
 919        raise(signo);
 920}
 921
 922static int spawn_prog(const char *pgm, const char **arg)
 923{
 924        pid_t pid;
 925        int status;
 926
 927        fflush(NULL);
 928        pid = fork();
 929        if (pid < 0)
 930                die("unable to fork");
 931        if (!pid) {
 932                execvp(pgm, (char *const*) arg);
 933                exit(255);
 934        }
 935
 936        while (waitpid(pid, &status, 0) < 0) {
 937                if (errno == EINTR)
 938                        continue;
 939                return -1;
 940        }
 941
 942        /* Earlier we did not check the exit status because
 943         * diff exits non-zero if files are different, and
 944         * we are not interested in knowing that.  It was a
 945         * mistake which made it harder to quit a diff-*
 946         * session that uses the git-apply-patch-script as
 947         * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 948         * should also exit non-zero only when it wants to
 949         * abort the entire diff-* session.
 950         */
 951        if (WIFEXITED(status) && !WEXITSTATUS(status))
 952                return 0;
 953        return -1;
 954}
 955
 956/* An external diff command takes:
 957 *
 958 * diff-cmd name infile1 infile1-sha1 infile1-mode \
 959 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 960 *
 961 */
 962static void run_external_diff(const char *pgm,
 963                              const char *name,
 964                              const char *other,
 965                              struct diff_filespec *one,
 966                              struct diff_filespec *two,
 967                              const char *xfrm_msg,
 968                              int complete_rewrite)
 969{
 970        const char *spawn_arg[10];
 971        struct diff_tempfile *temp = diff_temp;
 972        int retval;
 973        static int atexit_asked = 0;
 974        const char *othername;
 975        const char **arg = &spawn_arg[0];
 976
 977        othername = (other? other : name);
 978        if (one && two) {
 979                prepare_temp_file(name, &temp[0], one);
 980                prepare_temp_file(othername, &temp[1], two);
 981                if (! atexit_asked &&
 982                    (temp[0].name == temp[0].tmp_path ||
 983                     temp[1].name == temp[1].tmp_path)) {
 984                        atexit_asked = 1;
 985                        atexit(remove_tempfile);
 986                }
 987                signal(SIGINT, remove_tempfile_on_signal);
 988        }
 989
 990        if (one && two) {
 991                *arg++ = pgm;
 992                *arg++ = name;
 993                *arg++ = temp[0].name;
 994                *arg++ = temp[0].hex;
 995                *arg++ = temp[0].mode;
 996                *arg++ = temp[1].name;
 997                *arg++ = temp[1].hex;
 998                *arg++ = temp[1].mode;
 999                if (other) {
1000                        *arg++ = other;
1001                        *arg++ = xfrm_msg;
1002                }
1003        } else {
1004                *arg++ = pgm;
1005                *arg++ = name;
1006        }
1007        *arg = NULL;
1008        retval = spawn_prog(pgm, spawn_arg);
1009        remove_tempfile();
1010        if (retval) {
1011                fprintf(stderr, "external diff died, stopping at %s.\n", name);
1012                exit(1);
1013        }
1014}
1015
1016static void run_diff_cmd(const char *pgm,
1017                         const char *name,
1018                         const char *other,
1019                         struct diff_filespec *one,
1020                         struct diff_filespec *two,
1021                         const char *xfrm_msg,
1022                         struct diff_options *o,
1023                         int complete_rewrite)
1024{
1025        if (pgm) {
1026                run_external_diff(pgm, name, other, one, two, xfrm_msg,
1027                                  complete_rewrite);
1028                return;
1029        }
1030        if (one && two)
1031                builtin_diff(name, other ? other : name,
1032                             one, two, xfrm_msg, o, complete_rewrite);
1033        else
1034                printf("* Unmerged path %s\n", name);
1035}
1036
1037static void diff_fill_sha1_info(struct diff_filespec *one)
1038{
1039        if (DIFF_FILE_VALID(one)) {
1040                if (!one->sha1_valid) {
1041                        struct stat st;
1042                        if (lstat(one->path, &st) < 0)
1043                                die("stat %s", one->path);
1044                        if (index_path(one->sha1, one->path, &st, 0))
1045                                die("cannot hash %s\n", one->path);
1046                }
1047        }
1048        else
1049                memset(one->sha1, 0, 20);
1050}
1051
1052static void run_diff(struct diff_filepair *p, struct diff_options *o)
1053{
1054        const char *pgm = external_diff();
1055        char msg[PATH_MAX*2+300], *xfrm_msg;
1056        struct diff_filespec *one;
1057        struct diff_filespec *two;
1058        const char *name;
1059        const char *other;
1060        char *name_munged, *other_munged;
1061        int complete_rewrite = 0;
1062        int len;
1063
1064        if (DIFF_PAIR_UNMERGED(p)) {
