diff.con commit shallow: remove unused #include "sigchain.h" (4b7c50a)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "tempfile.h"
   6#include "quote.h"
   7#include "diff.h"
   8#include "diffcore.h"
   9#include "delta.h"
  10#include "xdiff-interface.h"
  11#include "color.h"
  12#include "attr.h"
  13#include "run-command.h"
  14#include "utf8.h"
  15#include "userdiff.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18#include "string-list.h"
  19#include "argv-array.h"
  20
  21#ifdef NO_FAST_WORKING_DIRECTORY
  22#define FAST_WORKING_DIRECTORY 0
  23#else
  24#define FAST_WORKING_DIRECTORY 1
  25#endif
  26
  27static int diff_detect_rename_default;
  28static int diff_rename_limit_default = 400;
  29static int diff_suppress_blank_empty;
  30static int diff_use_color_default = -1;
  31static int diff_context_default = 3;
  32static const char *diff_word_regex_cfg;
  33static const char *external_diff_cmd_cfg;
  34static const char *diff_order_file_cfg;
  35int diff_auto_refresh_index = 1;
  36static int diff_mnemonic_prefix;
  37static int diff_no_prefix;
  38static int diff_stat_graph_width;
  39static int diff_dirstat_permille_default = 30;
  40static struct diff_options default_diff_options;
  41static long diff_algorithm;
  42
  43static char diff_colors[][COLOR_MAXLEN] = {
  44        GIT_COLOR_RESET,
  45        GIT_COLOR_NORMAL,       /* PLAIN */
  46        GIT_COLOR_BOLD,         /* METAINFO */
  47        GIT_COLOR_CYAN,         /* FRAGINFO */
  48        GIT_COLOR_RED,          /* OLD */
  49        GIT_COLOR_GREEN,        /* NEW */
  50        GIT_COLOR_YELLOW,       /* COMMIT */
  51        GIT_COLOR_BG_RED,       /* WHITESPACE */
  52        GIT_COLOR_NORMAL,       /* FUNCINFO */
  53};
  54
  55static int parse_diff_color_slot(const char *var)
  56{
  57        if (!strcasecmp(var, "plain"))
  58                return DIFF_PLAIN;
  59        if (!strcasecmp(var, "meta"))
  60                return DIFF_METAINFO;
  61        if (!strcasecmp(var, "frag"))
  62                return DIFF_FRAGINFO;
  63        if (!strcasecmp(var, "old"))
  64                return DIFF_FILE_OLD;
  65        if (!strcasecmp(var, "new"))
  66                return DIFF_FILE_NEW;
  67        if (!strcasecmp(var, "commit"))
  68                return DIFF_COMMIT;
  69        if (!strcasecmp(var, "whitespace"))
  70                return DIFF_WHITESPACE;
  71        if (!strcasecmp(var, "func"))
  72                return DIFF_FUNCINFO;
  73        return -1;
  74}
  75
  76static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  77                                struct strbuf *errmsg)
  78{
  79        char *params_copy = xstrdup(params_string);
  80        struct string_list params = STRING_LIST_INIT_NODUP;
  81        int ret = 0;
  82        int i;
  83
  84        if (*params_copy)
  85                string_list_split_in_place(&params, params_copy, ',', -1);
  86        for (i = 0; i < params.nr; i++) {
  87                const char *p = params.items[i].string;
  88                if (!strcmp(p, "changes")) {
  89                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  90                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  91                } else if (!strcmp(p, "lines")) {
  92                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  93                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  94                } else if (!strcmp(p, "files")) {
  95                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  96                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  97                } else if (!strcmp(p, "noncumulative")) {
  98                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  99                } else if (!strcmp(p, "cumulative")) {
 100                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 101                } else if (isdigit(*p)) {
 102                        char *end;
 103                        int permille = strtoul(p, &end, 10) * 10;
 104                        if (*end == '.' && isdigit(*++end)) {
 105                                /* only use first digit */
 106                                permille += *end - '0';
 107                                /* .. and ignore any further digits */
 108                                while (isdigit(*++end))
 109                                        ; /* nothing */
 110                        }
 111                        if (!*end)
 112                                options->dirstat_permille = permille;
 113                        else {
 114                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 115                                            p);
 116                                ret++;
 117                        }
 118                } else {
 119                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 120                        ret++;
 121                }
 122
 123        }
 124        string_list_clear(&params, 0);
 125        free(params_copy);
 126        return ret;
 127}
 128
 129static int parse_submodule_params(struct diff_options *options, const char *value)
 130{
 131        if (!strcmp(value, "log"))
 132                DIFF_OPT_SET(options, SUBMODULE_LOG);
 133        else if (!strcmp(value, "short"))
 134                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 135        else
 136                return -1;
 137        return 0;
 138}
 139
 140static int git_config_rename(const char *var, const char *value)
 141{
 142        if (!value)
 143                return DIFF_DETECT_RENAME;
 144        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 145                return  DIFF_DETECT_COPY;
 146        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 147}
 148
 149long parse_algorithm_value(const char *value)
 150{
 151        if (!value)
 152                return -1;
 153        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 154                return 0;
 155        else if (!strcasecmp(value, "minimal"))
 156                return XDF_NEED_MINIMAL;
 157        else if (!strcasecmp(value, "patience"))
 158                return XDF_PATIENCE_DIFF;
 159        else if (!strcasecmp(value, "histogram"))
 160                return XDF_HISTOGRAM_DIFF;
 161        return -1;
 162}
 163
 164/*
 165 * These are to give UI layer defaults.
 166 * The core-level commands such as git-diff-files should
 167 * never be affected by the setting of diff.renames
 168 * the user happens to have in the configuration file.
 169 */
 170int git_diff_ui_config(const char *var, const char *value, void *cb)
 171{
 172        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 173                diff_use_color_default = git_config_colorbool(var, value);
 174                return 0;
 175        }
 176        if (!strcmp(var, "diff.context")) {
 177                diff_context_default = git_config_int(var, value);
 178                if (diff_context_default < 0)
 179                        return -1;
 180                return 0;
 181        }
 182        if (!strcmp(var, "diff.renames")) {
 183                diff_detect_rename_default = git_config_rename(var, value);
 184                return 0;
 185        }
 186        if (!strcmp(var, "diff.autorefreshindex")) {
 187                diff_auto_refresh_index = git_config_bool(var, value);
 188                return 0;
 189        }
 190        if (!strcmp(var, "diff.mnemonicprefix")) {
 191                diff_mnemonic_prefix = git_config_bool(var, value);
 192                return 0;
 193        }
 194        if (!strcmp(var, "diff.noprefix")) {
 195                diff_no_prefix = git_config_bool(var, value);
 196                return 0;
 197        }
 198        if (!strcmp(var, "diff.statgraphwidth")) {
 199                diff_stat_graph_width = git_config_int(var, value);
 200                return 0;
 201        }
 202        if (!strcmp(var, "diff.external"))
 203                return git_config_string(&external_diff_cmd_cfg, var, value);
 204        if (!strcmp(var, "diff.wordregex"))
 205                return git_config_string(&diff_word_regex_cfg, var, value);
 206        if (!strcmp(var, "diff.orderfile"))
 207                return git_config_pathname(&diff_order_file_cfg, var, value);
 208
 209        if (!strcmp(var, "diff.ignoresubmodules"))
 210                handle_ignore_submodules_arg(&default_diff_options, value);
 211
 212        if (!strcmp(var, "diff.submodule")) {
 213                if (parse_submodule_params(&default_diff_options, value))
 214                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 215                                value);
 216                return 0;
 217        }
 218
 219        if (!strcmp(var, "diff.algorithm")) {
 220                diff_algorithm = parse_algorithm_value(value);
 221                if (diff_algorithm < 0)
 222                        return -1;
 223                return 0;
 224        }
 225
 226        if (git_color_config(var, value, cb) < 0)
 227                return -1;
 228
 229        return git_diff_basic_config(var, value, cb);
 230}
 231
 232int git_diff_basic_config(const char *var, const char *value, void *cb)
 233{
 234        const char *name;
 235
 236        if (!strcmp(var, "diff.renamelimit")) {
 237                diff_rename_limit_default = git_config_int(var, value);
 238                return 0;
 239        }
 240
 241        if (userdiff_config(var, value) < 0)
 242                return -1;
 243
 244        if (skip_prefix(var, "diff.color.", &name) ||
 245            skip_prefix(var, "color.diff.", &name)) {
 246                int slot = parse_diff_color_slot(name);
 247                if (slot < 0)
 248                        return 0;
 249                if (!value)
 250                        return config_error_nonbool(var);
 251                return color_parse(value, diff_colors[slot]);
 252        }
 253
 254        /* like GNU diff's --suppress-blank-empty option  */
 255        if (!strcmp(var, "diff.suppressblankempty") ||
 256                        /* for backwards compatibility */
 257                        !strcmp(var, "diff.suppress-blank-empty")) {
 258                diff_suppress_blank_empty = git_config_bool(var, value);
 259                return 0;
 260        }
 261
 262        if (!strcmp(var, "diff.dirstat")) {
 263                struct strbuf errmsg = STRBUF_INIT;
 264                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 265                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 266                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 267                                errmsg.buf);
 268                strbuf_release(&errmsg);
 269                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 270                return 0;
 271        }
 272
 273        if (starts_with(var, "submodule."))
 274                return parse_submodule_config_option(var, value);
 275
 276        return git_default_config(var, value, cb);
 277}
 278
 279static char *quote_two(const char *one, const char *two)
 280{
 281        int need_one = quote_c_style(one, NULL, NULL, 1);
 282        int need_two = quote_c_style(two, NULL, NULL, 1);
 283        struct strbuf res = STRBUF_INIT;
 284
 285        if (need_one + need_two) {
 286                strbuf_addch(&res, '"');
 287                quote_c_style(one, &res, NULL, 1);
 288                quote_c_style(two, &res, NULL, 1);
 289                strbuf_addch(&res, '"');
 290        } else {
 291                strbuf_addstr(&res, one);
 292                strbuf_addstr(&res, two);
 293        }
 294        return strbuf_detach(&res, NULL);
 295}
 296
 297static const char *external_diff(void)
 298{
 299        static const char *external_diff_cmd = NULL;
 300        static int done_preparing = 0;
 301
 302        if (done_preparing)
 303                return external_diff_cmd;
 304        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 305        if (!external_diff_cmd)
 306                external_diff_cmd = external_diff_cmd_cfg;
 307        done_preparing = 1;
 308        return external_diff_cmd;
 309}
 310
 311/*
 312 * Keep track of files used for diffing. Sometimes such an entry
 313 * refers to a temporary file, sometimes to an existing file, and
 314 * sometimes to "/dev/null".
 315 */
 316static struct diff_tempfile {
 317        /*
 318         * filename external diff should read from, or NULL if this
 319         * entry is currently not in use:
 320         */
 321        const char *name;
 322
 323        char hex[41];
 324        char mode[10];
 325
 326        /*
 327         * If this diff_tempfile instance refers to a temporary file,
 328         * this tempfile object is used to manage its lifetime.
 329         */
 330        struct tempfile tempfile;
 331} diff_temp[2];
 332
 333typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 334
 335struct emit_callback {
 336        int color_diff;
 337        unsigned ws_rule;
 338        int blank_at_eof_in_preimage;
 339        int blank_at_eof_in_postimage;
 340        int lno_in_preimage;
 341        int lno_in_postimage;
 342        sane_truncate_fn truncate;
 343        const char **label_path;
 344        struct diff_words_data *diff_words;
 345        struct diff_options *opt;
 346        int *found_changesp;
 347        struct strbuf *header;
 348};
 349
 350static int count_lines(const char *data, int size)
 351{
 352        int count, ch, completely_empty = 1, nl_just_seen = 0;
 353        count = 0;
 354        while (0 < size--) {
 355                ch = *data++;
 356                if (ch == '\n') {
 357                        count++;
 358                        nl_just_seen = 1;
 359                        completely_empty = 0;
 360                }
 361                else {
 362                        nl_just_seen = 0;
 363                        completely_empty = 0;
 364                }
 365        }
 366        if (completely_empty)
 367                return 0;
 368        if (!nl_just_seen)
 369                count++; /* no trailing newline */
 370        return count;
 371}
 372
 373static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 374{
 375        if (!DIFF_FILE_VALID(one)) {
 376                mf->ptr = (char *)""; /* does not matter */
 377                mf->size = 0;
 378                return 0;
 379        }
 380        else if (diff_populate_filespec(one, 0))
 381                return -1;
 382
 383        mf->ptr = one->data;
 384        mf->size = one->size;
 385        return 0;
 386}
 387
 388/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 389static unsigned long diff_filespec_size(struct diff_filespec *one)
 390{
 391        if (!DIFF_FILE_VALID(one))
 392                return 0;
 393        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 394        return one->size;
 395}
 396
 397static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 398{
 399        char *ptr = mf->ptr;
 400        long size = mf->size;
 401        int cnt = 0;
 402
 403        if (!size)
 404                return cnt;
 405        ptr += size - 1; /* pointing at the very end */
 406        if (*ptr != '\n')
 407                ; /* incomplete line */
 408        else
 409                ptr--; /* skip the last LF */
 410        while (mf->ptr < ptr) {
 411                char *prev_eol;
 412                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 413                        if (*prev_eol == '\n')
 414                                break;
 415                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 416                        break;
 417                cnt++;
 418                ptr = prev_eol - 1;
 419        }
 420        return cnt;
 421}
 422
 423static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 424                               struct emit_callback *ecbdata)
 425{
 426        int l1, l2, at;
 427        unsigned ws_rule = ecbdata->ws_rule;
 428        l1 = count_trailing_blank(mf1, ws_rule);
 429        l2 = count_trailing_blank(mf2, ws_rule);
 430        if (l2 <= l1) {
 431                ecbdata->blank_at_eof_in_preimage = 0;
 432                ecbdata->blank_at_eof_in_postimage = 0;
 433                return;
 434        }
 435        at = count_lines(mf1->ptr, mf1->size);
 436        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 437
 438        at = count_lines(mf2->ptr, mf2->size);
 439        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 440}
 441
 442static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 443                        int first, const char *line, int len)
 444{
 445        int has_trailing_newline, has_trailing_carriage_return;
 446        int nofirst;
 447        FILE *file = o->file;
 448
 449        fputs(diff_line_prefix(o), file);
 450
 451        if (len == 0) {
 452                has_trailing_newline = (first == '\n');
 453                has_trailing_carriage_return = (!has_trailing_newline &&
 454                                                (first == '\r'));
 455                nofirst = has_trailing_newline || has_trailing_carriage_return;
 456        } else {
 457                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 458                if (has_trailing_newline)
 459                        len--;
 460                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 461                if (has_trailing_carriage_return)
 462                        len--;
 463                nofirst = 0;
 464        }
 465
 466        if (len || !nofirst) {
 467                fputs(set, file);
 468                if (!nofirst)
 469                        fputc(first, file);
 470                fwrite(line, len, 1, file);
 471                fputs(reset, file);
 472        }
 473        if (has_trailing_carriage_return)
 474                fputc('\r', file);
 475        if (has_trailing_newline)
 476                fputc('\n', file);
 477}
 478
 479static void emit_line(struct diff_options *o, const char *set, const char *reset,
 480                      const char *line, int len)
 481{
 482        emit_line_0(o, set, reset, line[0], line+1, len-1);
 483}
 484
 485static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 486{
 487        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 488              ecbdata->blank_at_eof_in_preimage &&
 489              ecbdata->blank_at_eof_in_postimage &&
 490              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 491              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 492                return 0;
 493        return ws_blank_line(line, len, ecbdata->ws_rule);
 494}
 495
 496static void emit_add_line(const char *reset,
 497                          struct emit_callback *ecbdata,
 498                          const char *line, int len)
 499{
 500        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 501        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 502
 503        if (!*ws)
 504                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 505        else if (new_blank_line_at_eof(ecbdata, line, len))
 506                /* Blank line at EOF - paint '+' as well */
 507                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 508        else {
 509                /* Emit just the prefix, then the rest. */
 510                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 511                ws_check_emit(line, len, ecbdata->ws_rule,
 512                              ecbdata->opt->file, set, reset, ws);
 513        }
 514}
 515
 516static void emit_hunk_header(struct emit_callback *ecbdata,
 517                             const char *line, int len)
 518{
 519        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 520        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 521        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 522        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 523        static const char atat[2] = { '@', '@' };
 524        const char *cp, *ep;
 525        struct strbuf msgbuf = STRBUF_INIT;
 526        int org_len = len;
 527        int i = 1;
 528
 529        /*
 530         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 531         * it always is at least 10 bytes long.
