diff.con commit Merge branch 'jk/die-on-bogus-worktree-late' into maint (f2bd231)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18#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,       /* CONTEXT */
  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, "context") || !strcasecmp(var, "plain"))
  58                return DIFF_CONTEXT;
  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
 311static struct diff_tempfile {
 312        const char *name; /* filename external diff should read from */
 313        char hex[41];
 314        char mode[10];
 315        char tmp_path[PATH_MAX];
 316} diff_temp[2];
 317
 318typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 319
 320struct emit_callback {
 321        int color_diff;
 322        unsigned ws_rule;
 323        int blank_at_eof_in_preimage;
 324        int blank_at_eof_in_postimage;
 325        int lno_in_preimage;
 326        int lno_in_postimage;
 327        sane_truncate_fn truncate;
 328        const char **label_path;
 329        struct diff_words_data *diff_words;
 330        struct diff_options *opt;
 331        int *found_changesp;
 332        struct strbuf *header;
 333};
 334
 335static int count_lines(const char *data, int size)
 336{
 337        int count, ch, completely_empty = 1, nl_just_seen = 0;
 338        count = 0;
 339        while (0 < size--) {
 340                ch = *data++;
 341                if (ch == '\n') {
 342                        count++;
 343                        nl_just_seen = 1;
 344                        completely_empty = 0;
 345                }
 346                else {
 347                        nl_just_seen = 0;
 348                        completely_empty = 0;
 349                }
 350        }
 351        if (completely_empty)
 352                return 0;
 353        if (!nl_just_seen)
 354                count++; /* no trailing newline */
 355        return count;
 356}
 357
 358static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 359{
 360        if (!DIFF_FILE_VALID(one)) {
 361                mf->ptr = (char *)""; /* does not matter */
 362                mf->size = 0;
 363                return 0;
 364        }
 365        else if (diff_populate_filespec(one, 0))
 366                return -1;
 367
 368        mf->ptr = one->data;
 369        mf->size = one->size;
 370        return 0;
 371}
 372
 373/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 374static unsigned long diff_filespec_size(struct diff_filespec *one)
 375{
 376        if (!DIFF_FILE_VALID(one))
 377                return 0;
 378        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 379        return one->size;
 380}
 381
 382static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 383{
 384        char *ptr = mf->ptr;
 385        long size = mf->size;
 386        int cnt = 0;
 387
 388        if (!size)
 389                return cnt;
 390        ptr += size - 1; /* pointing at the very end */
 391        if (*ptr != '\n')
 392                ; /* incomplete line */
 393        else
 394                ptr--; /* skip the last LF */
 395        while (mf->ptr < ptr) {
 396                char *prev_eol;
 397                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 398                        if (*prev_eol == '\n')
 399                                break;
 400                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 401                        break;
 402                cnt++;
 403                ptr = prev_eol - 1;
 404        }
 405        return cnt;
 406}
 407
 408static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 409                               struct emit_callback *ecbdata)
 410{
 411        int l1, l2, at;
 412        unsigned ws_rule = ecbdata->ws_rule;
 413        l1 = count_trailing_blank(mf1, ws_rule);
 414        l2 = count_trailing_blank(mf2, ws_rule);
 415        if (l2 <= l1) {
 416                ecbdata->blank_at_eof_in_preimage = 0;
 417                ecbdata->blank_at_eof_in_postimage = 0;
 418                return;
 419        }
 420        at = count_lines(mf1->ptr, mf1->size);
 421        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 422
 423        at = count_lines(mf2->ptr, mf2->size);
 424        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 425}
 426
 427static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 428                        int first, const char *line, int len)
 429{
 430        int has_trailing_newline, has_trailing_carriage_return;
 431        int nofirst;
 432        FILE *file = o->file;
 433
 434        fputs(diff_line_prefix(o), file);
 435
 436        if (len == 0) {
 437                has_trailing_newline = (first == '\n');
 438                has_trailing_carriage_return = (!has_trailing_newline &&
 439                                                (first == '\r'));
 440                nofirst = has_trailing_newline || has_trailing_carriage_return;
 441        } else {
 442                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 443                if (has_trailing_newline)
 444                        len--;
 445                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 446                if (has_trailing_carriage_return)
 447                        len--;
 448                nofirst = 0;
 449        }
 450
 451        if (len || !nofirst) {
 452                fputs(set, file);
 453                if (!nofirst)
 454                        fputc(first, file);
 455                fwrite(line, len, 1, file);
 456                fputs(reset, file);
 457        }
 458        if (has_trailing_carriage_return)
 459                fputc('\r', file);
 460        if (has_trailing_newline)
 461                fputc('\n', file);
 462}
 463
 464static void emit_line(struct diff_options *o, const char *set, const char *reset,
 465                      const char *line, int len)
 466{
 467        emit_line_0(o, set, reset, line[0], line+1, len-1);
 468}
 469
 470static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 471{
 472        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 473              ecbdata->blank_at_eof_in_preimage &&
 474              ecbdata->blank_at_eof_in_postimage &&
 475              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 476              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 477                return 0;
 478        return ws_blank_line(line, len, ecbdata->ws_rule);
 479}
 480
 481static void emit_add_line(const char *reset,
 482                          struct emit_callback *ecbdata,
 483                          const char *line, int len)
 484{
 485        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 486        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 487
 488        if (!*ws)
 489                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 490        else if (new_blank_line_at_eof(ecbdata, line, len))
 491                /* Blank line at EOF - paint '+' as well */
 492                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 493        else {
 494                /* Emit just the prefix, then the rest. */
 495                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 496                ws_check_emit(line, len, ecbdata->ws_rule,
 497                              ecbdata->opt->file, set, reset, ws);
 498        }
 499}
 500
 501static void emit_hunk_header(struct emit_callback *ecbdata,
 502                             const char *line, int len)
 503{
 504        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 505        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 506        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 507        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 508        static const char atat[2] = { '@', '@' };
 509        const char *cp, *ep;
 510        struct strbuf msgbuf = STRBUF_INIT;
 511        int org_len = len;
 512        int i = 1;
 513
 514        /*
 515         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 516         * it always is at least 10 bytes long.
 517         */
 518        if (len < 10 ||
 519            memcmp(line, atat, 2) ||
 520            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 521                emit_line(ecbdata->opt, context, reset, line, len);
 522                return;
 523        }
 524        ep += 2; /* skip over @@ */
 525
 526        /* The hunk header in fraginfo color */
 527        strbuf_addstr(&msgbuf, frag);
 528        strbuf_add(&msgbuf, line, ep - line);
 529        strbuf_addstr(&msgbuf, reset);
 530
 531        /*
 532         * trailing "\r\n"
 533         */
 534        for ( ; i < 3; i++)
 535                if (line[len - i] == '\r' || line[len - i] == '\n')
 536                        len--;
 537
 538        /* blank before the func header */
 539        for (cp = ep; ep - line < len; ep++)
 540                if (*ep != ' ' && *ep != '\t')
 541                        break;
 542        if (ep != cp) {
 543                strbuf_addstr(&msgbuf, context);
 544                strbuf_add(&msgbuf, cp, ep - cp);
 545                strbuf_addstr(&msgbuf, reset);
 546        }
 547
 548        if (ep < line + len) {
 549                strbuf_addstr(&msgbuf, func);
 550                strbuf_add(&msgbuf, ep, line + len - ep);
 551                strbuf_addstr(&msgbuf, reset);
 552        }
 553
 554        strbuf_add(&msgbuf, line + len, org_len - len);
 555        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 556        strbuf_release(&msgbuf);
 557}
 558
 559static struct diff_tempfile *claim_diff_tempfile(void) {
 560        int i;
 561        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 562                if (!diff_temp[i].name)
 563                        return diff_temp + i;
 564        die("BUG: diff is failing to clean up its tempfiles");
 565}
 566
 567static int remove_tempfile_installed;
 568
 569static void remove_tempfile(void)
 570{
 571        int i;
 572        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 573                if (diff_temp[i].name == diff_temp[i].tmp_path)
 574                        unlink_or_warn(diff_temp[i].name);
 575                diff_temp[i].name = NULL;
 576        }
 577}
 578
 579static void remove_tempfile_on_signal(int signo)
 580{
 581        remove_tempfile();
 582        sigchain_pop(signo);
 583        raise(signo);
 584}
 585
 586static void print_line_count(FILE *file, int count)
 587{
 588        switch (count) {
 589        case 0:
 590                fprintf(file, "0,0");
 591                break;
 592        case 1:
 593                fprintf(file, "1");
 594                break;
 595        default:
 596                fprintf(file, "1,%d", count);
 597                break;
 598        }
 599}
 600
 601static void emit_rewrite_lines(struct emit_callback *ecb,
 602                               int prefix, const char *data, int size)
 603{
 604        const char *endp = NULL;
 605        static const char *nneof = " No newline at end of file\n";
 606        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 607        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 608
 609        while (0 < size) {
 610                int len;
 611
 612                endp = memchr(data, '\n', size);
 613                len = endp ? (endp - data + 1) : size;
 614                if (prefix != '+') {
 615                        ecb->lno_in_preimage++;
 616                        emit_line_0(ecb->opt, old, reset, '-',
 617                                    data, len);
 618                } else {
 619                        ecb->lno_in_postimage++;
 620                        emit_add_line(reset, ecb, data, len);
 621                }
 622                size -= len;
 623                data += len;
 624        }
 625        if (!endp) {
 626                const char *context = diff_get_color(ecb->color_diff,
 627                                                     DIFF_CONTEXT);
 628                putc('\n', ecb->opt->file);
 629                emit_line_0(ecb->opt, context, reset, '\\',
 630                            nneof, strlen(nneof));
 631        }
 632}
 633
 634static void emit_rewrite_diff(const char *name_a,
 635                              const char *name_b,
 636                              struct diff_filespec *one,
 637                              struct diff_filespec *two,
 638                              struct userdiff_driver *textconv_one,
 639                              struct userdiff_driver *textconv_two,
 640                              struct diff_options *o)
 641{
 642        int lc_a, lc_b;
 643        const char *name_a_tab, *name_b_tab;
 644        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 645        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 646        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 647        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 648        const char *a_prefix, *b_prefix;
 649        char *data_one, *data_two;
 650        size_t size_one, size_two;
 651        struct emit_callback ecbdata;
 652        const char *line_prefix = diff_line_prefix(o);
 653
 654        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 655                a_prefix = o->b_prefix;
 656                b_prefix = o->a_prefix;
 657        } else {
 658                a_prefix = o->a_prefix;
 659                b_prefix = o->b_prefix;
 660        }
 661
 662        name_a += (*name_a == '/');
 663        name_b += (*name_b == '/');
 664        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 665        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 666
 667        strbuf_reset(&a_name);
 668        strbuf_reset(&b_name);
 669        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 670        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 671
 672        size_one = fill_textconv(textconv_one, one, &data_one);
 673        size_two = fill_textconv(textconv_two, two, &data_two);
 674
 675        memset(&ecbdata, 0, sizeof(ecbdata));
 676        ecbdata.color_diff = want_color(o->use_color);
 677        ecbdata.found_changesp = &o->found_changes;
 678        ecbdata.ws_rule = whitespace_rule(name_b);
 679        ecbdata.opt = o;
 680        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 681                mmfile_t mf1, mf2;
 682                mf1.ptr = (char *)data_one;
 683                mf2.ptr = (char *)data_two;
 684                mf1.size = size_one;
 685                mf2.size = size_two;
 686                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 687        }
 688        ecbdata.lno_in_preimage = 1;
 689        ecbdata.lno_in_postimage = 1;
 690
 691        lc_a = count_lines(data_one, size_one);
 692        lc_b = count_lines(data_two, size_two);
 693        fprintf(o->file,
 694                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 695                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 696                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 697                line_prefix, fraginfo);
 698        if (!o->irreversible_delete)
 699                print_line_count(o->file, lc_a);
 700        else
 701                fprintf(o->file, "?,?");
 702        fprintf(o->file, " +");
 703        print_line_count(o->file, lc_b);
 704        fprintf(o->file, " @@%s\n", reset);
 705        if (lc_a && !o->irreversible_delete)
 706                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 707        if (lc_b)
 708                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 709        if (textconv_one)
 710                free((char *)data_one);
 711        if (textconv_two)
 712                free((char *)data_two);
 713}
 714
 715struct diff_words_buffer {
 716        mmfile_t text;
 717        long alloc;
 718        struct diff_words_orig {
 719                const char *begin, *end;
 720        } *orig;
 721        int orig_nr, orig_alloc;
 722};
 723
 724static void diff_words_append(char *line, unsigned long len,
 725                struct diff_words_buffer *buffer)
 726{
 727        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 728        line++;
 729        len--;
 730        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 731        buffer->text.size += len;
 732        buffer->text.ptr[buffer->text.size] = '\0';
 733}
 734
 735struct diff_words_style_elem {
 736        const char *prefix;
 737        const char *suffix;
 738        const char *color; /* NULL; filled in by the setup code if
 739                            * color is enabled */
 740};
 741
 742struct diff_words_style {
 743        enum diff_words_type type;
 744        struct diff_words_style_elem new, old, ctx;
 745        const char *newline;
 746};
 747
 748static struct diff_words_style diff_words_styles[] = {
 749        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 750        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 751        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 752};
 753
 754struct diff_words_data {
 755        struct diff_words_buffer minus, plus;
 756        const char *current_plus;
 757        int last_minus;
 758        struct diff_options *opt;
 759        regex_t *word_regex;
 760        enum diff_words_type type;
 761        struct diff_words_style *style;
 762};
 763
 764static int fn_out_diff_words_write_helper(FILE *fp,
 765                                          struct diff_words_style_elem *st_el,
 766                                          const char *newline,
 767                                          size_t count, const char *buf,
 768                                          const char *line_prefix)
 769{
 770        int print = 0;
 771
 772        while (count) {
 773                char *p = memchr(buf, '\n', count);
 774                if (print)
 775                        fputs(line_prefix, fp);
 776                if (p != buf) {
 777                        if (st_el->color && fputs(st_el->color, fp) < 0)
 778                                return -1;
 779                        if (fputs(st_el->prefix, fp) < 0 ||
 780                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 781                            fputs(st_el->suffix, fp) < 0)
 782                                return -1;
 783                        if (st_el->color && *st_el->color
 784                            && fputs(GIT_COLOR_RESET, fp) < 0)
 785                                return -1;
 786                }
 787                if (!p)
 788                        return 0;
 789                if (fputs(newline, fp) < 0)
 790                        return -1;
 791                count -= p + 1 - buf;
 792                buf = p + 1;
 793                print = 1;
 794        }
 795        return 0;
 796}
 797
 798/*
 799 * '--color-words' algorithm can be described as:
 800 *
 801 *   1. collect a the minus/plus lines of a diff hunk, divided into
 802 *      minus-lines and plus-lines;
 803 *
 804 *   2. break both minus-lines and plus-lines into words and
 805 *      place them into two mmfile_t with one word for each line;
 806 *
 807 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 808 *
 809 * And for the common parts of the both file, we output the plus side text.
 810 * diff_words->current_plus is used to trace the current position of the plus file
 811 * which printed. diff_words->last_minus is used to trace the last minus word
 812 * printed.
 813 *
 814 * For '--graph' to work with '--color-words', we need to output the graph prefix
 815 * on each line of color words output. Generally, there are two conditions on
 816 * which we should output the prefix.
 817 *
 818 *   1. diff_words->last_minus == 0 &&
 819 *      diff_words->current_plus == diff_words->plus.text.ptr
 820 *
 821 *      that is: the plus text must start as a new line, and if there is no minus
 822 *      word printed, a graph prefix must be printed.
 823 *
 824 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 825 *      *(diff_words->current_plus - 1) == '\n'
 826 *
 827 *      that is: a graph prefix must be printed following a '\n'
 828 */
 829static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 830{
 831        if ((diff_words->last_minus == 0 &&
 832                diff_words->current_plus == diff_words->plus.text.ptr) ||
 833                (diff_words->current_plus > diff_words->plus.text.ptr &&
 834                *(diff_words->current_plus - 1) == '\n')) {
 835                return 1;
 836        } else {
 837                return 0;
 838        }
 839}
 840
 841static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 842{
 843        struct diff_words_data *diff_words = priv;
 844        struct diff_words_style *style = diff_words->style;
 845        int minus_first, minus_len, plus_first, plus_len;
 846        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 847        struct diff_options *opt = diff_words->opt;
 848        const char *line_prefix;
 849
 850        if (line[0] != '@' || parse_hunk_header(line, len,
 851                        &minus_first, &minus_len, &plus_first, &plus_len))
 852                return;
 853
 854        assert(opt);
 855        line_prefix = diff_line_prefix(opt);
 856
 857        /* POSIX requires that first be decremented by one if len == 0... */
 858        if (minus_len) {
 859                minus_begin = diff_words->minus.orig[minus_first].begin;
 860                minus_end =
 861                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 862        } else
 863                minus_begin = minus_end =
 864                        diff_words->minus.orig[minus_first].end;
 865
 866        if (plus_len) {
 867                plus_begin = diff_words->plus.orig[plus_first].begin;
 868                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 869        } else
 870                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 871
 872        if (color_words_output_graph_prefix(diff_words)) {
 873                fputs(line_prefix, diff_words->opt->file);
 874        }
 875        if (diff_words->current_plus != plus_begin) {
 876                fn_out_diff_words_write_helper(diff_words->opt->file,
 877                                &style->ctx, style->newline,
 878                                plus_begin - diff_words->current_plus,
 879                                diff_words->current_plus, line_prefix);
 880                if (*(plus_begin - 1) == '\n')
 881                        fputs(line_prefix, diff_words->opt->file);
 882        }
 883        if (minus_begin != minus_end) {
 884                fn_out_diff_words_write_helper(diff_words->opt->file,
 885                                &style->old, style->newline,
 886                                minus_end - minus_begin, minus_begin,
 887                                line_prefix);
 888        }
 889        if (plus_begin != plus_end) {
 890                fn_out_diff_words_write_helper(diff_words->opt->file,
 891                                &style->new, style->newline,
 892                                plus_end - plus_begin, plus_begin,
 893                                line_prefix);
 894        }
 895
 896        diff_words->current_plus = plus_end;
 897        diff_words->last_minus = minus_first;
 898}
 899
 900/* This function starts looking at *begin, and returns 0 iff a word was found. */
 901static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 902                int *begin, int *end)
 903{
 904        if (word_regex && *begin < buffer->size) {
 905                regmatch_t match[1];
 906                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 907                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 908                                        '\n', match[0].rm_eo - match[0].rm_so);
 909                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 910                        *begin += match[0].rm_so;
 911                        return *begin >= *end;
 912                }
 913                return -1;
 914        }
 915
 916        /* find the next word */
 917        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 918                (*begin)++;
 919        if (*begin >= buffer->size)
 920                return -1;
 921
 922        /* find the end of the word */
 923        *end = *begin + 1;
 924        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 925                (*end)++;
 926
 927        return 0;
 928}
 929
 930/*
 931 * This function splits the words in buffer->text, stores the list with
 932 * newline separator into out, and saves the offsets of the original words
 933 * in buffer->orig.
