0c69354d0a950fe87ab7c0deef16484ac97e987d
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18
  19#ifdef NO_FAST_WORKING_DIRECTORY
  20#define FAST_WORKING_DIRECTORY 0
  21#else
  22#define FAST_WORKING_DIRECTORY 1
  23#endif
  24
  25static int diff_detect_rename_default;
  26static int diff_rename_limit_default = 400;
  27static int diff_suppress_blank_empty;
  28int diff_use_color_default = -1;
  29static const char *diff_word_regex_cfg;
  30static const char *external_diff_cmd_cfg;
  31int diff_auto_refresh_index = 1;
  32static int diff_mnemonic_prefix;
  33static int diff_no_prefix;
  34static struct diff_options default_diff_options;
  35
  36static char diff_colors[][COLOR_MAXLEN] = {
  37        GIT_COLOR_RESET,
  38        GIT_COLOR_NORMAL,       /* PLAIN */
  39        GIT_COLOR_BOLD,         /* METAINFO */
  40        GIT_COLOR_CYAN,         /* FRAGINFO */
  41        GIT_COLOR_RED,          /* OLD */
  42        GIT_COLOR_GREEN,        /* NEW */
  43        GIT_COLOR_YELLOW,       /* COMMIT */
  44        GIT_COLOR_BG_RED,       /* WHITESPACE */
  45        GIT_COLOR_NORMAL,       /* FUNCINFO */
  46};
  47
  48static int parse_diff_color_slot(const char *var, int ofs)
  49{
  50        if (!strcasecmp(var+ofs, "plain"))
  51                return DIFF_PLAIN;
  52        if (!strcasecmp(var+ofs, "meta"))
  53                return DIFF_METAINFO;
  54        if (!strcasecmp(var+ofs, "frag"))
  55                return DIFF_FRAGINFO;
  56        if (!strcasecmp(var+ofs, "old"))
  57                return DIFF_FILE_OLD;
  58        if (!strcasecmp(var+ofs, "new"))
  59                return DIFF_FILE_NEW;
  60        if (!strcasecmp(var+ofs, "commit"))
  61                return DIFF_COMMIT;
  62        if (!strcasecmp(var+ofs, "whitespace"))
  63                return DIFF_WHITESPACE;
  64        if (!strcasecmp(var+ofs, "func"))
  65                return DIFF_FUNCINFO;
  66        return -1;
  67}
  68
  69static int git_config_rename(const char *var, const char *value)
  70{
  71        if (!value)
  72                return DIFF_DETECT_RENAME;
  73        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
  74                return  DIFF_DETECT_COPY;
  75        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
  76}
  77
  78/*
  79 * These are to give UI layer defaults.
  80 * The core-level commands such as git-diff-files should
  81 * never be affected by the setting of diff.renames
  82 * the user happens to have in the configuration file.
  83 */
  84int git_diff_ui_config(const char *var, const char *value, void *cb)
  85{
  86        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
  87                diff_use_color_default = git_config_colorbool(var, value, -1);
  88                return 0;
  89        }
  90        if (!strcmp(var, "diff.renames")) {
  91                diff_detect_rename_default = git_config_rename(var, value);
  92                return 0;
  93        }
  94        if (!strcmp(var, "diff.autorefreshindex")) {
  95                diff_auto_refresh_index = git_config_bool(var, value);
  96                return 0;
  97        }
  98        if (!strcmp(var, "diff.mnemonicprefix")) {
  99                diff_mnemonic_prefix = git_config_bool(var, value);
 100                return 0;
 101        }
 102        if (!strcmp(var, "diff.noprefix")) {
 103                diff_no_prefix = git_config_bool(var, value);
 104                return 0;
 105        }
 106        if (!strcmp(var, "diff.external"))
 107                return git_config_string(&external_diff_cmd_cfg, var, value);
 108        if (!strcmp(var, "diff.wordregex"))
 109                return git_config_string(&diff_word_regex_cfg, var, value);
 110
 111        if (!strcmp(var, "diff.ignoresubmodules"))
 112                handle_ignore_submodules_arg(&default_diff_options, value);
 113
 114        return git_diff_basic_config(var, value, cb);
 115}
 116
 117int git_diff_basic_config(const char *var, const char *value, void *cb)
 118{
 119        if (!strcmp(var, "diff.renamelimit")) {
 120                diff_rename_limit_default = git_config_int(var, value);
 121                return 0;
 122        }
 123
 124        switch (userdiff_config(var, value)) {
 125                case 0: break;
 126                case -1: return -1;
 127                default: return 0;
 128        }
 129
 130        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 131                int slot = parse_diff_color_slot(var, 11);
 132                if (slot < 0)
 133                        return 0;
 134                if (!value)
 135                        return config_error_nonbool(var);
 136                color_parse(value, var, diff_colors[slot]);
 137                return 0;
 138        }
 139
 140        /* like GNU diff's --suppress-blank-empty option  */
 141        if (!strcmp(var, "diff.suppressblankempty") ||
 142                        /* for backwards compatibility */
 143                        !strcmp(var, "diff.suppress-blank-empty")) {
 144                diff_suppress_blank_empty = git_config_bool(var, value);
 145                return 0;
 146        }
 147
 148        if (!prefixcmp(var, "submodule."))
 149                return parse_submodule_config_option(var, value);
 150
 151        return git_color_default_config(var, value, cb);
 152}
 153
 154static char *quote_two(const char *one, const char *two)
 155{
 156        int need_one = quote_c_style(one, NULL, NULL, 1);
 157        int need_two = quote_c_style(two, NULL, NULL, 1);
 158        struct strbuf res = STRBUF_INIT;
 159
 160        if (need_one + need_two) {
 161                strbuf_addch(&res, '"');
 162                quote_c_style(one, &res, NULL, 1);
 163                quote_c_style(two, &res, NULL, 1);
 164                strbuf_addch(&res, '"');
 165        } else {
 166                strbuf_addstr(&res, one);
 167                strbuf_addstr(&res, two);
 168        }
 169        return strbuf_detach(&res, NULL);
 170}
 171
 172static const char *external_diff(void)
 173{
 174        static const char *external_diff_cmd = NULL;
 175        static int done_preparing = 0;
 176
 177        if (done_preparing)
 178                return external_diff_cmd;
 179        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 180        if (!external_diff_cmd)
 181                external_diff_cmd = external_diff_cmd_cfg;
 182        done_preparing = 1;
 183        return external_diff_cmd;
 184}
 185
 186static struct diff_tempfile {
 187        const char *name; /* filename external diff should read from */
 188        char hex[41];
 189        char mode[10];
 190        char tmp_path[PATH_MAX];
 191} diff_temp[2];
 192
 193typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 194
 195struct emit_callback {
 196        int color_diff;
 197        unsigned ws_rule;
 198        int blank_at_eof_in_preimage;
 199        int blank_at_eof_in_postimage;
 200        int lno_in_preimage;
 201        int lno_in_postimage;
 202        sane_truncate_fn truncate;
 203        const char **label_path;
 204        struct diff_words_data *diff_words;
 205        struct diff_options *opt;
 206        int *found_changesp;
 207        struct strbuf *header;
 208};
 209
 210static int count_lines(const char *data, int size)
 211{
 212        int count, ch, completely_empty = 1, nl_just_seen = 0;
 213        count = 0;
 214        while (0 < size--) {
 215                ch = *data++;
 216                if (ch == '\n') {
 217                        count++;
 218                        nl_just_seen = 1;
 219                        completely_empty = 0;
 220                }
 221                else {
 222                        nl_just_seen = 0;
 223                        completely_empty = 0;
 224                }
 225        }
 226        if (completely_empty)
 227                return 0;
 228        if (!nl_just_seen)
 229                count++; /* no trailing newline */
 230        return count;
 231}
 232
 233static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 234{
 235        if (!DIFF_FILE_VALID(one)) {
 236                mf->ptr = (char *)""; /* does not matter */
 237                mf->size = 0;
 238                return 0;
 239        }
 240        else if (diff_populate_filespec(one, 0))
 241                return -1;
 242
 243        mf->ptr = one->data;
 244        mf->size = one->size;
 245        return 0;
 246}
 247
 248/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 249static unsigned long diff_filespec_size(struct diff_filespec *one)
 250{
 251        if (!DIFF_FILE_VALID(one))
 252                return 0;
 253        diff_populate_filespec(one, 1);
 254        return one->size;
 255}
 256
 257static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 258{
 259        char *ptr = mf->ptr;
 260        long size = mf->size;
 261        int cnt = 0;
 262
 263        if (!size)
 264                return cnt;
 265        ptr += size - 1; /* pointing at the very end */
 266        if (*ptr != '\n')
 267                ; /* incomplete line */
 268        else
 269                ptr--; /* skip the last LF */
 270        while (mf->ptr < ptr) {
 271                char *prev_eol;
 272                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 273                        if (*prev_eol == '\n')
 274                                break;
 275                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 276                        break;
 277                cnt++;
 278                ptr = prev_eol - 1;
 279        }
 280        return cnt;
 281}
 282
 283static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 284                               struct emit_callback *ecbdata)
 285{
 286        int l1, l2, at;
 287        unsigned ws_rule = ecbdata->ws_rule;
 288        l1 = count_trailing_blank(mf1, ws_rule);
 289        l2 = count_trailing_blank(mf2, ws_rule);
 290        if (l2 <= l1) {
 291                ecbdata->blank_at_eof_in_preimage = 0;
 292                ecbdata->blank_at_eof_in_postimage = 0;
 293                return;
 294        }
 295        at = count_lines(mf1->ptr, mf1->size);
 296        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 297
 298        at = count_lines(mf2->ptr, mf2->size);
 299        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 300}
 301
 302static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 303                        int first, const char *line, int len)
 304{
 305        int has_trailing_newline, has_trailing_carriage_return;
 306        int nofirst;
 307        FILE *file = o->file;
 308
 309        if (o->output_prefix) {
 310                struct strbuf *msg = NULL;
 311                msg = o->output_prefix(o, o->output_prefix_data);
 312                assert(msg);
 313                fwrite(msg->buf, msg->len, 1, file);
 314        }
 315
 316        if (len == 0) {
 317                has_trailing_newline = (first == '\n');
 318                has_trailing_carriage_return = (!has_trailing_newline &&
 319                                                (first == '\r'));
 320                nofirst = has_trailing_newline || has_trailing_carriage_return;
 321        } else {
 322                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 323                if (has_trailing_newline)
 324                        len--;
 325                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 326                if (has_trailing_carriage_return)
 327                        len--;
 328                nofirst = 0;
 329        }
 330
 331        if (len || !nofirst) {
 332                fputs(set, file);
 333                if (!nofirst)
 334                        fputc(first, file);
 335                fwrite(line, len, 1, file);
 336                fputs(reset, file);
 337        }
 338        if (has_trailing_carriage_return)
 339                fputc('\r', file);
 340        if (has_trailing_newline)
 341                fputc('\n', file);
 342}
 343
 344static void emit_line(struct diff_options *o, const char *set, const char *reset,
 345                      const char *line, int len)
 346{
 347        emit_line_0(o, set, reset, line[0], line+1, len-1);
 348}
 349
 350static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 351{
 352        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 353              ecbdata->blank_at_eof_in_preimage &&
 354              ecbdata->blank_at_eof_in_postimage &&
 355              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 356              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 357                return 0;
 358        return ws_blank_line(line, len, ecbdata->ws_rule);
 359}
 360
 361static void emit_add_line(const char *reset,
 362                          struct emit_callback *ecbdata,
 363                          const char *line, int len)
 364{
 365        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 366        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 367
 368        if (!*ws)
 369                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 370        else if (new_blank_line_at_eof(ecbdata, line, len))
 371                /* Blank line at EOF - paint '+' as well */
 372                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 373        else {
 374                /* Emit just the prefix, then the rest. */
 375                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 376                ws_check_emit(line, len, ecbdata->ws_rule,
 377                              ecbdata->opt->file, set, reset, ws);
 378        }
 379}
 380
 381static void emit_hunk_header(struct emit_callback *ecbdata,
 382                             const char *line, int len)
 383{
 384        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 385        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 386        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 387        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 388        static const char atat[2] = { '@', '@' };
 389        const char *cp, *ep;
 390        struct strbuf msgbuf = STRBUF_INIT;
 391        int org_len = len;
 392        int i = 1;
 393
 394        /*
 395         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 396         * it always is at least 10 bytes long.
 397         */
 398        if (len < 10 ||
 399            memcmp(line, atat, 2) ||
 400            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 401                emit_line(ecbdata->opt, plain, reset, line, len);
 402                return;
 403        }
 404        ep += 2; /* skip over @@ */
 405
 406        /* The hunk header in fraginfo color */
 407        strbuf_add(&msgbuf, frag, strlen(frag));
 408        strbuf_add(&msgbuf, line, ep - line);
 409        strbuf_add(&msgbuf, reset, strlen(reset));
 410
 411        /*
 412         * trailing "\r\n"
 413         */
 414        for ( ; i < 3; i++)
 415                if (line[len - i] == '\r' || line[len - i] == '\n')
 416                        len--;
 417
 418        /* blank before the func header */
 419        for (cp = ep; ep - line < len; ep++)
 420                if (*ep != ' ' && *ep != '\t')
 421                        break;
 422        if (ep != cp) {
 423                strbuf_add(&msgbuf, plain, strlen(plain));
 424                strbuf_add(&msgbuf, cp, ep - cp);
 425                strbuf_add(&msgbuf, reset, strlen(reset));
 426        }
 427
 428        if (ep < line + len) {
 429                strbuf_add(&msgbuf, func, strlen(func));
 430                strbuf_add(&msgbuf, ep, line + len - ep);
 431                strbuf_add(&msgbuf, reset, strlen(reset));
 432        }
 433
 434        strbuf_add(&msgbuf, line + len, org_len - len);
 435        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 436        strbuf_release(&msgbuf);
 437}
 438
 439static struct diff_tempfile *claim_diff_tempfile(void) {
 440        int i;
 441        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 442                if (!diff_temp[i].name)
 443                        return diff_temp + i;
 444        die("BUG: diff is failing to clean up its tempfiles");
 445}
 446
 447static int remove_tempfile_installed;
 448
 449static void remove_tempfile(void)
 450{
 451        int i;
 452        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 453                if (diff_temp[i].name == diff_temp[i].tmp_path)
 454                        unlink_or_warn(diff_temp[i].name);
 455                diff_temp[i].name = NULL;
 456        }
 457}
 458
 459static void remove_tempfile_on_signal(int signo)
 460{
 461        remove_tempfile();
 462        sigchain_pop(signo);
 463        raise(signo);
 464}
 465
 466static void print_line_count(FILE *file, int count)
 467{
 468        switch (count) {
 469        case 0:
 470                fprintf(file, "0,0");
 471                break;
 472        case 1:
 473                fprintf(file, "1");
 474                break;
 475        default:
 476                fprintf(file, "1,%d", count);
 477                break;
 478        }
 479}
 480
 481static void emit_rewrite_lines(struct emit_callback *ecb,
 482                               int prefix, const char *data, int size)
 483{
 484        const char *endp = NULL;
 485        static const char *nneof = " No newline at end of file\n";
 486        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 487        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 488
 489        while (0 < size) {
 490                int len;
 491
 492                endp = memchr(data, '\n', size);
 493                len = endp ? (endp - data + 1) : size;
 494                if (prefix != '+') {
 495                        ecb->lno_in_preimage++;
 496                        emit_line_0(ecb->opt, old, reset, '-',
 497                                    data, len);
 498                } else {
 499                        ecb->lno_in_postimage++;
 500                        emit_add_line(reset, ecb, data, len);
 501                }
 502                size -= len;
 503                data += len;
 504        }
 505        if (!endp) {
 506                const char *plain = diff_get_color(ecb->color_diff,
 507                                                   DIFF_PLAIN);
 508                emit_line_0(ecb->opt, plain, reset, '\\',
 509                            nneof, strlen(nneof));
 510        }
 511}
 512
 513static void emit_rewrite_diff(const char *name_a,
 514                              const char *name_b,
 515                              struct diff_filespec *one,
 516                              struct diff_filespec *two,
 517                              struct userdiff_driver *textconv_one,
 518                              struct userdiff_driver *textconv_two,
 519                              struct diff_options *o)
 520{
 521        int lc_a, lc_b;
 522        int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 523        const char *name_a_tab, *name_b_tab;
 524        const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 525        const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 526        const char *reset = diff_get_color(color_diff, DIFF_RESET);
 527        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 528        const char *a_prefix, *b_prefix;
 529        char *data_one, *data_two;
 530        size_t size_one, size_two;
 531        struct emit_callback ecbdata;
 532        char *line_prefix = "";
 533        struct strbuf *msgbuf;
 534
 535        if (o && o->output_prefix) {
 536                msgbuf = o->output_prefix(o, o->output_prefix_data);
 537                line_prefix = msgbuf->buf;
 538        }
 539
 540        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 541                a_prefix = o->b_prefix;
 542                b_prefix = o->a_prefix;
 543        } else {
 544                a_prefix = o->a_prefix;
 545                b_prefix = o->b_prefix;
 546        }
 547
 548        name_a += (*name_a == '/');
 549        name_b += (*name_b == '/');
 550        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 551        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 552
 553        strbuf_reset(&a_name);
 554        strbuf_reset(&b_name);
 555        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 556        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 557
 558        size_one = fill_textconv(textconv_one, one, &data_one);
 559        size_two = fill_textconv(textconv_two, two, &data_two);
 560
 561        memset(&ecbdata, 0, sizeof(ecbdata));
 562        ecbdata.color_diff = color_diff;
 563        ecbdata.found_changesp = &o->found_changes;
 564        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 565        ecbdata.opt = o;
 566        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 567                mmfile_t mf1, mf2;
 568                mf1.ptr = (char *)data_one;
 569                mf2.ptr = (char *)data_two;
 570                mf1.size = size_one;
 571                mf2.size = size_two;
 572                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 573        }
 574        ecbdata.lno_in_preimage = 1;
 575        ecbdata.lno_in_postimage = 1;
 576
 577        lc_a = count_lines(data_one, size_one);
 578        lc_b = count_lines(data_two, size_two);
 579        fprintf(o->file,
 580                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 581                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 582                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 583                line_prefix, fraginfo);
 584        if (!o->irreversible_delete)
 585                print_line_count(o->file, lc_a);
 586        else
 587                fprintf(o->file, "?,?");
 588        fprintf(o->file, " +");
 589        print_line_count(o->file, lc_b);
 590        fprintf(o->file, " @@%s\n", reset);
 591        if (lc_a && !o->irreversible_delete)
 592                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 593        if (lc_b)
 594                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 595        if (textconv_one)
 596                free((char *)data_one);
 597        if (textconv_two)
 598                free((char *)data_two);
 599}
 600
 601struct diff_words_buffer {
 602        mmfile_t text;
 603        long alloc;
 604        struct diff_words_orig {
 605                const char *begin, *end;
 606        } *orig;
 607        int orig_nr, orig_alloc;
 608};
 609
 610static void diff_words_append(char *line, unsigned long len,
 611                struct diff_words_buffer *buffer)
 612{
 613        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 614        line++;
 615        len--;
 616        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 617        buffer->text.size += len;
 618        buffer->text.ptr[buffer->text.size] = '\0';
 619}
 620
 621struct diff_words_style_elem {
 622        const char *prefix;
 623        const char *suffix;
 624        const char *color; /* NULL; filled in by the setup code if
 625                            * color is enabled */
 626};
 627
 628struct diff_words_style {
 629        enum diff_words_type type;
 630        struct diff_words_style_elem new, old, ctx;
 631        const char *newline;
 632};
 633
 634static struct diff_words_style diff_words_styles[] = {
 635        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 636        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 637        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 638};
 639
 640struct diff_words_data {
 641        struct diff_words_buffer minus, plus;
 642        const char *current_plus;
 643        int last_minus;
 644        struct diff_options *opt;
 645        regex_t *word_regex;
 646        enum diff_words_type type;
 647        struct diff_words_style *style;
 648};
 649
 650static int fn_out_diff_words_write_helper(FILE *fp,
 651                                          struct diff_words_style_elem *st_el,
 652                                          const char *newline,
 653                                          size_t count, const char *buf,
 654                                          const char *line_prefix)
 655{
 656        int print = 0;
 657
 658        while (count) {
 659                char *p = memchr(buf, '\n', count);
 660                if (print)
 661                        fputs(line_prefix, fp);
 662                if (p != buf) {
 663                        if (st_el->color && fputs(st_el->color, fp) < 0)
 664                                return -1;
 665                        if (fputs(st_el->prefix, fp) < 0 ||
 666                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 667                            fputs(st_el->suffix, fp) < 0)
 668                                return -1;
 669                        if (st_el->color && *st_el->color
 670                            && fputs(GIT_COLOR_RESET, fp) < 0)
 671                                return -1;
 672                }
 673                if (!p)
 674                        return 0;
 675                if (fputs(newline, fp) < 0)
 676                        return -1;
 677                count -= p + 1 - buf;
 678                buf = p + 1;
 679                print = 1;
 680        }
 681        return 0;
 682}
 683
 684/*
 685 * '--color-words' algorithm can be described as:
 686 *
 687 *   1. collect a the minus/plus lines of a diff hunk, divided into
 688 *      minus-lines and plus-lines;
 689 *
 690 *   2. break both minus-lines and plus-lines into words and
 691 *      place them into two mmfile_t with one word for each line;
 692 *
 693 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 694 *
 695 * And for the common parts of the both file, we output the plus side text.