1065                /* unmerged */
1066                run_diff_cmd(pgm, p->one->path, NULL, NULL, NULL, NULL, o, 0);
1067                return;
1068        }
1069
1070        name = p->one->path;
1071        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1072        name_munged = quote_one(name);
1073        other_munged = quote_one(other);
1074        one = p->one; two = p->two;
1075
1076        diff_fill_sha1_info(one);
1077        diff_fill_sha1_info(two);
1078
1079        len = 0;
1080        switch (p->status) {
1081        case DIFF_STATUS_COPIED:
1082                len += snprintf(msg + len, sizeof(msg) - len,
1083                                "similarity index %d%%\n"
1084                                "copy from %s\n"
1085                                "copy to %s\n",
1086                                (int)(0.5 + p->score * 100.0/MAX_SCORE),
1087                                name_munged, other_munged);
1088                break;
1089        case DIFF_STATUS_RENAMED:
1090                len += snprintf(msg + len, sizeof(msg) - len,
1091                                "similarity index %d%%\n"
1092                                "rename from %s\n"
1093                                "rename to %s\n",
1094                                (int)(0.5 + p->score * 100.0/MAX_SCORE),
1095                                name_munged, other_munged);
1096                break;
1097        case DIFF_STATUS_MODIFIED:
1098                if (p->score) {
1099                        len += snprintf(msg + len, sizeof(msg) - len,
1100                                        "dissimilarity index %d%%\n",
1101                                        (int)(0.5 + p->score *
1102                                              100.0/MAX_SCORE));
1103                        complete_rewrite = 1;
1104                        break;
1105                }
1106                /* fallthru */
1107        default:
1108                /* nothing */
1109                ;
1110        }
1111
1112        if (memcmp(one->sha1, two->sha1, 20)) {
1113                int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
1114
1115                len += snprintf(msg + len, sizeof(msg) - len,
1116                                "index %.*s..%.*s",
1117                                abbrev, sha1_to_hex(one->sha1),
1118                                abbrev, sha1_to_hex(two->sha1));
1119                if (one->mode == two->mode)
1120                        len += snprintf(msg + len, sizeof(msg) - len,
1121                                        " %06o", one->mode);
1122                len += snprintf(msg + len, sizeof(msg) - len, "\n");
1123        }
1124
1125        if (len)
1126                msg[--len] = 0;
1127        xfrm_msg = len ? msg : NULL;
1128
1129        if (!pgm &&
1130            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
1131            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
1132                /* a filepair that changes between file and symlink
1133                 * needs to be split into deletion and creation.
1134                 */
1135                struct diff_filespec *null = alloc_filespec(two->path);
1136                run_diff_cmd(NULL, name, other, one, null, xfrm_msg, o, 0);
1137                free(null);
1138                null = alloc_filespec(one->path);
1139                run_diff_cmd(NULL, name, other, null, two, xfrm_msg, o, 0);
1140                free(null);
1141        }
1142        else
1143                run_diff_cmd(pgm, name, other, one, two, xfrm_msg, o,
1144                             complete_rewrite);
1145
1146        free(name_munged);
1147        free(other_munged);
1148}
1149
1150static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
1151                         struct diffstat_t *diffstat)
1152{
1153        const char *name;
1154        const char *other;
1155        int complete_rewrite = 0;
1156
1157        if (DIFF_PAIR_UNMERGED(p)) {
1158                /* unmerged */
1159                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, 0);
1160                return;
1161        }
1162
1163        name = p->one->path;
1164        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1165
1166        diff_fill_sha1_info(p->one);
1167        diff_fill_sha1_info(p->two);
1168
1169        if (p->status == DIFF_STATUS_MODIFIED && p->score)
1170                complete_rewrite = 1;
1171        builtin_diffstat(name, other, p->one, p->two, diffstat, complete_rewrite);
1172}
1173
1174void diff_setup(struct diff_options *options)
1175{
1176        memset(options, 0, sizeof(*options));
1177        options->output_format = DIFF_FORMAT_RAW;
1178        options->line_termination = '\n';
1179        options->break_opt = -1;
1180        options->rename_limit = -1;
1181
1182        options->change = diff_change;
1183        options->add_remove = diff_addremove;
1184}
1185
1186int diff_setup_done(struct diff_options *options)
1187{
1188        if ((options->find_copies_harder &&
1189             options->detect_rename != DIFF_DETECT_COPY) ||
1190            (0 <= options->rename_limit && !options->detect_rename))
1191                return -1;
1192
1193        /*
1194         * These cases always need recursive; we do not drop caller-supplied
1195         * recursive bits for other formats here.
