diff.con commit Merge branch 'nd/large-blobs' (bedd3b4)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18#include "string-list.h"
  19#include "argv-array.h"
  20
  21#ifdef NO_FAST_WORKING_DIRECTORY
  22#define FAST_WORKING_DIRECTORY 0
  23#else
  24#define FAST_WORKING_DIRECTORY 1
  25#endif
  26
  27static int diff_detect_rename_default;
  28static int diff_rename_limit_default = 400;
  29static int diff_suppress_blank_empty;
  30static int diff_use_color_default = -1;
  31static int diff_context_default = 3;
  32static const char *diff_word_regex_cfg;
  33static const char *external_diff_cmd_cfg;
  34static const char *diff_order_file_cfg;
  35int diff_auto_refresh_index = 1;
  36static int diff_mnemonic_prefix;
  37static int diff_no_prefix;
  38static int diff_stat_graph_width;
  39static int diff_dirstat_permille_default = 30;
  40static struct diff_options default_diff_options;
  41static long diff_algorithm;
  42
  43static char diff_colors[][COLOR_MAXLEN] = {
  44        GIT_COLOR_RESET,
  45        GIT_COLOR_NORMAL,       /* PLAIN */
  46        GIT_COLOR_BOLD,         /* METAINFO */
  47        GIT_COLOR_CYAN,         /* FRAGINFO */
  48        GIT_COLOR_RED,          /* OLD */
  49        GIT_COLOR_GREEN,        /* NEW */
  50        GIT_COLOR_YELLOW,       /* COMMIT */
  51        GIT_COLOR_BG_RED,       /* WHITESPACE */
  52        GIT_COLOR_NORMAL,       /* FUNCINFO */
  53};
  54
  55static int parse_diff_color_slot(const char *var)
  56{
  57        if (!strcasecmp(var, "plain"))
  58                return DIFF_PLAIN;
  59        if (!strcasecmp(var, "meta"))
  60                return DIFF_METAINFO;
  61        if (!strcasecmp(var, "frag"))
  62                return DIFF_FRAGINFO;
  63        if (!strcasecmp(var, "old"))
  64                return DIFF_FILE_OLD;
  65        if (!strcasecmp(var, "new"))
  66                return DIFF_FILE_NEW;
  67        if (!strcasecmp(var, "commit"))
  68                return DIFF_COMMIT;
  69        if (!strcasecmp(var, "whitespace"))
  70                return DIFF_WHITESPACE;
  71        if (!strcasecmp(var, "func"))
  72                return DIFF_FUNCINFO;
  73        return -1;
  74}
  75
  76static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  77                                struct strbuf *errmsg)
  78{
  79        char *params_copy = xstrdup(params_string);
  80        struct string_list params = STRING_LIST_INIT_NODUP;
  81        int ret = 0;
  82        int i;
  83
  84        if (*params_copy)
  85                string_list_split_in_place(&params, params_copy, ',', -1);
  86        for (i = 0; i < params.nr; i++) {
  87                const char *p = params.items[i].string;
  88                if (!strcmp(p, "changes")) {
  89                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  90                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  91                } else if (!strcmp(p, "lines")) {
  92                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  93                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  94                } else if (!strcmp(p, "files")) {
  95                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  96                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  97                } else if (!strcmp(p, "noncumulative")) {
  98                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  99                } else if (!strcmp(p, "cumulative")) {
 100                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 101                } else if (isdigit(*p)) {
 102                        char *end;
 103                        int permille = strtoul(p, &end, 10) * 10;
 104                        if (*end == '.' && isdigit(*++end)) {
 105                                /* only use first digit */
 106                                permille += *end - '0';
 107                                /* .. and ignore any further digits */
 108                                while (isdigit(*++end))
 109                                        ; /* nothing */
 110                        }
 111                        if (!*end)
 112                                options->dirstat_permille = permille;
 113                        else {
 114                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 115                                            p);
 116                                ret++;
 117                        }
 118                } else {
 119                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 120                        ret++;
 121                }
 122
 123        }
 124        string_list_clear(&params, 0);
 125        free(params_copy);
 126        return ret;
 127}
 128
 129static int parse_submodule_params(struct diff_options *options, const char *value)
 130{
 131        if (!strcmp(value, "log"))
 132                DIFF_OPT_SET(options, SUBMODULE_LOG);
 133        else if (!strcmp(value, "short"))
 134                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 135        else
 136                return -1;
 137        return 0;
 138}
 139
 140static int git_config_rename(const char *var, const char *value)
 141{
 142        if (!value)
 143                return DIFF_DETECT_RENAME;
 144        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 145                return  DIFF_DETECT_COPY;
 146        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 147}
 148
 149long parse_algorithm_value(const char *value)
 150{
 151        if (!value)
 152                return -1;
 153        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 154                return 0;
 155        else if (!strcasecmp(value, "minimal"))
 156                return XDF_NEED_MINIMAL;
 157        else if (!strcasecmp(value, "patience"))
 158                return XDF_PATIENCE_DIFF;
 159        else if (!strcasecmp(value, "histogram"))
 160                return XDF_HISTOGRAM_DIFF;
 161        return -1;
 162}
 163
 164/*
 165 * These are to give UI layer defaults.
 166 * The core-level commands such as git-diff-files should
 167 * never be affected by the setting of diff.renames
 168 * the user happens to have in the configuration file.