 696 * diff_words->current_plus is used to trace the current position of the plus file
 697 * which printed. diff_words->last_minus is used to trace the last minus word
 698 * printed.
 699 *
 700 * For '--graph' to work with '--color-words', we need to output the graph prefix
 701 * on each line of color words output. Generally, there are two conditions on
 702 * which we should output the prefix.
 703 *
 704 *   1. diff_words->last_minus == 0 &&
 705 *      diff_words->current_plus == diff_words->plus.text.ptr
 706 *
 707 *      that is: the plus text must start as a new line, and if there is no minus
 708 *      word printed, a graph prefix must be printed.
 709 *
 710 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 711 *      *(diff_words->current_plus - 1) == '\n'
 712 *
 713 *      that is: a graph prefix must be printed following a '\n'
 714 */
 715static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 716{
 717        if ((diff_words->last_minus == 0 &&
 718                diff_words->current_plus == diff_words->plus.text.ptr) ||
 719                (diff_words->current_plus > diff_words->plus.text.ptr &&
 720                *(diff_words->current_plus - 1) == '\n')) {
 721                return 1;
 722        } else {
 723                return 0;
 724        }
 725}
 726
 727static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 728{
 729        struct diff_words_data *diff_words = priv;
 730        struct diff_words_style *style = diff_words->style;
 731        int minus_first, minus_len, plus_first, plus_len;
 732        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 733        struct diff_options *opt = diff_words->opt;
 734        struct strbuf *msgbuf;
 735        char *line_prefix = "";
 736
 737        if (line[0] != '@' || parse_hunk_header(line, len,
 738                        &minus_first, &minus_len, &plus_first, &plus_len))
 739                return;
 740
 741        assert(opt);
 742        if (opt->output_prefix) {
 743                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 744                line_prefix = msgbuf->buf;
 745        }
 746
 747        /* POSIX requires that first be decremented by one if len == 0... */
 748        if (minus_len) {
 749                minus_begin = diff_words->minus.orig[minus_first].begin;
 750                minus_end =
 751                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 752        } else
 753                minus_begin = minus_end =
 754                        diff_words->minus.orig[minus_first].end;
 755
 756        if (plus_len) {
 757                plus_begin = diff_words->plus.orig[plus_first].begin;
 758                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 759        } else
 760                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 761
 762        if (color_words_output_graph_prefix(diff_words)) {
 763                fputs(line_prefix, diff_words->opt->file);
 764        }
 765        if (diff_words->current_plus != plus_begin) {
 766                fn_out_diff_words_write_helper(diff_words->opt->file,
 767                                &style->ctx, style->newline,
 768                                plus_begin - diff_words->current_plus,
 769                                diff_words->current_plus, line_prefix);
 770                if (*(plus_begin - 1) == '\n')
 771                        fputs(line_prefix, diff_words->opt->file);
 772        }
 773        if (minus_begin != minus_end) {
 774                fn_out_diff_words_write_helper(diff_words->opt->file,
 775                                &style->old, style->newline,
 776                                minus_end - minus_begin, minus_begin,
 777                                line_prefix);
 778        }
 779        if (plus_begin != plus_end) {
 780                fn_out_diff_words_write_helper(diff_words->opt->file,
 781                                &style->new, style->newline,
 782                                plus_end - plus_begin, plus_begin,
 783                                line_prefix);
 784        }
 785
 786        diff_words->current_plus = plus_end;
 787        diff_words->last_minus = minus_first;
 788}
 789
 790/* This function starts looking at *begin, and returns 0 iff a word was found. */
 791static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 792                int *begin, int *end)
 793{
 794        if (word_regex && *begin < buffer->size) {
 795                regmatch_t match[1];
 796                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 797                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 798                                        '\n', match[0].rm_eo - match[0].rm_so);
 799                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 800                        *begin += match[0].rm_so;
 801                        return *begin >= *end;
 802                }
 803                return -1;
 804        }
 805
 806        /* find the next word */
 807        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 808                (*begin)++;
 809        if (*begin >= buffer->size)
 810                return -1;
 811
 812        /* find the end of the word */
 813        *end = *begin + 1;
 814        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 815                (*end)++;
 816
 817        return 0;
 818}
 819
 820/*
 821 * This function splits the words in buffer->text, stores the list with
 822 * newline separator into out, and saves the offsets of the original words
 823 * in buffer->orig.
 824 */
 825static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 826                regex_t *word_regex)
 827{
 828        int i, j;
 829        long alloc = 0;
 830
 831        out->size = 0;
 832        out->ptr = NULL;
 833
 834        /* fake an empty "0th" word */
 835        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 836        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 837        buffer->orig_nr = 1;
 838
 839        for (i = 0; i < buffer->text.size; i++) {
 840                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 841                        return;
 842
 843                /* store original boundaries */
 844                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 845                                buffer->orig_alloc);
 846                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 847                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 848                buffer->orig_nr++;
 849
 850                /* store one word */
 851                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 852                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 853                out->ptr[out->size + j - i] = '\n';
 854                out->size += j - i + 1;
 855
 856                i = j - 1;
 857        }
 858}
 859
 860/* this executes the word diff on the accumulated buffers */
 861static void diff_words_show(struct diff_words_data *diff_words)
 862{
 863        xpparam_t xpp;
 864        xdemitconf_t xecfg;
 865        mmfile_t minus, plus;
 866        struct diff_words_style *style = diff_words->style;
 867
 868        struct diff_options *opt = diff_words->opt;
 869        struct strbuf *msgbuf;
 870        char *line_prefix = "";
 871
 872        assert(opt);
 873        if (opt->output_prefix) {
 874                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 875                line_prefix = msgbuf->buf;
 876        }
 877
 878        /* special case: only removal */
 879        if (!diff_words->plus.text.size) {
 880                fputs(line_prefix, diff_words->opt->file);
 881                fn_out_diff_words_write_helper(diff_words->opt->file,
 882                        &style->old, style->newline,
 883                        diff_words->minus.text.size,
 884                        diff_words->minus.text.ptr, line_prefix);
 885                diff_words->minus.text.size = 0;
 886                return;
 887        }
 888
 889        diff_words->current_plus = diff_words->plus.text.ptr;
 890        diff_words->last_minus = 0;
 891
 892        memset(&xpp, 0, sizeof(xpp));
 893        memset(&xecfg, 0, sizeof(xecfg));
 894        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 895        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 896        xpp.flags = 0;
 897        /* as only the hunk header will be parsed, we need a 0-context */
 898        xecfg.ctxlen = 0;
 899        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 900                      &xpp, &xecfg);
 901        free(minus.ptr);
 902        free(plus.ptr);
 903        if (diff_words->current_plus != diff_words->plus.text.ptr +
 904                        diff_words->plus.text.size) {
 905                if (color_words_output_graph_prefix(diff_words))
 906                        fputs(line_prefix, diff_words->opt->file);
 907                fn_out_diff_words_write_helper(diff_words->opt->file,
 908                        &style->ctx, style->newline,
 909                        diff_words->plus.text.ptr + diff_words->plus.text.size
 910                        - diff_words->current_plus, diff_words->current_plus,
 911                        line_prefix);
 912        }
 913        diff_words->minus.text.size = diff_words->plus.text.size = 0;
 914}
 915
 916/* In "color-words" mode, show word-diff of words accumulated in the buffer */
 917static void diff_words_flush(struct emit_callback *ecbdata)
 918{
 919        if (ecbdata->diff_words->minus.text.size ||
 920            ecbdata->diff_words->plus.text.size)
 921                diff_words_show(ecbdata->diff_words);
 922}
 923
 924static void free_diff_words_data(struct emit_callback *ecbdata)
 925{
 926        if (ecbdata->diff_words) {
 927                diff_words_flush(ecbdata);
 928                free (ecbdata->diff_words->minus.text.ptr);
 929                free (ecbdata->diff_words->minus.orig);
 930                free (ecbdata->diff_words->plus.text.ptr);
 931                free (ecbdata->diff_words->plus.orig);
 932                if (ecbdata->diff_words->word_regex) {
 933                        regfree(ecbdata->diff_words->word_regex);
 934                        free(ecbdata->diff_words->word_regex);
 935                }
 936                free(ecbdata->diff_words);
 937                ecbdata->diff_words = NULL;
 938        }
 939}
 940
 941const char *diff_get_color(int diff_use_color, enum color_diff ix)
 942{
 943        if (diff_use_color)
 944                return diff_colors[ix];
 945        return "";
 946}
 947
 948static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 949{
 950        const char *cp;
 951        unsigned long allot;
 952        size_t l = len;
 953
 954        if (ecb->truncate)
 955                return ecb->truncate(line, len);
 956        cp = line;
 957        allot = l;
 958        while (0 < l) {
 959                (void) utf8_width(&cp, &l);
 960                if (!cp)
 961                        break; /* truncated in the middle? */
 962        }
 963        return allot - l;
 964}
 965
 966static void find_lno(const char *line, struct emit_callback *ecbdata)
 967{
 968        const char *p;
 969        ecbdata->lno_in_preimage = 0;
 970        ecbdata->lno_in_postimage = 0;
 971        p = strchr(line, '-');
 972        if (!p)
 973                return; /* cannot happen */
 974        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
 975        p = strchr(p, '+');
 976        if (!p)
 977                return; /* cannot happen */
 978        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
 979}
 980
 981static void fn_out_consume(void *priv, char *line, unsigned long len)
 982{
 983        struct emit_callback *ecbdata = priv;
 984        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 985        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 986        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 987        struct diff_options *o = ecbdata->opt;
 988        char *line_prefix = "";
 989        struct strbuf *msgbuf;
 990
 991        if (o && o->output_prefix) {
 992                msgbuf = o->output_prefix(o, o->output_prefix_data);
 993                line_prefix = msgbuf->buf;
 994        }
 995
 996        if (ecbdata->header) {
 997                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
 998                strbuf_reset(ecbdata->header);
 999                ecbdata->header = NULL;
1000        }
1001        *(ecbdata->found_changesp) = 1;
1002
1003        if (ecbdata->label_path[0]) {
1004                const char *name_a_tab, *name_b_tab;
1005
1006                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1007                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1008
1009                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1010                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1011                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1012                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1013                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1014        }
1015
1016        if (diff_suppress_blank_empty
1017            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1018                line[0] = '\n';
1019                len = 1;
1020        }
1021
1022        if (line[0] == '@') {
1023                if (ecbdata->diff_words)
1024                        diff_words_flush(ecbdata);
1025                len = sane_truncate_line(ecbdata, line, len);
1026                find_lno(line, ecbdata);
1027                emit_hunk_header(ecbdata, line, len);
1028                if (line[len-1] != '\n')
1029                        putc('\n', ecbdata->opt->file);
1030                return;
1031        }
1032
1033        if (len < 1) {
1034                emit_line(ecbdata->opt, reset, reset, line, len);
1035                if (ecbdata->diff_words
1036                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1037                        fputs("~\n", ecbdata->opt->file);
1038                return;
1039        }
1040
1041        if (ecbdata->diff_words) {
1042                if (line[0] == '-') {
1043                        diff_words_append(line, len,
1044                                          &ecbdata->diff_words->minus);
1045                        return;
1046                } else if (line[0] == '+') {
1047                        diff_words_append(line, len,
1048                                          &ecbdata->diff_words->plus);
1049                        return;
1050                }
1051                diff_words_flush(ecbdata);
1052                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1053                        emit_line(ecbdata->opt, plain, reset, line, len);
1054                        fputs("~\n", ecbdata->opt->file);
1055                } else {
1056                        /* don't print the prefix character */
1057                        emit_line(ecbdata->opt, plain, reset, line+1, len-1);
1058                }
1059                return;
1060        }
1061
1062        if (line[0] != '+') {
1063                const char *color =
1064                        diff_get_color(ecbdata->color_diff,
1065                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1066                ecbdata->lno_in_preimage++;
1067                if (line[0] == ' ')
1068                        ecbdata->lno_in_postimage++;
1069                emit_line(ecbdata->opt, color, reset, line, len);
1070        } else {
1071                ecbdata->lno_in_postimage++;
1072                emit_add_line(reset, ecbdata, line + 1, len - 1);
1073        }
1074}
1075
1076static char *pprint_rename(const char *a, const char *b)
1077{
1078        const char *old = a;
1079        const char *new = b;
1080        struct strbuf name = STRBUF_INIT;
1081        int pfx_length, sfx_length;
1082        int len_a = strlen(a);
1083        int len_b = strlen(b);
1084        int a_midlen, b_midlen;
1085        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1086        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1087
1088        if (qlen_a || qlen_b) {
1089                quote_c_style(a, &name, NULL, 0);
1090                strbuf_addstr(&name, " => ");
1091                quote_c_style(b, &name, NULL, 0);
1092                return strbuf_detach(&name, NULL);
1093        }
1094
1095        /* Find common prefix */
1096        pfx_length = 0;
1097        while (*old && *new && *old == *new) {
1098                if (*old == '/')
1099                        pfx_length = old - a + 1;
1100                old++;
1101                new++;
1102        }
1103
1104        /* Find common suffix */
1105        old = a + len_a;
1106        new = b + len_b;
1107        sfx_length = 0;
1108        while (a <= old && b <= new && *old == *new) {
1109                if (*old == '/')
1110                        sfx_length = len_a - (old - a);
1111                old--;
1112                new--;
1113        }
1114
1115        /*
1116         * pfx{mid-a => mid-b}sfx
1117         * {pfx-a => pfx-b}sfx
1118         * pfx{sfx-a => sfx-b}
1119         * name-a => name-b
1120         */
1121        a_midlen = len_a - pfx_length - sfx_length;
1122        b_midlen = len_b - pfx_length - sfx_length;
1123        if (a_midlen < 0)
1124                a_midlen = 0;
1125        if (b_midlen < 0)
1126                b_midlen = 0;
1127
1128        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1129        if (pfx_length + sfx_length) {
1130                strbuf_add(&name, a, pfx_length);
1131                strbuf_addch(&name, '{');
1132        }
1133        strbuf_add(&name, a + pfx_length, a_midlen);
1134        strbuf_addstr(&name, " => ");
1135        strbuf_add(&name, b + pfx_length, b_midlen);
1136        if (pfx_length + sfx_length) {
1137                strbuf_addch(&name, '}');
1138                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1139        }
1140        return strbuf_detach(&name, NULL);
1141}
1142
1143struct diffstat_t {
1144        int nr;
1145        int alloc;
1146        struct diffstat_file {
1147                char *from_name;
1148                char *name;
1149                char *print_name;
1150                unsigned is_unmerged:1;
1151                unsigned is_binary:1;
1152                unsigned is_renamed:1;
1153                uintmax_t added, deleted;
1154        } **files;
1155};
1156
1157static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1158                                          const char *name_a,
1159                                          const char *name_b)
1160{
1161        struct diffstat_file *x;
1162        x = xcalloc(sizeof (*x), 1);
1163        if (diffstat->nr == diffstat->alloc) {
1164                diffstat->alloc = alloc_nr(diffstat->alloc);
1165                diffstat->files = xrealloc(diffstat->files,
1166                                diffstat->alloc * sizeof(x));
1167        }
1168        diffstat->files[diffstat->nr++] = x;
1169        if (name_b) {
1170                x->from_name = xstrdup(name_a);
1171                x->name = xstrdup(name_b);
1172                x->is_renamed = 1;
1173        }
1174        else {
1175                x->from_name = NULL;
1176                x->name = xstrdup(name_a);
1177        }
1178        return x;
1179}
1180
1181static void diffstat_consume(void *priv, char *line, unsigned long len)
1182{
1183        struct diffstat_t *diffstat = priv;
1184        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1185
1186        if (line[0] == '+')
1187                x->added++;
1188        else if (line[0] == '-')
1189                x->deleted++;
1190}
1191
1192const char mime_boundary_leader[] = "------------";
1193
1194static int scale_linear(int it, int width, int max_change)
1195{
1196        /*
1197         * make sure that at least one '-' is printed if there were deletions,
1198         * and likewise for '+'.
