diff.con commit submodule: allow erroneous values for the fetchRecurseSubmodules option (027771f)
   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-config.h"
  17#include "submodule.h"
  18#include "ll-merge.h"
  19#include "string-list.h"
  20#include "argv-array.h"
  21
  22#ifdef NO_FAST_WORKING_DIRECTORY
  23#define FAST_WORKING_DIRECTORY 0
  24#else
  25#define FAST_WORKING_DIRECTORY 1
  26#endif
  27
  28static int diff_detect_rename_default;
  29static int diff_rename_limit_default = 400;
  30static int diff_suppress_blank_empty;
  31static int diff_use_color_default = -1;
  32static int diff_context_default = 3;
  33static const char *diff_word_regex_cfg;
  34static const char *external_diff_cmd_cfg;
  35static const char *diff_order_file_cfg;
  36int diff_auto_refresh_index = 1;
  37static int diff_mnemonic_prefix;
  38static int diff_no_prefix;
  39static int diff_stat_graph_width;
  40static int diff_dirstat_permille_default = 30;
  41static struct diff_options default_diff_options;
  42static long diff_algorithm;
  43
  44static char diff_colors[][COLOR_MAXLEN] = {
  45        GIT_COLOR_RESET,
  46        GIT_COLOR_NORMAL,       /* PLAIN */
  47        GIT_COLOR_BOLD,         /* METAINFO */
  48        GIT_COLOR_CYAN,         /* FRAGINFO */
  49        GIT_COLOR_RED,          /* OLD */
  50        GIT_COLOR_GREEN,        /* NEW */
  51        GIT_COLOR_YELLOW,       /* COMMIT */
  52        GIT_COLOR_BG_RED,       /* WHITESPACE */
  53        GIT_COLOR_NORMAL,       /* FUNCINFO */
  54};
  55
  56static int parse_diff_color_slot(const char *var)
  57{
  58        if (!strcasecmp(var, "plain"))
  59                return DIFF_PLAIN;
  60        if (!strcasecmp(var, "meta"))
  61                return DIFF_METAINFO;
  62        if (!strcasecmp(var, "frag"))
  63                return DIFF_FRAGINFO;
  64        if (!strcasecmp(var, "old"))
  65                return DIFF_FILE_OLD;
  66        if (!strcasecmp(var, "new"))
  67                return DIFF_FILE_NEW;
  68        if (!strcasecmp(var, "commit"))
  69                return DIFF_COMMIT;
  70        if (!strcasecmp(var, "whitespace"))
  71                return DIFF_WHITESPACE;
  72        if (!strcasecmp(var, "func"))
  73                return DIFF_FUNCINFO;
  74        return -1;
  75}
  76
  77static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  78                                struct strbuf *errmsg)
  79{
  80        char *params_copy = xstrdup(params_string);
  81        struct string_list params = STRING_LIST_INIT_NODUP;
  82        int ret = 0;
  83        int i;
  84
  85        if (*params_copy)
  86                string_list_split_in_place(&params, params_copy, ',', -1);
  87        for (i = 0; i < params.nr; i++) {
  88                const char *p = params.items[i].string;
  89                if (!strcmp(p, "changes")) {
  90                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  91                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  92                } else if (!strcmp(p, "lines")) {
  93                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  94                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  95                } else if (!strcmp(p, "files")) {
  96                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  97                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  98                } else if (!strcmp(p, "noncumulative")) {
  99                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 100                } else if (!strcmp(p, "cumulative")) {
 101                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 102                } else if (isdigit(*p)) {
 103                        char *end;
 104                        int permille = strtoul(p, &end, 10) * 10;
 105                        if (*end == '.' && isdigit(*++end)) {
 106                                /* only use first digit */
 107                                permille += *end - '0';
 108                                /* .. and ignore any further digits */
 109                                while (isdigit(*++end))
 110                                        ; /* nothing */
 111                        }
 112                        if (!*end)
 113                                options->dirstat_permille = permille;
 114                        else {
 115                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 116                                            p);
 117                                ret++;
 118                        }
 119                } else {
 120                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 121                        ret++;
 122                }
 123
 124        }
 125        string_list_clear(&params, 0);
 126        free(params_copy);
 127        return ret;
 128}
 129
 130static int parse_submodule_params(struct diff_options *options, const char *value)
 131{
 132        if (!strcmp(value, "log"))
 133                DIFF_OPT_SET(options, SUBMODULE_LOG);
 134        else if (!strcmp(value, "short"))
 135                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 136        else
 137                return -1;
 138        return 0;
 139}
 140
 141static int git_config_rename(const char *var, const char *value)
 142{
 143        if (!value)
 144                return DIFF_DETECT_RENAME;
 145        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 146                return  DIFF_DETECT_COPY;
 147        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 148}
 149
 150long parse_algorithm_value(const char *value)
 151{
 152        if (!value)
 153                return -1;
 154        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 155                return 0;
 156        else if (!strcasecmp(value, "minimal"))
 157                return XDF_NEED_MINIMAL;
 158        else if (!strcasecmp(value, "patience"))
 159                return XDF_PATIENCE_DIFF;
 160        else if (!strcasecmp(value, "histogram"))
 161                return XDF_HISTOGRAM_DIFF;
 162        return -1;
 163}
 164
 165/*
 166 * These are to give UI layer defaults.
 167 * The core-level commands such as git-diff-files should
 168 * never be affected by the setting of diff.renames
 169 * the user happens to have in the configuration file.
 170 */
 171int git_diff_ui_config(const char *var, const char *value, void *cb)
 172{
 173        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 174                diff_use_color_default = git_config_colorbool(var, value);
 175                return 0;
 176        }
 177        if (!strcmp(var, "diff.context")) {
 178                diff_context_default = git_config_int(var, value);
 179                if (diff_context_default < 0)
 180                        return -1;
 181                return 0;
 182        }
 183        if (!strcmp(var, "diff.renames")) {
 184                diff_detect_rename_default = git_config_rename(var, value);
 185                return 0;
 186        }
 187        if (!strcmp(var, "diff.autorefreshindex")) {
 188                diff_auto_refresh_index = git_config_bool(var, value);
 189                return 0;
 190        }
 191        if (!strcmp(var, "diff.mnemonicprefix")) {
 192                diff_mnemonic_prefix = git_config_bool(var, value);
 193                return 0;
 194        }
 195        if (!strcmp(var, "diff.noprefix")) {
 196                diff_no_prefix = git_config_bool(var, value);
 197                return 0;
 198        }
 199        if (!strcmp(var, "diff.statgraphwidth")) {
 200                diff_stat_graph_width = git_config_int(var, value);
 201                return 0;
 202        }
 203        if (!strcmp(var, "diff.external"))
 204                return git_config_string(&external_diff_cmd_cfg, var, value);
 205        if (!strcmp(var, "diff.wordregex"))
 206                return git_config_string(&diff_word_regex_cfg, var, value);
 207        if (!strcmp(var, "diff.orderfile"))
 208                return git_config_pathname(&diff_order_file_cfg, var, value);
 209
 210        if (!strcmp(var, "diff.ignoresubmodules"))
 211                handle_ignore_submodules_arg(&default_diff_options, value);
 212
 213        if (!strcmp(var, "diff.submodule")) {
 214                if (parse_submodule_params(&default_diff_options, value))
 215                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 216                                value);
 217                return 0;
 218        }
 219
 220        if (!strcmp(var, "diff.algorithm")) {
 221                diff_algorithm = parse_algorithm_value(value);
 222                if (diff_algorithm < 0)
 223                        return -1;
 224                return 0;
 225        }
 226
 227        if (git_color_config(var, value, cb) < 0)
 228                return -1;
 229
 230        return git_diff_basic_config(var, value, cb);
 231}
 232
 233int git_diff_basic_config(const char *var, const char *value, void *cb)
 234{
 235        const char *name;
 236
 237        if (!strcmp(var, "diff.renamelimit")) {
 238                diff_rename_limit_default = git_config_int(var, value);
 239                return 0;
 240        }
 241
 242        if (userdiff_config(var, value) < 0)
 243                return -1;
 244
 245        if (skip_prefix(var, "diff.color.", &name) ||
 246            skip_prefix(var, "color.diff.", &name)) {
 247                int slot = parse_diff_color_slot(name);
 248                if (slot < 0)
 249                        return 0;
 250                if (!value)
 251                        return config_error_nonbool(var);
 252                return color_parse(value, diff_colors[slot]);
 253        }
 254
 255        /* like GNU diff's --suppress-blank-empty option  */
 256        if (!strcmp(var, "diff.suppressblankempty") ||
 257                        /* for backwards compatibility */
 258                        !strcmp(var, "diff.suppress-blank-empty")) {
 259                diff_suppress_blank_empty = git_config_bool(var, value);
 260                return 0;
 261        }
 262
 263        if (!strcmp(var, "diff.dirstat")) {
 264                struct strbuf errmsg = STRBUF_INIT;
 265                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 266                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 267                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 268                                errmsg.buf);
 269                strbuf_release(&errmsg);
 270                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 271                return 0;
 272        }
 273
 274        if (starts_with(var, "submodule."))
 275                return parse_submodule_config_option(var, value);
 276
 277        return git_default_config(var, value, cb);
 278}
 279
 280static char *quote_two(const char *one, const char *two)
 281{
 282        int need_one = quote_c_style(one, NULL, NULL, 1);
 283        int need_two = quote_c_style(two, NULL, NULL, 1);
 284        struct strbuf res = STRBUF_INIT;
 285
 286        if (need_one + need_two) {
 287                strbuf_addch(&res, '"');
 288                quote_c_style(one, &res, NULL, 1);
 289                quote_c_style(two, &res, NULL, 1);
 290                strbuf_addch(&res, '"');
 291        } else {
 292                strbuf_addstr(&res, one);
 293                strbuf_addstr(&res, two);
 294        }
 295        return strbuf_detach(&res, NULL);
 296}
 297
 298static const char *external_diff(void)
 299{
 300        static const char *external_diff_cmd = NULL;
 301        static int done_preparing = 0;
 302
 303        if (done_preparing)
 304                return external_diff_cmd;
 305        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 306        if (!external_diff_cmd)
 307                external_diff_cmd = external_diff_cmd_cfg;
 308        done_preparing = 1;
 309        return external_diff_cmd;
 310}
 311
 312static struct diff_tempfile {
 313        const char *name; /* filename external diff should read from */
 314        char hex[41];
 315        char mode[10];
 316        char tmp_path[PATH_MAX];
 317} diff_temp[2];
 318
 319typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 320
 321struct emit_callback {
 322        int color_diff;
 323        unsigned ws_rule;
 324        int blank_at_eof_in_preimage;
 325        int blank_at_eof_in_postimage;
 326        int lno_in_preimage;
 327        int lno_in_postimage;
 328        sane_truncate_fn truncate;
 329        const char **label_path;
 330        struct diff_words_data *diff_words;
 331        struct diff_options *opt;
 332        int *found_changesp;
 333        struct strbuf *header;
 334};
 335
 336static int count_lines(const char *data, int size)
 337{
 338        int count, ch, completely_empty = 1, nl_just_seen = 0;
 339        count = 0;
 340        while (0 < size--) {
 341                ch = *data++;
 342                if (ch == '\n') {
 343                        count++;
 344                        nl_just_seen = 1;
 345                        completely_empty = 0;
 346                }
 347                else {
 348                        nl_just_seen = 0;
 349                        completely_empty = 0;
 350                }
 351        }
 352        if (completely_empty)
 353                return 0;
 354        if (!nl_just_seen)
 355                count++; /* no trailing newline */
 356        return count;
 357}
 358
 359static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 360{
 361        if (!DIFF_FILE_VALID(one)) {
 362                mf->ptr = (char *)""; /* does not matter */
 363                mf->size = 0;
 364                return 0;
 365        }
 366        else if (diff_populate_filespec(one, 0))
 367                return -1;
 368
 369        mf->ptr = one->data;
 370        mf->size = one->size;
 371        return 0;
 372}
 373
 374/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 375static unsigned long diff_filespec_size(struct diff_filespec *one)
 376{
 377        if (!DIFF_FILE_VALID(one))
 378                return 0;
 379        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 380        return one->size;
 381}
 382
 383static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 384{
 385        char *ptr = mf->ptr;
 386        long size = mf->size;
 387        int cnt = 0;
 388
 389        if (!size)
 390                return cnt;
 391        ptr += size - 1; /* pointing at the very end */
 392        if (*ptr != '\n')
 393                ; /* incomplete line */
 394        else
 395                ptr--; /* skip the last LF */
 396        while (mf->ptr < ptr) {
 397                char *prev_eol;
 398                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 399                        if (*prev_eol == '\n')
 400                                break;
 401                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 402                        break;
 403                cnt++;
 404                ptr = prev_eol - 1;
 405        }
 406        return cnt;
 407}
 408
 409static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 410                               struct emit_callback *ecbdata)
 411{
 412        int l1, l2, at;
 413        unsigned ws_rule = ecbdata->ws_rule;
 414        l1 = count_trailing_blank(mf1, ws_rule);
 415        l2 = count_trailing_blank(mf2, ws_rule);
 416        if (l2 <= l1) {
 417                ecbdata->blank_at_eof_in_preimage = 0;
 418                ecbdata->blank_at_eof_in_postimage = 0;
 419                return;
 420        }
 421        at = count_lines(mf1->ptr, mf1->size);
 422        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 423
 424        at = count_lines(mf2->ptr, mf2->size);
 425        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 426}
 427
 428static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 429                        int first, const char *line, int len)
 430{
 431        int has_trailing_newline, has_trailing_carriage_return;
 432        int nofirst;
 433        FILE *file = o->file;
 434
 435        fputs(diff_line_prefix(o), file);
 436
 437        if (len == 0) {
 438                has_trailing_newline = (first == '\n');
 439                has_trailing_carriage_return = (!has_trailing_newline &&
 440                                                (first == '\r'));
 441                nofirst = has_trailing_newline || has_trailing_carriage_return;
 442        } else {
 443                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 444                if (has_trailing_newline)
 445                        len--;
 446                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 447                if (has_trailing_carriage_return)
 448                        len--;
 449                nofirst = 0;
 450        }
 451
 452        if (len || !nofirst) {
 453                fputs(set, file);
 454                if (!nofirst)
 455                        fputc(first, file);
 456                fwrite(line, len, 1, file);
 457                fputs(reset, file);
 458        }
 459        if (has_trailing_carriage_return)
 460                fputc('\r', file);
 461        if (has_trailing_newline)
 462                fputc('\n', file);
 463}
 464
 465static void emit_line(struct diff_options *o, const char *set, const char *reset,
 466                      const char *line, int len)
 467{
 468        emit_line_0(o, set, reset, line[0], line+1, len-1);
 469}
 470
 471static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 472{
 473        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 474              ecbdata->blank_at_eof_in_preimage &&
 475              ecbdata->blank_at_eof_in_postimage &&
 476              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 477              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 478                return 0;
 479        return ws_blank_line(line, len, ecbdata->ws_rule);
 480}
 481
 482static void emit_add_line(const char *reset,
 483                          struct emit_callback *ecbdata,
 484                          const char *line, int len)
 485{
 486        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 487        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 488
 489        if (!*ws)
 490                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 491        else if (new_blank_line_at_eof(ecbdata, line, len))
 492                /* Blank line at EOF - paint '+' as well */
 493                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 494        else {
 495                /* Emit just the prefix, then the rest. */
 496                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 497                ws_check_emit(line, len, ecbdata->ws_rule,
 498                              ecbdata->opt->file, set, reset, ws);
 499        }
 500}
 501
 502static void emit_hunk_header(struct emit_callback *ecbdata,
 503                             const char *line, int len)
 504{
 505        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 506        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 507        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 508        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 509        static const char atat[2] = { '@', '@' };
 510        const char *cp, *ep;
 511        struct strbuf msgbuf = STRBUF_INIT;
 512        int org_len = len;
 513        int i = 1;
 514
 515        /*
 516         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 517         * it always is at least 10 bytes long.