 169 */
 170int git_diff_ui_config(const char *var, const char *value, void *cb)
 171{
 172        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 173                diff_use_color_default = git_config_colorbool(var, value);
 174                return 0;
 175        }
 176        if (!strcmp(var, "diff.context")) {
 177                diff_context_default = git_config_int(var, value);
 178                if (diff_context_default < 0)
 179                        return -1;
 180                return 0;
 181        }
 182        if (!strcmp(var, "diff.renames")) {
 183                diff_detect_rename_default = git_config_rename(var, value);
 184                return 0;
 185        }
 186        if (!strcmp(var, "diff.autorefreshindex")) {
 187                diff_auto_refresh_index = git_config_bool(var, value);
 188                return 0;
 189        }
 190        if (!strcmp(var, "diff.mnemonicprefix")) {
 191                diff_mnemonic_prefix = git_config_bool(var, value);
 192                return 0;
 193        }
 194        if (!strcmp(var, "diff.noprefix")) {
 195                diff_no_prefix = git_config_bool(var, value);
 196                return 0;
 197        }
 198        if (!strcmp(var, "diff.statgraphwidth")) {
 199                diff_stat_graph_width = git_config_int(var, value);
 200                return 0;
 201        }
 202        if (!strcmp(var, "diff.external"))
 203                return git_config_string(&external_diff_cmd_cfg, var, value);
 204        if (!strcmp(var, "diff.wordregex"))
 205                return git_config_string(&diff_word_regex_cfg, var, value);
 206        if (!strcmp(var, "diff.orderfile"))
 207                return git_config_pathname(&diff_order_file_cfg, var, value);
 208
 209        if (!strcmp(var, "diff.ignoresubmodules"))
 210                handle_ignore_submodules_arg(&default_diff_options, value);
 211
 212        if (!strcmp(var, "diff.submodule")) {
 213                if (parse_submodule_params(&default_diff_options, value))
 214                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 215                                value);
 216                return 0;
 217        }
 218
 219        if (!strcmp(var, "diff.algorithm")) {
 220                diff_algorithm = parse_algorithm_value(value);
 221                if (diff_algorithm < 0)
 222                        return -1;
 223                return 0;
 224        }
 225
 226        if (git_color_config(var, value, cb) < 0)
 227                return -1;
 228
 229        return git_diff_basic_config(var, value, cb);
 230}
 231
 232int git_diff_basic_config(const char *var, const char *value, void *cb)
 233{
 234        const char *name;
 235
 236        if (!strcmp(var, "diff.renamelimit")) {
 237                diff_rename_limit_default = git_config_int(var, value);
 238                return 0;
 239        }
 240
 241        if (userdiff_config(var, value) < 0)
 242                return -1;
 243
 244        if (skip_prefix(var, "diff.color.", &name) ||
 245            skip_prefix(var, "color.diff.", &name)) {
 246                int slot = parse_diff_color_slot(name);
 247                if (slot < 0)
 248                        return 0;
 249                if (!value)
 250                        return config_error_nonbool(var);
 251                color_parse(value, var, diff_colors[slot]);
 252                return 0;
 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        memset(&stream, 0, sizeof(stream));
2098        git_deflate_init(&stream, zlib_compression_level);
2099        bound = git_deflate_bound(&stream, size);
2100        deflated = xmalloc(bound);
2101        stream.next_out = deflated;
2102        stream.avail_out = bound;
2103
2104        stream.next_in = (unsigned char *)data;
2105        stream.avail_in = size;
2106        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2107                ; /* nothing */
2108        git_deflate_end(&stream);
2109        *result_size = stream.total_out;
2110        return deflated;
2111}
2112
2113static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2114                                  const char *prefix)
2115{
2116        void *cp;
2117        void *delta;
2118        void *deflated;
2119        void *data;
2120        unsigned long orig_size;
2121        unsigned long delta_size;
2122        unsigned long deflate_size;
2123        unsigned long data_size;
2124
2125        /* We could do deflated delta, or we could do just deflated two,
2126         * whichever is smaller.
2127         */
2128        delta = NULL;
2129        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2130        if (one->size && two->size) {
2131                delta = diff_delta(one->ptr, one->size,
2132                                   two->ptr, two->size,
2133                                   &delta_size, deflate_size);
2134                if (delta) {
2135                        void *to_free = delta;
2136                        orig_size = delta_size;
2137                        delta = deflate_it(delta, delta_size, &delta_size);
2138                        free(to_free);
2139                }
2140        }
2141
2142        if (delta && delta_size < deflate_size) {
2143                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2144                free(deflated);
2145                data = delta;
2146                data_size = delta_size;
2147        }
2148        else {
2149                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2150                free(delta);
2151                data = deflated;
2152                data_size = deflate_size;
2153        }
2154
2155        /* emit data encoded in base85 */
2156        cp = data;
2157        while (data_size) {
2158                int bytes = (52 < data_size) ? 52 : data_size;
2159                char line[70];
2160                data_size -= bytes;
2161                if (bytes <= 26)
2162                        line[0] = bytes + 'A' - 1;
2163                else
2164                        line[0] = bytes - 26 + 'a' - 1;
2165                encode_85(line + 1, cp, bytes);
2166                cp = (char *) cp + bytes;
2167                fprintf(file, "%s", prefix);
2168                fputs(line, file);
2169                fputc('\n', file);
2170        }
2171        fprintf(file, "%s\n", prefix);
2172        free(data);
2173}
2174
2175static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2176                             const char *prefix)
2177{
2178        fprintf(file, "%sGIT binary patch\n", prefix);
2179        emit_binary_diff_body(file, one, two, prefix);
2180        emit_binary_diff_body(file, two, one, prefix);
2181}
2182
2183int diff_filespec_is_binary(struct diff_filespec *one)
2184{
2185        if (one->is_binary == -1) {
2186                diff_filespec_load_driver(one);
2187                if (one->driver->binary != -1)
2188                        one->is_binary = one->driver->binary;
2189                else {
2190                        if (!one->data && DIFF_FILE_VALID(one))
2191                                diff_populate_filespec(one, CHECK_BINARY);
2192                        if (one->is_binary == -1 && one->data)
2193                                one->is_binary = buffer_is_binary(one->data,
2194                                                one->size);
2195                        if (one->is_binary == -1)
2196                                one->is_binary = 0;
2197                }
2198        }
2199        return one->is_binary;
2200}
2201
2202static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2203{
2204        diff_filespec_load_driver(one);
2205        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2206}
2207
2208void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2209{
2210        if (!options->a_prefix)
2211                options->a_prefix = a;
2212        if (!options->b_prefix)
2213                options->b_prefix = b;
2214}
2215
2216struct userdiff_driver *get_textconv(struct diff_filespec *one)
2217{
2218        if (!DIFF_FILE_VALID(one))
2219                return NULL;
2220
2221        diff_filespec_load_driver(one);
2222        return userdiff_get_textconv(one->driver);
2223}
2224
2225static void builtin_diff(const char *name_a,
2226                         const char *name_b,
2227                         struct diff_filespec *one,
2228                         struct diff_filespec *two,
2229                         const char *xfrm_msg,
2230                         int must_show_header,
2231                         struct diff_options *o,
2232                         int complete_rewrite)
2233{
2234        mmfile_t mf1, mf2;
2235        const char *lbl[2];
2236        char *a_one, *b_two;
2237        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2238        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2239        const char *a_prefix, *b_prefix;
2240        struct userdiff_driver *textconv_one = NULL;
2241        struct userdiff_driver *textconv_two = NULL;
2242        struct strbuf header = STRBUF_INIT;
2243        const char *line_prefix = diff_line_prefix(o);
2244
2245        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2246                        (!one->mode || S_ISGITLINK(one->mode)) &&
2247                        (!two->mode || S_ISGITLINK(two->mode))) {
2248                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2249                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2250                show_submodule_summary(o->file, one->path ? one->path : two->path,
2251                                line_prefix,
2252                                one->sha1, two->sha1, two->dirty_submodule,
2253                                meta, del, add, reset);
2254                return;
2255        }
2256
2257        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2258                textconv_one = get_textconv(one);
2259                textconv_two = get_textconv(two);
2260        }
2261
2262        diff_set_mnemonic_prefix(o, "a/", "b/");
2263        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2264                a_prefix = o->b_prefix;
2265                b_prefix = o->a_prefix;
2266        } else {
2267                a_prefix = o->a_prefix;
2268                b_prefix = o->b_prefix;
2269        }
2270
2271        /* Never use a non-valid filename anywhere if at all possible */
2272        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2273        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2274
2275        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2276        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2277        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2278        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2279        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2280        if (lbl[0][0] == '/') {
2281                /* /dev/null */
2282                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2283                if (xfrm_msg)
2284                        strbuf_addstr(&header, xfrm_msg);
2285                must_show_header = 1;
2286        }
2287        else if (lbl[1][0] == '/') {
2288                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2289                if (xfrm_msg)
2290                        strbuf_addstr(&header, xfrm_msg);
2291                must_show_header = 1;
2292        }
2293        else {
2294                if (one->mode != two->mode) {
2295                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2296                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2297                        must_show_header = 1;
2298                }
2299                if (xfrm_msg)
2300                        strbuf_addstr(&header, xfrm_msg);
2301
2302                /*
2303                 * we do not run diff between different kind
2304                 * of objects.