1199         */
1200        if (max_change < 2)
1201                return it;
1202        return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
1203}
1204
1205static void show_name(FILE *file,
1206                      const char *prefix, const char *name, int len)
1207{
1208        fprintf(file, " %s%-*s |", prefix, len, name);
1209}
1210
1211static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1212{
1213        if (cnt <= 0)
1214                return;
1215        fprintf(file, "%s", set);
1216        while (cnt--)
1217                putc(ch, file);
1218        fprintf(file, "%s", reset);
1219}
1220
1221static void fill_print_name(struct diffstat_file *file)
1222{
1223        char *pname;
1224
1225        if (file->print_name)
1226                return;
1227
1228        if (!file->is_renamed) {
1229                struct strbuf buf = STRBUF_INIT;
1230                if (quote_c_style(file->name, &buf, NULL, 0)) {
1231                        pname = strbuf_detach(&buf, NULL);
1232                } else {
1233                        pname = file->name;
1234                        strbuf_release(&buf);
1235                }
1236        } else {
1237                pname = pprint_rename(file->from_name, file->name);
1238        }
1239        file->print_name = pname;
1240}
1241
1242static void show_stats(struct diffstat_t *data, struct diff_options *options)
1243{
1244        int i, len, add, del, adds = 0, dels = 0;
1245        uintmax_t max_change = 0, max_len = 0;
1246        int total_files = data->nr;
1247        int width, name_width;
1248        const char *reset, *add_c, *del_c;
1249        const char *line_prefix = "";
1250        struct strbuf *msg = NULL;
1251
1252        if (data->nr == 0)
1253                return;
1254
1255        if (options->output_prefix) {
1256                msg = options->output_prefix(options, options->output_prefix_data);
1257                line_prefix = msg->buf;
1258        }
1259
1260        width = options->stat_width ? options->stat_width : 80;
1261        name_width = options->stat_name_width ? options->stat_name_width : 50;
1262
1263        /* Sanity: give at least 5 columns to the graph,
1264         * but leave at least 10 columns for the name.
1265         */
1266        if (width < 25)
1267                width = 25;
1268        if (name_width < 10)
1269                name_width = 10;
1270        else if (width < name_width + 15)
1271                name_width = width - 15;
1272
1273        /* Find the longest filename and max number of changes */
1274        reset = diff_get_color_opt(options, DIFF_RESET);
1275        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1276        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1277
1278        for (i = 0; i < data->nr; i++) {
1279                struct diffstat_file *file = data->files[i];
1280                uintmax_t change = file->added + file->deleted;
1281                if (!data->files[i]->is_renamed &&
1282                         (change == 0)) {
1283                        continue;
1284                }
1285                fill_print_name(file);
1286                len = strlen(file->print_name);
1287                if (max_len < len)
1288                        max_len = len;
1289
1290                if (file->is_binary || file->is_unmerged)
1291                        continue;
1292                if (max_change < change)
1293                        max_change = change;
1294        }
1295
1296        /* Compute the width of the graph part;
1297         * 10 is for one blank at the beginning of the line plus
1298         * " | count " between the name and the graph.
1299         *
1300         * From here on, name_width is the width of the name area,
1301         * and width is the width of the graph area.
1302         */
1303        name_width = (name_width < max_len) ? name_width : max_len;
1304        if (width < (name_width + 10) + max_change)
1305                width = width - (name_width + 10);
1306        else
1307                width = max_change;
1308
1309        for (i = 0; i < data->nr; i++) {
1310                const char *prefix = "";
1311                char *name = data->files[i]->print_name;
1312                uintmax_t added = data->files[i]->added;
1313                uintmax_t deleted = data->files[i]->deleted;
1314                int name_len;
1315
1316                if (!data->files[i]->is_renamed &&
1317                         (added + deleted == 0)) {
1318                        total_files--;
1319                        continue;
1320                }
1321                /*
1322                 * "scale" the filename
1323                 */
1324                len = name_width;
1325                name_len = strlen(name);
1326                if (name_width < name_len) {
1327                        char *slash;
1328                        prefix = "...";
1329                        len -= 3;
1330                        name += name_len - len;
1331                        slash = strchr(name, '/');
1332                        if (slash)
1333                                name = slash;
1334                }
1335
1336                if (data->files[i]->is_binary) {
1337                        fprintf(options->file, "%s", line_prefix);
1338                        show_name(options->file, prefix, name, len);
1339                        fprintf(options->file, "  Bin ");
1340                        fprintf(options->file, "%s%"PRIuMAX"%s",
1341                                del_c, deleted, reset);
1342                        fprintf(options->file, " -> ");
1343                        fprintf(options->file, "%s%"PRIuMAX"%s",
1344                                add_c, added, reset);
1345                        fprintf(options->file, " bytes");
1346                        fprintf(options->file, "\n");
1347                        continue;
1348                }
1349                else if (data->files[i]->is_unmerged) {
1350                        fprintf(options->file, "%s", line_prefix);
1351                        show_name(options->file, prefix, name, len);
1352                        fprintf(options->file, "  Unmerged\n");
1353                        continue;
1354                }
1355
1356                /*
1357                 * scale the add/delete
1358                 */
1359                add = added;
1360                del = deleted;
1361                adds += add;
1362                dels += del;
1363
1364                if (width <= max_change) {
1365                        add = scale_linear(add, width, max_change);
1366                        del = scale_linear(del, width, max_change);
1367                }
1368                fprintf(options->file, "%s", line_prefix);
1369                show_name(options->file, prefix, name, len);
1370                fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
1371                                added + deleted ? " " : "");
1372                show_graph(options->file, '+', add, add_c, reset);
1373                show_graph(options->file, '-', del, del_c, reset);
1374                fprintf(options->file, "\n");
1375        }
1376        fprintf(options->file, "%s", line_prefix);
1377        fprintf(options->file,
1378               " %d files changed, %d insertions(+), %d deletions(-)\n",
1379               total_files, adds, dels);
1380}
1381
1382static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1383{
1384        int i, adds = 0, dels = 0, total_files = data->nr;
1385
1386        if (data->nr == 0)
1387                return;
1388
1389        for (i = 0; i < data->nr; i++) {
1390                if (!data->files[i]->is_binary &&
1391                    !data->files[i]->is_unmerged) {
1392                        int added = data->files[i]->added;
1393                        int deleted= data->files[i]->deleted;
1394                        if (!data->files[i]->is_renamed &&
1395                            (added + deleted == 0)) {
1396                                total_files--;
1397                        } else {
1398                                adds += added;
1399                                dels += deleted;
1400                        }
1401                }
1402        }
1403        if (options->output_prefix) {
1404                struct strbuf *msg = NULL;
1405                msg = options->output_prefix(options,
1406                                options->output_prefix_data);
1407                fprintf(options->file, "%s", msg->buf);
1408        }
1409        fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
1410               total_files, adds, dels);
1411}
1412
1413static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1414{
1415        int i;
1416
1417        if (data->nr == 0)
1418                return;
1419
1420        for (i = 0; i < data->nr; i++) {
1421                struct diffstat_file *file = data->files[i];
1422
1423                if (options->output_prefix) {
1424                        struct strbuf *msg = NULL;
1425                        msg = options->output_prefix(options,
1426                                        options->output_prefix_data);
1427                        fprintf(options->file, "%s", msg->buf);
1428                }
1429
1430                if (file->is_binary)
1431                        fprintf(options->file, "-\t-\t");
1432                else
1433                        fprintf(options->file,
1434                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1435                                file->added, file->deleted);
1436                if (options->line_termination) {
1437                        fill_print_name(file);
1438                        if (!file->is_renamed)
1439                                write_name_quoted(file->name, options->file,
1440                                                  options->line_termination);
1441                        else {
1442                                fputs(file->print_name, options->file);
1443                                putc(options->line_termination, options->file);
1444                        }
1445                } else {
1446                        if (file->is_renamed) {
1447                                putc('\0', options->file);
1448                                write_name_quoted(file->from_name, options->file, '\0');
1449                        }
1450                        write_name_quoted(file->name, options->file, '\0');
1451                }
1452        }
1453}
1454
1455struct dirstat_file {
1456        const char *name;
1457        unsigned long changed;
1458};
1459
1460struct dirstat_dir {
1461        struct dirstat_file *files;
1462        int alloc, nr, percent, cumulative;
1463};
1464
1465static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1466                unsigned long changed, const char *base, int baselen)
1467{
1468        unsigned long this_dir = 0;
1469        unsigned int sources = 0;
1470        const char *line_prefix = "";
1471        struct strbuf *msg = NULL;
1472
1473        if (opt->output_prefix) {
1474                msg = opt->output_prefix(opt, opt->output_prefix_data);
1475                line_prefix = msg->buf;
1476        }
1477
1478        while (dir->nr) {
1479                struct dirstat_file *f = dir->files;
1480                int namelen = strlen(f->name);
1481                unsigned long this;
1482                char *slash;
1483
1484                if (namelen < baselen)
1485                        break;
1486                if (memcmp(f->name, base, baselen))
1487                        break;
1488                slash = strchr(f->name + baselen, '/');
1489                if (slash) {
1490                        int newbaselen = slash + 1 - f->name;
1491                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1492                        sources++;
1493                } else {
1494                        this = f->changed;
1495                        dir->files++;
1496                        dir->nr--;
1497                        sources += 2;
1498                }
1499                this_dir += this;
1500        }
1501
1502        /*
1503         * We don't report dirstat's for
1504         *  - the top level
1505         *  - or cases where everything came from a single directory
1506         *    under this directory (sources == 1).
1507         */
1508        if (baselen && sources != 1) {
1509                int permille = this_dir * 1000 / changed;
1510                if (permille) {
1511                        int percent = permille / 10;
1512                        if (percent >= dir->percent) {
1513                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1514                                        percent, permille % 10, baselen, base);
1515                                if (!dir->cumulative)
1516                                        return 0;
1517                        }
1518                }
1519        }
1520        return this_dir;
1521}
1522
1523static int dirstat_compare(const void *_a, const void *_b)
1524{
1525        const struct dirstat_file *a = _a;
1526        const struct dirstat_file *b = _b;
1527        return strcmp(a->name, b->name);
1528}
1529
1530static void show_dirstat(struct diff_options *options)
1531{
1532        int i;
1533        unsigned long changed;
1534        struct dirstat_dir dir;
1535        struct diff_queue_struct *q = &diff_queued_diff;
1536
1537        dir.files = NULL;
1538        dir.alloc = 0;
1539        dir.nr = 0;
1540        dir.percent = options->dirstat_percent;
1541        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1542
1543        changed = 0;
1544        for (i = 0; i < q->nr; i++) {
1545                struct diff_filepair *p = q->queue[i];
1546                const char *name;
1547                unsigned long copied, added, damage;
1548                int content_changed;
1549
1550                name = p->two->path ? p->two->path : p->one->path;
1551
1552                if (p->one->sha1_valid && p->two->sha1_valid)
1553                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1554                else
1555                        content_changed = 1;
1556
1557                if (!content_changed) {
1558                        /*
1559                         * The SHA1 has not changed, so pre-/post-content is
1560                         * identical. We can therefore skip looking at the
1561                         * file contents altogether.
1562                         */
1563                        damage = 0;
1564                        goto found_damage;
1565                }
1566
1567                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1568                        /*
1569                         * In --dirstat-by-file mode, we don't really need to
1570                         * look at the actual file contents at all.
1571                         * The fact that the SHA1 changed is enough for us to
1572                         * add this file to the list of results
1573                         * (with each file contributing equal damage).
1574                         */
1575                        damage = 1;
1576                        goto found_damage;
1577                }
1578
1579                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1580                        diff_populate_filespec(p->one, 0);
1581                        diff_populate_filespec(p->two, 0);
1582                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1583                                               &copied, &added);
1584                        diff_free_filespec_data(p->one);
1585                        diff_free_filespec_data(p->two);
1586                } else if (DIFF_FILE_VALID(p->one)) {
1587                        diff_populate_filespec(p->one, 1);
1588                        copied = added = 0;
1589                        diff_free_filespec_data(p->one);
1590                } else if (DIFF_FILE_VALID(p->two)) {
1591                        diff_populate_filespec(p->two, 1);
1592                        copied = 0;
1593                        added = p->two->size;
1594                        diff_free_filespec_data(p->two);
1595                } else
1596                        continue;
1597
1598                /*
1599                 * Original minus copied is the removed material,
1600                 * added is the new material.  They are both damages
1601                 * made to the preimage.
1602                 * If the resulting damage is zero, we know that
1603                 * diffcore_count_changes() considers the two entries to
1604                 * be identical, but since content_changed is true, we
1605                 * know that there must have been _some_ kind of change,
1606                 * so we force all entries to have damage > 0.
1607                 */
1608                damage = (p->one->size - copied) + added;
1609                if (!damage)
1610                        damage = 1;
1611
1612found_damage:
1613                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1614                dir.files[dir.nr].name = name;
1615                dir.files[dir.nr].changed = damage;
1616                changed += damage;
1617                dir.nr++;
1618        }
1619
1620        /* This can happen even with many files, if everything was renames */
1621        if (!changed)
1622                return;
1623
1624        /* Show all directories with more than x% of the changes */
1625        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1626        gather_dirstat(options, &dir, changed, "", 0);
1627}
1628
1629static void free_diffstat_info(struct diffstat_t *diffstat)
1630{
1631        int i;
1632        for (i = 0; i < diffstat->nr; i++) {
1633                struct diffstat_file *f = diffstat->files[i];
1634                if (f->name != f->print_name)
1635                        free(f->print_name);
1636                free(f->name);
1637                free(f->from_name);
1638                free(f);
1639        }
1640        free(diffstat->files);
1641}
1642
1643struct checkdiff_t {
1644        const char *filename;
1645        int lineno;
1646        int conflict_marker_size;
1647        struct diff_options *o;
1648        unsigned ws_rule;
1649        unsigned status;
1650};
1651
1652static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
1653{
1654        char firstchar;
1655        int cnt;
1656
1657        if (len < marker_size + 1)
1658                return 0;
1659        firstchar = line[0];
1660        switch (firstchar) {
1661        case '=': case '>': case '<': case '|':
1662                break;
1663        default:
1664                return 0;
1665        }
1666        for (cnt = 1; cnt < marker_size; cnt++)
1667                if (line[cnt] != firstchar)
1668                        return 0;
1669        /* line[1] thru line[marker_size-1] are same as firstchar */
1670        if (len < marker_size + 1 || !isspace(line[marker_size]))
1671                return 0;
1672        return 1;
1673}
1674
1675static void checkdiff_consume(void *priv, char *line, unsigned long len)
1676{
1677        struct checkdiff_t *data = priv;
1678        int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1679        int marker_size = data->conflict_marker_size;
1680        const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1681        const char *reset = diff_get_color(color_diff, DIFF_RESET);
1682        const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1683        char *err;
1684        char *line_prefix = "";
1685        struct strbuf *msgbuf;
1686
1687        assert(data->o);
1688        if (data->o->output_prefix) {
1689                msgbuf = data->o->output_prefix(data->o,
1690                        data->o->output_prefix_data);
1691                line_prefix = msgbuf->buf;
1692        }
1693
1694        if (line[0] == '+') {
1695                unsigned bad;
1696                data->lineno++;
1697                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
1698                        data->status |= 1;
1699                        fprintf(data->o->file,
1700                                "%s%s:%d: leftover conflict marker\n",
1701                                line_prefix, data->filename, data->lineno);
1702                }
1703                bad = ws_check(line + 1, len - 1, data->ws_rule);
1704                if (!bad)
1705                        return;
1706                data->status |= bad;
1707                err = whitespace_error_string(bad);
1708                fprintf(data->o->file, "%s%s:%d: %s.\n",
1709                        line_prefix, data->filename, data->lineno, err);
1710                free(err);
1711                emit_line(data->o, set, reset, line, 1);
1712                ws_check_emit(line + 1, len - 1, data->ws_rule,
1713                              data->o->file, set, reset, ws);
1714        } else if (line[0] == ' ') {
1715                data->lineno++;
1716        } else if (line[0] == '@') {
1717                char *plus = strchr(line, '+');
1718                if (plus)
1719                        data->lineno = strtol(plus, NULL, 10) - 1;
1720                else
1721                        die("invalid diff");
1722        }
1723}
1724
1725static unsigned char *deflate_it(char *data,
1726                                 unsigned long size,
1727                                 unsigned long *result_size)
1728{
1729        int bound;
1730        unsigned char *deflated;
1731        z_stream stream;
1732
1733        memset(&stream, 0, sizeof(stream));
1734        deflateInit(&stream, zlib_compression_level);
1735        bound = deflateBound(&stream, size);
1736        deflated = xmalloc(bound);
1737        stream.next_out = deflated;
1738        stream.avail_out = bound;
1739
1740        stream.next_in = (unsigned char *)data;
1741        stream.avail_in = size;
1742        while (deflate(&stream, Z_FINISH) == Z_OK)
1743                ; /* nothing */
1744        deflateEnd(&stream);
1745        *result_size = stream.total_out;
1746        return deflated;
1747}
1748
1749static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1750{
1751        void *cp;
1752        void *delta;
1753        void *deflated;
1754        void *data;
1755        unsigned long orig_size;
1756        unsigned long delta_size;
1757        unsigned long deflate_size;
1758        unsigned long data_size;
1759
1760        /* We could do deflated delta, or we could do just deflated two,
1761         * whichever is smaller.