 532         */
 533        if (len < 10 ||
 534            memcmp(line, atat, 2) ||
 535            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 536                emit_line(ecbdata->opt, plain, reset, line, len);
 537                return;
 538        }
 539        ep += 2; /* skip over @@ */
 540
 541        /* The hunk header in fraginfo color */
 542        strbuf_addstr(&msgbuf, frag);
 543        strbuf_add(&msgbuf, line, ep - line);
 544        strbuf_addstr(&msgbuf, reset);
 545
 546        /*
 547         * trailing "\r\n"
 548         */
 549        for ( ; i < 3; i++)
 550                if (line[len - i] == '\r' || line[len - i] == '\n')
 551                        len--;
 552
 553        /* blank before the func header */
 554        for (cp = ep; ep - line < len; ep++)
 555                if (*ep != ' ' && *ep != '\t')
 556                        break;
 557        if (ep != cp) {
 558                strbuf_addstr(&msgbuf, plain);
 559                strbuf_add(&msgbuf, cp, ep - cp);
 560                strbuf_addstr(&msgbuf, reset);
 561        }
 562
 563        if (ep < line + len) {
 564                strbuf_addstr(&msgbuf, func);
 565                strbuf_add(&msgbuf, ep, line + len - ep);
 566                strbuf_addstr(&msgbuf, reset);
 567        }
 568
 569        strbuf_add(&msgbuf, line + len, org_len - len);
 570        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 571        strbuf_release(&msgbuf);
 572}
 573
 574static struct diff_tempfile *claim_diff_tempfile(void) {
 575        int i;
 576        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 577                if (!diff_temp[i].name)
 578                        return diff_temp + i;
 579        die("BUG: diff is failing to clean up its tempfiles");
 580}
 581
 582static void remove_tempfile(void)
 583{
 584        int i;
 585        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 586                if (is_tempfile_active(&diff_temp[i].tempfile))
 587                        delete_tempfile(&diff_temp[i].tempfile);
 588                diff_temp[i].name = NULL;
 589        }
 590}
 591
 592static void print_line_count(FILE *file, int count)
 593{
 594        switch (count) {
 595        case 0:
 596                fprintf(file, "0,0");
 597                break;
 598        case 1:
 599                fprintf(file, "1");
 600                break;
 601        default:
 602                fprintf(file, "1,%d", count);
 603                break;
 604        }
 605}
 606
 607static void emit_rewrite_lines(struct emit_callback *ecb,
 608                               int prefix, const char *data, int size)
 609{
 610        const char *endp = NULL;
 611        static const char *nneof = " No newline at end of file\n";
 612        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 613        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 614
 615        while (0 < size) {
 616                int len;
 617
 618                endp = memchr(data, '\n', size);
 619                len = endp ? (endp - data + 1) : size;
 620                if (prefix != '+') {
 621                        ecb->lno_in_preimage++;
 622                        emit_line_0(ecb->opt, old, reset, '-',
 623                                    data, len);
 624                } else {
 625                        ecb->lno_in_postimage++;
 626                        emit_add_line(reset, ecb, data, len);
 627                }
 628                size -= len;
 629                data += len;
 630        }
 631        if (!endp) {
 632                const char *plain = diff_get_color(ecb->color_diff,
 633                                                   DIFF_PLAIN);
 634                putc('\n', ecb->opt->file);
 635                emit_line_0(ecb->opt, plain, reset, '\\',
 636                            nneof, strlen(nneof));
 637        }
 638}
 639
 640static void emit_rewrite_diff(const char *name_a,
 641                              const char *name_b,
 642                              struct diff_filespec *one,
 643                              struct diff_filespec *two,
 644                              struct userdiff_driver *textconv_one,
 645                              struct userdiff_driver *textconv_two,
 646                              struct diff_options *o)
 647{
 648        int lc_a, lc_b;
 649        const char *name_a_tab, *name_b_tab;
 650        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 651        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 652        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 653        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 654        const char *a_prefix, *b_prefix;
 655        char *data_one, *data_two;
 656        size_t size_one, size_two;
 657        struct emit_callback ecbdata;
 658        const char *line_prefix = diff_line_prefix(o);
 659
 660        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 661                a_prefix = o->b_prefix;
 662                b_prefix = o->a_prefix;
 663        } else {
 664                a_prefix = o->a_prefix;
 665                b_prefix = o->b_prefix;
 666        }
 667
 668        name_a += (*name_a == '/');
 669        name_b += (*name_b == '/');
 670        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 671        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 672
 673        strbuf_reset(&a_name);
 674        strbuf_reset(&b_name);
 675        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 676        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 677
 678        size_one = fill_textconv(textconv_one, one, &data_one);
 679        size_two = fill_textconv(textconv_two, two, &data_two);
 680
 681        memset(&ecbdata, 0, sizeof(ecbdata));
 682        ecbdata.color_diff = want_color(o->use_color);
 683        ecbdata.found_changesp = &o->found_changes;
 684        ecbdata.ws_rule = whitespace_rule(name_b);
 685        ecbdata.opt = o;
 686        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 687                mmfile_t mf1, mf2;
 688                mf1.ptr = (char *)data_one;
 689                mf2.ptr = (char *)data_two;
 690                mf1.size = size_one;
 691                mf2.size = size_two;
 692                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 693        }
 694        ecbdata.lno_in_preimage = 1;
 695        ecbdata.lno_in_postimage = 1;
 696
 697        lc_a = count_lines(data_one, size_one);
 698        lc_b = count_lines(data_two, size_two);
 699        fprintf(o->file,
 700                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 701                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 702                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 703                line_prefix, fraginfo);
 704        if (!o->irreversible_delete)
 705                print_line_count(o->file, lc_a);
 706        else
 707                fprintf(o->file, "?,?");
 708        fprintf(o->file, " +");
 709        print_line_count(o->file, lc_b);
 710        fprintf(o->file, " @@%s\n", reset);
 711        if (lc_a && !o->irreversible_delete)
 712                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 713        if (lc_b)
 714                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 715        if (textconv_one)
 716                free((char *)data_one);
 717        if (textconv_two)
 718                free((char *)data_two);
 719}
 720
 721struct diff_words_buffer {
 722        mmfile_t text;
 723        long alloc;
 724        struct diff_words_orig {
 725                const char *begin, *end;
 726        } *orig;
 727        int orig_nr, orig_alloc;
 728};
 729
 730static void diff_words_append(char *line, unsigned long len,
 731                struct diff_words_buffer *buffer)
 732{
 733        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 734        line++;
 735        len--;
 736        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 737        buffer->text.size += len;
 738        buffer->text.ptr[buffer->text.size] = '\0';
 739}
 740
 741struct diff_words_style_elem {
 742        const char *prefix;
 743        const char *suffix;
 744        const char *color; /* NULL; filled in by the setup code if
 745                            * color is enabled */
 746};
 747
 748struct diff_words_style {
 749        enum diff_words_type type;
 750        struct diff_words_style_elem new, old, ctx;
 751        const char *newline;
 752};
 753
 754static struct diff_words_style diff_words_styles[] = {
 755        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 756        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 757        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 758};
 759
 760struct diff_words_data {
 761        struct diff_words_buffer minus, plus;
 762        const char *current_plus;
 763        int last_minus;
 764        struct diff_options *opt;
 765        regex_t *word_regex;
 766        enum diff_words_type type;
 767        struct diff_words_style *style;
 768};
 769
 770static int fn_out_diff_words_write_helper(FILE *fp,
 771                                          struct diff_words_style_elem *st_el,
 772                                          const char *newline,
 773                                          size_t count, const char *buf,
 774                                          const char *line_prefix)
 775{
 776        int print = 0;
 777
 778        while (count) {
 779                char *p = memchr(buf, '\n', count);
 780                if (print)
 781                        fputs(line_prefix, fp);
 782                if (p != buf) {
 783                        if (st_el->color && fputs(st_el->color, fp) < 0)
 784                                return -1;
 785                        if (fputs(st_el->prefix, fp) < 0 ||
 786                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 787                            fputs(st_el->suffix, fp) < 0)
 788                                return -1;
 789                        if (st_el->color && *st_el->color
 790                            && fputs(GIT_COLOR_RESET, fp) < 0)
 791                                return -1;
 792                }
 793                if (!p)
 794                        return 0;
 795                if (fputs(newline, fp) < 0)
 796                        return -1;
 797                count -= p + 1 - buf;
 798                buf = p + 1;
 799                print = 1;
 800        }
 801        return 0;
 802}
 803
 804/*
 805 * '--color-words' algorithm can be described as:
 806 *
 807 *   1. collect a the minus/plus lines of a diff hunk, divided into
 808 *      minus-lines and plus-lines;
 809 *
 810 *   2. break both minus-lines and plus-lines into words and
 811 *      place them into two mmfile_t with one word for each line;
 812 *
 813 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 814 *
 815 * And for the common parts of the both file, we output the plus side text.
 816 * diff_words->current_plus is used to trace the current position of the plus file
 817 * which printed. diff_words->last_minus is used to trace the last minus word
 818 * printed.
 819 *
 820 * For '--graph' to work with '--color-words', we need to output the graph prefix
 821 * on each line of color words output. Generally, there are two conditions on
 822 * which we should output the prefix.
 823 *
 824 *   1. diff_words->last_minus == 0 &&
 825 *      diff_words->current_plus == diff_words->plus.text.ptr
 826 *
 827 *      that is: the plus text must start as a new line, and if there is no minus
 828 *      word printed, a graph prefix must be printed.
 829 *
 830 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 831 *      *(diff_words->current_plus - 1) == '\n'
 832 *
 833 *      that is: a graph prefix must be printed following a '\n'
 834 */
 835static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 836{
 837        if ((diff_words->last_minus == 0 &&
 838                diff_words->current_plus == diff_words->plus.text.ptr) ||
 839                (diff_words->current_plus > diff_words->plus.text.ptr &&
 840                *(diff_words->current_plus - 1) == '\n')) {
 841                return 1;
 842        } else {
 843                return 0;
 844        }
 845}
 846
 847static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 848{
 849        struct diff_words_data *diff_words = priv;
 850        struct diff_words_style *style = diff_words->style;
 851        int minus_first, minus_len, plus_first, plus_len;
 852        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 853        struct diff_options *opt = diff_words->opt;
 854        const char *line_prefix;
 855
 856        if (line[0] != '@' || parse_hunk_header(line, len,
 857                        &minus_first, &minus_len, &plus_first, &plus_len))
 858                return;
 859
 860        assert(opt);
 861        line_prefix = diff_line_prefix(opt);
 862
 863        /* POSIX requires that first be decremented by one if len == 0... */
 864        if (minus_len) {
 865                minus_begin = diff_words->minus.orig[minus_first].begin;
 866                minus_end =
 867                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 868        } else
 869                minus_begin = minus_end =
 870                        diff_words->minus.orig[minus_first].end;
 871
 872        if (plus_len) {
 873                plus_begin = diff_words->plus.orig[plus_first].begin;
 874                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 875        } else
 876                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 877
 878        if (color_words_output_graph_prefix(diff_words)) {
 879                fputs(line_prefix, diff_words->opt->file);
 880        }
 881        if (diff_words->current_plus != plus_begin) {
 882                fn_out_diff_words_write_helper(diff_words->opt->file,
 883                                &style->ctx, style->newline,
 884                                plus_begin - diff_words->current_plus,
 885                                diff_words->current_plus, line_prefix);
 886                if (*(plus_begin - 1) == '\n')
 887                        fputs(line_prefix, diff_words->opt->file);
 888        }
 889        if (minus_begin != minus_end) {
 890                fn_out_diff_words_write_helper(diff_words->opt->file,
 891                                &style->old, style->newline,
 892                                minus_end - minus_begin, minus_begin,
 893                                line_prefix);
 894        }
 895        if (plus_begin != plus_end) {
 896                fn_out_diff_words_write_helper(diff_words->opt->file,
 897                                &style->new, style->newline,
 898                                plus_end - plus_begin, plus_begin,
 899                                line_prefix);
 900        }
 901
 902        diff_words->current_plus = plus_end;
 903        diff_words->last_minus = minus_first;
 904}
 905
 906/* This function starts looking at *begin, and returns 0 iff a word was found. */
 907static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 908                int *begin, int *end)
 909{
 910        if (word_regex && *begin < buffer->size) {
 911                regmatch_t match[1];
 912                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 913                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 914                                        '\n', match[0].rm_eo - match[0].rm_so);
 915                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 916                        *begin += match[0].rm_so;
 917                        return *begin >= *end;
 918                }
 919                return -1;
 920        }
 921
 922        /* find the next word */
 923        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 924                (*begin)++;
 925        if (*begin >= buffer->size)
 926                return -1;
 927
 928        /* find the end of the word */
 929        *end = *begin + 1;
 930        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 931                (*end)++;
 932
 933        return 0;
 934}
 935
 936/*
 937 * This function splits the words in buffer->text, stores the list with
 938 * newline separator into out, and saves the offsets of the original words
 939 * in buffer->orig.
 940 */
 941static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 942                regex_t *word_regex)
 943{
 944        int i, j;
 945        long alloc = 0;
 946
 947        out->size = 0;
 948        out->ptr = NULL;
 949
 950        /* fake an empty "0th" word */
 951        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 952        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 953        buffer->orig_nr = 1;
 954
 955        for (i = 0; i < buffer->text.size; i++) {
 956                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 957                        return;
 958
 959                /* store original boundaries */
 960                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 961                                buffer->orig_alloc);
 962                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 963                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 964                buffer->orig_nr++;
 965
 966                /* store one word */
 967                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 968                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 969                out->ptr[out->size + j - i] = '\n';
 970                out->size += j - i + 1;
 971
 972                i = j - 1;
 973        }
 974}
 975
 976/* this executes the word diff on the accumulated buffers */
 977static void diff_words_show(struct diff_words_data *diff_words)
 978{
 979        xpparam_t xpp;
 980        xdemitconf_t xecfg;
 981        mmfile_t minus, plus;
 982        struct diff_words_style *style = diff_words->style;
 983
 984        struct diff_options *opt = diff_words->opt;
 985        const char *line_prefix;
 986
 987        assert(opt);
 988        line_prefix = diff_line_prefix(opt);
 989
 990        /* special case: only removal */
 991        if (!diff_words->plus.text.size) {
 992                fputs(line_prefix, diff_words->opt->file);
 993                fn_out_diff_words_write_helper(diff_words->opt->file,
 994                        &style->old, style->newline,
 995                        diff_words->minus.text.size,
 996                        diff_words->minus.text.ptr, line_prefix);
 997                diff_words->minus.text.size = 0;
 998                return;
 999        }
1000
1001        diff_words->current_plus = diff_words->plus.text.ptr;
1002        diff_words->last_minus = 0;
1003
1004        memset(&xpp, 0, sizeof(xpp));
1005        memset(&xecfg, 0, sizeof(xecfg));
1006        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1007        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1008        xpp.flags = 0;
1009        /* as only the hunk header will be parsed, we need a 0-context */
1010        xecfg.ctxlen = 0;
1011        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1012                      &xpp, &xecfg);
1013        free(minus.ptr);
1014        free(plus.ptr);
1015        if (diff_words->current_plus != diff_words->plus.text.ptr +
1016                        diff_words->plus.text.size) {
1017                if (color_words_output_graph_prefix(diff_words))
1018                        fputs(line_prefix, diff_words->opt->file);
1019                fn_out_diff_words_write_helper(diff_words->opt->file,
1020                        &style->ctx, style->newline,
1021                        diff_words->plus.text.ptr + diff_words->plus.text.size
1022                        - diff_words->current_plus, diff_words->current_plus,
1023                        line_prefix);
1024        }
1025        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1026}
1027
1028/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1029static void diff_words_flush(struct emit_callback *ecbdata)
1030{
1031        if (ecbdata->diff_words->minus.text.size ||
1032            ecbdata->diff_words->plus.text.size)
1033                diff_words_show(ecbdata->diff_words);
1034}
1035
1036static void diff_filespec_load_driver(struct diff_filespec *one)
1037{
1038        /* Use already-loaded driver */
1039        if (one->driver)
1040                return;
1041
1042        if (S_ISREG(one->mode))
1043                one->driver = userdiff_find_by_path(one->path);
1044
1045        /* Fallback to default settings */
1046        if (!one->driver)
1047                one->driver = userdiff_find_by_name("default");
1048}
1049
1050static const char *userdiff_word_regex(struct diff_filespec *one)
1051{
1052        diff_filespec_load_driver(one);
1053        return one->driver->word_regex;
1054}
1055
1056static void init_diff_words_data(struct emit_callback *ecbdata,
1057                                 struct diff_options *orig_opts,
1058                                 struct diff_filespec *one,
1059                                 struct diff_filespec *two)
1060{
1061        int i;
1062        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1063        memcpy(o, orig_opts, sizeof(struct diff_options));
1064
1065        ecbdata->diff_words =
1066                xcalloc(1, sizeof(struct diff_words_data));
1067        ecbdata->diff_words->type = o->word_diff;
1068        ecbdata->diff_words->opt = o;
1069        if (!o->word_regex)
1070                o->word_regex = userdiff_word_regex(one);
1071        if (!o->word_regex)
1072                o->word_regex = userdiff_word_regex(two);
1073        if (!o->word_regex)
1074                o->word_regex = diff_word_regex_cfg;
1075        if (o->word_regex) {
1076                ecbdata->diff_words->word_regex = (regex_t *)
1077                        xmalloc(sizeof(regex_t));
1078                if (regcomp(ecbdata->diff_words->word_regex,
1079                            o->word_regex,
1080                            REG_EXTENDED | REG_NEWLINE))
1081                        die ("Invalid regular expression: %s",
1082                             o->word_regex);
1083        }
1084        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1085                if (o->word_diff == diff_words_styles[i].type) {
1086                        ecbdata->diff_words->style =
1087                                &diff_words_styles[i];
1088                        break;
1089                }
1090        }
1091        if (want_color(o->use_color)) {
1092                struct diff_words_style *st = ecbdata->diff_words->style;
1093                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1094                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1095                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1096        }
1097}
1098
1099static void free_diff_words_data(struct emit_callback *ecbdata)
1100{
1101        if (ecbdata->diff_words) {
1102                diff_words_flush(ecbdata);
1103                free (ecbdata->diff_words->opt);
1104                free (ecbdata->diff_words->minus.text.ptr);
1105                free (ecbdata->diff_words->minus.orig);
1106                free (ecbdata->diff_words->plus.text.ptr);
1107                free (ecbdata->diff_words->plus.orig);
1108                if (ecbdata->diff_words->word_regex) {
1109                        regfree(ecbdata->diff_words->word_regex);
1110                        free(ecbdata->diff_words->word_regex);
1111                }
1112                free(ecbdata->diff_words);
1113                ecbdata->diff_words = NULL;
1114        }
1115}
1116
1117const char *diff_get_color(int diff_use_color, enum color_diff ix)
1118{
1119        if (want_color(diff_use_color))
1120                return diff_colors[ix];
1121        return "";
1122}
1123
1124const char *diff_line_prefix(struct diff_options *opt)
1125{
1126        struct strbuf *msgbuf;
1127        if (!opt->output_prefix)
1128                return "";
1129
1130        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1131        return msgbuf->buf;
1132}
1133
1134static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1135{
1136        const char *cp;
1137        unsigned long allot;
1138        size_t l = len;
1139
1140        if (ecb->truncate)
1141                return ecb->truncate(line, len);
1142        cp = line;
1143        allot = l;
1144        while (0 < l) {
1145                (void) utf8_width(&cp, &l);
1146                if (!cp)
1147                        break; /* truncated in the middle? */
1148        }
1149        return allot - l;
1150}
1151
1152static void find_lno(const char *line, struct emit_callback *ecbdata)
1153{
1154        const char *p;
1155        ecbdata->lno_in_preimage = 0;
1156        ecbdata->lno_in_postimage = 0;
1157        p = strchr(line, '-');
1158        if (!p)
1159                return; /* cannot happen */
1160        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1161        p = strchr(p, '+');
1162        if (!p)
1163                return; /* cannot happen */
1164        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1165}
1166
1167static void fn_out_consume(void *priv, char *line, unsigned long len)
1168{
1169        struct emit_callback *ecbdata = priv;
1170        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1171        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1172        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1173        struct diff_options *o = ecbdata->opt;
1174        const char *line_prefix = diff_line_prefix(o);
1175
1176        if (ecbdata->header) {
1177                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1178                strbuf_reset(ecbdata->header);
1179                ecbdata->header = NULL;
1180        }
1181        *(ecbdata->found_changesp) = 1;
1182
1183        if (ecbdata->label_path[0]) {
1184                const char *name_a_tab, *name_b_tab;
1185
1186                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1187                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1188
1189                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1190                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1191                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1192                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1193                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1194        }
1195
1196        if (diff_suppress_blank_empty
1197            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1198                line[0] = '\n';
1199                len = 1;
1200        }
1201
1202        if (line[0] == '@') {
1203                if (ecbdata->diff_words)
1204                        diff_words_flush(ecbdata);
1205                len = sane_truncate_line(ecbdata, line, len);
1206                find_lno(line, ecbdata);
1207                emit_hunk_header(ecbdata, line, len);
1208                if (line[len-1] != '\n')
1209                        putc('\n', ecbdata->opt->file);
1210                return;
1211        }
1212
1213        if (len < 1) {
1214                emit_line(ecbdata->opt, reset, reset, line, len);
1215                if (ecbdata->diff_words
1216                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1217                        fputs("~\n", ecbdata->opt->file);
1218                return;
1219        }
1220
1221        if (ecbdata->diff_words) {
1222                if (line[0] == '-') {
1223                        diff_words_append(line, len,
1224                                          &ecbdata->diff_words->minus);
1225                        return;
1226                } else if (line[0] == '+') {
1227                        diff_words_append(line, len,
1228                                          &ecbdata->diff_words->plus);
1229                        return;
1230                } else if (starts_with(line, "\\ ")) {
1231                        /*
1232                         * Eat the "no newline at eof" marker as if we
1233                         * saw a "+" or "-" line with nothing on it,
1234                         * and return without diff_words_flush() to
1235                         * defer processing. If this is the end of
1236                         * preimage, more "+" lines may come after it.
1237                         */
1238                        return;
1239                }
1240                diff_words_flush(ecbdata);
1241                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1242                        emit_line(ecbdata->opt, plain, reset, line, len);
1243                        fputs("~\n", ecbdata->opt->file);
1244                } else {
1245                        /*
1246                         * Skip the prefix character, if any.  With
1247                         * diff_suppress_blank_empty, there may be
1248                         * none.