1196         */
1197        if ((options->output_format == DIFF_FORMAT_PATCH) ||
1198            (options->output_format == DIFF_FORMAT_DIFFSTAT))
1199                options->recursive = 1;
1200
1201        if (options->detect_rename && options->rename_limit < 0)
1202                options->rename_limit = diff_rename_limit_default;
1203        if (options->setup & DIFF_SETUP_USE_CACHE) {
1204                if (!active_cache)
1205                        /* read-cache does not die even when it fails
1206                         * so it is safe for us to do this here.  Also
1207                         * it does not smudge active_cache or active_nr
1208                         * when it fails, so we do not have to worry about
1209                         * cleaning it up ourselves either.
1210                         */
1211                        read_cache();
1212        }
1213        if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
1214                use_size_cache = 1;
1215        if (options->abbrev <= 0 || 40 < options->abbrev)
1216                options->abbrev = 40; /* full */
1217
1218        return 0;
1219}
1220
1221int diff_opt_parse(struct diff_options *options, const char **av, int ac)
1222{
1223        const char *arg = av[0];
1224        if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
1225                options->output_format = DIFF_FORMAT_PATCH;
1226        else if (!strcmp(arg, "--patch-with-raw")) {
1227                options->output_format = DIFF_FORMAT_PATCH;
1228                options->with_raw = 1;
1229        }
1230        else if (!strcmp(arg, "--stat"))
1231                options->output_format = DIFF_FORMAT_DIFFSTAT;
1232        else if (!strcmp(arg, "--patch-with-stat")) {
1233                options->output_format = DIFF_FORMAT_PATCH;
1234                options->with_stat = 1;
1235        }
1236        else if (!strcmp(arg, "-z"))
1237                options->line_termination = 0;
1238        else if (!strncmp(arg, "-l", 2))
1239                options->rename_limit = strtoul(arg+2, NULL, 10);
1240        else if (!strcmp(arg, "--full-index"))
1241                options->full_index = 1;
1242        else if (!strcmp(arg, "--name-only"))
1243                options->output_format = DIFF_FORMAT_NAME;
1244        else if (!strcmp(arg, "--name-status"))
1245                options->output_format = DIFF_FORMAT_NAME_STATUS;
1246        else if (!strcmp(arg, "-R"))
1247                options->reverse_diff = 1;
1248        else if (!strncmp(arg, "-S", 2))
1249                options->pickaxe = arg + 2;
1250        else if (!strcmp(arg, "-s"))
1251                options->output_format = DIFF_FORMAT_NO_OUTPUT;
1252        else if (!strncmp(arg, "-O", 2))
1253                options->orderfile = arg + 2;
1254        else if (!strncmp(arg, "--diff-filter=", 14))
1255                options->filter = arg + 14;
1256        else if (!strcmp(arg, "--pickaxe-all"))
1257                options->pickaxe_opts = DIFF_PICKAXE_ALL;
1258        else if (!strcmp(arg, "--pickaxe-regex"))
1259                options->pickaxe_opts = DIFF_PICKAXE_REGEX;
1260        else if (!strncmp(arg, "-B", 2)) {
1261                if ((options->break_opt =
1262                     diff_scoreopt_parse(arg)) == -1)
1263                        return -1;
1264        }
1265        else if (!strncmp(arg, "-M", 2)) {
1266                if ((options->rename_score =
1267                     diff_scoreopt_parse(arg)) == -1)
1268                        return -1;
1269                options->detect_rename = DIFF_DETECT_RENAME;
1270        }
1271        else if (!strncmp(arg, "-C", 2)) {
1272                if ((options->rename_score =
1273                     diff_scoreopt_parse(arg)) == -1)
1274                        return -1;
1275                options->detect_rename = DIFF_DETECT_COPY;
1276        }
1277        else if (!strcmp(arg, "--find-copies-harder"))
1278                options->find_copies_harder = 1;