1762         */
1763        delta = NULL;
1764        deflated = deflate_it(two->ptr, two->size, &deflate_size);
1765        if (one->size && two->size) {
1766                delta = diff_delta(one->ptr, one->size,
1767                                   two->ptr, two->size,
1768                                   &delta_size, deflate_size);
1769                if (delta) {
1770                        void *to_free = delta;
1771                        orig_size = delta_size;
1772                        delta = deflate_it(delta, delta_size, &delta_size);
1773                        free(to_free);
1774                }
1775        }
1776
1777        if (delta && delta_size < deflate_size) {
1778                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
1779                free(deflated);
1780                data = delta;
1781                data_size = delta_size;
1782        }
1783        else {
1784                fprintf(file, "%sliteral %lu\n", prefix, two->size);
1785                free(delta);
1786                data = deflated;
1787                data_size = deflate_size;
1788        }
1789
1790        /* emit data encoded in base85 */
1791        cp = data;
1792        while (data_size) {
1793                int bytes = (52 < data_size) ? 52 : data_size;
1794                char line[70];
1795                data_size -= bytes;
1796                if (bytes <= 26)
1797                        line[0] = bytes + 'A' - 1;
1798                else
1799                        line[0] = bytes - 26 + 'a' - 1;
1800                encode_85(line + 1, cp, bytes);
1801                cp = (char *) cp + bytes;
1802                fprintf(file, "%s", prefix);
1803                fputs(line, file);
1804                fputc('\n', file);
1805        }
1806        fprintf(file, "%s\n", prefix);
1807        free(data);
1808}
1809
1810static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1811{
1812        fprintf(file, "%sGIT binary patch\n", prefix);
1813        emit_binary_diff_body(file, one, two, prefix);
1814        emit_binary_diff_body(file, two, one, prefix);
1815}
1816
1817static void diff_filespec_load_driver(struct diff_filespec *one)
1818{
1819        /* Use already-loaded driver */
1820        if (one->driver)
1821                return;
1822
1823        if (S_ISREG(one->mode))
1824                one->driver = userdiff_find_by_path(one->path);
1825
1826        /* Fallback to default settings */
1827        if (!one->driver)
1828                one->driver = userdiff_find_by_name("default");
1829}
1830
1831int diff_filespec_is_binary(struct diff_filespec *one)
1832{
1833        if (one->is_binary == -1) {
1834                diff_filespec_load_driver(one);
1835                if (one->driver->binary != -1)
1836                        one->is_binary = one->driver->binary;
1837                else {
1838                        if (!one->data && DIFF_FILE_VALID(one))
1839                                diff_populate_filespec(one, 0);
1840                        if (one->data)
1841                                one->is_binary = buffer_is_binary(one->data,
1842                                                one->size);
1843                        if (one->is_binary == -1)
1844                                one->is_binary = 0;
1845                }
1846        }
1847        return one->is_binary;
1848}
1849
1850static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
1851{
1852        diff_filespec_load_driver(one);
1853        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
1854}
1855
1856static const char *userdiff_word_regex(struct diff_filespec *one)
1857{
1858        diff_filespec_load_driver(one);
1859        return one->driver->word_regex;
1860}
1861
1862void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
1863{
1864        if (!options->a_prefix)
1865                options->a_prefix = a;
1866        if (!options->b_prefix)
1867                options->b_prefix = b;
1868}
1869
1870struct userdiff_driver *get_textconv(struct diff_filespec *one)
1871{
1872        if (!DIFF_FILE_VALID(one))
1873                return NULL;
1874
1875        diff_filespec_load_driver(one);
1876        if (!one->driver->textconv)
1877                return NULL;
1878
1879        if (one->driver->textconv_want_cache && !one->driver->textconv_cache) {
1880                struct notes_cache *c = xmalloc(sizeof(*c));
1881                struct strbuf name = STRBUF_INIT;
1882
1883                strbuf_addf(&name, "textconv/%s", one->driver->name);
1884                notes_cache_init(c, name.buf, one->driver->textconv);
1885                one->driver->textconv_cache = c;
1886        }
1887
1888        return one->driver;
1889}
1890
1891static void builtin_diff(const char *name_a,
1892                         const char *name_b,
1893                         struct diff_filespec *one,
1894                         struct diff_filespec *two,
1895                         const char *xfrm_msg,
1896                         int must_show_header,
1897                         struct diff_options *o,
1898                         int complete_rewrite)
1899{
1900        mmfile_t mf1, mf2;
1901        const char *lbl[2];
1902        char *a_one, *b_two;
1903        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1904        const char *reset = diff_get_color_opt(o, DIFF_RESET);
1905        const char *a_prefix, *b_prefix;
1906        struct userdiff_driver *textconv_one = NULL;
1907        struct userdiff_driver *textconv_two = NULL;
1908        struct strbuf header = STRBUF_INIT;
1909        struct strbuf *msgbuf;
1910        char *line_prefix = "";
1911
1912        if (o->output_prefix) {
1913                msgbuf = o->output_prefix(o, o->output_prefix_data);
1914                line_prefix = msgbuf->buf;
1915        }
1916
1917        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
1918                        (!one->mode || S_ISGITLINK(one->mode)) &&
1919                        (!two->mode || S_ISGITLINK(two->mode))) {
1920                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
1921                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
1922                show_submodule_summary(o->file, one ? one->path : two->path,
1923                                one->sha1, two->sha1, two->dirty_submodule,
1924                                del, add, reset);
1925                return;
1926        }
1927
1928        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
1929                textconv_one = get_textconv(one);
1930                textconv_two = get_textconv(two);
1931        }
1932
1933        diff_set_mnemonic_prefix(o, "a/", "b/");
1934        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
1935                a_prefix = o->b_prefix;
1936                b_prefix = o->a_prefix;
1937        } else {
1938                a_prefix = o->a_prefix;
1939                b_prefix = o->b_prefix;
1940        }
1941
1942        /* Never use a non-valid filename anywhere if at all possible */
1943        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
1944        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
1945
1946        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
1947        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
1948        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1949        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1950        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
1951        if (lbl[0][0] == '/') {
1952                /* /dev/null */
1953                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
1954                if (xfrm_msg)
1955                        strbuf_addstr(&header, xfrm_msg);
1956                must_show_header = 1;
1957        }
1958        else if (lbl[1][0] == '/') {
1959                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
1960                if (xfrm_msg)
1961                        strbuf_addstr(&header, xfrm_msg);
1962                must_show_header = 1;
1963        }
1964        else {
1965                if (one->mode != two->mode) {
1966                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
1967                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
1968                        must_show_header = 1;
1969                }
1970                if (xfrm_msg)
1971                        strbuf_addstr(&header, xfrm_msg);
1972
1973                /*
1974                 * we do not run diff between different kind
1975                 * of objects.
1976                 */
1977                if ((one->mode ^ two->mode) & S_IFMT)
1978                        goto free_ab_and_return;
1979                if (complete_rewrite &&
1980                    (textconv_one || !diff_filespec_is_binary(one)) &&
1981                    (textconv_two || !diff_filespec_is_binary(two))) {
1982                        fprintf(o->file, "%s", header.buf);
1983                        strbuf_reset(&header);
1984                        emit_rewrite_diff(name_a, name_b, one, two,
1985                                                textconv_one, textconv_two, o);
1986                        o->found_changes = 1;
1987                        goto free_ab_and_return;
1988                }
1989        }
1990
1991        if (o->irreversible_delete && lbl[1][0] == '/') {
1992                fprintf(o->file, "%s", header.buf);
1993                strbuf_reset(&header);
1994                goto free_ab_and_return;
1995        } else if (!DIFF_OPT_TST(o, TEXT) &&
1996            ( (!textconv_one && diff_filespec_is_binary(one)) ||
1997              (!textconv_two && diff_filespec_is_binary(two)) )) {
1998                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1999                        die("unable to read files to diff");
2000                /* Quite common confusing case */
2001                if (mf1.size == mf2.size &&
2002                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2003                        if (must_show_header)
2004                                fprintf(o->file, "%s", header.buf);
2005                        goto free_ab_and_return;
2006                }
2007                fprintf(o->file, "%s", header.buf);
2008                strbuf_reset(&header);
2009                if (DIFF_OPT_TST(o, BINARY))
2010                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2011                else
2012                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2013                                line_prefix, lbl[0], lbl[1]);
2014                o->found_changes = 1;
2015        } else {
2016                /* Crazy xdl interfaces.. */
2017                const char *diffopts = getenv("GIT_DIFF_OPTS");
2018                xpparam_t xpp;
2019                xdemitconf_t xecfg;
2020                struct emit_callback ecbdata;
2021                const struct userdiff_funcname *pe;
2022
2023                if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
2024                        fprintf(o->file, "%s", header.buf);
2025                        strbuf_reset(&header);
2026                }
2027
2028                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2029                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2030
2031                pe = diff_funcname_pattern(one);
2032                if (!pe)
2033                        pe = diff_funcname_pattern(two);
2034
2035                memset(&xpp, 0, sizeof(xpp));
2036                memset(&xecfg, 0, sizeof(xecfg));
2037                memset(&ecbdata, 0, sizeof(ecbdata));
2038                ecbdata.label_path = lbl;
2039                ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
2040                ecbdata.found_changesp = &o->found_changes;
2041                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2042                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2043                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2044                ecbdata.opt = o;
2045                ecbdata.header = header.len ? &header : NULL;
2046                xpp.flags = o->xdl_opts;
2047                xecfg.ctxlen = o->context;
2048                xecfg.interhunkctxlen = o->interhunkcontext;
2049                xecfg.flags = XDL_EMIT_FUNCNAMES;
2050                if (pe)
2051                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2052                if (!diffopts)
2053                        ;
2054                else if (!prefixcmp(diffopts, "--unified="))
2055                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2056                else if (!prefixcmp(diffopts, "-u"))
2057                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2058                if (o->word_diff) {
2059                        int i;
2060
2061                        ecbdata.diff_words =
2062                                xcalloc(1, sizeof(struct diff_words_data));
2063                        ecbdata.diff_words->type = o->word_diff;
2064                        ecbdata.diff_words->opt = o;
2065                        if (!o->word_regex)
2066                                o->word_regex = userdiff_word_regex(one);
2067                        if (!o->word_regex)
2068                                o->word_regex = userdiff_word_regex(two);
2069                        if (!o->word_regex)
2070                                o->word_regex = diff_word_regex_cfg;
2071                        if (o->word_regex) {
2072                                ecbdata.diff_words->word_regex = (regex_t *)
2073                                        xmalloc(sizeof(regex_t));
2074                                if (regcomp(ecbdata.diff_words->word_regex,
2075                                                o->word_regex,
2076                                                REG_EXTENDED | REG_NEWLINE))
2077                                        die ("Invalid regular expression: %s",
2078                                                        o->word_regex);
2079                        }
2080                        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2081                                if (o->word_diff == diff_words_styles[i].type) {
2082                                        ecbdata.diff_words->style =
2083                                                &diff_words_styles[i];
2084                                        break;
2085                                }
2086                        }
2087                        if (DIFF_OPT_TST(o, COLOR_DIFF)) {
2088                                struct diff_words_style *st = ecbdata.diff_words->style;
2089                                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2090                                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2091                                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
2092                        }
2093                }
2094                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2095                              &xpp, &xecfg);
2096                if (o->word_diff)
2097                        free_diff_words_data(&ecbdata);
2098                if (textconv_one)
2099                        free(mf1.ptr);
2100                if (textconv_two)
2101                        free(mf2.ptr);
2102                xdiff_clear_find_func(&xecfg);
2103        }
2104
2105 free_ab_and_return:
2106        strbuf_release(&header);
2107        diff_free_filespec_data(one);
2108        diff_free_filespec_data(two);
2109        free(a_one);
2110        free(b_two);
2111        return;
2112}
2113
2114static void builtin_diffstat(const char *name_a, const char *name_b,
2115                             struct diff_filespec *one,
2116                             struct diff_filespec *two,
2117                             struct diffstat_t *diffstat,
2118                             struct diff_options *o,
2119                             int complete_rewrite)
2120{
2121        mmfile_t mf1, mf2;
2122        struct diffstat_file *data;
2123
2124        data = diffstat_add(diffstat, name_a, name_b);
2125
2126        if (!one || !two) {
2127                data->is_unmerged = 1;
2128                return;
2129        }
2130
2131        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2132                data->is_binary = 1;
2133                data->added = diff_filespec_size(two);
2134                data->deleted = diff_filespec_size(one);
2135        }
2136
2137        else if (complete_rewrite) {
2138                diff_populate_filespec(one, 0);
2139                diff_populate_filespec(two, 0);
2140                data->deleted = count_lines(one->data, one->size);
2141                data->added = count_lines(two->data, two->size);
2142        }
2143
2144        else {
2145                /* Crazy xdl interfaces.. */
2146                xpparam_t xpp;
2147                xdemitconf_t xecfg;
2148
2149                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2150                        die("unable to read files to diff");
2151
2152                memset(&xpp, 0, sizeof(xpp));
2153                memset(&xecfg, 0, sizeof(xecfg));
2154                xpp.flags = o->xdl_opts;
2155                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2156                              &xpp, &xecfg);
2157        }
2158
2159        diff_free_filespec_data(one);
2160        diff_free_filespec_data(two);
2161}
2162
2163static void builtin_checkdiff(const char *name_a, const char *name_b,
2164                              const char *attr_path,
2165                              struct diff_filespec *one,
2166                              struct diff_filespec *two,
2167                              struct diff_options *o)
2168{
2169        mmfile_t mf1, mf2;
2170        struct checkdiff_t data;
2171
2172        if (!two)
2173                return;
2174
2175        memset(&data, 0, sizeof(data));
2176        data.filename = name_b ? name_b : name_a;
2177        data.lineno = 0;
2178        data.o = o;
2179        data.ws_rule = whitespace_rule(attr_path);
2180        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2181
2182        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2183                die("unable to read files to diff");
2184
2185        /*
2186         * All the other codepaths check both sides, but not checking
2187         * the "old" side here is deliberate.  We are checking the newly
2188         * introduced changes, and as long as the "new" side is text, we
2189         * can and should check what it introduces.
2190         */
2191        if (diff_filespec_is_binary(two))
2192                goto free_and_return;
2193        else {
2194                /* Crazy xdl interfaces.. */
2195                xpparam_t xpp;
2196                xdemitconf_t xecfg;
2197
2198                memset(&xpp, 0, sizeof(xpp));
2199                memset(&xecfg, 0, sizeof(xecfg));
2200                xecfg.ctxlen = 1; /* at least one context line */
2201                xpp.flags = 0;
2202                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2203                              &xpp, &xecfg);
2204
2205                if (data.ws_rule & WS_BLANK_AT_EOF) {
2206                        struct emit_callback ecbdata;
2207                        int blank_at_eof;
2208
2209                        ecbdata.ws_rule = data.ws_rule;
2210                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2211                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2212
2213                        if (blank_at_eof) {
2214                                static char *err;
2215                                if (!err)
2216                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2217                                fprintf(o->file, "%s:%d: %s.\n",
2218                                        data.filename, blank_at_eof, err);
2219                                data.status = 1; /* report errors */
2220                        }
2221                }
2222        }
2223 free_and_return:
2224        diff_free_filespec_data(one);
2225        diff_free_filespec_data(two);
2226        if (data.status)
2227                DIFF_OPT_SET(o, CHECK_FAILED);
2228}
2229
2230struct diff_filespec *alloc_filespec(const char *path)
2231{
2232        int namelen = strlen(path);
2233        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2234
2235        memset(spec, 0, sizeof(*spec));
2236        spec->path = (char *)(spec + 1);
2237        memcpy(spec->path, path, namelen+1);
2238        spec->count = 1;
2239        spec->is_binary = -1;
2240        return spec;
2241}
2242
2243void free_filespec(struct diff_filespec *spec)
2244{
2245        if (!--spec->count) {
2246                diff_free_filespec_data(spec);
2247                free(spec);
2248        }
2249}
2250
2251void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2252                   unsigned short mode)
2253{
2254        if (mode) {
2255                spec->mode = canon_mode(mode);
2256                hashcpy(spec->sha1, sha1);
2257                spec->sha1_valid = !is_null_sha1(sha1);
2258        }
2259}
2260
2261/*
2262 * Given a name and sha1 pair, if the index tells us the file in
2263 * the work tree has that object contents, return true, so that
2264 * prepare_temp_file() does not have to inflate and extract.
2265 */
2266static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2267{
2268        struct cache_entry *ce;
2269        struct stat st;
2270        int pos, len;
2271
2272        /*
2273         * We do not read the cache ourselves here, because the
2274         * benchmark with my previous version that always reads cache
2275         * shows that it makes things worse for diff-tree comparing
2276         * two linux-2.6 kernel trees in an already checked out work
2277         * tree.  This is because most diff-tree comparisons deal with
2278         * only a small number of files, while reading the cache is
2279         * expensive for a large project, and its cost outweighs the
2280         * savings we get by not inflating the object to a temporary
2281         * file.  Practically, this code only helps when we are used
2282         * by diff-cache --cached, which does read the cache before
2283         * calling us.