 518         */
 519        if (len < 10 ||
 520            memcmp(line, atat, 2) ||
 521            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 522                emit_line(ecbdata->opt, plain, reset, line, len);
 523                return;
 524        }
 525        ep += 2; /* skip over @@ */
 526
 527        /* The hunk header in fraginfo color */
 528        strbuf_addstr(&msgbuf, frag);
 529        strbuf_add(&msgbuf, line, ep - line);
 530        strbuf_addstr(&msgbuf, reset);
 531
 532        /*
 533         * trailing "\r\n"
 534         */
 535        for ( ; i < 3; i++)
 536                if (line[len - i] == '\r' || line[len - i] == '\n')
 537                        len--;
 538
 539        /* blank before the func header */
 540        for (cp = ep; ep - line < len; ep++)
 541                if (*ep != ' ' && *ep != '\t')
 542                        break;
 543        if (ep != cp) {
 544                strbuf_addstr(&msgbuf, plain);
 545                strbuf_add(&msgbuf, cp, ep - cp);
 546                strbuf_addstr(&msgbuf, reset);
 547        }
 548
 549        if (ep < line + len) {
 550                strbuf_addstr(&msgbuf, func);
 551                strbuf_add(&msgbuf, ep, line + len - ep);
 552                strbuf_addstr(&msgbuf, reset);
 553        }
 554
 555        strbuf_add(&msgbuf, line + len, org_len - len);
 556        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 557        strbuf_release(&msgbuf);
 558}
 559
 560static struct diff_tempfile *claim_diff_tempfile(void) {
 561        int i;
 562        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 563                if (!diff_temp[i].name)
 564                        return diff_temp + i;
 565        die("BUG: diff is failing to clean up its tempfiles");
 566}
 567
 568static int remove_tempfile_installed;
 569
 570static void remove_tempfile(void)
 571{
 572        int i;
 573        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 574                if (diff_temp[i].name == diff_temp[i].tmp_path)
 575                        unlink_or_warn(diff_temp[i].name);
 576                diff_temp[i].name = NULL;
 577        }
 578}
 579
 580static void remove_tempfile_on_signal(int signo)
 581{
 582        remove_tempfile();
 583        sigchain_pop(signo);
 584        raise(signo);
 585}
 586
 587static void print_line_count(FILE *file, int count)
 588{
 589        switch (count) {
 590        case 0:
 591                fprintf(file, "0,0");
 592                break;
 593        case 1:
 594                fprintf(file, "1");
 595                break;
 596        default:
 597                fprintf(file, "1,%d", count);
 598                break;
 599        }
 600}
 601
 602static void emit_rewrite_lines(struct emit_callback *ecb,
 603                               int prefix, const char *data, int size)
 604{
 605        const char *endp = NULL;
 606        static const char *nneof = " No newline at end of file\n";
 607        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 608        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 609
 610        while (0 < size) {
 611                int len;
 612
 613                endp = memchr(data, '\n', size);
 614                len = endp ? (endp - data + 1) : size;
 615                if (prefix != '+') {
 616                        ecb->lno_in_preimage++;
 617                        emit_line_0(ecb->opt, old, reset, '-',
 618                                    data, len);
 619                } else {
 620                        ecb->lno_in_postimage++;
 621                        emit_add_line(reset, ecb, data, len);
 622                }
 623                size -= len;
 624                data += len;
 625        }
 626        if (!endp) {
 627                const char *plain = diff_get_color(ecb->color_diff,
 628                                                   DIFF_PLAIN);
 629                putc('\n', ecb->opt->file);
 630                emit_line_0(ecb->opt, plain, reset, '\\',
 631                            nneof, strlen(nneof));
 632        }
 633}
 634
 635static void emit_rewrite_diff(const char *name_a,
 636                              const char *name_b,
 637                              struct diff_filespec *one,
 638                              struct diff_filespec *two,
 639                              struct userdiff_driver *textconv_one,
 640                              struct userdiff_driver *textconv_two,
 641                              struct diff_options *o)
 642{
 643        int lc_a, lc_b;
 644        const char *name_a_tab, *name_b_tab;
 645        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 646        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 647        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 648        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 649        const char *a_prefix, *b_prefix;
 650        char *data_one, *data_two;
 651        size_t size_one, size_two;
 652        struct emit_callback ecbdata;
 653        const char *line_prefix = diff_line_prefix(o);
 654
 655        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 656                a_prefix = o->b_prefix;
 657                b_prefix = o->a_prefix;
 658        } else {
 659                a_prefix = o->a_prefix;
 660                b_prefix = o->b_prefix;
 661        }
 662
 663        name_a += (*name_a == '/');
 664        name_b += (*name_b == '/');
 665        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 666        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 667
 668        strbuf_reset(&a_name);
 669        strbuf_reset(&b_name);
 670        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 671        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 672
 673        size_one = fill_textconv(textconv_one, one, &data_one);
 674        size_two = fill_textconv(textconv_two, two, &data_two);
 675
 676        memset(&ecbdata, 0, sizeof(ecbdata));
 677        ecbdata.color_diff = want_color(o->use_color);
 678        ecbdata.found_changesp = &o->found_changes;
 679        ecbdata.ws_rule = whitespace_rule(name_b);
 680        ecbdata.opt = o;
 681        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 682                mmfile_t mf1, mf2;
 683                mf1.ptr = (char *)data_one;
 684                mf2.ptr = (char *)data_two;
 685                mf1.size = size_one;
 686                mf2.size = size_two;
 687                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 688        }
 689        ecbdata.lno_in_preimage = 1;
 690        ecbdata.lno_in_postimage = 1;
 691
 692        lc_a = count_lines(data_one, size_one);
 693        lc_b = count_lines(data_two, size_two);
 694        fprintf(o->file,
 695                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 696                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 697                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 698                line_prefix, fraginfo);
 699        if (!o->irreversible_delete)
 700                print_line_count(o->file, lc_a);
 701        else
 702                fprintf(o->file, "?,?");
 703        fprintf(o->file, " +");
 704        print_line_count(o->file, lc_b);
 705        fprintf(o->file, " @@%s\n", reset);
 706        if (lc_a && !o->irreversible_delete)
 707                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 708        if (lc_b)
 709                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 710        if (textconv_one)
 711                free((char *)data_one);
 712        if (textconv_two)
 713                free((char *)data_two);
 714}
 715
 716struct diff_words_buffer {
 717        mmfile_t text;
 718        long alloc;
 719        struct diff_words_orig {
 720                const char *begin, *end;
 721        } *orig;
 722        int orig_nr, orig_alloc;
 723};
 724
 725static void diff_words_append(char *line, unsigned long len,
 726                struct diff_words_buffer *buffer)
 727{
 728        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 729        line++;
 730        len--;
 731        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 732        buffer->text.size += len;
 733        buffer->text.ptr[buffer->text.size] = '\0';
 734}
 735
 736struct diff_words_style_elem {
 737        const char *prefix;
 738        const char *suffix;
 739        const char *color; /* NULL; filled in by the setup code if
 740                            * color is enabled */
 741};
 742
 743struct diff_words_style {
 744        enum diff_words_type type;
 745        struct diff_words_style_elem new, old, ctx;
 746        const char *newline;
 747};
 748
 749static struct diff_words_style diff_words_styles[] = {
 750        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 751        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 752        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 753};
 754
 755struct diff_words_data {
 756        struct diff_words_buffer minus, plus;
 757        const char *current_plus;
 758        int last_minus;
 759        struct diff_options *opt;
 760        regex_t *word_regex;
 761        enum diff_words_type type;
 762        struct diff_words_style *style;
 763};
 764
 765static int fn_out_diff_words_write_helper(FILE *fp,
 766                                          struct diff_words_style_elem *st_el,
 767                                          const char *newline,
 768                                          size_t count, const char *buf,
 769                                          const char *line_prefix)
 770{
 771        int print = 0;
 772
 773        while (count) {
 774                char *p = memchr(buf, '\n', count);
 775                if (print)
 776                        fputs(line_prefix, fp);
 777                if (p != buf) {
 778                        if (st_el->color && fputs(st_el->color, fp) < 0)
 779                                return -1;
 780                        if (fputs(st_el->prefix, fp) < 0 ||
 781                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 782                            fputs(st_el->suffix, fp) < 0)
 783                                return -1;
 784                        if (st_el->color && *st_el->color
 785                            && fputs(GIT_COLOR_RESET, fp) < 0)
 786                                return -1;
 787                }
 788                if (!p)
 789                        return 0;
 790                if (fputs(newline, fp) < 0)
 791                        return -1;
 792                count -= p + 1 - buf;
 793                buf = p + 1;
 794                print = 1;
 795        }
 796        return 0;
 797}
 798
 799/*
 800 * '--color-words' algorithm can be described as:
 801 *
 802 *   1. collect a the minus/plus lines of a diff hunk, divided into
 803 *      minus-lines and plus-lines;
 804 *
 805 *   2. break both minus-lines and plus-lines into words and
 806 *      place them into two mmfile_t with one word for each line;
 807 *
 808 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 809 *
 810 * And for the common parts of the both file, we output the plus side text.
 811 * diff_words->current_plus is used to trace the current position of the plus file
 812 * which printed. diff_words->last_minus is used to trace the last minus word
 813 * printed.
 814 *
 815 * For '--graph' to work with '--color-words', we need to output the graph prefix
 816 * on each line of color words output. Generally, there are two conditions on
 817 * which we should output the prefix.
 818 *
 819 *   1. diff_words->last_minus == 0 &&
 820 *      diff_words->current_plus == diff_words->plus.text.ptr
 821 *
 822 *      that is: the plus text must start as a new line, and if there is no minus
 823 *      word printed, a graph prefix must be printed.
 824 *
 825 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 826 *      *(diff_words->current_plus - 1) == '\n'
 827 *
 828 *      that is: a graph prefix must be printed following a '\n'
 829 */
 830static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 831{
 832        if ((diff_words->last_minus == 0 &&
 833                diff_words->current_plus == diff_words->plus.text.ptr) ||
 834                (diff_words->current_plus > diff_words->plus.text.ptr &&
 835                *(diff_words->current_plus - 1) == '\n')) {
 836                return 1;
 837        } else {
 838                return 0;
 839        }
 840}
 841
 842static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 843{
 844        struct diff_words_data *diff_words = priv;
 845        struct diff_words_style *style = diff_words->style;
 846        int minus_first, minus_len, plus_first, plus_len;
 847        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 848        struct diff_options *opt = diff_words->opt;
 849        const char *line_prefix;
 850
 851        if (line[0] != '@' || parse_hunk_header(line, len,
 852                        &minus_first, &minus_len, &plus_first, &plus_len))
 853                return;
 854
 855        assert(opt);
 856        line_prefix = diff_line_prefix(opt);
 857
 858        /* POSIX requires that first be decremented by one if len == 0... */
 859        if (minus_len) {
 860                minus_begin = diff_words->minus.orig[minus_first].begin;
 861                minus_end =
 862                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 863        } else
 864                minus_begin = minus_end =
 865                        diff_words->minus.orig[minus_first].end;
 866
 867        if (plus_len) {
 868                plus_begin = diff_words->plus.orig[plus_first].begin;
 869                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 870        } else
 871                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 872
 873        if (color_words_output_graph_prefix(diff_words)) {
 874                fputs(line_prefix, diff_words->opt->file);
 875        }
 876        if (diff_words->current_plus != plus_begin) {
 877                fn_out_diff_words_write_helper(diff_words->opt->file,
 878                                &style->ctx, style->newline,
 879                                plus_begin - diff_words->current_plus,
 880                                diff_words->current_plus, line_prefix);
 881                if (*(plus_begin - 1) == '\n')
 882                        fputs(line_prefix, diff_words->opt->file);
 883        }
 884        if (minus_begin != minus_end) {
 885                fn_out_diff_words_write_helper(diff_words->opt->file,
 886                                &style->old, style->newline,
 887                                minus_end - minus_begin, minus_begin,
 888                                line_prefix);
 889        }
 890        if (plus_begin != plus_end) {
 891                fn_out_diff_words_write_helper(diff_words->opt->file,
 892                                &style->new, style->newline,
 893                                plus_end - plus_begin, plus_begin,
 894                                line_prefix);
 895        }
 896
 897        diff_words->current_plus = plus_end;
 898        diff_words->last_minus = minus_first;
 899}
 900
 901/* This function starts looking at *begin, and returns 0 iff a word was found. */
 902static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 903                int *begin, int *end)
 904{
 905        if (word_regex && *begin < buffer->size) {
 906                regmatch_t match[1];
 907                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 908                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 909                                        '\n', match[0].rm_eo - match[0].rm_so);
 910                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 911                        *begin += match[0].rm_so;
 912                        return *begin >= *end;
 913                }
 914                return -1;
 915        }
 916
 917        /* find the next word */
 918        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 919                (*begin)++;
 920        if (*begin >= buffer->size)
 921                return -1;
 922
 923        /* find the end of the word */
 924        *end = *begin + 1;
 925        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 926                (*end)++;
 927
 928        return 0;
 929}
 930
 931/*
 932 * This function splits the words in buffer->text, stores the list with
 933 * newline separator into out, and saves the offsets of the original words
 934 * in buffer->orig.
 935 */
 936static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 937                regex_t *word_regex)
 938{
 939        int i, j;
 940        long alloc = 0;
 941
 942        out->size = 0;
 943        out->ptr = NULL;
 944
 945        /* fake an empty "0th" word */
 946        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 947        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 948        buffer->orig_nr = 1;
 949
 950        for (i = 0; i < buffer->text.size; i++) {
 951                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 952                        return;
 953
 954                /* store original boundaries */
 955                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 956                                buffer->orig_alloc);
 957                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 958                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 959                buffer->orig_nr++;
 960
 961                /* store one word */
 962                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 963                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 964                out->ptr[out->size + j - i] = '\n';
 965                out->size += j - i + 1;
 966
 967                i = j - 1;
 968        }
 969}
 970
 971/* this executes the word diff on the accumulated buffers */
 972static void diff_words_show(struct diff_words_data *diff_words)
 973{
 974        xpparam_t xpp;
 975        xdemitconf_t xecfg;
 976        mmfile_t minus, plus;
 977        struct diff_words_style *style = diff_words->style;
 978
 979        struct diff_options *opt = diff_words->opt;
 980        const char *line_prefix;
 981
 982        assert(opt);
 983        line_prefix = diff_line_prefix(opt);
 984
 985        /* special case: only removal */
 986        if (!diff_words->plus.text.size) {
 987                fputs(line_prefix, diff_words->opt->file);
 988                fn_out_diff_words_write_helper(diff_words->opt->file,
 989                        &style->old, style->newline,
 990                        diff_words->minus.text.size,
 991                        diff_words->minus.text.ptr, line_prefix);
 992                diff_words->minus.text.size = 0;
 993                return;
 994        }
 995
 996        diff_words->current_plus = diff_words->plus.text.ptr;
 997        diff_words->last_minus = 0;
 998
 999        memset(&xpp, 0, sizeof(xpp));
1000        memset(&xecfg, 0, sizeof(xecfg));
1001        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1002        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1003        xpp.flags = 0;
1004        /* as only the hunk header will be parsed, we need a 0-context */
1005        xecfg.ctxlen = 0;
1006        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1007                      &xpp, &xecfg);
1008        free(minus.ptr);
1009        free(plus.ptr);
1010        if (diff_words->current_plus != diff_words->plus.text.ptr +
1011                        diff_words->plus.text.size) {
1012                if (color_words_output_graph_prefix(diff_words))
1013                        fputs(line_prefix, diff_words->opt->file);
1014                fn_out_diff_words_write_helper(diff_words->opt->file,
1015                        &style->ctx, style->newline,
1016                        diff_words->plus.text.ptr + diff_words->plus.text.size
1017                        - diff_words->current_plus, diff_words->current_plus,
1018                        line_prefix);
1019        }
1020        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1021}
1022
1023/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1024static void diff_words_flush(struct emit_callback *ecbdata)
1025{
1026        if (ecbdata->diff_words->minus.text.size ||
1027            ecbdata->diff_words->plus.text.size)
1028                diff_words_show(ecbdata->diff_words);
1029}
1030
1031static void diff_filespec_load_driver(struct diff_filespec *one)
1032{
1033        /* Use already-loaded driver */
1034        if (one->driver)
1035                return;
1036
1037        if (S_ISREG(one->mode))
1038                one->driver = userdiff_find_by_path(one->path);
1039
1040        /* Fallback to default settings */
1041        if (!one->driver)
1042                one->driver = userdiff_find_by_name("default");
1043}
1044
1045static const char *userdiff_word_regex(struct diff_filespec *one)
1046{
1047        diff_filespec_load_driver(one);
1048        return one->driver->word_regex;
1049}
1050
1051static void init_diff_words_data(struct emit_callback *ecbdata,
1052                                 struct diff_options *orig_opts,
1053                                 struct diff_filespec *one,
1054                                 struct diff_filespec *two)
1055{
1056        int i;
1057        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1058        memcpy(o, orig_opts, sizeof(struct diff_options));
1059
1060        ecbdata->diff_words =
1061                xcalloc(1, sizeof(struct diff_words_data));
1062        ecbdata->diff_words->type = o->word_diff;
1063        ecbdata->diff_words->opt = o;
1064        if (!o->word_regex)
1065                o->word_regex = userdiff_word_regex(one);
1066        if (!o->word_regex)
1067                o->word_regex = userdiff_word_regex(two);
1068        if (!o->word_regex)
1069                o->word_regex = diff_word_regex_cfg;
1070        if (o->word_regex) {
1071                ecbdata->diff_words->word_regex = (regex_t *)
1072                        xmalloc(sizeof(regex_t));
1073                if (regcomp(ecbdata->diff_words->word_regex,
1074                            o->word_regex,
1075                            REG_EXTENDED | REG_NEWLINE))
1076                        die ("Invalid regular expression: %s",
1077                             o->word_regex);
1078        }
1079        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1080                if (o->word_diff == diff_words_styles[i].type) {
1081                        ecbdata->diff_words->style =
1082                                &diff_words_styles[i];
1083                        break;
1084                }
1085        }
1086        if (want_color(o->use_color)) {
1087                struct diff_words_style *st = ecbdata->diff_words->style;
1088                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1089                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1090                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1091        }
1092}
1093
1094static void free_diff_words_data(struct emit_callback *ecbdata)
1095{
1096        if (ecbdata->diff_words) {
1097                diff_words_flush(ecbdata);
1098                free (ecbdata->diff_words->opt);
1099                free (ecbdata->diff_words->minus.text.ptr);
1100                free (ecbdata->diff_words->minus.orig);
1101                free (ecbdata->diff_words->plus.text.ptr);
1102                free (ecbdata->diff_words->plus.orig);
1103                if (ecbdata->diff_words->word_regex) {
1104                        regfree(ecbdata->diff_words->word_regex);
1105                        free(ecbdata->diff_words->word_regex);
1106                }
1107                free(ecbdata->diff_words);
1108                ecbdata->diff_words = NULL;
1109        }
1110}
1111
1112const char *diff_get_color(int diff_use_color, enum color_diff ix)
1113{
1114        if (want_color(diff_use_color))
1115                return diff_colors[ix];
1116        return "";
1117}
1118
1119const char *diff_line_prefix(struct diff_options *opt)
1120{
1121        struct strbuf *msgbuf;
1122        if (!opt->output_prefix)
1123                return "";
1124
1125        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1126        return msgbuf->buf;
1127}
1128
1129static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1130{
1131        const char *cp;
1132        unsigned long allot;
1133        size_t l = len;
1134
1135        if (ecb->truncate)
1136                return ecb->truncate(line, len);
1137        cp = line;
1138        allot = l;
1139        while (0 < l) {
1140                (void) utf8_width(&cp, &l);
1141                if (!cp)
1142                        break; /* truncated in the middle? */
1143        }
1144        return allot - l;
1145}
1146
1147static void find_lno(const char *line, struct emit_callback *ecbdata)
1148{
1149        const char *p;
1150        ecbdata->lno_in_preimage = 0;
1151        ecbdata->lno_in_postimage = 0;
1152        p = strchr(line, '-');
1153        if (!p)
1154                return; /* cannot happen */
1155        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1156        p = strchr(p, '+');
1157        if (!p)
1158                return; /* cannot happen */
1159        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1160}
1161
1162static void fn_out_consume(void *priv, char *line, unsigned long len)
1163{
1164        struct emit_callback *ecbdata = priv;
1165        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1166        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1167        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1168        struct diff_options *o = ecbdata->opt;
1169        const char *line_prefix = diff_line_prefix(o);
1170
1171        if (ecbdata->header) {
1172                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1173                strbuf_reset(ecbdata->header);
1174                ecbdata->header = NULL;
1175        }
1176        *(ecbdata->found_changesp) = 1;
1177
1178        if (ecbdata->label_path[0]) {
1179                const char *name_a_tab, *name_b_tab;
1180
1181                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1182                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1183
1184                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1185                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1186                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1187                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1188                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1189        }
1190
1191        if (diff_suppress_blank_empty
1192            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1193                line[0] = '\n';
1194                len = 1;
1195        }
1196
1197        if (line[0] == '@') {
1198                if (ecbdata->diff_words)
1199                        diff_words_flush(ecbdata);
1200                len = sane_truncate_line(ecbdata, line, len);
1201                find_lno(line, ecbdata);
1202                emit_hunk_header(ecbdata, line, len);
1203                if (line[len-1] != '\n')
1204                        putc('\n', ecbdata->opt->file);
1205                return;
1206        }
1207
1208        if (len < 1) {
1209                emit_line(ecbdata->opt, reset, reset, line, len);
1210                if (ecbdata->diff_words
1211                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1212                        fputs("~\n", ecbdata->opt->file);
1213                return;
1214        }
1215
1216        if (ecbdata->diff_words) {
1217                if (line[0] == '-') {
1218                        diff_words_append(line, len,
1219                                          &ecbdata->diff_words->minus);
1220                        return;
1221                } else if (line[0] == '+') {
1222                        diff_words_append(line, len,
1223                                          &ecbdata->diff_words->plus);
1224                        return;
1225                } else if (starts_with(line, "\\ ")) {
1226                        /*
1227                         * Eat the "no newline at eof" marker as if we
1228                         * saw a "+" or "-" line with nothing on it,
1229                         * and return without diff_words_flush() to
1230                         * defer processing. If this is the end of
1231                         * preimage, more "+" lines may come after it.
1232                         */
1233                        return;
1234                }
1235                diff_words_flush(ecbdata);
1236                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1237                        emit_line(ecbdata->opt, plain, reset, line, len);
1238                        fputs("~\n", ecbdata->opt->file);
1239                } else {
1240                        /*
1241                         * Skip the prefix character, if any.  With
1242                         * diff_suppress_blank_empty, there may be
1243                         * none.
1244                         */
1245                        if (line[0] != '\n') {
1246                              line++;
1247                              len--;
1248                        }
1249                        emit_line(ecbdata->opt, plain, reset, line, len);
1250                }
1251                return;
1252        }
1253
1254        if (line[0] != '+') {
1255                const char *color =
1256                        diff_get_color(ecbdata->color_diff,
1257                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1258                ecbdata->lno_in_preimage++;
1259                if (line[0] == ' ')
1260                        ecbdata->lno_in_postimage++;
1261                emit_line(ecbdata->opt, color, reset, line, len);
1262        } else {
1263                ecbdata->lno_in_postimage++;
1264                emit_add_line(reset, ecbdata, line + 1, len - 1);
1265        }
1266}
1267
1268static char *pprint_rename(const char *a, const char *b)
1269{
1270        const char *old = a;
1271        const char *new = b;
1272        struct strbuf name = STRBUF_INIT;
1273        int pfx_length, sfx_length;
1274        int pfx_adjust_for_slash;
1275        int len_a = strlen(a);
1276        int len_b = strlen(b);
1277        int a_midlen, b_midlen;
1278        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1279        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1280
1281        if (qlen_a || qlen_b) {
1282                quote_c_style(a, &name, NULL, 0);
1283                strbuf_addstr(&name, " => ");
1284                quote_c_style(b, &name, NULL, 0);
1285                return strbuf_detach(&name, NULL);
1286        }
1287
1288        /* Find common prefix */
1289        pfx_length = 0;
1290        while (*old && *new && *old == *new) {
1291                if (*old == '/')
1292                        pfx_length = old - a + 1;
1293                old++;
1294                new++;
1295        }
1296
1297        /* Find common suffix */
1298        old = a + len_a;
1299        new = b + len_b;
1300        sfx_length = 0;
1301        /*
1302         * If there is a common prefix, it must end in a slash.  In
1303         * that case we let this loop run 1 into the prefix to see the
1304         * same slash.