 934 */
 935static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 936                regex_t *word_regex)
 937{
 938        int i, j;
 939        long alloc = 0;
 940
 941        out->size = 0;
 942        out->ptr = NULL;
 943
 944        /* fake an empty "0th" word */
 945        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 946        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 947        buffer->orig_nr = 1;
 948
 949        for (i = 0; i < buffer->text.size; i++) {
 950                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 951                        return;
 952
 953                /* store original boundaries */
 954                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 955                                buffer->orig_alloc);
 956                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 957                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 958                buffer->orig_nr++;
 959
 960                /* store one word */
 961                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 962                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 963                out->ptr[out->size + j - i] = '\n';
 964                out->size += j - i + 1;
 965
 966                i = j - 1;
 967        }
 968}
 969
 970/* this executes the word diff on the accumulated buffers */
 971static void diff_words_show(struct diff_words_data *diff_words)
 972{
 973        xpparam_t xpp;
 974        xdemitconf_t xecfg;
 975        mmfile_t minus, plus;
 976        struct diff_words_style *style = diff_words->style;
 977
 978        struct diff_options *opt = diff_words->opt;
 979        const char *line_prefix;
 980
 981        assert(opt);
 982        line_prefix = diff_line_prefix(opt);
 983
 984        /* special case: only removal */
 985        if (!diff_words->plus.text.size) {
 986                fputs(line_prefix, diff_words->opt->file);
 987                fn_out_diff_words_write_helper(diff_words->opt->file,
 988                        &style->old, style->newline,
 989                        diff_words->minus.text.size,
 990                        diff_words->minus.text.ptr, line_prefix);
 991                diff_words->minus.text.size = 0;
 992                return;
 993        }
 994
 995        diff_words->current_plus = diff_words->plus.text.ptr;
 996        diff_words->last_minus = 0;
 997
 998        memset(&xpp, 0, sizeof(xpp));
 999        memset(&xecfg, 0, sizeof(xecfg));
1000        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1001        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1002        xpp.flags = 0;
1003        /* as only the hunk header will be parsed, we need a 0-context */
1004        xecfg.ctxlen = 0;
1005        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1006                      &xpp, &xecfg);
1007        free(minus.ptr);
1008        free(plus.ptr);
1009        if (diff_words->current_plus != diff_words->plus.text.ptr +
1010                        diff_words->plus.text.size) {
1011                if (color_words_output_graph_prefix(diff_words))
1012                        fputs(line_prefix, diff_words->opt->file);
1013                fn_out_diff_words_write_helper(diff_words->opt->file,
1014                        &style->ctx, style->newline,
1015                        diff_words->plus.text.ptr + diff_words->plus.text.size
1016                        - diff_words->current_plus, diff_words->current_plus,
1017                        line_prefix);
1018        }
1019        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1020}
1021
1022/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1023static void diff_words_flush(struct emit_callback *ecbdata)
1024{
1025        if (ecbdata->diff_words->minus.text.size ||
1026            ecbdata->diff_words->plus.text.size)
1027                diff_words_show(ecbdata->diff_words);
1028}
1029
1030static void diff_filespec_load_driver(struct diff_filespec *one)
1031{
1032        /* Use already-loaded driver */
1033        if (one->driver)
1034                return;
1035
1036        if (S_ISREG(one->mode))
1037                one->driver = userdiff_find_by_path(one->path);
1038
1039        /* Fallback to default settings */
1040        if (!one->driver)
1041                one->driver = userdiff_find_by_name("default");
1042}
1043
1044static const char *userdiff_word_regex(struct diff_filespec *one)
1045{
1046        diff_filespec_load_driver(one);
1047        return one->driver->word_regex;
1048}
1049
1050static void init_diff_words_data(struct emit_callback *ecbdata,
1051                                 struct diff_options *orig_opts,
1052                                 struct diff_filespec *one,
1053                                 struct diff_filespec *two)
1054{
1055        int i;
1056        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1057        memcpy(o, orig_opts, sizeof(struct diff_options));
1058
1059        ecbdata->diff_words =
1060                xcalloc(1, sizeof(struct diff_words_data));
1061        ecbdata->diff_words->type = o->word_diff;
1062        ecbdata->diff_words->opt = o;
1063        if (!o->word_regex)
1064                o->word_regex = userdiff_word_regex(one);
1065        if (!o->word_regex)
1066                o->word_regex = userdiff_word_regex(two);
1067        if (!o->word_regex)
1068                o->word_regex = diff_word_regex_cfg;
1069        if (o->word_regex) {
1070                ecbdata->diff_words->word_regex = (regex_t *)
1071                        xmalloc(sizeof(regex_t));
1072                if (regcomp(ecbdata->diff_words->word_regex,
1073                            o->word_regex,
1074                            REG_EXTENDED | REG_NEWLINE))
1075                        die ("Invalid regular expression: %s",
1076                             o->word_regex);
1077        }
1078        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1079                if (o->word_diff == diff_words_styles[i].type) {
1080                        ecbdata->diff_words->style =
1081                                &diff_words_styles[i];
1082                        break;
1083                }
1084        }
1085        if (want_color(o->use_color)) {
1086                struct diff_words_style *st = ecbdata->diff_words->style;
1087                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1088                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1089                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1090        }
1091}
1092
1093static void free_diff_words_data(struct emit_callback *ecbdata)
1094{
1095        if (ecbdata->diff_words) {
1096                diff_words_flush(ecbdata);
1097                free (ecbdata->diff_words->opt);
1098                free (ecbdata->diff_words->minus.text.ptr);
1099                free (ecbdata->diff_words->minus.orig);
1100                free (ecbdata->diff_words->plus.text.ptr);
1101                free (ecbdata->diff_words->plus.orig);
1102                if (ecbdata->diff_words->word_regex) {
1103                        regfree(ecbdata->diff_words->word_regex);
1104                        free(ecbdata->diff_words->word_regex);
1105                }
1106                free(ecbdata->diff_words);
1107                ecbdata->diff_words = NULL;
1108        }
1109}
1110
1111const char *diff_get_color(int diff_use_color, enum color_diff ix)
1112{
1113        if (want_color(diff_use_color))
1114                return diff_colors[ix];
1115        return "";
1116}
1117
1118const char *diff_line_prefix(struct diff_options *opt)
1119{
1120        struct strbuf *msgbuf;
1121        if (!opt->output_prefix)
1122                return "";
1123
1124        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1125        return msgbuf->buf;
1126}
1127
1128static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1129{
1130        const char *cp;
1131        unsigned long allot;
1132        size_t l = len;
1133
1134        if (ecb->truncate)
1135                return ecb->truncate(line, len);
1136        cp = line;
1137        allot = l;
1138        while (0 < l) {
1139                (void) utf8_width(&cp, &l);
1140                if (!cp)
1141                        break; /* truncated in the middle? */
1142        }
1143        return allot - l;
1144}
1145
1146static void find_lno(const char *line, struct emit_callback *ecbdata)
1147{
1148        const char *p;
1149        ecbdata->lno_in_preimage = 0;
1150        ecbdata->lno_in_postimage = 0;
1151        p = strchr(line, '-');
1152        if (!p)
1153                return; /* cannot happen */
1154        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1155        p = strchr(p, '+');
1156        if (!p)
1157                return; /* cannot happen */
1158        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1159}
1160
1161static void fn_out_consume(void *priv, char *line, unsigned long len)
1162{
1163        struct emit_callback *ecbdata = priv;
1164        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1165        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1166        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1167        struct diff_options *o = ecbdata->opt;
1168        const char *line_prefix = diff_line_prefix(o);
1169
1170        if (ecbdata->header) {
1171                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1172                strbuf_reset(ecbdata->header);
1173                ecbdata->header = NULL;
1174        }
1175        *(ecbdata->found_changesp) = 1;
1176
1177        if (ecbdata->label_path[0]) {
1178                const char *name_a_tab, *name_b_tab;
1179
1180                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1181                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1182
1183                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1184                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1185                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1186                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1187                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1188        }
1189
1190        if (diff_suppress_blank_empty
1191            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1192                line[0] = '\n';
1193                len = 1;
1194        }
1195
1196        if (line[0] == '@') {
1197                if (ecbdata->diff_words)
1198                        diff_words_flush(ecbdata);
1199                len = sane_truncate_line(ecbdata, line, len);
1200                find_lno(line, ecbdata);
1201                emit_hunk_header(ecbdata, line, len);
1202                if (line[len-1] != '\n')
1203                        putc('\n', ecbdata->opt->file);
1204                return;
1205        }
1206
1207        if (len < 1) {
1208                emit_line(ecbdata->opt, reset, reset, line, len);
1209                if (ecbdata->diff_words
1210                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1211                        fputs("~\n", ecbdata->opt->file);
1212                return;
1213        }
1214
1215        if (ecbdata->diff_words) {
1216                if (line[0] == '-') {
1217                        diff_words_append(line, len,
1218                                          &ecbdata->diff_words->minus);
1219                        return;
1220                } else if (line[0] == '+') {
1221                        diff_words_append(line, len,
1222                                          &ecbdata->diff_words->plus);
1223                        return;
1224                } else if (starts_with(line, "\\ ")) {
1225                        /*
1226                         * Eat the "no newline at eof" marker as if we
1227                         * saw a "+" or "-" line with nothing on it,
1228                         * and return without diff_words_flush() to
1229                         * defer processing. If this is the end of
1230                         * preimage, more "+" lines may come after it.
1231                         */
1232                        return;
1233                }
1234                diff_words_flush(ecbdata);
1235                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1236                        emit_line(ecbdata->opt, context, reset, line, len);
1237                        fputs("~\n", ecbdata->opt->file);
1238                } else {
1239                        /*
1240                         * Skip the prefix character, if any.  With
1241                         * diff_suppress_blank_empty, there may be
1242                         * none.
1243                         */
1244                        if (line[0] != '\n') {
1245                              line++;
1246                              len--;
1247                        }
1248                        emit_line(ecbdata->opt, context, reset, line, len);
1249                }
1250                return;
1251        }
1252
1253        if (line[0] != '+') {
1254                const char *color =
1255                        diff_get_color(ecbdata->color_diff,
1256                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_CONTEXT);
1257                ecbdata->lno_in_preimage++;
1258                if (line[0] == ' ')
1259                        ecbdata->lno_in_postimage++;
1260                emit_line(ecbdata->opt, color, reset, line, len);
1261        } else {
1262                ecbdata->lno_in_postimage++;
1263                emit_add_line(reset, ecbdata, line + 1, len - 1);
1264        }
1265}
1266
1267static char *pprint_rename(const char *a, const char *b)
1268{
1269        const char *old = a;
1270        const char *new = b;
1271        struct strbuf name = STRBUF_INIT;
1272        int pfx_length, sfx_length;
1273        int pfx_adjust_for_slash;
1274        int len_a = strlen(a);
1275        int len_b = strlen(b);
1276        int a_midlen, b_midlen;
1277        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1278        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1279
1280        if (qlen_a || qlen_b) {
1281                quote_c_style(a, &name, NULL, 0);
1282                strbuf_addstr(&name, " => ");
1283                quote_c_style(b, &name, NULL, 0);
1284                return strbuf_detach(&name, NULL);
1285        }
1286
1287        /* Find common prefix */
1288        pfx_length = 0;
1289        while (*old && *new && *old == *new) {
1290                if (*old == '/')
1291                        pfx_length = old - a + 1;
1292                old++;
1293                new++;
1294        }
1295
1296        /* Find common suffix */
1297        old = a + len_a;
1298        new = b + len_b;
1299        sfx_length = 0;
1300        /*
1301         * If there is a common prefix, it must end in a slash.  In
1302         * that case we let this loop run 1 into the prefix to see the
1303         * same slash.
1304         *
1305         * If there is no common prefix, we cannot do this as it would
1306         * underrun the input strings.
1307         */
1308        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1309        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1310               b + pfx_length - pfx_adjust_for_slash <= new &&
1311               *old == *new) {
1312                if (*old == '/')
1313                        sfx_length = len_a - (old - a);
1314                old--;
1315                new--;
1316        }
1317
1318        /*
1319         * pfx{mid-a => mid-b}sfx
1320         * {pfx-a => pfx-b}sfx
1321         * pfx{sfx-a => sfx-b}
1322         * name-a => name-b
1323         */
1324        a_midlen = len_a - pfx_length - sfx_length;
1325        b_midlen = len_b - pfx_length - sfx_length;
1326        if (a_midlen < 0)
1327                a_midlen = 0;
1328        if (b_midlen < 0)
1329                b_midlen = 0;
1330
1331        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1332        if (pfx_length + sfx_length) {
1333                strbuf_add(&name, a, pfx_length);
1334                strbuf_addch(&name, '{');
1335        }
1336        strbuf_add(&name, a + pfx_length, a_midlen);
1337        strbuf_addstr(&name, " => ");
1338        strbuf_add(&name, b + pfx_length, b_midlen);
1339        if (pfx_length + sfx_length) {
1340                strbuf_addch(&name, '}');
1341                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1342        }
1343        return strbuf_detach(&name, NULL);
1344}
1345
1346struct diffstat_t {
1347        int nr;
1348        int alloc;
1349        struct diffstat_file {
1350                char *from_name;
1351                char *name;
1352                char *print_name;
1353                unsigned is_unmerged:1;
1354                unsigned is_binary:1;
1355                unsigned is_renamed:1;
1356                unsigned is_interesting:1;
1357                uintmax_t added, deleted;
1358        } **files;
1359};
1360
1361static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1362                                          const char *name_a,
1363                                          const char *name_b)
1364{
1365        struct diffstat_file *x;
1366        x = xcalloc(1, sizeof(*x));
1367        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1368        diffstat->files[diffstat->nr++] = x;
1369        if (name_b) {
1370                x->from_name = xstrdup(name_a);
1371                x->name = xstrdup(name_b);
1372                x->is_renamed = 1;
1373        }
1374        else {
1375                x->from_name = NULL;
1376                x->name = xstrdup(name_a);
1377        }
1378        return x;
1379}
1380
1381static void diffstat_consume(void *priv, char *line, unsigned long len)
1382{
1383        struct diffstat_t *diffstat = priv;
1384        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1385
1386        if (line[0] == '+')
1387                x->added++;
1388        else if (line[0] == '-')
1389                x->deleted++;
1390}
1391
1392const char mime_boundary_leader[] = "------------";
1393
1394static int scale_linear(int it, int width, int max_change)
1395{
1396        if (!it)
1397                return 0;
1398        /*
1399         * make sure that at least one '-' or '+' is printed if
1400         * there is any change to this path. The easiest way is to
1401         * scale linearly as if the alloted width is one column shorter
1402         * than it is, and then add 1 to the result.
1403         */
1404        return 1 + (it * (width - 1) / max_change);
1405}
1406
1407static void show_name(FILE *file,
1408                      const char *prefix, const char *name, int len)
1409{
1410        fprintf(file, " %s%-*s |", prefix, len, name);
1411}
1412
1413static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1414{
1415        if (cnt <= 0)
1416                return;
1417        fprintf(file, "%s", set);
1418        while (cnt--)
1419                putc(ch, file);
1420        fprintf(file, "%s", reset);
1421}
1422
1423static void fill_print_name(struct diffstat_file *file)
1424{
1425        char *pname;
1426
1427        if (file->print_name)
1428                return;
1429
1430        if (!file->is_renamed) {
1431                struct strbuf buf = STRBUF_INIT;
1432                if (quote_c_style(file->name, &buf, NULL, 0)) {
1433                        pname = strbuf_detach(&buf, NULL);
1434                } else {
1435                        pname = file->name;
1436                        strbuf_release(&buf);
1437                }
1438        } else {
1439                pname = pprint_rename(file->from_name, file->name);
1440        }
1441        file->print_name = pname;
1442}
1443
1444int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1445{
1446        struct strbuf sb = STRBUF_INIT;
1447        int ret;
1448
1449        if (!files) {
1450                assert(insertions == 0 && deletions == 0);
1451                return fprintf(fp, "%s\n", " 0 files changed");
1452        }
1453
1454        strbuf_addf(&sb,
1455                    (files == 1) ? " %d file changed" : " %d files changed",
1456                    files);
1457
1458        /*
1459         * For binary diff, the caller may want to print "x files
1460         * changed" with insertions == 0 && deletions == 0.
1461         *
1462         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1463         * is probably less confusing (i.e skip over "2 files changed
1464         * but nothing about added/removed lines? Is this a bug in Git?").
1465         */
1466        if (insertions || deletions == 0) {
1467                strbuf_addf(&sb,
1468                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1469                            insertions);
1470        }
1471
1472        if (deletions || insertions == 0) {
1473                strbuf_addf(&sb,
1474                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1475                            deletions);
1476        }
1477        strbuf_addch(&sb, '\n');
1478        ret = fputs(sb.buf, fp);
1479        strbuf_release(&sb);
1480        return ret;
1481}
1482
1483static void show_stats(struct diffstat_t *data, struct diff_options *options)
1484{
1485        int i, len, add, del, adds = 0, dels = 0;
1486        uintmax_t max_change = 0, max_len = 0;
1487        int total_files = data->nr, count;
1488        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1489        const char *reset, *add_c, *del_c;
1490        const char *line_prefix = "";
1491        int extra_shown = 0;
1492
1493        if (data->nr == 0)
1494                return;
1495
1496        line_prefix = diff_line_prefix(options);
1497        count = options->stat_count ? options->stat_count : data->nr;
1498
1499        reset = diff_get_color_opt(options, DIFF_RESET);
1500        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1501        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1502
1503        /*
1504         * Find the longest filename and max number of changes
1505         */
1506        for (i = 0; (i < count) && (i < data->nr); i++) {
1507                struct diffstat_file *file = data->files[i];
1508                uintmax_t change = file->added + file->deleted;
1509
1510                if (!file->is_interesting && (change == 0)) {
1511                        count++; /* not shown == room for one more */
1512                        continue;
1513                }
1514                fill_print_name(file);
1515                len = strlen(file->print_name);
1516                if (max_len < len)
1517                        max_len = len;
1518
1519                if (file->is_unmerged) {
1520                        /* "Unmerged" is 8 characters */
1521                        bin_width = bin_width < 8 ? 8 : bin_width;
1522                        continue;
1523                }
1524                if (file->is_binary) {
1525                        /* "Bin XXX -> YYY bytes" */
1526                        int w = 14 + decimal_width(file->added)
1527                                + decimal_width(file->deleted);
1528                        bin_width = bin_width < w ? w : bin_width;
1529                        /* Display change counts aligned with "Bin" */
1530                        number_width = 3;
1531                        continue;
1532                }
1533
1534                if (max_change < change)
1535                        max_change = change;
1536        }
1537        count = i; /* where we can stop scanning in data->files[] */
1538
1539        /*
1540         * We have width = stat_width or term_columns() columns total.