1279        else if (!strcmp(arg, "--abbrev"))
1280                options->abbrev = DEFAULT_ABBREV;
1281        else if (!strncmp(arg, "--abbrev=", 9)) {
1282                options->abbrev = strtoul(arg + 9, NULL, 10);
1283                if (options->abbrev < MINIMUM_ABBREV)
1284                        options->abbrev = MINIMUM_ABBREV;
1285                else if (40 < options->abbrev)
1286                        options->abbrev = 40;
1287        }
1288        else
1289                return 0;
1290        return 1;
1291}
1292
1293static int parse_num(const char **cp_p)
1294{
1295        unsigned long num, scale;
1296        int ch, dot;
1297        const char *cp = *cp_p;
1298
1299        num = 0;
1300        scale = 1;
1301        dot = 0;
1302        for(;;) {
1303                ch = *cp;
1304                if ( !dot && ch == '.' ) {
1305                        scale = 1;
1306                        dot = 1;
1307                } else if ( ch == '%' ) {
1308                        scale = dot ? scale*100 : 100;
1309                        cp++;   /* % is always at the end */
1310                        break;
1311                } else if ( ch >= '0' && ch <= '9' ) {
1312                        if ( scale < 100000 ) {
1313                                scale *= 10;
1314                                num = (num*10) + (ch-'0');
1315                        }
1316                } else {
1317                        break;
1318                }
1319                cp++;
1320        }
1321        *cp_p = cp;
1322
1323        /* user says num divided by scale and we say internally that
1324         * is MAX_SCORE * num / scale.
1325         */
1326        return (num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale);
1327}
1328
1329int diff_scoreopt_parse(const char *opt)
1330{
1331        int opt1, opt2, cmd;
1332
1333        if (*opt++ != '-')
1334                return -1;
1335        cmd = *opt++;
1336        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
1337                return -1; /* that is not a -M, -C nor -B option */
1338
1339        opt1 = parse_num(&opt);
1340        if (cmd != 'B')
1341                opt2 = 0;
1342        else {
1343                if (*opt == 0)
1344                        opt2 = 0;
1345                else if (*opt != '/')
1346                        return -1; /* we expect -B80/99 or -B80 */
1347                else {
1348                        opt++;
1349                        opt2 = parse_num(&opt);
1350                }
1351        }
1352        if (*opt != 0)
1353                return -1;
1354        return opt1 | (opt2 << 16);
1355}
1356
1357struct diff_queue_struct diff_queued_diff;
1358
1359void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
1360{
1361        if (queue->alloc <= queue->nr) {
1362                queue->alloc = alloc_nr(queue->alloc);
1363                queue->queue = xrealloc(queue->queue,
1364                                        sizeof(dp) * queue->alloc);
1365        }
1366        queue->queue[queue->nr++] = dp;
1367}
1368
1369struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
1370                                 struct diff_filespec *one,
1371                                 struct diff_filespec *two)
1372{
1373        struct diff_filepair *dp = xmalloc(sizeof(*dp));
1374        dp->one = one;
1375        dp->two = two;
1376        dp->score = 0;
1377        dp->status = 0;
1378        dp->source_stays = 0;
1379        dp->broken_pair = 0;
1380        if (queue)
1381                diff_q(queue, dp);
1382        return dp;
1383}
1384
1385void diff_free_filepair(struct diff_filepair *p)
1386{
1387        diff_free_filespec_data(p->one);
1388        diff_free_filespec_data(p->two);
1389        free(p->one);
1390        free(p->two);
1391        free(p);
1392}
1393
1394/* This is different from find_unique_abbrev() in that
1395 * it stuffs the result with dots for alignment.