1305         *
1306         * If there is no common prefix, we cannot do this as it would
1307         * underrun the input strings.
1308         */
1309        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1310        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1311               b + pfx_length - pfx_adjust_for_slash <= new &&
1312               *old == *new) {
1313                if (*old == '/')
1314                        sfx_length = len_a - (old - a);
1315                old--;
1316                new--;
1317        }
1318
1319        /*
1320         * pfx{mid-a => mid-b}sfx
1321         * {pfx-a => pfx-b}sfx
1322         * pfx{sfx-a => sfx-b}
1323         * name-a => name-b
1324         */
1325        a_midlen = len_a - pfx_length - sfx_length;
1326        b_midlen = len_b - pfx_length - sfx_length;
1327        if (a_midlen < 0)
1328                a_midlen = 0;
1329        if (b_midlen < 0)
1330                b_midlen = 0;
1331
1332        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1333        if (pfx_length + sfx_length) {
1334                strbuf_add(&name, a, pfx_length);
1335                strbuf_addch(&name, '{');
1336        }
1337        strbuf_add(&name, a + pfx_length, a_midlen);
1338        strbuf_addstr(&name, " => ");
1339        strbuf_add(&name, b + pfx_length, b_midlen);
1340        if (pfx_length + sfx_length) {
1341                strbuf_addch(&name, '}');
1342                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1343        }
1344        return strbuf_detach(&name, NULL);
1345}
1346
1347struct diffstat_t {
1348        int nr;
1349        int alloc;
1350        struct diffstat_file {
1351                char *from_name;
1352                char *name;
1353                char *print_name;
1354                unsigned is_unmerged:1;
1355                unsigned is_binary:1;
1356                unsigned is_renamed:1;
1357                unsigned is_interesting:1;
1358                uintmax_t added, deleted;
1359        } **files;
1360};
1361
1362static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1363                                          const char *name_a,
1364                                          const char *name_b)
1365{
1366        struct diffstat_file *x;
1367        x = xcalloc(1, sizeof(*x));
1368        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1369        diffstat->files[diffstat->nr++] = x;
1370        if (name_b) {
1371                x->from_name = xstrdup(name_a);
1372                x->name = xstrdup(name_b);
1373                x->is_renamed = 1;
1374        }
1375        else {
1376                x->from_name = NULL;
1377                x->name = xstrdup(name_a);
1378        }
1379        return x;
1380}
1381
1382static void diffstat_consume(void *priv, char *line, unsigned long len)
1383{
1384        struct diffstat_t *diffstat = priv;
1385        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1386
1387        if (line[0] == '+')
1388                x->added++;
1389        else if (line[0] == '-')
1390                x->deleted++;
1391}
1392
1393const char mime_boundary_leader[] = "------------";
1394
1395static int scale_linear(int it, int width, int max_change)
1396{
1397        if (!it)
1398                return 0;
1399        /*
1400         * make sure that at least one '-' or '+' is printed if
1401         * there is any change to this path. The easiest way is to
1402         * scale linearly as if the alloted width is one column shorter
1403         * than it is, and then add 1 to the result.
1404         */
1405        return 1 + (it * (width - 1) / max_change);
1406}
1407
1408static void show_name(FILE *file,
1409                      const char *prefix, const char *name, int len)
1410{
1411        fprintf(file, " %s%-*s |", prefix, len, name);
1412}
1413
1414static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1415{
1416        if (cnt <= 0)
1417                return;
1418        fprintf(file, "%s", set);
1419        while (cnt--)
1420                putc(ch, file);
1421        fprintf(file, "%s", reset);
1422}
1423
1424static void fill_print_name(struct diffstat_file *file)
1425{
1426        char *pname;
1427
1428        if (file->print_name)
1429                return;
1430
1431        if (!file->is_renamed) {
1432                struct strbuf buf = STRBUF_INIT;
1433                if (quote_c_style(file->name, &buf, NULL, 0)) {
1434                        pname = strbuf_detach(&buf, NULL);
1435                } else {
1436                        pname = file->name;
1437                        strbuf_release(&buf);
1438                }
1439        } else {
1440                pname = pprint_rename(file->from_name, file->name);
1441        }
1442        file->print_name = pname;
1443}
1444
1445int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1446{
1447        struct strbuf sb = STRBUF_INIT;
1448        int ret;
1449
1450        if (!files) {
1451                assert(insertions == 0 && deletions == 0);
1452                return fprintf(fp, "%s\n", " 0 files changed");
1453        }
1454
1455        strbuf_addf(&sb,
1456                    (files == 1) ? " %d file changed" : " %d files changed",
1457                    files);
1458
1459        /*
1460         * For binary diff, the caller may want to print "x files
1461         * changed" with insertions == 0 && deletions == 0.
1462         *
1463         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1464         * is probably less confusing (i.e skip over "2 files changed
1465         * but nothing about added/removed lines? Is this a bug in Git?").
1466         */
1467        if (insertions || deletions == 0) {
1468                strbuf_addf(&sb,
1469                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1470                            insertions);
1471        }
1472
1473        if (deletions || insertions == 0) {
1474                strbuf_addf(&sb,
1475                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1476                            deletions);
1477        }
1478        strbuf_addch(&sb, '\n');
1479        ret = fputs(sb.buf, fp);
1480        strbuf_release(&sb);
1481        return ret;
1482}
1483
1484static void show_stats(struct diffstat_t *data, struct diff_options *options)
1485{
1486        int i, len, add, del, adds = 0, dels = 0;
1487        uintmax_t max_change = 0, max_len = 0;
1488        int total_files = data->nr, count;
1489        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1490        const char *reset, *add_c, *del_c;
1491        const char *line_prefix = "";
1492        int extra_shown = 0;
1493
1494        if (data->nr == 0)
1495                return;
1496
1497        line_prefix = diff_line_prefix(options);
1498        count = options->stat_count ? options->stat_count : data->nr;
1499
1500        reset = diff_get_color_opt(options, DIFF_RESET);
1501        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1502        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1503
1504        /*
1505         * Find the longest filename and max number of changes
1506         */
1507        for (i = 0; (i < count) && (i < data->nr); i++) {
1508                struct diffstat_file *file = data->files[i];
1509                uintmax_t change = file->added + file->deleted;
1510
1511                if (!file->is_interesting && (change == 0)) {
1512                        count++; /* not shown == room for one more */
1513                        continue;
1514                }
1515                fill_print_name(file);
1516                len = strlen(file->print_name);
1517                if (max_len < len)
1518                        max_len = len;
1519
1520                if (file->is_unmerged) {
1521                        /* "Unmerged" is 8 characters */
1522                        bin_width = bin_width < 8 ? 8 : bin_width;
1523                        continue;
1524                }
1525                if (file->is_binary) {
1526                        /* "Bin XXX -> YYY bytes" */
1527                        int w = 14 + decimal_width(file->added)
1528                                + decimal_width(file->deleted);
1529                        bin_width = bin_width < w ? w : bin_width;
1530                        /* Display change counts aligned with "Bin" */
1531                        number_width = 3;
1532                        continue;
1533                }
1534
1535                if (max_change < change)
1536                        max_change = change;
1537        }
1538        count = i; /* where we can stop scanning in data->files[] */
1539
1540        /*
1541         * We have width = stat_width or term_columns() columns total.
1542         * We want a maximum of min(max_len, stat_name_width) for the name part.
1543         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1544         * We also need 1 for " " and 4 + decimal_width(max_change)
1545         * for " | NNNN " and one the empty column at the end, altogether
1546         * 6 + decimal_width(max_change).
1547         *
1548         * If there's not enough space, we will use the smaller of
1549         * stat_name_width (if set) and 5/8*width for the filename,
1550         * and the rest for constant elements + graph part, but no more
1551         * than stat_graph_width for the graph part.
1552         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1553         * for the standard terminal size).
1554         *
1555         * In other words: stat_width limits the maximum width, and
1556         * stat_name_width fixes the maximum width of the filename,
1557         * and is also used to divide available columns if there
1558         * aren't enough.
1559         *
1560         * Binary files are displayed with "Bin XXX -> YYY bytes"
1561         * instead of the change count and graph. This part is treated
1562         * similarly to the graph part, except that it is not
1563         * "scaled". If total width is too small to accommodate the
1564         * guaranteed minimum width of the filename part and the
1565         * separators and this message, this message will "overflow"
1566         * making the line longer than the maximum width.
1567         */
1568
1569        if (options->stat_width == -1)
1570                width = term_columns() - options->output_prefix_length;
1571        else
1572                width = options->stat_width ? options->stat_width : 80;
1573        number_width = decimal_width(max_change) > number_width ?
1574                decimal_width(max_change) : number_width;
1575
1576        if (options->stat_graph_width == -1)
1577                options->stat_graph_width = diff_stat_graph_width;
1578
1579        /*
1580         * Guarantee 3/8*16==6 for the graph part
1581         * and 5/8*16==10 for the filename part
1582         */
1583        if (width < 16 + 6 + number_width)
1584                width = 16 + 6 + number_width;
1585
1586        /*
1587         * First assign sizes that are wanted, ignoring available width.
1588         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1589         * starting from "XXX" should fit in graph_width.
1590         */
1591        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1592        if (options->stat_graph_width &&
1593            options->stat_graph_width < graph_width)
1594                graph_width = options->stat_graph_width;
1595
1596        name_width = (options->stat_name_width > 0 &&
1597                      options->stat_name_width < max_len) ?
1598                options->stat_name_width : max_len;
1599
1600        /*
1601         * Adjust adjustable widths not to exceed maximum width
1602         */
1603        if (name_width + number_width + 6 + graph_width > width) {
1604                if (graph_width > width * 3/8 - number_width - 6) {
1605                        graph_width = width * 3/8 - number_width - 6;
1606                        if (graph_width < 6)
1607                                graph_width = 6;
1608                }
1609
1610                if (options->stat_graph_width &&
1611                    graph_width > options->stat_graph_width)
1612                        graph_width = options->stat_graph_width;
1613                if (name_width > width - number_width - 6 - graph_width)
1614                        name_width = width - number_width - 6 - graph_width;
1615                else
1616                        graph_width = width - number_width - 6 - name_width;
1617        }
1618
1619        /*
1620         * From here name_width is the width of the name area,
1621         * and graph_width is the width of the graph area.
1622         * max_change is used to scale graph properly.
1623         */
1624        for (i = 0; i < count; i++) {
1625                const char *prefix = "";
1626                struct diffstat_file *file = data->files[i];
1627                char *name = file->print_name;
1628                uintmax_t added = file->added;
1629                uintmax_t deleted = file->deleted;
1630                int name_len;
1631
1632                if (!file->is_interesting && (added + deleted == 0))
1633                        continue;
1634
1635                /*
1636                 * "scale" the filename
1637                 */
1638                len = name_width;
1639                name_len = strlen(name);
1640                if (name_width < name_len) {
1641                        char *slash;
1642                        prefix = "...";
1643                        len -= 3;
1644                        name += name_len - len;
1645                        slash = strchr(name, '/');
1646                        if (slash)
1647                                name = slash;
1648                }
1649
1650                if (file->is_binary) {
1651                        fprintf(options->file, "%s", line_prefix);
1652                        show_name(options->file, prefix, name, len);
1653                        fprintf(options->file, " %*s", number_width, "Bin");
1654                        if (!added && !deleted) {
1655                                putc('\n', options->file);
1656                                continue;
1657                        }
1658                        fprintf(options->file, " %s%"PRIuMAX"%s",
1659                                del_c, deleted, reset);
1660                        fprintf(options->file, " -> ");
1661                        fprintf(options->file, "%s%"PRIuMAX"%s",
1662                                add_c, added, reset);
1663                        fprintf(options->file, " bytes");
1664                        fprintf(options->file, "\n");
1665                        continue;
1666                }
1667                else if (file->is_unmerged) {
1668                        fprintf(options->file, "%s", line_prefix);
1669                        show_name(options->file, prefix, name, len);
1670                        fprintf(options->file, " Unmerged\n");
1671                        continue;
1672                }
1673
1674                /*
1675                 * scale the add/delete
1676                 */
1677                add = added;
1678                del = deleted;
1679
1680                if (graph_width <= max_change) {
1681                        int total = scale_linear(add + del, graph_width, max_change);
1682                        if (total < 2 && add && del)
1683                                /* width >= 2 due to the sanity check */
1684                                total = 2;
1685                        if (add < del) {
1686                                add = scale_linear(add, graph_width, max_change);
1687                                del = total - add;
1688                        } else {
1689                                del = scale_linear(del, graph_width, max_change);
1690                                add = total - del;
1691                        }
1692                }
1693                fprintf(options->file, "%s", line_prefix);
1694                show_name(options->file, prefix, name, len);
1695                fprintf(options->file, " %*"PRIuMAX"%s",
1696                        number_width, added + deleted,
1697                        added + deleted ? " " : "");
1698                show_graph(options->file, '+', add, add_c, reset);
1699                show_graph(options->file, '-', del, del_c, reset);
1700                fprintf(options->file, "\n");
1701        }
1702
1703        for (i = 0; i < data->nr; i++) {
1704                struct diffstat_file *file = data->files[i];
1705                uintmax_t added = file->added;
1706                uintmax_t deleted = file->deleted;
1707
1708                if (file->is_unmerged ||
1709                    (!file->is_interesting && (added + deleted == 0))) {
1710                        total_files--;
1711                        continue;
1712                }
1713
1714                if (!file->is_binary) {
1715                        adds += added;
1716                        dels += deleted;
1717                }
1718                if (i < count)
1719                        continue;
1720                if (!extra_shown)
1721                        fprintf(options->file, "%s ...\n", line_prefix);
1722                extra_shown = 1;
1723        }
1724        fprintf(options->file, "%s", line_prefix);
1725        print_stat_summary(options->file, total_files, adds, dels);
1726}
1727
1728static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1729{
1730        int i, adds = 0, dels = 0, total_files = data->nr;
1731
1732        if (data->nr == 0)
1733                return;
1734
1735        for (i = 0; i < data->nr; i++) {
1736                int added = data->files[i]->added;
1737                int deleted= data->files[i]->deleted;
1738
1739                if (data->files[i]->is_unmerged ||
1740                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1741                        total_files--;
1742                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1743                        adds += added;
1744                        dels += deleted;
1745                }
1746        }
1747        fprintf(options->file, "%s", diff_line_prefix(options));
1748        print_stat_summary(options->file, total_files, adds, dels);
1749}
1750
1751static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1752{
1753        int i;
1754
1755        if (data->nr == 0)
1756                return;
1757
1758        for (i = 0; i < data->nr; i++) {
1759                struct diffstat_file *file = data->files[i];
1760
1761                fprintf(options->file, "%s", diff_line_prefix(options));
1762
1763                if (file->is_binary)
1764                        fprintf(options->file, "-\t-\t");
1765                else
1766                        fprintf(options->file,
1767                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1768                                file->added, file->deleted);
1769                if (options->line_termination) {
1770                        fill_print_name(file);
1771                        if (!file->is_renamed)
1772                                write_name_quoted(file->name, options->file,
1773                                                  options->line_termination);
1774                        else {
1775                                fputs(file->print_name, options->file);
1776                                putc(options->line_termination, options->file);
1777                        }
1778                } else {
1779                        if (file->is_renamed) {
1780                                putc('\0', options->file);
1781                                write_name_quoted(file->from_name, options->file, '\0');
1782                        }
1783                        write_name_quoted(file->name, options->file, '\0');
1784                }
1785        }
1786}
1787
1788struct dirstat_file {
1789        const char *name;
1790        unsigned long changed;
1791};
1792
1793struct dirstat_dir {
1794        struct dirstat_file *files;
1795        int alloc, nr, permille, cumulative;
1796};
1797
1798static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1799                unsigned long changed, const char *base, int baselen)
1800{
1801        unsigned long this_dir = 0;
1802        unsigned int sources = 0;
1803        const char *line_prefix = diff_line_prefix(opt);
1804
1805        while (dir->nr) {
1806                struct dirstat_file *f = dir->files;
1807                int namelen = strlen(f->name);
1808                unsigned long this;
1809                char *slash;
1810
1811                if (namelen < baselen)
1812                        break;
1813                if (memcmp(f->name, base, baselen))
1814                        break;
1815                slash = strchr(f->name + baselen, '/');
1816                if (slash) {
1817                        int newbaselen = slash + 1 - f->name;
1818                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1819                        sources++;
1820                } else {
1821                        this = f->changed;
1822                        dir->files++;
1823                        dir->nr--;
1824                        sources += 2;
1825                }
1826                this_dir += this;
1827        }
1828
1829        /*
1830         * We don't report dirstat's for
1831         *  - the top level
1832         *  - or cases where everything came from a single directory
1833         *    under this directory (sources == 1).
1834         */
1835        if (baselen && sources != 1) {
1836                if (this_dir) {
1837                        int permille = this_dir * 1000 / changed;
1838                        if (permille >= dir->permille) {
1839                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1840                                        permille / 10, permille % 10, baselen, base);
1841                                if (!dir->cumulative)
1842                                        return 0;
1843                        }
1844                }
1845        }
1846        return this_dir;
1847}
1848
1849static int dirstat_compare(const void *_a, const void *_b)
1850{
1851        const struct dirstat_file *a = _a;
1852        const struct dirstat_file *b = _b;
1853        return strcmp(a->name, b->name);
1854}
1855
1856static void show_dirstat(struct diff_options *options)
1857{
1858        int i;
1859        unsigned long changed;
1860        struct dirstat_dir dir;
1861        struct diff_queue_struct *q = &diff_queued_diff;
1862
1863        dir.files = NULL;
1864        dir.alloc = 0;
1865        dir.nr = 0;
1866        dir.permille = options->dirstat_permille;
1867        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1868
1869        changed = 0;
1870        for (i = 0; i < q->nr; i++) {
1871                struct diff_filepair *p = q->queue[i];
1872                const char *name;
1873                unsigned long copied, added, damage;
1874                int content_changed;
1875
1876                name = p->two->path ? p->two->path : p->one->path;
1877
1878                if (p->one->sha1_valid && p->two->sha1_valid)
1879                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1880                else
1881                        content_changed = 1;
1882
1883                if (!content_changed) {
1884                        /*
1885                         * The SHA1 has not changed, so pre-/post-content is
1886                         * identical. We can therefore skip looking at the
1887                         * file contents altogether.
1888                         */
1889                        damage = 0;
1890                        goto found_damage;
1891                }
1892
1893                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1894                        /*
1895                         * In --dirstat-by-file mode, we don't really need to
1896                         * look at the actual file contents at all.
1897                         * The fact that the SHA1 changed is enough for us to
1898                         * add this file to the list of results
1899                         * (with each file contributing equal damage).
1900                         */
1901                        damage = 1;
1902                        goto found_damage;
1903                }
1904
1905                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1906                        diff_populate_filespec(p->one, 0);
1907                        diff_populate_filespec(p->two, 0);
1908                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1909                                               &copied, &added);
1910                        diff_free_filespec_data(p->one);
1911                        diff_free_filespec_data(p->two);
1912                } else if (DIFF_FILE_VALID(p->one)) {
1913                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1914                        copied = added = 0;
1915                        diff_free_filespec_data(p->one);
1916                } else if (DIFF_FILE_VALID(p->two)) {
1917                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1918                        copied = 0;
1919                        added = p->two->size;
1920                        diff_free_filespec_data(p->two);
1921                } else
1922                        continue;
1923
1924                /*
1925                 * Original minus copied is the removed material,
1926                 * added is the new material.  They are both damages
1927                 * made to the preimage.