1249                         */
1250                        if (line[0] != '\n') {
1251                              line++;
1252                              len--;
1253                        }
1254                        emit_line(ecbdata->opt, plain, reset, line, len);
1255                }
1256                return;
1257        }
1258
1259        if (line[0] != '+') {
1260                const char *color =
1261                        diff_get_color(ecbdata->color_diff,
1262                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1263                ecbdata->lno_in_preimage++;
1264                if (line[0] == ' ')
1265                        ecbdata->lno_in_postimage++;
1266                emit_line(ecbdata->opt, color, reset, line, len);
1267        } else {
1268                ecbdata->lno_in_postimage++;
1269                emit_add_line(reset, ecbdata, line + 1, len - 1);
1270        }
1271}
1272
1273static char *pprint_rename(const char *a, const char *b)
1274{
1275        const char *old = a;
1276        const char *new = b;
1277        struct strbuf name = STRBUF_INIT;
1278        int pfx_length, sfx_length;
1279        int pfx_adjust_for_slash;
1280        int len_a = strlen(a);
1281        int len_b = strlen(b);
1282        int a_midlen, b_midlen;
1283        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1284        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1285
1286        if (qlen_a || qlen_b) {
1287                quote_c_style(a, &name, NULL, 0);
1288                strbuf_addstr(&name, " => ");
1289                quote_c_style(b, &name, NULL, 0);
1290                return strbuf_detach(&name, NULL);
1291        }
1292
1293        /* Find common prefix */
1294        pfx_length = 0;
1295        while (*old && *new && *old == *new) {
1296                if (*old == '/')
1297                        pfx_length = old - a + 1;
1298                old++;
1299                new++;
1300        }
1301
1302        /* Find common suffix */
1303        old = a + len_a;
1304        new = b + len_b;
1305        sfx_length = 0;
1306        /*
1307         * If there is a common prefix, it must end in a slash.  In
1308         * that case we let this loop run 1 into the prefix to see the
1309         * same slash.
1310         *
1311         * If there is no common prefix, we cannot do this as it would
1312         * underrun the input strings.
1313         */
1314        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1315        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1316               b + pfx_length - pfx_adjust_for_slash <= new &&
1317               *old == *new) {
1318                if (*old == '/')
1319                        sfx_length = len_a - (old - a);
1320                old--;
1321                new--;
1322        }
1323
1324        /*
1325         * pfx{mid-a => mid-b}sfx
1326         * {pfx-a => pfx-b}sfx
1327         * pfx{sfx-a => sfx-b}
1328         * name-a => name-b
1329         */
1330        a_midlen = len_a - pfx_length - sfx_length;
1331        b_midlen = len_b - pfx_length - sfx_length;
1332        if (a_midlen < 0)
1333                a_midlen = 0;
1334        if (b_midlen < 0)
1335                b_midlen = 0;
1336
1337        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1338        if (pfx_length + sfx_length) {
1339                strbuf_add(&name, a, pfx_length);
1340                strbuf_addch(&name, '{');
1341        }
1342        strbuf_add(&name, a + pfx_length, a_midlen);
1343        strbuf_addstr(&name, " => ");
1344        strbuf_add(&name, b + pfx_length, b_midlen);
1345        if (pfx_length + sfx_length) {
1346                strbuf_addch(&name, '}');
1347                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1348        }
1349        return strbuf_detach(&name, NULL);
1350}
1351
1352struct diffstat_t {
1353        int nr;
1354        int alloc;
1355        struct diffstat_file {
1356                char *from_name;
1357                char *name;
1358                char *print_name;
1359                unsigned is_unmerged:1;
1360                unsigned is_binary:1;
1361                unsigned is_renamed:1;
1362                unsigned is_interesting:1;
1363                uintmax_t added, deleted;
1364        } **files;
1365};
1366
1367static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1368                                          const char *name_a,
1369                                          const char *name_b)
1370{
1371        struct diffstat_file *x;
1372        x = xcalloc(1, sizeof(*x));
1373        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1374        diffstat->files[diffstat->nr++] = x;
1375        if (name_b) {
1376                x->from_name = xstrdup(name_a);
1377                x->name = xstrdup(name_b);
1378                x->is_renamed = 1;
1379        }
1380        else {
1381                x->from_name = NULL;
1382                x->name = xstrdup(name_a);
1383        }
1384        return x;
1385}
1386
1387static void diffstat_consume(void *priv, char *line, unsigned long len)
1388{
1389        struct diffstat_t *diffstat = priv;
1390        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1391
1392        if (line[0] == '+')
1393                x->added++;
1394        else if (line[0] == '-')
1395                x->deleted++;
1396}
1397
1398const char mime_boundary_leader[] = "------------";
1399
1400static int scale_linear(int it, int width, int max_change)
1401{
1402        if (!it)
1403                return 0;
1404        /*
1405         * make sure that at least one '-' or '+' is printed if
1406         * there is any change to this path. The easiest way is to
1407         * scale linearly as if the alloted width is one column shorter
1408         * than it is, and then add 1 to the result.
1409         */
1410        return 1 + (it * (width - 1) / max_change);
1411}
1412
1413static void show_name(FILE *file,
1414                      const char *prefix, const char *name, int len)
1415{
1416        fprintf(file, " %s%-*s |", prefix, len, name);
1417}
1418
1419static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1420{
1421        if (cnt <= 0)
1422                return;
1423        fprintf(file, "%s", set);
1424        while (cnt--)
1425                putc(ch, file);
1426        fprintf(file, "%s", reset);
1427}
1428
1429static void fill_print_name(struct diffstat_file *file)
1430{
1431        char *pname;
1432
1433        if (file->print_name)
1434                return;
1435
1436        if (!file->is_renamed) {
1437                struct strbuf buf = STRBUF_INIT;
1438                if (quote_c_style(file->name, &buf, NULL, 0)) {
1439                        pname = strbuf_detach(&buf, NULL);
1440                } else {
1441                        pname = file->name;
1442                        strbuf_release(&buf);
1443                }
1444        } else {
1445                pname = pprint_rename(file->from_name, file->name);
1446        }
1447        file->print_name = pname;
1448}
1449
1450int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1451{
1452        struct strbuf sb = STRBUF_INIT;
1453        int ret;
1454
1455        if (!files) {
1456                assert(insertions == 0 && deletions == 0);
1457                return fprintf(fp, "%s\n", " 0 files changed");
1458        }
1459
1460        strbuf_addf(&sb,
1461                    (files == 1) ? " %d file changed" : " %d files changed",
1462                    files);
1463
1464        /*
1465         * For binary diff, the caller may want to print "x files
1466         * changed" with insertions == 0 && deletions == 0.
1467         *
1468         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1469         * is probably less confusing (i.e skip over "2 files changed
1470         * but nothing about added/removed lines? Is this a bug in Git?").
1471         */
1472        if (insertions || deletions == 0) {
1473                strbuf_addf(&sb,
1474                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1475                            insertions);
1476        }
1477
1478        if (deletions || insertions == 0) {
1479                strbuf_addf(&sb,
1480                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1481                            deletions);
1482        }
1483        strbuf_addch(&sb, '\n');
1484        ret = fputs(sb.buf, fp);
1485        strbuf_release(&sb);
1486        return ret;
1487}
1488
1489static void show_stats(struct diffstat_t *data, struct diff_options *options)
1490{
1491        int i, len, add, del, adds = 0, dels = 0;
1492        uintmax_t max_change = 0, max_len = 0;
1493        int total_files = data->nr, count;
1494        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1495        const char *reset, *add_c, *del_c;
1496        const char *line_prefix = "";
1497        int extra_shown = 0;
1498
1499        if (data->nr == 0)
1500                return;
1501
1502        line_prefix = diff_line_prefix(options);
1503        count = options->stat_count ? options->stat_count : data->nr;
1504
1505        reset = diff_get_color_opt(options, DIFF_RESET);
1506        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1507        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1508
1509        /*
1510         * Find the longest filename and max number of changes
1511         */
1512        for (i = 0; (i < count) && (i < data->nr); i++) {
1513                struct diffstat_file *file = data->files[i];
1514                uintmax_t change = file->added + file->deleted;
1515
1516                if (!file->is_interesting && (change == 0)) {
1517                        count++; /* not shown == room for one more */
1518                        continue;
1519                }
1520                fill_print_name(file);
1521                len = strlen(file->print_name);
1522                if (max_len < len)
1523                        max_len = len;
1524
1525                if (file->is_unmerged) {
1526                        /* "Unmerged" is 8 characters */
1527                        bin_width = bin_width < 8 ? 8 : bin_width;
1528                        continue;
1529                }
1530                if (file->is_binary) {
1531                        /* "Bin XXX -> YYY bytes" */
1532                        int w = 14 + decimal_width(file->added)
1533                                + decimal_width(file->deleted);
1534                        bin_width = bin_width < w ? w : bin_width;
1535                        /* Display change counts aligned with "Bin" */
1536                        number_width = 3;
1537                        continue;
1538                }
1539
1540                if (max_change < change)
1541                        max_change = change;
1542        }
1543        count = i; /* where we can stop scanning in data->files[] */
1544
1545        /*
1546         * We have width = stat_width or term_columns() columns total.
1547         * We want a maximum of min(max_len, stat_name_width) for the name part.
1548         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1549         * We also need 1 for " " and 4 + decimal_width(max_change)
1550         * for " | NNNN " and one the empty column at the end, altogether
1551         * 6 + decimal_width(max_change).
1552         *
1553         * If there's not enough space, we will use the smaller of
1554         * stat_name_width (if set) and 5/8*width for the filename,
1555         * and the rest for constant elements + graph part, but no more
1556         * than stat_graph_width for the graph part.
1557         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1558         * for the standard terminal size).
1559         *
1560         * In other words: stat_width limits the maximum width, and
1561         * stat_name_width fixes the maximum width of the filename,
1562         * and is also used to divide available columns if there
1563         * aren't enough.
1564         *
1565         * Binary files are displayed with "Bin XXX -> YYY bytes"
1566         * instead of the change count and graph. This part is treated
1567         * similarly to the graph part, except that it is not
1568         * "scaled". If total width is too small to accommodate the
1569         * guaranteed minimum width of the filename part and the
1570         * separators and this message, this message will "overflow"
1571         * making the line longer than the maximum width.
1572         */
1573
1574        if (options->stat_width == -1)
1575                width = term_columns() - options->output_prefix_length;
1576        else
1577                width = options->stat_width ? options->stat_width : 80;
1578        number_width = decimal_width(max_change) > number_width ?
1579                decimal_width(max_change) : number_width;
1580
1581        if (options->stat_graph_width == -1)
1582                options->stat_graph_width = diff_stat_graph_width;
1583
1584        /*
1585         * Guarantee 3/8*16==6 for the graph part
1586         * and 5/8*16==10 for the filename part
1587         */
1588        if (width < 16 + 6 + number_width)
1589                width = 16 + 6 + number_width;
1590
1591        /*
1592         * First assign sizes that are wanted, ignoring available width.
1593         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1594         * starting from "XXX" should fit in graph_width.
1595         */
1596        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1597        if (options->stat_graph_width &&
1598            options->stat_graph_width < graph_width)
1599                graph_width = options->stat_graph_width;
1600
1601        name_width = (options->stat_name_width > 0 &&
1602                      options->stat_name_width < max_len) ?
1603                options->stat_name_width : max_len;
1604
1605        /*
1606         * Adjust adjustable widths not to exceed maximum width
1607         */
1608        if (name_width + number_width + 6 + graph_width > width) {
1609                if (graph_width > width * 3/8 - number_width - 6) {
1610                        graph_width = width * 3/8 - number_width - 6;
1611                        if (graph_width < 6)
1612                                graph_width = 6;
1613                }
1614
1615                if (options->stat_graph_width &&
1616                    graph_width > options->stat_graph_width)
1617                        graph_width = options->stat_graph_width;
1618                if (name_width > width - number_width - 6 - graph_width)
1619                        name_width = width - number_width - 6 - graph_width;
1620                else
1621                        graph_width = width - number_width - 6 - name_width;
1622        }
1623
1624        /*
1625         * From here name_width is the width of the name area,
1626         * and graph_width is the width of the graph area.
1627         * max_change is used to scale graph properly.
1628         */
1629        for (i = 0; i < count; i++) {
1630                const char *prefix = "";
1631                struct diffstat_file *file = data->files[i];
1632                char *name = file->print_name;
1633                uintmax_t added = file->added;
1634                uintmax_t deleted = file->deleted;
1635                int name_len;
1636
1637                if (!file->is_interesting && (added + deleted == 0))
1638                        continue;
1639
1640                /*
1641                 * "scale" the filename
1642                 */
1643                len = name_width;
1644                name_len = strlen(name);
1645                if (name_width < name_len) {
1646                        char *slash;
1647                        prefix = "...";
1648                        len -= 3;
1649                        name += name_len - len;
1650                        slash = strchr(name, '/');
1651                        if (slash)
1652                                name = slash;
1653                }
1654
1655                if (file->is_binary) {
1656                        fprintf(options->file, "%s", line_prefix);
1657                        show_name(options->file, prefix, name, len);
1658                        fprintf(options->file, " %*s", number_width, "Bin");
1659                        if (!added && !deleted) {
1660                                putc('\n', options->file);
1661                                continue;
1662                        }
1663                        fprintf(options->file, " %s%"PRIuMAX"%s",
1664                                del_c, deleted, reset);
1665                        fprintf(options->file, " -> ");
1666                        fprintf(options->file, "%s%"PRIuMAX"%s",
1667                                add_c, added, reset);
1668                        fprintf(options->file, " bytes");
1669                        fprintf(options->file, "\n");
1670                        continue;
1671                }
1672                else if (file->is_unmerged) {
1673                        fprintf(options->file, "%s", line_prefix);
1674                        show_name(options->file, prefix, name, len);
1675                        fprintf(options->file, " Unmerged\n");
1676                        continue;
1677                }
1678
1679                /*
1680                 * scale the add/delete
1681                 */
1682                add = added;
1683                del = deleted;
1684
1685                if (graph_width <= max_change) {
1686                        int total = scale_linear(add + del, graph_width, max_change);
1687                        if (total < 2 && add && del)
1688                                /* width >= 2 due to the sanity check */
1689                                total = 2;
1690                        if (add < del) {
1691                                add = scale_linear(add, graph_width, max_change);
1692                                del = total - add;
1693                        } else {
1694                                del = scale_linear(del, graph_width, max_change);
1695                                add = total - del;
1696                        }
1697                }
1698                fprintf(options->file, "%s", line_prefix);
1699                show_name(options->file, prefix, name, len);
1700                fprintf(options->file, " %*"PRIuMAX"%s",
1701                        number_width, added + deleted,
1702                        added + deleted ? " " : "");
1703                show_graph(options->file, '+', add, add_c, reset);
1704                show_graph(options->file, '-', del, del_c, reset);
1705                fprintf(options->file, "\n");
1706        }
1707
1708        for (i = 0; i < data->nr; i++) {
1709                struct diffstat_file *file = data->files[i];
1710                uintmax_t added = file->added;
1711                uintmax_t deleted = file->deleted;
1712
1713                if (file->is_unmerged ||
1714                    (!file->is_interesting && (added + deleted == 0))) {
1715                        total_files--;
1716                        continue;
1717                }
1718
1719                if (!file->is_binary) {
1720                        adds += added;
1721                        dels += deleted;
1722                }
1723                if (i < count)
1724                        continue;
1725                if (!extra_shown)
1726                        fprintf(options->file, "%s ...\n", line_prefix);
1727                extra_shown = 1;
1728        }
1729        fprintf(options->file, "%s", line_prefix);
1730        print_stat_summary(options->file, total_files, adds, dels);
1731}
1732
1733static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1734{
1735        int i, adds = 0, dels = 0, total_files = data->nr;
1736
1737        if (data->nr == 0)
1738                return;
1739
1740        for (i = 0; i < data->nr; i++) {
1741                int added = data->files[i]->added;
1742                int deleted= data->files[i]->deleted;
1743
1744                if (data->files[i]->is_unmerged ||
1745                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1746                        total_files--;
1747                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1748                        adds += added;
1749                        dels += deleted;
1750                }
1751        }
1752        fprintf(options->file, "%s", diff_line_prefix(options));
1753        print_stat_summary(options->file, total_files, adds, dels);
1754}
1755
1756static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1757{
1758        int i;
1759
1760        if (data->nr == 0)
1761                return;
1762
1763        for (i = 0; i < data->nr; i++) {
1764                struct diffstat_file *file = data->files[i];
1765
1766                fprintf(options->file, "%s", diff_line_prefix(options));
1767
1768                if (file->is_binary)
1769                        fprintf(options->file, "-\t-\t");
1770                else
1771                        fprintf(options->file,
1772                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1773                                file->added, file->deleted);
1774                if (options->line_termination) {
1775                        fill_print_name(file);
1776                        if (!file->is_renamed)
1777                                write_name_quoted(file->name, options->file,
1778                                                  options->line_termination);
1779                        else {
1780                                fputs(file->print_name, options->file);
1781                                putc(options->line_termination, options->file);
1782                        }
1783                } else {
1784                        if (file->is_renamed) {
1785                                putc('\0', options->file);
1786                                write_name_quoted(file->from_name, options->file, '\0');
1787                        }
1788                        write_name_quoted(file->name, options->file, '\0');
1789                }
1790        }
1791}
1792
1793struct dirstat_file {
1794        const char *name;
1795        unsigned long changed;
1796};
1797
1798struct dirstat_dir {
1799        struct dirstat_file *files;
1800        int alloc, nr, permille, cumulative;
1801};
1802
1803static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1804                unsigned long changed, const char *base, int baselen)
1805{
1806        unsigned long this_dir = 0;
1807        unsigned int sources = 0;
1808        const char *line_prefix = diff_line_prefix(opt);
1809
1810        while (dir->nr) {
1811                struct dirstat_file *f = dir->files;
1812                int namelen = strlen(f->name);
1813                unsigned long this;
1814                char *slash;
1815
1816                if (namelen < baselen)
1817                        break;
1818                if (memcmp(f->name, base, baselen))
1819                        break;
1820                slash = strchr(f->name + baselen, '/');
1821                if (slash) {
1822                        int newbaselen = slash + 1 - f->name;
1823                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1824                        sources++;
1825                } else {
1826                        this = f->changed;
1827                        dir->files++;
1828                        dir->nr--;
1829                        sources += 2;
1830                }
1831                this_dir += this;
1832        }
1833
1834        /*
1835         * We don't report dirstat's for
1836         *  - the top level
1837         *  - or cases where everything came from a single directory
1838         *    under this directory (sources == 1).
1839         */
1840        if (baselen && sources != 1) {
1841                if (this_dir) {
1842                        int permille = this_dir * 1000 / changed;
1843                        if (permille >= dir->permille) {
1844                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1845                                        permille / 10, permille % 10, baselen, base);
1846                                if (!dir->cumulative)
1847                                        return 0;
1848                        }
1849                }
1850        }
1851        return this_dir;
1852}
1853
1854static int dirstat_compare(const void *_a, const void *_b)
1855{
1856        const struct dirstat_file *a = _a;
1857        const struct dirstat_file *b = _b;
1858        return strcmp(a->name, b->name);
1859}
1860
1861static void show_dirstat(struct diff_options *options)
1862{
1863        int i;
1864        unsigned long changed;
1865        struct dirstat_dir dir;
1866        struct diff_queue_struct *q = &diff_queued_diff;
1867
1868        dir.files = NULL;
1869        dir.alloc = 0;
1870        dir.nr = 0;
1871        dir.permille = options->dirstat_permille;
1872        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1873
1874        changed = 0;
1875        for (i = 0; i < q->nr; i++) {
1876                struct diff_filepair *p = q->queue[i];
1877                const char *name;
1878                unsigned long copied, added, damage;
1879                int content_changed;
1880
1881                name = p->two->path ? p->two->path : p->one->path;
1882
1883                if (p->one->sha1_valid && p->two->sha1_valid)
1884                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1885                else
1886                        content_changed = 1;
1887
1888                if (!content_changed) {
1889                        /*
1890                         * The SHA1 has not changed, so pre-/post-content is
1891                         * identical. We can therefore skip looking at the
1892                         * file contents altogether.
1893                         */
1894                        damage = 0;
1895                        goto found_damage;
1896                }
1897
1898                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1899                        /*
1900                         * In --dirstat-by-file mode, we don't really need to
1901                         * look at the actual file contents at all.
1902                         * The fact that the SHA1 changed is enough for us to
1903                         * add this file to the list of results
1904                         * (with each file contributing equal damage).