1541         * We want a maximum of min(max_len, stat_name_width) for the name part.
1542         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1543         * We also need 1 for " " and 4 + decimal_width(max_change)
1544         * for " | NNNN " and one the empty column at the end, altogether
1545         * 6 + decimal_width(max_change).
1546         *
1547         * If there's not enough space, we will use the smaller of
1548         * stat_name_width (if set) and 5/8*width for the filename,
1549         * and the rest for constant elements + graph part, but no more
1550         * than stat_graph_width for the graph part.
1551         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1552         * for the standard terminal size).
1553         *
1554         * In other words: stat_width limits the maximum width, and
1555         * stat_name_width fixes the maximum width of the filename,
1556         * and is also used to divide available columns if there
1557         * aren't enough.
1558         *
1559         * Binary files are displayed with "Bin XXX -> YYY bytes"
1560         * instead of the change count and graph. This part is treated
1561         * similarly to the graph part, except that it is not
1562         * "scaled". If total width is too small to accommodate the
1563         * guaranteed minimum width of the filename part and the
1564         * separators and this message, this message will "overflow"
1565         * making the line longer than the maximum width.
1566         */
1567
1568        if (options->stat_width == -1)
1569                width = term_columns() - options->output_prefix_length;
1570        else
1571                width = options->stat_width ? options->stat_width : 80;
1572        number_width = decimal_width(max_change) > number_width ?
1573                decimal_width(max_change) : number_width;
1574
1575        if (options->stat_graph_width == -1)
1576                options->stat_graph_width = diff_stat_graph_width;
1577
1578        /*
1579         * Guarantee 3/8*16==6 for the graph part
1580         * and 5/8*16==10 for the filename part
1581         */
1582        if (width < 16 + 6 + number_width)
1583                width = 16 + 6 + number_width;
1584
1585        /*
1586         * First assign sizes that are wanted, ignoring available width.
1587         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1588         * starting from "XXX" should fit in graph_width.
1589         */
1590        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1591        if (options->stat_graph_width &&
1592            options->stat_graph_width < graph_width)
1593                graph_width = options->stat_graph_width;
1594
1595        name_width = (options->stat_name_width > 0 &&
1596                      options->stat_name_width < max_len) ?
1597                options->stat_name_width : max_len;
1598
1599        /*
1600         * Adjust adjustable widths not to exceed maximum width
1601         */
1602        if (name_width + number_width + 6 + graph_width > width) {
1603                if (graph_width > width * 3/8 - number_width - 6) {
1604                        graph_width = width * 3/8 - number_width - 6;
1605                        if (graph_width < 6)
1606                                graph_width = 6;
1607                }
1608
1609                if (options->stat_graph_width &&
1610                    graph_width > options->stat_graph_width)
1611                        graph_width = options->stat_graph_width;
1612                if (name_width > width - number_width - 6 - graph_width)
1613                        name_width = width - number_width - 6 - graph_width;
1614                else
1615                        graph_width = width - number_width - 6 - name_width;
1616        }
1617
1618        /*
1619         * From here name_width is the width of the name area,
1620         * and graph_width is the width of the graph area.
1621         * max_change is used to scale graph properly.
1622         */
1623        for (i = 0; i < count; i++) {
1624                const char *prefix = "";
1625                struct diffstat_file *file = data->files[i];
1626                char *name = file->print_name;
1627                uintmax_t added = file->added;
1628                uintmax_t deleted = file->deleted;
1629                int name_len;
1630
1631                if (!file->is_interesting && (added + deleted == 0))
1632                        continue;
1633
1634                /*
1635                 * "scale" the filename
1636                 */
1637                len = name_width;
1638                name_len = strlen(name);
1639                if (name_width < name_len) {
1640                        char *slash;
1641                        prefix = "...";
1642                        len -= 3;
1643                        name += name_len - len;
1644                        slash = strchr(name, '/');
1645                        if (slash)
1646                                name = slash;
1647                }
1648
1649                if (file->is_binary) {
1650                        fprintf(options->file, "%s", line_prefix);
1651                        show_name(options->file, prefix, name, len);
1652                        fprintf(options->file, " %*s", number_width, "Bin");
1653                        if (!added && !deleted) {
1654                                putc('\n', options->file);
1655                                continue;
1656                        }
1657                        fprintf(options->file, " %s%"PRIuMAX"%s",
1658                                del_c, deleted, reset);
1659                        fprintf(options->file, " -> ");
1660                        fprintf(options->file, "%s%"PRIuMAX"%s",
1661                                add_c, added, reset);
1662                        fprintf(options->file, " bytes");
1663                        fprintf(options->file, "\n");
1664                        continue;
1665                }
1666                else if (file->is_unmerged) {
1667                        fprintf(options->file, "%s", line_prefix);
1668                        show_name(options->file, prefix, name, len);
1669                        fprintf(options->file, " Unmerged\n");
1670                        continue;
1671                }
1672
1673                /*
1674                 * scale the add/delete
1675                 */
1676                add = added;
1677                del = deleted;
1678
1679                if (graph_width <= max_change) {
1680                        int total = scale_linear(add + del, graph_width, max_change);
1681                        if (total < 2 && add && del)
1682                                /* width >= 2 due to the sanity check */
1683                                total = 2;
1684                        if (add < del) {
1685                                add = scale_linear(add, graph_width, max_change);
1686                                del = total - add;
1687                        } else {
1688                                del = scale_linear(del, graph_width, max_change);
1689                                add = total - del;
1690                        }
1691                }
1692                fprintf(options->file, "%s", line_prefix);
1693                show_name(options->file, prefix, name, len);
1694                fprintf(options->file, " %*"PRIuMAX"%s",
1695                        number_width, added + deleted,
1696                        added + deleted ? " " : "");
1697                show_graph(options->file, '+', add, add_c, reset);
1698                show_graph(options->file, '-', del, del_c, reset);
1699                fprintf(options->file, "\n");
1700        }
1701
1702        for (i = 0; i < data->nr; i++) {
1703                struct diffstat_file *file = data->files[i];
1704                uintmax_t added = file->added;
1705                uintmax_t deleted = file->deleted;
1706
1707                if (file->is_unmerged ||
1708                    (!file->is_interesting && (added + deleted == 0))) {
1709                        total_files--;
1710                        continue;
1711                }
1712
1713                if (!file->is_binary) {
1714                        adds += added;
1715                        dels += deleted;
1716                }
1717                if (i < count)
1718                        continue;
1719                if (!extra_shown)
1720                        fprintf(options->file, "%s ...\n", line_prefix);
1721                extra_shown = 1;
1722        }
1723        fprintf(options->file, "%s", line_prefix);
1724        print_stat_summary(options->file, total_files, adds, dels);
1725}
1726
1727static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1728{
1729        int i, adds = 0, dels = 0, total_files = data->nr;
1730
1731        if (data->nr == 0)
1732                return;
1733
1734        for (i = 0; i < data->nr; i++) {
1735                int added = data->files[i]->added;
1736                int deleted= data->files[i]->deleted;
1737
1738                if (data->files[i]->is_unmerged ||
1739                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1740                        total_files--;
1741                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1742                        adds += added;
1743                        dels += deleted;
1744                }
1745        }
1746        fprintf(options->file, "%s", diff_line_prefix(options));
1747        print_stat_summary(options->file, total_files, adds, dels);
1748}
1749
1750static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1751{
1752        int i;
1753
1754        if (data->nr == 0)
1755                return;
1756
1757        for (i = 0; i < data->nr; i++) {
1758                struct diffstat_file *file = data->files[i];
1759
1760                fprintf(options->file, "%s", diff_line_prefix(options));
1761
1762                if (file->is_binary)
1763                        fprintf(options->file, "-\t-\t");
1764                else
1765                        fprintf(options->file,
1766                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1767                                file->added, file->deleted);
1768                if (options->line_termination) {
1769                        fill_print_name(file);
1770                        if (!file->is_renamed)
1771                                write_name_quoted(file->name, options->file,
1772                                                  options->line_termination);
1773                        else {
1774                                fputs(file->print_name, options->file);
1775                                putc(options->line_termination, options->file);
1776                        }
1777                } else {
1778                        if (file->is_renamed) {
1779                                putc('\0', options->file);
1780                                write_name_quoted(file->from_name, options->file, '\0');
1781                        }
1782                        write_name_quoted(file->name, options->file, '\0');
1783                }
1784        }
1785}
1786
1787struct dirstat_file {
1788        const char *name;
1789        unsigned long changed;
1790};
1791
1792struct dirstat_dir {
1793        struct dirstat_file *files;
1794        int alloc, nr, permille, cumulative;
1795};
1796
1797static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1798                unsigned long changed, const char *base, int baselen)
1799{
1800        unsigned long this_dir = 0;
1801        unsigned int sources = 0;
1802        const char *line_prefix = diff_line_prefix(opt);
1803
1804        while (dir->nr) {
1805                struct dirstat_file *f = dir->files;
1806                int namelen = strlen(f->name);
1807                unsigned long this;
1808                char *slash;
1809
1810                if (namelen < baselen)
1811                        break;
1812                if (memcmp(f->name, base, baselen))
1813                        break;
1814                slash = strchr(f->name + baselen, '/');
1815                if (slash) {
1816                        int newbaselen = slash + 1 - f->name;
1817                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1818                        sources++;
1819                } else {
1820                        this = f->changed;
1821                        dir->files++;
1822                        dir->nr--;
1823                        sources += 2;
1824                }
1825                this_dir += this;
1826        }
1827
1828        /*
1829         * We don't report dirstat's for
1830         *  - the top level
1831         *  - or cases where everything came from a single directory
1832         *    under this directory (sources == 1).
1833         */
1834        if (baselen && sources != 1) {
1835                if (this_dir) {
1836                        int permille = this_dir * 1000 / changed;
1837                        if (permille >= dir->permille) {
1838                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1839                                        permille / 10, permille % 10, baselen, base);
1840                                if (!dir->cumulative)
1841                                        return 0;
1842                        }
1843                }
1844        }
1845        return this_dir;
1846}
1847
1848static int dirstat_compare(const void *_a, const void *_b)
1849{
1850        const struct dirstat_file *a = _a;
1851        const struct dirstat_file *b = _b;
1852        return strcmp(a->name, b->name);
1853}
1854
1855static void show_dirstat(struct diff_options *options)
1856{
1857        int i;
1858        unsigned long changed;
1859        struct dirstat_dir dir;
1860        struct diff_queue_struct *q = &diff_queued_diff;
1861
1862        dir.files = NULL;
1863        dir.alloc = 0;
1864        dir.nr = 0;
1865        dir.permille = options->dirstat_permille;
1866        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1867
1868        changed = 0;
1869        for (i = 0; i < q->nr; i++) {
1870                struct diff_filepair *p = q->queue[i];
1871                const char *name;
1872                unsigned long copied, added, damage;
1873                int content_changed;
1874
1875                name = p->two->path ? p->two->path : p->one->path;
1876
1877                if (p->one->sha1_valid && p->two->sha1_valid)
1878                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1879                else
1880                        content_changed = 1;
1881
1882                if (!content_changed) {
1883                        /*
1884                         * The SHA1 has not changed, so pre-/post-content is
1885                         * identical. We can therefore skip looking at the
1886                         * file contents altogether.
1887                         */
1888                        damage = 0;
1889                        goto found_damage;
1890                }
1891
1892                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1893                        /*
1894                         * In --dirstat-by-file mode, we don't really need to
1895                         * look at the actual file contents at all.
1896                         * The fact that the SHA1 changed is enough for us to
1897                         * add this file to the list of results
1898                         * (with each file contributing equal damage).
1899                         */
1900                        damage = 1;
1901                        goto found_damage;
1902                }
1903
1904                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1905                        diff_populate_filespec(p->one, 0);
1906                        diff_populate_filespec(p->two, 0);
1907                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1908                                               &copied, &added);
1909                        diff_free_filespec_data(p->one);
1910                        diff_free_filespec_data(p->two);
1911                } else if (DIFF_FILE_VALID(p->one)) {
1912                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1913                        copied = added = 0;
1914                        diff_free_filespec_data(p->one);
1915                } else if (DIFF_FILE_VALID(p->two)) {
1916                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1917                        copied = 0;
1918                        added = p->two->size;
1919                        diff_free_filespec_data(p->two);
1920                } else
1921                        continue;
1922
1923                /*
1924                 * Original minus copied is the removed material,
1925                 * added is the new material.  They are both damages
1926                 * made to the preimage.
1927                 * If the resulting damage is zero, we know that
1928                 * diffcore_count_changes() considers the two entries to
1929                 * be identical, but since content_changed is true, we
1930                 * know that there must have been _some_ kind of change,
1931                 * so we force all entries to have damage > 0.
1932                 */
1933                damage = (p->one->size - copied) + added;
1934                if (!damage)
1935                        damage = 1;
1936
1937found_damage:
1938                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1939                dir.files[dir.nr].name = name;
1940                dir.files[dir.nr].changed = damage;
1941                changed += damage;
1942                dir.nr++;
1943        }
1944
1945        /* This can happen even with many files, if everything was renames */
1946        if (!changed)
1947                return;
1948
1949        /* Show all directories with more than x% of the changes */
1950        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1951        gather_dirstat(options, &dir, changed, "", 0);
1952}
1953
1954static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1955{
1956        int i;
1957        unsigned long changed;
1958        struct dirstat_dir dir;
1959
1960        if (data->nr == 0)
1961                return;
1962
1963        dir.files = NULL;
1964        dir.alloc = 0;
1965        dir.nr = 0;
1966        dir.permille = options->dirstat_permille;
1967        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1968
1969        changed = 0;
1970        for (i = 0; i < data->nr; i++) {
1971                struct diffstat_file *file = data->files[i];
1972                unsigned long damage = file->added + file->deleted;
1973                if (file->is_binary)
1974                        /*
1975                         * binary files counts bytes, not lines. Must find some
1976                         * way to normalize binary bytes vs. textual lines.
1977                         * The following heuristic assumes that there are 64
1978                         * bytes per "line".
1979                         * This is stupid and ugly, but very cheap...
1980                         */
1981                        damage = (damage + 63) / 64;
1982                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1983                dir.files[dir.nr].name = file->name;
1984                dir.files[dir.nr].changed = damage;
1985                changed += damage;
1986                dir.nr++;
1987        }
1988
1989        /* This can happen even with many files, if everything was renames */
1990        if (!changed)
1991                return;
1992
1993        /* Show all directories with more than x% of the changes */
1994        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1995        gather_dirstat(options, &dir, changed, "", 0);
1996}
1997
1998static void free_diffstat_info(struct diffstat_t *diffstat)
1999{
2000        int i;
2001        for (i = 0; i < diffstat->nr; i++) {
2002                struct diffstat_file *f = diffstat->files[i];
2003                if (f->name != f->print_name)
2004                        free(f->print_name);
2005                free(f->name);
2006                free(f->from_name);
2007                free(f);
2008        }
2009        free(diffstat->files);
2010}
2011
2012struct checkdiff_t {
2013        const char *filename;
2014        int lineno;
2015        int conflict_marker_size;
2016        struct diff_options *o;
2017        unsigned ws_rule;
2018        unsigned status;
2019};
2020
2021static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2022{
2023        char firstchar;
2024        int cnt;
2025
2026        if (len < marker_size + 1)
2027                return 0;
2028        firstchar = line[0];
2029        switch (firstchar) {
2030        case '=': case '>': case '<': case '|':
2031                break;
2032        default:
2033                return 0;
2034        }
2035        for (cnt = 1; cnt < marker_size; cnt++)
2036                if (line[cnt] != firstchar)
2037                        return 0;
2038        /* line[1] thru line[marker_size-1] are same as firstchar */
2039        if (len < marker_size + 1 || !isspace(line[marker_size]))
2040                return 0;
2041        return 1;
2042}
2043
2044static void checkdiff_consume(void *priv, char *line, unsigned long len)
2045{
2046        struct checkdiff_t *data = priv;
2047        int marker_size = data->conflict_marker_size;
2048        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2049        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2050        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2051        char *err;
2052        const char *line_prefix;
2053
2054        assert(data->o);
2055        line_prefix = diff_line_prefix(data->o);
2056
2057        if (line[0] == '+') {
2058                unsigned bad;
2059                data->lineno++;
2060                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2061                        data->status |= 1;
2062                        fprintf(data->o->file,
2063                                "%s%s:%d: leftover conflict marker\n",
2064                                line_prefix, data->filename, data->lineno);
2065                }
2066                bad = ws_check(line + 1, len - 1, data->ws_rule);
2067                if (!bad)
2068                        return;
2069                data->status |= bad;
2070                err = whitespace_error_string(bad);
2071                fprintf(data->o->file, "%s%s:%d: %s.\n",
2072                        line_prefix, data->filename, data->lineno, err);
2073                free(err);
2074                emit_line(data->o, set, reset, line, 1);
2075                ws_check_emit(line + 1, len - 1, data->ws_rule,
2076                              data->o->file, set, reset, ws);
2077        } else if (line[0] == ' ') {
2078                data->lineno++;
2079        } else if (line[0] == '@') {
2080                char *plus = strchr(line, '+');
2081                if (plus)
2082                        data->lineno = strtol(plus, NULL, 10) - 1;
2083                else
2084                        die("invalid diff");
2085        }
2086}
2087
2088static unsigned char *deflate_it(char *data,
2089                                 unsigned long size,
2090                                 unsigned long *result_size)
2091{
2092        int bound;
2093        unsigned char *deflated;
2094        git_zstream stream;
2095
2096        git_deflate_init(&stream, zlib_compression_level);
2097        bound = git_deflate_bound(&stream, size);
2098        deflated = xmalloc(bound);
2099        stream.next_out = deflated;
2100        stream.avail_out = bound;
2101
2102        stream.next_in = (unsigned char *)data;
2103        stream.avail_in = size;
2104        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2105                ; /* nothing */
2106        git_deflate_end(&stream);
2107        *result_size = stream.total_out;
2108        return deflated;
2109}
2110
2111static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2112                                  const char *prefix)
2113{
2114        void *cp;
2115        void *delta;
2116        void *deflated;
2117        void *data;
2118        unsigned long orig_size;
2119        unsigned long delta_size;
2120        unsigned long deflate_size;
2121        unsigned long data_size;
2122
2123        /* We could do deflated delta, or we could do just deflated two,
2124         * whichever is smaller.