1928                 * If the resulting damage is zero, we know that
1929                 * diffcore_count_changes() considers the two entries to
1930                 * be identical, but since content_changed is true, we
1931                 * know that there must have been _some_ kind of change,
1932                 * so we force all entries to have damage > 0.
1933                 */
1934                damage = (p->one->size - copied) + added;
1935                if (!damage)
1936                        damage = 1;
1937
1938found_damage:
1939                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1940                dir.files[dir.nr].name = name;
1941                dir.files[dir.nr].changed = damage;
1942                changed += damage;
1943                dir.nr++;
1944        }
1945
1946        /* This can happen even with many files, if everything was renames */
1947        if (!changed)
1948                return;
1949
1950        /* Show all directories with more than x% of the changes */
1951        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1952        gather_dirstat(options, &dir, changed, "", 0);
1953}
1954
1955static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1956{
1957        int i;
1958        unsigned long changed;
1959        struct dirstat_dir dir;
1960
1961        if (data->nr == 0)
1962                return;
1963
1964        dir.files = NULL;
1965        dir.alloc = 0;
1966        dir.nr = 0;
1967        dir.permille = options->dirstat_permille;
1968        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1969
1970        changed = 0;
1971        for (i = 0; i < data->nr; i++) {
1972                struct diffstat_file *file = data->files[i];
1973                unsigned long damage = file->added + file->deleted;
1974                if (file->is_binary)
1975                        /*
1976                         * binary files counts bytes, not lines. Must find some
1977                         * way to normalize binary bytes vs. textual lines.
1978                         * The following heuristic assumes that there are 64
1979                         * bytes per "line".
1980                         * This is stupid and ugly, but very cheap...
1981                         */
1982                        damage = (damage + 63) / 64;
1983                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1984                dir.files[dir.nr].name = file->name;
1985                dir.files[dir.nr].changed = damage;
1986                changed += damage;
1987                dir.nr++;
1988        }
1989
1990        /* This can happen even with many files, if everything was renames */
1991        if (!changed)
1992                return;
1993
1994        /* Show all directories with more than x% of the changes */
1995        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1996        gather_dirstat(options, &dir, changed, "", 0);
1997}
1998
1999static void free_diffstat_info(struct diffstat_t *diffstat)
2000{
2001        int i;
2002        for (i = 0; i < diffstat->nr; i++) {
2003                struct diffstat_file *f = diffstat->files[i];
2004                if (f->name != f->print_name)
2005                        free(f->print_name);
2006                free(f->name);
2007                free(f->from_name);
2008                free(f);
2009        }
2010        free(diffstat->files);
2011}
2012
2013struct checkdiff_t {
2014        const char *filename;
2015        int lineno;
2016        int conflict_marker_size;
2017        struct diff_options *o;
2018        unsigned ws_rule;
2019        unsigned status;
2020};
2021
2022static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2023{
2024        char firstchar;
2025        int cnt;
2026
2027        if (len < marker_size + 1)
2028                return 0;
2029        firstchar = line[0];
2030        switch (firstchar) {
2031        case '=': case '>': case '<': case '|':
2032                break;
2033        default:
2034                return 0;
2035        }
2036        for (cnt = 1; cnt < marker_size; cnt++)
2037                if (line[cnt] != firstchar)
2038                        return 0;
2039        /* line[1] thru line[marker_size-1] are same as firstchar */
2040        if (len < marker_size + 1 || !isspace(line[marker_size]))
2041                return 0;
2042        return 1;
2043}
2044
2045static void checkdiff_consume(void *priv, char *line, unsigned long len)
2046{
2047        struct checkdiff_t *data = priv;
2048        int marker_size = data->conflict_marker_size;
2049        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2050        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2051        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2052        char *err;
2053        const char *line_prefix;
2054
2055        assert(data->o);
2056        line_prefix = diff_line_prefix(data->o);
2057
2058        if (line[0] == '+') {
2059                unsigned bad;
2060                data->lineno++;
2061                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2062                        data->status |= 1;
2063                        fprintf(data->o->file,
2064                                "%s%s:%d: leftover conflict marker\n",
2065                                line_prefix, data->filename, data->lineno);
2066                }
2067                bad = ws_check(line + 1, len - 1, data->ws_rule);
2068                if (!bad)
2069                        return;
2070                data->status |= bad;
2071                err = whitespace_error_string(bad);
2072                fprintf(data->o->file, "%s%s:%d: %s.\n",
2073                        line_prefix, data->filename, data->lineno, err);
2074                free(err);
2075                emit_line(data->o, set, reset, line, 1);
2076                ws_check_emit(line + 1, len - 1, data->ws_rule,
2077                              data->o->file, set, reset, ws);
2078        } else if (line[0] == ' ') {
2079                data->lineno++;
2080        } else if (line[0] == '@') {
2081                char *plus = strchr(line, '+');
2082                if (plus)
2083                        data->lineno = strtol(plus, NULL, 10) - 1;
2084                else
2085                        die("invalid diff");
2086        }
2087}
2088
2089static unsigned char *deflate_it(char *data,
2090                                 unsigned long size,
2091                                 unsigned long *result_size)
2092{
2093        int bound;
2094        unsigned char *deflated;
2095        git_zstream stream;
2096
2097        git_deflate_init(&stream, zlib_compression_level);
2098        bound = git_deflate_bound(&stream, size);
2099        deflated = xmalloc(bound);
2100        stream.next_out = deflated;
2101        stream.avail_out = bound;
2102
2103        stream.next_in = (unsigned char *)data;
2104        stream.avail_in = size;
2105        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2106                ; /* nothing */
2107        git_deflate_end(&stream);
2108        *result_size = stream.total_out;
2109        return deflated;
2110}
2111
2112static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2113                                  const char *prefix)
2114{
2115        void *cp;
2116        void *delta;
2117        void *deflated;
2118        void *data;
2119        unsigned long orig_size;
2120        unsigned long delta_size;
2121        unsigned long deflate_size;
2122        unsigned long data_size;
2123
2124        /* We could do deflated delta, or we could do just deflated two,
2125         * whichever is smaller.
2126         */
2127        delta = NULL;
2128        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2129        if (one->size && two->size) {
2130                delta = diff_delta(one->ptr, one->size,
2131                                   two->ptr, two->size,
2132                                   &delta_size, deflate_size);
2133                if (delta) {
2134                        void *to_free = delta;
2135                        orig_size = delta_size;
2136                        delta = deflate_it(delta, delta_size, &delta_size);
2137                        free(to_free);
2138                }
2139        }
2140
2141        if (delta && delta_size < deflate_size) {
2142                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2143                free(deflated);
2144                data = delta;
2145                data_size = delta_size;
2146        }
2147        else {
2148                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2149                free(delta);
2150                data = deflated;
2151                data_size = deflate_size;
2152        }
2153
2154        /* emit data encoded in base85 */
2155        cp = data;
2156        while (data_size) {
2157                int bytes = (52 < data_size) ? 52 : data_size;
2158                char line[70];
2159                data_size -= bytes;
2160                if (bytes <= 26)
2161                        line[0] = bytes + 'A' - 1;
2162                else
2163                        line[0] = bytes - 26 + 'a' - 1;
2164                encode_85(line + 1, cp, bytes);
2165                cp = (char *) cp + bytes;
2166                fprintf(file, "%s", prefix);
2167                fputs(line, file);
2168                fputc('\n', file);
2169        }
2170        fprintf(file, "%s\n", prefix);
2171        free(data);
2172}
2173
2174static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2175                             const char *prefix)
2176{
2177        fprintf(file, "%sGIT binary patch\n", prefix);
2178        emit_binary_diff_body(file, one, two, prefix);
2179        emit_binary_diff_body(file, two, one, prefix);
2180}
2181
2182int diff_filespec_is_binary(struct diff_filespec *one)
2183{
2184        if (one->is_binary == -1) {
2185                diff_filespec_load_driver(one);
2186                if (one->driver->binary != -1)
2187                        one->is_binary = one->driver->binary;
2188                else {
2189                        if (!one->data && DIFF_FILE_VALID(one))
2190                                diff_populate_filespec(one, CHECK_BINARY);
2191                        if (one->is_binary == -1 && one->data)
2192                                one->is_binary = buffer_is_binary(one->data,
2193                                                one->size);
2194                        if (one->is_binary == -1)
2195                                one->is_binary = 0;
2196                }
2197        }
2198        return one->is_binary;
2199}
2200
2201static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2202{
2203        diff_filespec_load_driver(one);
2204        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2205}
2206
2207void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2208{
2209        if (!options->a_prefix)
2210                options->a_prefix = a;
2211        if (!options->b_prefix)
2212                options->b_prefix = b;
2213}
2214
2215struct userdiff_driver *get_textconv(struct diff_filespec *one)
2216{
2217        if (!DIFF_FILE_VALID(one))
2218                return NULL;
2219
2220        diff_filespec_load_driver(one);
2221        return userdiff_get_textconv(one->driver);
2222}
2223
2224static void builtin_diff(const char *name_a,
2225                         const char *name_b,
2226                         struct diff_filespec *one,
2227                         struct diff_filespec *two,
2228                         const char *xfrm_msg,
2229                         int must_show_header,
2230                         struct diff_options *o,
2231                         int complete_rewrite)
2232{
2233        mmfile_t mf1, mf2;
2234        const char *lbl[2];
2235        char *a_one, *b_two;
2236        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2237        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2238        const char *a_prefix, *b_prefix;
2239        struct userdiff_driver *textconv_one = NULL;
2240        struct userdiff_driver *textconv_two = NULL;
2241        struct strbuf header = STRBUF_INIT;
2242        const char *line_prefix = diff_line_prefix(o);
2243
2244        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2245                        (!one->mode || S_ISGITLINK(one->mode)) &&
2246                        (!two->mode || S_ISGITLINK(two->mode))) {
2247                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2248                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2249                show_submodule_summary(o->file, one->path ? one->path : two->path,
2250                                line_prefix,
2251                                one->sha1, two->sha1, two->dirty_submodule,
2252                                meta, del, add, reset);
2253                return;
2254        }
2255
2256        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2257                textconv_one = get_textconv(one);
2258                textconv_two = get_textconv(two);
2259        }
2260
2261        diff_set_mnemonic_prefix(o, "a/", "b/");
2262        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2263                a_prefix = o->b_prefix;
2264                b_prefix = o->a_prefix;
2265        } else {
2266                a_prefix = o->a_prefix;
2267                b_prefix = o->b_prefix;
2268        }
2269
2270        /* Never use a non-valid filename anywhere if at all possible */
2271        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2272        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2273
2274        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2275        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2276        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2277        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2278        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2279        if (lbl[0][0] == '/') {
2280                /* /dev/null */
2281                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2282                if (xfrm_msg)
2283                        strbuf_addstr(&header, xfrm_msg);
2284                must_show_header = 1;
2285        }
2286        else if (lbl[1][0] == '/') {
2287                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2288                if (xfrm_msg)
2289                        strbuf_addstr(&header, xfrm_msg);
2290                must_show_header = 1;
2291        }
2292        else {
2293                if (one->mode != two->mode) {
2294                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2295                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2296                        must_show_header = 1;
2297                }
2298                if (xfrm_msg)
2299                        strbuf_addstr(&header, xfrm_msg);
2300
2301                /*
2302                 * we do not run diff between different kind
2303                 * of objects.
2304                 */
2305                if ((one->mode ^ two->mode) & S_IFMT)
2306                        goto free_ab_and_return;
2307                if (complete_rewrite &&
2308                    (textconv_one || !diff_filespec_is_binary(one)) &&
2309                    (textconv_two || !diff_filespec_is_binary(two))) {
2310                        fprintf(o->file, "%s", header.buf);
2311                        strbuf_reset(&header);
2312                        emit_rewrite_diff(name_a, name_b, one, two,
2313                                                textconv_one, textconv_two, o);
2314                        o->found_changes = 1;
2315                        goto free_ab_and_return;
2316                }
2317        }
2318
2319        if (o->irreversible_delete && lbl[1][0] == '/') {
2320                fprintf(o->file, "%s", header.buf);
2321                strbuf_reset(&header);
2322                goto free_ab_and_return;
2323        } else if (!DIFF_OPT_TST(o, TEXT) &&
2324            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2325              (!textconv_two && diff_filespec_is_binary(two)) )) {
2326                if (!one->data && !two->data &&
2327                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2328                    !DIFF_OPT_TST(o, BINARY)) {
2329                        if (!hashcmp(one->sha1, two->sha1)) {
2330                                if (must_show_header)
2331                                        fprintf(o->file, "%s", header.buf);
2332                                goto free_ab_and_return;
2333                        }
2334                        fprintf(o->file, "%s", header.buf);
2335                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2336                                line_prefix, lbl[0], lbl[1]);
2337                        goto free_ab_and_return;
2338                }
2339                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2340                        die("unable to read files to diff");
2341                /* Quite common confusing case */
2342                if (mf1.size == mf2.size &&
2343                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2344                        if (must_show_header)
2345                                fprintf(o->file, "%s", header.buf);
2346                        goto free_ab_and_return;
2347                }
2348                fprintf(o->file, "%s", header.buf);
2349                strbuf_reset(&header);
2350                if (DIFF_OPT_TST(o, BINARY))
2351                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2352                else
2353                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2354                                line_prefix, lbl[0], lbl[1]);
2355                o->found_changes = 1;
2356        } else {
2357                /* Crazy xdl interfaces.. */
2358                const char *diffopts = getenv("GIT_DIFF_OPTS");
2359                const char *v;
2360                xpparam_t xpp;
2361                xdemitconf_t xecfg;
2362                struct emit_callback ecbdata;
2363                const struct userdiff_funcname *pe;
2364
2365                if (must_show_header) {
2366                        fprintf(o->file, "%s", header.buf);
2367                        strbuf_reset(&header);
2368                }
2369
2370                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2371                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2372
2373                pe = diff_funcname_pattern(one);
2374                if (!pe)
2375                        pe = diff_funcname_pattern(two);
2376
2377                memset(&xpp, 0, sizeof(xpp));
2378                memset(&xecfg, 0, sizeof(xecfg));
2379                memset(&ecbdata, 0, sizeof(ecbdata));
2380                ecbdata.label_path = lbl;
2381                ecbdata.color_diff = want_color(o->use_color);
2382                ecbdata.found_changesp = &o->found_changes;
2383                ecbdata.ws_rule = whitespace_rule(name_b);
2384                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2385                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2386                ecbdata.opt = o;
2387                ecbdata.header = header.len ? &header : NULL;
2388                xpp.flags = o->xdl_opts;
2389                xecfg.ctxlen = o->context;
2390                xecfg.interhunkctxlen = o->interhunkcontext;
2391                xecfg.flags = XDL_EMIT_FUNCNAMES;
2392                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2393                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2394                if (pe)
2395                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2396                if (!diffopts)
2397                        ;
2398                else if (skip_prefix(diffopts, "--unified=", &v))
2399                        xecfg.ctxlen = strtoul(v, NULL, 10);
2400                else if (skip_prefix(diffopts, "-u", &v))
2401                        xecfg.ctxlen = strtoul(v, NULL, 10);
2402                if (o->word_diff)
2403                        init_diff_words_data(&ecbdata, o, one, two);
2404                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2405                              &xpp, &xecfg);
2406                if (o->word_diff)
2407                        free_diff_words_data(&ecbdata);
2408                if (textconv_one)
2409                        free(mf1.ptr);
2410                if (textconv_two)
2411                        free(mf2.ptr);
2412                xdiff_clear_find_func(&xecfg);
2413        }
2414
2415 free_ab_and_return:
2416        strbuf_release(&header);
2417        diff_free_filespec_data(one);
2418        diff_free_filespec_data(two);
2419        free(a_one);
2420        free(b_two);
2421        return;
2422}
2423
2424static void builtin_diffstat(const char *name_a, const char *name_b,
2425                             struct diff_filespec *one,
2426                             struct diff_filespec *two,
2427                             struct diffstat_t *diffstat,
2428                             struct diff_options *o,
2429                             struct diff_filepair *p)
2430{
2431        mmfile_t mf1, mf2;
2432        struct diffstat_file *data;
2433        int same_contents;
2434        int complete_rewrite = 0;
2435
2436        if (!DIFF_PAIR_UNMERGED(p)) {
2437                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2438                        complete_rewrite = 1;
2439        }
2440
2441        data = diffstat_add(diffstat, name_a, name_b);
2442        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2443
2444        if (!one || !two) {
2445                data->is_unmerged = 1;
2446                return;
2447        }
2448
2449        same_contents = !hashcmp(one->sha1, two->sha1);
2450
2451        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2452                data->is_binary = 1;
2453                if (same_contents) {
2454                        data->added = 0;
2455                        data->deleted = 0;
2456                } else {
2457                        data->added = diff_filespec_size(two);
2458                        data->deleted = diff_filespec_size(one);
2459                }
2460        }
2461
2462        else if (complete_rewrite) {
2463                diff_populate_filespec(one, 0);
2464                diff_populate_filespec(two, 0);
2465                data->deleted = count_lines(one->data, one->size);
2466                data->added = count_lines(two->data, two->size);
2467        }
2468
2469        else if (!same_contents) {
2470                /* Crazy xdl interfaces.. */
2471                xpparam_t xpp;
2472                xdemitconf_t xecfg;
2473
2474                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2475                        die("unable to read files to diff");
2476
2477                memset(&xpp, 0, sizeof(xpp));
2478                memset(&xecfg, 0, sizeof(xecfg));
2479                xpp.flags = o->xdl_opts;
2480                xecfg.ctxlen = o->context;
2481                xecfg.interhunkctxlen = o->interhunkcontext;
2482                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2483                              &xpp, &xecfg);
2484        }
2485
2486        diff_free_filespec_data(one);
2487        diff_free_filespec_data(two);
2488}
2489
2490static void builtin_checkdiff(const char *name_a, const char *name_b,
2491                              const char *attr_path,
2492                              struct diff_filespec *one,
2493                              struct diff_filespec *two,
2494                              struct diff_options *o)
2495{
2496        mmfile_t mf1, mf2;
2497        struct checkdiff_t data;
2498
2499        if (!two)
2500                return;
2501
2502        memset(&data, 0, sizeof(data));
2503        data.filename = name_b ? name_b : name_a;
2504        data.lineno = 0;
2505        data.o = o;
2506        data.ws_rule = whitespace_rule(attr_path);
2507        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2508
2509        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2510                die("unable to read files to diff");
2511
2512        /*
2513         * All the other codepaths check both sides, but not checking
2514         * the "old" side here is deliberate.  We are checking the newly
2515         * introduced changes, and as long as the "new" side is text, we
2516         * can and should check what it introduces.
2517         */
2518        if (diff_filespec_is_binary(two))
2519                goto free_and_return;
2520        else {
2521                /* Crazy xdl interfaces.. */
2522                xpparam_t xpp;
2523                xdemitconf_t xecfg;
2524
2525                memset(&xpp, 0, sizeof(xpp));
2526                memset(&xecfg, 0, sizeof(xecfg));
2527                xecfg.ctxlen = 1; /* at least one context line */
2528                xpp.flags = 0;
2529                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2530                              &xpp, &xecfg);
2531
2532                if (data.ws_rule & WS_BLANK_AT_EOF) {
2533                        struct emit_callback ecbdata;
2534                        int blank_at_eof;
2535
2536                        ecbdata.ws_rule = data.ws_rule;
2537                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2538                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2539
2540                        if (blank_at_eof) {
2541                                static char *err;
2542                                if (!err)
2543                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2544                                fprintf(o->file, "%s:%d: %s.\n",
2545                                        data.filename, blank_at_eof, err);
2546                                data.status = 1; /* report errors */
2547                        }
2548                }
2549        }
2550 free_and_return:
2551        diff_free_filespec_data(one);
2552        diff_free_filespec_data(two);
2553        if (data.status)
2554                DIFF_OPT_SET(o, CHECK_FAILED);
2555}
2556
2557struct diff_filespec *alloc_filespec(const char *path)
2558{
2559        int namelen = strlen(path);
2560        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2561
2562        memset(spec, 0, sizeof(*spec));
2563        spec->path = (char *)(spec + 1);
2564        memcpy(spec->path, path, namelen+1);
2565        spec->count = 1;
2566        spec->is_binary = -1;
2567        return spec;
2568}
2569
2570void free_filespec(struct diff_filespec *spec)
2571{
2572        if (!--spec->count) {
2573                diff_free_filespec_data(spec);
2574                free(spec);
2575        }
2576}
2577
2578void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2579                   int sha1_valid, unsigned short mode)
2580{
2581        if (mode) {
2582                spec->mode = canon_mode(mode);
2583                hashcpy(spec->sha1, sha1);
2584                spec->sha1_valid = sha1_valid;
2585        }
2586}
2587
2588/*
2589 * Given a name and sha1 pair, if the index tells us the file in
2590 * the work tree has that object contents, return true, so that
2591 * prepare_temp_file() does not have to inflate and extract.