2305                 */
2306                if ((one->mode ^ two->mode) & S_IFMT)
2307                        goto free_ab_and_return;
2308                if (complete_rewrite &&
2309                    (textconv_one || !diff_filespec_is_binary(one)) &&
2310                    (textconv_two || !diff_filespec_is_binary(two))) {
2311                        fprintf(o->file, "%s", header.buf);
2312                        strbuf_reset(&header);
2313                        emit_rewrite_diff(name_a, name_b, one, two,
2314                                                textconv_one, textconv_two, o);
2315                        o->found_changes = 1;
2316                        goto free_ab_and_return;
2317                }
2318        }
2319
2320        if (o->irreversible_delete && lbl[1][0] == '/') {
2321                fprintf(o->file, "%s", header.buf);
2322                strbuf_reset(&header);
2323                goto free_ab_and_return;
2324        } else if (!DIFF_OPT_TST(o, TEXT) &&
2325            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2326              (!textconv_two && diff_filespec_is_binary(two)) )) {
2327                if (!one->data && !two->data &&
2328                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2329                    !DIFF_OPT_TST(o, BINARY)) {
2330                        if (!hashcmp(one->sha1, two->sha1)) {
2331                                if (must_show_header)
2332                                        fprintf(o->file, "%s", header.buf);
2333                                goto free_ab_and_return;
2334                        }
2335                        fprintf(o->file, "%s", header.buf);
2336                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2337                                line_prefix, lbl[0], lbl[1]);
2338                        goto free_ab_and_return;
2339                }
2340                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2341                        die("unable to read files to diff");
2342                /* Quite common confusing case */
2343                if (mf1.size == mf2.size &&
2344                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2345                        if (must_show_header)
2346                                fprintf(o->file, "%s", header.buf);
2347                        goto free_ab_and_return;
2348                }
2349                fprintf(o->file, "%s", header.buf);
2350                strbuf_reset(&header);
2351                if (DIFF_OPT_TST(o, BINARY))
2352                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2353                else
2354                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2355                                line_prefix, lbl[0], lbl[1]);
2356                o->found_changes = 1;
2357        } else {
2358                /* Crazy xdl interfaces.. */
2359                const char *diffopts = getenv("GIT_DIFF_OPTS");
2360                const char *v;
2361                xpparam_t xpp;
2362                xdemitconf_t xecfg;
2363                struct emit_callback ecbdata;
2364                const struct userdiff_funcname *pe;
2365
2366                if (must_show_header) {
2367                        fprintf(o->file, "%s", header.buf);
2368                        strbuf_reset(&header);
2369                }
2370
2371                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2372                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2373
2374                pe = diff_funcname_pattern(one);
2375                if (!pe)
2376                        pe = diff_funcname_pattern(two);
2377
2378                memset(&xpp, 0, sizeof(xpp));
2379                memset(&xecfg, 0, sizeof(xecfg));
2380                memset(&ecbdata, 0, sizeof(ecbdata));
2381                ecbdata.label_path = lbl;
2382                ecbdata.color_diff = want_color(o->use_color);
2383                ecbdata.found_changesp = &o->found_changes;
2384                ecbdata.ws_rule = whitespace_rule(name_b);
2385                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2386                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2387                ecbdata.opt = o;
2388                ecbdata.header = header.len ? &header : NULL;
2389                xpp.flags = o->xdl_opts;
2390                xecfg.ctxlen = o->context;
2391                xecfg.interhunkctxlen = o->interhunkcontext;
2392                xecfg.flags = XDL_EMIT_FUNCNAMES;
2393                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2394                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2395                if (pe)
2396                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2397                if (!diffopts)
2398                        ;
2399                else if (skip_prefix(diffopts, "--unified=", &v))
2400                        xecfg.ctxlen = strtoul(v, NULL, 10);
2401                else if (skip_prefix(diffopts, "-u", &v))
2402                        xecfg.ctxlen = strtoul(v, NULL, 10);
2403                if (o->word_diff)
2404                        init_diff_words_data(&ecbdata, o, one, two);
2405                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2406                              &xpp, &xecfg);
2407                if (o->word_diff)
2408                        free_diff_words_data(&ecbdata);
2409                if (textconv_one)
2410                        free(mf1.ptr);
2411                if (textconv_two)
2412                        free(mf2.ptr);
2413                xdiff_clear_find_func(&xecfg);
2414        }
2415
2416 free_ab_and_return:
2417        strbuf_release(&header);
2418        diff_free_filespec_data(one);
2419        diff_free_filespec_data(two);
2420        free(a_one);
2421        free(b_two);
2422        return;
2423}
2424
2425static void builtin_diffstat(const char *name_a, const char *name_b,
2426                             struct diff_filespec *one,
2427                             struct diff_filespec *two,
2428                             struct diffstat_t *diffstat,
2429                             struct diff_options *o,
2430                             struct diff_filepair *p)
2431{
2432        mmfile_t mf1, mf2;
2433        struct diffstat_file *data;
2434        int same_contents;
2435        int complete_rewrite = 0;
2436
2437        if (!DIFF_PAIR_UNMERGED(p)) {
2438                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2439                        complete_rewrite = 1;
2440        }
2441
2442        data = diffstat_add(diffstat, name_a, name_b);
2443        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2444
2445        if (!one || !two) {
2446                data->is_unmerged = 1;
2447                return;
2448        }
2449
2450        same_contents = !hashcmp(one->sha1, two->sha1);
2451
2452        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2453                data->is_binary = 1;