2284         */
2285        if (!active_cache)
2286                return 0;
2287
2288        /* We want to avoid the working directory if our caller
2289         * doesn't need the data in a normal file, this system
2290         * is rather slow with its stat/open/mmap/close syscalls,
2291         * and the object is contained in a pack file.  The pack
2292         * is probably already open and will be faster to obtain
2293         * the data through than the working directory.  Loose
2294         * objects however would tend to be slower as they need
2295         * to be individually opened and inflated.
2296         */
2297        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2298                return 0;
2299
2300        len = strlen(name);
2301        pos = cache_name_pos(name, len);
2302        if (pos < 0)
2303                return 0;
2304        ce = active_cache[pos];
2305
2306        /*
2307         * This is not the sha1 we are looking for, or
2308         * unreusable because it is not a regular file.
2309         */
2310        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2311                return 0;
2312
2313        /*
2314         * If ce is marked as "assume unchanged", there is no
2315         * guarantee that work tree matches what we are looking for.
2316         */
2317        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2318                return 0;
2319
2320        /*
2321         * If ce matches the file in the work tree, we can reuse it.
2322         */
2323        if (ce_uptodate(ce) ||
2324            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2325                return 1;
2326
2327        return 0;
2328}
2329
2330static int populate_from_stdin(struct diff_filespec *s)
2331{
2332        struct strbuf buf = STRBUF_INIT;
2333        size_t size = 0;
2334
2335        if (strbuf_read(&buf, 0, 0) < 0)
2336                return error("error while reading from stdin %s",
2337                                     strerror(errno));
2338
2339        s->should_munmap = 0;
2340        s->data = strbuf_detach(&buf, &size);
2341        s->size = size;
2342        s->should_free = 1;
2343        return 0;
2344}
2345
2346static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2347{
2348        int len;
2349        char *data = xmalloc(100), *dirty = "";
2350
2351        /* Are we looking at the work tree? */
2352        if (s->dirty_submodule)
2353                dirty = "-dirty";
2354
2355        len = snprintf(data, 100,
2356                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2357        s->data = data;
2358        s->size = len;
2359        s->should_free = 1;
2360        if (size_only) {
2361                s->data = NULL;
2362                free(data);
2363        }
2364        return 0;
2365}
2366
2367/*
2368 * While doing rename detection and pickaxe operation, we may need to
2369 * grab the data for the blob (or file) for our own in-core comparison.
2370 * diff_filespec has data and size fields for this purpose.
2371 */
2372int diff_populate_filespec(struct diff_filespec *s, int size_only)
2373{
2374        int err = 0;
2375        if (!DIFF_FILE_VALID(s))
2376                die("internal error: asking to populate invalid file.");
2377        if (S_ISDIR(s->mode))
2378                return -1;
2379
2380        if (s->data)
2381                return 0;
2382
2383        if (size_only && 0 < s->size)
2384                return 0;
2385
2386        if (S_ISGITLINK(s->mode))
2387                return diff_populate_gitlink(s, size_only);
2388
2389        if (!s->sha1_valid ||
2390            reuse_worktree_file(s->path, s->sha1, 0)) {
2391                struct strbuf buf = STRBUF_INIT;
2392                struct stat st;
2393                int fd;
2394
2395                if (!strcmp(s->path, "-"))
2396                        return populate_from_stdin(s);
2397
2398                if (lstat(s->path, &st) < 0) {
2399                        if (errno == ENOENT) {
2400                        err_empty:
2401                                err = -1;
2402                        empty:
2403                                s->data = (char *)"";
2404                                s->size = 0;
2405                                return err;
2406                        }
2407                }
2408                s->size = xsize_t(st.st_size);
2409                if (!s->size)
2410                        goto empty;
2411                if (S_ISLNK(st.st_mode)) {
2412                        struct strbuf sb = STRBUF_INIT;
2413
2414                        if (strbuf_readlink(&sb, s->path, s->size))
2415                                goto err_empty;
2416                        s->size = sb.len;
2417                        s->data = strbuf_detach(&sb, NULL);
2418                        s->should_free = 1;
2419                        return 0;
2420                }
2421                if (size_only)
2422                        return 0;
2423                fd = open(s->path, O_RDONLY);
2424                if (fd < 0)
2425                        goto err_empty;
2426                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2427                close(fd);
2428                s->should_munmap = 1;
2429
2430                /*
2431                 * Convert from working tree format to canonical git format
2432                 */
2433                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2434                        size_t size = 0;
2435                        munmap(s->data, s->size);
2436                        s->should_munmap = 0;
2437                        s->data = strbuf_detach(&buf, &size);
2438                        s->size = size;
2439                        s->should_free = 1;
2440                }
2441        }
2442        else {
2443                enum object_type type;
2444                if (size_only) {
2445                        type = sha1_object_info(s->sha1, &s->size);
2446                        if (type < 0)
2447                                die("unable to read %s", sha1_to_hex(s->sha1));
2448                } else {
2449                        s->data = read_sha1_file(s->sha1, &type, &s->size);
2450                        if (!s->data)
2451                                die("unable to read %s", sha1_to_hex(s->sha1));
2452                        s->should_free = 1;
2453                }
2454        }
2455        return 0;
2456}
2457
2458void diff_free_filespec_blob(struct diff_filespec *s)
2459{
2460        if (s->should_free)
2461                free(s->data);
2462        else if (s->should_munmap)
2463                munmap(s->data, s->size);
2464
2465        if (s->should_free || s->should_munmap) {
2466                s->should_free = s->should_munmap = 0;
2467                s->data = NULL;
2468        }
2469}
2470
2471void diff_free_filespec_data(struct diff_filespec *s)
2472{
2473        diff_free_filespec_blob(s);
2474        free(s->cnt_data);
2475        s->cnt_data = NULL;
2476}
2477
2478static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2479                           void *blob,
2480                           unsigned long size,
2481                           const unsigned char *sha1,
2482                           int mode)
2483{
2484        int fd;
2485        struct strbuf buf = STRBUF_INIT;
2486        struct strbuf template = STRBUF_INIT;
2487        char *path_dup = xstrdup(path);
2488        const char *base = basename(path_dup);
2489
2490        /* Generate "XXXXXX_basename.ext" */
2491        strbuf_addstr(&template, "XXXXXX_");
2492        strbuf_addstr(&template, base);
2493
2494        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2495                        strlen(base) + 1);
2496        if (fd < 0)
2497                die_errno("unable to create temp-file");
2498        if (convert_to_working_tree(path,
2499                        (const char *)blob, (size_t)size, &buf)) {
2500                blob = buf.buf;
2501                size = buf.len;
2502        }
2503        if (write_in_full(fd, blob, size) != size)
2504                die_errno("unable to write temp-file");
2505        close(fd);
2506        temp->name = temp->tmp_path;
2507        strcpy(temp->hex, sha1_to_hex(sha1));
2508        temp->hex[40] = 0;
2509        sprintf(temp->mode, "%06o", mode);
2510        strbuf_release(&buf);
2511        strbuf_release(&template);
2512        free(path_dup);
2513}
2514
2515static struct diff_tempfile *prepare_temp_file(const char *name,
2516                struct diff_filespec *one)
2517{
2518        struct diff_tempfile *temp = claim_diff_tempfile();
2519
2520        if (!DIFF_FILE_VALID(one)) {
2521        not_a_valid_file:
2522                /* A '-' entry produces this for file-2, and
2523                 * a '+' entry produces this for file-1.
2524                 */
2525                temp->name = "/dev/null";
2526                strcpy(temp->hex, ".");
2527                strcpy(temp->mode, ".");
2528                return temp;
2529        }
2530
2531        if (!remove_tempfile_installed) {
2532                atexit(remove_tempfile);
2533                sigchain_push_common(remove_tempfile_on_signal);
2534                remove_tempfile_installed = 1;
2535        }
2536
2537        if (!one->sha1_valid ||
2538            reuse_worktree_file(name, one->sha1, 1)) {
2539                struct stat st;
2540                if (lstat(name, &st) < 0) {
2541                        if (errno == ENOENT)
2542                                goto not_a_valid_file;
2543                        die_errno("stat(%s)", name);
2544                }
2545                if (S_ISLNK(st.st_mode)) {
2546                        struct strbuf sb = STRBUF_INIT;
2547                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2548                                die_errno("readlink(%s)", name);
2549                        prep_temp_blob(name, temp, sb.buf, sb.len,
2550                                       (one->sha1_valid ?
2551                                        one->sha1 : null_sha1),
2552                                       (one->sha1_valid ?
2553                                        one->mode : S_IFLNK));
2554                        strbuf_release(&sb);
2555                }
2556                else {
2557                        /* we can borrow from the file in the work tree */
2558                        temp->name = name;
2559                        if (!one->sha1_valid)
2560                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2561                        else
2562                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2563                        /* Even though we may sometimes borrow the
2564                         * contents from the work tree, we always want
2565                         * one->mode.  mode is trustworthy even when
2566                         * !(one->sha1_valid), as long as
2567                         * DIFF_FILE_VALID(one).
2568                         */
2569                        sprintf(temp->mode, "%06o", one->mode);
2570                }
2571                return temp;
2572        }
2573        else {
2574                if (diff_populate_filespec(one, 0))
2575                        die("cannot read data blob for %s", one->path);
2576                prep_temp_blob(name, temp, one->data, one->size,
2577                               one->sha1, one->mode);
2578        }
2579        return temp;
2580}
2581
2582/* An external diff command takes:
2583 *
2584 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2585 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2586 *
2587 */
2588static void run_external_diff(const char *pgm,
2589                              const char *name,
2590                              const char *other,
2591                              struct diff_filespec *one,
2592                              struct diff_filespec *two,
2593                              const char *xfrm_msg,
2594                              int complete_rewrite)
2595{
2596        const char *spawn_arg[10];
2597        int retval;
2598        const char **arg = &spawn_arg[0];
2599
2600        if (one && two) {
2601                struct diff_tempfile *temp_one, *temp_two;
2602                const char *othername = (other ? other : name);
2603                temp_one = prepare_temp_file(name, one);
2604                temp_two = prepare_temp_file(othername, two);
2605                *arg++ = pgm;
2606                *arg++ = name;
2607                *arg++ = temp_one->name;
2608                *arg++ = temp_one->hex;
2609                *arg++ = temp_one->mode;
2610                *arg++ = temp_two->name;
2611                *arg++ = temp_two->hex;
2612                *arg++ = temp_two->mode;
2613                if (other) {
2614                        *arg++ = other;
2615                        *arg++ = xfrm_msg;
2616                }
2617        } else {
2618                *arg++ = pgm;
2619                *arg++ = name;
2620        }
2621        *arg = NULL;
2622        fflush(NULL);
2623        retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2624        remove_tempfile();
2625        if (retval) {
2626                fprintf(stderr, "external diff died, stopping at %s.\n", name);
2627                exit(1);
2628        }
2629}
2630
2631static int similarity_index(struct diff_filepair *p)
2632{
2633        return p->score * 100 / MAX_SCORE;
2634}
2635
2636static void fill_metainfo(struct strbuf *msg,
2637                          const char *name,
2638                          const char *other,
2639                          struct diff_filespec *one,
2640                          struct diff_filespec *two,
2641                          struct diff_options *o,
2642                          struct diff_filepair *p,
2643                          int *must_show_header,
2644                          int use_color)
2645{
2646        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2647        const char *reset = diff_get_color(use_color, DIFF_RESET);
2648        struct strbuf *msgbuf;
2649        char *line_prefix = "";
2650
2651        *must_show_header = 1;
2652        if (o->output_prefix) {
2653                msgbuf = o->output_prefix(o, o->output_prefix_data);
2654                line_prefix = msgbuf->buf;
2655        }
2656        strbuf_init(msg, PATH_MAX * 2 + 300);
2657        switch (p->status) {
2658        case DIFF_STATUS_COPIED:
2659                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2660                            line_prefix, set, similarity_index(p));
2661                strbuf_addf(msg, "%s\n%s%scopy from ",
2662                            reset,  line_prefix, set);
2663                quote_c_style(name, msg, NULL, 0);
2664                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2665                quote_c_style(other, msg, NULL, 0);
2666                strbuf_addf(msg, "%s\n", reset);
2667                break;
2668        case DIFF_STATUS_RENAMED:
2669                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2670                            line_prefix, set, similarity_index(p));
2671                strbuf_addf(msg, "%s\n%s%srename from ",
2672                            reset, line_prefix, set);
2673                quote_c_style(name, msg, NULL, 0);
2674                strbuf_addf(msg, "%s\n%s%srename to ",
2675                            reset, line_prefix, set);
2676                quote_c_style(other, msg, NULL, 0);
2677                strbuf_addf(msg, "%s\n", reset);
2678                break;
2679        case DIFF_STATUS_MODIFIED:
2680                if (p->score) {
2681                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2682                                    line_prefix,
2683                                    set, similarity_index(p), reset);
2684                        break;
2685                }
2686                /* fallthru */
2687        default:
2688                *must_show_header = 0;
2689        }
2690        if (one && two && hashcmp(one->sha1, two->sha1)) {
2691                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2692
2693                if (DIFF_OPT_TST(o, BINARY)) {
2694                        mmfile_t mf;
2695                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2696                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2697                                abbrev = 40;
2698                }
2699                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2700                            find_unique_abbrev(one->sha1, abbrev));
2701                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2702                if (one->mode == two->mode)
2703                        strbuf_addf(msg, " %06o", one->mode);
2704                strbuf_addf(msg, "%s\n", reset);
2705        }
2706}
2707
2708static void run_diff_cmd(const char *pgm,
2709                         const char *name,
2710                         const char *other,
2711                         const char *attr_path,
2712                         struct diff_filespec *one,
2713                         struct diff_filespec *two,
2714                         struct strbuf *msg,
2715                         struct diff_options *o,
2716                         struct diff_filepair *p)
2717{
2718        const char *xfrm_msg = NULL;
2719        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
2720        int must_show_header = 0;
2721
2722        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2723                pgm = NULL;
2724        else {
2725                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
2726                if (drv && drv->external)
2727                        pgm = drv->external;
2728        }
2729
2730        if (msg) {
2731                /*
2732                 * don't use colors when the header is intended for an
2733                 * external diff driver
2734                 */
2735                fill_metainfo(msg, name, other, one, two, o, p,
2736                              &must_show_header,
2737                              DIFF_OPT_TST(o, COLOR_DIFF) && !pgm);
2738                xfrm_msg = msg->len ? msg->buf : NULL;
2739        }
2740
2741        if (pgm) {
2742                run_external_diff(pgm, name, other, one, two, xfrm_msg,
2743                                  complete_rewrite);
2744                return;
2745        }
2746        if (one && two)
2747                builtin_diff(name, other ? other : name,
2748                             one, two, xfrm_msg, must_show_header,
2749                             o, complete_rewrite);
2750        else
2751                fprintf(o->file, "* Unmerged path %s\n", name);
2752}
2753
2754static void diff_fill_sha1_info(struct diff_filespec *one)
2755{
2756        if (DIFF_FILE_VALID(one)) {
2757                if (!one->sha1_valid) {
2758                        struct stat st;
2759                        if (!strcmp(one->path, "-")) {
2760                                hashcpy(one->sha1, null_sha1);
2761                                return;
2762                        }
2763                        if (lstat(one->path, &st) < 0)
2764                                die_errno("stat '%s'", one->path);
2765                        if (index_path(one->sha1, one->path, &st, 0))
2766                                die("cannot hash %s", one->path);
2767                }
2768        }
2769        else
2770                hashclr(one->sha1);
2771}
2772
2773static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2774{
2775        /* Strip the prefix but do not molest /dev/null and absolute paths */
2776        if (*namep && **namep != '/') {
2777                *namep += prefix_length;
2778                if (**namep == '/')
2779                        ++*namep;
2780        }
2781        if (*otherp && **otherp != '/') {
2782                *otherp += prefix_length;
2783                if (**otherp == '/')
2784                        ++*otherp;
2785        }
2786}
2787
2788static void run_diff(struct diff_filepair *p, struct diff_options *o)
2789{
2790        const char *pgm = external_diff();
2791        struct strbuf msg;
2792        struct diff_filespec *one = p->one;
2793        struct diff_filespec *two = p->two;
2794        const char *name;
2795        const char *other;
2796        const char *attr_path;
2797
2798        name  = p->one->path;
2799        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2800        attr_path = name;
2801        if (o->prefix_length)
2802                strip_prefix(o->prefix_length, &name, &other);
2803
2804        if (DIFF_PAIR_UNMERGED(p)) {
2805                run_diff_cmd(pgm, name, NULL, attr_path,
2806                             NULL, NULL, NULL, o, p);
2807                return;
2808        }
2809
2810        diff_fill_sha1_info(one);
2811        diff_fill_sha1_info(two);
2812
2813        if (!pgm &&
2814            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2815            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2816                /*
2817                 * a filepair that changes between file and symlink
2818                 * needs to be split into deletion and creation.