2592 */
2593static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2594{
2595        const struct cache_entry *ce;
2596        struct stat st;
2597        int pos, len;
2598
2599        /*
2600         * We do not read the cache ourselves here, because the
2601         * benchmark with my previous version that always reads cache
2602         * shows that it makes things worse for diff-tree comparing
2603         * two linux-2.6 kernel trees in an already checked out work
2604         * tree.  This is because most diff-tree comparisons deal with
2605         * only a small number of files, while reading the cache is
2606         * expensive for a large project, and its cost outweighs the
2607         * savings we get by not inflating the object to a temporary
2608         * file.  Practically, this code only helps when we are used
2609         * by diff-cache --cached, which does read the cache before
2610         * calling us.
2611         */
2612        if (!active_cache)
2613                return 0;
2614
2615        /* We want to avoid the working directory if our caller
2616         * doesn't need the data in a normal file, this system
2617         * is rather slow with its stat/open/mmap/close syscalls,
2618         * and the object is contained in a pack file.  The pack
2619         * is probably already open and will be faster to obtain
2620         * the data through than the working directory.  Loose
2621         * objects however would tend to be slower as they need
2622         * to be individually opened and inflated.
2623         */
2624        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2625                return 0;
2626
2627        len = strlen(name);
2628        pos = cache_name_pos(name, len);
2629        if (pos < 0)
2630                return 0;
2631        ce = active_cache[pos];
2632
2633        /*
2634         * This is not the sha1 we are looking for, or
2635         * unreusable because it is not a regular file.
2636         */
2637        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2638                return 0;
2639
2640        /*
2641         * If ce is marked as "assume unchanged", there is no
2642         * guarantee that work tree matches what we are looking for.
2643         */
2644        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2645                return 0;
2646
2647        /*
2648         * If ce matches the file in the work tree, we can reuse it.
2649         */
2650        if (ce_uptodate(ce) ||
2651            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2652                return 1;
2653
2654        return 0;
2655}
2656
2657static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2658{
2659        int len;
2660        char *data = xmalloc(100), *dirty = "";
2661
2662        /* Are we looking at the work tree? */
2663        if (s->dirty_submodule)
2664                dirty = "-dirty";
2665
2666        len = snprintf(data, 100,
2667                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2668        s->data = data;
2669        s->size = len;
2670        s->should_free = 1;
2671        if (size_only) {
2672                s->data = NULL;
2673                free(data);
2674        }
2675        return 0;
2676}
2677
2678/*
2679 * While doing rename detection and pickaxe operation, we may need to
2680 * grab the data for the blob (or file) for our own in-core comparison.
2681 * diff_filespec has data and size fields for this purpose.
2682 */
2683int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2684{
2685        int size_only = flags & CHECK_SIZE_ONLY;
2686        int err = 0;
2687        /*
2688         * demote FAIL to WARN to allow inspecting the situation
2689         * instead of refusing.
2690         */
2691        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2692                                    ? SAFE_CRLF_WARN
2693                                    : safe_crlf);
2694
2695        if (!DIFF_FILE_VALID(s))
2696                die("internal error: asking to populate invalid file.");
2697        if (S_ISDIR(s->mode))
2698                return -1;
2699
2700        if (s->data)
2701                return 0;
2702
2703        if (size_only && 0 < s->size)
2704                return 0;
2705
2706        if (S_ISGITLINK(s->mode))
2707                return diff_populate_gitlink(s, size_only);
2708
2709        if (!s->sha1_valid ||
2710            reuse_worktree_file(s->path, s->sha1, 0)) {
2711                struct strbuf buf = STRBUF_INIT;
2712                struct stat st;
2713                int fd;
2714
2715                if (lstat(s->path, &st) < 0) {
2716                        if (errno == ENOENT) {
2717                        err_empty:
2718                                err = -1;
2719                        empty:
2720                                s->data = (char *)"";
2721                                s->size = 0;
2722                                return err;
2723                        }
2724                }
2725                s->size = xsize_t(st.st_size);
2726                if (!s->size)
2727                        goto empty;
2728                if (S_ISLNK(st.st_mode)) {
2729                        struct strbuf sb = STRBUF_INIT;
2730
2731                        if (strbuf_readlink(&sb, s->path, s->size))
2732                                goto err_empty;
2733                        s->size = sb.len;
2734                        s->data = strbuf_detach(&sb, NULL);
2735                        s->should_free = 1;
2736                        return 0;
2737                }
2738                if (size_only)
2739                        return 0;
2740                if ((flags & CHECK_BINARY) &&
2741                    s->size > big_file_threshold && s->is_binary == -1) {
2742                        s->is_binary = 1;
2743                        return 0;
2744                }
2745                fd = open(s->path, O_RDONLY);
2746                if (fd < 0)
2747                        goto err_empty;
2748                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2749                close(fd);
2750                s->should_munmap = 1;
2751
2752                /*
2753                 * Convert from working tree format to canonical git format
2754                 */
2755                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2756                        size_t size = 0;
2757                        munmap(s->data, s->size);
2758                        s->should_munmap = 0;
2759                        s->data = strbuf_detach(&buf, &size);
2760                        s->size = size;
2761                        s->should_free = 1;
2762                }
2763        }
2764        else {
2765                enum object_type type;
2766                if (size_only || (flags & CHECK_BINARY)) {
2767                        type = sha1_object_info(s->sha1, &s->size);
2768                        if (type < 0)
2769                                die("unable to read %s", sha1_to_hex(s->sha1));
2770                        if (size_only)
2771                                return 0;
2772                        if (s->size > big_file_threshold && s->is_binary == -1) {
2773                                s->is_binary = 1;
2774                                return 0;
2775                        }
2776                }
2777                s->data = read_sha1_file(s->sha1, &type, &s->size);
2778                if (!s->data)
2779                        die("unable to read %s", sha1_to_hex(s->sha1));
2780                s->should_free = 1;
2781        }
2782        return 0;
2783}
2784
2785void diff_free_filespec_blob(struct diff_filespec *s)
2786{
2787        if (s->should_free)
2788                free(s->data);
2789        else if (s->should_munmap)
2790                munmap(s->data, s->size);
2791
2792        if (s->should_free || s->should_munmap) {
2793                s->should_free = s->should_munmap = 0;
2794                s->data = NULL;
2795        }
2796}
2797
2798void diff_free_filespec_data(struct diff_filespec *s)
2799{
2800        diff_free_filespec_blob(s);
2801        free(s->cnt_data);
2802        s->cnt_data = NULL;
2803}
2804
2805static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2806                           void *blob,
2807                           unsigned long size,
2808                           const unsigned char *sha1,
2809                           int mode)
2810{
2811        int fd;
2812        struct strbuf buf = STRBUF_INIT;
2813        struct strbuf template = STRBUF_INIT;
2814        char *path_dup = xstrdup(path);
2815        const char *base = basename(path_dup);
2816
2817        /* Generate "XXXXXX_basename.ext" */
2818        strbuf_addstr(&template, "XXXXXX_");
2819        strbuf_addstr(&template, base);
2820
2821        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2822                        strlen(base) + 1);
2823        if (fd < 0)
2824                die_errno("unable to create temp-file");
2825        if (convert_to_working_tree(path,
2826                        (const char *)blob, (size_t)size, &buf)) {
2827                blob = buf.buf;
2828                size = buf.len;
2829        }
2830        if (write_in_full(fd, blob, size) != size)
2831                die_errno("unable to write temp-file");
2832        close(fd);
2833        temp->name = temp->tmp_path;
2834        strcpy(temp->hex, sha1_to_hex(sha1));
2835        temp->hex[40] = 0;
2836        sprintf(temp->mode, "%06o", mode);
2837        strbuf_release(&buf);
2838        strbuf_release(&template);
2839        free(path_dup);
2840}
2841
2842static struct diff_tempfile *prepare_temp_file(const char *name,
2843                struct diff_filespec *one)
2844{
2845        struct diff_tempfile *temp = claim_diff_tempfile();
2846
2847        if (!DIFF_FILE_VALID(one)) {
2848        not_a_valid_file:
2849                /* A '-' entry produces this for file-2, and
2850                 * a '+' entry produces this for file-1.
2851                 */
2852                temp->name = "/dev/null";
2853                strcpy(temp->hex, ".");
2854                strcpy(temp->mode, ".");
2855                return temp;
2856        }
2857
2858        if (!remove_tempfile_installed) {
2859                atexit(remove_tempfile);
2860                sigchain_push_common(remove_tempfile_on_signal);
2861                remove_tempfile_installed = 1;
2862        }
2863
2864        if (!S_ISGITLINK(one->mode) &&
2865            (!one->sha1_valid ||
2866             reuse_worktree_file(name, one->sha1, 1))) {
2867                struct stat st;
2868                if (lstat(name, &st) < 0) {
2869                        if (errno == ENOENT)
2870                                goto not_a_valid_file;
2871                        die_errno("stat(%s)", name);
2872                }
2873                if (S_ISLNK(st.st_mode)) {
2874                        struct strbuf sb = STRBUF_INIT;
2875                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2876                                die_errno("readlink(%s)", name);
2877                        prep_temp_blob(name, temp, sb.buf, sb.len,
2878                                       (one->sha1_valid ?
2879                                        one->sha1 : null_sha1),
2880                                       (one->sha1_valid ?
2881                                        one->mode : S_IFLNK));
2882                        strbuf_release(&sb);
2883                }
2884                else {
2885                        /* we can borrow from the file in the work tree */
2886                        temp->name = name;
2887                        if (!one->sha1_valid)
2888                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2889                        else
2890                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2891                        /* Even though we may sometimes borrow the
2892                         * contents from the work tree, we always want
2893                         * one->mode.  mode is trustworthy even when
2894                         * !(one->sha1_valid), as long as
2895                         * DIFF_FILE_VALID(one).
2896                         */
2897                        sprintf(temp->mode, "%06o", one->mode);
2898                }
2899                return temp;
2900        }
2901        else {
2902                if (diff_populate_filespec(one, 0))
2903                        die("cannot read data blob for %s", one->path);
2904                prep_temp_blob(name, temp, one->data, one->size,
2905                               one->sha1, one->mode);
2906        }
2907        return temp;
2908}
2909
2910static void add_external_diff_name(struct argv_array *argv,
2911                                   const char *name,
2912                                   struct diff_filespec *df)
2913{
2914        struct diff_tempfile *temp = prepare_temp_file(name, df);
2915        argv_array_push(argv, temp->name);
2916        argv_array_push(argv, temp->hex);
2917        argv_array_push(argv, temp->mode);
2918}
2919
2920/* An external diff command takes:
2921 *
2922 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2923 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2924 *
2925 */
2926static void run_external_diff(const char *pgm,
2927                              const char *name,
2928                              const char *other,
2929                              struct diff_filespec *one,
2930                              struct diff_filespec *two,
2931                              const char *xfrm_msg,
2932                              int complete_rewrite,
2933                              struct diff_options *o)
2934{
2935        struct argv_array argv = ARGV_ARRAY_INIT;
2936        struct argv_array env = ARGV_ARRAY_INIT;
2937        struct diff_queue_struct *q = &diff_queued_diff;
2938
2939        argv_array_push(&argv, pgm);
2940        argv_array_push(&argv, name);
2941
2942        if (one && two) {
2943                add_external_diff_name(&argv, name, one);
2944                if (!other)
2945                        add_external_diff_name(&argv, name, two);
2946                else {
2947                        add_external_diff_name(&argv, other, two);
2948                        argv_array_push(&argv, other);
2949                        argv_array_push(&argv, xfrm_msg);
2950                }
2951        }
2952
2953        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2954        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2955
2956        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2957                die(_("external diff died, stopping at %s"), name);
2958
2959        remove_tempfile();
2960        argv_array_clear(&argv);
2961        argv_array_clear(&env);
2962}
2963
2964static int similarity_index(struct diff_filepair *p)
2965{
2966        return p->score * 100 / MAX_SCORE;
2967}
2968
2969static void fill_metainfo(struct strbuf *msg,
2970                          const char *name,
2971                          const char *other,
2972                          struct diff_filespec *one,
2973                          struct diff_filespec *two,
2974                          struct diff_options *o,
2975                          struct diff_filepair *p,
2976                          int *must_show_header,
2977                          int use_color)
2978{
2979        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2980        const char *reset = diff_get_color(use_color, DIFF_RESET);
2981        const char *line_prefix = diff_line_prefix(o);
2982
2983        *must_show_header = 1;
2984        strbuf_init(msg, PATH_MAX * 2 + 300);
2985        switch (p->status) {
2986        case DIFF_STATUS_COPIED:
2987                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2988                            line_prefix, set, similarity_index(p));
2989                strbuf_addf(msg, "%s\n%s%scopy from ",
2990                            reset,  line_prefix, set);
2991                quote_c_style(name, msg, NULL, 0);
2992                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2993                quote_c_style(other, msg, NULL, 0);
2994                strbuf_addf(msg, "%s\n", reset);
2995                break;
2996        case DIFF_STATUS_RENAMED:
2997                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2998                            line_prefix, set, similarity_index(p));
2999                strbuf_addf(msg, "%s\n%s%srename from ",
3000                            reset, line_prefix, set);
3001                quote_c_style(name, msg, NULL, 0);
3002                strbuf_addf(msg, "%s\n%s%srename to ",
3003                            reset, line_prefix, set);
3004                quote_c_style(other, msg, NULL, 0);
3005                strbuf_addf(msg, "%s\n", reset);
3006                break;
3007        case DIFF_STATUS_MODIFIED:
3008                if (p->score) {
3009                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3010                                    line_prefix,
3011                                    set, similarity_index(p), reset);
3012                        break;
3013                }
3014                /* fallthru */
3015        default:
3016                *must_show_header = 0;
3017        }
3018        if (one && two && hashcmp(one->sha1, two->sha1)) {
3019                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3020
3021                if (DIFF_OPT_TST(o, BINARY)) {
3022                        mmfile_t mf;
3023                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3024                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3025                                abbrev = 40;
3026                }
3027                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3028                            find_unique_abbrev(one->sha1, abbrev));
3029                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3030                if (one->mode == two->mode)
3031                        strbuf_addf(msg, " %06o", one->mode);
3032                strbuf_addf(msg, "%s\n", reset);
3033        }
3034}
3035
3036static void run_diff_cmd(const char *pgm,
3037                         const char *name,
3038                         const char *other,
3039                         const char *attr_path,
3040                         struct diff_filespec *one,
3041                         struct diff_filespec *two,
3042                         struct strbuf *msg,
3043                         struct diff_options *o,
3044                         struct diff_filepair *p)
3045{
3046        const char *xfrm_msg = NULL;
3047        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3048        int must_show_header = 0;
3049
3050
3051        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3052                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3053                if (drv && drv->external)
3054                        pgm = drv->external;
3055        }
3056
3057        if (msg) {
3058                /*
3059                 * don't use colors when the header is intended for an
3060                 * external diff driver
3061                 */
3062                fill_metainfo(msg, name, other, one, two, o, p,
3063                              &must_show_header,
3064                              want_color(o->use_color) && !pgm);
3065                xfrm_msg = msg->len ? msg->buf : NULL;
3066        }
3067
3068        if (pgm) {
3069                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3070                                  complete_rewrite, o);
3071                return;
3072        }
3073        if (one && two)
3074                builtin_diff(name, other ? other : name,
3075                             one, two, xfrm_msg, must_show_header,
3076                             o, complete_rewrite);
3077        else
3078                fprintf(o->file, "* Unmerged path %s\n", name);
3079}
3080
3081static void diff_fill_sha1_info(struct diff_filespec *one)
3082{
3083        if (DIFF_FILE_VALID(one)) {
3084                if (!one->sha1_valid) {
3085                        struct stat st;
3086                        if (one->is_stdin) {
3087                                hashcpy(one->sha1, null_sha1);
3088                                return;
3089                        }
3090                        if (lstat(one->path, &st) < 0)
3091                                die_errno("stat '%s'", one->path);
3092                        if (index_path(one->sha1, one->path, &st, 0))
3093                                die("cannot hash %s", one->path);
3094                }
3095        }
3096        else
3097                hashclr(one->sha1);
3098}
3099
3100static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3101{
3102        /* Strip the prefix but do not molest /dev/null and absolute paths */
3103        if (*namep && **namep != '/') {
3104                *namep += prefix_length;
3105                if (**namep == '/')
3106                        ++*namep;
3107        }
3108        if (*otherp && **otherp != '/') {
3109                *otherp += prefix_length;
3110                if (**otherp == '/')
3111                        ++*otherp;
3112        }
3113}
3114
3115static void run_diff(struct diff_filepair *p, struct diff_options *o)
3116{
3117        const char *pgm = external_diff();
3118        struct strbuf msg;
3119        struct diff_filespec *one = p->one;
3120        struct diff_filespec *two = p->two;
3121        const char *name;
3122        const char *other;
3123        const char *attr_path;
3124
3125        name  = p->one->path;
3126        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3127        attr_path = name;
3128        if (o->prefix_length)
3129                strip_prefix(o->prefix_length, &name, &other);
3130
3131        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3132                pgm = NULL;
3133
3134        if (DIFF_PAIR_UNMERGED(p)) {
3135                run_diff_cmd(pgm, name, NULL, attr_path,
3136                             NULL, NULL, NULL, o, p);
3137                return;
3138        }
3139
3140        diff_fill_sha1_info(one);
3141        diff_fill_sha1_info(two);
3142
3143        if (!pgm &&
3144            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3145            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3146                /*
3147                 * a filepair that changes between file and symlink
3148                 * needs to be split into deletion and creation.