2125         */
2126        delta = NULL;
2127        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2128        if (one->size && two->size) {
2129                delta = diff_delta(one->ptr, one->size,
2130                                   two->ptr, two->size,
2131                                   &delta_size, deflate_size);
2132                if (delta) {
2133                        void *to_free = delta;
2134                        orig_size = delta_size;
2135                        delta = deflate_it(delta, delta_size, &delta_size);
2136                        free(to_free);
2137                }
2138        }
2139
2140        if (delta && delta_size < deflate_size) {
2141                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2142                free(deflated);
2143                data = delta;
2144                data_size = delta_size;
2145        }
2146        else {
2147                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2148                free(delta);
2149                data = deflated;
2150                data_size = deflate_size;
2151        }
2152
2153        /* emit data encoded in base85 */
2154        cp = data;
2155        while (data_size) {
2156                int bytes = (52 < data_size) ? 52 : data_size;
2157                char line[70];
2158                data_size -= bytes;
2159                if (bytes <= 26)
2160                        line[0] = bytes + 'A' - 1;
2161                else
2162                        line[0] = bytes - 26 + 'a' - 1;
2163                encode_85(line + 1, cp, bytes);
2164                cp = (char *) cp + bytes;
2165                fprintf(file, "%s", prefix);
2166                fputs(line, file);
2167                fputc('\n', file);
2168        }
2169        fprintf(file, "%s\n", prefix);
2170        free(data);
2171}
2172
2173static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2174                             const char *prefix)
2175{
2176        fprintf(file, "%sGIT binary patch\n", prefix);
2177        emit_binary_diff_body(file, one, two, prefix);
2178        emit_binary_diff_body(file, two, one, prefix);
2179}
2180
2181int diff_filespec_is_binary(struct diff_filespec *one)
2182{
2183        if (one->is_binary == -1) {
2184                diff_filespec_load_driver(one);
2185                if (one->driver->binary != -1)
2186                        one->is_binary = one->driver->binary;
2187                else {
2188                        if (!one->data && DIFF_FILE_VALID(one))
2189                                diff_populate_filespec(one, CHECK_BINARY);
2190                        if (one->is_binary == -1 && one->data)
2191                                one->is_binary = buffer_is_binary(one->data,
2192                                                one->size);
2193                        if (one->is_binary == -1)
2194                                one->is_binary = 0;
2195                }
2196        }
2197        return one->is_binary;
2198}
2199
2200static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2201{
2202        diff_filespec_load_driver(one);
2203        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2204}
2205
2206void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2207{
2208        if (!options->a_prefix)
2209                options->a_prefix = a;
2210        if (!options->b_prefix)
2211                options->b_prefix = b;
2212}
2213
2214struct userdiff_driver *get_textconv(struct diff_filespec *one)
2215{
2216        if (!DIFF_FILE_VALID(one))
2217                return NULL;
2218
2219        diff_filespec_load_driver(one);
2220        return userdiff_get_textconv(one->driver);
2221}
2222
2223static void builtin_diff(const char *name_a,
2224                         const char *name_b,
2225                         struct diff_filespec *one,
2226                         struct diff_filespec *two,
2227                         const char *xfrm_msg,
2228                         int must_show_header,
2229                         struct diff_options *o,
2230                         int complete_rewrite)
2231{
2232        mmfile_t mf1, mf2;
2233        const char *lbl[2];
2234        char *a_one, *b_two;
2235        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2236        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2237        const char *a_prefix, *b_prefix;
2238        struct userdiff_driver *textconv_one = NULL;
2239        struct userdiff_driver *textconv_two = NULL;
2240        struct strbuf header = STRBUF_INIT;
2241        const char *line_prefix = diff_line_prefix(o);
2242
2243        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2244                        (!one->mode || S_ISGITLINK(one->mode)) &&
2245                        (!two->mode || S_ISGITLINK(two->mode))) {
2246                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2247                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2248                show_submodule_summary(o->file, one->path ? one->path : two->path,
2249                                line_prefix,
2250                                one->sha1, two->sha1, two->dirty_submodule,
2251                                meta, del, add, reset);
2252                return;
2253        }
2254
2255        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2256                textconv_one = get_textconv(one);
2257                textconv_two = get_textconv(two);
2258        }
2259
2260        diff_set_mnemonic_prefix(o, "a/", "b/");
2261        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2262                a_prefix = o->b_prefix;
2263                b_prefix = o->a_prefix;
2264        } else {
2265                a_prefix = o->a_prefix;
2266                b_prefix = o->b_prefix;
2267        }
2268
2269        /* Never use a non-valid filename anywhere if at all possible */
2270        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2271        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2272
2273        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2274        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2275        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2276        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2277        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2278        if (lbl[0][0] == '/') {
2279                /* /dev/null */
2280                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2281                if (xfrm_msg)
2282                        strbuf_addstr(&header, xfrm_msg);
2283                must_show_header = 1;
2284        }
2285        else if (lbl[1][0] == '/') {
2286                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2287                if (xfrm_msg)
2288                        strbuf_addstr(&header, xfrm_msg);
2289                must_show_header = 1;
2290        }
2291        else {
2292                if (one->mode != two->mode) {
2293                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2294                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2295                        must_show_header = 1;
2296                }
2297                if (xfrm_msg)
2298                        strbuf_addstr(&header, xfrm_msg);
2299
2300                /*
2301                 * we do not run diff between different kind
2302                 * of objects.
2303                 */
2304                if ((one->mode ^ two->mode) & S_IFMT)
2305                        goto free_ab_and_return;
2306                if (complete_rewrite &&
2307                    (textconv_one || !diff_filespec_is_binary(one)) &&
2308                    (textconv_two || !diff_filespec_is_binary(two))) {
2309                        fprintf(o->file, "%s", header.buf);
2310                        strbuf_reset(&header);
2311                        emit_rewrite_diff(name_a, name_b, one, two,
2312                                                textconv_one, textconv_two, o);
2313                        o->found_changes = 1;
2314                        goto free_ab_and_return;
2315                }
2316        }
2317
2318        if (o->irreversible_delete && lbl[1][0] == '/') {
2319                fprintf(o->file, "%s", header.buf);
2320                strbuf_reset(&header);
2321                goto free_ab_and_return;
2322        } else if (!DIFF_OPT_TST(o, TEXT) &&
2323            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2324              (!textconv_two && diff_filespec_is_binary(two)) )) {
2325                if (!one->data && !two->data &&
2326                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2327                    !DIFF_OPT_TST(o, BINARY)) {
2328                        if (!hashcmp(one->sha1, two->sha1)) {
2329                                if (must_show_header)
2330                                        fprintf(o->file, "%s", header.buf);
2331                                goto free_ab_and_return;
2332                        }
2333                        fprintf(o->file, "%s", header.buf);
2334                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2335                                line_prefix, lbl[0], lbl[1]);
2336                        goto free_ab_and_return;
2337                }
2338                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2339                        die("unable to read files to diff");
2340                /* Quite common confusing case */
2341                if (mf1.size == mf2.size &&
2342                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2343                        if (must_show_header)
2344                                fprintf(o->file, "%s", header.buf);
2345                        goto free_ab_and_return;
2346                }
2347                fprintf(o->file, "%s", header.buf);
2348                strbuf_reset(&header);
2349                if (DIFF_OPT_TST(o, BINARY))
2350                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2351                else
2352                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2353                                line_prefix, lbl[0], lbl[1]);
2354                o->found_changes = 1;
2355        } else {
2356                /* Crazy xdl interfaces.. */
2357                const char *diffopts = getenv("GIT_DIFF_OPTS");
2358                const char *v;
2359                xpparam_t xpp;
2360                xdemitconf_t xecfg;
2361                struct emit_callback ecbdata;
2362                const struct userdiff_funcname *pe;
2363
2364                if (must_show_header) {
2365                        fprintf(o->file, "%s", header.buf);
2366                        strbuf_reset(&header);
2367                }
2368
2369                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2370                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2371
2372                pe = diff_funcname_pattern(one);
2373                if (!pe)
2374                        pe = diff_funcname_pattern(two);
2375
2376                memset(&xpp, 0, sizeof(xpp));
2377                memset(&xecfg, 0, sizeof(xecfg));
2378                memset(&ecbdata, 0, sizeof(ecbdata));
2379                ecbdata.label_path = lbl;
2380                ecbdata.color_diff = want_color(o->use_color);
2381                ecbdata.found_changesp = &o->found_changes;
2382                ecbdata.ws_rule = whitespace_rule(name_b);
2383                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2384                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2385                ecbdata.opt = o;
2386                ecbdata.header = header.len ? &header : NULL;
2387                xpp.flags = o->xdl_opts;
2388                xecfg.ctxlen = o->context;
2389                xecfg.interhunkctxlen = o->interhunkcontext;
2390                xecfg.flags = XDL_EMIT_FUNCNAMES;
2391                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2392                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2393                if (pe)
2394                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2395                if (!diffopts)
2396                        ;
2397                else if (skip_prefix(diffopts, "--unified=", &v))
2398                        xecfg.ctxlen = strtoul(v, NULL, 10);
2399                else if (skip_prefix(diffopts, "-u", &v))
2400                        xecfg.ctxlen = strtoul(v, NULL, 10);
2401                if (o->word_diff)
2402                        init_diff_words_data(&ecbdata, o, one, two);
2403                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2404                              &xpp, &xecfg);
2405                if (o->word_diff)
2406                        free_diff_words_data(&ecbdata);
2407                if (textconv_one)
2408                        free(mf1.ptr);
2409                if (textconv_two)
2410                        free(mf2.ptr);
2411                xdiff_clear_find_func(&xecfg);
2412        }
2413
2414 free_ab_and_return:
2415        strbuf_release(&header);
2416        diff_free_filespec_data(one);
2417        diff_free_filespec_data(two);
2418        free(a_one);
2419        free(b_two);
2420        return;
2421}
2422
2423static void builtin_diffstat(const char *name_a, const char *name_b,
2424                             struct diff_filespec *one,
2425                             struct diff_filespec *two,
2426                             struct diffstat_t *diffstat,
2427                             struct diff_options *o,
2428                             struct diff_filepair *p)
2429{
2430        mmfile_t mf1, mf2;
2431        struct diffstat_file *data;
2432        int same_contents;
2433        int complete_rewrite = 0;
2434
2435        if (!DIFF_PAIR_UNMERGED(p)) {
2436                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2437                        complete_rewrite = 1;
2438        }
2439
2440        data = diffstat_add(diffstat, name_a, name_b);
2441        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2442
2443        if (!one || !two) {
2444                data->is_unmerged = 1;
2445                return;
2446        }
2447
2448        same_contents = !hashcmp(one->sha1, two->sha1);
2449
2450        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2451                data->is_binary = 1;
2452                if (same_contents) {
2453                        data->added = 0;
2454                        data->deleted = 0;
2455                } else {
2456                        data->added = diff_filespec_size(two);
2457                        data->deleted = diff_filespec_size(one);
2458                }
2459        }
2460
2461        else if (complete_rewrite) {
2462                diff_populate_filespec(one, 0);
2463                diff_populate_filespec(two, 0);
2464                data->deleted = count_lines(one->data, one->size);
2465                data->added = count_lines(two->data, two->size);
2466        }
2467
2468        else if (!same_contents) {
2469                /* Crazy xdl interfaces.. */
2470                xpparam_t xpp;
2471                xdemitconf_t xecfg;
2472
2473                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2474                        die("unable to read files to diff");
2475
2476                memset(&xpp, 0, sizeof(xpp));
2477                memset(&xecfg, 0, sizeof(xecfg));
2478                xpp.flags = o->xdl_opts;
2479                xecfg.ctxlen = o->context;
2480                xecfg.interhunkctxlen = o->interhunkcontext;
2481                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2482                              &xpp, &xecfg);
2483        }
2484
2485        diff_free_filespec_data(one);
2486        diff_free_filespec_data(two);
2487}
2488
2489static void builtin_checkdiff(const char *name_a, const char *name_b,
2490                              const char *attr_path,
2491                              struct diff_filespec *one,
2492                              struct diff_filespec *two,
2493                              struct diff_options *o)
2494{
2495        mmfile_t mf1, mf2;
2496        struct checkdiff_t data;
2497
2498        if (!two)
2499                return;
2500
2501        memset(&data, 0, sizeof(data));
2502        data.filename = name_b ? name_b : name_a;
2503        data.lineno = 0;
2504        data.o = o;
2505        data.ws_rule = whitespace_rule(attr_path);
2506        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2507
2508        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2509                die("unable to read files to diff");
2510
2511        /*
2512         * All the other codepaths check both sides, but not checking
2513         * the "old" side here is deliberate.  We are checking the newly
2514         * introduced changes, and as long as the "new" side is text, we
2515         * can and should check what it introduces.
2516         */
2517        if (diff_filespec_is_binary(two))
2518                goto free_and_return;
2519        else {
2520                /* Crazy xdl interfaces.. */
2521                xpparam_t xpp;
2522                xdemitconf_t xecfg;
2523
2524                memset(&xpp, 0, sizeof(xpp));
2525                memset(&xecfg, 0, sizeof(xecfg));
2526                xecfg.ctxlen = 1; /* at least one context line */
2527                xpp.flags = 0;
2528                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2529                              &xpp, &xecfg);
2530
2531                if (data.ws_rule & WS_BLANK_AT_EOF) {
2532                        struct emit_callback ecbdata;
2533                        int blank_at_eof;
2534
2535                        ecbdata.ws_rule = data.ws_rule;
2536                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2537                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2538
2539                        if (blank_at_eof) {
2540                                static char *err;
2541                                if (!err)
2542                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2543                                fprintf(o->file, "%s:%d: %s.\n",
2544                                        data.filename, blank_at_eof, err);
2545                                data.status = 1; /* report errors */
2546                        }
2547                }
2548        }
2549 free_and_return:
2550        diff_free_filespec_data(one);
2551        diff_free_filespec_data(two);
2552        if (data.status)
2553                DIFF_OPT_SET(o, CHECK_FAILED);
2554}
2555
2556struct diff_filespec *alloc_filespec(const char *path)
2557{
2558        int namelen = strlen(path);
2559        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2560
2561        memset(spec, 0, sizeof(*spec));
2562        spec->path = (char *)(spec + 1);
2563        memcpy(spec->path, path, namelen+1);
2564        spec->count = 1;
2565        spec->is_binary = -1;
2566        return spec;
2567}
2568
2569void free_filespec(struct diff_filespec *spec)
2570{
2571        if (!--spec->count) {
2572                diff_free_filespec_data(spec);
2573                free(spec);
2574        }
2575}
2576
2577void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2578                   int sha1_valid, unsigned short mode)
2579{
2580        if (mode) {
2581                spec->mode = canon_mode(mode);
2582                hashcpy(spec->sha1, sha1);
2583                spec->sha1_valid = sha1_valid;
2584        }
2585}
2586
2587/*
2588 * Given a name and sha1 pair, if the index tells us the file in
2589 * the work tree has that object contents, return true, so that
2590 * prepare_temp_file() does not have to inflate and extract.
2591 */
2592static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2593{
2594        const struct cache_entry *ce;
2595        struct stat st;
2596        int pos, len;
2597
2598        /*
2599         * We do not read the cache ourselves here, because the
2600         * benchmark with my previous version that always reads cache
2601         * shows that it makes things worse for diff-tree comparing
2602         * two linux-2.6 kernel trees in an already checked out work
2603         * tree.  This is because most diff-tree comparisons deal with
2604         * only a small number of files, while reading the cache is
2605         * expensive for a large project, and its cost outweighs the
2606         * savings we get by not inflating the object to a temporary
2607         * file.  Practically, this code only helps when we are used
2608         * by diff-cache --cached, which does read the cache before
2609         * calling us.
2610         */
2611        if (!active_cache)
2612                return 0;
2613
2614        /* We want to avoid the working directory if our caller
2615         * doesn't need the data in a normal file, this system
2616         * is rather slow with its stat/open/mmap/close syscalls,
2617         * and the object is contained in a pack file.  The pack
2618         * is probably already open and will be faster to obtain
2619         * the data through than the working directory.  Loose
2620         * objects however would tend to be slower as they need
2621         * to be individually opened and inflated.
2622         */
2623        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2624                return 0;
2625
2626        len = strlen(name);
2627        pos = cache_name_pos(name, len);
2628        if (pos < 0)
2629                return 0;
2630        ce = active_cache[pos];
2631
2632        /*
2633         * This is not the sha1 we are looking for, or
2634         * unreusable because it is not a regular file.
2635         */
2636        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2637                return 0;
2638
2639        /*
2640         * If ce is marked as "assume unchanged", there is no
2641         * guarantee that work tree matches what we are looking for.
2642         */
2643        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2644                return 0;
2645
2646        /*
2647         * If ce matches the file in the work tree, we can reuse it.
2648         */
2649        if (ce_uptodate(ce) ||
2650            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2651                return 1;
2652
2653        return 0;
2654}
2655
2656static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2657{
2658        int len;
2659        char *data = xmalloc(100), *dirty = "";
2660
2661        /* Are we looking at the work tree? */
2662        if (s->dirty_submodule)
2663                dirty = "-dirty";
2664
2665        len = snprintf(data, 100,
2666                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2667        s->data = data;
2668        s->size = len;
2669        s->should_free = 1;
2670        if (size_only) {
2671                s->data = NULL;
2672                free(data);
2673        }
2674        return 0;
2675}
2676
2677/*
2678 * While doing rename detection and pickaxe operation, we may need to
2679 * grab the data for the blob (or file) for our own in-core comparison.
2680 * diff_filespec has data and size fields for this purpose.
2681 */
2682int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2683{
2684        int size_only = flags & CHECK_SIZE_ONLY;
2685        int err = 0;
2686        /*
2687         * demote FAIL to WARN to allow inspecting the situation
2688         * instead of refusing.