2819                 */
2820                struct diff_filespec *null = alloc_filespec(two->path);
2821                run_diff_cmd(NULL, name, other, attr_path,
2822                             one, null, &msg, o, p);
2823                free(null);
2824                strbuf_release(&msg);
2825
2826                null = alloc_filespec(one->path);
2827                run_diff_cmd(NULL, name, other, attr_path,
2828                             null, two, &msg, o, p);
2829                free(null);
2830        }
2831        else
2832                run_diff_cmd(pgm, name, other, attr_path,
2833                             one, two, &msg, o, p);
2834
2835        strbuf_release(&msg);
2836}
2837
2838static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2839                         struct diffstat_t *diffstat)
2840{
2841        const char *name;
2842        const char *other;
2843        int complete_rewrite = 0;
2844
2845        if (DIFF_PAIR_UNMERGED(p)) {
2846                /* unmerged */
2847                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2848                return;
2849        }
2850
2851        name = p->one->path;
2852        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2853
2854        if (o->prefix_length)
2855                strip_prefix(o->prefix_length, &name, &other);
2856
2857        diff_fill_sha1_info(p->one);
2858        diff_fill_sha1_info(p->two);
2859
2860        if (p->status == DIFF_STATUS_MODIFIED && p->score)
2861                complete_rewrite = 1;
2862        builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2863}
2864
2865static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2866{
2867        const char *name;
2868        const char *other;
2869        const char *attr_path;
2870
2871        if (DIFF_PAIR_UNMERGED(p)) {
2872                /* unmerged */
2873                return;
2874        }
2875
2876        name = p->one->path;
2877        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2878        attr_path = other ? other : name;
2879
2880        if (o->prefix_length)
2881                strip_prefix(o->prefix_length, &name, &other);
2882
2883        diff_fill_sha1_info(p->one);
2884        diff_fill_sha1_info(p->two);
2885
2886        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2887}
2888
2889void diff_setup(struct diff_options *options)
2890{
2891        memcpy(options, &default_diff_options, sizeof(*options));
2892
2893        options->file = stdout;
2894
2895        options->line_termination = '\n';
2896        options->break_opt = -1;
2897        options->rename_limit = -1;
2898        options->dirstat_percent = 3;
2899        options->context = 3;
2900
2901        options->change = diff_change;
2902        options->add_remove = diff_addremove;
2903        if (diff_use_color_default > 0)
2904                DIFF_OPT_SET(options, COLOR_DIFF);
2905        options->detect_rename = diff_detect_rename_default;
2906
2907        if (diff_no_prefix) {
2908                options->a_prefix = options->b_prefix = "";
2909        } else if (!diff_mnemonic_prefix) {
2910                options->a_prefix = "a/";
2911                options->b_prefix = "b/";
2912        }
2913}
2914
2915int diff_setup_done(struct diff_options *options)
2916{
2917        int count = 0;
2918
2919        if (options->output_format & DIFF_FORMAT_NAME)
2920                count++;
2921        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2922                count++;
2923        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2924                count++;
2925        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2926                count++;
2927        if (count > 1)
2928                die("--name-only, --name-status, --check and -s are mutually exclusive");
2929
2930        /*
2931         * Most of the time we can say "there are changes"
2932         * only by checking if there are changed paths, but
2933         * --ignore-whitespace* options force us to look
2934         * inside contents.
2935         */
2936
2937        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
2938            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
2939            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
2940                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
2941        else
2942                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
2943
2944        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2945                options->detect_rename = DIFF_DETECT_COPY;
2946
2947        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2948                options->prefix = NULL;
2949        if (options->prefix)
2950                options->prefix_length = strlen(options->prefix);
2951        else
2952                options->prefix_length = 0;
2953
2954        if (options->output_format & (DIFF_FORMAT_NAME |
2955                                      DIFF_FORMAT_NAME_STATUS |
2956                                      DIFF_FORMAT_CHECKDIFF |
2957                                      DIFF_FORMAT_NO_OUTPUT))
2958                options->output_format &= ~(DIFF_FORMAT_RAW |
2959                                            DIFF_FORMAT_NUMSTAT |
2960                                            DIFF_FORMAT_DIFFSTAT |
2961                                            DIFF_FORMAT_SHORTSTAT |
2962                                            DIFF_FORMAT_DIRSTAT |
2963                                            DIFF_FORMAT_SUMMARY |
2964                                            DIFF_FORMAT_PATCH);
2965
2966        /*
2967         * These cases always need recursive; we do not drop caller-supplied
2968         * recursive bits for other formats here.
2969         */
2970        if (options->output_format & (DIFF_FORMAT_PATCH |
2971                                      DIFF_FORMAT_NUMSTAT |
2972                                      DIFF_FORMAT_DIFFSTAT |
2973                                      DIFF_FORMAT_SHORTSTAT |
2974                                      DIFF_FORMAT_DIRSTAT |
2975                                      DIFF_FORMAT_SUMMARY |
2976                                      DIFF_FORMAT_CHECKDIFF))
2977                DIFF_OPT_SET(options, RECURSIVE);
2978        /*
2979         * Also pickaxe would not work very well if you do not say recursive
2980         */
2981        if (options->pickaxe)
2982                DIFF_OPT_SET(options, RECURSIVE);
2983        /*
2984         * When patches are generated, submodules diffed against the work tree
2985         * must be checked for dirtiness too so it can be shown in the output
2986         */
2987        if (options->output_format & DIFF_FORMAT_PATCH)
2988                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
2989
2990        if (options->detect_rename && options->rename_limit < 0)
2991                options->rename_limit = diff_rename_limit_default;
2992        if (options->setup & DIFF_SETUP_USE_CACHE) {
2993                if (!active_cache)
2994                        /* read-cache does not die even when it fails
2995                         * so it is safe for us to do this here.  Also
2996                         * it does not smudge active_cache or active_nr
2997                         * when it fails, so we do not have to worry about
2998                         * cleaning it up ourselves either.
2999                         */
3000                        read_cache();
3001        }
3002        if (options->abbrev <= 0 || 40 < options->abbrev)
3003                options->abbrev = 40; /* full */
3004
3005        /*
3006         * It does not make sense to show the first hit we happened
3007         * to have found.  It does not make sense not to return with
3008         * exit code in such a case either.
3009         */
3010        if (DIFF_OPT_TST(options, QUICK)) {
3011                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3012                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3013        }
3014
3015        return 0;
3016}
3017
3018static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3019{
3020        char c, *eq;
3021        int len;
3022
3023        if (*arg != '-')
3024                return 0;
3025        c = *++arg;
3026        if (!c)
3027                return 0;
3028        if (c == arg_short) {
3029                c = *++arg;
3030                if (!c)
3031                        return 1;
3032                if (val && isdigit(c)) {
3033                        char *end;
3034                        int n = strtoul(arg, &end, 10);
3035                        if (*end)
3036                                return 0;
3037                        *val = n;
3038                        return 1;
3039                }
3040                return 0;
3041        }
3042        if (c != '-')
3043                return 0;
3044        arg++;
3045        eq = strchr(arg, '=');
3046        if (eq)
3047                len = eq - arg;
3048        else
3049                len = strlen(arg);
3050        if (!len || strncmp(arg, arg_long, len))
3051                return 0;
3052        if (eq) {
3053                int n;
3054                char *end;
3055                if (!isdigit(*++eq))
3056                        return 0;
3057                n = strtoul(eq, &end, 10);
3058                if (*end)
3059                        return 0;
3060                *val = n;
3061        }
3062        return 1;
3063}
3064
3065static int diff_scoreopt_parse(const char *opt);
3066
3067static inline int short_opt(char opt, const char **argv,
3068                            const char **optarg)
3069{
3070        const char *arg = argv[0];
3071        if (arg[0] != '-' || arg[1] != opt)
3072                return 0;
3073        if (arg[2] != '\0') {
3074                *optarg = arg + 2;
3075                return 1;
3076        }
3077        if (!argv[1])
3078                die("Option '%c' requires a value", opt);
3079        *optarg = argv[1];
3080        return 2;
3081}
3082
3083int parse_long_opt(const char *opt, const char **argv,
3084                   const char **optarg)
3085{
3086        const char *arg = argv[0];
3087        if (arg[0] != '-' || arg[1] != '-')
3088                return 0;
3089        arg += strlen("--");
3090        if (prefixcmp(arg, opt))
3091                return 0;
3092        arg += strlen(opt);
3093        if (*arg == '=') { /* sticked form: --option=value */
3094                *optarg = arg + 1;
3095                return 1;
3096        }
3097        if (*arg != '\0')
3098                return 0;
3099        /* separate form: --option value */
3100        if (!argv[1])
3101                die("Option '--%s' requires a value", opt);
3102        *optarg = argv[1];
3103        return 2;
3104}
3105
3106static int stat_opt(struct diff_options *options, const char **av)
3107{
3108        const char *arg = av[0];
3109        char *end;
3110        int width = options->stat_width;
3111        int name_width = options->stat_name_width;
3112        int argcount = 1;
3113
3114        arg += strlen("--stat");
3115        end = (char *)arg;
3116
3117        switch (*arg) {
3118        case '-':
3119                if (!prefixcmp(arg, "-width")) {
3120                        arg += strlen("-width");
3121                        if (*arg == '=')
3122                                width = strtoul(arg + 1, &end, 10);
3123                        else if (!*arg && !av[1])
3124                                die("Option '--stat-width' requires a value");
3125                        else if (!*arg) {
3126                                width = strtoul(av[1], &end, 10);
3127                                argcount = 2;
3128                        }
3129                } else if (!prefixcmp(arg, "-name-width")) {
3130                        arg += strlen("-name-width");
3131                        if (*arg == '=')
3132                                name_width = strtoul(arg + 1, &end, 10);
3133                        else if (!*arg && !av[1])
3134                                die("Option '--stat-name-width' requires a value");
3135                        else if (!*arg) {
3136                                name_width = strtoul(av[1], &end, 10);
3137                                argcount = 2;
3138                        }
3139                }
3140                break;
3141        case '=':
3142                width = strtoul(arg+1, &end, 10);
3143                if (*end == ',')
3144                        name_width = strtoul(end+1, &end, 10);
3145        }
3146
3147        /* Important! This checks all the error cases! */
3148        if (*end)
3149                return 0;
3150        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3151        options->stat_name_width = name_width;
3152        options->stat_width = width;
3153        return argcount;
3154}
3155
3156int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3157{
3158        const char *arg = av[0];
3159        const char *optarg;
3160        int argcount;
3161
3162        /* Output format options */
3163        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3164                options->output_format |= DIFF_FORMAT_PATCH;
3165        else if (opt_arg(arg, 'U', "unified", &options->context))
3166                options->output_format |= DIFF_FORMAT_PATCH;
3167        else if (!strcmp(arg, "--raw"))
3168                options->output_format |= DIFF_FORMAT_RAW;
3169        else if (!strcmp(arg, "--patch-with-raw"))
3170                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3171        else if (!strcmp(arg, "--numstat"))
3172                options->output_format |= DIFF_FORMAT_NUMSTAT;
3173        else if (!strcmp(arg, "--shortstat"))
3174                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3175        else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
3176                options->output_format |= DIFF_FORMAT_DIRSTAT;
3177        else if (!strcmp(arg, "--cumulative")) {
3178                options->output_format |= DIFF_FORMAT_DIRSTAT;
3179                DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
3180        } else if (opt_arg(arg, 0, "dirstat-by-file",
3181                           &options->dirstat_percent)) {
3182                options->output_format |= DIFF_FORMAT_DIRSTAT;
3183                DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
3184        }
3185        else if (!strcmp(arg, "--check"))
3186                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3187        else if (!strcmp(arg, "--summary"))
3188                options->output_format |= DIFF_FORMAT_SUMMARY;
3189        else if (!strcmp(arg, "--patch-with-stat"))
3190                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3191        else if (!strcmp(arg, "--name-only"))
3192                options->output_format |= DIFF_FORMAT_NAME;
3193        else if (!strcmp(arg, "--name-status"))
3194                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3195        else if (!strcmp(arg, "-s"))
3196                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3197        else if (!prefixcmp(arg, "--stat"))
3198                /* --stat, --stat-width, or --stat-name-width */
3199                return stat_opt(options, av);
3200
3201        /* renames options */
3202        else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3203                 !strcmp(arg, "--break-rewrites")) {
3204                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3205                        return error("invalid argument to -B: %s", arg+2);
3206        }
3207        else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3208                 !strcmp(arg, "--find-renames")) {
3209                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3210                        return error("invalid argument to -M: %s", arg+2);
3211                options->detect_rename = DIFF_DETECT_RENAME;
3212        }
3213        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3214                options->irreversible_delete = 1;
3215        }
3216        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3217                 !strcmp(arg, "--find-copies")) {
3218                if (options->detect_rename == DIFF_DETECT_COPY)
3219                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3220                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3221                        return error("invalid argument to -C: %s", arg+2);
3222                options->detect_rename = DIFF_DETECT_COPY;
3223        }
3224        else if (!strcmp(arg, "--no-renames"))
3225                options->detect_rename = 0;
3226        else if (!strcmp(arg, "--relative"))
3227                DIFF_OPT_SET(options, RELATIVE_NAME);
3228        else if (!prefixcmp(arg, "--relative=")) {
3229                DIFF_OPT_SET(options, RELATIVE_NAME);
3230                options->prefix = arg + 11;
3231        }
3232
3233        /* xdiff options */
3234        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3235                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3236        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3237                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3238        else if (!strcmp(arg, "--ignore-space-at-eol"))
3239                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3240        else if (!strcmp(arg, "--patience"))
3241                DIFF_XDL_SET(options, PATIENCE_DIFF);
3242
3243        /* flags options */
3244        else if (!strcmp(arg, "--binary")) {
3245                options->output_format |= DIFF_FORMAT_PATCH;
3246                DIFF_OPT_SET(options, BINARY);
3247        }
3248        else if (!strcmp(arg, "--full-index"))
3249                DIFF_OPT_SET(options, FULL_INDEX);
3250        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3251                DIFF_OPT_SET(options, TEXT);
3252        else if (!strcmp(arg, "-R"))
3253                DIFF_OPT_SET(options, REVERSE_DIFF);
3254        else if (!strcmp(arg, "--find-copies-harder"))
3255                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3256        else if (!strcmp(arg, "--follow"))
3257                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3258        else if (!strcmp(arg, "--color"))
3259                DIFF_OPT_SET(options, COLOR_DIFF);
3260        else if (!prefixcmp(arg, "--color=")) {
3261                int value = git_config_colorbool(NULL, arg+8, -1);
3262                if (value == 0)
3263                        DIFF_OPT_CLR(options, COLOR_DIFF);
3264                else if (value > 0)
3265                        DIFF_OPT_SET(options, COLOR_DIFF);
3266                else
3267                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3268        }
3269        else if (!strcmp(arg, "--no-color"))
3270                DIFF_OPT_CLR(options, COLOR_DIFF);
3271        else if (!strcmp(arg, "--color-words")) {
3272                DIFF_OPT_SET(options, COLOR_DIFF);
3273                options->word_diff = DIFF_WORDS_COLOR;
3274        }
3275        else if (!prefixcmp(arg, "--color-words=")) {
3276                DIFF_OPT_SET(options, COLOR_DIFF);
3277                options->word_diff = DIFF_WORDS_COLOR;
3278                options->word_regex = arg + 14;
3279        }
3280        else if (!strcmp(arg, "--word-diff")) {
3281                if (options->word_diff == DIFF_WORDS_NONE)
3282                        options->word_diff = DIFF_WORDS_PLAIN;
3283        }
3284        else if (!prefixcmp(arg, "--word-diff=")) {
3285                const char *type = arg + 12;
3286                if (!strcmp(type, "plain"))
3287                        options->word_diff = DIFF_WORDS_PLAIN;
3288                else if (!strcmp(type, "color")) {
3289                        DIFF_OPT_SET(options, COLOR_DIFF);
3290                        options->word_diff = DIFF_WORDS_COLOR;
3291                }
3292                else if (!strcmp(type, "porcelain"))
3293                        options->word_diff = DIFF_WORDS_PORCELAIN;
3294                else if (!strcmp(type, "none"))
3295                        options->word_diff = DIFF_WORDS_NONE;
3296                else
3297                        die("bad --word-diff argument: %s", type);
3298        }
3299        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3300                if (options->word_diff == DIFF_WORDS_NONE)
3301                        options->word_diff = DIFF_WORDS_PLAIN;
3302                options->word_regex = optarg;
3303                return argcount;
3304        }
3305        else if (!strcmp(arg, "--exit-code"))
3306                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3307        else if (!strcmp(arg, "--quiet"))
3308                DIFF_OPT_SET(options, QUICK);
3309        else if (!strcmp(arg, "--ext-diff"))
3310                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3311        else if (!strcmp(arg, "--no-ext-diff"))
3312                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3313        else if (!strcmp(arg, "--textconv"))
3314                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3315        else if (!strcmp(arg, "--no-textconv"))
3316                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3317        else if (!strcmp(arg, "--ignore-submodules")) {
3318                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3319                handle_ignore_submodules_arg(options, "all");
3320        } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3321                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3322                handle_ignore_submodules_arg(options, arg + 20);
3323        } else if (!strcmp(arg, "--submodule"))
3324                DIFF_OPT_SET(options, SUBMODULE_LOG);
3325        else if (!prefixcmp(arg, "--submodule=")) {
3326                if (!strcmp(arg + 12, "log"))
3327                        DIFF_OPT_SET(options, SUBMODULE_LOG);
3328        }
3329
3330        /* misc options */
3331        else if (!strcmp(arg, "-z"))
3332                options->line_termination = 0;
3333        else if ((argcount = short_opt('l', av, &optarg))) {
3334                options->rename_limit = strtoul(optarg, NULL, 10);
3335                return argcount;
3336        }
3337        else if ((argcount = short_opt('S', av, &optarg))) {
3338                options->pickaxe = optarg;
3339                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3340                return argcount;
3341        } else if ((argcount = short_opt('G', av, &optarg))) {
3342                options->pickaxe = optarg;
3343                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3344                return argcount;
3345        }
3346        else if (!strcmp(arg, "--pickaxe-all"))
3347                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3348        else if (!strcmp(arg, "--pickaxe-regex"))
3349                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3350        else if ((argcount = short_opt('O', av, &optarg))) {
3351                options->orderfile = optarg;
3352                return argcount;
3353        }
3354        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3355                options->filter = optarg;
3356                return argcount;
3357        }
3358        else if (!strcmp(arg, "--abbrev"))
3359                options->abbrev = DEFAULT_ABBREV;
3360        else if (!prefixcmp(arg, "--abbrev=")) {
3361                options->abbrev = strtoul(arg + 9, NULL, 10);
3362                if (options->abbrev < MINIMUM_ABBREV)
3363                        options->abbrev = MINIMUM_ABBREV;
3364                else if (40 < options->abbrev)
3365                        options->abbrev = 40;
3366        }
3367        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3368                options->a_prefix = optarg;
3369                return argcount;
3370        }
3371        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3372                options->b_prefix = optarg;
3373                return argcount;
3374        }
3375        else if (!strcmp(arg, "--no-prefix"))
3376                options->a_prefix = options->b_prefix = "";
3377        else if (opt_arg(arg, '\0', "inter-hunk-context",
3378                         &options->interhunkcontext))
3379                ;
3380        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3381                options->file = fopen(optarg, "w");
3382                if (!options->file)
3383                        die_errno("Could not open '%s'", optarg);
3384                options->close_file = 1;
3385                return argcount;
3386        } else
3387                return 0;
3388        return 1;
3389}
3390
3391int parse_rename_score(const char **cp_p)
3392{
3393        unsigned long num, scale;
3394        int ch, dot;
3395        const char *cp = *cp_p;
3396
3397        num = 0;
3398        scale = 1;
3399        dot = 0;
3400        for (;;) {
3401                ch = *cp;
3402                if ( !dot && ch == '.' ) {
3403                        scale = 1;
3404                        dot = 1;
3405                } else if ( ch == '%' ) {
3406                        scale = dot ? scale*100 : 100;
3407                        cp++;   /* % is always at the end */
3408                        break;
3409                } else if ( ch >= '0' && ch <= '9' ) {
3410                        if ( scale < 100000 ) {
3411                                scale *= 10;
3412                                num = (num*10) + (ch-'0');
3413                        }
3414                } else {
3415                        break;
3416                }
3417                cp++;
3418        }
3419        *cp_p = cp;
3420
3421        /* user says num divided by scale and we say internally that
3422         * is MAX_SCORE * num / scale.