1396 */
1397const char *diff_unique_abbrev(const unsigned char *sha1, int len)
1398{
1399        int abblen;
1400        const char *abbrev;
1401        if (len == 40)
1402                return sha1_to_hex(sha1);
1403
1404        abbrev = find_unique_abbrev(sha1, len);
1405        if (!abbrev)
1406                return sha1_to_hex(sha1);
1407        abblen = strlen(abbrev);
1408        if (abblen < 37) {
1409                static char hex[41];
1410                if (len < abblen && abblen <= len + 2)
1411                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
1412                else
1413                        sprintf(hex, "%s...", abbrev);
1414                return hex;
1415        }
1416        return sha1_to_hex(sha1);
1417}
1418
1419static void diff_flush_raw(struct diff_filepair *p,
1420                           int line_termination,
1421                           int inter_name_termination,
1422                           struct diff_options *options,
1423                           int output_format)
1424{
1425        int two_paths;
1426        char status[10];
1427        int abbrev = options->abbrev;
1428        const char *path_one, *path_two;
1429
1430        path_one = p->one->path;
1431        path_two = p->two->path;
1432        if (line_termination) {
1433                path_one = quote_one(path_one);
1434                path_two = quote_one(path_two);
1435        }
1436
1437        if (p->score)
1438                sprintf(status, "%c%03d", p->status,
1439                        (int)(0.5 + p->score * 100.0/MAX_SCORE));
1440        else {
1441                status[0] = p->status;
1442                status[1] = 0;
1443        }
1444        switch (p->status) {
1445        case DIFF_STATUS_COPIED:
1446        case DIFF_STATUS_RENAMED:
1447                two_paths = 1;
1448                break;
1449        case DIFF_STATUS_ADDED:
1450        case DIFF_STATUS_DELETED:
1451                two_paths = 0;
1452                break;
1453        default:
1454                two_paths = 0;
1455                break;
1456        }
1457        if (output_format != DIFF_FORMAT_NAME_STATUS) {
1458                printf(":%06o %06o %s ",
1459                       p->one->mode, p->two->mode,
1460                       diff_unique_abbrev(p->one->sha1, abbrev));
1461                printf("%s ",
1462                       diff_unique_abbrev(p->two->sha1, abbrev));
1463        }
1464        printf("%s%c%s", status, inter_name_termination, path_one);
1465        if (two_paths)
1466                printf("%c%s", inter_name_termination, path_two);
1467        putchar(line_termination);
1468        if (path_one != p->one->path)
1469                free((void*)path_one);
1470        if (path_two != p->two->path)
1471                free((void*)path_two);
1472}
1473
1474static void diff_flush_name(struct diff_filepair *p,
1475                            int inter_name_termination,
1476                            int line_termination)
1477{
1478        char *path = p->two->path;
1479
1480        if (line_termination)
1481                path = quote_one(p->two->path);
1482        else
1483                path = p->two->path;
1484        printf("%s%c", path, line_termination);
1485        if (p->two->path != path)
1486                free(path);
1487}
1488
1489int diff_unmodified_pair(struct diff_filepair *p)
1490{
1491        /* This function is written stricter than necessary to support
1492         * the currently implemented transformers, but the idea is to
1493         * let transformers to produce diff_filepairs any way they want,
1494         * and filter and clean them up here before producing the output.
1495         */
1496        struct diff_filespec *one, *two;
1497
1498        if (DIFF_PAIR_UNMERGED(p))
1499                return 0; /* unmerged is interesting */
1500
1501        one = p->one;
1502        two = p->two;
1503
1504        /* deletion, addition, mode or type change
1505         * and rename are all interesting.
1506         */
1507        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
1508            DIFF_PAIR_MODE_CHANGED(p) ||
1509            strcmp(one->path, two->path))
1510                return 0;
1511
1512        /* both are valid and point at the same path.  that is, we are
1513         * dealing with a change.