2689         */
2690        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2691                                    ? SAFE_CRLF_WARN
2692                                    : safe_crlf);
2693
2694        if (!DIFF_FILE_VALID(s))
2695                die("internal error: asking to populate invalid file.");
2696        if (S_ISDIR(s->mode))
2697                return -1;
2698
2699        if (s->data)
2700                return 0;
2701
2702        if (size_only && 0 < s->size)
2703                return 0;
2704
2705        if (S_ISGITLINK(s->mode))
2706                return diff_populate_gitlink(s, size_only);
2707
2708        if (!s->sha1_valid ||
2709            reuse_worktree_file(s->path, s->sha1, 0)) {
2710                struct strbuf buf = STRBUF_INIT;
2711                struct stat st;
2712                int fd;
2713
2714                if (lstat(s->path, &st) < 0) {
2715                        if (errno == ENOENT) {
2716                        err_empty:
2717                                err = -1;
2718                        empty:
2719                                s->data = (char *)"";
2720                                s->size = 0;
2721                                return err;
2722                        }
2723                }
2724                s->size = xsize_t(st.st_size);
2725                if (!s->size)
2726                        goto empty;
2727                if (S_ISLNK(st.st_mode)) {
2728                        struct strbuf sb = STRBUF_INIT;
2729
2730                        if (strbuf_readlink(&sb, s->path, s->size))
2731                                goto err_empty;
2732                        s->size = sb.len;
2733                        s->data = strbuf_detach(&sb, NULL);
2734                        s->should_free = 1;
2735                        return 0;
2736                }
2737                if (size_only)
2738                        return 0;
2739                if ((flags & CHECK_BINARY) &&
2740                    s->size > big_file_threshold && s->is_binary == -1) {
2741                        s->is_binary = 1;
2742                        return 0;
2743                }
2744                fd = open(s->path, O_RDONLY);
2745                if (fd < 0)
2746                        goto err_empty;
2747                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2748                close(fd);
2749                s->should_munmap = 1;
2750
2751                /*
2752                 * Convert from working tree format to canonical git format
2753                 */
2754                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2755                        size_t size = 0;
2756                        munmap(s->data, s->size);
2757                        s->should_munmap = 0;
2758                        s->data = strbuf_detach(&buf, &size);
2759                        s->size = size;
2760                        s->should_free = 1;
2761                }
2762        }
2763        else {
2764                enum object_type type;
2765                if (size_only || (flags & CHECK_BINARY)) {
2766                        type = sha1_object_info(s->sha1, &s->size);
2767                        if (type < 0)
2768                                die("unable to read %s", sha1_to_hex(s->sha1));
2769                        if (size_only)
2770                                return 0;
2771                        if (s->size > big_file_threshold && s->is_binary == -1) {
2772                                s->is_binary = 1;
2773                                return 0;
2774                        }
2775                }
2776                s->data = read_sha1_file(s->sha1, &type, &s->size);
2777                if (!s->data)
2778                        die("unable to read %s", sha1_to_hex(s->sha1));
2779                s->should_free = 1;
2780        }
2781        return 0;
2782}
2783
2784void diff_free_filespec_blob(struct diff_filespec *s)
2785{
2786        if (s->should_free)
2787                free(s->data);
2788        else if (s->should_munmap)
2789                munmap(s->data, s->size);
2790
2791        if (s->should_free || s->should_munmap) {
2792                s->should_free = s->should_munmap = 0;
2793                s->data = NULL;
2794        }
2795}
2796
2797void diff_free_filespec_data(struct diff_filespec *s)
2798{
2799        diff_free_filespec_blob(s);
2800        free(s->cnt_data);
2801        s->cnt_data = NULL;
2802}
2803
2804static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2805                           void *blob,
2806                           unsigned long size,
2807                           const unsigned char *sha1,
2808                           int mode)
2809{
2810        int fd;
2811        struct strbuf buf = STRBUF_INIT;
2812        struct strbuf template = STRBUF_INIT;
2813        char *path_dup = xstrdup(path);
2814        const char *base = basename(path_dup);
2815
2816        /* Generate "XXXXXX_basename.ext" */
2817        strbuf_addstr(&template, "XXXXXX_");
2818        strbuf_addstr(&template, base);
2819
2820        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2821                        strlen(base) + 1);
2822        if (fd < 0)
2823                die_errno("unable to create temp-file");
2824        if (convert_to_working_tree(path,
2825                        (const char *)blob, (size_t)size, &buf)) {
2826                blob = buf.buf;
2827                size = buf.len;
2828        }
2829        if (write_in_full(fd, blob, size) != size)
2830                die_errno("unable to write temp-file");
2831        close(fd);
2832        temp->name = temp->tmp_path;
2833        strcpy(temp->hex, sha1_to_hex(sha1));
2834        temp->hex[40] = 0;
2835        sprintf(temp->mode, "%06o", mode);
2836        strbuf_release(&buf);
2837        strbuf_release(&template);
2838        free(path_dup);
2839}
2840
2841static struct diff_tempfile *prepare_temp_file(const char *name,
2842                struct diff_filespec *one)
2843{
2844        struct diff_tempfile *temp = claim_diff_tempfile();
2845
2846        if (!DIFF_FILE_VALID(one)) {
2847        not_a_valid_file:
2848                /* A '-' entry produces this for file-2, and
2849                 * a '+' entry produces this for file-1.
2850                 */
2851                temp->name = "/dev/null";
2852                strcpy(temp->hex, ".");
2853                strcpy(temp->mode, ".");
2854                return temp;
2855        }
2856
2857        if (!remove_tempfile_installed) {
2858                atexit(remove_tempfile);
2859                sigchain_push_common(remove_tempfile_on_signal);
2860                remove_tempfile_installed = 1;
2861        }
2862
2863        if (!S_ISGITLINK(one->mode) &&
2864            (!one->sha1_valid ||
2865             reuse_worktree_file(name, one->sha1, 1))) {
2866                struct stat st;
2867                if (lstat(name, &st) < 0) {
2868                        if (errno == ENOENT)
2869                                goto not_a_valid_file;
2870                        die_errno("stat(%s)", name);
2871                }
2872                if (S_ISLNK(st.st_mode)) {
2873                        struct strbuf sb = STRBUF_INIT;
2874                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2875                                die_errno("readlink(%s)", name);
2876                        prep_temp_blob(name, temp, sb.buf, sb.len,
2877                                       (one->sha1_valid ?
2878                                        one->sha1 : null_sha1),
2879                                       (one->sha1_valid ?
2880                                        one->mode : S_IFLNK));
2881                        strbuf_release(&sb);
2882                }
2883                else {
2884                        /* we can borrow from the file in the work tree */
2885                        temp->name = name;
2886                        if (!one->sha1_valid)
2887                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2888                        else
2889                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2890                        /* Even though we may sometimes borrow the
2891                         * contents from the work tree, we always want
2892                         * one->mode.  mode is trustworthy even when
2893                         * !(one->sha1_valid), as long as
2894                         * DIFF_FILE_VALID(one).
2895                         */
2896                        sprintf(temp->mode, "%06o", one->mode);
2897                }
2898                return temp;
2899        }
2900        else {
2901                if (diff_populate_filespec(one, 0))
2902                        die("cannot read data blob for %s", one->path);
2903                prep_temp_blob(name, temp, one->data, one->size,
2904                               one->sha1, one->mode);
2905        }
2906        return temp;
2907}
2908
2909static void add_external_diff_name(struct argv_array *argv,
2910                                   const char *name,
2911                                   struct diff_filespec *df)
2912{
2913        struct diff_tempfile *temp = prepare_temp_file(name, df);
2914        argv_array_push(argv, temp->name);
2915        argv_array_push(argv, temp->hex);
2916        argv_array_push(argv, temp->mode);
2917}
2918
2919/* An external diff command takes:
2920 *
2921 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2922 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2923 *
2924 */
2925static void run_external_diff(const char *pgm,
2926                              const char *name,
2927                              const char *other,
2928                              struct diff_filespec *one,
2929                              struct diff_filespec *two,
2930                              const char *xfrm_msg,
2931                              int complete_rewrite,
2932                              struct diff_options *o)
2933{
2934        struct argv_array argv = ARGV_ARRAY_INIT;
2935        struct argv_array env = ARGV_ARRAY_INIT;
2936        struct diff_queue_struct *q = &diff_queued_diff;
2937
2938        argv_array_push(&argv, pgm);
2939        argv_array_push(&argv, name);
2940
2941        if (one && two) {
2942                add_external_diff_name(&argv, name, one);
2943                if (!other)
2944                        add_external_diff_name(&argv, name, two);
2945                else {
2946                        add_external_diff_name(&argv, other, two);
2947                        argv_array_push(&argv, other);
2948                        argv_array_push(&argv, xfrm_msg);
2949                }
2950        }
2951
2952        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2953        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2954
2955        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2956                die(_("external diff died, stopping at %s"), name);
2957
2958        remove_tempfile();
2959        argv_array_clear(&argv);
2960        argv_array_clear(&env);
2961}
2962
2963static int similarity_index(struct diff_filepair *p)
2964{
2965        return p->score * 100 / MAX_SCORE;
2966}
2967
2968static void fill_metainfo(struct strbuf *msg,
2969                          const char *name,
2970                          const char *other,
2971                          struct diff_filespec *one,
2972                          struct diff_filespec *two,
2973                          struct diff_options *o,
2974                          struct diff_filepair *p,
2975                          int *must_show_header,
2976                          int use_color)
2977{
2978        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2979        const char *reset = diff_get_color(use_color, DIFF_RESET);
2980        const char *line_prefix = diff_line_prefix(o);
2981
2982        *must_show_header = 1;
2983        strbuf_init(msg, PATH_MAX * 2 + 300);
2984        switch (p->status) {
2985        case DIFF_STATUS_COPIED:
2986                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2987                            line_prefix, set, similarity_index(p));
2988                strbuf_addf(msg, "%s\n%s%scopy from ",
2989                            reset,  line_prefix, set);
2990                quote_c_style(name, msg, NULL, 0);
2991                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2992                quote_c_style(other, msg, NULL, 0);
2993                strbuf_addf(msg, "%s\n", reset);
2994                break;
2995        case DIFF_STATUS_RENAMED:
2996                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2997                            line_prefix, set, similarity_index(p));
2998                strbuf_addf(msg, "%s\n%s%srename from ",
2999                            reset, line_prefix, set);
3000                quote_c_style(name, msg, NULL, 0);
3001                strbuf_addf(msg, "%s\n%s%srename to ",
3002                            reset, line_prefix, set);
3003                quote_c_style(other, msg, NULL, 0);
3004                strbuf_addf(msg, "%s\n", reset);
3005                break;
3006        case DIFF_STATUS_MODIFIED:
3007                if (p->score) {
3008                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3009                                    line_prefix,
3010                                    set, similarity_index(p), reset);
3011                        break;
3012                }
3013                /* fallthru */
3014        default:
3015                *must_show_header = 0;
3016        }
3017        if (one && two && hashcmp(one->sha1, two->sha1)) {
3018                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3019
3020                if (DIFF_OPT_TST(o, BINARY)) {
3021                        mmfile_t mf;
3022                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3023                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3024                                abbrev = 40;
3025                }
3026                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3027                            find_unique_abbrev(one->sha1, abbrev));
3028                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3029                if (one->mode == two->mode)
3030                        strbuf_addf(msg, " %06o", one->mode);
3031                strbuf_addf(msg, "%s\n", reset);
3032        }
3033}
3034
3035static void run_diff_cmd(const char *pgm,
3036                         const char *name,
3037                         const char *other,
3038                         const char *attr_path,
3039                         struct diff_filespec *one,
3040                         struct diff_filespec *two,
3041                         struct strbuf *msg,
3042                         struct diff_options *o,
3043                         struct diff_filepair *p)
3044{
3045        const char *xfrm_msg = NULL;
3046        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3047        int must_show_header = 0;
3048
3049
3050        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3051                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3052                if (drv && drv->external)
3053                        pgm = drv->external;
3054        }
3055
3056        if (msg) {
3057                /*
3058                 * don't use colors when the header is intended for an
3059                 * external diff driver
3060                 */
3061                fill_metainfo(msg, name, other, one, two, o, p,
3062                              &must_show_header,
3063                              want_color(o->use_color) && !pgm);
3064                xfrm_msg = msg->len ? msg->buf : NULL;
3065        }
3066
3067        if (pgm) {
3068                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3069                                  complete_rewrite, o);
3070                return;
3071        }
3072        if (one && two)
3073                builtin_diff(name, other ? other : name,
3074                             one, two, xfrm_msg, must_show_header,
3075                             o, complete_rewrite);
3076        else
3077                fprintf(o->file, "* Unmerged path %s\n", name);
3078}
3079
3080static void diff_fill_sha1_info(struct diff_filespec *one)
3081{
3082        if (DIFF_FILE_VALID(one)) {
3083                if (!one->sha1_valid) {
3084                        struct stat st;
3085                        if (one->is_stdin) {
3086                                hashcpy(one->sha1, null_sha1);
3087                                return;
3088                        }
3089                        if (lstat(one->path, &st) < 0)
3090                                die_errno("stat '%s'", one->path);
3091                        if (index_path(one->sha1, one->path, &st, 0))
3092                                die("cannot hash %s", one->path);
3093                }
3094        }
3095        else
3096                hashclr(one->sha1);
3097}
3098
3099static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3100{
3101        /* Strip the prefix but do not molest /dev/null and absolute paths */
3102        if (*namep && **namep != '/') {
3103                *namep += prefix_length;
3104                if (**namep == '/')
3105                        ++*namep;
3106        }
3107        if (*otherp && **otherp != '/') {
3108                *otherp += prefix_length;
3109                if (**otherp == '/')
3110                        ++*otherp;
3111        }
3112}
3113
3114static void run_diff(struct diff_filepair *p, struct diff_options *o)
3115{
3116        const char *pgm = external_diff();
3117        struct strbuf msg;
3118        struct diff_filespec *one = p->one;
3119        struct diff_filespec *two = p->two;
3120        const char *name;
3121        const char *other;
3122        const char *attr_path;
3123
3124        name  = p->one->path;
3125        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3126        attr_path = name;
3127        if (o->prefix_length)
3128                strip_prefix(o->prefix_length, &name, &other);
3129
3130        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3131                pgm = NULL;
3132
3133        if (DIFF_PAIR_UNMERGED(p)) {
3134                run_diff_cmd(pgm, name, NULL, attr_path,
3135                             NULL, NULL, NULL, o, p);
3136                return;
3137        }
3138
3139        diff_fill_sha1_info(one);
3140        diff_fill_sha1_info(two);
3141
3142        if (!pgm &&
3143            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3144            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3145                /*
3146                 * a filepair that changes between file and symlink
3147                 * needs to be split into deletion and creation.
3148                 */
3149                struct diff_filespec *null = alloc_filespec(two->path);
3150                run_diff_cmd(NULL, name, other, attr_path,
3151                             one, null, &msg, o, p);
3152                free(null);
3153                strbuf_release(&msg);
3154
3155                null = alloc_filespec(one->path);
3156                run_diff_cmd(NULL, name, other, attr_path,
3157                             null, two, &msg, o, p);
3158                free(null);
3159        }
3160        else
3161                run_diff_cmd(pgm, name, other, attr_path,
3162                             one, two, &msg, o, p);
3163
3164        strbuf_release(&msg);
3165}
3166
3167static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3168                         struct diffstat_t *diffstat)
3169{
3170        const char *name;
3171        const char *other;
3172
3173        if (DIFF_PAIR_UNMERGED(p)) {
3174                /* unmerged */
3175                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3176                return;
3177        }
3178
3179        name = p->one->path;
3180        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3181
3182        if (o->prefix_length)
3183                strip_prefix(o->prefix_length, &name, &other);
3184
3185        diff_fill_sha1_info(p->one);
3186        diff_fill_sha1_info(p->two);
3187
3188        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3189}
3190
3191static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3192{
3193        const char *name;
3194        const char *other;
3195        const char *attr_path;
3196
3197        if (DIFF_PAIR_UNMERGED(p)) {
3198                /* unmerged */
3199                return;
3200        }
3201
3202        name = p->one->path;
3203        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3204        attr_path = other ? other : name;
3205
3206        if (o->prefix_length)
3207                strip_prefix(o->prefix_length, &name, &other);
3208
3209        diff_fill_sha1_info(p->one);
3210        diff_fill_sha1_info(p->two);
3211
3212        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3213}
3214
3215void diff_setup(struct diff_options *options)
3216{
3217        memcpy(options, &default_diff_options, sizeof(*options));
3218
3219        options->file = stdout;
3220
3221        options->line_termination = '\n';
3222        options->break_opt = -1;
3223        options->rename_limit = -1;
3224        options->dirstat_permille = diff_dirstat_permille_default;
3225        options->context = diff_context_default;
3226        DIFF_OPT_SET(options, RENAME_EMPTY);
3227
3228        /* pathchange left =NULL by default */
3229        options->change = diff_change;
3230        options->add_remove = diff_addremove;
3231        options->use_color = diff_use_color_default;
3232        options->detect_rename = diff_detect_rename_default;
3233        options->xdl_opts |= diff_algorithm;
3234
3235        options->orderfile = diff_order_file_cfg;
3236
3237        if (diff_no_prefix) {
3238                options->a_prefix = options->b_prefix = "";
3239        } else if (!diff_mnemonic_prefix) {
3240                options->a_prefix = "a/";
3241                options->b_prefix = "b/";
3242        }
3243}
3244
3245void diff_setup_done(struct diff_options *options)
3246{
3247        int count = 0;
3248
3249        if (options->set_default)
3250                options->set_default(options);
3251
3252        if (options->output_format & DIFF_FORMAT_NAME)
3253                count++;
3254        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3255                count++;
3256        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3257                count++;
3258        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3259                count++;
3260        if (count > 1)
3261                die("--name-only, --name-status, --check and -s are mutually exclusive");
3262
3263        /*
3264         * Most of the time we can say "there are changes"
3265         * only by checking if there are changed paths, but
3266         * --ignore-whitespace* options force us to look
3267         * inside contents.
3268         */
3269
3270        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3271            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3272            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3273                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3274        else
3275                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3276
3277        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3278                options->detect_rename = DIFF_DETECT_COPY;
3279
3280        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3281                options->prefix = NULL;
3282        if (options->prefix)
3283                options->prefix_length = strlen(options->prefix);
3284        else
3285                options->prefix_length = 0;
3286
3287        if (options->output_format & (DIFF_FORMAT_NAME |
3288                                      DIFF_FORMAT_NAME_STATUS |
3289                                      DIFF_FORMAT_CHECKDIFF |
3290                                      DIFF_FORMAT_NO_OUTPUT))
3291                options->output_format &= ~(DIFF_FORMAT_RAW |
3292                                            DIFF_FORMAT_NUMSTAT |
3293                                            DIFF_FORMAT_DIFFSTAT |
3294                                            DIFF_FORMAT_SHORTSTAT |
3295                                            DIFF_FORMAT_DIRSTAT |
3296                                            DIFF_FORMAT_SUMMARY |
3297                                            DIFF_FORMAT_PATCH);
3298
3299        /*
3300         * These cases always need recursive; we do not drop caller-supplied
3301         * recursive bits for other formats here.