2454                if (same_contents) {
2455                        data->added = 0;
2456                        data->deleted = 0;
2457                } else {
2458                        data->added = diff_filespec_size(two);
2459                        data->deleted = diff_filespec_size(one);
2460                }
2461        }
2462
2463        else if (complete_rewrite) {
2464                diff_populate_filespec(one, 0);
2465                diff_populate_filespec(two, 0);
2466                data->deleted = count_lines(one->data, one->size);
2467                data->added = count_lines(two->data, two->size);
2468        }
2469
2470        else if (!same_contents) {
2471                /* Crazy xdl interfaces.. */
2472                xpparam_t xpp;
2473                xdemitconf_t xecfg;
2474
2475                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2476                        die("unable to read files to diff");
2477
2478                memset(&xpp, 0, sizeof(xpp));
2479                memset(&xecfg, 0, sizeof(xecfg));
2480                xpp.flags = o->xdl_opts;
2481                xecfg.ctxlen = o->context;
2482                xecfg.interhunkctxlen = o->interhunkcontext;
2483                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2484                              &xpp, &xecfg);
2485        }
2486
2487        diff_free_filespec_data(one);
2488        diff_free_filespec_data(two);
2489}
2490
2491static void builtin_checkdiff(const char *name_a, const char *name_b,
2492                              const char *attr_path,
2493                              struct diff_filespec *one,
2494                              struct diff_filespec *two,
2495                              struct diff_options *o)
2496{
2497        mmfile_t mf1, mf2;
2498        struct checkdiff_t data;
2499
2500        if (!two)
2501                return;
2502
2503        memset(&data, 0, sizeof(data));
2504        data.filename = name_b ? name_b : name_a;
2505        data.lineno = 0;
2506        data.o = o;
2507        data.ws_rule = whitespace_rule(attr_path);
2508        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2509
2510        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2511                die("unable to read files to diff");
2512
2513        /*
2514         * All the other codepaths check both sides, but not checking
2515         * the "old" side here is deliberate.  We are checking the newly
2516         * introduced changes, and as long as the "new" side is text, we
2517         * can and should check what it introduces.
2518         */
2519        if (diff_filespec_is_binary(two))
2520                goto free_and_return;
2521        else {
2522                /* Crazy xdl interfaces.. */
2523                xpparam_t xpp;
2524                xdemitconf_t xecfg;
2525
2526                memset(&xpp, 0, sizeof(xpp));
2527                memset(&xecfg, 0, sizeof(xecfg));
2528                xecfg.ctxlen = 1; /* at least one context line */
2529                xpp.flags = 0;
2530                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2531                              &xpp, &xecfg);
2532
2533                if (data.ws_rule & WS_BLANK_AT_EOF) {
2534                        struct emit_callback ecbdata;
2535                        int blank_at_eof;
2536
2537                        ecbdata.ws_rule = data.ws_rule;
2538                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2539                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2540
2541                        if (blank_at_eof) {
2542                                static char *err;
2543                                if (!err)
2544                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2545                                fprintf(o->file, "%s:%d: %s.\n",
2546                                        data.filename, blank_at_eof, err);
2547                                data.status = 1; /* report errors */
2548                        }
2549                }
2550        }
2551 free_and_return:
2552        diff_free_filespec_data(one);
2553        diff_free_filespec_data(two);
2554        if (data.status)
2555                DIFF_OPT_SET(o, CHECK_FAILED);
2556}
2557
2558struct diff_filespec *alloc_filespec(const char *path)
2559{
2560        int namelen = strlen(path);
2561        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2562
2563        memset(spec, 0, sizeof(*spec));
2564        spec->path = (char *)(spec + 1);
2565        memcpy(spec->path, path, namelen+1);
2566        spec->count = 1;
2567        spec->is_binary = -1;
2568        return spec;
2569}
2570
2571void free_filespec(struct diff_filespec *spec)
2572{
2573        if (!--spec->count) {
2574                diff_free_filespec_data(spec);
2575                free(spec);
2576        }
2577}
2578
2579void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2580                   int sha1_valid, unsigned short mode)
2581{
2582        if (mode) {
2583                spec->mode = canon_mode(mode);
2584                hashcpy(spec->sha1, sha1);
2585                spec->sha1_valid = sha1_valid;
2586        }
2587}
2588
2589/*
2590 * Given a name and sha1 pair, if the index tells us the file in
2591 * the work tree has that object contents, return true, so that
2592 * prepare_temp_file() does not have to inflate and extract.
2593 */
2594static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2595{
2596        const struct cache_entry *ce;
2597        struct stat st;
2598        int pos, len;
2599
2600        /*
2601         * We do not read the cache ourselves here, because the
2602         * benchmark with my previous version that always reads cache
2603         * shows that it makes things worse for diff-tree comparing
2604         * two linux-2.6 kernel trees in an already checked out work
2605         * tree.  This is because most diff-tree comparisons deal with
2606         * only a small number of files, while reading the cache is
2607         * expensive for a large project, and its cost outweighs the
2608         * savings we get by not inflating the object to a temporary
2609         * file.  Practically, this code only helps when we are used
2610         * by diff-cache --cached, which does read the cache before
2611         * calling us.
2612         */
2613        if (!active_cache)
2614                return 0;
2615
2616        /* We want to avoid the working directory if our caller
2617         * doesn't need the data in a normal file, this system
2618         * is rather slow with its stat/open/mmap/close syscalls,
2619         * and the object is contained in a pack file.  The pack
2620         * is probably already open and will be faster to obtain
2621         * the data through than the working directory.  Loose
2622         * objects however would tend to be slower as they need
2623         * to be individually opened and inflated.