3149                 */
3150                struct diff_filespec *null = alloc_filespec(two->path);
3151                run_diff_cmd(NULL, name, other, attr_path,
3152                             one, null, &msg, o, p);
3153                free(null);
3154                strbuf_release(&msg);
3155
3156                null = alloc_filespec(one->path);
3157                run_diff_cmd(NULL, name, other, attr_path,
3158                             null, two, &msg, o, p);
3159                free(null);
3160        }
3161        else
3162                run_diff_cmd(pgm, name, other, attr_path,
3163                             one, two, &msg, o, p);
3164
3165        strbuf_release(&msg);
3166}
3167
3168static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3169                         struct diffstat_t *diffstat)
3170{
3171        const char *name;
3172        const char *other;
3173
3174        if (DIFF_PAIR_UNMERGED(p)) {
3175                /* unmerged */
3176                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3177                return;
3178        }
3179
3180        name = p->one->path;
3181        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3182
3183        if (o->prefix_length)
3184                strip_prefix(o->prefix_length, &name, &other);
3185
3186        diff_fill_sha1_info(p->one);
3187        diff_fill_sha1_info(p->two);
3188
3189        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3190}
3191
3192static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3193{
3194        const char *name;
3195        const char *other;
3196        const char *attr_path;
3197
3198        if (DIFF_PAIR_UNMERGED(p)) {
3199                /* unmerged */
3200                return;
3201        }
3202
3203        name = p->one->path;
3204        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3205        attr_path = other ? other : name;
3206
3207        if (o->prefix_length)
3208                strip_prefix(o->prefix_length, &name, &other);
3209
3210        diff_fill_sha1_info(p->one);
3211        diff_fill_sha1_info(p->two);
3212
3213        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3214}
3215
3216void diff_setup(struct diff_options *options)
3217{
3218        memcpy(options, &default_diff_options, sizeof(*options));
3219
3220        options->file = stdout;
3221
3222        options->line_termination = '\n';
3223        options->break_opt = -1;
3224        options->rename_limit = -1;
3225        options->dirstat_permille = diff_dirstat_permille_default;
3226        options->context = diff_context_default;
3227        DIFF_OPT_SET(options, RENAME_EMPTY);
3228
3229        /* pathchange left =NULL by default */
3230        options->change = diff_change;
3231        options->add_remove = diff_addremove;
3232        options->use_color = diff_use_color_default;
3233        options->detect_rename = diff_detect_rename_default;
3234        options->xdl_opts |= diff_algorithm;
3235
3236        options->orderfile = diff_order_file_cfg;
3237
3238        if (diff_no_prefix) {
3239                options->a_prefix = options->b_prefix = "";
3240        } else if (!diff_mnemonic_prefix) {
3241                options->a_prefix = "a/";
3242                options->b_prefix = "b/";
3243        }
3244}
3245
3246void diff_setup_done(struct diff_options *options)
3247{
3248        int count = 0;
3249
3250        if (options->set_default)
3251                options->set_default(options);
3252
3253        if (options->output_format & DIFF_FORMAT_NAME)
3254                count++;
3255        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3256                count++;
3257        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3258                count++;
3259        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3260                count++;
3261        if (count > 1)
3262                die("--name-only, --name-status, --check and -s are mutually exclusive");
3263
3264        /*
3265         * Most of the time we can say "there are changes"
3266         * only by checking if there are changed paths, but
3267         * --ignore-whitespace* options force us to look
3268         * inside contents.
3269         */
3270
3271        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3272            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3273            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3274                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3275        else
3276                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3277
3278        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3279                options->detect_rename = DIFF_DETECT_COPY;
3280
3281        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3282                options->prefix = NULL;
3283        if (options->prefix)
3284                options->prefix_length = strlen(options->prefix);
3285        else
3286                options->prefix_length = 0;
3287
3288        if (options->output_format & (DIFF_FORMAT_NAME |
3289                                      DIFF_FORMAT_NAME_STATUS |
3290                                      DIFF_FORMAT_CHECKDIFF |
3291                                      DIFF_FORMAT_NO_OUTPUT))
3292                options->output_format &= ~(DIFF_FORMAT_RAW |
3293                                            DIFF_FORMAT_NUMSTAT |
3294                                            DIFF_FORMAT_DIFFSTAT |
3295                                            DIFF_FORMAT_SHORTSTAT |
3296                                            DIFF_FORMAT_DIRSTAT |
3297                                            DIFF_FORMAT_SUMMARY |
3298                                            DIFF_FORMAT_PATCH);
3299
3300        /*
3301         * These cases always need recursive; we do not drop caller-supplied
3302         * recursive bits for other formats here.
3303         */
3304        if (options->output_format & (DIFF_FORMAT_PATCH |
3305                                      DIFF_FORMAT_NUMSTAT |
3306                                      DIFF_FORMAT_DIFFSTAT |
3307                                      DIFF_FORMAT_SHORTSTAT |
3308                                      DIFF_FORMAT_DIRSTAT |
3309                                      DIFF_FORMAT_SUMMARY |
3310                                      DIFF_FORMAT_CHECKDIFF))
3311                DIFF_OPT_SET(options, RECURSIVE);
3312        /*
3313         * Also pickaxe would not work very well if you do not say recursive
3314         */
3315        if (options->pickaxe)
3316                DIFF_OPT_SET(options, RECURSIVE);
3317        /*
3318         * When patches are generated, submodules diffed against the work tree
3319         * must be checked for dirtiness too so it can be shown in the output
3320         */
3321        if (options->output_format & DIFF_FORMAT_PATCH)
3322                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3323
3324        if (options->detect_rename && options->rename_limit < 0)
3325                options->rename_limit = diff_rename_limit_default;
3326        if (options->setup & DIFF_SETUP_USE_CACHE) {
3327                if (!active_cache)
3328                        /* read-cache does not die even when it fails
3329                         * so it is safe for us to do this here.  Also
3330                         * it does not smudge active_cache or active_nr
3331                         * when it fails, so we do not have to worry about
3332                         * cleaning it up ourselves either.
3333                         */
3334                        read_cache();
3335        }
3336        if (options->abbrev <= 0 || 40 < options->abbrev)
3337                options->abbrev = 40; /* full */
3338
3339        /*
3340         * It does not make sense to show the first hit we happened
3341         * to have found.  It does not make sense not to return with
3342         * exit code in such a case either.
3343         */
3344        if (DIFF_OPT_TST(options, QUICK)) {
3345                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3346                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3347        }
3348
3349        options->diff_path_counter = 0;
3350
3351        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3352                die(_("--follow requires exactly one pathspec"));
3353}
3354
3355static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3356{
3357        char c, *eq;
3358        int len;
3359
3360        if (*arg != '-')
3361                return 0;
3362        c = *++arg;
3363        if (!c)
3364                return 0;
3365        if (c == arg_short) {
3366                c = *++arg;
3367                if (!c)
3368                        return 1;
3369                if (val && isdigit(c)) {
3370                        char *end;
3371                        int n = strtoul(arg, &end, 10);
3372                        if (*end)
3373                                return 0;
3374                        *val = n;
3375                        return 1;
3376                }
3377                return 0;
3378        }
3379        if (c != '-')
3380                return 0;
3381        arg++;
3382        eq = strchrnul(arg, '=');
3383        len = eq - arg;
3384        if (!len || strncmp(arg, arg_long, len))
3385                return 0;
3386        if (*eq) {
3387                int n;
3388                char *end;
3389                if (!isdigit(*++eq))
3390                        return 0;
3391                n = strtoul(eq, &end, 10);
3392                if (*end)
3393                        return 0;
3394                *val = n;
3395        }
3396        return 1;
3397}
3398
3399static int diff_scoreopt_parse(const char *opt);
3400
3401static inline int short_opt(char opt, const char **argv,
3402                            const char **optarg)
3403{
3404        const char *arg = argv[0];
3405        if (arg[0] != '-' || arg[1] != opt)
3406                return 0;
3407        if (arg[2] != '\0') {
3408                *optarg = arg + 2;
3409                return 1;
3410        }
3411        if (!argv[1])
3412                die("Option '%c' requires a value", opt);
3413        *optarg = argv[1];
3414        return 2;
3415}
3416
3417int parse_long_opt(const char *opt, const char **argv,
3418                   const char **optarg)
3419{
3420        const char *arg = argv[0];
3421        if (!skip_prefix(arg, "--", &arg))
3422                return 0;
3423        if (!skip_prefix(arg, opt, &arg))
3424                return 0;
3425        if (*arg == '=') { /* stuck form: --option=value */
3426                *optarg = arg + 1;
3427                return 1;
3428        }
3429        if (*arg != '\0')
3430                return 0;
3431        /* separate form: --option value */
3432        if (!argv[1])
3433                die("Option '--%s' requires a value", opt);
3434        *optarg = argv[1];
3435        return 2;
3436}
3437
3438static int stat_opt(struct diff_options *options, const char **av)
3439{
3440        const char *arg = av[0];
3441        char *end;
3442        int width = options->stat_width;
3443        int name_width = options->stat_name_width;
3444        int graph_width = options->stat_graph_width;
3445        int count = options->stat_count;
3446        int argcount = 1;
3447
3448        if (!skip_prefix(arg, "--stat", &arg))
3449                die("BUG: stat option does not begin with --stat: %s", arg);
3450        end = (char *)arg;
3451
3452        switch (*arg) {
3453        case '-':
3454                if (skip_prefix(arg, "-width", &arg)) {
3455                        if (*arg == '=')
3456                                width = strtoul(arg + 1, &end, 10);
3457                        else if (!*arg && !av[1])
3458                                die("Option '--stat-width' requires a value");
3459                        else if (!*arg) {
3460                                width = strtoul(av[1], &end, 10);
3461                                argcount = 2;
3462                        }
3463                } else if (skip_prefix(arg, "-name-width", &arg)) {
3464                        if (*arg == '=')
3465                                name_width = strtoul(arg + 1, &end, 10);
3466                        else if (!*arg && !av[1])
3467                                die("Option '--stat-name-width' requires a value");
3468                        else if (!*arg) {
3469                                name_width = strtoul(av[1], &end, 10);
3470                                argcount = 2;
3471                        }
3472                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3473                        if (*arg == '=')
3474                                graph_width = strtoul(arg + 1, &end, 10);
3475                        else if (!*arg && !av[1])
3476                                die("Option '--stat-graph-width' requires a value");
3477                        else if (!*arg) {
3478                                graph_width = strtoul(av[1], &end, 10);
3479                                argcount = 2;
3480                        }
3481                } else if (skip_prefix(arg, "-count", &arg)) {
3482                        if (*arg == '=')
3483                                count = strtoul(arg + 1, &end, 10);
3484                        else if (!*arg && !av[1])
3485                                die("Option '--stat-count' requires a value");
3486                        else if (!*arg) {
3487                                count = strtoul(av[1], &end, 10);
3488                                argcount = 2;
3489                        }
3490                }
3491                break;
3492        case '=':
3493                width = strtoul(arg+1, &end, 10);
3494                if (*end == ',')
3495                        name_width = strtoul(end+1, &end, 10);
3496                if (*end == ',')
3497                        count = strtoul(end+1, &end, 10);
3498        }
3499
3500        /* Important! This checks all the error cases! */
3501        if (*end)
3502                return 0;
3503        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3504        options->stat_name_width = name_width;
3505        options->stat_graph_width = graph_width;
3506        options->stat_width = width;
3507        options->stat_count = count;
3508        return argcount;
3509}
3510
3511static int parse_dirstat_opt(struct diff_options *options, const char *params)
3512{
3513        struct strbuf errmsg = STRBUF_INIT;
3514        if (parse_dirstat_params(options, params, &errmsg))
3515                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3516                    errmsg.buf);
3517        strbuf_release(&errmsg);
3518        /*
3519         * The caller knows a dirstat-related option is given from the command
3520         * line; allow it to say "return this_function();"
3521         */
3522        options->output_format |= DIFF_FORMAT_DIRSTAT;
3523        return 1;
3524}
3525
3526static int parse_submodule_opt(struct diff_options *options, const char *value)
3527{
3528        if (parse_submodule_params(options, value))
3529                die(_("Failed to parse --submodule option parameter: '%s'"),
3530                        value);
3531        return 1;
3532}
3533
3534static const char diff_status_letters[] = {
3535        DIFF_STATUS_ADDED,
3536        DIFF_STATUS_COPIED,
3537        DIFF_STATUS_DELETED,
3538        DIFF_STATUS_MODIFIED,
3539        DIFF_STATUS_RENAMED,
3540        DIFF_STATUS_TYPE_CHANGED,
3541        DIFF_STATUS_UNKNOWN,
3542        DIFF_STATUS_UNMERGED,
3543        DIFF_STATUS_FILTER_AON,
3544        DIFF_STATUS_FILTER_BROKEN,
3545        '\0',
3546};
3547
3548static unsigned int filter_bit['Z' + 1];
3549
3550static void prepare_filter_bits(void)
3551{
3552        int i;
3553
3554        if (!filter_bit[DIFF_STATUS_ADDED]) {
3555                for (i = 0; diff_status_letters[i]; i++)
3556                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3557        }
3558}
3559
3560static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3561{
3562        return opt->filter & filter_bit[(int) status];
3563}
3564
3565static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3566{
3567        int i, optch;
3568
3569        prepare_filter_bits();
3570
3571        /*
3572         * If there is a negation e.g. 'd' in the input, and we haven't
3573         * initialized the filter field with another --diff-filter, start
3574         * from full set of bits, except for AON.
3575         */
3576        if (!opt->filter) {
3577                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3578                        if (optch < 'a' || 'z' < optch)
3579                                continue;
3580                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3581                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3582                        break;
3583                }
3584        }
3585
3586        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3587                unsigned int bit;
3588                int negate;
3589
3590                if ('a' <= optch && optch <= 'z') {
3591                        negate = 1;
3592                        optch = toupper(optch);
3593                } else {
3594                        negate = 0;
3595                }
3596
3597                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3598                if (!bit)
3599                        return optarg[i];
3600                if (negate)
3601                        opt->filter &= ~bit;
3602                else
3603                        opt->filter |= bit;
3604        }
3605        return 0;
3606}
3607
3608static void enable_patch_output(int *fmt) {
3609        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3610        *fmt |= DIFF_FORMAT_PATCH;
3611}
3612
3613int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3614{
3615        const char *arg = av[0];
3616        const char *optarg;
3617        int argcount;
3618
3619        /* Output format options */
3620        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3621            || opt_arg(arg, 'U', "unified", &options->context))
3622                enable_patch_output(&options->output_format);
3623        else if (!strcmp(arg, "--raw"))
3624                options->output_format |= DIFF_FORMAT_RAW;
3625        else if (!strcmp(arg, "--patch-with-raw")) {
3626                enable_patch_output(&options->output_format);
3627                options->output_format |= DIFF_FORMAT_RAW;
3628        } else if (!strcmp(arg, "--numstat"))
3629                options->output_format |= DIFF_FORMAT_NUMSTAT;
3630        else if (!strcmp(arg, "--shortstat"))
3631                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3632        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3633                return parse_dirstat_opt(options, "");
3634        else if (skip_prefix(arg, "-X", &arg))
3635                return parse_dirstat_opt(options, arg);
3636        else if (skip_prefix(arg, "--dirstat=", &arg))
3637                return parse_dirstat_opt(options, arg);
3638        else if (!strcmp(arg, "--cumulative"))
3639                return parse_dirstat_opt(options, "cumulative");
3640        else if (!strcmp(arg, "--dirstat-by-file"))
3641                return parse_dirstat_opt(options, "files");
3642        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3643                parse_dirstat_opt(options, "files");
3644                return parse_dirstat_opt(options, arg);
3645        }
3646        else if (!strcmp(arg, "--check"))
3647                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3648        else if (!strcmp(arg, "--summary"))
3649                options->output_format |= DIFF_FORMAT_SUMMARY;
3650        else if (!strcmp(arg, "--patch-with-stat")) {
3651                enable_patch_output(&options->output_format);
3652                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3653        } else if (!strcmp(arg, "--name-only"))
3654                options->output_format |= DIFF_FORMAT_NAME;
3655        else if (!strcmp(arg, "--name-status"))
3656                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3657        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3658                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3659        else if (starts_with(arg, "--stat"))
3660                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3661                return stat_opt(options, av);
3662
3663        /* renames options */
3664        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3665                 !strcmp(arg, "--break-rewrites")) {
3666                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3667                        return error("invalid argument to -B: %s", arg+2);
3668        }
3669        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3670                 !strcmp(arg, "--find-renames")) {
3671                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3672                        return error("invalid argument to -M: %s", arg+2);
3673                options->detect_rename = DIFF_DETECT_RENAME;
3674        }
3675        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3676                options->irreversible_delete = 1;
3677        }
3678        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3679                 !strcmp(arg, "--find-copies")) {
3680                if (options->detect_rename == DIFF_DETECT_COPY)
3681                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3682                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3683                        return error("invalid argument to -C: %s", arg+2);
3684                options->detect_rename = DIFF_DETECT_COPY;
3685        }
3686        else if (!strcmp(arg, "--no-renames"))
3687                options->detect_rename = 0;
3688        else if (!strcmp(arg, "--rename-empty"))
3689                DIFF_OPT_SET(options, RENAME_EMPTY);
3690        else if (!strcmp(arg, "--no-rename-empty"))
3691                DIFF_OPT_CLR(options, RENAME_EMPTY);
3692        else if (!strcmp(arg, "--relative"))
3693                DIFF_OPT_SET(options, RELATIVE_NAME);
3694        else if (skip_prefix(arg, "--relative=", &arg)) {
3695                DIFF_OPT_SET(options, RELATIVE_NAME);
3696                options->prefix = arg;
3697        }
3698
3699        /* xdiff options */
3700        else if (!strcmp(arg, "--minimal"))
3701                DIFF_XDL_SET(options, NEED_MINIMAL);
3702        else if (!strcmp(arg, "--no-minimal"))
3703                DIFF_XDL_CLR(options, NEED_MINIMAL);
3704        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3705                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3706        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3707                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3708        else if (!strcmp(arg, "--ignore-space-at-eol"))
3709                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3710        else if (!strcmp(arg, "--ignore-blank-lines"))
3711                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3712        else if (!strcmp(arg, "--patience"))
3713                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3714        else if (!strcmp(arg, "--histogram"))
3715                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3716        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3717                long value = parse_algorithm_value(optarg);
3718                if (value < 0)
3719                        return error("option diff-algorithm accepts \"myers\", "
3720                                     "\"minimal\", \"patience\" and \"histogram\"");
3721                /* clear out previous settings */
3722                DIFF_XDL_CLR(options, NEED_MINIMAL);
3723                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3724                options->xdl_opts |= value;
3725                return argcount;
3726        }
3727
3728        /* flags options */
3729        else if (!strcmp(arg, "--binary")) {
3730                enable_patch_output(&options->output_format);
3731                DIFF_OPT_SET(options, BINARY);
3732        }
3733        else if (!strcmp(arg, "--full-index"))
3734                DIFF_OPT_SET(options, FULL_INDEX);
3735        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3736                DIFF_OPT_SET(options, TEXT);
3737        else if (!strcmp(arg, "-R"))
3738                DIFF_OPT_SET(options, REVERSE_DIFF);
3739        else if (!strcmp(arg, "--find-copies-harder"))
3740                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3741        else if (!strcmp(arg, "--follow"))
3742                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3743        else if (!strcmp(arg, "--no-follow"))
3744                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3745        else if (!strcmp(arg, "--color"))
3746                options->use_color = 1;
3747        else if (skip_prefix(arg, "--color=", &arg)) {
3748                int value = git_config_colorbool(NULL, arg);
3749                if (value < 0)
3750                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3751                options->use_color = value;
3752        }
3753        else if (!strcmp(arg, "--no-color"))
3754                options->use_color = 0;
3755        else if (!strcmp(arg, "--color-words")) {
3756                options->use_color = 1;
3757                options->word_diff = DIFF_WORDS_COLOR;
3758        }
3759        else if (skip_prefix(arg, "--color-words=", &arg)) {
3760                options->use_color = 1;
3761                options->word_diff = DIFF_WORDS_COLOR;
3762                options->word_regex = arg;
3763        }
3764        else if (!strcmp(arg, "--word-diff")) {
3765                if (options->word_diff == DIFF_WORDS_NONE)
3766                        options->word_diff = DIFF_WORDS_PLAIN;
3767        }
3768        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3769                if (!strcmp(arg, "plain"))
3770                        options->word_diff = DIFF_WORDS_PLAIN;
3771                else if (!strcmp(arg, "color")) {
3772                        options->use_color = 1;
3773                        options->word_diff = DIFF_WORDS_COLOR;
3774                }
3775                else if (!strcmp(arg, "porcelain"))
3776                        options->word_diff = DIFF_WORDS_PORCELAIN;
3777                else if (!strcmp(arg, "none"))
3778                        options->word_diff = DIFF_WORDS_NONE;
3779                else
3780                        die("bad --word-diff argument: %s", arg);
3781        }
3782        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3783                if (options->word_diff == DIFF_WORDS_NONE)
3784                        options->word_diff = DIFF_WORDS_PLAIN;
3785                options->word_regex = optarg;
3786                return argcount;
3787        }
3788        else if (!strcmp(arg, "--exit-code"))
3789                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3790        else if (!strcmp(arg, "--quiet"))
3791                DIFF_OPT_SET(options, QUICK);
3792        else if (!strcmp(arg, "--ext-diff"))
3793                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3794        else if (!strcmp(arg, "--no-ext-diff"))
3795                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3796        else if (!strcmp(arg, "--textconv"))
3797                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3798        else if (!strcmp(arg, "--no-textconv"))
3799                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3800        else if (!strcmp(arg, "--ignore-submodules")) {
3801                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3802                handle_ignore_submodules_arg(options, "all");
3803        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3804                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3805                handle_ignore_submodules_arg(options, arg);
3806        } else if (!strcmp(arg, "--submodule"))
3807                DIFF_OPT_SET(options, SUBMODULE_LOG);
3808        else if (skip_prefix(arg, "--submodule=", &arg))
3809                return parse_submodule_opt(options, arg);
3810
3811        /* misc options */
3812        else if (!strcmp(arg, "-z"))
3813                options->line_termination = 0;
3814        else if ((argcount = short_opt('l', av, &optarg))) {
3815                options->rename_limit = strtoul(optarg, NULL, 10);
3816                return argcount;
3817        }
3818        else if ((argcount = short_opt('S', av, &optarg))) {
3819                options->pickaxe = optarg;
3820                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3821                return argcount;
3822        } else if ((argcount = short_opt('G', av, &optarg))) {
3823                options->pickaxe = optarg;
3824                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3825                return argcount;
3826        }
3827        else if (!strcmp(arg, "--pickaxe-all"))
3828                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3829        else if (!strcmp(arg, "--pickaxe-regex"))
3830                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3831        else if ((argcount = short_opt('O', av, &optarg))) {
3832                options->orderfile = optarg;
3833                return argcount;
3834        }
3835        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3836                int offending = parse_diff_filter_opt(optarg, options);
3837                if (offending)
3838                        die("unknown change class '%c' in --diff-filter=%s",
3839                            offending, optarg);
3840                return argcount;
3841        }
3842        else if (!strcmp(arg, "--abbrev"))
3843                options->abbrev = DEFAULT_ABBREV;
3844        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3845                options->abbrev = strtoul(arg, NULL, 10);
3846                if (options->abbrev < MINIMUM_ABBREV)
3847                        options->abbrev = MINIMUM_ABBREV;
3848                else if (40 < options->abbrev)
3849                        options->abbrev = 40;
3850        }
3851        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3852                options->a_prefix = optarg;
3853                return argcount;
3854        }
3855        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3856                options->b_prefix = optarg;
3857                return argcount;
3858        }
3859        else if (!strcmp(arg, "--no-prefix"))
3860                options->a_prefix = options->b_prefix = "";
3861        else if (opt_arg(arg, '\0', "inter-hunk-context",
3862                         &options->interhunkcontext))
3863                ;
3864        else if (!strcmp(arg, "-W"))
3865                DIFF_OPT_SET(options, FUNCCONTEXT);
3866        else if (!strcmp(arg, "--function-context"))
3867                DIFF_OPT_SET(options, FUNCCONTEXT);
3868        else if (!strcmp(arg, "--no-function-context"))
3869                DIFF_OPT_CLR(options, FUNCCONTEXT);
3870        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3871                options->file = fopen(optarg, "w");
3872                if (!options->file)
3873                        die_errno("Could not open '%s'", optarg);
3874                options->close_file = 1;
3875                return argcount;
3876        } else
3877                return 0;
3878        return 1;
3879}
3880
3881int parse_rename_score(const char **cp_p)
3882{
3883        unsigned long num, scale;
3884        int ch, dot;
3885        const char *cp = *cp_p;
3886
3887        num = 0;
3888        scale = 1;
3889        dot = 0;
3890        for (;;) {
3891                ch = *cp;
3892                if ( !dot && ch == '.' ) {
3893                        scale = 1;
3894                        dot = 1;
3895                } else if ( ch == '%' ) {
3896                        scale = dot ? scale*100 : 100;
3897                        cp++;   /* % is always at the end */
3898                        break;
3899                } else if ( ch >= '0' && ch <= '9' ) {
3900                        if ( scale < 100000 ) {
3901                                scale *= 10;
3902                                num = (num*10) + (ch-'0');
3903                        }
3904                } else {
3905                        break;
3906                }
3907                cp++;
3908        }
3909        *cp_p = cp;
3910
3911        /* user says num divided by scale and we say internally that
3912         * is MAX_SCORE * num / scale.