1514         */
1515        if (one->sha1_valid && two->sha1_valid &&
1516            !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
1517                return 1; /* no change */
1518        if (!one->sha1_valid && !two->sha1_valid)
1519                return 1; /* both look at the same file on the filesystem. */
1520        return 0;
1521}
1522
1523static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
1524{
1525        if (diff_unmodified_pair(p))
1526                return;
1527
1528        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1529            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1530                return; /* no tree diffs in patch format */
1531
1532        run_diff(p, o);
1533}
1534
1535static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
1536                            struct diffstat_t *diffstat)
1537{
1538        if (diff_unmodified_pair(p))
1539                return;
1540
1541        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1542            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1543                return; /* no tree diffs in patch format */
1544
1545        run_diffstat(p, o, diffstat);
1546}
1547
1548int diff_queue_is_empty(void)
1549{
1550        struct diff_queue_struct *q = &diff_queued_diff;
1551        int i;
1552        for (i = 0; i < q->nr; i++)
1553                if (!diff_unmodified_pair(q->queue[i]))
1554                        return 0;
1555        return 1;
1556}
1557
1558#if DIFF_DEBUG
1559void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
1560{
1561        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
1562                x, one ? one : "",
1563                s->path,
1564                DIFF_FILE_VALID(s) ? "valid" : "invalid",
1565                s->mode,
1566                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
1567        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
1568                x, one ? one : "",
1569                s->size, s->xfrm_flags);
1570}
1571
1572void diff_debug_filepair(const struct diff_filepair *p, int i)
1573{
1574        diff_debug_filespec(p->one, i, "one");
1575        diff_debug_filespec(p->two, i, "two");
1576        fprintf(stderr, "score %d, status %c stays %d broken %d\n",
1577                p->score, p->status ? p->status : '?',
1578                p->source_stays, p->broken_pair);
1579}
1580
1581void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
1582{
1583        int i;
1584        if (msg)
1585                fprintf(stderr, "%s\n", msg);
1586        fprintf(stderr, "q->nr = %d\n", q->nr);
1587        for (i = 0; i < q->nr; i++) {
1588                struct diff_filepair *p = q->queue[i];
1589                diff_debug_filepair(p, i);
1590        }
1591}
1592#endif
1593
1594static void diff_resolve_rename_copy(void)
1595{
1596        int i, j;
1597        struct diff_filepair *p, *pp;
1598        struct diff_queue_struct *q = &diff_queued_diff;
1599
1600        diff_debug_queue("resolve-rename-copy", q);
1601
1602        for (i = 0; i < q->nr; i++) {
1603                p = q->queue[i];
1604                p->status = 0; /* undecided */
1605                if (DIFF_PAIR_UNMERGED(p))
1606                        p->status = DIFF_STATUS_UNMERGED;
1607                else if (!DIFF_FILE_VALID(p->one))
1608                        p->status = DIFF_STATUS_ADDED;
1609                else if (!DIFF_FILE_VALID(p->two))
1610                        p->status = DIFF_STATUS_DELETED;
1611                else if (DIFF_PAIR_TYPE_CHANGED(p))
1612                        p->status = DIFF_STATUS_TYPE_CHANGED;
1613
1614                /* from this point on, we are dealing with a pair
1615                 * whose both sides are valid and of the same type, i.e.
1616                 * either in-place edit or rename/copy edit.
1617                 */
1618                else if (DIFF_PAIR_RENAME(p)) {
1619                        if (p->source_stays) {
1620                                p->status = DIFF_STATUS_COPIED;
1621                                continue;
1622                        }
1623                        /* See if there is some other filepair that
1624                         * copies from the same source as us.  If so
1625                         * we are a copy.  Otherwise we are either a
1626                         * copy if the path stays, or a rename if it
1627                         * does not, but we already handled "stays" case.
1628                         */
1629                        for (j = i + 1; j < q->nr; j++) {
1630                                pp = q->queue[j];
1631                                if (strcmp(pp->one->path, p->one->path))
1632                                        continue; /* not us */
1633                                if (!DIFF_PAIR_RENAME(pp))
1634                                        continue; /* not a rename/copy */
1635                                /* pp is a rename/copy from the same source */
1636                                p->status = DIFF_STATUS_COPIED;
1637                                break;
1638                        }
1639                        if (!p->status)
1640                                p->status = DIFF_STATUS_RENAMED;
1641                }
1642                else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
1643                         p->one->mode != p->two->mode)
1644                        p->status = DIFF_STATUS_MODIFIED;
1645                else {
1646                        /* This is a "no-change" entry and should not
1647                         * happen anymore, but prepare for broken callers.