3302         */
3303        if (options->output_format & (DIFF_FORMAT_PATCH |
3304                                      DIFF_FORMAT_NUMSTAT |
3305                                      DIFF_FORMAT_DIFFSTAT |
3306                                      DIFF_FORMAT_SHORTSTAT |
3307                                      DIFF_FORMAT_DIRSTAT |
3308                                      DIFF_FORMAT_SUMMARY |
3309                                      DIFF_FORMAT_CHECKDIFF))
3310                DIFF_OPT_SET(options, RECURSIVE);
3311        /*
3312         * Also pickaxe would not work very well if you do not say recursive
3313         */
3314        if (options->pickaxe)
3315                DIFF_OPT_SET(options, RECURSIVE);
3316        /*
3317         * When patches are generated, submodules diffed against the work tree
3318         * must be checked for dirtiness too so it can be shown in the output
3319         */
3320        if (options->output_format & DIFF_FORMAT_PATCH)
3321                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3322
3323        if (options->detect_rename && options->rename_limit < 0)
3324                options->rename_limit = diff_rename_limit_default;
3325        if (options->setup & DIFF_SETUP_USE_CACHE) {
3326                if (!active_cache)
3327                        /* read-cache does not die even when it fails
3328                         * so it is safe for us to do this here.  Also
3329                         * it does not smudge active_cache or active_nr
3330                         * when it fails, so we do not have to worry about
3331                         * cleaning it up ourselves either.
3332                         */
3333                        read_cache();
3334        }
3335        if (options->abbrev <= 0 || 40 < options->abbrev)
3336                options->abbrev = 40; /* full */
3337
3338        /*
3339         * It does not make sense to show the first hit we happened
3340         * to have found.  It does not make sense not to return with
3341         * exit code in such a case either.
3342         */
3343        if (DIFF_OPT_TST(options, QUICK)) {
3344                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3345                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3346        }
3347
3348        options->diff_path_counter = 0;
3349
3350        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3351                die(_("--follow requires exactly one pathspec"));
3352}
3353
3354static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3355{
3356        char c, *eq;
3357        int len;
3358
3359        if (*arg != '-')
3360                return 0;
3361        c = *++arg;
3362        if (!c)
3363                return 0;
3364        if (c == arg_short) {
3365                c = *++arg;
3366                if (!c)
3367                        return 1;
3368                if (val && isdigit(c)) {
3369                        char *end;
3370                        int n = strtoul(arg, &end, 10);
3371                        if (*end)
3372                                return 0;
3373                        *val = n;
3374                        return 1;
3375                }
3376                return 0;
3377        }
3378        if (c != '-')
3379                return 0;
3380        arg++;
3381        eq = strchrnul(arg, '=');
3382        len = eq - arg;
3383        if (!len || strncmp(arg, arg_long, len))
3384                return 0;
3385        if (*eq) {
3386                int n;
3387                char *end;
3388                if (!isdigit(*++eq))
3389                        return 0;
3390                n = strtoul(eq, &end, 10);
3391                if (*end)
3392                        return 0;
3393                *val = n;
3394        }
3395        return 1;
3396}
3397
3398static int diff_scoreopt_parse(const char *opt);
3399
3400static inline int short_opt(char opt, const char **argv,
3401                            const char **optarg)
3402{
3403        const char *arg = argv[0];
3404        if (arg[0] != '-' || arg[1] != opt)
3405                return 0;
3406        if (arg[2] != '\0') {
3407                *optarg = arg + 2;
3408                return 1;
3409        }
3410        if (!argv[1])
3411                die("Option '%c' requires a value", opt);
3412        *optarg = argv[1];
3413        return 2;
3414}
3415
3416int parse_long_opt(const char *opt, const char **argv,
3417                   const char **optarg)
3418{
3419        const char *arg = argv[0];
3420        if (!skip_prefix(arg, "--", &arg))
3421                return 0;
3422        if (!skip_prefix(arg, opt, &arg))
3423                return 0;
3424        if (*arg == '=') { /* stuck form: --option=value */
3425                *optarg = arg + 1;
3426                return 1;
3427        }
3428        if (*arg != '\0')
3429                return 0;
3430        /* separate form: --option value */
3431        if (!argv[1])
3432                die("Option '--%s' requires a value", opt);
3433        *optarg = argv[1];
3434        return 2;
3435}
3436
3437static int stat_opt(struct diff_options *options, const char **av)
3438{
3439        const char *arg = av[0];
3440        char *end;
3441        int width = options->stat_width;
3442        int name_width = options->stat_name_width;
3443        int graph_width = options->stat_graph_width;
3444        int count = options->stat_count;
3445        int argcount = 1;
3446
3447        if (!skip_prefix(arg, "--stat", &arg))
3448                die("BUG: stat option does not begin with --stat: %s", arg);
3449        end = (char *)arg;
3450
3451        switch (*arg) {
3452        case '-':
3453                if (skip_prefix(arg, "-width", &arg)) {
3454                        if (*arg == '=')
3455                                width = strtoul(arg + 1, &end, 10);
3456                        else if (!*arg && !av[1])
3457                                die("Option '--stat-width' requires a value");
3458                        else if (!*arg) {
3459                                width = strtoul(av[1], &end, 10);
3460                                argcount = 2;
3461                        }
3462                } else if (skip_prefix(arg, "-name-width", &arg)) {
3463                        if (*arg == '=')
3464                                name_width = strtoul(arg + 1, &end, 10);
3465                        else if (!*arg && !av[1])
3466                                die("Option '--stat-name-width' requires a value");
3467                        else if (!*arg) {
3468                                name_width = strtoul(av[1], &end, 10);
3469                                argcount = 2;
3470                        }
3471                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3472                        if (*arg == '=')
3473                                graph_width = strtoul(arg + 1, &end, 10);
3474                        else if (!*arg && !av[1])
3475                                die("Option '--stat-graph-width' requires a value");
3476                        else if (!*arg) {
3477                                graph_width = strtoul(av[1], &end, 10);
3478                                argcount = 2;
3479                        }
3480                } else if (skip_prefix(arg, "-count", &arg)) {
3481                        if (*arg == '=')
3482                                count = strtoul(arg + 1, &end, 10);
3483                        else if (!*arg && !av[1])
3484                                die("Option '--stat-count' requires a value");
3485                        else if (!*arg) {
3486                                count = strtoul(av[1], &end, 10);
3487                                argcount = 2;
3488                        }
3489                }
3490                break;
3491        case '=':
3492                width = strtoul(arg+1, &end, 10);
3493                if (*end == ',')
3494                        name_width = strtoul(end+1, &end, 10);
3495                if (*end == ',')
3496                        count = strtoul(end+1, &end, 10);
3497        }
3498
3499        /* Important! This checks all the error cases! */
3500        if (*end)
3501                return 0;
3502        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3503        options->stat_name_width = name_width;
3504        options->stat_graph_width = graph_width;
3505        options->stat_width = width;
3506        options->stat_count = count;
3507        return argcount;
3508}
3509
3510static int parse_dirstat_opt(struct diff_options *options, const char *params)
3511{
3512        struct strbuf errmsg = STRBUF_INIT;
3513        if (parse_dirstat_params(options, params, &errmsg))
3514                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3515                    errmsg.buf);
3516        strbuf_release(&errmsg);
3517        /*
3518         * The caller knows a dirstat-related option is given from the command
3519         * line; allow it to say "return this_function();"
3520         */
3521        options->output_format |= DIFF_FORMAT_DIRSTAT;
3522        return 1;
3523}
3524
3525static int parse_submodule_opt(struct diff_options *options, const char *value)
3526{
3527        if (parse_submodule_params(options, value))
3528                die(_("Failed to parse --submodule option parameter: '%s'"),
3529                        value);
3530        return 1;
3531}
3532
3533static const char diff_status_letters[] = {
3534        DIFF_STATUS_ADDED,
3535        DIFF_STATUS_COPIED,
3536        DIFF_STATUS_DELETED,
3537        DIFF_STATUS_MODIFIED,
3538        DIFF_STATUS_RENAMED,
3539        DIFF_STATUS_TYPE_CHANGED,
3540        DIFF_STATUS_UNKNOWN,
3541        DIFF_STATUS_UNMERGED,
3542        DIFF_STATUS_FILTER_AON,
3543        DIFF_STATUS_FILTER_BROKEN,
3544        '\0',
3545};
3546
3547static unsigned int filter_bit['Z' + 1];
3548
3549static void prepare_filter_bits(void)
3550{
3551        int i;
3552
3553        if (!filter_bit[DIFF_STATUS_ADDED]) {
3554                for (i = 0; diff_status_letters[i]; i++)
3555                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3556        }
3557}
3558
3559static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3560{
3561        return opt->filter & filter_bit[(int) status];
3562}
3563
3564static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3565{
3566        int i, optch;
3567
3568        prepare_filter_bits();
3569
3570        /*
3571         * If there is a negation e.g. 'd' in the input, and we haven't
3572         * initialized the filter field with another --diff-filter, start
3573         * from full set of bits, except for AON.
3574         */
3575        if (!opt->filter) {
3576                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3577                        if (optch < 'a' || 'z' < optch)
3578                                continue;
3579                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3580                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3581                        break;
3582                }
3583        }
3584
3585        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3586                unsigned int bit;
3587                int negate;
3588
3589                if ('a' <= optch && optch <= 'z') {
3590                        negate = 1;
3591                        optch = toupper(optch);
3592                } else {
3593                        negate = 0;
3594                }
3595
3596                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3597                if (!bit)
3598                        return optarg[i];
3599                if (negate)
3600                        opt->filter &= ~bit;
3601                else
3602                        opt->filter |= bit;
3603        }
3604        return 0;
3605}
3606
3607static void enable_patch_output(int *fmt) {
3608        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3609        *fmt |= DIFF_FORMAT_PATCH;
3610}
3611
3612int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3613{
3614        const char *arg = av[0];
3615        const char *optarg;
3616        int argcount;
3617
3618        /* Output format options */
3619        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3620            || opt_arg(arg, 'U', "unified", &options->context))
3621                enable_patch_output(&options->output_format);
3622        else if (!strcmp(arg, "--raw"))
3623                options->output_format |= DIFF_FORMAT_RAW;
3624        else if (!strcmp(arg, "--patch-with-raw")) {
3625                enable_patch_output(&options->output_format);
3626                options->output_format |= DIFF_FORMAT_RAW;
3627        } else if (!strcmp(arg, "--numstat"))
3628                options->output_format |= DIFF_FORMAT_NUMSTAT;
3629        else if (!strcmp(arg, "--shortstat"))
3630                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3631        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3632                return parse_dirstat_opt(options, "");
3633        else if (skip_prefix(arg, "-X", &arg))
3634                return parse_dirstat_opt(options, arg);
3635        else if (skip_prefix(arg, "--dirstat=", &arg))
3636                return parse_dirstat_opt(options, arg);
3637        else if (!strcmp(arg, "--cumulative"))
3638                return parse_dirstat_opt(options, "cumulative");
3639        else if (!strcmp(arg, "--dirstat-by-file"))
3640                return parse_dirstat_opt(options, "files");
3641        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3642                parse_dirstat_opt(options, "files");
3643                return parse_dirstat_opt(options, arg);
3644        }
3645        else if (!strcmp(arg, "--check"))
3646                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3647        else if (!strcmp(arg, "--summary"))
3648                options->output_format |= DIFF_FORMAT_SUMMARY;
3649        else if (!strcmp(arg, "--patch-with-stat")) {
3650                enable_patch_output(&options->output_format);
3651                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3652        } else if (!strcmp(arg, "--name-only"))
3653                options->output_format |= DIFF_FORMAT_NAME;
3654        else if (!strcmp(arg, "--name-status"))
3655                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3656        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3657                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3658        else if (starts_with(arg, "--stat"))
3659                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3660                return stat_opt(options, av);
3661
3662        /* renames options */
3663        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3664                 !strcmp(arg, "--break-rewrites")) {
3665                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3666                        return error("invalid argument to -B: %s", arg+2);
3667        }
3668        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3669                 !strcmp(arg, "--find-renames")) {
3670                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3671                        return error("invalid argument to -M: %s", arg+2);
3672                options->detect_rename = DIFF_DETECT_RENAME;
3673        }
3674        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3675                options->irreversible_delete = 1;
3676        }
3677        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3678                 !strcmp(arg, "--find-copies")) {
3679                if (options->detect_rename == DIFF_DETECT_COPY)
3680                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3681                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3682                        return error("invalid argument to -C: %s", arg+2);
3683                options->detect_rename = DIFF_DETECT_COPY;
3684        }
3685        else if (!strcmp(arg, "--no-renames"))
3686                options->detect_rename = 0;
3687        else if (!strcmp(arg, "--rename-empty"))
3688                DIFF_OPT_SET(options, RENAME_EMPTY);
3689        else if (!strcmp(arg, "--no-rename-empty"))
3690                DIFF_OPT_CLR(options, RENAME_EMPTY);
3691        else if (!strcmp(arg, "--relative"))
3692                DIFF_OPT_SET(options, RELATIVE_NAME);
3693        else if (skip_prefix(arg, "--relative=", &arg)) {
3694                DIFF_OPT_SET(options, RELATIVE_NAME);
3695                options->prefix = arg;
3696        }
3697
3698        /* xdiff options */
3699        else if (!strcmp(arg, "--minimal"))
3700                DIFF_XDL_SET(options, NEED_MINIMAL);
3701        else if (!strcmp(arg, "--no-minimal"))
3702                DIFF_XDL_CLR(options, NEED_MINIMAL);
3703        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3704                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3705        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3706                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3707        else if (!strcmp(arg, "--ignore-space-at-eol"))
3708                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3709        else if (!strcmp(arg, "--ignore-blank-lines"))
3710                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3711        else if (!strcmp(arg, "--patience"))
3712                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3713        else if (!strcmp(arg, "--histogram"))
3714                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3715        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3716                long value = parse_algorithm_value(optarg);
3717                if (value < 0)
3718                        return error("option diff-algorithm accepts \"myers\", "
3719                                     "\"minimal\", \"patience\" and \"histogram\"");
3720                /* clear out previous settings */
3721                DIFF_XDL_CLR(options, NEED_MINIMAL);
3722                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3723                options->xdl_opts |= value;
3724                return argcount;
3725        }
3726
3727        /* flags options */
3728        else if (!strcmp(arg, "--binary")) {
3729                enable_patch_output(&options->output_format);
3730                DIFF_OPT_SET(options, BINARY);
3731        }
3732        else if (!strcmp(arg, "--full-index"))
3733                DIFF_OPT_SET(options, FULL_INDEX);
3734        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3735                DIFF_OPT_SET(options, TEXT);
3736        else if (!strcmp(arg, "-R"))
3737                DIFF_OPT_SET(options, REVERSE_DIFF);
3738        else if (!strcmp(arg, "--find-copies-harder"))
3739                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3740        else if (!strcmp(arg, "--follow"))
3741                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3742        else if (!strcmp(arg, "--no-follow"))
3743                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3744        else if (!strcmp(arg, "--color"))
3745                options->use_color = 1;
3746        else if (skip_prefix(arg, "--color=", &arg)) {
3747                int value = git_config_colorbool(NULL, arg);
3748                if (value < 0)
3749                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3750                options->use_color = value;
3751        }
3752        else if (!strcmp(arg, "--no-color"))
3753                options->use_color = 0;
3754        else if (!strcmp(arg, "--color-words")) {
3755                options->use_color = 1;
3756                options->word_diff = DIFF_WORDS_COLOR;
3757        }
3758        else if (skip_prefix(arg, "--color-words=", &arg)) {
3759                options->use_color = 1;
3760                options->word_diff = DIFF_WORDS_COLOR;
3761                options->word_regex = arg;
3762        }
3763        else if (!strcmp(arg, "--word-diff")) {
3764                if (options->word_diff == DIFF_WORDS_NONE)
3765                        options->word_diff = DIFF_WORDS_PLAIN;
3766        }
3767        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3768                if (!strcmp(arg, "plain"))
3769                        options->word_diff = DIFF_WORDS_PLAIN;
3770                else if (!strcmp(arg, "color")) {
3771                        options->use_color = 1;
3772                        options->word_diff = DIFF_WORDS_COLOR;
3773                }
3774                else if (!strcmp(arg, "porcelain"))
3775                        options->word_diff = DIFF_WORDS_PORCELAIN;
3776                else if (!strcmp(arg, "none"))
3777                        options->word_diff = DIFF_WORDS_NONE;
3778                else
3779                        die("bad --word-diff argument: %s", arg);
3780        }
3781        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3782                if (options->word_diff == DIFF_WORDS_NONE)
3783                        options->word_diff = DIFF_WORDS_PLAIN;
3784                options->word_regex = optarg;
3785                return argcount;
3786        }
3787        else if (!strcmp(arg, "--exit-code"))
3788                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3789        else if (!strcmp(arg, "--quiet"))
3790                DIFF_OPT_SET(options, QUICK);
3791        else if (!strcmp(arg, "--ext-diff"))
3792                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3793        else if (!strcmp(arg, "--no-ext-diff"))
3794                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3795        else if (!strcmp(arg, "--textconv"))
3796                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3797        else if (!strcmp(arg, "--no-textconv"))
3798                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3799        else if (!strcmp(arg, "--ignore-submodules")) {
3800                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3801                handle_ignore_submodules_arg(options, "all");
3802        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3803                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3804                handle_ignore_submodules_arg(options, arg);
3805        } else if (!strcmp(arg, "--submodule"))
3806                DIFF_OPT_SET(options, SUBMODULE_LOG);
3807        else if (skip_prefix(arg, "--submodule=", &arg))
3808                return parse_submodule_opt(options, arg);
3809
3810        /* misc options */
3811        else if (!strcmp(arg, "-z"))
3812                options->line_termination = 0;
3813        else if ((argcount = short_opt('l', av, &optarg))) {
3814                options->rename_limit = strtoul(optarg, NULL, 10);
3815                return argcount;
3816        }
3817        else if ((argcount = short_opt('S', av, &optarg))) {
3818                options->pickaxe = optarg;
3819                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3820                return argcount;
3821        } else if ((argcount = short_opt('G', av, &optarg))) {
3822                options->pickaxe = optarg;
3823                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3824                return argcount;
3825        }
3826        else if (!strcmp(arg, "--pickaxe-all"))
3827                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3828        else if (!strcmp(arg, "--pickaxe-regex"))
3829                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3830        else if ((argcount = short_opt('O', av, &optarg))) {
3831                options->orderfile = optarg;
3832                return argcount;
3833        }
3834        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3835                int offending = parse_diff_filter_opt(optarg, options);
3836                if (offending)
3837                        die("unknown change class '%c' in --diff-filter=%s",
3838                            offending, optarg);
3839                return argcount;
3840        }
3841        else if (!strcmp(arg, "--abbrev"))
3842                options->abbrev = DEFAULT_ABBREV;
3843        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3844                options->abbrev = strtoul(arg, NULL, 10);
3845                if (options->abbrev < MINIMUM_ABBREV)
3846                        options->abbrev = MINIMUM_ABBREV;
3847                else if (40 < options->abbrev)
3848                        options->abbrev = 40;
3849        }
3850        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3851                options->a_prefix = optarg;
3852                return argcount;
3853        }
3854        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3855                options->b_prefix = optarg;
3856                return argcount;
3857        }
3858        else if (!strcmp(arg, "--no-prefix"))
3859                options->a_prefix = options->b_prefix = "";
3860        else if (opt_arg(arg, '\0', "inter-hunk-context",
3861                         &options->interhunkcontext))
3862                ;
3863        else if (!strcmp(arg, "-W"))
3864                DIFF_OPT_SET(options, FUNCCONTEXT);
3865        else if (!strcmp(arg, "--function-context"))
3866                DIFF_OPT_SET(options, FUNCCONTEXT);
3867        else if (!strcmp(arg, "--no-function-context"))
3868                DIFF_OPT_CLR(options, FUNCCONTEXT);
3869        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3870                options->file = fopen(optarg, "w");
3871                if (!options->file)
3872                        die_errno("Could not open '%s'", optarg);
3873                options->close_file = 1;
3874                return argcount;
3875        } else
3876                return 0;
3877        return 1;
3878}
3879
3880int parse_rename_score(const char **cp_p)
3881{
3882        unsigned long num, scale;
3883        int ch, dot;
3884        const char *cp = *cp_p;
3885
3886        num = 0;
3887        scale = 1;
3888        dot = 0;
3889        for (;;) {
3890                ch = *cp;
3891                if ( !dot && ch == '.' ) {
3892                        scale = 1;
3893                        dot = 1;
3894                } else if ( ch == '%' ) {
3895                        scale = dot ? scale*100 : 100;
3896                        cp++;   /* % is always at the end */
3897                        break;
3898                } else if ( ch >= '0' && ch <= '9' ) {
3899                        if ( scale < 100000 ) {
3900                                scale *= 10;
3901                                num = (num*10) + (ch-'0');
3902                        }
3903                } else {
3904                        break;
3905                }
3906                cp++;
3907        }
3908        *cp_p = cp;
3909
3910        /* user says num divided by scale and we say internally that
3911         * is MAX_SCORE * num / scale.