3913         */
3914        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3915}
3916
3917static int diff_scoreopt_parse(const char *opt)
3918{
3919        int opt1, opt2, cmd;
3920
3921        if (*opt++ != '-')
3922                return -1;
3923        cmd = *opt++;
3924        if (cmd == '-') {
3925                /* convert the long-form arguments into short-form versions */
3926                if (skip_prefix(opt, "break-rewrites", &opt)) {
3927                        if (*opt == 0 || *opt++ == '=')
3928                                cmd = 'B';
3929                } else if (skip_prefix(opt, "find-copies", &opt)) {
3930                        if (*opt == 0 || *opt++ == '=')
3931                                cmd = 'C';
3932                } else if (skip_prefix(opt, "find-renames", &opt)) {
3933                        if (*opt == 0 || *opt++ == '=')
3934                                cmd = 'M';
3935                }
3936        }
3937        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3938                return -1; /* that is not a -M, -C, or -B option */
3939
3940        opt1 = parse_rename_score(&opt);
3941        if (cmd != 'B')
3942                opt2 = 0;
3943        else {
3944                if (*opt == 0)
3945                        opt2 = 0;
3946                else if (*opt != '/')
3947                        return -1; /* we expect -B80/99 or -B80 */
3948                else {
3949                        opt++;
3950                        opt2 = parse_rename_score(&opt);
3951                }
3952        }
3953        if (*opt != 0)
3954                return -1;
3955        return opt1 | (opt2 << 16);
3956}
3957
3958struct diff_queue_struct diff_queued_diff;
3959
3960void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3961{
3962        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
3963        queue->queue[queue->nr++] = dp;
3964}
3965
3966struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3967                                 struct diff_filespec *one,
3968                                 struct diff_filespec *two)
3969{
3970        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3971        dp->one = one;
3972        dp->two = two;
3973        if (queue)
3974                diff_q(queue, dp);
3975        return dp;
3976}
3977
3978void diff_free_filepair(struct diff_filepair *p)
3979{
3980        free_filespec(p->one);
3981        free_filespec(p->two);
3982        free(p);
3983}
3984
3985/* This is different from find_unique_abbrev() in that
3986 * it stuffs the result with dots for alignment.
3987 */
3988const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3989{
3990        int abblen;
3991        const char *abbrev;
3992        if (len == 40)
3993                return sha1_to_hex(sha1);
3994
3995        abbrev = find_unique_abbrev(sha1, len);
3996        abblen = strlen(abbrev);
3997        if (abblen < 37) {
3998                static char hex[41];
3999                if (len < abblen && abblen <= len + 2)
4000                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
4001                else
4002                        sprintf(hex, "%s...", abbrev);
4003                return hex;
4004        }
4005        return sha1_to_hex(sha1);
4006}
4007
4008static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4009{
4010        int line_termination = opt->line_termination;
4011        int inter_name_termination = line_termination ? '\t' : '\0';
4012
4013        fprintf(opt->file, "%s", diff_line_prefix(opt));
4014        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4015                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4016                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4017                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4018        }
4019        if (p->score) {
4020                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4021                        inter_name_termination);
4022        } else {
4023                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4024        }
4025
4026        if (p->status == DIFF_STATUS_COPIED ||
4027            p->status == DIFF_STATUS_RENAMED) {
4028                const char *name_a, *name_b;
4029                name_a = p->one->path;
4030                name_b = p->two->path;
4031                strip_prefix(opt->prefix_length, &name_a, &name_b);
4032                write_name_quoted(name_a, opt->file, inter_name_termination);
4033                write_name_quoted(name_b, opt->file, line_termination);
4034        } else {
4035                const char *name_a, *name_b;
4036                name_a = p->one->mode ? p->one->path : p->two->path;
4037                name_b = NULL;
4038                strip_prefix(opt->prefix_length, &name_a, &name_b);
4039                write_name_quoted(name_a, opt->file, line_termination);
4040        }
4041}
4042
4043int diff_unmodified_pair(struct diff_filepair *p)
4044{
4045        /* This function is written stricter than necessary to support
4046         * the currently implemented transformers, but the idea is to
4047         * let transformers to produce diff_filepairs any way they want,
4048         * and filter and clean them up here before producing the output.
4049         */
4050        struct diff_filespec *one = p->one, *two = p->two;
4051
4052        if (DIFF_PAIR_UNMERGED(p))
4053                return 0; /* unmerged is interesting */
4054
4055        /* deletion, addition, mode or type change
4056         * and rename are all interesting.
4057         */
4058        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4059            DIFF_PAIR_MODE_CHANGED(p) ||
4060            strcmp(one->path, two->path))
4061                return 0;
4062
4063        /* both are valid and point at the same path.  that is, we are
4064         * dealing with a change.
4065         */
4066        if (one->sha1_valid && two->sha1_valid &&
4067            !hashcmp(one->sha1, two->sha1) &&
4068            !one->dirty_submodule && !two->dirty_submodule)
4069                return 1; /* no change */
4070        if (!one->sha1_valid && !two->sha1_valid)
4071                return 1; /* both look at the same file on the filesystem. */
4072        return 0;
4073}
4074
4075static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4076{
4077        if (diff_unmodified_pair(p))
4078                return;
4079
4080        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4081            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4082                return; /* no tree diffs in patch format */
4083
4084        run_diff(p, o);
4085}
4086
4087static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4088                            struct diffstat_t *diffstat)
4089{
4090        if (diff_unmodified_pair(p))
4091                return;
4092
4093        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4094            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4095                return; /* no useful stat for tree diffs */
4096
4097        run_diffstat(p, o, diffstat);
4098}
4099
4100static void diff_flush_checkdiff(struct diff_filepair *p,
4101                struct diff_options *o)
4102{
4103        if (diff_unmodified_pair(p))
4104                return;
4105
4106        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4107            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4108                return; /* nothing to check in tree diffs */
4109
4110        run_checkdiff(p, o);
4111}
4112
4113int diff_queue_is_empty(void)
4114{
4115        struct diff_queue_struct *q = &diff_queued_diff;
4116        int i;
4117        for (i = 0; i < q->nr; i++)
4118                if (!diff_unmodified_pair(q->queue[i]))
4119                        return 0;
4120        return 1;
4121}
4122
4123#if DIFF_DEBUG
4124void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4125{
4126        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4127                x, one ? one : "",
4128                s->path,
4129                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4130                s->mode,
4131                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4132        fprintf(stderr, "queue[%d] %s size %lu\n",
4133                x, one ? one : "",
4134                s->size);
4135}
4136
4137void diff_debug_filepair(const struct diff_filepair *p, int i)
4138{
4139        diff_debug_filespec(p->one, i, "one");
4140        diff_debug_filespec(p->two, i, "two");
4141        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4142                p->score, p->status ? p->status : '?',
4143                p->one->rename_used, p->broken_pair);
4144}
4145
4146void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4147{
4148        int i;
4149        if (msg)
4150                fprintf(stderr, "%s\n", msg);
4151        fprintf(stderr, "q->nr = %d\n", q->nr);
4152        for (i = 0; i < q->nr; i++) {
4153                struct diff_filepair *p = q->queue[i];
4154                diff_debug_filepair(p, i);
4155        }
4156}
4157#endif
4158
4159static void diff_resolve_rename_copy(void)
4160{
4161        int i;
4162        struct diff_filepair *p;
4163        struct diff_queue_struct *q = &diff_queued_diff;
4164
4165        diff_debug_queue("resolve-rename-copy", q);
4166
4167        for (i = 0; i < q->nr; i++) {
4168                p = q->queue[i];
4169                p->status = 0; /* undecided */
4170                if (DIFF_PAIR_UNMERGED(p))
4171                        p->status = DIFF_STATUS_UNMERGED;
4172                else if (!DIFF_FILE_VALID(p->one))
4173                        p->status = DIFF_STATUS_ADDED;
4174                else if (!DIFF_FILE_VALID(p->two))
4175                        p->status = DIFF_STATUS_DELETED;
4176                else if (DIFF_PAIR_TYPE_CHANGED(p))
4177                        p->status = DIFF_STATUS_TYPE_CHANGED;
4178
4179                /* from this point on, we are dealing with a pair
4180                 * whose both sides are valid and of the same type, i.e.
4181                 * either in-place edit or rename/copy edit.
4182                 */
4183                else if (DIFF_PAIR_RENAME(p)) {
4184                        /*
4185                         * A rename might have re-connected a broken
4186                         * pair up, causing the pathnames to be the
4187                         * same again. If so, that's not a rename at
4188                         * all, just a modification..
4189                         *
4190                         * Otherwise, see if this source was used for
4191                         * multiple renames, in which case we decrement
4192                         * the count, and call it a copy.
4193                         */
4194                        if (!strcmp(p->one->path, p->two->path))
4195                                p->status = DIFF_STATUS_MODIFIED;
4196                        else if (--p->one->rename_used > 0)
4197                                p->status = DIFF_STATUS_COPIED;
4198                        else
4199                                p->status = DIFF_STATUS_RENAMED;
4200                }
4201                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4202                         p->one->mode != p->two->mode ||
4203                         p->one->dirty_submodule ||
4204                         p->two->dirty_submodule ||
4205                         is_null_sha1(p->one->sha1))
4206                        p->status = DIFF_STATUS_MODIFIED;
4207                else {
4208                        /* This is a "no-change" entry and should not
4209                         * happen anymore, but prepare for broken callers.
4210                         */
4211                        error("feeding unmodified %s to diffcore",
4212                              p->one->path);
4213                        p->status = DIFF_STATUS_UNKNOWN;
4214                }
4215        }
4216        diff_debug_queue("resolve-rename-copy done", q);
4217}
4218
4219static int check_pair_status(struct diff_filepair *p)
4220{
4221        switch (p->status) {
4222        case DIFF_STATUS_UNKNOWN:
4223                return 0;
4224        case 0:
4225                die("internal error in diff-resolve-rename-copy");
4226        default:
4227                return 1;
4228        }
4229}
4230
4231static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4232{
4233        int fmt = opt->output_format;
4234
4235        if (fmt & DIFF_FORMAT_CHECKDIFF)
4236                diff_flush_checkdiff(p, opt);
4237        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4238                diff_flush_raw(p, opt);
4239        else if (fmt & DIFF_FORMAT_NAME) {
4240                const char *name_a, *name_b;
4241                name_a = p->two->path;
4242                name_b = NULL;
4243                strip_prefix(opt->prefix_length, &name_a, &name_b);
4244                write_name_quoted(name_a, opt->file, opt->line_termination);
4245        }
4246}
4247
4248static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4249{
4250        if (fs->mode)
4251                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4252        else
4253                fprintf(file, " %s ", newdelete);
4254        write_name_quoted(fs->path, file, '\n');
4255}
4256
4257
4258static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4259                const char *line_prefix)
4260{
4261        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4262                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4263                        p->two->mode, show_name ? ' ' : '\n');
4264                if (show_name) {
4265                        write_name_quoted(p->two->path, file, '\n');
4266                }
4267        }
4268}
4269
4270static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4271                        const char *line_prefix)
4272{
4273        char *names = pprint_rename(p->one->path, p->two->path);
4274
4275        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4276        free(names);
4277        show_mode_change(file, p, 0, line_prefix);
4278}
4279
4280static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4281{
4282        FILE *file = opt->file;
4283        const char *line_prefix = diff_line_prefix(opt);
4284
4285        switch(p->status) {
4286        case DIFF_STATUS_DELETED:
4287                fputs(line_prefix, file);
4288                show_file_mode_name(file, "delete", p->one);
4289                break;
4290        case DIFF_STATUS_ADDED:
4291                fputs(line_prefix, file);
4292                show_file_mode_name(file, "create", p->two);
4293                break;
4294        case DIFF_STATUS_COPIED:
4295                fputs(line_prefix, file);
4296                show_rename_copy(file, "copy", p, line_prefix);
4297                break;
4298        case DIFF_STATUS_RENAMED:
4299                fputs(line_prefix, file);
4300                show_rename_copy(file, "rename", p, line_prefix);
4301                break;
4302        default:
4303                if (p->score) {
4304                        fprintf(file, "%s rewrite ", line_prefix);
4305                        write_name_quoted(p->two->path, file, ' ');
4306                        fprintf(file, "(%d%%)\n", similarity_index(p));
4307                }
4308                show_mode_change(file, p, !p->score, line_prefix);
4309                break;
4310        }
4311}
4312
4313struct patch_id_t {
4314        git_SHA_CTX *ctx;
4315        int patchlen;
4316};
4317
4318static int remove_space(char *line, int len)
4319{
4320        int i;
4321        char *dst = line;
4322        unsigned char c;
4323
4324        for (i = 0; i < len; i++)
4325                if (!isspace((c = line[i])))
4326                        *dst++ = c;
4327
4328        return dst - line;
4329}
4330
4331static void patch_id_consume(void *priv, char *line, unsigned long len)
4332{
4333        struct patch_id_t *data = priv;
4334        int new_len;
4335
4336        /* Ignore line numbers when computing the SHA1 of the patch */
4337        if (starts_with(line, "@@ -"))
4338                return;
4339
4340        new_len = remove_space(line, len);
4341
4342        git_SHA1_Update(data->ctx, line, new_len);
4343        data->patchlen += new_len;
4344}
4345
4346/* returns 0 upon success, and writes result into sha1 */
4347static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4348{
4349        struct diff_queue_struct *q = &diff_queued_diff;
4350        int i;
4351        git_SHA_CTX ctx;
4352        struct patch_id_t data;
4353        char buffer[PATH_MAX * 4 + 20];
4354
4355        git_SHA1_Init(&ctx);
4356        memset(&data, 0, sizeof(struct patch_id_t));
4357        data.ctx = &ctx;
4358
4359        for (i = 0; i < q->nr; i++) {
4360                xpparam_t xpp;
4361                xdemitconf_t xecfg;
4362                mmfile_t mf1, mf2;
4363                struct diff_filepair *p = q->queue[i];
4364                int len1, len2;
4365
4366                memset(&xpp, 0, sizeof(xpp));
4367                memset(&xecfg, 0, sizeof(xecfg));
4368                if (p->status == 0)
4369                        return error("internal diff status error");
4370                if (p->status == DIFF_STATUS_UNKNOWN)
4371                        continue;
4372                if (diff_unmodified_pair(p))
4373                        continue;
4374                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4375                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4376                        continue;
4377                if (DIFF_PAIR_UNMERGED(p))
4378                        continue;
4379
4380                diff_fill_sha1_info(p->one);
4381                diff_fill_sha1_info(p->two);
4382                if (fill_mmfile(&mf1, p->one) < 0 ||
4383                                fill_mmfile(&mf2, p->two) < 0)
4384                        return error("unable to read files to diff");
4385
4386                len1 = remove_space(p->one->path, strlen(p->one->path));
4387                len2 = remove_space(p->two->path, strlen(p->two->path));
4388                if (p->one->mode == 0)
4389                        len1 = snprintf(buffer, sizeof(buffer),
4390                                        "diff--gita/%.*sb/%.*s"
4391                                        "newfilemode%06o"
4392                                        "---/dev/null"
4393                                        "+++b/%.*s",
4394                                        len1, p->one->path,
4395                                        len2, p->two->path,
4396                                        p->two->mode,
4397                                        len2, p->two->path);
4398                else if (p->two->mode == 0)
4399                        len1 = snprintf(buffer, sizeof(buffer),
4400                                        "diff--gita/%.*sb/%.*s"
4401                                        "deletedfilemode%06o"
4402                                        "---a/%.*s"
4403                                        "+++/dev/null",
4404                                        len1, p->one->path,
4405                                        len2, p->two->path,
4406                                        p->one->mode,
4407                                        len1, p->one->path);
4408                else
4409                        len1 = snprintf(buffer, sizeof(buffer),
4410                                        "diff--gita/%.*sb/%.*s"
4411                                        "---a/%.*s"
4412                                        "+++b/%.*s",
4413                                        len1, p->one->path,
4414                                        len2, p->two->path,
4415                                        len1, p->one->path,
4416                                        len2, p->two->path);
4417                git_SHA1_Update(&ctx, buffer, len1);
4418
4419                if (diff_filespec_is_binary(p->one) ||
4420                    diff_filespec_is_binary(p->two)) {
4421                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4422                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4423                        continue;
4424                }
4425
4426                xpp.flags = 0;
4427                xecfg.ctxlen = 3;
4428                xecfg.flags = 0;
4429                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4430                              &xpp, &xecfg);
4431        }
4432
4433        git_SHA1_Final(sha1, &ctx);
4434        return 0;
4435}
4436
4437int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4438{
4439        struct diff_queue_struct *q = &diff_queued_diff;
4440        int i;
4441        int result = diff_get_patch_id(options, sha1);
4442
4443        for (i = 0; i < q->nr; i++)
4444                diff_free_filepair(q->queue[i]);
4445
4446        free(q->queue);
4447        DIFF_QUEUE_CLEAR(q);
4448
4449        return result;
4450}
4451
4452static int is_summary_empty(const struct diff_queue_struct *q)
4453{
4454        int i;
4455
4456        for (i = 0; i < q->nr; i++) {
4457                const struct diff_filepair *p = q->queue[i];
4458
4459                switch (p->status) {
4460                case DIFF_STATUS_DELETED:
4461                case DIFF_STATUS_ADDED:
4462                case DIFF_STATUS_COPIED:
4463                case DIFF_STATUS_RENAMED:
4464                        return 0;
4465                default:
4466                        if (p->score)
4467                                return 0;
4468                        if (p->one->mode && p->two->mode &&
4469                            p->one->mode != p->two->mode)
4470                                return 0;
4471                        break;
4472                }
4473        }
4474        return 1;
4475}
4476
4477static const char rename_limit_warning[] =
4478"inexact rename detection was skipped due to too many files.";
4479
4480static const char degrade_cc_to_c_warning[] =
4481"only found copies from modified paths due to too many files.";
4482
4483static const char rename_limit_advice[] =
4484"you may want to set your %s variable to at least "
4485"%d and retry the command.";
4486
4487void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4488{
4489        if (degraded_cc)
4490                warning(degrade_cc_to_c_warning);
4491        else if (needed)
4492                warning(rename_limit_warning);
4493        else
4494                return;
4495        if (0 < needed && needed < 32767)
4496                warning(rename_limit_advice, varname, needed);
4497}
4498
4499void diff_flush(struct diff_options *options)
4500{
4501        struct diff_queue_struct *q = &diff_queued_diff;
4502        int i, output_format = options->output_format;
4503        int separator = 0;
4504        int dirstat_by_line = 0;
4505
4506        /*
4507         * Order: raw, stat, summary, patch
4508         * or:    name/name-status/checkdiff (other bits clear)
4509         */
4510        if (!q->nr)
4511                goto free_queue;
4512
4513        if (output_format & (DIFF_FORMAT_RAW |
4514                             DIFF_FORMAT_NAME |
4515                             DIFF_FORMAT_NAME_STATUS |
4516                             DIFF_FORMAT_CHECKDIFF)) {
4517                for (i = 0; i < q->nr; i++) {
4518                        struct diff_filepair *p = q->queue[i];
4519                        if (check_pair_status(p))
4520                                flush_one_pair(p, options);
4521                }
4522                separator++;
4523        }
4524
4525        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4526                dirstat_by_line = 1;
4527
4528        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4529            dirstat_by_line) {
4530                struct diffstat_t diffstat;
4531
4532                memset(&diffstat, 0, sizeof(struct diffstat_t));
4533                for (i = 0; i < q->nr; i++) {
4534                        struct diff_filepair *p = q->queue[i];
4535                        if (check_pair_status(p))
4536                                diff_flush_stat(p, options, &diffstat);
4537                }
4538                if (output_format & DIFF_FORMAT_NUMSTAT)
4539                        show_numstat(&diffstat, options);
4540                if (output_format & DIFF_FORMAT_DIFFSTAT)
4541                        show_stats(&diffstat, options);
4542                if (output_format & DIFF_FORMAT_SHORTSTAT)
4543                        show_shortstats(&diffstat, options);
4544                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4545                        show_dirstat_by_line(&diffstat, options);
4546                free_diffstat_info(&diffstat);
4547                separator++;
4548        }
4549        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4550                show_dirstat(options);
4551
4552        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4553                for (i = 0; i < q->nr; i++) {
4554                        diff_summary(options, q->queue[i]);
4555                }
4556                separator++;
4557        }
4558
4559        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4560            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4561            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4562                /*
4563                 * run diff_flush_patch for the exit status. setting
4564                 * options->file to /dev/null should be safe, because we
4565                 * aren't supposed to produce any output anyway.