1648                         */
1649                        error("feeding unmodified %s to diffcore",
1650                              p->one->path);
1651                        p->status = DIFF_STATUS_UNKNOWN;
1652                }
1653        }
1654        diff_debug_queue("resolve-rename-copy done", q);
1655}
1656
1657static void flush_one_pair(struct diff_filepair *p,
1658                           int diff_output_format,
1659                           struct diff_options *options,
1660                           struct diffstat_t *diffstat)
1661{
1662        int inter_name_termination = '\t';
1663        int line_termination = options->line_termination;
1664        if (!line_termination)
1665                inter_name_termination = 0;
1666
1667        switch (p->status) {
1668        case DIFF_STATUS_UNKNOWN:
1669                break;
1670        case 0:
1671                die("internal error in diff-resolve-rename-copy");
1672                break;
1673        default:
1674                switch (diff_output_format) {
1675                case DIFF_FORMAT_DIFFSTAT:
1676                        diff_flush_stat(p, options, diffstat);
1677                        break;
1678                case DIFF_FORMAT_PATCH:
1679                        diff_flush_patch(p, options);
1680                        break;
1681                case DIFF_FORMAT_RAW:
1682                case DIFF_FORMAT_NAME_STATUS:
1683                        diff_flush_raw(p, line_termination,
1684                                       inter_name_termination,
1685                                       options, diff_output_format);
1686                        break;
1687                case DIFF_FORMAT_NAME:
1688                        diff_flush_name(p,
1689                                        inter_name_termination,
1690                                        line_termination);
1691                        break;
1692                case DIFF_FORMAT_NO_OUTPUT:
1693                        break;
1694                }
1695        }
1696}
1697
1698void diff_flush(struct diff_options *options)
1699{
1700        struct diff_queue_struct *q = &diff_queued_diff;
1701        int i;
1702        int diff_output_format = options->output_format;
1703        struct diffstat_t *diffstat = NULL;
1704
1705        if (diff_output_format == DIFF_FORMAT_DIFFSTAT || options->with_stat) {
1706                diffstat = xcalloc(sizeof (struct diffstat_t), 1);
1707                diffstat->xm.consume = diffstat_consume;
1708        }
1709
1710        if (options->with_raw) {
1711                for (i = 0; i < q->nr; i++) {
1712                        struct diff_filepair *p = q->queue[i];
1713                        flush_one_pair(p, DIFF_FORMAT_RAW, options, NULL);
1714                }
1715                putchar(options->line_termination);
1716        }
1717        if (options->with_stat) {
1718                for (i = 0; i < q->nr; i++) {
1719                        struct diff_filepair *p = q->queue[i];
1720                        flush_one_pair(p, DIFF_FORMAT_DIFFSTAT, options,
1721                                       diffstat);
1722                }
1723                show_stats(diffstat);
1724                free(diffstat);
1725                diffstat = NULL;
1726                putchar(options->line_termination);
1727        }
1728        for (i = 0; i < q->nr; i++) {
1729                struct diff_filepair *p = q->queue[i];
1730                flush_one_pair(p, diff_output_format, options, diffstat);
1731                diff_free_filepair(p);
1732        }
1733
1734        if (diffstat) {
1735                show_stats(diffstat);
1736                free(diffstat);
1737        }
1738
1739        free(q->queue);
1740        q->queue = NULL;
1741        q->nr = q->alloc = 0;
1742}
1743
1744static void diffcore_apply_filter(const char *filter)
1745{
1746        int i;
1747        struct diff_queue_struct *q = &diff_queued_diff;
1748        struct diff_queue_struct outq;
1749        outq.queue = NULL;
1750        outq.nr = outq.alloc = 0;
1751
1752        if (!filter)
1753                return;
1754
1755        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
1756                int found;
1757                for (i = found = 0; !found && i < q->nr; i++) {
1758                        struct diff_filepair *p = q->queue[i];
1759                        if (((p->status == DIFF_STATUS_MODIFIED) &&
1760                             ((p->score &&
1761                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1762                              (!p->score &&
1763                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1764                            ((p->status != DIFF_STATUS_MODIFIED) &&
1765                             strchr(filter, p->status)))
1766                                found++;
1767                }
1768                if (found)
1769                        return;
1770
1771                /* otherwise we will clear the whole queue
1772                 * by copying the empty outq at the end of this
1773                 * function, but first clear the current entries
1774                 * in the queue.