1905                         */
1906                        damage = 1;
1907                        goto found_damage;
1908                }
1909
1910                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1911                        diff_populate_filespec(p->one, 0);
1912                        diff_populate_filespec(p->two, 0);
1913                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1914                                               &copied, &added);
1915                        diff_free_filespec_data(p->one);
1916                        diff_free_filespec_data(p->two);
1917                } else if (DIFF_FILE_VALID(p->one)) {
1918                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1919                        copied = added = 0;
1920                        diff_free_filespec_data(p->one);
1921                } else if (DIFF_FILE_VALID(p->two)) {
1922                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1923                        copied = 0;
1924                        added = p->two->size;
1925                        diff_free_filespec_data(p->two);
1926                } else
1927                        continue;
1928
1929                /*
1930                 * Original minus copied is the removed material,
1931                 * added is the new material.  They are both damages
1932                 * made to the preimage.
1933                 * If the resulting damage is zero, we know that
1934                 * diffcore_count_changes() considers the two entries to
1935                 * be identical, but since content_changed is true, we
1936                 * know that there must have been _some_ kind of change,
1937                 * so we force all entries to have damage > 0.
1938                 */
1939                damage = (p->one->size - copied) + added;
1940                if (!damage)
1941                        damage = 1;
1942
1943found_damage:
1944                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1945                dir.files[dir.nr].name = name;
1946                dir.files[dir.nr].changed = damage;
1947                changed += damage;
1948                dir.nr++;
1949        }
1950
1951        /* This can happen even with many files, if everything was renames */
1952        if (!changed)
1953                return;
1954
1955        /* Show all directories with more than x% of the changes */
1956        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1957        gather_dirstat(options, &dir, changed, "", 0);
1958}
1959
1960static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1961{
1962        int i;
1963        unsigned long changed;
1964        struct dirstat_dir dir;
1965
1966        if (data->nr == 0)
1967                return;
1968
1969        dir.files = NULL;
1970        dir.alloc = 0;
1971        dir.nr = 0;
1972        dir.permille = options->dirstat_permille;
1973        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1974
1975        changed = 0;
1976        for (i = 0; i < data->nr; i++) {
1977                struct diffstat_file *file = data->files[i];
1978                unsigned long damage = file->added + file->deleted;
1979                if (file->is_binary)
1980                        /*
1981                         * binary files counts bytes, not lines. Must find some
1982                         * way to normalize binary bytes vs. textual lines.
1983                         * The following heuristic assumes that there are 64
1984                         * bytes per "line".
1985                         * This is stupid and ugly, but very cheap...
1986                         */
1987                        damage = (damage + 63) / 64;
1988                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1989                dir.files[dir.nr].name = file->name;
1990                dir.files[dir.nr].changed = damage;
1991                changed += damage;
1992                dir.nr++;
1993        }
1994
1995        /* This can happen even with many files, if everything was renames */
1996        if (!changed)
1997                return;
1998
1999        /* Show all directories with more than x% of the changes */
2000        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2001        gather_dirstat(options, &dir, changed, "", 0);
2002}
2003
2004static void free_diffstat_info(struct diffstat_t *diffstat)
2005{
2006        int i;
2007        for (i = 0; i < diffstat->nr; i++) {
2008                struct diffstat_file *f = diffstat->files[i];
2009                if (f->name != f->print_name)
2010                        free(f->print_name);
2011                free(f->name);
2012                free(f->from_name);
2013                free(f);
2014        }
2015        free(diffstat->files);
2016}
2017
2018struct checkdiff_t {
2019        const char *filename;
2020        int lineno;
2021        int conflict_marker_size;
2022        struct diff_options *o;
2023        unsigned ws_rule;
2024        unsigned status;
2025};
2026
2027static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2028{
2029        char firstchar;
2030        int cnt;
2031
2032        if (len < marker_size + 1)
2033                return 0;
2034        firstchar = line[0];
2035        switch (firstchar) {
2036        case '=': case '>': case '<': case '|':
2037                break;
2038        default:
2039                return 0;
2040        }
2041        for (cnt = 1; cnt < marker_size; cnt++)
2042                if (line[cnt] != firstchar)
2043                        return 0;
2044        /* line[1] thru line[marker_size-1] are same as firstchar */
2045        if (len < marker_size + 1 || !isspace(line[marker_size]))
2046                return 0;
2047        return 1;
2048}
2049
2050static void checkdiff_consume(void *priv, char *line, unsigned long len)
2051{
2052        struct checkdiff_t *data = priv;
2053        int marker_size = data->conflict_marker_size;
2054        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2055        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2056        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2057        char *err;
2058        const char *line_prefix;
2059
2060        assert(data->o);
2061        line_prefix = diff_line_prefix(data->o);
2062
2063        if (line[0] == '+') {
2064                unsigned bad;
2065                data->lineno++;
2066                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2067                        data->status |= 1;
2068                        fprintf(data->o->file,
2069                                "%s%s:%d: leftover conflict marker\n",
2070                                line_prefix, data->filename, data->lineno);
2071                }
2072                bad = ws_check(line + 1, len - 1, data->ws_rule);
2073                if (!bad)
2074                        return;
2075                data->status |= bad;
2076                err = whitespace_error_string(bad);
2077                fprintf(data->o->file, "%s%s:%d: %s.\n",
2078                        line_prefix, data->filename, data->lineno, err);
2079                free(err);
2080                emit_line(data->o, set, reset, line, 1);
2081                ws_check_emit(line + 1, len - 1, data->ws_rule,
2082                              data->o->file, set, reset, ws);
2083        } else if (line[0] == ' ') {
2084                data->lineno++;
2085        } else if (line[0] == '@') {
2086                char *plus = strchr(line, '+');
2087                if (plus)
2088                        data->lineno = strtol(plus, NULL, 10) - 1;
2089                else
2090                        die("invalid diff");
2091        }
2092}
2093
2094static unsigned char *deflate_it(char *data,
2095                                 unsigned long size,
2096                                 unsigned long *result_size)
2097{
2098        int bound;
2099        unsigned char *deflated;
2100        git_zstream stream;
2101
2102        git_deflate_init(&stream, zlib_compression_level);
2103        bound = git_deflate_bound(&stream, size);
2104        deflated = xmalloc(bound);
2105        stream.next_out = deflated;
2106        stream.avail_out = bound;
2107
2108        stream.next_in = (unsigned char *)data;
2109        stream.avail_in = size;
2110        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2111                ; /* nothing */
2112        git_deflate_end(&stream);
2113        *result_size = stream.total_out;
2114        return deflated;
2115}
2116
2117static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2118                                  const char *prefix)
2119{
2120        void *cp;
2121        void *delta;
2122        void *deflated;
2123        void *data;
2124        unsigned long orig_size;
2125        unsigned long delta_size;
2126        unsigned long deflate_size;
2127        unsigned long data_size;
2128
2129        /* We could do deflated delta, or we could do just deflated two,
2130         * whichever is smaller.
2131         */
2132        delta = NULL;
2133        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2134        if (one->size && two->size) {
2135                delta = diff_delta(one->ptr, one->size,
2136                                   two->ptr, two->size,
2137                                   &delta_size, deflate_size);
2138                if (delta) {
2139                        void *to_free = delta;
2140                        orig_size = delta_size;
2141                        delta = deflate_it(delta, delta_size, &delta_size);
2142                        free(to_free);
2143                }
2144        }
2145
2146        if (delta && delta_size < deflate_size) {
2147                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2148                free(deflated);
2149                data = delta;
2150                data_size = delta_size;
2151        }
2152        else {
2153                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2154                free(delta);
2155                data = deflated;
2156                data_size = deflate_size;
2157        }
2158
2159        /* emit data encoded in base85 */
2160        cp = data;
2161        while (data_size) {
2162                int bytes = (52 < data_size) ? 52 : data_size;
2163                char line[70];
2164                data_size -= bytes;
2165                if (bytes <= 26)
2166                        line[0] = bytes + 'A' - 1;
2167                else
2168                        line[0] = bytes - 26 + 'a' - 1;
2169                encode_85(line + 1, cp, bytes);
2170                cp = (char *) cp + bytes;
2171                fprintf(file, "%s", prefix);
2172                fputs(line, file);
2173                fputc('\n', file);
2174        }
2175        fprintf(file, "%s\n", prefix);
2176        free(data);
2177}
2178
2179static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2180                             const char *prefix)
2181{
2182        fprintf(file, "%sGIT binary patch\n", prefix);
2183        emit_binary_diff_body(file, one, two, prefix);
2184        emit_binary_diff_body(file, two, one, prefix);
2185}
2186
2187int diff_filespec_is_binary(struct diff_filespec *one)
2188{
2189        if (one->is_binary == -1) {
2190                diff_filespec_load_driver(one);
2191                if (one->driver->binary != -1)
2192                        one->is_binary = one->driver->binary;
2193                else {
2194                        if (!one->data && DIFF_FILE_VALID(one))
2195                                diff_populate_filespec(one, CHECK_BINARY);
2196                        if (one->is_binary == -1 && one->data)
2197                                one->is_binary = buffer_is_binary(one->data,
2198                                                one->size);
2199                        if (one->is_binary == -1)
2200                                one->is_binary = 0;
2201                }
2202        }
2203        return one->is_binary;
2204}
2205
2206static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2207{
2208        diff_filespec_load_driver(one);
2209        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2210}
2211
2212void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2213{
2214        if (!options->a_prefix)
2215                options->a_prefix = a;
2216        if (!options->b_prefix)
2217                options->b_prefix = b;
2218}
2219
2220struct userdiff_driver *get_textconv(struct diff_filespec *one)
2221{
2222        if (!DIFF_FILE_VALID(one))
2223                return NULL;
2224
2225        diff_filespec_load_driver(one);
2226        return userdiff_get_textconv(one->driver);
2227}
2228
2229static void builtin_diff(const char *name_a,
2230                         const char *name_b,
2231                         struct diff_filespec *one,
2232                         struct diff_filespec *two,
2233                         const char *xfrm_msg,
2234                         int must_show_header,
2235                         struct diff_options *o,
2236                         int complete_rewrite)
2237{
2238        mmfile_t mf1, mf2;
2239        const char *lbl[2];
2240        char *a_one, *b_two;
2241        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2242        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2243        const char *a_prefix, *b_prefix;
2244        struct userdiff_driver *textconv_one = NULL;
2245        struct userdiff_driver *textconv_two = NULL;
2246        struct strbuf header = STRBUF_INIT;
2247        const char *line_prefix = diff_line_prefix(o);
2248
2249        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2250                        (!one->mode || S_ISGITLINK(one->mode)) &&
2251                        (!two->mode || S_ISGITLINK(two->mode))) {
2252                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2253                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2254                show_submodule_summary(o->file, one->path ? one->path : two->path,
2255                                line_prefix,
2256                                one->sha1, two->sha1, two->dirty_submodule,
2257                                meta, del, add, reset);
2258                return;
2259        }
2260
2261        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2262                textconv_one = get_textconv(one);
2263                textconv_two = get_textconv(two);
2264        }
2265
2266        diff_set_mnemonic_prefix(o, "a/", "b/");
2267        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2268                a_prefix = o->b_prefix;
2269                b_prefix = o->a_prefix;
2270        } else {
2271                a_prefix = o->a_prefix;
2272                b_prefix = o->b_prefix;
2273        }
2274
2275        /* Never use a non-valid filename anywhere if at all possible */
2276        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2277        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2278
2279        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2280        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2281        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2282        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2283        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2284        if (lbl[0][0] == '/') {
2285                /* /dev/null */
2286                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2287                if (xfrm_msg)
2288                        strbuf_addstr(&header, xfrm_msg);
2289                must_show_header = 1;
2290        }
2291        else if (lbl[1][0] == '/') {
2292                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2293                if (xfrm_msg)
2294                        strbuf_addstr(&header, xfrm_msg);
2295                must_show_header = 1;
2296        }
2297        else {
2298                if (one->mode != two->mode) {
2299                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2300                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2301                        must_show_header = 1;
2302                }
2303                if (xfrm_msg)
2304                        strbuf_addstr(&header, xfrm_msg);
2305
2306                /*
2307                 * we do not run diff between different kind
2308                 * of objects.
2309                 */
2310                if ((one->mode ^ two->mode) & S_IFMT)
2311                        goto free_ab_and_return;
2312                if (complete_rewrite &&
2313                    (textconv_one || !diff_filespec_is_binary(one)) &&
2314                    (textconv_two || !diff_filespec_is_binary(two))) {
2315                        fprintf(o->file, "%s", header.buf);
2316                        strbuf_reset(&header);
2317                        emit_rewrite_diff(name_a, name_b, one, two,
2318                                                textconv_one, textconv_two, o);
2319                        o->found_changes = 1;
2320                        goto free_ab_and_return;
2321                }
2322        }
2323
2324        if (o->irreversible_delete && lbl[1][0] == '/') {
2325                fprintf(o->file, "%s", header.buf);
2326                strbuf_reset(&header);
2327                goto free_ab_and_return;
2328        } else if (!DIFF_OPT_TST(o, TEXT) &&
2329            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2330              (!textconv_two && diff_filespec_is_binary(two)) )) {
2331                if (!one->data && !two->data &&
2332                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2333                    !DIFF_OPT_TST(o, BINARY)) {
2334                        if (!hashcmp(one->sha1, two->sha1)) {
2335                                if (must_show_header)
2336                                        fprintf(o->file, "%s", header.buf);
2337                                goto free_ab_and_return;
2338                        }
2339                        fprintf(o->file, "%s", header.buf);
2340                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2341                                line_prefix, lbl[0], lbl[1]);
2342                        goto free_ab_and_return;
2343                }
2344                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2345                        die("unable to read files to diff");
2346                /* Quite common confusing case */
2347                if (mf1.size == mf2.size &&
2348                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2349                        if (must_show_header)
2350                                fprintf(o->file, "%s", header.buf);
2351                        goto free_ab_and_return;
2352                }
2353                fprintf(o->file, "%s", header.buf);
2354                strbuf_reset(&header);
2355                if (DIFF_OPT_TST(o, BINARY))
2356                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2357                else
2358                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2359                                line_prefix, lbl[0], lbl[1]);
2360                o->found_changes = 1;
2361        } else {
2362                /* Crazy xdl interfaces.. */
2363                const char *diffopts = getenv("GIT_DIFF_OPTS");
2364                const char *v;
2365                xpparam_t xpp;
2366                xdemitconf_t xecfg;
2367                struct emit_callback ecbdata;
2368                const struct userdiff_funcname *pe;
2369
2370                if (must_show_header) {
2371                        fprintf(o->file, "%s", header.buf);
2372                        strbuf_reset(&header);
2373                }
2374
2375                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2376                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2377
2378                pe = diff_funcname_pattern(one);
2379                if (!pe)
2380                        pe = diff_funcname_pattern(two);
2381
2382                memset(&xpp, 0, sizeof(xpp));
2383                memset(&xecfg, 0, sizeof(xecfg));
2384                memset(&ecbdata, 0, sizeof(ecbdata));
2385                ecbdata.label_path = lbl;
2386                ecbdata.color_diff = want_color(o->use_color);
2387                ecbdata.found_changesp = &o->found_changes;
2388                ecbdata.ws_rule = whitespace_rule(name_b);
2389                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2390                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2391                ecbdata.opt = o;
2392                ecbdata.header = header.len ? &header : NULL;
2393                xpp.flags = o->xdl_opts;
2394                xecfg.ctxlen = o->context;
2395                xecfg.interhunkctxlen = o->interhunkcontext;
2396                xecfg.flags = XDL_EMIT_FUNCNAMES;
2397                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2398                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2399                if (pe)
2400                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2401                if (!diffopts)
2402                        ;
2403                else if (skip_prefix(diffopts, "--unified=", &v))
2404                        xecfg.ctxlen = strtoul(v, NULL, 10);
2405                else if (skip_prefix(diffopts, "-u", &v))
2406                        xecfg.ctxlen = strtoul(v, NULL, 10);
2407                if (o->word_diff)
2408                        init_diff_words_data(&ecbdata, o, one, two);
2409                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2410                              &xpp, &xecfg);
2411                if (o->word_diff)
2412                        free_diff_words_data(&ecbdata);
2413                if (textconv_one)
2414                        free(mf1.ptr);
2415                if (textconv_two)
2416                        free(mf2.ptr);
2417                xdiff_clear_find_func(&xecfg);
2418        }
2419
2420 free_ab_and_return:
2421        strbuf_release(&header);
2422        diff_free_filespec_data(one);
2423        diff_free_filespec_data(two);
2424        free(a_one);
2425        free(b_two);
2426        return;
2427}
2428
2429static void builtin_diffstat(const char *name_a, const char *name_b,
2430                             struct diff_filespec *one,
2431                             struct diff_filespec *two,
2432                             struct diffstat_t *diffstat,
2433                             struct diff_options *o,
2434                             struct diff_filepair *p)
2435{
2436        mmfile_t mf1, mf2;
2437        struct diffstat_file *data;
2438        int same_contents;
2439        int complete_rewrite = 0;
2440
2441        if (!DIFF_PAIR_UNMERGED(p)) {
2442                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2443                        complete_rewrite = 1;
2444        }
2445
2446        data = diffstat_add(diffstat, name_a, name_b);
2447        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2448
2449        if (!one || !two) {
2450                data->is_unmerged = 1;
2451                return;
2452        }
2453
2454        same_contents = !hashcmp(one->sha1, two->sha1);
2455
2456        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2457                data->is_binary = 1;
2458                if (same_contents) {
2459                        data->added = 0;
2460                        data->deleted = 0;
2461                } else {
2462                        data->added = diff_filespec_size(two);
2463                        data->deleted = diff_filespec_size(one);
2464                }
2465        }
2466
2467        else if (complete_rewrite) {
2468                diff_populate_filespec(one, 0);
2469                diff_populate_filespec(two, 0);
2470                data->deleted = count_lines(one->data, one->size);
2471                data->added = count_lines(two->data, two->size);
2472        }
2473
2474        else if (!same_contents) {
2475                /* Crazy xdl interfaces.. */
2476                xpparam_t xpp;
2477                xdemitconf_t xecfg;
2478
2479                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2480                        die("unable to read files to diff");
2481
2482                memset(&xpp, 0, sizeof(xpp));
2483                memset(&xecfg, 0, sizeof(xecfg));
2484                xpp.flags = o->xdl_opts;
2485                xecfg.ctxlen = o->context;
2486                xecfg.interhunkctxlen = o->interhunkcontext;
2487                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2488                              &xpp, &xecfg);
2489        }
2490
2491        diff_free_filespec_data(one);
2492        diff_free_filespec_data(two);
2493}
2494
2495static void builtin_checkdiff(const char *name_a, const char *name_b,
2496                              const char *attr_path,
2497                              struct diff_filespec *one,
2498                              struct diff_filespec *two,
2499                              struct diff_options *o)
2500{
2501        mmfile_t mf1, mf2;
2502        struct checkdiff_t data;
2503
2504        if (!two)
2505                return;
2506
2507        memset(&data, 0, sizeof(data));
2508        data.filename = name_b ? name_b : name_a;
2509        data.lineno = 0;
2510        data.o = o;
2511        data.ws_rule = whitespace_rule(attr_path);
2512        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2513
2514        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2515                die("unable to read files to diff");
2516
2517        /*
2518         * All the other codepaths check both sides, but not checking
2519         * the "old" side here is deliberate.  We are checking the newly
2520         * introduced changes, and as long as the "new" side is text, we
2521         * can and should check what it introduces.