3912         */
3913        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3914}
3915
3916static int diff_scoreopt_parse(const char *opt)
3917{
3918        int opt1, opt2, cmd;
3919
3920        if (*opt++ != '-')
3921                return -1;
3922        cmd = *opt++;
3923        if (cmd == '-') {
3924                /* convert the long-form arguments into short-form versions */
3925                if (skip_prefix(opt, "break-rewrites", &opt)) {
3926                        if (*opt == 0 || *opt++ == '=')
3927                                cmd = 'B';
3928                } else if (skip_prefix(opt, "find-copies", &opt)) {
3929                        if (*opt == 0 || *opt++ == '=')
3930                                cmd = 'C';
3931                } else if (skip_prefix(opt, "find-renames", &opt)) {
3932                        if (*opt == 0 || *opt++ == '=')
3933                                cmd = 'M';
3934                }
3935        }
3936        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3937                return -1; /* that is not a -M, -C, or -B option */
3938
3939        opt1 = parse_rename_score(&opt);
3940        if (cmd != 'B')
3941                opt2 = 0;
3942        else {
3943                if (*opt == 0)
3944                        opt2 = 0;
3945                else if (*opt != '/')
3946                        return -1; /* we expect -B80/99 or -B80 */
3947                else {
3948                        opt++;
3949                        opt2 = parse_rename_score(&opt);
3950                }
3951        }
3952        if (*opt != 0)
3953                return -1;
3954        return opt1 | (opt2 << 16);
3955}
3956
3957struct diff_queue_struct diff_queued_diff;
3958
3959void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3960{
3961        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
3962        queue->queue[queue->nr++] = dp;
3963}
3964
3965struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3966                                 struct diff_filespec *one,
3967                                 struct diff_filespec *two)
3968{
3969        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3970        dp->one = one;
3971        dp->two = two;
3972        if (queue)
3973                diff_q(queue, dp);
3974        return dp;
3975}
3976
3977void diff_free_filepair(struct diff_filepair *p)
3978{
3979        free_filespec(p->one);
3980        free_filespec(p->two);
3981        free(p);
3982}
3983
3984/* This is different from find_unique_abbrev() in that
3985 * it stuffs the result with dots for alignment.
3986 */
3987const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3988{
3989        int abblen;
3990        const char *abbrev;
3991        if (len == 40)
3992                return sha1_to_hex(sha1);
3993
3994        abbrev = find_unique_abbrev(sha1, len);
3995        abblen = strlen(abbrev);
3996        if (abblen < 37) {
3997                static char hex[41];
3998                if (len < abblen && abblen <= len + 2)
3999                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
4000                else
4001                        sprintf(hex, "%s...", abbrev);
4002                return hex;
4003        }
4004        return sha1_to_hex(sha1);
4005}
4006
4007static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4008{
4009        int line_termination = opt->line_termination;
4010        int inter_name_termination = line_termination ? '\t' : '\0';
4011
4012        fprintf(opt->file, "%s", diff_line_prefix(opt));
4013        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4014                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4015                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4016                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4017        }
4018        if (p->score) {
4019                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4020                        inter_name_termination);
4021        } else {
4022                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4023        }
4024
4025        if (p->status == DIFF_STATUS_COPIED ||
4026            p->status == DIFF_STATUS_RENAMED) {
4027                const char *name_a, *name_b;
4028                name_a = p->one->path;
4029                name_b = p->two->path;
4030                strip_prefix(opt->prefix_length, &name_a, &name_b);
4031                write_name_quoted(name_a, opt->file, inter_name_termination);
4032                write_name_quoted(name_b, opt->file, line_termination);
4033        } else {
4034                const char *name_a, *name_b;
4035                name_a = p->one->mode ? p->one->path : p->two->path;
4036                name_b = NULL;
4037                strip_prefix(opt->prefix_length, &name_a, &name_b);
4038                write_name_quoted(name_a, opt->file, line_termination);
4039        }
4040}
4041
4042int diff_unmodified_pair(struct diff_filepair *p)
4043{
4044        /* This function is written stricter than necessary to support
4045         * the currently implemented transformers, but the idea is to
4046         * let transformers to produce diff_filepairs any way they want,
4047         * and filter and clean them up here before producing the output.
4048         */
4049        struct diff_filespec *one = p->one, *two = p->two;
4050
4051        if (DIFF_PAIR_UNMERGED(p))
4052                return 0; /* unmerged is interesting */
4053
4054        /* deletion, addition, mode or type change
4055         * and rename are all interesting.
4056         */
4057        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4058            DIFF_PAIR_MODE_CHANGED(p) ||
4059            strcmp(one->path, two->path))
4060                return 0;
4061
4062        /* both are valid and point at the same path.  that is, we are
4063         * dealing with a change.
4064         */
4065        if (one->sha1_valid && two->sha1_valid &&
4066            !hashcmp(one->sha1, two->sha1) &&
4067            !one->dirty_submodule && !two->dirty_submodule)
4068                return 1; /* no change */
4069        if (!one->sha1_valid && !two->sha1_valid)
4070                return 1; /* both look at the same file on the filesystem. */
4071        return 0;
4072}
4073
4074static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4075{
4076        if (diff_unmodified_pair(p))
4077                return;
4078
4079        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4080            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4081                return; /* no tree diffs in patch format */
4082
4083        run_diff(p, o);
4084}
4085
4086static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4087                            struct diffstat_t *diffstat)
4088{
4089        if (diff_unmodified_pair(p))
4090                return;
4091
4092        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4093            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4094                return; /* no useful stat for tree diffs */
4095
4096        run_diffstat(p, o, diffstat);
4097}
4098
4099static void diff_flush_checkdiff(struct diff_filepair *p,
4100                struct diff_options *o)
4101{
4102        if (diff_unmodified_pair(p))
4103                return;
4104
4105        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4106            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4107                return; /* nothing to check in tree diffs */
4108
4109        run_checkdiff(p, o);
4110}
4111
4112int diff_queue_is_empty(void)
4113{
4114        struct diff_queue_struct *q = &diff_queued_diff;
4115        int i;
4116        for (i = 0; i < q->nr; i++)
4117                if (!diff_unmodified_pair(q->queue[i]))
4118                        return 0;
4119        return 1;
4120}
4121
4122#if DIFF_DEBUG
4123void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4124{
4125        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4126                x, one ? one : "",
4127                s->path,
4128                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4129                s->mode,
4130                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4131        fprintf(stderr, "queue[%d] %s size %lu\n",
4132                x, one ? one : "",
4133                s->size);
4134}
4135
4136void diff_debug_filepair(const struct diff_filepair *p, int i)
4137{
4138        diff_debug_filespec(p->one, i, "one");
4139        diff_debug_filespec(p->two, i, "two");
4140        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4141                p->score, p->status ? p->status : '?',
4142                p->one->rename_used, p->broken_pair);
4143}
4144
4145void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4146{
4147        int i;
4148        if (msg)
4149                fprintf(stderr, "%s\n", msg);
4150        fprintf(stderr, "q->nr = %d\n", q->nr);
4151        for (i = 0; i < q->nr; i++) {
4152                struct diff_filepair *p = q->queue[i];
4153                diff_debug_filepair(p, i);
4154        }
4155}
4156#endif
4157
4158static void diff_resolve_rename_copy(void)
4159{
4160        int i;
4161        struct diff_filepair *p;
4162        struct diff_queue_struct *q = &diff_queued_diff;
4163
4164        diff_debug_queue("resolve-rename-copy", q);
4165
4166        for (i = 0; i < q->nr; i++) {
4167                p = q->queue[i];
4168                p->status = 0; /* undecided */
4169                if (DIFF_PAIR_UNMERGED(p))
4170                        p->status = DIFF_STATUS_UNMERGED;
4171                else if (!DIFF_FILE_VALID(p->one))
4172                        p->status = DIFF_STATUS_ADDED;
4173                else if (!DIFF_FILE_VALID(p->two))
4174                        p->status = DIFF_STATUS_DELETED;
4175                else if (DIFF_PAIR_TYPE_CHANGED(p))
4176                        p->status = DIFF_STATUS_TYPE_CHANGED;
4177
4178                /* from this point on, we are dealing with a pair
4179                 * whose both sides are valid and of the same type, i.e.
4180                 * either in-place edit or rename/copy edit.
4181                 */
4182                else if (DIFF_PAIR_RENAME(p)) {
4183                        /*
4184                         * A rename might have re-connected a broken
4185                         * pair up, causing the pathnames to be the
4186                         * same again. If so, that's not a rename at
4187                         * all, just a modification..
4188                         *
4189                         * Otherwise, see if this source was used for
4190                         * multiple renames, in which case we decrement
4191                         * the count, and call it a copy.
4192                         */
4193                        if (!strcmp(p->one->path, p->two->path))
4194                                p->status = DIFF_STATUS_MODIFIED;
4195                        else if (--p->one->rename_used > 0)
4196                                p->status = DIFF_STATUS_COPIED;
4197                        else
4198                                p->status = DIFF_STATUS_RENAMED;
4199                }
4200                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4201                         p->one->mode != p->two->mode ||
4202                         p->one->dirty_submodule ||
4203                         p->two->dirty_submodule ||
4204                         is_null_sha1(p->one->sha1))
4205                        p->status = DIFF_STATUS_MODIFIED;
4206                else {
4207                        /* This is a "no-change" entry and should not
4208                         * happen anymore, but prepare for broken callers.
4209                         */
4210                        error("feeding unmodified %s to diffcore",
4211                              p->one->path);
4212                        p->status = DIFF_STATUS_UNKNOWN;
4213                }
4214        }
4215        diff_debug_queue("resolve-rename-copy done", q);
4216}
4217
4218static int check_pair_status(struct diff_filepair *p)
4219{
4220        switch (p->status) {
4221        case DIFF_STATUS_UNKNOWN:
4222                return 0;
4223        case 0:
4224                die("internal error in diff-resolve-rename-copy");
4225        default:
4226                return 1;
4227        }
4228}
4229
4230static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4231{
4232        int fmt = opt->output_format;
4233
4234        if (fmt & DIFF_FORMAT_CHECKDIFF)
4235                diff_flush_checkdiff(p, opt);
4236        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4237                diff_flush_raw(p, opt);
4238        else if (fmt & DIFF_FORMAT_NAME) {
4239                const char *name_a, *name_b;
4240                name_a = p->two->path;
4241                name_b = NULL;
4242                strip_prefix(opt->prefix_length, &name_a, &name_b);
4243                write_name_quoted(name_a, opt->file, opt->line_termination);
4244        }
4245}
4246
4247static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4248{
4249        if (fs->mode)
4250                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4251        else
4252                fprintf(file, " %s ", newdelete);
4253        write_name_quoted(fs->path, file, '\n');
4254}
4255
4256
4257static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4258                const char *line_prefix)
4259{
4260        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4261                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4262                        p->two->mode, show_name ? ' ' : '\n');
4263                if (show_name) {
4264                        write_name_quoted(p->two->path, file, '\n');
4265                }
4266        }
4267}
4268
4269static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4270                        const char *line_prefix)
4271{
4272        char *names = pprint_rename(p->one->path, p->two->path);
4273
4274        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4275        free(names);
4276        show_mode_change(file, p, 0, line_prefix);
4277}
4278
4279static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4280{
4281        FILE *file = opt->file;
4282        const char *line_prefix = diff_line_prefix(opt);
4283
4284        switch(p->status) {
4285        case DIFF_STATUS_DELETED:
4286                fputs(line_prefix, file);
4287                show_file_mode_name(file, "delete", p->one);
4288                break;
4289        case DIFF_STATUS_ADDED:
4290                fputs(line_prefix, file);
4291                show_file_mode_name(file, "create", p->two);
4292                break;
4293        case DIFF_STATUS_COPIED:
4294                fputs(line_prefix, file);
4295                show_rename_copy(file, "copy", p, line_prefix);
4296                break;
4297        case DIFF_STATUS_RENAMED:
4298                fputs(line_prefix, file);
4299                show_rename_copy(file, "rename", p, line_prefix);
4300                break;
4301        default:
4302                if (p->score) {
4303                        fprintf(file, "%s rewrite ", line_prefix);
4304                        write_name_quoted(p->two->path, file, ' ');
4305                        fprintf(file, "(%d%%)\n", similarity_index(p));
4306                }
4307                show_mode_change(file, p, !p->score, line_prefix);
4308                break;
4309        }
4310}
4311
4312struct patch_id_t {
4313        git_SHA_CTX *ctx;
4314        int patchlen;
4315};
4316
4317static int remove_space(char *line, int len)
4318{
4319        int i;
4320        char *dst = line;
4321        unsigned char c;
4322
4323        for (i = 0; i < len; i++)
4324                if (!isspace((c = line[i])))
4325                        *dst++ = c;
4326
4327        return dst - line;
4328}
4329
4330static void patch_id_consume(void *priv, char *line, unsigned long len)
4331{
4332        struct patch_id_t *data = priv;
4333        int new_len;
4334
4335        /* Ignore line numbers when computing the SHA1 of the patch */
4336        if (starts_with(line, "@@ -"))
4337                return;
4338
4339        new_len = remove_space(line, len);
4340
4341        git_SHA1_Update(data->ctx, line, new_len);
4342        data->patchlen += new_len;
4343}
4344
4345/* returns 0 upon success, and writes result into sha1 */
4346static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4347{
4348        struct diff_queue_struct *q = &diff_queued_diff;
4349        int i;
4350        git_SHA_CTX ctx;
4351        struct patch_id_t data;
4352        char buffer[PATH_MAX * 4 + 20];
4353
4354        git_SHA1_Init(&ctx);
4355        memset(&data, 0, sizeof(struct patch_id_t));
4356        data.ctx = &ctx;
4357
4358        for (i = 0; i < q->nr; i++) {
4359                xpparam_t xpp;
4360                xdemitconf_t xecfg;
4361                mmfile_t mf1, mf2;
4362                struct diff_filepair *p = q->queue[i];
4363                int len1, len2;
4364
4365                memset(&xpp, 0, sizeof(xpp));
4366                memset(&xecfg, 0, sizeof(xecfg));
4367                if (p->status == 0)
4368                        return error("internal diff status error");
4369                if (p->status == DIFF_STATUS_UNKNOWN)
4370                        continue;
4371                if (diff_unmodified_pair(p))
4372                        continue;
4373                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4374                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4375                        continue;
4376                if (DIFF_PAIR_UNMERGED(p))
4377                        continue;
4378
4379                diff_fill_sha1_info(p->one);
4380                diff_fill_sha1_info(p->two);
4381                if (fill_mmfile(&mf1, p->one) < 0 ||
4382                                fill_mmfile(&mf2, p->two) < 0)
4383                        return error("unable to read files to diff");
4384
4385                len1 = remove_space(p->one->path, strlen(p->one->path));
4386                len2 = remove_space(p->two->path, strlen(p->two->path));
4387                if (p->one->mode == 0)
4388                        len1 = snprintf(buffer, sizeof(buffer),
4389                                        "diff--gita/%.*sb/%.*s"
4390                                        "newfilemode%06o"
4391                                        "---/dev/null"
4392                                        "+++b/%.*s",
4393                                        len1, p->one->path,
4394                                        len2, p->two->path,
4395                                        p->two->mode,
4396                                        len2, p->two->path);
4397                else if (p->two->mode == 0)
4398                        len1 = snprintf(buffer, sizeof(buffer),
4399                                        "diff--gita/%.*sb/%.*s"
4400                                        "deletedfilemode%06o"
4401                                        "---a/%.*s"
4402                                        "+++/dev/null",
4403                                        len1, p->one->path,
4404                                        len2, p->two->path,
4405                                        p->one->mode,
4406                                        len1, p->one->path);
4407                else
4408                        len1 = snprintf(buffer, sizeof(buffer),
4409                                        "diff--gita/%.*sb/%.*s"
4410                                        "---a/%.*s"
4411                                        "+++b/%.*s",
4412                                        len1, p->one->path,
4413                                        len2, p->two->path,
4414                                        len1, p->one->path,
4415                                        len2, p->two->path);
4416                git_SHA1_Update(&ctx, buffer, len1);
4417
4418                if (diff_filespec_is_binary(p->one) ||
4419                    diff_filespec_is_binary(p->two)) {
4420                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4421                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4422                        continue;
4423                }
4424
4425                xpp.flags = 0;
4426                xecfg.ctxlen = 3;
4427                xecfg.flags = 0;
4428                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4429                              &xpp, &xecfg);
4430        }
4431
4432        git_SHA1_Final(sha1, &ctx);
4433        return 0;
4434}
4435
4436int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4437{
4438        struct diff_queue_struct *q = &diff_queued_diff;
4439        int i;
4440        int result = diff_get_patch_id(options, sha1);
4441
4442        for (i = 0; i < q->nr; i++)
4443                diff_free_filepair(q->queue[i]);
4444
4445        free(q->queue);
4446        DIFF_QUEUE_CLEAR(q);
4447
4448        return result;
4449}
4450
4451static int is_summary_empty(const struct diff_queue_struct *q)
4452{
4453        int i;
4454
4455        for (i = 0; i < q->nr; i++) {
4456                const struct diff_filepair *p = q->queue[i];
4457
4458                switch (p->status) {
4459                case DIFF_STATUS_DELETED:
4460                case DIFF_STATUS_ADDED:
4461                case DIFF_STATUS_COPIED:
4462                case DIFF_STATUS_RENAMED:
4463                        return 0;
4464                default:
4465                        if (p->score)
4466                                return 0;
4467                        if (p->one->mode && p->two->mode &&
4468                            p->one->mode != p->two->mode)
4469                                return 0;
4470                        break;
4471                }
4472        }
4473        return 1;
4474}
4475
4476static const char rename_limit_warning[] =
4477"inexact rename detection was skipped due to too many files.";
4478
4479static const char degrade_cc_to_c_warning[] =
4480"only found copies from modified paths due to too many files.";
4481
4482static const char rename_limit_advice[] =
4483"you may want to set your %s variable to at least "
4484"%d and retry the command.";
4485
4486void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4487{
4488        if (degraded_cc)
4489                warning(degrade_cc_to_c_warning);
4490        else if (needed)
4491                warning(rename_limit_warning);
4492        else
4493                return;
4494        if (0 < needed && needed < 32767)
4495                warning(rename_limit_advice, varname, needed);
4496}
4497
4498void diff_flush(struct diff_options *options)
4499{
4500        struct diff_queue_struct *q = &diff_queued_diff;
4501        int i, output_format = options->output_format;
4502        int separator = 0;
4503        int dirstat_by_line = 0;
4504
4505        /*
4506         * Order: raw, stat, summary, patch
4507         * or:    name/name-status/checkdiff (other bits clear)
4508         */
4509        if (!q->nr)
4510                goto free_queue;
4511
4512        if (output_format & (DIFF_FORMAT_RAW |
4513                             DIFF_FORMAT_NAME |
4514                             DIFF_FORMAT_NAME_STATUS |
4515                             DIFF_FORMAT_CHECKDIFF)) {
4516                for (i = 0; i < q->nr; i++) {
4517                        struct diff_filepair *p = q->queue[i];
4518                        if (check_pair_status(p))
4519                                flush_one_pair(p, options);
4520                }
4521                separator++;
4522        }
4523
4524        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4525                dirstat_by_line = 1;
4526
4527        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4528            dirstat_by_line) {
4529                struct diffstat_t diffstat;
4530
4531                memset(&diffstat, 0, sizeof(struct diffstat_t));
4532                for (i = 0; i < q->nr; i++) {
4533                        struct diff_filepair *p = q->queue[i];
4534                        if (check_pair_status(p))
4535                                diff_flush_stat(p, options, &diffstat);
4536                }
4537                if (output_format & DIFF_FORMAT_NUMSTAT)
4538                        show_numstat(&diffstat, options);
4539                if (output_format & DIFF_FORMAT_DIFFSTAT)
4540                        show_stats(&diffstat, options);
4541                if (output_format & DIFF_FORMAT_SHORTSTAT)
4542                        show_shortstats(&diffstat, options);
4543                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4544                        show_dirstat_by_line(&diffstat, options);
4545                free_diffstat_info(&diffstat);
4546                separator++;
4547        }
4548        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4549                show_dirstat(options);
4550
4551        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4552                for (i = 0; i < q->nr; i++) {
4553                        diff_summary(options, q->queue[i]);
4554                }
4555                separator++;
4556        }
4557
4558        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4559            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4560            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4561                /*
4562                 * run diff_flush_patch for the exit status. setting
4563                 * options->file to /dev/null should be safe, because we
4564                 * aren't supposed to produce any output anyway.