1775                 */
1776                for (i = 0; i < q->nr; i++)
1777                        diff_free_filepair(q->queue[i]);
1778        }
1779        else {
1780                /* Only the matching ones */
1781                for (i = 0; i < q->nr; i++) {
1782                        struct diff_filepair *p = q->queue[i];
1783
1784                        if (((p->status == DIFF_STATUS_MODIFIED) &&
1785                             ((p->score &&
1786                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1787                              (!p->score &&
1788                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1789                            ((p->status != DIFF_STATUS_MODIFIED) &&
1790                             strchr(filter, p->status)))
1791                                diff_q(&outq, p);
1792                        else
1793                                diff_free_filepair(p);
1794                }
1795        }
1796        free(q->queue);
1797        *q = outq;
1798}
1799
1800void diffcore_std(struct diff_options *options)
1801{
1802        if (options->break_opt != -1)
1803                diffcore_break(options->break_opt);
1804        if (options->detect_rename)
1805                diffcore_rename(options);
1806        if (options->break_opt != -1)
1807                diffcore_merge_broken();
1808        if (options->pickaxe)
1809                diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1810        if (options->orderfile)
1811                diffcore_order(options->orderfile);
1812        diff_resolve_rename_copy();
1813        diffcore_apply_filter(options->filter);
1814}
1815
1816
1817void diffcore_std_no_resolve(struct diff_options *options)
1818{
1819        if (options->pickaxe)
1820                diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1821        if (options->orderfile)
1822                diffcore_order(options->orderfile);
1823        diffcore_apply_filter(options->filter);
1824}
1825
1826void diff_addremove(struct diff_options *options,
1827                    int addremove, unsigned mode,
1828                    const unsigned char *sha1,
1829                    const char *base, const char *path)
1830{
1831        char concatpath[PATH_MAX];
1832        struct diff_filespec *one, *two;
1833
1834        /* This may look odd, but it is a preparation for
1835         * feeding "there are unchanged files which should
1836         * not produce diffs, but when you are doing copy
1837         * detection you would need them, so here they are"
1838         * entries to the diff-core.  They will be prefixed
1839         * with something like '=' or '*' (I haven't decided
1840         * which but should not make any difference).
1841         * Feeding the same new and old to diff_change() 
1842         * also has the same effect.
1843         * Before the final output happens, they are pruned after
1844         * merged into rename/copy pairs as appropriate.
1845         */
1846        if (options->reverse_diff)
1847                addremove = (addremove == '+' ? '-' :
1848                             addremove == '-' ? '+' : addremove);
1849
1850        if (!path) path = "";
1851        sprintf(concatpath, "%s%s", base, path);
1852        one = alloc_filespec(concatpath);
1853        two = alloc_filespec(concatpath);
1854
1855        if (addremove != '+')
1856                fill_filespec(one, sha1, mode);
1857        if (addremove != '-')
1858                fill_filespec(two, sha1, mode);
1859
1860        diff_queue(&diff_queued_diff, one, two);
1861}
1862
1863void diff_change(struct diff_options *options,
1864                 unsigned old_mode, unsigned new_mode,
1865                 const unsigned char *old_sha1,
1866                 const unsigned char *new_sha1,
1867                 const char *base, const char *path) 
1868{
1869        char concatpath[PATH_MAX];
1870        struct diff_filespec *one, *two;
1871
1872        if (options->reverse_diff) {
1873                unsigned tmp;
1874                const unsigned char *tmp_c;
1875                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1876                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1877        }
1878        if (!path) path = "";
1879        sprintf(concatpath, "%s%s", base, path);
1880        one = alloc_filespec(concatpath);
1881        two = alloc_filespec(concatpath);
1882        fill_filespec(one, old_sha1, old_mode);
1883        fill_filespec(two, new_sha1, new_mode);
1884
1885        diff_queue(&diff_queued_diff, one, two);
1886}
1887
1888void diff_unmerge(struct diff_options *options,
1889                  const char *path)
1890{
1891        struct diff_filespec *one, *two;
1892        one = alloc_filespec(path);
1893        two = alloc_filespec(path);
1894        diff_queue(&diff_queued_diff, one, two);
1895}