3423         */
3424        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3425}
3426
3427static int diff_scoreopt_parse(const char *opt)
3428{
3429        int opt1, opt2, cmd;
3430
3431        if (*opt++ != '-')
3432                return -1;
3433        cmd = *opt++;
3434        if (cmd == '-') {
3435                /* convert the long-form arguments into short-form versions */
3436                if (!prefixcmp(opt, "break-rewrites")) {
3437                        opt += strlen("break-rewrites");
3438                        if (*opt == 0 || *opt++ == '=')
3439                                cmd = 'B';
3440                } else if (!prefixcmp(opt, "find-copies")) {
3441                        opt += strlen("find-copies");
3442                        if (*opt == 0 || *opt++ == '=')
3443                                cmd = 'C';
3444                } else if (!prefixcmp(opt, "find-renames")) {
3445                        opt += strlen("find-renames");
3446                        if (*opt == 0 || *opt++ == '=')
3447                                cmd = 'M';
3448                }
3449        }
3450        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3451                return -1; /* that is not a -M, -C nor -B option */
3452
3453        opt1 = parse_rename_score(&opt);
3454        if (cmd != 'B')
3455                opt2 = 0;
3456        else {
3457                if (*opt == 0)
3458                        opt2 = 0;
3459                else if (*opt != '/')
3460                        return -1; /* we expect -B80/99 or -B80 */
3461                else {
3462                        opt++;
3463                        opt2 = parse_rename_score(&opt);
3464                }
3465        }
3466        if (*opt != 0)
3467                return -1;
3468        return opt1 | (opt2 << 16);
3469}
3470
3471struct diff_queue_struct diff_queued_diff;
3472
3473void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3474{
3475        if (queue->alloc <= queue->nr) {
3476                queue->alloc = alloc_nr(queue->alloc);
3477                queue->queue = xrealloc(queue->queue,
3478                                        sizeof(dp) * queue->alloc);
3479        }
3480        queue->queue[queue->nr++] = dp;
3481}
3482
3483struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3484                                 struct diff_filespec *one,
3485                                 struct diff_filespec *two)
3486{
3487        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3488        dp->one = one;
3489        dp->two = two;
3490        if (queue)
3491                diff_q(queue, dp);
3492        return dp;
3493}
3494
3495void diff_free_filepair(struct diff_filepair *p)
3496{
3497        free_filespec(p->one);
3498        free_filespec(p->two);
3499        free(p);
3500}
3501
3502/* This is different from find_unique_abbrev() in that
3503 * it stuffs the result with dots for alignment.
3504 */
3505const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3506{
3507        int abblen;
3508        const char *abbrev;
3509        if (len == 40)
3510                return sha1_to_hex(sha1);
3511
3512        abbrev = find_unique_abbrev(sha1, len);
3513        abblen = strlen(abbrev);
3514        if (abblen < 37) {
3515                static char hex[41];
3516                if (len < abblen && abblen <= len + 2)
3517                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3518                else
3519                        sprintf(hex, "%s...", abbrev);
3520                return hex;
3521        }
3522        return sha1_to_hex(sha1);
3523}
3524
3525static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3526{
3527        int line_termination = opt->line_termination;
3528        int inter_name_termination = line_termination ? '\t' : '\0';
3529        if (opt->output_prefix) {
3530                struct strbuf *msg = NULL;
3531                msg = opt->output_prefix(opt, opt->output_prefix_data);
3532                fprintf(opt->file, "%s", msg->buf);
3533        }
3534
3535        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3536                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3537                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
3538                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3539        }
3540        if (p->score) {
3541                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3542                        inter_name_termination);
3543        } else {
3544                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3545        }
3546
3547        if (p->status == DIFF_STATUS_COPIED ||
3548            p->status == DIFF_STATUS_RENAMED) {
3549                const char *name_a, *name_b;
3550                name_a = p->one->path;
3551                name_b = p->two->path;
3552                strip_prefix(opt->prefix_length, &name_a, &name_b);
3553                write_name_quoted(name_a, opt->file, inter_name_termination);
3554                write_name_quoted(name_b, opt->file, line_termination);
3555        } else {
3556                const char *name_a, *name_b;
3557                name_a = p->one->mode ? p->one->path : p->two->path;
3558                name_b = NULL;
3559                strip_prefix(opt->prefix_length, &name_a, &name_b);
3560                write_name_quoted(name_a, opt->file, line_termination);
3561        }
3562}
3563
3564int diff_unmodified_pair(struct diff_filepair *p)
3565{
3566        /* This function is written stricter than necessary to support
3567         * the currently implemented transformers, but the idea is to
3568         * let transformers to produce diff_filepairs any way they want,
3569         * and filter and clean them up here before producing the output.
3570         */
3571        struct diff_filespec *one = p->one, *two = p->two;
3572
3573        if (DIFF_PAIR_UNMERGED(p))
3574                return 0; /* unmerged is interesting */
3575
3576        /* deletion, addition, mode or type change
3577         * and rename are all interesting.
3578         */
3579        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3580            DIFF_PAIR_MODE_CHANGED(p) ||
3581            strcmp(one->path, two->path))
3582                return 0;
3583
3584        /* both are valid and point at the same path.  that is, we are
3585         * dealing with a change.
3586         */
3587        if (one->sha1_valid && two->sha1_valid &&
3588            !hashcmp(one->sha1, two->sha1) &&
3589            !one->dirty_submodule && !two->dirty_submodule)
3590                return 1; /* no change */
3591        if (!one->sha1_valid && !two->sha1_valid)
3592                return 1; /* both look at the same file on the filesystem. */
3593        return 0;
3594}
3595
3596static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3597{
3598        if (diff_unmodified_pair(p))
3599                return;
3600
3601        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3602            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3603                return; /* no tree diffs in patch format */
3604
3605        run_diff(p, o);
3606}
3607
3608static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3609                            struct diffstat_t *diffstat)
3610{
3611        if (diff_unmodified_pair(p))
3612                return;
3613
3614        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3615            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3616                return; /* no useful stat for tree diffs */
3617
3618        run_diffstat(p, o, diffstat);
3619}
3620
3621static void diff_flush_checkdiff(struct diff_filepair *p,
3622                struct diff_options *o)
3623{
3624        if (diff_unmodified_pair(p))
3625                return;
3626
3627        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3628            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3629                return; /* nothing to check in tree diffs */
3630
3631        run_checkdiff(p, o);
3632}
3633
3634int diff_queue_is_empty(void)
3635{
3636        struct diff_queue_struct *q = &diff_queued_diff;
3637        int i;
3638        for (i = 0; i < q->nr; i++)
3639                if (!diff_unmodified_pair(q->queue[i]))
3640                        return 0;
3641        return 1;
3642}
3643
3644#if DIFF_DEBUG
3645void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
3646{
3647        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
3648                x, one ? one : "",
3649                s->path,
3650                DIFF_FILE_VALID(s) ? "valid" : "invalid",
3651                s->mode,
3652                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
3653        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
3654                x, one ? one : "",
3655                s->size, s->xfrm_flags);
3656}
3657
3658void diff_debug_filepair(const struct diff_filepair *p, int i)
3659{
3660        diff_debug_filespec(p->one, i, "one");
3661        diff_debug_filespec(p->two, i, "two");
3662        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
3663                p->score, p->status ? p->status : '?',
3664                p->one->rename_used, p->broken_pair);
3665}
3666
3667void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
3668{
3669        int i;
3670        if (msg)
3671                fprintf(stderr, "%s\n", msg);
3672        fprintf(stderr, "q->nr = %d\n", q->nr);
3673        for (i = 0; i < q->nr; i++) {
3674                struct diff_filepair *p = q->queue[i];
3675                diff_debug_filepair(p, i);
3676        }
3677}
3678#endif
3679
3680static void diff_resolve_rename_copy(void)
3681{
3682        int i;
3683        struct diff_filepair *p;
3684        struct diff_queue_struct *q = &diff_queued_diff;
3685
3686        diff_debug_queue("resolve-rename-copy", q);
3687
3688        for (i = 0; i < q->nr; i++) {
3689                p = q->queue[i];
3690                p->status = 0; /* undecided */
3691                if (DIFF_PAIR_UNMERGED(p))
3692                        p->status = DIFF_STATUS_UNMERGED;
3693                else if (!DIFF_FILE_VALID(p->one))
3694                        p->status = DIFF_STATUS_ADDED;
3695                else if (!DIFF_FILE_VALID(p->two))
3696                        p->status = DIFF_STATUS_DELETED;
3697                else if (DIFF_PAIR_TYPE_CHANGED(p))
3698                        p->status = DIFF_STATUS_TYPE_CHANGED;
3699
3700                /* from this point on, we are dealing with a pair
3701                 * whose both sides are valid and of the same type, i.e.
3702                 * either in-place edit or rename/copy edit.
3703                 */
3704                else if (DIFF_PAIR_RENAME(p)) {
3705                        /*
3706                         * A rename might have re-connected a broken
3707                         * pair up, causing the pathnames to be the
3708                         * same again. If so, that's not a rename at
3709                         * all, just a modification..
3710                         *
3711                         * Otherwise, see if this source was used for
3712                         * multiple renames, in which case we decrement
3713                         * the count, and call it a copy.
3714                         */
3715                        if (!strcmp(p->one->path, p->two->path))
3716                                p->status = DIFF_STATUS_MODIFIED;
3717                        else if (--p->one->rename_used > 0)
3718                                p->status = DIFF_STATUS_COPIED;
3719                        else
3720                                p->status = DIFF_STATUS_RENAMED;
3721                }
3722                else if (hashcmp(p->one->sha1, p->two->sha1) ||
3723                         p->one->mode != p->two->mode ||
3724                         p->one->dirty_submodule ||
3725                         p->two->dirty_submodule ||
3726                         is_null_sha1(p->one->sha1))
3727                        p->status = DIFF_STATUS_MODIFIED;
3728                else {
3729                        /* This is a "no-change" entry and should not
3730                         * happen anymore, but prepare for broken callers.
3731                         */
3732                        error("feeding unmodified %s to diffcore",
3733                              p->one->path);
3734                        p->status = DIFF_STATUS_UNKNOWN;
3735                }
3736        }
3737        diff_debug_queue("resolve-rename-copy done", q);
3738}
3739
3740static int check_pair_status(struct diff_filepair *p)
3741{
3742        switch (p->status) {
3743        case DIFF_STATUS_UNKNOWN:
3744                return 0;
3745        case 0:
3746                die("internal error in diff-resolve-rename-copy");
3747        default:
3748                return 1;
3749        }
3750}
3751
3752static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
3753{
3754        int fmt = opt->output_format;
3755
3756        if (fmt & DIFF_FORMAT_CHECKDIFF)
3757                diff_flush_checkdiff(p, opt);
3758        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
3759                diff_flush_raw(p, opt);
3760        else if (fmt & DIFF_FORMAT_NAME) {
3761                const char *name_a, *name_b;
3762                name_a = p->two->path;
3763                name_b = NULL;
3764                strip_prefix(opt->prefix_length, &name_a, &name_b);
3765                write_name_quoted(name_a, opt->file, opt->line_termination);
3766        }
3767}
3768
3769static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
3770{
3771        if (fs->mode)
3772                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
3773        else
3774                fprintf(file, " %s ", newdelete);
3775        write_name_quoted(fs->path, file, '\n');
3776}
3777
3778
3779static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
3780                const char *line_prefix)
3781{
3782        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
3783                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
3784                        p->two->mode, show_name ? ' ' : '\n');
3785                if (show_name) {
3786                        write_name_quoted(p->two->path, file, '\n');
3787                }
3788        }
3789}
3790
3791static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
3792                        const char *line_prefix)
3793{
3794        char *names = pprint_rename(p->one->path, p->two->path);
3795
3796        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3797        free(names);
3798        show_mode_change(file, p, 0, line_prefix);
3799}
3800
3801static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
3802{
3803        FILE *file = opt->file;
3804        char *line_prefix = "";
3805
3806        if (opt->output_prefix) {
3807                struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
3808                line_prefix = buf->buf;
3809        }
3810
3811        switch(p->status) {
3812        case DIFF_STATUS_DELETED:
3813                fputs(line_prefix, file);
3814                show_file_mode_name(file, "delete", p->one);
3815                break;
3816        case DIFF_STATUS_ADDED:
3817                fputs(line_prefix, file);
3818                show_file_mode_name(file, "create", p->two);
3819                break;
3820        case DIFF_STATUS_COPIED:
3821                fputs(line_prefix, file);
3822                show_rename_copy(file, "copy", p, line_prefix);
3823                break;
3824        case DIFF_STATUS_RENAMED:
3825                fputs(line_prefix, file);
3826                show_rename_copy(file, "rename", p, line_prefix);
3827                break;
3828        default:
3829                if (p->score) {
3830                        fprintf(file, "%s rewrite ", line_prefix);
3831                        write_name_quoted(p->two->path, file, ' ');
3832                        fprintf(file, "(%d%%)\n", similarity_index(p));
3833                }
3834                show_mode_change(file, p, !p->score, line_prefix);
3835                break;
3836        }
3837}
3838
3839struct patch_id_t {
3840        git_SHA_CTX *ctx;
3841        int patchlen;
3842};
3843
3844static int remove_space(char *line, int len)
3845{
3846        int i;
3847        char *dst = line;
3848        unsigned char c;
3849
3850        for (i = 0; i < len; i++)
3851                if (!isspace((c = line[i])))
3852                        *dst++ = c;
3853
3854        return dst - line;
3855}
3856
3857static void patch_id_consume(void *priv, char *line, unsigned long len)
3858{
3859        struct patch_id_t *data = priv;
3860        int new_len;
3861
3862        /* Ignore line numbers when computing the SHA1 of the patch */
3863        if (!prefixcmp(line, "@@ -"))
3864                return;
3865
3866        new_len = remove_space(line, len);
3867
3868        git_SHA1_Update(data->ctx, line, new_len);
3869        data->patchlen += new_len;
3870}
3871
3872/* returns 0 upon success, and writes result into sha1 */
3873static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
3874{
3875        struct diff_queue_struct *q = &diff_queued_diff;
3876        int i;
3877        git_SHA_CTX ctx;
3878        struct patch_id_t data;
3879        char buffer[PATH_MAX * 4 + 20];
3880
3881        git_SHA1_Init(&ctx);
3882        memset(&data, 0, sizeof(struct patch_id_t));
3883        data.ctx = &ctx;
3884
3885        for (i = 0; i < q->nr; i++) {
3886                xpparam_t xpp;
3887                xdemitconf_t xecfg;
3888                mmfile_t mf1, mf2;
3889                struct diff_filepair *p = q->queue[i];
3890                int len1, len2;
3891
3892                memset(&xpp, 0, sizeof(xpp));
3893                memset(&xecfg, 0, sizeof(xecfg));
3894                if (p->status == 0)
3895                        return error("internal diff status error");
3896                if (p->status == DIFF_STATUS_UNKNOWN)
3897                        continue;
3898                if (diff_unmodified_pair(p))
3899                        continue;
3900                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3901                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3902                        continue;
3903                if (DIFF_PAIR_UNMERGED(p))
3904                        continue;
3905
3906                diff_fill_sha1_info(p->one);
3907                diff_fill_sha1_info(p->two);
3908                if (fill_mmfile(&mf1, p->one) < 0 ||
3909                                fill_mmfile(&mf2, p->two) < 0)
3910                        return error("unable to read files to diff");
3911
3912                len1 = remove_space(p->one->path, strlen(p->one->path));
3913                len2 = remove_space(p->two->path, strlen(p->two->path));
3914                if (p->one->mode == 0)
3915                        len1 = snprintf(buffer, sizeof(buffer),
3916                                        "diff--gita/%.*sb/%.*s"
3917                                        "newfilemode%06o"
3918                                        "---/dev/null"
3919                                        "+++b/%.*s",
3920                                        len1, p->one->path,
3921                                        len2, p->two->path,
3922                                        p->two->mode,
3923                                        len2, p->two->path);
3924                else if (p->two->mode == 0)
3925                        len1 = snprintf(buffer, sizeof(buffer),
3926                                        "diff--gita/%.*sb/%.*s"
3927                                        "deletedfilemode%06o"
3928                                        "---a/%.*s"
3929                                        "+++/dev/null",
3930                                        len1, p->one->path,
3931                                        len2, p->two->path,
3932                                        p->one->mode,
3933                                        len1, p->one->path);
3934                else
3935                        len1 = snprintf(buffer, sizeof(buffer),
3936                                        "diff--gita/%.*sb/%.*s"
3937                                        "---a/%.*s"
3938                                        "+++b/%.*s",
3939                                        len1, p->one->path,
3940                                        len2, p->two->path,
3941                                        len1, p->one->path,
3942                                        len2, p->two->path);
3943                git_SHA1_Update(&ctx, buffer, len1);
3944
3945                if (diff_filespec_is_binary(p->one) ||
3946                    diff_filespec_is_binary(p->two)) {
3947                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
3948                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
3949                        continue;
3950                }
3951
3952                xpp.flags = 0;
3953                xecfg.ctxlen = 3;
3954                xecfg.flags = 0;
3955                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
3956                              &xpp, &xecfg);
3957        }
3958
3959        git_SHA1_Final(sha1, &ctx);
3960        return 0;
3961}
3962
3963int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3964{
3965        struct diff_queue_struct *q = &diff_queued_diff;
3966        int i;
3967        int result = diff_get_patch_id(options, sha1);
3968
3969        for (i = 0; i < q->nr; i++)
3970                diff_free_filepair(q->queue[i]);
3971
3972        free(q->queue);
3973        DIFF_QUEUE_CLEAR(q);
3974
3975        return result;
3976}
3977
3978static int is_summary_empty(const struct diff_queue_struct *q)
3979{
3980        int i;
3981
3982        for (i = 0; i < q->nr; i++) {
3983                const struct diff_filepair *p = q->queue[i];
3984
3985                switch (p->status) {
3986                case DIFF_STATUS_DELETED:
3987                case DIFF_STATUS_ADDED:
3988                case DIFF_STATUS_COPIED:
3989                case DIFF_STATUS_RENAMED:
3990                        return 0;
3991                default:
3992                        if (p->score)
3993                                return 0;
3994                        if (p->one->mode && p->two->mode &&
3995                            p->one->mode != p->two->mode)
3996                                return 0;
3997                        break;
3998                }
3999        }
4000        return 1;
4001}
4002
4003static const char rename_limit_warning[] =
4004"inexact rename detection was skipped due to too many files.";
4005
4006static const char degrade_cc_to_c_warning[] =
4007"only found copies from modified paths due to too many files.";
4008
4009static const char rename_limit_advice[] =
4010"you may want to set your %s variable to at least "
4011"%d and retry the command.";
4012
4013void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4014{
4015        if (degraded_cc)
4016                warning(degrade_cc_to_c_warning);
4017        else if (needed)
4018                warning(rename_limit_warning);
4019        else
4020                return;
4021        if (0 < needed && needed < 32767)
4022                warning(rename_limit_advice, varname, needed);
4023}
4024
4025void diff_flush(struct diff_options *options)
4026{
4027        struct diff_queue_struct *q = &diff_queued_diff;
4028        int i, output_format = options->output_format;
4029        int separator = 0;
4030
4031        /*
4032         * Order: raw, stat, summary, patch
4033         * or:    name/name-status/checkdiff (other bits clear)
4034         */
4035        if (!q->nr)
4036                goto free_queue;
4037
4038        if (output_format & (DIFF_FORMAT_RAW |
4039                             DIFF_FORMAT_NAME |
4040                             DIFF_FORMAT_NAME_STATUS |
4041                             DIFF_FORMAT_CHECKDIFF)) {
4042                for (i = 0; i < q->nr; i++) {
4043                        struct diff_filepair *p = q->queue[i];
4044                        if (check_pair_status(p))
4045                                flush_one_pair(p, options);
4046                }
4047                separator++;
4048        }
4049
4050        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
4051                struct diffstat_t diffstat;
4052
4053                memset(&diffstat, 0, sizeof(struct diffstat_t));
4054                for (i = 0; i < q->nr; i++) {
4055                        struct diff_filepair *p = q->queue[i];
4056                        if (check_pair_status(p))
4057                                diff_flush_stat(p, options, &diffstat);
4058                }
4059                if (output_format & DIFF_FORMAT_NUMSTAT)
4060                        show_numstat(&diffstat, options);
4061                if (output_format & DIFF_FORMAT_DIFFSTAT)
4062                        show_stats(&diffstat, options);
4063                if (output_format & DIFF_FORMAT_SHORTSTAT)
4064                        show_shortstats(&diffstat, options);
4065                free_diffstat_info(&diffstat);
4066                separator++;
4067        }
4068        if (output_format & DIFF_FORMAT_DIRSTAT)
4069                show_dirstat(options);
4070
4071        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4072                for (i = 0; i < q->nr; i++) {
4073                        diff_summary(options, q->queue[i]);
4074                }
4075                separator++;
4076        }
4077
4078        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4079            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4080            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4081                /*
4082                 * run diff_flush_patch for the exit status. setting
4083                 * options->file to /dev/null should be safe, becaue we
4084                 * aren't supposed to produce any output anyway.