2624         */
2625        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2626                return 0;
2627
2628        len = strlen(name);
2629        pos = cache_name_pos(name, len);
2630        if (pos < 0)
2631                return 0;
2632        ce = active_cache[pos];
2633
2634        /*
2635         * This is not the sha1 we are looking for, or
2636         * unreusable because it is not a regular file.
2637         */
2638        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2639                return 0;
2640
2641        /*
2642         * If ce is marked as "assume unchanged", there is no
2643         * guarantee that work tree matches what we are looking for.
2644         */
2645        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2646                return 0;
2647
2648        /*
2649         * If ce matches the file in the work tree, we can reuse it.
2650         */
2651        if (ce_uptodate(ce) ||
2652            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2653                return 1;
2654
2655        return 0;
2656}
2657
2658static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2659{
2660        int len;
2661        char *data = xmalloc(100), *dirty = "";
2662
2663        /* Are we looking at the work tree? */
2664        if (s->dirty_submodule)
2665                dirty = "-dirty";
2666
2667        len = snprintf(data, 100,
2668                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2669        s->data = data;
2670        s->size = len;
2671        s->should_free = 1;
2672        if (size_only) {
2673                s->data = NULL;
2674                free(data);
2675        }
2676        return 0;
2677}
2678
2679/*
2680 * While doing rename detection and pickaxe operation, we may need to
2681 * grab the data for the blob (or file) for our own in-core comparison.
2682 * diff_filespec has data and size fields for this purpose.
2683 */
2684int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2685{
2686        int size_only = flags & CHECK_SIZE_ONLY;
2687        int err = 0;
2688        /*
2689         * demote FAIL to WARN to allow inspecting the situation
2690         * instead of refusing.
2691         */
2692        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2693                                    ? SAFE_CRLF_WARN
2694                                    : safe_crlf);
2695
2696        if (!DIFF_FILE_VALID(s))
2697                die("internal error: asking to populate invalid file.");
2698        if (S_ISDIR(s->mode))
2699                return -1;
2700
2701        if (s->data)
2702                return 0;
2703
2704        if (size_only && 0 < s->size)
2705                return 0;
2706
2707        if (S_ISGITLINK(s->mode))
2708                return diff_populate_gitlink(s, size_only);
2709
2710        if (!s->sha1_valid ||
2711            reuse_worktree_file(s->path, s->sha1, 0)) {
2712                struct strbuf buf = STRBUF_INIT;
2713                struct stat st;
2714                int fd;
2715
2716                if (lstat(s->path, &st) < 0) {
2717                        if (errno == ENOENT) {
2718                        err_empty:
2719                                err = -1;
2720                        empty:
2721                                s->data = (char *)"";
2722                                s->size = 0;
2723                                return err;
2724                        }
2725                }
2726                s->size = xsize_t(st.st_size);
2727                if (!s->size)
2728                        goto empty;
2729                if (S_ISLNK(st.st_mode)) {
2730                        struct strbuf sb = STRBUF_INIT;
2731
2732                        if (strbuf_readlink(&sb, s->path, s->size))
2733                                goto err_empty;
2734                        s->size = sb.len;
2735                        s->data = strbuf_detach(&sb, NULL);
2736                        s->should_free = 1;
2737                        return 0;
2738                }
2739                if (size_only)
2740                        return 0;
2741                if ((flags & CHECK_BINARY) &&
2742                    s->size > big_file_threshold && s->is_binary == -1) {
2743                        s->is_binary = 1;
2744                        return 0;
2745                }
2746                fd = open(s->path, O_RDONLY);
2747                if (fd < 0)
2748                        goto err_empty;
2749                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2750                close(fd);
2751                s->should_munmap = 1;
2752
2753                /*
2754                 * Convert from working tree format to canonical git format
2755                 */
2756                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2757                        size_t size = 0;
2758                        munmap(s->data, s->size);
2759                        s->should_munmap = 0;
2760                        s->data = strbuf_detach(&buf, &size);
2761                        s->size = size;
2762                        s->should_free = 1;
2763                }
2764        }
2765        else {
2766                enum object_type type;
2767                if (size_only || (flags & CHECK_BINARY)) {
2768                        type = sha1_object_info(s->sha1, &s->size);
2769                        if (type < 0)
2770                                die("unable to read %s", sha1_to_hex(s->sha1));
2771                        if (size_only)
2772                                return 0;
2773                        if (s->size > big_file_threshold && s->is_binary == -1) {
2774                                s->is_binary = 1;
2775                                return 0;
2776                        }
2777                }
2778                s->data = read_sha1_file(s->sha1, &type, &s->size);
2779                if (!s->data)
2780                        die("unable to read %s", sha1_to_hex(s->sha1));
2781                s->should_free = 1;
2782        }
2783        return 0;
2784}
2785
2786void diff_free_filespec_blob(struct diff_filespec *s)
2787{
2788        if (s->should_free)
2789                free(s->data);
2790        else if (s->should_munmap)
2791                munmap(s->data, s->size);
2792
2793        if (s->should_free || s->should_munmap) {
2794                s->should_free = s->should_munmap = 0;
2795                s->data = NULL;
2796        }
2797}
2798
2799void diff_free_filespec_data(struct diff_filespec *s)
2800{
2801        diff_free_filespec_blob(s);
2802        free(s->cnt_data);
2803        s->cnt_data = NULL;
2804}
2805
2806static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2807                           void *blob,
2808                           unsigned long size,
2809                           const unsigned char *sha1,
2810                           int mode)
2811{
2812        int fd;
2813        struct strbuf buf = STRBUF_INIT;
2814        struct strbuf template = STRBUF_INIT;
2815        char *path_dup = xstrdup(path);
2816        const char *base = basename(path_dup);
2817
2818        /* Generate "XXXXXX_basename.ext" */
2819        strbuf_addstr(&template, "XXXXXX_");
2820        strbuf_addstr(&template, base);
2821
2822        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2823                        strlen(base) + 1);
2824        if (fd < 0)
2825                die_errno("unable to create temp-file");
2826        if (convert_to_working_tree(path,
2827                        (const char *)blob, (size_t)size, &buf)) {
2828                blob = buf.buf;
2829                size = buf.len;
2830        }
2831        if (write_in_full(fd, blob, size) != size)
2832                die_errno("unable to write temp-file");
2833        close(fd);
2834        temp->name = temp->tmp_path;
2835        strcpy(temp->hex, sha1_to_hex(sha1));
2836        temp->hex[40] = 0;
2837        sprintf(temp->mode, "%06o", mode);
2838        strbuf_release(&buf);
2839        strbuf_release(&template);
2840        free(path_dup);
2841}
2842
2843static struct diff_tempfile *prepare_temp_file(const char *name,
2844                struct diff_filespec *one)
2845{
2846        struct diff_tempfile *temp = claim_diff_tempfile();
2847
2848        if (!DIFF_FILE_VALID(one)) {
2849        not_a_valid_file:
2850                /* A '-' entry produces this for file-2, and
2851                 * a '+' entry produces this for file-1.