4566                 */
4567                if (options->close_file)
4568                        fclose(options->file);
4569                options->file = fopen("/dev/null", "w");
4570                if (!options->file)
4571                        die_errno("Could not open /dev/null");
4572                options->close_file = 1;
4573                for (i = 0; i < q->nr; i++) {
4574                        struct diff_filepair *p = q->queue[i];
4575                        if (check_pair_status(p))
4576                                diff_flush_patch(p, options);
4577                        if (options->found_changes)
4578                                break;
4579                }
4580        }
4581
4582        if (output_format & DIFF_FORMAT_PATCH) {
4583                if (separator) {
4584                        fprintf(options->file, "%s%c",
4585                                diff_line_prefix(options),
4586                                options->line_termination);
4587                        if (options->stat_sep) {
4588                                /* attach patch instead of inline */
4589                                fputs(options->stat_sep, options->file);
4590                        }
4591                }
4592
4593                for (i = 0; i < q->nr; i++) {
4594                        struct diff_filepair *p = q->queue[i];
4595                        if (check_pair_status(p))
4596                                diff_flush_patch(p, options);
4597                }
4598        }
4599
4600        if (output_format & DIFF_FORMAT_CALLBACK)
4601                options->format_callback(q, options, options->format_callback_data);
4602
4603        for (i = 0; i < q->nr; i++)
4604                diff_free_filepair(q->queue[i]);
4605free_queue:
4606        free(q->queue);
4607        DIFF_QUEUE_CLEAR(q);
4608        if (options->close_file)
4609                fclose(options->file);
4610
4611        /*
4612         * Report the content-level differences with HAS_CHANGES;
4613         * diff_addremove/diff_change does not set the bit when
4614         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4615         */
4616        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4617                if (options->found_changes)
4618                        DIFF_OPT_SET(options, HAS_CHANGES);
4619                else
4620                        DIFF_OPT_CLR(options, HAS_CHANGES);
4621        }
4622}
4623
4624static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4625{
4626        return (((p->status == DIFF_STATUS_MODIFIED) &&
4627                 ((p->score &&
4628                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4629                  (!p->score &&
4630                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4631                ((p->status != DIFF_STATUS_MODIFIED) &&
4632                 filter_bit_tst(p->status, options)));
4633}
4634
4635static void diffcore_apply_filter(struct diff_options *options)
4636{
4637        int i;
4638        struct diff_queue_struct *q = &diff_queued_diff;
4639        struct diff_queue_struct outq;
4640
4641        DIFF_QUEUE_CLEAR(&outq);
4642
4643        if (!options->filter)
4644                return;
4645
4646        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4647                int found;
4648                for (i = found = 0; !found && i < q->nr; i++) {
4649                        if (match_filter(options, q->queue[i]))
4650                                found++;
4651                }
4652                if (found)
4653                        return;
4654
4655                /* otherwise we will clear the whole queue
4656                 * by copying the empty outq at the end of this
4657                 * function, but first clear the current entries
4658                 * in the queue.
4659                 */
4660                for (i = 0; i < q->nr; i++)
4661                        diff_free_filepair(q->queue[i]);
4662        }
4663        else {
4664                /* Only the matching ones */
4665                for (i = 0; i < q->nr; i++) {
4666                        struct diff_filepair *p = q->queue[i];
4667                        if (match_filter(options, p))
4668                                diff_q(&outq, p);
4669                        else
4670                                diff_free_filepair(p);
4671                }
4672        }
4673        free(q->queue);
4674        *q = outq;
4675}
4676
4677/* Check whether two filespecs with the same mode and size are identical */
4678static int diff_filespec_is_identical(struct diff_filespec *one,
4679                                      struct diff_filespec *two)
4680{
4681        if (S_ISGITLINK(one->mode))
4682                return 0;
4683        if (diff_populate_filespec(one, 0))
4684                return 0;
4685        if (diff_populate_filespec(two, 0))
4686                return 0;
4687        return !memcmp(one->data, two->data, one->size);
4688}
4689
4690static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4691{
4692        if (p->done_skip_stat_unmatch)
4693                return p->skip_stat_unmatch_result;
4694
4695        p->done_skip_stat_unmatch = 1;
4696        p->skip_stat_unmatch_result = 0;
4697        /*
4698         * 1. Entries that come from stat info dirtiness
4699         *    always have both sides (iow, not create/delete),
4700         *    one side of the object name is unknown, with
4701         *    the same mode and size.  Keep the ones that
4702         *    do not match these criteria.  They have real
4703         *    differences.
4704         *
4705         * 2. At this point, the file is known to be modified,
4706         *    with the same mode and size, and the object
4707         *    name of one side is unknown.  Need to inspect
4708         *    the identical contents.
4709         */
4710        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4711            !DIFF_FILE_VALID(p->two) ||
4712            (p->one->sha1_valid && p->two->sha1_valid) ||
4713            (p->one->mode != p->two->mode) ||
4714            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4715            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4716            (p->one->size != p->two->size) ||
4717            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4718                p->skip_stat_unmatch_result = 1;
4719        return p->skip_stat_unmatch_result;
4720}
4721
4722static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4723{
4724        int i;
4725        struct diff_queue_struct *q = &diff_queued_diff;
4726        struct diff_queue_struct outq;
4727        DIFF_QUEUE_CLEAR(&outq);
4728
4729        for (i = 0; i < q->nr; i++) {
4730                struct diff_filepair *p = q->queue[i];
4731
4732                if (diff_filespec_check_stat_unmatch(p))
4733                        diff_q(&outq, p);
4734                else {
4735                        /*
4736                         * The caller can subtract 1 from skip_stat_unmatch
4737                         * to determine how many paths were dirty only
4738                         * due to stat info mismatch.
4739                         */
4740                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4741                                diffopt->skip_stat_unmatch++;
4742                        diff_free_filepair(p);
4743                }
4744        }
4745        free(q->queue);
4746        *q = outq;
4747}
4748
4749static int diffnamecmp(const void *a_, const void *b_)
4750{
4751        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4752        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4753        const char *name_a, *name_b;
4754
4755        name_a = a->one ? a->one->path : a->two->path;
4756        name_b = b->one ? b->one->path : b->two->path;
4757        return strcmp(name_a, name_b);
4758}
4759
4760void diffcore_fix_diff_index(struct diff_options *options)
4761{
4762        struct diff_queue_struct *q = &diff_queued_diff;
4763        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4764}
4765
4766void diffcore_std(struct diff_options *options)
4767{
4768        /* NOTE please keep the following in sync with diff_tree_combined() */
4769        if (options->skip_stat_unmatch)
4770                diffcore_skip_stat_unmatch(options);
4771        if (!options->found_follow) {
4772                /* See try_to_follow_renames() in tree-diff.c */
4773                if (options->break_opt != -1)
4774                        diffcore_break(options->break_opt);
4775                if (options->detect_rename)
4776                        diffcore_rename(options);
4777                if (options->break_opt != -1)
4778                        diffcore_merge_broken();
4779        }
4780        if (options->pickaxe)
4781                diffcore_pickaxe(options);
4782        if (options->orderfile)
4783                diffcore_order(options->orderfile);
4784        if (!options->found_follow)
4785                /* See try_to_follow_renames() in tree-diff.c */
4786                diff_resolve_rename_copy();
4787        diffcore_apply_filter(options);
4788
4789        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4790                DIFF_OPT_SET(options, HAS_CHANGES);
4791        else
4792                DIFF_OPT_CLR(options, HAS_CHANGES);
4793
4794        options->found_follow = 0;
4795}
4796
4797int diff_result_code(struct diff_options *opt, int status)
4798{
4799        int result = 0;
4800
4801        diff_warn_rename_limit("diff.renameLimit",
4802                               opt->needed_rename_limit,
4803                               opt->degraded_cc_to_c);
4804        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4805            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4806                return status;
4807        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4808            DIFF_OPT_TST(opt, HAS_CHANGES))
4809                result |= 01;
4810        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4811            DIFF_OPT_TST(opt, CHECK_FAILED))
4812                result |= 02;
4813        return result;
4814}
4815
4816int diff_can_quit_early(struct diff_options *opt)
4817{
4818        return (DIFF_OPT_TST(opt, QUICK) &&
4819                !opt->filter &&
4820                DIFF_OPT_TST(opt, HAS_CHANGES));
4821}
4822
4823/*
4824 * Shall changes to this submodule be ignored?
4825 *
4826 * Submodule changes can be configured to be ignored separately for each path,
4827 * but that configuration can be overridden from the command line.
4828 */
4829static int is_submodule_ignored(const char *path, struct diff_options *options)
4830{
4831        int ignored = 0;
4832        unsigned orig_flags = options->flags;
4833        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4834                set_diffopt_flags_from_submodule_config(options, path);
4835        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4836                ignored = 1;
4837        options->flags = orig_flags;
4838        return ignored;
4839}
4840
4841void diff_addremove(struct diff_options *options,
4842                    int addremove, unsigned mode,
4843                    const unsigned char *sha1,
4844                    int sha1_valid,
4845                    const char *concatpath, unsigned dirty_submodule)
4846{
4847        struct diff_filespec *one, *two;
4848
4849        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4850                return;
4851
4852        /* This may look odd, but it is a preparation for
4853         * feeding "there are unchanged files which should
4854         * not produce diffs, but when you are doing copy
4855         * detection you would need them, so here they are"
4856         * entries to the diff-core.  They will be prefixed
4857         * with something like '=' or '*' (I haven't decided
4858         * which but should not make any difference).
4859         * Feeding the same new and old to diff_change()
4860         * also has the same effect.
4861         * Before the final output happens, they are pruned after
4862         * merged into rename/copy pairs as appropriate.
4863         */
4864        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4865                addremove = (addremove == '+' ? '-' :
4866                             addremove == '-' ? '+' : addremove);
4867
4868        if (options->prefix &&
4869            strncmp(concatpath, options->prefix, options->prefix_length))
4870                return;
4871
4872        one = alloc_filespec(concatpath);
4873        two = alloc_filespec(concatpath);
4874
4875        if (addremove != '+')
4876                fill_filespec(one, sha1, sha1_valid, mode);
4877        if (addremove != '-') {
4878                fill_filespec(two, sha1, sha1_valid, mode);
4879                two->dirty_submodule = dirty_submodule;
4880        }
4881
4882        diff_queue(&diff_queued_diff, one, two);
4883        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4884                DIFF_OPT_SET(options, HAS_CHANGES);
4885}
4886
4887void diff_change(struct diff_options *options,
4888                 unsigned old_mode, unsigned new_mode,
4889                 const unsigned char *old_sha1,
4890                 const unsigned char *new_sha1,
4891                 int old_sha1_valid, int new_sha1_valid,
4892                 const char *concatpath,
4893                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4894{
4895        struct diff_filespec *one, *two;
4896        struct diff_filepair *p;
4897
4898        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4899            is_submodule_ignored(concatpath, options))
4900                return;
4901
4902        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4903                unsigned tmp;
4904                const unsigned char *tmp_c;
4905                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4906                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4907                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4908                        new_sha1_valid = tmp;
4909                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4910                        new_dirty_submodule = tmp;
4911        }
4912
4913        if (options->prefix &&
4914            strncmp(concatpath, options->prefix, options->prefix_length))
4915                return;
4916
4917        one = alloc_filespec(concatpath);
4918        two = alloc_filespec(concatpath);
4919        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4920        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4921        one->dirty_submodule = old_dirty_submodule;
4922        two->dirty_submodule = new_dirty_submodule;
4923        p = diff_queue(&diff_queued_diff, one, two);
4924
4925        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4926                return;
4927
4928        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
4929            !diff_filespec_check_stat_unmatch(p))
4930                return;
4931
4932        DIFF_OPT_SET(options, HAS_CHANGES);
4933}
4934
4935struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4936{
4937        struct diff_filepair *pair;
4938        struct diff_filespec *one, *two;
4939
4940        if (options->prefix &&
4941            strncmp(path, options->prefix, options->prefix_length))
4942                return NULL;
4943
4944        one = alloc_filespec(path);
4945        two = alloc_filespec(path);
4946        pair = diff_queue(&diff_queued_diff, one, two);
4947        pair->is_unmerged = 1;
4948        return pair;
4949}
4950
4951static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4952                size_t *outsize)
4953{
4954        struct diff_tempfile *temp;
4955        const char *argv[3];
4956        const char **arg = argv;
4957        struct child_process child = CHILD_PROCESS_INIT;
4958        struct strbuf buf = STRBUF_INIT;
4959        int err = 0;
4960
4961        temp = prepare_temp_file(spec->path, spec);
4962        *arg++ = pgm;
4963        *arg++ = temp->name;
4964        *arg = NULL;
4965
4966        child.use_shell = 1;
4967        child.argv = argv;
4968        child.out = -1;
4969        if (start_command(&child)) {
4970                remove_tempfile();
4971                return NULL;
4972        }
4973
4974        if (strbuf_read(&buf, child.out, 0) < 0)
4975                err = error("error reading from textconv command '%s'", pgm);
4976        close(child.out);
4977
4978        if (finish_command(&child) || err) {
4979                strbuf_release(&buf);
4980                remove_tempfile();
4981                return NULL;
4982        }
4983        remove_tempfile();
4984
4985        return strbuf_detach(&buf, outsize);
4986}
4987
4988size_t fill_textconv(struct userdiff_driver *driver,
4989                     struct diff_filespec *df,
4990                     char **outbuf)
4991{
4992        size_t size;
4993
4994        if (!driver || !driver->textconv) {
4995                if (!DIFF_FILE_VALID(df)) {
4996                        *outbuf = "";
4997                        return 0;
4998                }
4999                if (diff_populate_filespec(df, 0))
5000                        die("unable to read files to diff");
5001                *outbuf = df->data;
5002                return df->size;
5003        }
5004
5005        if (driver->textconv_cache && df->sha1_valid) {
5006                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5007                                          &size);
5008                if (*outbuf)
5009                        return size;
5010        }
5011
5012        *outbuf = run_textconv(driver->textconv, df, &size);
5013        if (!*outbuf)
5014                die("unable to read files to diff");
5015
5016        if (driver->textconv_cache && df->sha1_valid) {
5017                /* ignore errors, as we might be in a readonly repository */
5018                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5019                                size);
5020                /*
5021                 * we could save up changes and flush them all at the end,
5022                 * but we would need an extra call after all diffing is done.
5023                 * Since generating a cache entry is the slow path anyway,
5024                 * this extra overhead probably isn't a big deal.
5025                 */
5026                notes_cache_write(driver->textconv_cache);
5027        }
5028
5029        return size;
5030}
5031
5032void setup_diff_pager(struct diff_options *opt)
5033{
5034        /*
5035         * If the user asked for our exit code, then either they want --quiet
5036         * or --exit-code. We should definitely not bother with a pager in the
5037         * former case, as we will generate no output. Since we still properly
5038         * report our exit code even when a pager is run, we _could_ run a
5039         * pager with --exit-code. But since we have not done so historically,
5040         * and because it is easy to find people oneline advising "git diff
5041         * --exit-code" in hooks and other scripts, we do not do so.
5042         */
5043        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5044            check_pager_config("diff") != 0)
5045                setup_pager();
5046}