4565                 */
4566                if (options->close_file)
4567                        fclose(options->file);
4568                options->file = fopen("/dev/null", "w");
4569                if (!options->file)
4570                        die_errno("Could not open /dev/null");
4571                options->close_file = 1;
4572                for (i = 0; i < q->nr; i++) {
4573                        struct diff_filepair *p = q->queue[i];
4574                        if (check_pair_status(p))
4575                                diff_flush_patch(p, options);
4576                        if (options->found_changes)
4577                                break;
4578                }
4579        }
4580
4581        if (output_format & DIFF_FORMAT_PATCH) {
4582                if (separator) {
4583                        fprintf(options->file, "%s%c",
4584                                diff_line_prefix(options),
4585                                options->line_termination);
4586                        if (options->stat_sep) {
4587                                /* attach patch instead of inline */
4588                                fputs(options->stat_sep, options->file);
4589                        }
4590                }
4591
4592                for (i = 0; i < q->nr; i++) {
4593                        struct diff_filepair *p = q->queue[i];
4594                        if (check_pair_status(p))
4595                                diff_flush_patch(p, options);
4596                }
4597        }
4598
4599        if (output_format & DIFF_FORMAT_CALLBACK)
4600                options->format_callback(q, options, options->format_callback_data);
4601
4602        for (i = 0; i < q->nr; i++)
4603                diff_free_filepair(q->queue[i]);
4604free_queue:
4605        free(q->queue);
4606        DIFF_QUEUE_CLEAR(q);
4607        if (options->close_file)
4608                fclose(options->file);
4609
4610        /*
4611         * Report the content-level differences with HAS_CHANGES;
4612         * diff_addremove/diff_change does not set the bit when
4613         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4614         */
4615        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4616                if (options->found_changes)
4617                        DIFF_OPT_SET(options, HAS_CHANGES);
4618                else
4619                        DIFF_OPT_CLR(options, HAS_CHANGES);
4620        }
4621}
4622
4623static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4624{
4625        return (((p->status == DIFF_STATUS_MODIFIED) &&
4626                 ((p->score &&
4627                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4628                  (!p->score &&
4629                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4630                ((p->status != DIFF_STATUS_MODIFIED) &&
4631                 filter_bit_tst(p->status, options)));
4632}
4633
4634static void diffcore_apply_filter(struct diff_options *options)
4635{
4636        int i;
4637        struct diff_queue_struct *q = &diff_queued_diff;
4638        struct diff_queue_struct outq;
4639
4640        DIFF_QUEUE_CLEAR(&outq);
4641
4642        if (!options->filter)
4643                return;
4644
4645        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4646                int found;
4647                for (i = found = 0; !found && i < q->nr; i++) {
4648                        if (match_filter(options, q->queue[i]))
4649                                found++;
4650                }
4651                if (found)
4652                        return;
4653
4654                /* otherwise we will clear the whole queue
4655                 * by copying the empty outq at the end of this
4656                 * function, but first clear the current entries
4657                 * in the queue.
4658                 */
4659                for (i = 0; i < q->nr; i++)
4660                        diff_free_filepair(q->queue[i]);
4661        }
4662        else {
4663                /* Only the matching ones */
4664                for (i = 0; i < q->nr; i++) {
4665                        struct diff_filepair *p = q->queue[i];
4666                        if (match_filter(options, p))
4667                                diff_q(&outq, p);
4668                        else
4669                                diff_free_filepair(p);
4670                }
4671        }
4672        free(q->queue);
4673        *q = outq;
4674}
4675
4676/* Check whether two filespecs with the same mode and size are identical */
4677static int diff_filespec_is_identical(struct diff_filespec *one,
4678                                      struct diff_filespec *two)
4679{
4680        if (S_ISGITLINK(one->mode))
4681                return 0;
4682        if (diff_populate_filespec(one, 0))
4683                return 0;
4684        if (diff_populate_filespec(two, 0))
4685                return 0;
4686        return !memcmp(one->data, two->data, one->size);
4687}
4688
4689static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4690{
4691        if (p->done_skip_stat_unmatch)
4692                return p->skip_stat_unmatch_result;
4693
4694        p->done_skip_stat_unmatch = 1;
4695        p->skip_stat_unmatch_result = 0;
4696        /*
4697         * 1. Entries that come from stat info dirtiness
4698         *    always have both sides (iow, not create/delete),
4699         *    one side of the object name is unknown, with
4700         *    the same mode and size.  Keep the ones that
4701         *    do not match these criteria.  They have real
4702         *    differences.
4703         *
4704         * 2. At this point, the file is known to be modified,
4705         *    with the same mode and size, and the object
4706         *    name of one side is unknown.  Need to inspect
4707         *    the identical contents.
4708         */
4709        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4710            !DIFF_FILE_VALID(p->two) ||
4711            (p->one->sha1_valid && p->two->sha1_valid) ||
4712            (p->one->mode != p->two->mode) ||
4713            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4714            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4715            (p->one->size != p->two->size) ||
4716            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4717                p->skip_stat_unmatch_result = 1;
4718        return p->skip_stat_unmatch_result;
4719}
4720
4721static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4722{
4723        int i;
4724        struct diff_queue_struct *q = &diff_queued_diff;
4725        struct diff_queue_struct outq;
4726        DIFF_QUEUE_CLEAR(&outq);
4727
4728        for (i = 0; i < q->nr; i++) {
4729                struct diff_filepair *p = q->queue[i];
4730
4731                if (diff_filespec_check_stat_unmatch(p))
4732                        diff_q(&outq, p);
4733                else {
4734                        /*
4735                         * The caller can subtract 1 from skip_stat_unmatch
4736                         * to determine how many paths were dirty only
4737                         * due to stat info mismatch.
4738                         */
4739                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4740                                diffopt->skip_stat_unmatch++;
4741                        diff_free_filepair(p);
4742                }
4743        }
4744        free(q->queue);
4745        *q = outq;
4746}
4747
4748static int diffnamecmp(const void *a_, const void *b_)
4749{
4750        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4751        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4752        const char *name_a, *name_b;
4753
4754        name_a = a->one ? a->one->path : a->two->path;
4755        name_b = b->one ? b->one->path : b->two->path;
4756        return strcmp(name_a, name_b);
4757}
4758
4759void diffcore_fix_diff_index(struct diff_options *options)
4760{
4761        struct diff_queue_struct *q = &diff_queued_diff;
4762        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4763}
4764
4765void diffcore_std(struct diff_options *options)
4766{
4767        /* NOTE please keep the following in sync with diff_tree_combined() */
4768        if (options->skip_stat_unmatch)
4769                diffcore_skip_stat_unmatch(options);
4770        if (!options->found_follow) {
4771                /* See try_to_follow_renames() in tree-diff.c */
4772                if (options->break_opt != -1)
4773                        diffcore_break(options->break_opt);
4774                if (options->detect_rename)
4775                        diffcore_rename(options);
4776                if (options->break_opt != -1)
4777                        diffcore_merge_broken();
4778        }
4779        if (options->pickaxe)
4780                diffcore_pickaxe(options);
4781        if (options->orderfile)
4782                diffcore_order(options->orderfile);
4783        if (!options->found_follow)
4784                /* See try_to_follow_renames() in tree-diff.c */
4785                diff_resolve_rename_copy();
4786        diffcore_apply_filter(options);
4787
4788        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4789                DIFF_OPT_SET(options, HAS_CHANGES);
4790        else
4791                DIFF_OPT_CLR(options, HAS_CHANGES);
4792
4793        options->found_follow = 0;
4794}
4795
4796int diff_result_code(struct diff_options *opt, int status)
4797{
4798        int result = 0;
4799
4800        diff_warn_rename_limit("diff.renameLimit",
4801                               opt->needed_rename_limit,
4802                               opt->degraded_cc_to_c);
4803        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4804            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4805                return status;
4806        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4807            DIFF_OPT_TST(opt, HAS_CHANGES))
4808                result |= 01;
4809        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4810            DIFF_OPT_TST(opt, CHECK_FAILED))
4811                result |= 02;
4812        return result;
4813}
4814
4815int diff_can_quit_early(struct diff_options *opt)
4816{
4817        return (DIFF_OPT_TST(opt, QUICK) &&
4818                !opt->filter &&
4819                DIFF_OPT_TST(opt, HAS_CHANGES));
4820}
4821
4822/*
4823 * Shall changes to this submodule be ignored?
4824 *
4825 * Submodule changes can be configured to be ignored separately for each path,
4826 * but that configuration can be overridden from the command line.
4827 */
4828static int is_submodule_ignored(const char *path, struct diff_options *options)
4829{
4830        int ignored = 0;
4831        unsigned orig_flags = options->flags;
4832        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4833                set_diffopt_flags_from_submodule_config(options, path);
4834        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4835                ignored = 1;
4836        options->flags = orig_flags;
4837        return ignored;
4838}
4839
4840void diff_addremove(struct diff_options *options,
4841                    int addremove, unsigned mode,
4842                    const unsigned char *sha1,
4843                    int sha1_valid,
4844                    const char *concatpath, unsigned dirty_submodule)
4845{
4846        struct diff_filespec *one, *two;
4847
4848        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4849                return;
4850
4851        /* This may look odd, but it is a preparation for
4852         * feeding "there are unchanged files which should
4853         * not produce diffs, but when you are doing copy
4854         * detection you would need them, so here they are"
4855         * entries to the diff-core.  They will be prefixed
4856         * with something like '=' or '*' (I haven't decided
4857         * which but should not make any difference).
4858         * Feeding the same new and old to diff_change()
4859         * also has the same effect.
4860         * Before the final output happens, they are pruned after
4861         * merged into rename/copy pairs as appropriate.
4862         */
4863        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4864                addremove = (addremove == '+' ? '-' :
4865                             addremove == '-' ? '+' : addremove);
4866
4867        if (options->prefix &&
4868            strncmp(concatpath, options->prefix, options->prefix_length))
4869                return;
4870
4871        one = alloc_filespec(concatpath);
4872        two = alloc_filespec(concatpath);
4873
4874        if (addremove != '+')
4875                fill_filespec(one, sha1, sha1_valid, mode);
4876        if (addremove != '-') {
4877                fill_filespec(two, sha1, sha1_valid, mode);
4878                two->dirty_submodule = dirty_submodule;
4879        }
4880
4881        diff_queue(&diff_queued_diff, one, two);
4882        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4883                DIFF_OPT_SET(options, HAS_CHANGES);
4884}
4885
4886void diff_change(struct diff_options *options,
4887                 unsigned old_mode, unsigned new_mode,
4888                 const unsigned char *old_sha1,
4889                 const unsigned char *new_sha1,
4890                 int old_sha1_valid, int new_sha1_valid,
4891                 const char *concatpath,
4892                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4893{
4894        struct diff_filespec *one, *two;
4895        struct diff_filepair *p;
4896
4897        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4898            is_submodule_ignored(concatpath, options))
4899                return;
4900
4901        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4902                unsigned tmp;
4903                const unsigned char *tmp_c;
4904                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4905                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4906                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4907                        new_sha1_valid = tmp;
4908                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4909                        new_dirty_submodule = tmp;
4910        }
4911
4912        if (options->prefix &&
4913            strncmp(concatpath, options->prefix, options->prefix_length))
4914                return;
4915
4916        one = alloc_filespec(concatpath);
4917        two = alloc_filespec(concatpath);
4918        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4919        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4920        one->dirty_submodule = old_dirty_submodule;
4921        two->dirty_submodule = new_dirty_submodule;
4922        p = diff_queue(&diff_queued_diff, one, two);
4923
4924        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4925                return;
4926
4927        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
4928            !diff_filespec_check_stat_unmatch(p))
4929                return;
4930
4931        DIFF_OPT_SET(options, HAS_CHANGES);
4932}
4933
4934struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4935{
4936        struct diff_filepair *pair;
4937        struct diff_filespec *one, *two;
4938
4939        if (options->prefix &&
4940            strncmp(path, options->prefix, options->prefix_length))
4941                return NULL;
4942
4943        one = alloc_filespec(path);
4944        two = alloc_filespec(path);
4945        pair = diff_queue(&diff_queued_diff, one, two);
4946        pair->is_unmerged = 1;
4947        return pair;
4948}
4949
4950static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4951                size_t *outsize)
4952{
4953        struct diff_tempfile *temp;
4954        const char *argv[3];
4955        const char **arg = argv;
4956        struct child_process child = CHILD_PROCESS_INIT;
4957        struct strbuf buf = STRBUF_INIT;
4958        int err = 0;
4959
4960        temp = prepare_temp_file(spec->path, spec);
4961        *arg++ = pgm;
4962        *arg++ = temp->name;
4963        *arg = NULL;
4964
4965        child.use_shell = 1;
4966        child.argv = argv;
4967        child.out = -1;
4968        if (start_command(&child)) {
4969                remove_tempfile();
4970                return NULL;
4971        }
4972
4973        if (strbuf_read(&buf, child.out, 0) < 0)
4974                err = error("error reading from textconv command '%s'", pgm);
4975        close(child.out);
4976
4977        if (finish_command(&child) || err) {
4978                strbuf_release(&buf);
4979                remove_tempfile();
4980                return NULL;
4981        }
4982        remove_tempfile();
4983
4984        return strbuf_detach(&buf, outsize);
4985}
4986
4987size_t fill_textconv(struct userdiff_driver *driver,
4988                     struct diff_filespec *df,
4989                     char **outbuf)
4990{
4991        size_t size;
4992
4993        if (!driver || !driver->textconv) {
4994                if (!DIFF_FILE_VALID(df)) {
4995                        *outbuf = "";
4996                        return 0;
4997                }
4998                if (diff_populate_filespec(df, 0))
4999                        die("unable to read files to diff");
5000                *outbuf = df->data;
5001                return df->size;
5002        }
5003
5004        if (driver->textconv_cache && df->sha1_valid) {
5005                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5006                                          &size);
5007                if (*outbuf)
5008                        return size;
5009        }
5010
5011        *outbuf = run_textconv(driver->textconv, df, &size);
5012        if (!*outbuf)
5013                die("unable to read files to diff");
5014
5015        if (driver->textconv_cache && df->sha1_valid) {
5016                /* ignore errors, as we might be in a readonly repository */
5017                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5018                                size);
5019                /*
5020                 * we could save up changes and flush them all at the end,
5021                 * but we would need an extra call after all diffing is done.
5022                 * Since generating a cache entry is the slow path anyway,
5023                 * this extra overhead probably isn't a big deal.
5024                 */
5025                notes_cache_write(driver->textconv_cache);
5026        }
5027
5028        return size;
5029}
5030
5031void setup_diff_pager(struct diff_options *opt)
5032{
5033        /*
5034         * If the user asked for our exit code, then either they want --quiet
5035         * or --exit-code. We should definitely not bother with a pager in the
5036         * former case, as we will generate no output. Since we still properly
5037         * report our exit code even when a pager is run, we _could_ run a
5038         * pager with --exit-code. But since we have not done so historically,
5039         * and because it is easy to find people oneline advising "git diff
5040         * --exit-code" in hooks and other scripts, we do not do so.
5041         */
5042        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5043            check_pager_config("diff") != 0)
5044                setup_pager();
5045}