2522         */
2523        if (diff_filespec_is_binary(two))
2524                goto free_and_return;
2525        else {
2526                /* Crazy xdl interfaces.. */
2527                xpparam_t xpp;
2528                xdemitconf_t xecfg;
2529
2530                memset(&xpp, 0, sizeof(xpp));
2531                memset(&xecfg, 0, sizeof(xecfg));
2532                xecfg.ctxlen = 1; /* at least one context line */
2533                xpp.flags = 0;
2534                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2535                              &xpp, &xecfg);
2536
2537                if (data.ws_rule & WS_BLANK_AT_EOF) {
2538                        struct emit_callback ecbdata;
2539                        int blank_at_eof;
2540
2541                        ecbdata.ws_rule = data.ws_rule;
2542                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2543                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2544
2545                        if (blank_at_eof) {
2546                                static char *err;
2547                                if (!err)
2548                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2549                                fprintf(o->file, "%s:%d: %s.\n",
2550                                        data.filename, blank_at_eof, err);
2551                                data.status = 1; /* report errors */
2552                        }
2553                }
2554        }
2555 free_and_return:
2556        diff_free_filespec_data(one);
2557        diff_free_filespec_data(two);
2558        if (data.status)
2559                DIFF_OPT_SET(o, CHECK_FAILED);
2560}
2561
2562struct diff_filespec *alloc_filespec(const char *path)
2563{
2564        int namelen = strlen(path);
2565        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2566
2567        memset(spec, 0, sizeof(*spec));
2568        spec->path = (char *)(spec + 1);
2569        memcpy(spec->path, path, namelen+1);
2570        spec->count = 1;
2571        spec->is_binary = -1;
2572        return spec;
2573}
2574
2575void free_filespec(struct diff_filespec *spec)
2576{
2577        if (!--spec->count) {
2578                diff_free_filespec_data(spec);
2579                free(spec);
2580        }
2581}
2582
2583void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2584                   int sha1_valid, unsigned short mode)
2585{
2586        if (mode) {
2587                spec->mode = canon_mode(mode);
2588                hashcpy(spec->sha1, sha1);
2589                spec->sha1_valid = sha1_valid;
2590        }
2591}
2592
2593/*
2594 * Given a name and sha1 pair, if the index tells us the file in
2595 * the work tree has that object contents, return true, so that
2596 * prepare_temp_file() does not have to inflate and extract.
2597 */
2598static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2599{
2600        const struct cache_entry *ce;
2601        struct stat st;
2602        int pos, len;
2603
2604        /*
2605         * We do not read the cache ourselves here, because the
2606         * benchmark with my previous version that always reads cache
2607         * shows that it makes things worse for diff-tree comparing
2608         * two linux-2.6 kernel trees in an already checked out work
2609         * tree.  This is because most diff-tree comparisons deal with
2610         * only a small number of files, while reading the cache is
2611         * expensive for a large project, and its cost outweighs the
2612         * savings we get by not inflating the object to a temporary
2613         * file.  Practically, this code only helps when we are used
2614         * by diff-cache --cached, which does read the cache before
2615         * calling us.
2616         */
2617        if (!active_cache)
2618                return 0;
2619
2620        /* We want to avoid the working directory if our caller
2621         * doesn't need the data in a normal file, this system
2622         * is rather slow with its stat/open/mmap/close syscalls,
2623         * and the object is contained in a pack file.  The pack
2624         * is probably already open and will be faster to obtain
2625         * the data through than the working directory.  Loose
2626         * objects however would tend to be slower as they need
2627         * to be individually opened and inflated.
2628         */
2629        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2630                return 0;
2631
2632        len = strlen(name);
2633        pos = cache_name_pos(name, len);
2634        if (pos < 0)
2635                return 0;
2636        ce = active_cache[pos];
2637
2638        /*
2639         * This is not the sha1 we are looking for, or
2640         * unreusable because it is not a regular file.
2641         */
2642        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2643                return 0;
2644
2645        /*
2646         * If ce is marked as "assume unchanged", there is no
2647         * guarantee that work tree matches what we are looking for.
2648         */
2649        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2650                return 0;
2651
2652        /*
2653         * If ce matches the file in the work tree, we can reuse it.
2654         */
2655        if (ce_uptodate(ce) ||
2656            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2657                return 1;
2658
2659        return 0;
2660}
2661
2662static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2663{
2664        int len;
2665        char *data = xmalloc(100), *dirty = "";
2666
2667        /* Are we looking at the work tree? */
2668        if (s->dirty_submodule)
2669                dirty = "-dirty";
2670
2671        len = snprintf(data, 100,
2672                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2673        s->data = data;
2674        s->size = len;
2675        s->should_free = 1;
2676        if (size_only) {
2677                s->data = NULL;
2678                free(data);
2679        }
2680        return 0;
2681}
2682
2683/*
2684 * While doing rename detection and pickaxe operation, we may need to
2685 * grab the data for the blob (or file) for our own in-core comparison.
2686 * diff_filespec has data and size fields for this purpose.
2687 */
2688int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2689{
2690        int size_only = flags & CHECK_SIZE_ONLY;
2691        int err = 0;
2692        /*
2693         * demote FAIL to WARN to allow inspecting the situation
2694         * instead of refusing.
2695         */
2696        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2697                                    ? SAFE_CRLF_WARN
2698                                    : safe_crlf);
2699
2700        if (!DIFF_FILE_VALID(s))
2701                die("internal error: asking to populate invalid file.");
2702        if (S_ISDIR(s->mode))
2703                return -1;
2704
2705        if (s->data)
2706                return 0;
2707
2708        if (size_only && 0 < s->size)
2709                return 0;
2710
2711        if (S_ISGITLINK(s->mode))
2712                return diff_populate_gitlink(s, size_only);
2713
2714        if (!s->sha1_valid ||
2715            reuse_worktree_file(s->path, s->sha1, 0)) {
2716                struct strbuf buf = STRBUF_INIT;
2717                struct stat st;
2718                int fd;
2719
2720                if (lstat(s->path, &st) < 0) {
2721                        if (errno == ENOENT) {
2722                        err_empty:
2723                                err = -1;
2724                        empty:
2725                                s->data = (char *)"";
2726                                s->size = 0;
2727                                return err;
2728                        }
2729                }
2730                s->size = xsize_t(st.st_size);
2731                if (!s->size)
2732                        goto empty;
2733                if (S_ISLNK(st.st_mode)) {
2734                        struct strbuf sb = STRBUF_INIT;
2735
2736                        if (strbuf_readlink(&sb, s->path, s->size))
2737                                goto err_empty;
2738                        s->size = sb.len;
2739                        s->data = strbuf_detach(&sb, NULL);
2740                        s->should_free = 1;
2741                        return 0;
2742                }
2743                if (size_only)
2744                        return 0;
2745                if ((flags & CHECK_BINARY) &&
2746                    s->size > big_file_threshold && s->is_binary == -1) {
2747                        s->is_binary = 1;
2748                        return 0;
2749                }
2750                fd = open(s->path, O_RDONLY);
2751                if (fd < 0)
2752                        goto err_empty;
2753                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2754                close(fd);
2755                s->should_munmap = 1;
2756
2757                /*
2758                 * Convert from working tree format to canonical git format
2759                 */
2760                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2761                        size_t size = 0;
2762                        munmap(s->data, s->size);
2763                        s->should_munmap = 0;
2764                        s->data = strbuf_detach(&buf, &size);
2765                        s->size = size;
2766                        s->should_free = 1;
2767                }
2768        }
2769        else {
2770                enum object_type type;
2771                if (size_only || (flags & CHECK_BINARY)) {
2772                        type = sha1_object_info(s->sha1, &s->size);
2773                        if (type < 0)
2774                                die("unable to read %s", sha1_to_hex(s->sha1));
2775                        if (size_only)
2776                                return 0;
2777                        if (s->size > big_file_threshold && s->is_binary == -1) {
2778                                s->is_binary = 1;
2779                                return 0;
2780                        }
2781                }
2782                s->data = read_sha1_file(s->sha1, &type, &s->size);
2783                if (!s->data)
2784                        die("unable to read %s", sha1_to_hex(s->sha1));
2785                s->should_free = 1;
2786        }
2787        return 0;
2788}
2789
2790void diff_free_filespec_blob(struct diff_filespec *s)
2791{
2792        if (s->should_free)
2793                free(s->data);
2794        else if (s->should_munmap)
2795                munmap(s->data, s->size);
2796
2797        if (s->should_free || s->should_munmap) {
2798                s->should_free = s->should_munmap = 0;
2799                s->data = NULL;
2800        }
2801}
2802
2803void diff_free_filespec_data(struct diff_filespec *s)
2804{
2805        diff_free_filespec_blob(s);
2806        free(s->cnt_data);
2807        s->cnt_data = NULL;
2808}
2809
2810static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2811                           void *blob,
2812                           unsigned long size,
2813                           const unsigned char *sha1,
2814                           int mode)
2815{
2816        int fd;
2817        struct strbuf buf = STRBUF_INIT;
2818        struct strbuf template = STRBUF_INIT;
2819        char *path_dup = xstrdup(path);
2820        const char *base = basename(path_dup);
2821
2822        /* Generate "XXXXXX_basename.ext" */
2823        strbuf_addstr(&template, "XXXXXX_");
2824        strbuf_addstr(&template, base);
2825
2826        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2827        if (fd < 0)
2828                die_errno("unable to create temp-file");
2829        if (convert_to_working_tree(path,
2830                        (const char *)blob, (size_t)size, &buf)) {
2831                blob = buf.buf;
2832                size = buf.len;
2833        }
2834        if (write_in_full(fd, blob, size) != size)
2835                die_errno("unable to write temp-file");
2836        close_tempfile(&temp->tempfile);
2837        temp->name = get_tempfile_path(&temp->tempfile);
2838        strcpy(temp->hex, sha1_to_hex(sha1));
2839        temp->hex[40] = 0;
2840        sprintf(temp->mode, "%06o", mode);
2841        strbuf_release(&buf);
2842        strbuf_release(&template);
2843        free(path_dup);
2844}
2845
2846static struct diff_tempfile *prepare_temp_file(const char *name,
2847                struct diff_filespec *one)
2848{
2849        struct diff_tempfile *temp = claim_diff_tempfile();
2850
2851        if (!DIFF_FILE_VALID(one)) {
2852        not_a_valid_file:
2853                /* A '-' entry produces this for file-2, and
2854                 * a '+' entry produces this for file-1.
2855                 */
2856                temp->name = "/dev/null";
2857                strcpy(temp->hex, ".");
2858                strcpy(temp->mode, ".");
2859                return temp;
2860        }
2861
2862        if (!S_ISGITLINK(one->mode) &&
2863            (!one->sha1_valid ||
2864             reuse_worktree_file(name, one->sha1, 1))) {
2865                struct stat st;
2866                if (lstat(name, &st) < 0) {
2867                        if (errno == ENOENT)
2868                                goto not_a_valid_file;
2869                        die_errno("stat(%s)", name);
2870                }
2871                if (S_ISLNK(st.st_mode)) {
2872                        struct strbuf sb = STRBUF_INIT;
2873                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2874                                die_errno("readlink(%s)", name);
2875                        prep_temp_blob(name, temp, sb.buf, sb.len,
2876                                       (one->sha1_valid ?
2877                                        one->sha1 : null_sha1),
2878                                       (one->sha1_valid ?
2879                                        one->mode : S_IFLNK));
2880                        strbuf_release(&sb);
2881                }
2882                else {
2883                        /* we can borrow from the file in the work tree */
2884                        temp->name = name;
2885                        if (!one->sha1_valid)
2886                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2887                        else
2888                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2889                        /* Even though we may sometimes borrow the
2890                         * contents from the work tree, we always want
2891                         * one->mode.  mode is trustworthy even when
2892                         * !(one->sha1_valid), as long as
2893                         * DIFF_FILE_VALID(one).
2894                         */
2895                        sprintf(temp->mode, "%06o", one->mode);
2896                }
2897                return temp;
2898        }
2899        else {
2900                if (diff_populate_filespec(one, 0))
2901                        die("cannot read data blob for %s", one->path);
2902                prep_temp_blob(name, temp, one->data, one->size,
2903                               one->sha1, one->mode);
2904        }
2905        return temp;
2906}
2907
2908static void add_external_diff_name(struct argv_array *argv,
2909                                   const char *name,
2910                                   struct diff_filespec *df)
2911{
2912        struct diff_tempfile *temp = prepare_temp_file(name, df);
2913        argv_array_push(argv, temp->name);
2914        argv_array_push(argv, temp->hex);
2915        argv_array_push(argv, temp->mode);
2916}
2917
2918/* An external diff command takes:
2919 *
2920 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2921 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2922 *
2923 */
2924static void run_external_diff(const char *pgm,
2925                              const char *name,
2926                              const char *other,
2927                              struct diff_filespec *one,
2928                              struct diff_filespec *two,
2929                              const char *xfrm_msg,
2930                              int complete_rewrite,
2931                              struct diff_options *o)
2932{
2933        struct argv_array argv = ARGV_ARRAY_INIT;
2934        struct argv_array env = ARGV_ARRAY_INIT;
2935        struct diff_queue_struct *q = &diff_queued_diff;
2936
2937        argv_array_push(&argv, pgm);
2938        argv_array_push(&argv, name);
2939
2940        if (one && two) {
2941                add_external_diff_name(&argv, name, one);
2942                if (!other)
2943                        add_external_diff_name(&argv, name, two);
2944                else {
2945                        add_external_diff_name(&argv, other, two);
2946                        argv_array_push(&argv, other);
2947                        argv_array_push(&argv, xfrm_msg);
2948                }
2949        }
2950
2951        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2952        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2953
2954        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2955                die(_("external diff died, stopping at %s"), name);
2956
2957        remove_tempfile();
2958        argv_array_clear(&argv);
2959        argv_array_clear(&env);
2960}
2961
2962static int similarity_index(struct diff_filepair *p)
2963{
2964        return p->score * 100 / MAX_SCORE;
2965}
2966
2967static void fill_metainfo(struct strbuf *msg,
2968                          const char *name,
2969                          const char *other,
2970                          struct diff_filespec *one,
2971                          struct diff_filespec *two,
2972                          struct diff_options *o,
2973                          struct diff_filepair *p,
2974                          int *must_show_header,
2975                          int use_color)
2976{
2977        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2978        const char *reset = diff_get_color(use_color, DIFF_RESET);
2979        const char *line_prefix = diff_line_prefix(o);
2980
2981        *must_show_header = 1;
2982        strbuf_init(msg, PATH_MAX * 2 + 300);
2983        switch (p->status) {
2984        case DIFF_STATUS_COPIED:
2985                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2986                            line_prefix, set, similarity_index(p));
2987                strbuf_addf(msg, "%s\n%s%scopy from ",
2988                            reset,  line_prefix, set);
2989                quote_c_style(name, msg, NULL, 0);
2990                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2991                quote_c_style(other, msg, NULL, 0);
2992                strbuf_addf(msg, "%s\n", reset);
2993                break;
2994        case DIFF_STATUS_RENAMED:
2995                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2996                            line_prefix, set, similarity_index(p));
2997                strbuf_addf(msg, "%s\n%s%srename from ",
2998                            reset, line_prefix, set);
2999                quote_c_style(name, msg, NULL, 0);
3000                strbuf_addf(msg, "%s\n%s%srename to ",
3001                            reset, line_prefix, set);
3002                quote_c_style(other, msg, NULL, 0);
3003                strbuf_addf(msg, "%s\n", reset);
3004                break;
3005        case DIFF_STATUS_MODIFIED:
3006                if (p->score) {
3007                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3008                                    line_prefix,
3009                                    set, similarity_index(p), reset);
3010                        break;
3011                }
3012                /* fallthru */
3013        default:
3014                *must_show_header = 0;
3015        }
3016        if (one && two && hashcmp(one->sha1, two->sha1)) {
3017                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3018
3019                if (DIFF_OPT_TST(o, BINARY)) {
3020                        mmfile_t mf;
3021                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3022                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3023                                abbrev = 40;
3024                }
3025                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3026                            find_unique_abbrev(one->sha1, abbrev));
3027                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3028                if (one->mode == two->mode)
3029                        strbuf_addf(msg, " %06o", one->mode);
3030                strbuf_addf(msg, "%s\n", reset);
3031        }
3032}
3033
3034static void run_diff_cmd(const char *pgm,
3035                         const char *name,
3036                         const char *other,
3037                         const char *attr_path,
3038                         struct diff_filespec *one,
3039                         struct diff_filespec *two,
3040                         struct strbuf *msg,
3041                         struct diff_options *o,
3042                         struct diff_filepair *p)
3043{
3044        const char *xfrm_msg = NULL;
3045        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3046        int must_show_header = 0;
3047
3048
3049        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3050                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3051                if (drv && drv->external)
3052                        pgm = drv->external;
3053        }
3054
3055        if (msg) {
3056                /*
3057                 * don't use colors when the header is intended for an
3058                 * external diff driver
3059                 */
3060                fill_metainfo(msg, name, other, one, two, o, p,
3061                              &must_show_header,
3062                              want_color(o->use_color) && !pgm);
3063                xfrm_msg = msg->len ? msg->buf : NULL;
3064        }
3065
3066        if (pgm) {
3067                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3068                                  complete_rewrite, o);
3069                return;
3070        }
3071        if (one && two)
3072                builtin_diff(name, other ? other : name,
3073                             one, two, xfrm_msg, must_show_header,
3074                             o, complete_rewrite);
3075        else
3076                fprintf(o->file, "* Unmerged path %s\n", name);
3077}
3078
3079static void diff_fill_sha1_info(struct diff_filespec *one)
3080{
3081        if (DIFF_FILE_VALID(one)) {
3082                if (!one->sha1_valid) {
3083                        struct stat st;
3084                        if (one->is_stdin) {
3085                                hashcpy(one->sha1, null_sha1);
3086                                return;
3087                        }
3088                        if (lstat(one->path, &st) < 0)
3089                                die_errno("stat '%s'", one->path);
3090                        if (index_path(one->sha1, one->path, &st, 0))
3091                                die("cannot hash %s", one->path);
3092                }
3093        }
3094        else
3095                hashclr(one->sha1);
3096}
3097
3098static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3099{
3100        /* Strip the prefix but do not molest /dev/null and absolute paths */
3101        if (*namep && **namep != '/') {
3102                *namep += prefix_length;
3103                if (**namep == '/')
3104                        ++*namep;
3105        }
3106        if (*otherp && **otherp != '/') {
3107                *otherp += prefix_length;
3108                if (**otherp == '/')
3109                        ++*otherp;
3110        }
3111}
3112
3113static void run_diff(struct diff_filepair *p, struct diff_options *o)
3114{
3115        const char *pgm = external_diff();
3116        struct strbuf msg;
3117        struct diff_filespec *one = p->one;
3118        struct diff_filespec *two = p->two;
3119        const char *name;
3120        const char *other;
3121        const char *attr_path;
3122
3123        name  = p->one->path;
3124        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3125        attr_path = name;
3126        if (o->prefix_length)
3127                strip_prefix(o->prefix_length, &name, &other);
3128
3129        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3130                pgm = NULL;
3131
3132        if (DIFF_PAIR_UNMERGED(p)) {
3133                run_diff_cmd(pgm, name, NULL, attr_path,
3134                             NULL, NULL, NULL, o, p);
3135                return;
3136        }
3137
3138        diff_fill_sha1_info(one);
3139        diff_fill_sha1_info(two);
3140
3141        if (!pgm &&
3142            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3143            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3144                /*
3145                 * a filepair that changes between file and symlink
3146                 * needs to be split into deletion and creation.