2852                 */
2853                temp->name = "/dev/null";
2854                strcpy(temp->hex, ".");
2855                strcpy(temp->mode, ".");
2856                return temp;
2857        }
2858
2859        if (!remove_tempfile_installed) {
2860                atexit(remove_tempfile);
2861                sigchain_push_common(remove_tempfile_on_signal);
2862                remove_tempfile_installed = 1;
2863        }
2864
2865        if (!S_ISGITLINK(one->mode) &&
2866            (!one->sha1_valid ||
2867             reuse_worktree_file(name, one->sha1, 1))) {
2868                struct stat st;
2869                if (lstat(name, &st) < 0) {
2870                        if (errno == ENOENT)
2871                                goto not_a_valid_file;
2872                        die_errno("stat(%s)", name);
2873                }
2874                if (S_ISLNK(st.st_mode)) {
2875                        struct strbuf sb = STRBUF_INIT;
2876                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2877                                die_errno("readlink(%s)", name);
2878                        prep_temp_blob(name, temp, sb.buf, sb.len,
2879                                       (one->sha1_valid ?
2880                                        one->sha1 : null_sha1),
2881                                       (one->sha1_valid ?
2882                                        one->mode : S_IFLNK));
2883                        strbuf_release(&sb);
2884                }
2885                else {
2886                        /* we can borrow from the file in the work tree */
2887                        temp->name = name;
2888                        if (!one->sha1_valid)
2889                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2890                        else
2891                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2892                        /* Even though we may sometimes borrow the
2893                         * contents from the work tree, we always want
2894                         * one->mode.  mode is trustworthy even when
2895                         * !(one->sha1_valid), as long as
2896                         * DIFF_FILE_VALID(one).
2897                         */
2898                        sprintf(temp->mode, "%06o", one->mode);
2899                }
2900                return temp;
2901        }
2902        else {
2903                if (diff_populate_filespec(one, 0))
2904                        die("cannot read data blob for %s", one->path);
2905                prep_temp_blob(name, temp, one->data, one->size,
2906                               one->sha1, one->mode);
2907        }
2908        return temp;
2909}
2910
2911static void add_external_diff_name(struct argv_array *argv,
2912                                   const char *name,
2913                                   struct diff_filespec *df)
2914{
2915        struct diff_tempfile *temp = prepare_temp_file(name, df);
2916        argv_array_push(argv, temp->name);
2917        argv_array_push(argv, temp->hex);
2918        argv_array_push(argv, temp->mode);
2919}
2920
2921/* An external diff command takes:
2922 *
2923 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2924 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2925 *
2926 */
2927static void run_external_diff(const char *pgm,
2928                              const char *name,
2929                              const char *other,
2930                              struct diff_filespec *one,
2931                              struct diff_filespec *two,
2932                              const char *xfrm_msg,
2933                              int complete_rewrite,
2934                              struct diff_options *o)
2935{
2936        struct argv_array argv = ARGV_ARRAY_INIT;
2937        struct argv_array env = ARGV_ARRAY_INIT;
2938        struct diff_queue_struct *q = &diff_queued_diff;
2939
2940        argv_array_push(&argv, pgm);
2941        argv_array_push(&argv, name);
2942
2943        if (one && two) {
2944                add_external_diff_name(&argv, name, one);
2945                if (!other)
2946                        add_external_diff_name(&argv, name, two);
2947                else {
2948                        add_external_diff_name(&argv, other, two);
2949                        argv_array_push(&argv, other);
2950                        argv_array_push(&argv, xfrm_msg);
2951                }
2952        }
2953
2954        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2955        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2956
2957        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2958                die(_("external diff died, stopping at %s"), name);
2959
2960        remove_tempfile();
2961        argv_array_clear(&argv);
2962        argv_array_clear(&env);
2963}
2964
2965static int similarity_index(struct diff_filepair *p)
2966{
2967        return p->score * 100 / MAX_SCORE;
2968}
2969
2970static void fill_metainfo(struct strbuf *msg,
2971                          const char *name,
2972                          const char *other,
2973                          struct diff_filespec *one,
2974                          struct diff_filespec *two,
2975                          struct diff_options *o,
2976                          struct diff_filepair *p,
2977                          int *must_show_header,
2978                          int use_color)
2979{
2980        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2981        const char *reset = diff_get_color(use_color, DIFF_RESET);
2982        const char *line_prefix = diff_line_prefix(o);
2983
2984        *must_show_header = 1;
2985        strbuf_init(msg, PATH_MAX * 2 + 300);
2986        switch (p->status) {
2987        case DIFF_STATUS_COPIED:
2988                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2989                            line_prefix, set, similarity_index(p));
2990                strbuf_addf(msg, "%s\n%s%scopy from ",
2991                            reset,  line_prefix, set);
2992                quote_c_style(name, msg, NULL, 0);
2993                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2994                quote_c_style(other, msg, NULL, 0);
2995                strbuf_addf(msg, "%s\n", reset);
2996                break;
2997        case DIFF_STATUS_RENAMED:
2998                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2999                            line_prefix, set, similarity_index(p));
3000                strbuf_addf(msg, "%s\n%s%srename from ",
3001                            reset, line_prefix, set);
3002                quote_c_style(name, msg, NULL, 0);
3003                strbuf_addf(msg, "%s\n%s%srename to ",
3004                            reset, line_prefix, set);
3005                quote_c_style(other, msg, NULL, 0);
3006                strbuf_addf(msg, "%s\n", reset);
3007                break;
3008        case DIFF_STATUS_MODIFIED:
3009                if (p->score) {
3010                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3011                                    line_prefix,
3012                                    set, similarity_index(p), reset);
3013                        break;
3014                }
3015                /* fallthru */
3016        default:
3017                *must_show_header = 0;
3018        }
3019        if (one && two && hashcmp(one->sha1, two->sha1)) {
3020                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3021
3022                if (DIFF_OPT_TST(o, BINARY)) {
3023                        mmfile_t mf;
3024                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3025                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3026                                abbrev = 40;
3027                }
3028                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3029                            find_unique_abbrev(one->sha1, abbrev));
3030                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3031                if (one->mode == two->mode)
3032                        strbuf_addf(msg, " %06o", one->mode);
3033                strbuf_addf(msg, "%s\n", reset);
3034        }
3035}
3036
3037static void run_diff_cmd(const char *pgm,
3038                         const char *name,
3039                         const char *other,
3040                         const char *attr_path,