4085                 */
4086                if (options->close_file)
4087                        fclose(options->file);
4088                options->file = fopen("/dev/null", "w");
4089                if (!options->file)
4090                        die_errno("Could not open /dev/null");
4091                options->close_file = 1;
4092                for (i = 0; i < q->nr; i++) {
4093                        struct diff_filepair *p = q->queue[i];
4094                        if (check_pair_status(p))
4095                                diff_flush_patch(p, options);
4096                        if (options->found_changes)
4097                                break;
4098                }
4099        }
4100
4101        if (output_format & DIFF_FORMAT_PATCH) {
4102                if (separator) {
4103                        putc(options->line_termination, options->file);
4104                        if (options->stat_sep) {
4105                                /* attach patch instead of inline */
4106                                fputs(options->stat_sep, options->file);
4107                        }
4108                }
4109
4110                for (i = 0; i < q->nr; i++) {
4111                        struct diff_filepair *p = q->queue[i];
4112                        if (check_pair_status(p))
4113                                diff_flush_patch(p, options);
4114                }
4115        }
4116
4117        if (output_format & DIFF_FORMAT_CALLBACK)
4118                options->format_callback(q, options, options->format_callback_data);
4119
4120        for (i = 0; i < q->nr; i++)
4121                diff_free_filepair(q->queue[i]);
4122free_queue:
4123        free(q->queue);
4124        DIFF_QUEUE_CLEAR(q);
4125        if (options->close_file)
4126                fclose(options->file);
4127
4128        /*
4129         * Report the content-level differences with HAS_CHANGES;
4130         * diff_addremove/diff_change does not set the bit when
4131         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4132         */
4133        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4134                if (options->found_changes)
4135                        DIFF_OPT_SET(options, HAS_CHANGES);
4136                else
4137                        DIFF_OPT_CLR(options, HAS_CHANGES);
4138        }
4139}
4140
4141static void diffcore_apply_filter(const char *filter)
4142{
4143        int i;
4144        struct diff_queue_struct *q = &diff_queued_diff;
4145        struct diff_queue_struct outq;
4146        DIFF_QUEUE_CLEAR(&outq);
4147
4148        if (!filter)
4149                return;
4150
4151        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4152                int found;
4153                for (i = found = 0; !found && i < q->nr; i++) {
4154                        struct diff_filepair *p = q->queue[i];
4155                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4156                             ((p->score &&
4157                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4158                              (!p->score &&
4159                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4160                            ((p->status != DIFF_STATUS_MODIFIED) &&
4161                             strchr(filter, p->status)))
4162                                found++;
4163                }
4164                if (found)
4165                        return;
4166
4167                /* otherwise we will clear the whole queue
4168                 * by copying the empty outq at the end of this
4169                 * function, but first clear the current entries
4170                 * in the queue.
4171                 */
4172                for (i = 0; i < q->nr; i++)
4173                        diff_free_filepair(q->queue[i]);
4174        }
4175        else {
4176                /* Only the matching ones */
4177                for (i = 0; i < q->nr; i++) {
4178                        struct diff_filepair *p = q->queue[i];
4179
4180                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4181                             ((p->score &&
4182                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4183                              (!p->score &&
4184                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4185                            ((p->status != DIFF_STATUS_MODIFIED) &&
4186                             strchr(filter, p->status)))
4187                                diff_q(&outq, p);
4188                        else
4189                                diff_free_filepair(p);
4190                }
4191        }
4192        free(q->queue);
4193        *q = outq;
4194}
4195
4196/* Check whether two filespecs with the same mode and size are identical */
4197static int diff_filespec_is_identical(struct diff_filespec *one,
4198                                      struct diff_filespec *two)
4199{
4200        if (S_ISGITLINK(one->mode))
4201                return 0;
4202        if (diff_populate_filespec(one, 0))
4203                return 0;
4204        if (diff_populate_filespec(two, 0))
4205                return 0;
4206        return !memcmp(one->data, two->data, one->size);
4207}
4208
4209static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4210{
4211        int i;
4212        struct diff_queue_struct *q = &diff_queued_diff;
4213        struct diff_queue_struct outq;
4214        DIFF_QUEUE_CLEAR(&outq);
4215
4216        for (i = 0; i < q->nr; i++) {
4217                struct diff_filepair *p = q->queue[i];
4218
4219                /*
4220                 * 1. Entries that come from stat info dirtiness
4221                 *    always have both sides (iow, not create/delete),
4222                 *    one side of the object name is unknown, with
4223                 *    the same mode and size.  Keep the ones that
4224                 *    do not match these criteria.  They have real
4225                 *    differences.
4226                 *
4227                 * 2. At this point, the file is known to be modified,
4228                 *    with the same mode and size, and the object
4229                 *    name of one side is unknown.  Need to inspect
4230                 *    the identical contents.
4231                 */
4232                if (!DIFF_FILE_VALID(p->one) || /* (1) */
4233                    !DIFF_FILE_VALID(p->two) ||
4234                    (p->one->sha1_valid && p->two->sha1_valid) ||
4235                    (p->one->mode != p->two->mode) ||
4236                    diff_populate_filespec(p->one, 1) ||
4237                    diff_populate_filespec(p->two, 1) ||
4238                    (p->one->size != p->two->size) ||
4239                    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4240                        diff_q(&outq, p);
4241                else {
4242                        /*
4243                         * The caller can subtract 1 from skip_stat_unmatch
4244                         * to determine how many paths were dirty only
4245                         * due to stat info mismatch.
4246                         */
4247                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4248                                diffopt->skip_stat_unmatch++;
4249                        diff_free_filepair(p);
4250                }
4251        }
4252        free(q->queue);
4253        *q = outq;
4254}
4255
4256static int diffnamecmp(const void *a_, const void *b_)
4257{
4258        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4259        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4260        const char *name_a, *name_b;
4261
4262        name_a = a->one ? a->one->path : a->two->path;
4263        name_b = b->one ? b->one->path : b->two->path;
4264        return strcmp(name_a, name_b);
4265}
4266
4267void diffcore_fix_diff_index(struct diff_options *options)
4268{
4269        struct diff_queue_struct *q = &diff_queued_diff;
4270        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4271}
4272
4273void diffcore_std(struct diff_options *options)
4274{
4275        if (options->skip_stat_unmatch)
4276                diffcore_skip_stat_unmatch(options);
4277        if (!options->found_follow) {
4278                /* See try_to_follow_renames() in tree-diff.c */
4279                if (options->break_opt != -1)
4280                        diffcore_break(options->break_opt);
4281                if (options->detect_rename)
4282                        diffcore_rename(options);
4283                if (options->break_opt != -1)
4284                        diffcore_merge_broken();
4285        }
4286        if (options->pickaxe)
4287                diffcore_pickaxe(options);
4288        if (options->orderfile)
4289                diffcore_order(options->orderfile);
4290        if (!options->found_follow)
4291                /* See try_to_follow_renames() in tree-diff.c */
4292                diff_resolve_rename_copy();
4293        diffcore_apply_filter(options->filter);
4294
4295        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4296                DIFF_OPT_SET(options, HAS_CHANGES);
4297        else
4298                DIFF_OPT_CLR(options, HAS_CHANGES);
4299
4300        options->found_follow = 0;
4301}
4302
4303int diff_result_code(struct diff_options *opt, int status)
4304{
4305        int result = 0;
4306
4307        diff_warn_rename_limit("diff.renamelimit",
4308                               opt->needed_rename_limit,
4309                               opt->degraded_cc_to_c);
4310        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4311            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4312                return status;
4313        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4314            DIFF_OPT_TST(opt, HAS_CHANGES))
4315                result |= 01;
4316        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4317            DIFF_OPT_TST(opt, CHECK_FAILED))
4318                result |= 02;
4319        return result;
4320}
4321
4322/*
4323 * Shall changes to this submodule be ignored?
4324 *
4325 * Submodule changes can be configured to be ignored separately for each path,
4326 * but that configuration can be overridden from the command line.
4327 */
4328static int is_submodule_ignored(const char *path, struct diff_options *options)
4329{
4330        int ignored = 0;
4331        unsigned orig_flags = options->flags;
4332        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4333                set_diffopt_flags_from_submodule_config(options, path);
4334        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4335                ignored = 1;
4336        options->flags = orig_flags;
4337        return ignored;
4338}
4339
4340void diff_addremove(struct diff_options *options,
4341                    int addremove, unsigned mode,
4342                    const unsigned char *sha1,
4343                    const char *concatpath, unsigned dirty_submodule)
4344{
4345        struct diff_filespec *one, *two;
4346
4347        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4348                return;
4349
4350        /* This may look odd, but it is a preparation for
4351         * feeding "there are unchanged files which should
4352         * not produce diffs, but when you are doing copy
4353         * detection you would need them, so here they are"
4354         * entries to the diff-core.  They will be prefixed
4355         * with something like '=' or '*' (I haven't decided
4356         * which but should not make any difference).
4357         * Feeding the same new and old to diff_change()
4358         * also has the same effect.
4359         * Before the final output happens, they are pruned after
4360         * merged into rename/copy pairs as appropriate.
4361         */
4362        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4363                addremove = (addremove == '+' ? '-' :
4364                             addremove == '-' ? '+' : addremove);
4365
4366        if (options->prefix &&
4367            strncmp(concatpath, options->prefix, options->prefix_length))
4368                return;
4369
4370        one = alloc_filespec(concatpath);
4371        two = alloc_filespec(concatpath);
4372
4373        if (addremove != '+')
4374                fill_filespec(one, sha1, mode);
4375        if (addremove != '-') {
4376                fill_filespec(two, sha1, mode);
4377                two->dirty_submodule = dirty_submodule;
4378        }
4379
4380        diff_queue(&diff_queued_diff, one, two);
4381        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4382                DIFF_OPT_SET(options, HAS_CHANGES);
4383}
4384
4385void diff_change(struct diff_options *options,
4386                 unsigned old_mode, unsigned new_mode,
4387                 const unsigned char *old_sha1,
4388                 const unsigned char *new_sha1,
4389                 const char *concatpath,
4390                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4391{
4392        struct diff_filespec *one, *two;
4393
4394        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4395            is_submodule_ignored(concatpath, options))
4396                return;
4397
4398        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4399                unsigned tmp;
4400                const unsigned char *tmp_c;
4401                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4402                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4403                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4404                        new_dirty_submodule = tmp;
4405        }
4406
4407        if (options->prefix &&
4408            strncmp(concatpath, options->prefix, options->prefix_length))
4409                return;
4410
4411        one = alloc_filespec(concatpath);
4412        two = alloc_filespec(concatpath);
4413        fill_filespec(one, old_sha1, old_mode);
4414        fill_filespec(two, new_sha1, new_mode);
4415        one->dirty_submodule = old_dirty_submodule;
4416        two->dirty_submodule = new_dirty_submodule;
4417
4418        diff_queue(&diff_queued_diff, one, two);
4419        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4420                DIFF_OPT_SET(options, HAS_CHANGES);
4421}
4422
4423void diff_unmerge(struct diff_options *options,
4424                  const char *path,
4425                  unsigned mode, const unsigned char *sha1)
4426{
4427        struct diff_filespec *one, *two;
4428
4429        if (options->prefix &&
4430            strncmp(path, options->prefix, options->prefix_length))
4431                return;
4432
4433        one = alloc_filespec(path);
4434        two = alloc_filespec(path);
4435        fill_filespec(one, sha1, mode);
4436        diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
4437}
4438
4439static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4440                size_t *outsize)
4441{
4442        struct diff_tempfile *temp;
4443        const char *argv[3];
4444        const char **arg = argv;
4445        struct child_process child;
4446        struct strbuf buf = STRBUF_INIT;
4447        int err = 0;
4448
4449        temp = prepare_temp_file(spec->path, spec);
4450        *arg++ = pgm;
4451        *arg++ = temp->name;
4452        *arg = NULL;
4453
4454        memset(&child, 0, sizeof(child));
4455        child.use_shell = 1;
4456        child.argv = argv;
4457        child.out = -1;
4458        if (start_command(&child)) {
4459                remove_tempfile();
4460                return NULL;
4461        }
4462
4463        if (strbuf_read(&buf, child.out, 0) < 0)
4464                err = error("error reading from textconv command '%s'", pgm);
4465        close(child.out);
4466
4467        if (finish_command(&child) || err) {
4468                strbuf_release(&buf);
4469                remove_tempfile();
4470                return NULL;
4471        }
4472        remove_tempfile();
4473
4474        return strbuf_detach(&buf, outsize);
4475}
4476
4477size_t fill_textconv(struct userdiff_driver *driver,
4478                     struct diff_filespec *df,
4479                     char **outbuf)
4480{
4481        size_t size;
4482
4483        if (!driver || !driver->textconv) {
4484                if (!DIFF_FILE_VALID(df)) {
4485                        *outbuf = "";
4486                        return 0;
4487                }
4488                if (diff_populate_filespec(df, 0))
4489                        die("unable to read files to diff");
4490                *outbuf = df->data;
4491                return df->size;
4492        }
4493
4494        if (driver->textconv_cache && df->sha1_valid) {
4495                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4496                                          &size);
4497                if (*outbuf)
4498                        return size;
4499        }
4500
4501        *outbuf = run_textconv(driver->textconv, df, &size);
4502        if (!*outbuf)
4503                die("unable to read files to diff");
4504
4505        if (driver->textconv_cache && df->sha1_valid) {
4506                /* ignore errors, as we might be in a readonly repository */
4507                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4508                                size);
4509                /*
4510                 * we could save up changes and flush them all at the end,
4511                 * but we would need an extra call after all diffing is done.
4512                 * Since generating a cache entry is the slow path anyway,
4513                 * this extra overhead probably isn't a big deal.
4514                 */
4515                notes_cache_write(driver->textconv_cache);
4516        }
4517
4518        return size;
4519}