3147                 */
3148                struct diff_filespec *null = alloc_filespec(two->path);
3149                run_diff_cmd(NULL, name, other, attr_path,
3150                             one, null, &msg, o, p);
3151                free(null);
3152                strbuf_release(&msg);
3153
3154                null = alloc_filespec(one->path);
3155                run_diff_cmd(NULL, name, other, attr_path,
3156                             null, two, &msg, o, p);
3157                free(null);
3158        }
3159        else
3160                run_diff_cmd(pgm, name, other, attr_path,
3161                             one, two, &msg, o, p);
3162
3163        strbuf_release(&msg);
3164}
3165
3166static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3167                         struct diffstat_t *diffstat)
3168{
3169        const char *name;
3170        const char *other;
3171
3172        if (DIFF_PAIR_UNMERGED(p)) {
3173                /* unmerged */
3174                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3175                return;
3176        }
3177
3178        name = p->one->path;
3179        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3180
3181        if (o->prefix_length)
3182                strip_prefix(o->prefix_length, &name, &other);
3183
3184        diff_fill_sha1_info(p->one);
3185        diff_fill_sha1_info(p->two);
3186
3187        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3188}
3189
3190static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3191{
3192        const char *name;
3193        const char *other;
3194        const char *attr_path;
3195
3196        if (DIFF_PAIR_UNMERGED(p)) {
3197                /* unmerged */
3198                return;
3199        }
3200
3201        name = p->one->path;
3202        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3203        attr_path = other ? other : name;
3204
3205        if (o->prefix_length)
3206                strip_prefix(o->prefix_length, &name, &other);
3207
3208        diff_fill_sha1_info(p->one);
3209        diff_fill_sha1_info(p->two);
3210
3211        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3212}
3213
3214void diff_setup(struct diff_options *options)
3215{
3216        memcpy(options, &default_diff_options, sizeof(*options));
3217
3218        options->file = stdout;
3219
3220        options->line_termination = '\n';
3221        options->break_opt = -1;
3222        options->rename_limit = -1;
3223        options->dirstat_permille = diff_dirstat_permille_default;
3224        options->context = diff_context_default;
3225        DIFF_OPT_SET(options, RENAME_EMPTY);
3226
3227        /* pathchange left =NULL by default */
3228        options->change = diff_change;
3229        options->add_remove = diff_addremove;
3230        options->use_color = diff_use_color_default;
3231        options->detect_rename = diff_detect_rename_default;
3232        options->xdl_opts |= diff_algorithm;
3233
3234        options->orderfile = diff_order_file_cfg;
3235
3236        if (diff_no_prefix) {
3237                options->a_prefix = options->b_prefix = "";
3238        } else if (!diff_mnemonic_prefix) {
3239                options->a_prefix = "a/";
3240                options->b_prefix = "b/";
3241        }
3242}
3243
3244void diff_setup_done(struct diff_options *options)
3245{
3246        int count = 0;
3247
3248        if (options->set_default)
3249                options->set_default(options);
3250
3251        if (options->output_format & DIFF_FORMAT_NAME)
3252                count++;
3253        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3254                count++;
3255        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3256                count++;
3257        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3258                count++;
3259        if (count > 1)
3260                die("--name-only, --name-status, --check and -s are mutually exclusive");
3261
3262        /*
3263         * Most of the time we can say "there are changes"
3264         * only by checking if there are changed paths, but
3265         * --ignore-whitespace* options force us to look
3266         * inside contents.
3267         */
3268
3269        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3270            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3271            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3272                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3273        else
3274                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3275
3276        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3277                options->detect_rename = DIFF_DETECT_COPY;
3278
3279        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3280                options->prefix = NULL;
3281        if (options->prefix)
3282                options->prefix_length = strlen(options->prefix);
3283        else
3284                options->prefix_length = 0;
3285
3286        if (options->output_format & (DIFF_FORMAT_NAME |
3287                                      DIFF_FORMAT_NAME_STATUS |
3288                                      DIFF_FORMAT_CHECKDIFF |
3289                                      DIFF_FORMAT_NO_OUTPUT))
3290                options->output_format &= ~(DIFF_FORMAT_RAW |
3291                                            DIFF_FORMAT_NUMSTAT |
3292                                            DIFF_FORMAT_DIFFSTAT |
3293                                            DIFF_FORMAT_SHORTSTAT |
3294                                            DIFF_FORMAT_DIRSTAT |
3295                                            DIFF_FORMAT_SUMMARY |
3296                                            DIFF_FORMAT_PATCH);
3297
3298        /*
3299         * These cases always need recursive; we do not drop caller-supplied
3300         * recursive bits for other formats here.
3301         */
3302        if (options->output_format & (DIFF_FORMAT_PATCH |
3303                                      DIFF_FORMAT_NUMSTAT |
3304                                      DIFF_FORMAT_DIFFSTAT |
3305                                      DIFF_FORMAT_SHORTSTAT |
3306                                      DIFF_FORMAT_DIRSTAT |
3307                                      DIFF_FORMAT_SUMMARY |
3308                                      DIFF_FORMAT_CHECKDIFF))
3309                DIFF_OPT_SET(options, RECURSIVE);
3310        /*
3311         * Also pickaxe would not work very well if you do not say recursive
3312         */
3313        if (options->pickaxe)
3314                DIFF_OPT_SET(options, RECURSIVE);
3315        /*
3316         * When patches are generated, submodules diffed against the work tree
3317         * must be checked for dirtiness too so it can be shown in the output
3318         */
3319        if (options->output_format & DIFF_FORMAT_PATCH)
3320                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3321
3322        if (options->detect_rename && options->rename_limit < 0)
3323                options->rename_limit = diff_rename_limit_default;
3324        if (options->setup & DIFF_SETUP_USE_CACHE) {
3325                if (!active_cache)
3326                        /* read-cache does not die even when it fails
3327                         * so it is safe for us to do this here.  Also
3328                         * it does not smudge active_cache or active_nr
3329                         * when it fails, so we do not have to worry about
3330                         * cleaning it up ourselves either.
3331                         */
3332                        read_cache();
3333        }
3334        if (options->abbrev <= 0 || 40 < options->abbrev)
3335                options->abbrev = 40; /* full */
3336
3337        /*
3338         * It does not make sense to show the first hit we happened
3339         * to have found.  It does not make sense not to return with
3340         * exit code in such a case either.
3341         */
3342        if (DIFF_OPT_TST(options, QUICK)) {
3343                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3344                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3345        }
3346
3347        options->diff_path_counter = 0;
3348
3349        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3350                die(_("--follow requires exactly one pathspec"));
3351}
3352
3353static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3354{
3355        char c, *eq;
3356        int len;
3357
3358        if (*arg != '-')
3359                return 0;
3360        c = *++arg;
3361        if (!c)
3362                return 0;
3363        if (c == arg_short) {
3364                c = *++arg;
3365                if (!c)
3366                        return 1;
3367                if (val && isdigit(c)) {
3368                        char *end;
3369                        int n = strtoul(arg, &end, 10);
3370                        if (*end)
3371                                return 0;
3372                        *val = n;
3373                        return 1;
3374                }
3375                return 0;
3376        }
3377        if (c != '-')
3378                return 0;
3379        arg++;
3380        eq = strchrnul(arg, '=');
3381        len = eq - arg;
3382        if (!len || strncmp(arg, arg_long, len))
3383                return 0;
3384        if (*eq) {
3385                int n;
3386                char *end;
3387                if (!isdigit(*++eq))
3388                        return 0;
3389                n = strtoul(eq, &end, 10);
3390                if (*end)
3391                        return 0;
3392                *val = n;
3393        }
3394        return 1;
3395}
3396
3397static int diff_scoreopt_parse(const char *opt);
3398
3399static inline int short_opt(char opt, const char **argv,
3400                            const char **optarg)
3401{
3402        const char *arg = argv[0];
3403        if (arg[0] != '-' || arg[1] != opt)
3404                return 0;
3405        if (arg[2] != '\0') {
3406                *optarg = arg + 2;
3407                return 1;
3408        }
3409        if (!argv[1])
3410                die("Option '%c' requires a value", opt);
3411        *optarg = argv[1];
3412        return 2;
3413}
3414
3415int parse_long_opt(const char *opt, const char **argv,
3416                   const char **optarg)
3417{
3418        const char *arg = argv[0];
3419        if (!skip_prefix(arg, "--", &arg))
3420                return 0;
3421        if (!skip_prefix(arg, opt, &arg))
3422                return 0;
3423        if (*arg == '=') { /* stuck form: --option=value */
3424                *optarg = arg + 1;
3425                return 1;
3426        }
3427        if (*arg != '\0')
3428                return 0;
3429        /* separate form: --option value */
3430        if (!argv[1])
3431                die("Option '--%s' requires a value", opt);
3432        *optarg = argv[1];
3433        return 2;
3434}
3435
3436static int stat_opt(struct diff_options *options, const char **av)
3437{
3438        const char *arg = av[0];
3439        char *end;
3440        int width = options->stat_width;
3441        int name_width = options->stat_name_width;
3442        int graph_width = options->stat_graph_width;
3443        int count = options->stat_count;
3444        int argcount = 1;
3445
3446        if (!skip_prefix(arg, "--stat", &arg))
3447                die("BUG: stat option does not begin with --stat: %s", arg);
3448        end = (char *)arg;
3449
3450        switch (*arg) {
3451        case '-':
3452                if (skip_prefix(arg, "-width", &arg)) {
3453                        if (*arg == '=')
3454                                width = strtoul(arg + 1, &end, 10);
3455                        else if (!*arg && !av[1])
3456                                die("Option '--stat-width' requires a value");
3457                        else if (!*arg) {
3458                                width = strtoul(av[1], &end, 10);
3459                                argcount = 2;
3460                        }
3461                } else if (skip_prefix(arg, "-name-width", &arg)) {
3462                        if (*arg == '=')
3463                                name_width = strtoul(arg + 1, &end, 10);
3464                        else if (!*arg && !av[1])
3465                                die("Option '--stat-name-width' requires a value");
3466                        else if (!*arg) {
3467                                name_width = strtoul(av[1], &end, 10);
3468                                argcount = 2;
3469                        }
3470                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3471                        if (*arg == '=')
3472                                graph_width = strtoul(arg + 1, &end, 10);
3473                        else if (!*arg && !av[1])
3474                                die("Option '--stat-graph-width' requires a value");
3475                        else if (!*arg) {
3476                                graph_width = strtoul(av[1], &end, 10);
3477                                argcount = 2;
3478                        }
3479                } else if (skip_prefix(arg, "-count", &arg)) {
3480                        if (*arg == '=')
3481                                count = strtoul(arg + 1, &end, 10);
3482                        else if (!*arg && !av[1])
3483                                die("Option '--stat-count' requires a value");
3484                        else if (!*arg) {
3485                                count = strtoul(av[1], &end, 10);
3486                                argcount = 2;
3487                        }
3488                }
3489                break;
3490        case '=':
3491                width = strtoul(arg+1, &end, 10);
3492                if (*end == ',')
3493                        name_width = strtoul(end+1, &end, 10);
3494                if (*end == ',')
3495                        count = strtoul(end+1, &end, 10);
3496        }
3497
3498        /* Important! This checks all the error cases! */
3499        if (*end)
3500                return 0;
3501        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3502        options->stat_name_width = name_width;
3503        options->stat_graph_width = graph_width;
3504        options->stat_width = width;
3505        options->stat_count = count;
3506        return argcount;
3507}
3508
3509static int parse_dirstat_opt(struct diff_options *options, const char *params)
3510{
3511        struct strbuf errmsg = STRBUF_INIT;
3512        if (parse_dirstat_params(options, params, &errmsg))
3513                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3514                    errmsg.buf);
3515        strbuf_release(&errmsg);
3516        /*
3517         * The caller knows a dirstat-related option is given from the command
3518         * line; allow it to say "return this_function();"
3519         */
3520        options->output_format |= DIFF_FORMAT_DIRSTAT;
3521        return 1;
3522}
3523
3524static int parse_submodule_opt(struct diff_options *options, const char *value)
3525{
3526        if (parse_submodule_params(options, value))
3527                die(_("Failed to parse --submodule option parameter: '%s'"),
3528                        value);
3529        return 1;
3530}
3531
3532static const char diff_status_letters[] = {
3533        DIFF_STATUS_ADDED,
3534        DIFF_STATUS_COPIED,
3535        DIFF_STATUS_DELETED,
3536        DIFF_STATUS_MODIFIED,
3537        DIFF_STATUS_RENAMED,
3538        DIFF_STATUS_TYPE_CHANGED,
3539        DIFF_STATUS_UNKNOWN,
3540        DIFF_STATUS_UNMERGED,
3541        DIFF_STATUS_FILTER_AON,
3542        DIFF_STATUS_FILTER_BROKEN,
3543        '\0',
3544};
3545
3546static unsigned int filter_bit['Z' + 1];
3547
3548static void prepare_filter_bits(void)
3549{
3550        int i;
3551
3552        if (!filter_bit[DIFF_STATUS_ADDED]) {
3553                for (i = 0; diff_status_letters[i]; i++)
3554                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3555        }
3556}
3557
3558static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3559{
3560        return opt->filter & filter_bit[(int) status];
3561}
3562
3563static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3564{
3565        int i, optch;
3566
3567        prepare_filter_bits();
3568
3569        /*
3570         * If there is a negation e.g. 'd' in the input, and we haven't
3571         * initialized the filter field with another --diff-filter, start
3572         * from full set of bits, except for AON.
3573         */
3574        if (!opt->filter) {
3575                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3576                        if (optch < 'a' || 'z' < optch)
3577                                continue;
3578                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3579                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3580                        break;
3581                }
3582        }
3583
3584        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3585                unsigned int bit;
3586                int negate;
3587
3588                if ('a' <= optch && optch <= 'z') {
3589                        negate = 1;
3590                        optch = toupper(optch);
3591                } else {
3592                        negate = 0;
3593                }
3594
3595                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3596                if (!bit)
3597                        return optarg[i];
3598                if (negate)
3599                        opt->filter &= ~bit;
3600                else
3601                        opt->filter |= bit;
3602        }
3603        return 0;
3604}
3605
3606static void enable_patch_output(int *fmt) {
3607        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3608        *fmt |= DIFF_FORMAT_PATCH;
3609}
3610
3611int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3612{
3613        const char *arg = av[0];
3614        const char *optarg;
3615        int argcount;
3616
3617        /* Output format options */
3618        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3619            || opt_arg(arg, 'U', "unified", &options->context))
3620                enable_patch_output(&options->output_format);
3621        else if (!strcmp(arg, "--raw"))
3622                options->output_format |= DIFF_FORMAT_RAW;
3623        else if (!strcmp(arg, "--patch-with-raw")) {
3624                enable_patch_output(&options->output_format);
3625                options->output_format |= DIFF_FORMAT_RAW;
3626        } else if (!strcmp(arg, "--numstat"))
3627                options->output_format |= DIFF_FORMAT_NUMSTAT;
3628        else if (!strcmp(arg, "--shortstat"))
3629                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3630        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3631                return parse_dirstat_opt(options, "");
3632        else if (skip_prefix(arg, "-X", &arg))
3633                return parse_dirstat_opt(options, arg);
3634        else if (skip_prefix(arg, "--dirstat=", &arg))
3635                return parse_dirstat_opt(options, arg);
3636        else if (!strcmp(arg, "--cumulative"))
3637                return parse_dirstat_opt(options, "cumulative");
3638        else if (!strcmp(arg, "--dirstat-by-file"))
3639                return parse_dirstat_opt(options, "files");
3640        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3641                parse_dirstat_opt(options, "files");
3642                return parse_dirstat_opt(options, arg);
3643        }
3644        else if (!strcmp(arg, "--check"))
3645                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3646        else if (!strcmp(arg, "--summary"))
3647                options->output_format |= DIFF_FORMAT_SUMMARY;
3648        else if (!strcmp(arg, "--patch-with-stat")) {
3649                enable_patch_output(&options->output_format);
3650                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3651        } else if (!strcmp(arg, "--name-only"))
3652                options->output_format |= DIFF_FORMAT_NAME;
3653        else if (!strcmp(arg, "--name-status"))
3654                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3655        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3656                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3657        else if (starts_with(arg, "--stat"))
3658                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3659                return stat_opt(options, av);
3660
3661        /* renames options */
3662        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3663                 !strcmp(arg, "--break-rewrites")) {
3664                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3665                        return error("invalid argument to -B: %s", arg+2);
3666        }
3667        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3668                 !strcmp(arg, "--find-renames")) {
3669                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3670                        return error("invalid argument to -M: %s", arg+2);
3671                options->detect_rename = DIFF_DETECT_RENAME;
3672        }
3673        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3674                options->irreversible_delete = 1;
3675        }
3676        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3677                 !strcmp(arg, "--find-copies")) {
3678                if (options->detect_rename == DIFF_DETECT_COPY)
3679                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3680                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3681                        return error("invalid argument to -C: %s", arg+2);
3682                options->detect_rename = DIFF_DETECT_COPY;
3683        }
3684        else if (!strcmp(arg, "--no-renames"))
3685                options->detect_rename = 0;
3686        else if (!strcmp(arg, "--rename-empty"))
3687                DIFF_OPT_SET(options, RENAME_EMPTY);
3688        else if (!strcmp(arg, "--no-rename-empty"))
3689                DIFF_OPT_CLR(options, RENAME_EMPTY);
3690        else if (!strcmp(arg, "--relative"))
3691                DIFF_OPT_SET(options, RELATIVE_NAME);
3692        else if (skip_prefix(arg, "--relative=", &arg)) {
3693                DIFF_OPT_SET(options, RELATIVE_NAME);
3694                options->prefix = arg;
3695        }
3696
3697        /* xdiff options */
3698        else if (!strcmp(arg, "--minimal"))
3699                DIFF_XDL_SET(options, NEED_MINIMAL);
3700        else if (!strcmp(arg, "--no-minimal"))
3701                DIFF_XDL_CLR(options, NEED_MINIMAL);
3702        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3703                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3704        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3705                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3706        else if (!strcmp(arg, "--ignore-space-at-eol"))
3707                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3708        else if (!strcmp(arg, "--ignore-blank-lines"))
3709                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3710        else if (!strcmp(arg, "--patience"))
3711                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3712        else if (!strcmp(arg, "--histogram"))
3713                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3714        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3715                long value = parse_algorithm_value(optarg);
3716                if (value < 0)
3717                        return error("option diff-algorithm accepts \"myers\", "
3718                                     "\"minimal\", \"patience\" and \"histogram\"");
3719                /* clear out previous settings */
3720                DIFF_XDL_CLR(options, NEED_MINIMAL);
3721                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3722                options->xdl_opts |= value;
3723                return argcount;
3724        }
3725
3726        /* flags options */
3727        else if (!strcmp(arg, "--binary")) {
3728                enable_patch_output(&options->output_format);
3729                DIFF_OPT_SET(options, BINARY);
3730        }
3731        else if (!strcmp(arg, "--full-index"))
3732                DIFF_OPT_SET(options, FULL_INDEX);
3733        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3734                DIFF_OPT_SET(options, TEXT);
3735        else if (!strcmp(arg, "-R"))
3736                DIFF_OPT_SET(options, REVERSE_DIFF);
3737        else if (!strcmp(arg, "--find-copies-harder"))
3738                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3739        else if (!strcmp(arg, "--follow"))
3740                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3741        else if (!strcmp(arg, "--no-follow"))
3742                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3743        else if (!strcmp(arg, "--color"))
3744                options->use_color = 1;
3745        else if (skip_prefix(arg, "--color=", &arg)) {
3746                int value = git_config_colorbool(NULL, arg);
3747                if (value < 0)
3748                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3749                options->use_color = value;
3750        }
3751        else if (!strcmp(arg, "--no-color"))
3752                options->use_color = 0;
3753        else if (!strcmp(arg, "--color-words")) {
3754                options->use_color = 1;
3755                options->word_diff = DIFF_WORDS_COLOR;
3756        }
3757        else if (skip_prefix(arg, "--color-words=", &arg)) {
3758                options->use_color = 1;
3759                options->word_diff = DIFF_WORDS_COLOR;
3760                options->word_regex = arg;
3761        }
3762        else if (!strcmp(arg, "--word-diff")) {
3763                if (options->word_diff == DIFF_WORDS_NONE)
3764                        options->word_diff = DIFF_WORDS_PLAIN;
3765        }
3766        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3767                if (!strcmp(arg, "plain"))
3768                        options->word_diff = DIFF_WORDS_PLAIN;
3769                else if (!strcmp(arg, "color")) {
3770                        options->use_color = 1;
3771                        options->word_diff = DIFF_WORDS_COLOR;
3772                }
3773                else if (!strcmp(arg, "porcelain"))
3774                        options->word_diff = DIFF_WORDS_PORCELAIN;
3775                else if (!strcmp(arg, "none"))
3776                        options->word_diff = DIFF_WORDS_NONE;
3777                else
3778                        die("bad --word-diff argument: %s", arg);
3779        }
3780        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3781                if (options->word_diff == DIFF_WORDS_NONE)
3782                        options->word_diff = DIFF_WORDS_PLAIN;
3783                options->word_regex = optarg;
3784                return argcount;
3785        }
3786        else if (!strcmp(arg, "--exit-code"))
3787                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3788        else if (!strcmp(arg, "--quiet"))
3789                DIFF_OPT_SET(options, QUICK);
3790        else if (!strcmp(arg, "--ext-diff"))
3791                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3792        else if (!strcmp(arg, "--no-ext-diff"))
3793                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3794        else if (!strcmp(arg, "--textconv"))
3795                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3796        else if (!strcmp(arg, "--no-textconv"))
3797                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3798        else if (!strcmp(arg, "--ignore-submodules")) {
3799                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3800                handle_ignore_submodules_arg(options, "all");
3801        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3802                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3803                handle_ignore_submodules_arg(options, arg);
3804        } else if (!strcmp(arg, "--submodule"))
3805                DIFF_OPT_SET(options, SUBMODULE_LOG);
3806        else if (skip_prefix(arg, "--submodule=", &arg))
3807                return parse_submodule_opt(options, arg);
3808
3809        /* misc options */
3810        else if (!strcmp(arg, "-z"))
3811                options->line_termination = 0;
3812        else if ((argcount = short_opt('l', av, &optarg))) {
3813                options->rename_limit = strtoul(optarg, NULL, 10);
3814                return argcount;
3815        }
3816        else if ((argcount = short_opt('S', av, &optarg))) {
3817                options->pickaxe = optarg;
3818                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3819                return argcount;
3820        } else if ((argcount = short_opt('G', av, &optarg))) {
3821                options->pickaxe = optarg;
3822                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3823                return argcount;
3824        }
3825        else if (!strcmp(arg, "--pickaxe-all"))
3826                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3827        else if (!strcmp(arg, "--pickaxe-regex"))
3828                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3829        else if ((argcount = short_opt('O', av, &optarg))) {
3830                options->orderfile = optarg;
3831                return argcount;
3832        }
3833        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3834                int offending = parse_diff_filter_opt(optarg, options);
3835                if (offending)
3836                        die("unknown change class '%c' in --diff-filter=%s",
3837                            offending, optarg);
3838                return argcount;
3839        }
3840        else if (!strcmp(arg, "--abbrev"))
3841                options->abbrev = DEFAULT_ABBREV;
3842        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3843                options->abbrev = strtoul(arg, NULL, 10);
3844                if (options->abbrev < MINIMUM_ABBREV)
3845                        options->abbrev = MINIMUM_ABBREV;
3846                else if (40 < options->abbrev)
3847                        options->abbrev = 40;
3848        }
3849        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3850                options->a_prefix = optarg;
3851                return argcount;
3852        }
3853        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3854                options->b_prefix = optarg;
3855                return argcount;
3856        }
3857        else if (!strcmp(arg, "--no-prefix"))
3858                options->a_prefix = options->b_prefix = "";
3859        else if (opt_arg(arg, '\0', "inter-hunk-context",
3860                         &options->interhunkcontext))
3861                ;
3862        else if (!strcmp(arg, "-W"))
3863                DIFF_OPT_SET(options, FUNCCONTEXT);
3864        else if (!strcmp(arg, "--function-context"))
3865                DIFF_OPT_SET(options, FUNCCONTEXT);
3866        else if (!strcmp(arg, "--no-function-context"))
3867                DIFF_OPT_CLR(options, FUNCCONTEXT);
3868        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3869                options->file = fopen(optarg, "w");
3870                if (!options->file)
3871                        die_errno("Could not open '%s'", optarg);
3872                options->close_file = 1;
3873                return argcount;
3874        } else
3875                return 0;
3876        return 1;
3877}
3878
3879int parse_rename_score(const char **cp_p)
3880{
3881        unsigned long num, scale;
3882        int ch, dot;
3883        const char *cp = *cp_p;
3884
3885        num = 0;
3886        scale = 1;
3887        dot = 0;
3888        for (;;) {
3889                ch = *cp;
3890                if ( !dot && ch == '.' ) {
3891                        scale = 1;
3892                        dot = 1;
3893                } else if ( ch == '%' ) {
3894                        scale = dot ? scale*100 : 100;
3895                        cp++;   /* % is always at the end */
3896                        break;
3897                } else if ( ch >= '0' && ch <= '9' ) {
3898                        if ( scale < 100000 ) {
3899                                scale *= 10;
3900                                num = (num*10) + (ch-'0');
3901                        }
3902                } else {
3903                        break;
3904                }
3905                cp++;
3906        }
3907        *cp_p = cp;
3908
3909        /* user says num divided by scale and we say internally that
3910         * is MAX_SCORE * num / scale.