3041                         struct diff_filespec *one,
3042                         struct diff_filespec *two,
3043                         struct strbuf *msg,
3044                         struct diff_options *o,
3045                         struct diff_filepair *p)
3046{
3047        const char *xfrm_msg = NULL;
3048        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3049        int must_show_header = 0;
3050
3051
3052        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3053                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3054                if (drv && drv->external)
3055                        pgm = drv->external;
3056        }
3057
3058        if (msg) {
3059                /*
3060                 * don't use colors when the header is intended for an
3061                 * external diff driver
3062                 */
3063                fill_metainfo(msg, name, other, one, two, o, p,
3064                              &must_show_header,
3065                              want_color(o->use_color) && !pgm);
3066                xfrm_msg = msg->len ? msg->buf : NULL;
3067        }
3068
3069        if (pgm) {
3070                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3071                                  complete_rewrite, o);
3072                return;
3073        }
3074        if (one && two)
3075                builtin_diff(name, other ? other : name,
3076                             one, two, xfrm_msg, must_show_header,
3077                             o, complete_rewrite);
3078        else
3079                fprintf(o->file, "* Unmerged path %s\n", name);
3080}
3081
3082static void diff_fill_sha1_info(struct diff_filespec *one)
3083{
3084        if (DIFF_FILE_VALID(one)) {
3085                if (!one->sha1_valid) {
3086                        struct stat st;
3087                        if (one->is_stdin) {
3088                                hashcpy(one->sha1, null_sha1);
3089                                return;
3090                        }
3091                        if (lstat(one->path, &st) < 0)
3092                                die_errno("stat '%s'", one->path);
3093                        if (index_path(one->sha1, one->path, &st, 0))
3094                                die("cannot hash %s", one->path);
3095                }
3096        }
3097        else
3098                hashclr(one->sha1);
3099}
3100
3101static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3102{
3103        /* Strip the prefix but do not molest /dev/null and absolute paths */
3104        if (*namep && **namep != '/') {
3105                *namep += prefix_length;
3106                if (**namep == '/')
3107                        ++*namep;
3108        }
3109        if (*otherp && **otherp != '/') {
3110                *otherp += prefix_length;
3111                if (**otherp == '/')
3112                        ++*otherp;
3113        }
3114}
3115
3116static void run_diff(struct diff_filepair *p, struct diff_options *o)
3117{
3118        const char *pgm = external_diff();
3119        struct strbuf msg;
3120        struct diff_filespec *one = p->one;
3121        struct diff_filespec *two = p->two;
3122        const char *name;
3123        const char *other;
3124        const char *attr_path;
3125
3126        name  = p->one->path;
3127        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3128        attr_path = name;
3129        if (o->prefix_length)
3130                strip_prefix(o->prefix_length, &name, &other);
3131
3132        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3133                pgm = NULL;
3134
3135        if (DIFF_PAIR_UNMERGED(p)) {
3136                run_diff_cmd(pgm, name, NULL, attr_path,
3137                             NULL, NULL, NULL, o, p);
3138                return;
3139        }
3140
3141        diff_fill_sha1_info(one);
3142        diff_fill_sha1_info(two);
3143
3144        if (!pgm &&
3145            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3146            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3147                /*
3148                 * a filepair that changes between file and symlink
3149                 * needs to be split into deletion and creation.
3150                 */
3151                struct diff_filespec *null = alloc_filespec(two->path);
3152                run_diff_cmd(NULL, name, other, attr_path,
3153                             one, null, &msg, o, p);
3154                free(null);
3155                strbuf_release(&msg);
3156
3157                null = alloc_filespec(one->path);
3158                run_diff_cmd(NULL, name, other, attr_path,
3159                             null, two, &msg, o, p);
3160                free(null);
3161        }
3162        else
3163                run_diff_cmd(pgm, name, other, attr_path,
3164                             one, two, &msg, o, p);
3165
3166        strbuf_release(&msg);
3167}
3168
3169static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3170                         struct diffstat_t *diffstat)
3171{
3172        const char *name;
3173        const char *other;
3174
3175        if (DIFF_PAIR_UNMERGED(p)) {
3176                /* unmerged */
3177                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3178                return;
3179        }
3180
3181        name = p->one->path;
3182        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3183
3184        if (o->prefix_length)
3185                strip_prefix(o->prefix_length, &name, &other);
3186
3187        diff_fill_sha1_info(p->one);
3188        diff_fill_sha1_info(p->two);
3189
3190        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3191}
3192
3193static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3194{
3195        const char *name;
3196        const char *other;
3197        const char *attr_path;
3198
3199        if (DIFF_PAIR_UNMERGED(p)) {
3200                /* unmerged */
3201                return;
3202        }
3203
3204        name = p->one->path;
3205        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3206        attr_path = other ? other : name;
3207
3208        if (o->prefix_length)
3209                strip_prefix(o->prefix_length, &name, &other);
3210
3211        diff_fill_sha1_info(p->one);
3212        diff_fill_sha1_info(p->two);
3213
3214        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3215}
3216
3217void diff_setup(struct diff_options *options)
3218{
3219        memcpy(options, &default_diff_options, sizeof(*options));
3220
3221        options->file = stdout;
3222
3223        options->line_termination = '\n';
3224        options->break_opt = -1;
3225        options->rename_limit = -1;
3226        options->dirstat_permille = diff_dirstat_permille_default;
3227        options->context = diff_context_default;
3228        DIFF_OPT_SET(options, RENAME_EMPTY);
3229
3230        /* pathchange left =NULL by default */
3231        options->change = diff_change;
3232        options->add_remove = diff_addremove;
3233        options->use_color = diff_use_color_default;
3234        options->detect_rename = diff_detect_rename_default;
3235        options->xdl_opts |= diff_algorithm;
3236
3237        options->orderfile = diff_order_file_cfg;
3238
3239        if (diff_no_prefix) {
3240                options->a_prefix = options->b_prefix = "";
3241        } else if (!diff_mnemonic_prefix) {
3242                options->a_prefix = "a/";
3243                options->b_prefix = "b/";
3244        }
3245}
3246
3247void diff_setup_done(struct diff_options *options)
3248{
3249        int count = 0;
3250
3251        if (options->set_default)
3252                options->set_default(options);
3253
3254        if (options->output_format & DIFF_FORMAT_NAME)
3255                count++;
3256        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3257                count++;
3258        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3259                count++;
3260        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3261                count++;
3262        if (count > 1)
3263                die("--name-only, --name-status, --check and -s are mutually exclusive");
3264
3265        /*
3266         * Most of the time we can say "there are changes"
3267         * only by checking if there are changed paths, but
3268         * --ignore-whitespace* options force us to look
3269         * inside contents.