3911         */
3912        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3913}
3914
3915static int diff_scoreopt_parse(const char *opt)
3916{
3917        int opt1, opt2, cmd;
3918
3919        if (*opt++ != '-')
3920                return -1;
3921        cmd = *opt++;
3922        if (cmd == '-') {
3923                /* convert the long-form arguments into short-form versions */
3924                if (skip_prefix(opt, "break-rewrites", &opt)) {
3925                        if (*opt == 0 || *opt++ == '=')
3926                                cmd = 'B';
3927                } else if (skip_prefix(opt, "find-copies", &opt)) {
3928                        if (*opt == 0 || *opt++ == '=')
3929                                cmd = 'C';
3930                } else if (skip_prefix(opt, "find-renames", &opt)) {
3931                        if (*opt == 0 || *opt++ == '=')
3932                                cmd = 'M';
3933                }
3934        }
3935        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3936                return -1; /* that is not a -M, -C, or -B option */
3937
3938        opt1 = parse_rename_score(&opt);
3939        if (cmd != 'B')
3940                opt2 = 0;
3941        else {
3942                if (*opt == 0)
3943                        opt2 = 0;
3944                else if (*opt != '/')
3945                        return -1; /* we expect -B80/99 or -B80 */
3946                else {
3947                        opt++;
3948                        opt2 = parse_rename_score(&opt);
3949                }
3950        }
3951        if (*opt != 0)
3952                return -1;
3953        return opt1 | (opt2 << 16);
3954}
3955
3956struct diff_queue_struct diff_queued_diff;
3957
3958void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3959{
3960        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
3961        queue->queue[queue->nr++] = dp;
3962}
3963
3964struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3965                                 struct diff_filespec *one,
3966                                 struct diff_filespec *two)
3967{
3968        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3969        dp->one = one;
3970        dp->two = two;
3971        if (queue)
3972                diff_q(queue, dp);
3973        return dp;
3974}
3975
3976void diff_free_filepair(struct diff_filepair *p)
3977{
3978        free_filespec(p->one);
3979        free_filespec(p->two);
3980        free(p);
3981}
3982
3983/* This is different from find_unique_abbrev() in that
3984 * it stuffs the result with dots for alignment.
3985 */
3986const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3987{
3988        int abblen;
3989        const char *abbrev;
3990        if (len == 40)
3991                return sha1_to_hex(sha1);
3992
3993        abbrev = find_unique_abbrev(sha1, len);
3994        abblen = strlen(abbrev);
3995        if (abblen < 37) {
3996                static char hex[41];
3997                if (len < abblen && abblen <= len + 2)
3998                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3999                else
4000                        sprintf(hex, "%s...", abbrev);
4001                return hex;
4002        }
4003        return sha1_to_hex(sha1);
4004}
4005
4006static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4007{
4008        int line_termination = opt->line_termination;
4009        int inter_name_termination = line_termination ? '\t' : '\0';
4010
4011        fprintf(opt->file, "%s", diff_line_prefix(opt));
4012        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4013                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4014                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4015                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4016        }
4017        if (p->score) {
4018                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4019                        inter_name_termination);
4020        } else {
4021                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4022        }
4023
4024        if (p->status == DIFF_STATUS_COPIED ||
4025            p->status == DIFF_STATUS_RENAMED) {
4026                const char *name_a, *name_b;
4027                name_a = p->one->path;
4028                name_b = p->two->path;
4029                strip_prefix(opt->prefix_length, &name_a, &name_b);
4030                write_name_quoted(name_a, opt->file, inter_name_termination);
4031                write_name_quoted(name_b, opt->file, line_termination);
4032        } else {
4033                const char *name_a, *name_b;
4034                name_a = p->one->mode ? p->one->path : p->two->path;
4035                name_b = NULL;
4036                strip_prefix(opt->prefix_length, &name_a, &name_b);
4037                write_name_quoted(name_a, opt->file, line_termination);
4038        }
4039}
4040
4041int diff_unmodified_pair(struct diff_filepair *p)
4042{
4043        /* This function is written stricter than necessary to support
4044         * the currently implemented transformers, but the idea is to
4045         * let transformers to produce diff_filepairs any way they want,
4046         * and filter and clean them up here before producing the output.
4047         */
4048        struct diff_filespec *one = p->one, *two = p->two;
4049
4050        if (DIFF_PAIR_UNMERGED(p))
4051                return 0; /* unmerged is interesting */
4052
4053        /* deletion, addition, mode or type change
4054         * and rename are all interesting.
4055         */
4056        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4057            DIFF_PAIR_MODE_CHANGED(p) ||
4058            strcmp(one->path, two->path))
4059                return 0;
4060
4061        /* both are valid and point at the same path.  that is, we are
4062         * dealing with a change.
4063         */
4064        if (one->sha1_valid && two->sha1_valid &&
4065            !hashcmp(one->sha1, two->sha1) &&
4066            !one->dirty_submodule && !two->dirty_submodule)
4067                return 1; /* no change */
4068        if (!one->sha1_valid && !two->sha1_valid)
4069                return 1; /* both look at the same file on the filesystem. */
4070        return 0;
4071}
4072
4073static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4074{
4075        if (diff_unmodified_pair(p))
4076                return;
4077
4078        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4079            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4080                return; /* no tree diffs in patch format */
4081
4082        run_diff(p, o);
4083}
4084
4085static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4086                            struct diffstat_t *diffstat)
4087{
4088        if (diff_unmodified_pair(p))
4089                return;
4090
4091        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4092            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4093                return; /* no useful stat for tree diffs */
4094
4095        run_diffstat(p, o, diffstat);
4096}
4097
4098static void diff_flush_checkdiff(struct diff_filepair *p,
4099                struct diff_options *o)
4100{
4101        if (diff_unmodified_pair(p))
4102                return;
4103
4104        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4105            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4106                return; /* nothing to check in tree diffs */
4107
4108        run_checkdiff(p, o);
4109}
4110
4111int diff_queue_is_empty(void)
4112{
4113        struct diff_queue_struct *q = &diff_queued_diff;
4114        int i;
4115        for (i = 0; i < q->nr; i++)
4116                if (!diff_unmodified_pair(q->queue[i]))
4117                        return 0;
4118        return 1;
4119}
4120
4121#if DIFF_DEBUG
4122void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4123{
4124        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4125                x, one ? one : "",
4126                s->path,
4127                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4128                s->mode,
4129                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4130        fprintf(stderr, "queue[%d] %s size %lu\n",
4131                x, one ? one : "",
4132                s->size);
4133}
4134
4135void diff_debug_filepair(const struct diff_filepair *p, int i)
4136{
4137        diff_debug_filespec(p->one, i, "one");
4138        diff_debug_filespec(p->two, i, "two");
4139        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4140                p->score, p->status ? p->status : '?',
4141                p->one->rename_used, p->broken_pair);
4142}
4143
4144void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4145{
4146        int i;
4147        if (msg)
4148                fprintf(stderr, "%s\n", msg);
4149        fprintf(stderr, "q->nr = %d\n", q->nr);
4150        for (i = 0; i < q->nr; i++) {
4151                struct diff_filepair *p = q->queue[i];
4152                diff_debug_filepair(p, i);
4153        }
4154}
4155#endif
4156
4157static void diff_resolve_rename_copy(void)
4158{
4159        int i;
4160        struct diff_filepair *p;
4161        struct diff_queue_struct *q = &diff_queued_diff;
4162
4163        diff_debug_queue("resolve-rename-copy", q);
4164
4165        for (i = 0; i < q->nr; i++) {
4166                p = q->queue[i];
4167                p->status = 0; /* undecided */
4168                if (DIFF_PAIR_UNMERGED(p))
4169                        p->status = DIFF_STATUS_UNMERGED;
4170                else if (!DIFF_FILE_VALID(p->one))
4171                        p->status = DIFF_STATUS_ADDED;
4172                else if (!DIFF_FILE_VALID(p->two))
4173                        p->status = DIFF_STATUS_DELETED;
4174                else if (DIFF_PAIR_TYPE_CHANGED(p))
4175                        p->status = DIFF_STATUS_TYPE_CHANGED;
4176
4177                /* from this point on, we are dealing with a pair
4178                 * whose both sides are valid and of the same type, i.e.
4179                 * either in-place edit or rename/copy edit.
4180                 */
4181                else if (DIFF_PAIR_RENAME(p)) {
4182                        /*
4183                         * A rename might have re-connected a broken
4184                         * pair up, causing the pathnames to be the
4185                         * same again. If so, that's not a rename at
4186                         * all, just a modification..
4187                         *
4188                         * Otherwise, see if this source was used for
4189                         * multiple renames, in which case we decrement
4190                         * the count, and call it a copy.
4191                         */
4192                        if (!strcmp(p->one->path, p->two->path))
4193                                p->status = DIFF_STATUS_MODIFIED;
4194                        else if (--p->one->rename_used > 0)
4195                                p->status = DIFF_STATUS_COPIED;
4196                        else
4197                                p->status = DIFF_STATUS_RENAMED;
4198                }
4199                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4200                         p->one->mode != p->two->mode ||
4201                         p->one->dirty_submodule ||
4202                         p->two->dirty_submodule ||
4203                         is_null_sha1(p->one->sha1))
4204                        p->status = DIFF_STATUS_MODIFIED;
4205                else {
4206                        /* This is a "no-change" entry and should not
4207                         * happen anymore, but prepare for broken callers.
4208                         */
4209                        error("feeding unmodified %s to diffcore",
4210                              p->one->path);
4211                        p->status = DIFF_STATUS_UNKNOWN;
4212                }
4213        }
4214        diff_debug_queue("resolve-rename-copy done", q);
4215}
4216
4217static int check_pair_status(struct diff_filepair *p)
4218{
4219        switch (p->status) {
4220        case DIFF_STATUS_UNKNOWN:
4221                return 0;
4222        case 0:
4223                die("internal error in diff-resolve-rename-copy");
4224        default:
4225                return 1;
4226        }
4227}
4228
4229static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4230{
4231        int fmt = opt->output_format;
4232
4233        if (fmt & DIFF_FORMAT_CHECKDIFF)
4234                diff_flush_checkdiff(p, opt);
4235        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4236                diff_flush_raw(p, opt);
4237        else if (fmt & DIFF_FORMAT_NAME) {
4238                const char *name_a, *name_b;
4239                name_a = p->two->path;
4240                name_b = NULL;
4241                strip_prefix(opt->prefix_length, &name_a, &name_b);
4242                write_name_quoted(name_a, opt->file, opt->line_termination);
4243        }
4244}
4245
4246static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4247{
4248        if (fs->mode)
4249                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4250        else
4251                fprintf(file, " %s ", newdelete);
4252        write_name_quoted(fs->path, file, '\n');
4253}
4254
4255
4256static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4257                const char *line_prefix)
4258{
4259        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4260                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4261                        p->two->mode, show_name ? ' ' : '\n');
4262                if (show_name) {
4263                        write_name_quoted(p->two->path, file, '\n');
4264                }
4265        }
4266}
4267
4268static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4269                        const char *line_prefix)
4270{
4271        char *names = pprint_rename(p->one->path, p->two->path);
4272
4273        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4274        free(names);
4275        show_mode_change(file, p, 0, line_prefix);
4276}
4277
4278static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4279{
4280        FILE *file = opt->file;
4281        const char *line_prefix = diff_line_prefix(opt);
4282
4283        switch(p->status) {
4284        case DIFF_STATUS_DELETED:
4285                fputs(line_prefix, file);
4286                show_file_mode_name(file, "delete", p->one);
4287                break;
4288        case DIFF_STATUS_ADDED:
4289                fputs(line_prefix, file);
4290                show_file_mode_name(file, "create", p->two);
4291                break;
4292        case DIFF_STATUS_COPIED:
4293                fputs(line_prefix, file);
4294                show_rename_copy(file, "copy", p, line_prefix);
4295                break;
4296        case DIFF_STATUS_RENAMED:
4297                fputs(line_prefix, file);
4298                show_rename_copy(file, "rename", p, line_prefix);
4299                break;
4300        default:
4301                if (p->score) {
4302                        fprintf(file, "%s rewrite ", line_prefix);
4303                        write_name_quoted(p->two->path, file, ' ');
4304                        fprintf(file, "(%d%%)\n", similarity_index(p));
4305                }
4306                show_mode_change(file, p, !p->score, line_prefix);
4307                break;
4308        }
4309}
4310
4311struct patch_id_t {
4312        git_SHA_CTX *ctx;
4313        int patchlen;
4314};
4315
4316static int remove_space(char *line, int len)
4317{
4318        int i;
4319        char *dst = line;
4320        unsigned char c;
4321
4322        for (i = 0; i < len; i++)
4323                if (!isspace((c = line[i])))
4324                        *dst++ = c;
4325
4326        return dst - line;
4327}
4328
4329static void patch_id_consume(void *priv, char *line, unsigned long len)
4330{
4331        struct patch_id_t *data = priv;
4332        int new_len;
4333
4334        /* Ignore line numbers when computing the SHA1 of the patch */
4335        if (starts_with(line, "@@ -"))
4336                return;
4337
4338        new_len = remove_space(line, len);
4339
4340        git_SHA1_Update(data->ctx, line, new_len);
4341        data->patchlen += new_len;
4342}
4343
4344/* returns 0 upon success, and writes result into sha1 */
4345static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4346{
4347        struct diff_queue_struct *q = &diff_queued_diff;
4348        int i;
4349        git_SHA_CTX ctx;
4350        struct patch_id_t data;
4351        char buffer[PATH_MAX * 4 + 20];
4352
4353        git_SHA1_Init(&ctx);
4354        memset(&data, 0, sizeof(struct patch_id_t));
4355        data.ctx = &ctx;
4356
4357        for (i = 0; i < q->nr; i++) {
4358                xpparam_t xpp;
4359                xdemitconf_t xecfg;
4360                mmfile_t mf1, mf2;
4361                struct diff_filepair *p = q->queue[i];
4362                int len1, len2;
4363
4364                memset(&xpp, 0, sizeof(xpp));
4365                memset(&xecfg, 0, sizeof(xecfg));
4366                if (p->status == 0)
4367                        return error("internal diff status error");
4368                if (p->status == DIFF_STATUS_UNKNOWN)
4369                        continue;
4370                if (diff_unmodified_pair(p))
4371                        continue;
4372                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4373                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4374                        continue;
4375                if (DIFF_PAIR_UNMERGED(p))
4376                        continue;
4377
4378                diff_fill_sha1_info(p->one);
4379                diff_fill_sha1_info(p->two);
4380                if (fill_mmfile(&mf1, p->one) < 0 ||
4381                                fill_mmfile(&mf2, p->two) < 0)
4382                        return error("unable to read files to diff");
4383
4384                len1 = remove_space(p->one->path, strlen(p->one->path));
4385                len2 = remove_space(p->two->path, strlen(p->two->path));
4386                if (p->one->mode == 0)
4387                        len1 = snprintf(buffer, sizeof(buffer),
4388                                        "diff--gita/%.*sb/%.*s"
4389                                        "newfilemode%06o"
4390                                        "---/dev/null"
4391                                        "+++b/%.*s",
4392                                        len1, p->one->path,
4393                                        len2, p->two->path,
4394                                        p->two->mode,
4395                                        len2, p->two->path);
4396                else if (p->two->mode == 0)
4397                        len1 = snprintf(buffer, sizeof(buffer),
4398                                        "diff--gita/%.*sb/%.*s"
4399                                        "deletedfilemode%06o"
4400                                        "---a/%.*s"
4401                                        "+++/dev/null",
4402                                        len1, p->one->path,
4403                                        len2, p->two->path,
4404                                        p->one->mode,
4405                                        len1, p->one->path);
4406                else
4407                        len1 = snprintf(buffer, sizeof(buffer),
4408                                        "diff--gita/%.*sb/%.*s"
4409                                        "---a/%.*s"
4410                                        "+++b/%.*s",
4411                                        len1, p->one->path,
4412                                        len2, p->two->path,
4413                                        len1, p->one->path,
4414                                        len2, p->two->path);
4415                git_SHA1_Update(&ctx, buffer, len1);
4416
4417                if (diff_filespec_is_binary(p->one) ||
4418                    diff_filespec_is_binary(p->two)) {
4419                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4420                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4421                        continue;
4422                }
4423
4424                xpp.flags = 0;
4425                xecfg.ctxlen = 3;
4426                xecfg.flags = 0;
4427                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4428                              &xpp, &xecfg);
4429        }
4430
4431        git_SHA1_Final(sha1, &ctx);
4432        return 0;
4433}
4434
4435int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4436{
4437        struct diff_queue_struct *q = &diff_queued_diff;
4438        int i;
4439        int result = diff_get_patch_id(options, sha1);
4440
4441        for (i = 0; i < q->nr; i++)
4442                diff_free_filepair(q->queue[i]);
4443
4444        free(q->queue);
4445        DIFF_QUEUE_CLEAR(q);
4446
4447        return result;
4448}
4449
4450static int is_summary_empty(const struct diff_queue_struct *q)
4451{
4452        int i;
4453
4454        for (i = 0; i < q->nr; i++) {
4455                const struct diff_filepair *p = q->queue[i];
4456
4457                switch (p->status) {
4458                case DIFF_STATUS_DELETED:
4459                case DIFF_STATUS_ADDED:
4460                case DIFF_STATUS_COPIED:
4461                case DIFF_STATUS_RENAMED:
4462                        return 0;
4463                default:
4464                        if (p->score)
4465                                return 0;
4466                        if (p->one->mode && p->two->mode &&
4467                            p->one->mode != p->two->mode)
4468                                return 0;
4469                        break;
4470                }
4471        }
4472        return 1;
4473}
4474
4475static const char rename_limit_warning[] =
4476"inexact rename detection was skipped due to too many files.";
4477
4478static const char degrade_cc_to_c_warning[] =
4479"only found copies from modified paths due to too many files.";
4480
4481static const char rename_limit_advice[] =
4482"you may want to set your %s variable to at least "
4483"%d and retry the command.";
4484
4485void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4486{
4487        if (degraded_cc)
4488                warning(degrade_cc_to_c_warning);
4489        else if (needed)
4490                warning(rename_limit_warning);
4491        else
4492                return;
4493        if (0 < needed && needed < 32767)
4494                warning(rename_limit_advice, varname, needed);
4495}
4496
4497void diff_flush(struct diff_options *options)
4498{
4499        struct diff_queue_struct *q = &diff_queued_diff;
4500        int i, output_format = options->output_format;
4501        int separator = 0;
4502        int dirstat_by_line = 0;
4503
4504        /*
4505         * Order: raw, stat, summary, patch
4506         * or:    name/name-status/checkdiff (other bits clear)
4507         */
4508        if (!q->nr)
4509                goto free_queue;
4510
4511        if (output_format & (DIFF_FORMAT_RAW |
4512                             DIFF_FORMAT_NAME |
4513                             DIFF_FORMAT_NAME_STATUS |
4514                             DIFF_FORMAT_CHECKDIFF)) {
4515                for (i = 0; i < q->nr; i++) {
4516                        struct diff_filepair *p = q->queue[i];
4517                        if (check_pair_status(p))
4518                                flush_one_pair(p, options);
4519                }
4520                separator++;
4521        }
4522
4523        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4524                dirstat_by_line = 1;
4525
4526        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4527            dirstat_by_line) {
4528                struct diffstat_t diffstat;
4529
4530                memset(&diffstat, 0, sizeof(struct diffstat_t));
4531                for (i = 0; i < q->nr; i++) {
4532                        struct diff_filepair *p = q->queue[i];
4533                        if (check_pair_status(p))
4534                                diff_flush_stat(p, options, &diffstat);
4535                }
4536                if (output_format & DIFF_FORMAT_NUMSTAT)
4537                        show_numstat(&diffstat, options);
4538                if (output_format & DIFF_FORMAT_DIFFSTAT)
4539                        show_stats(&diffstat, options);
4540                if (output_format & DIFF_FORMAT_SHORTSTAT)
4541                        show_shortstats(&diffstat, options);
4542                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4543                        show_dirstat_by_line(&diffstat, options);
4544                free_diffstat_info(&diffstat);
4545                separator++;
4546        }
4547        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4548                show_dirstat(options);
4549
4550        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4551                for (i = 0; i < q->nr; i++) {
4552                        diff_summary(options, q->queue[i]);
4553                }
4554                separator++;
4555        }
4556
4557        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4558            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4559            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4560                /*
4561                 * run diff_flush_patch for the exit status. setting
4562                 * options->file to /dev/null should be safe, because we
4563                 * aren't supposed to produce any output anyway.
4564                 */
4565                if (options->close_file)
4566                        fclose(options->file);
4567                options->file = fopen("/dev/null", "w");
4568                if (!options->file)
4569                        die_errno("Could not open /dev/null");
4570                options->close_file = 1;
4571                for (i = 0; i < q->nr; i++) {
4572                        struct diff_filepair *p = q->queue[i];
4573                        if (check_pair_status(p))
4574                                diff_flush_patch(p, options);
4575                        if (options->found_changes)
4576                                break;
4577                }
4578        }
4579
4580        if (output_format & DIFF_FORMAT_PATCH) {
4581                if (separator) {
4582                        fprintf(options->file, "%s%c",
4583                                diff_line_prefix(options),
4584                                options->line_termination);
4585                        if (options->stat_sep) {
4586                                /* attach patch instead of inline */
4587                                fputs(options->stat_sep, options->file);
4588                        }
4589                }
4590
4591                for (i = 0; i < q->nr; i++) {
4592                        struct diff_filepair *p = q->queue[i];
4593                        if (check_pair_status(p))
4594                                diff_flush_patch(p, options);
4595                }
4596        }
4597
4598        if (output_format & DIFF_FORMAT_CALLBACK)
4599                options->format_callback(q, options, options->format_callback_data);
4600
4601        for (i = 0; i < q->nr; i++)
4602                diff_free_filepair(q->queue[i]);
4603free_queue:
4604        free(q->queue);
4605        DIFF_QUEUE_CLEAR(q);
4606        if (options->close_file)
4607                fclose(options->file);
4608
4609        /*
4610         * Report the content-level differences with HAS_CHANGES;
4611         * diff_addremove/diff_change does not set the bit when
4612         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4613         */
4614        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4615                if (options->found_changes)
4616                        DIFF_OPT_SET(options, HAS_CHANGES);
4617                else
4618                        DIFF_OPT_CLR(options, HAS_CHANGES);
4619        }
4620}
4621
4622static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4623{
4624        return (((p->status == DIFF_STATUS_MODIFIED) &&
4625                 ((p->score &&
4626                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4627                  (!p->score &&
4628                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4629                ((p->status != DIFF_STATUS_MODIFIED) &&
4630                 filter_bit_tst(p->status, options)));
4631}
4632
4633static void diffcore_apply_filter(struct diff_options *options)
4634{
4635        int i;
4636        struct diff_queue_struct *q = &diff_queued_diff;
4637        struct diff_queue_struct outq;
4638
4639        DIFF_QUEUE_CLEAR(&outq);
4640
4641        if (!options->filter)
4642                return;
4643
4644        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4645                int found;
4646                for (i = found = 0; !found && i < q->nr; i++) {
4647                        if (match_filter(options, q->queue[i]))
4648                                found++;
4649                }
4650                if (found)
4651                        return;
4652
4653                /* otherwise we will clear the whole queue
4654                 * by copying the empty outq at the end of this
4655                 * function, but first clear the current entries
4656                 * in the queue.
4657                 */
4658                for (i = 0; i < q->nr; i++)
4659                        diff_free_filepair(q->queue[i]);
4660        }
4661        else {
4662                /* Only the matching ones */
4663                for (i = 0; i < q->nr; i++) {
4664                        struct diff_filepair *p = q->queue[i];
4665                        if (match_filter(options, p))
4666                                diff_q(&outq, p);
4667                        else
4668                                diff_free_filepair(p);
4669                }
4670        }
4671        free(q->queue);
4672        *q = outq;
4673}
4674
4675/* Check whether two filespecs with the same mode and size are identical */
4676static int diff_filespec_is_identical(struct diff_filespec *one,
4677                                      struct diff_filespec *two)
4678{
4679        if (S_ISGITLINK(one->mode))
4680                return 0;
4681        if (diff_populate_filespec(one, 0))
4682                return 0;
4683        if (diff_populate_filespec(two, 0))
4684                return 0;
4685        return !memcmp(one->data, two->data, one->size);
4686}
4687
4688static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4689{
4690        if (p->done_skip_stat_unmatch)
4691                return p->skip_stat_unmatch_result;
4692
4693        p->done_skip_stat_unmatch = 1;
4694        p->skip_stat_unmatch_result = 0;
4695        /*
4696         * 1. Entries that come from stat info dirtiness
4697         *    always have both sides (iow, not create/delete),
4698         *    one side of the object name is unknown, with
4699         *    the same mode and size.  Keep the ones that
4700         *    do not match these criteria.  They have real
4701         *    differences.
4702         *
4703         * 2. At this point, the file is known to be modified,
4704         *    with the same mode and size, and the object
4705         *    name of one side is unknown.  Need to inspect
4706         *    the identical contents.
4707         */
4708        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4709            !DIFF_FILE_VALID(p->two) ||
4710            (p->one->sha1_valid && p->two->sha1_valid) ||
4711            (p->one->mode != p->two->mode) ||
4712            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4713            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4714            (p->one->size != p->two->size) ||
4715            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4716                p->skip_stat_unmatch_result = 1;
4717        return p->skip_stat_unmatch_result;
4718}
4719
4720static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4721{
4722        int i;
4723        struct diff_queue_struct *q = &diff_queued_diff;
4724        struct diff_queue_struct outq;
4725        DIFF_QUEUE_CLEAR(&outq);
4726
4727        for (i = 0; i < q->nr; i++) {
4728                struct diff_filepair *p = q->queue[i];
4729
4730                if (diff_filespec_check_stat_unmatch(p))
4731                        diff_q(&outq, p);
4732                else {
4733                        /*
4734                         * The caller can subtract 1 from skip_stat_unmatch
4735                         * to determine how many paths were dirty only
4736                         * due to stat info mismatch.
4737                         */
4738                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4739                                diffopt->skip_stat_unmatch++;
4740                        diff_free_filepair(p);
4741                }
4742        }
4743        free(q->queue);
4744        *q = outq;
4745}
4746
4747static int diffnamecmp(const void *a_, const void *b_)
4748{
4749        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4750        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4751        const char *name_a, *name_b;
4752
4753        name_a = a->one ? a->one->path : a->two->path;
4754        name_b = b->one ? b->one->path : b->two->path;
4755        return strcmp(name_a, name_b);
4756}
4757
4758void diffcore_fix_diff_index(struct diff_options *options)
4759{
4760        struct diff_queue_struct *q = &diff_queued_diff;
4761        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4762}
4763
4764void diffcore_std(struct diff_options *options)
4765{
4766        /* NOTE please keep the following in sync with diff_tree_combined() */
4767        if (options->skip_stat_unmatch)
4768                diffcore_skip_stat_unmatch(options);
4769        if (!options->found_follow) {
4770                /* See try_to_follow_renames() in tree-diff.c */
4771                if (options->break_opt != -1)
4772                        diffcore_break(options->break_opt);
4773                if (options->detect_rename)
4774                        diffcore_rename(options);
4775                if (options->break_opt != -1)
4776                        diffcore_merge_broken();
4777        }
4778        if (options->pickaxe)
4779                diffcore_pickaxe(options);
4780        if (options->orderfile)
4781                diffcore_order(options->orderfile);
4782        if (!options->found_follow)
4783                /* See try_to_follow_renames() in tree-diff.c */
4784                diff_resolve_rename_copy();
4785        diffcore_apply_filter(options);
4786
4787        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4788                DIFF_OPT_SET(options, HAS_CHANGES);
4789        else
4790                DIFF_OPT_CLR(options, HAS_CHANGES);
4791
4792        options->found_follow = 0;
4793}
4794
4795int diff_result_code(struct diff_options *opt, int status)
4796{
4797        int result = 0;
4798
4799        diff_warn_rename_limit("diff.renameLimit",
4800                               opt->needed_rename_limit,
4801                               opt->degraded_cc_to_c);
4802        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4803            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4804                return status;
4805        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4806            DIFF_OPT_TST(opt, HAS_CHANGES))
4807                result |= 01;
4808        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4809            DIFF_OPT_TST(opt, CHECK_FAILED))
4810                result |= 02;
4811        return result;
4812}
4813
4814int diff_can_quit_early(struct diff_options *opt)
4815{
4816        return (DIFF_OPT_TST(opt, QUICK) &&
4817                !opt->filter &&
4818                DIFF_OPT_TST(opt, HAS_CHANGES));
4819}
4820
4821/*
4822 * Shall changes to this submodule be ignored?
4823 *
4824 * Submodule changes can be configured to be ignored separately for each path,
4825 * but that configuration can be overridden from the command line.
4826 */
4827static int is_submodule_ignored(const char *path, struct diff_options *options)
4828{
4829        int ignored = 0;
4830        unsigned orig_flags = options->flags;
4831        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4832                set_diffopt_flags_from_submodule_config(options, path);
4833        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4834                ignored = 1;
4835        options->flags = orig_flags;
4836        return ignored;
4837}
4838
4839void diff_addremove(struct diff_options *options,
4840                    int addremove, unsigned mode,
4841                    const unsigned char *sha1,
4842                    int sha1_valid,
4843                    const char *concatpath, unsigned dirty_submodule)
4844{
4845        struct diff_filespec *one, *two;
4846
4847        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4848                return;
4849
4850        /* This may look odd, but it is a preparation for
4851         * feeding "there are unchanged files which should
4852         * not produce diffs, but when you are doing copy
4853         * detection you would need them, so here they are"
4854         * entries to the diff-core.  They will be prefixed
4855         * with something like '=' or '*' (I haven't decided
4856         * which but should not make any difference).
4857         * Feeding the same new and old to diff_change()
4858         * also has the same effect.
4859         * Before the final output happens, they are pruned after
4860         * merged into rename/copy pairs as appropriate.
4861         */
4862        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4863                addremove = (addremove == '+' ? '-' :
4864                             addremove == '-' ? '+' : addremove);
4865
4866        if (options->prefix &&
4867            strncmp(concatpath, options->prefix, options->prefix_length))
4868                return;
4869
4870        one = alloc_filespec(concatpath);
4871        two = alloc_filespec(concatpath);
4872
4873        if (addremove != '+')
4874                fill_filespec(one, sha1, sha1_valid, mode);
4875        if (addremove != '-') {
4876                fill_filespec(two, sha1, sha1_valid, mode);
4877                two->dirty_submodule = dirty_submodule;
4878        }
4879
4880        diff_queue(&diff_queued_diff, one, two);
4881        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4882                DIFF_OPT_SET(options, HAS_CHANGES);
4883}
4884
4885void diff_change(struct diff_options *options,
4886                 unsigned old_mode, unsigned new_mode,
4887                 const unsigned char *old_sha1,
4888                 const unsigned char *new_sha1,
4889                 int old_sha1_valid, int new_sha1_valid,
4890                 const char *concatpath,
4891                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4892{
4893        struct diff_filespec *one, *two;
4894        struct diff_filepair *p;
4895
4896        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4897            is_submodule_ignored(concatpath, options))
4898                return;
4899
4900        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4901                unsigned tmp;
4902                const unsigned char *tmp_c;
4903                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4904                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4905                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4906                        new_sha1_valid = tmp;
4907                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4908                        new_dirty_submodule = tmp;
4909        }
4910
4911        if (options->prefix &&
4912            strncmp(concatpath, options->prefix, options->prefix_length))
4913                return;
4914
4915        one = alloc_filespec(concatpath);
4916        two = alloc_filespec(concatpath);
4917        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4918        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4919        one->dirty_submodule = old_dirty_submodule;
4920        two->dirty_submodule = new_dirty_submodule;
4921        p = diff_queue(&diff_queued_diff, one, two);
4922
4923        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4924                return;
4925
4926        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
4927            !diff_filespec_check_stat_unmatch(p))
4928                return;
4929
4930        DIFF_OPT_SET(options, HAS_CHANGES);
4931}
4932
4933struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4934{
4935        struct diff_filepair *pair;
4936        struct diff_filespec *one, *two;
4937
4938        if (options->prefix &&
4939            strncmp(path, options->prefix, options->prefix_length))
4940                return NULL;
4941
4942        one = alloc_filespec(path);
4943        two = alloc_filespec(path);
4944        pair = diff_queue(&diff_queued_diff, one, two);
4945        pair->is_unmerged = 1;
4946        return pair;
4947}
4948
4949static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4950                size_t *outsize)
4951{
4952        struct diff_tempfile *temp;
4953        const char *argv[3];
4954        const char **arg = argv;
4955        struct child_process child = CHILD_PROCESS_INIT;
4956        struct strbuf buf = STRBUF_INIT;
4957        int err = 0;
4958
4959        temp = prepare_temp_file(spec->path, spec);
4960        *arg++ = pgm;
4961        *arg++ = temp->name;
4962        *arg = NULL;
4963
4964        child.use_shell = 1;
4965        child.argv = argv;
4966        child.out = -1;
4967        if (start_command(&child)) {
4968                remove_tempfile();
4969                return NULL;
4970        }
4971
4972        if (strbuf_read(&buf, child.out, 0) < 0)
4973                err = error("error reading from textconv command '%s'", pgm);
4974        close(child.out);
4975
4976        if (finish_command(&child) || err) {
4977                strbuf_release(&buf);
4978                remove_tempfile();
4979                return NULL;
4980        }
4981        remove_tempfile();
4982
4983        return strbuf_detach(&buf, outsize);
4984}
4985
4986size_t fill_textconv(struct userdiff_driver *driver,
4987                     struct diff_filespec *df,
4988                     char **outbuf)
4989{
4990        size_t size;
4991
4992        if (!driver || !driver->textconv) {
4993                if (!DIFF_FILE_VALID(df)) {
4994                        *outbuf = "";
4995                        return 0;
4996                }
4997                if (diff_populate_filespec(df, 0))
4998                        die("unable to read files to diff");
4999                *outbuf = df->data;
5000                return df->size;
5001        }
5002
5003        if (driver->textconv_cache && df->sha1_valid) {
5004                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5005                                          &size);
5006                if (*outbuf)
5007                        return size;
5008        }
5009
5010        *outbuf = run_textconv(driver->textconv, df, &size);
5011        if (!*outbuf)
5012                die("unable to read files to diff");
5013
5014        if (driver->textconv_cache && df->sha1_valid) {
5015                /* ignore errors, as we might be in a readonly repository */
5016                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5017                                size);
5018                /*
5019                 * we could save up changes and flush them all at the end,
5020                 * but we would need an extra call after all diffing is done.
5021                 * Since generating a cache entry is the slow path anyway,
5022                 * this extra overhead probably isn't a big deal.
5023                 */
5024                notes_cache_write(driver->textconv_cache);
5025        }
5026
5027        return size;
5028}
5029
5030void setup_diff_pager(struct diff_options *opt)
5031{
5032        /*
5033         * If the user asked for our exit code, then either they want --quiet
5034         * or --exit-code. We should definitely not bother with a pager in the
5035         * former case, as we will generate no output. Since we still properly
5036         * report our exit code even when a pager is run, we _could_ run a
5037         * pager with --exit-code. But since we have not done so historically,
5038         * and because it is easy to find people oneline advising "git diff
5039         * --exit-code" in hooks and other scripts, we do not do so.
5040         */
5041        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5042            check_pager_config("diff") != 0)
5043                setup_pager();
5044}