3270         */
3271
3272        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3273            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3274            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3275                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3276        else
3277                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3278
3279        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3280                options->detect_rename = DIFF_DETECT_COPY;
3281
3282        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3283                options->prefix = NULL;
3284        if (options->prefix)
3285                options->prefix_length = strlen(options->prefix);
3286        else
3287                options->prefix_length = 0;
3288
3289        if (options->output_format & (DIFF_FORMAT_NAME |
3290                                      DIFF_FORMAT_NAME_STATUS |
3291                                      DIFF_FORMAT_CHECKDIFF |
3292                                      DIFF_FORMAT_NO_OUTPUT))
3293                options->output_format &= ~(DIFF_FORMAT_RAW |
3294                                            DIFF_FORMAT_NUMSTAT |
3295                                            DIFF_FORMAT_DIFFSTAT |
3296                                            DIFF_FORMAT_SHORTSTAT |
3297                                            DIFF_FORMAT_DIRSTAT |
3298                                            DIFF_FORMAT_SUMMARY |
3299                                            DIFF_FORMAT_PATCH);
3300
3301        /*
3302         * These cases always need recursive; we do not drop caller-supplied
3303         * recursive bits for other formats here.
3304         */
3305        if (options->output_format & (DIFF_FORMAT_PATCH |
3306                                      DIFF_FORMAT_NUMSTAT |
3307                                      DIFF_FORMAT_DIFFSTAT |
3308                                      DIFF_FORMAT_SHORTSTAT |
3309                                      DIFF_FORMAT_DIRSTAT |
3310                                      DIFF_FORMAT_SUMMARY |
3311                                      DIFF_FORMAT_CHECKDIFF))
3312                DIFF_OPT_SET(options, RECURSIVE);
3313        /*
3314         * Also pickaxe would not work very well if you do not say recursive
3315         */
3316        if (options->pickaxe)
3317                DIFF_OPT_SET(options, RECURSIVE);
3318        /*
3319         * When patches are generated, submodules diffed against the work tree
3320         * must be checked for dirtiness too so it can be shown in the output
3321         */
3322        if (options->output_format & DIFF_FORMAT_PATCH)
3323                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3324
3325        if (options->detect_rename && options->rename_limit < 0)
3326                options->rename_limit = diff_rename_limit_default;
3327        if (options->setup & DIFF_SETUP_USE_CACHE) {
3328                if (!active_cache)
3329                        /* read-cache does not die even when it fails
3330                         * so it is safe for us to do this here.  Also
3331                         * it does not smudge active_cache or active_nr
3332                         * when it fails, so we do not have to worry about
3333                         * cleaning it up ourselves either.
3334                         */
3335                        read_cache();
3336        }
3337        if (options->abbrev <= 0 || 40 < options->abbrev)
3338                options->abbrev = 40; /* full */
3339
3340        /*
3341         * It does not make sense to show the first hit we happened
3342         * to have found.  It does not make sense not to return with
3343         * exit code in such a case either.
3344         */
3345        if (DIFF_OPT_TST(options, QUICK)) {
3346                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3347                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3348        }
3349
3350        options->diff_path_counter = 0;
3351
3352        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3353                die(_("--follow requires exactly one pathspec"));
3354}
3355
3356static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3357{
3358        char c, *eq;
3359        int len;
3360
3361        if (*arg != '-')
3362                return 0;
3363        c = *++arg;
3364        if (!c)
3365                return 0;
3366        if (c == arg_short) {
3367                c = *++arg;
3368                if (!c)
3369                        return 1;
3370                if (val && isdigit(c)) {
3371                        char *end;
3372                        int n = strtoul(arg, &end, 10);
3373                        if (*end)
3374                                return 0;
3375                        *val = n;
3376                        return 1;
3377                }
3378                return 0;
3379        }
3380        if (c != '-')
3381                return 0;
3382        arg++;
3383        eq = strchrnul(arg, '=');
3384        len = eq - arg;
3385        if (!len || strncmp(arg, arg_long, len))
3386                return 0;
3387        if (*eq) {
3388                int n;
3389                char *end;
3390                if (!isdigit(*++eq))
3391                        return 0;
3392                n = strtoul(eq, &end, 10);
3393                if (*end)
3394                        return 0;
3395                *val = n;
3396        }
3397        return 1;
3398}
3399
3400static int diff_scoreopt_parse(const char *opt);
3401
3402static inline int short_opt(char opt, const char **argv,
3403                            const char **optarg)
3404{
3405        const char *arg = argv[0];
3406        if (arg[0] != '-' || arg[1] != opt)
3407                return 0;
3408        if (arg[2] != '\0') {
3409                *optarg = arg + 2;
3410                return 1;
3411        }
3412        if (!argv[1])
3413                die("Option '%c' requires a value", opt);
3414        *optarg = argv[1];
3415        return 2;
3416}
3417
3418int parse_long_opt(const char *opt, const char **argv,
3419                   const char **optarg)
3420{
3421        const char *arg = argv[0];
3422        if (!skip_prefix(arg, "--", &arg))
3423                return 0;
3424        if (!skip_prefix(arg, opt, &arg))
3425                return 0;
3426        if (*arg == '=') { /* stuck form: --option=value */
3427                *optarg = arg + 1;
3428                return 1;
3429        }
3430        if (*arg != '\0')
3431                return 0;
3432        /* separate form: --option value */
3433        if (!argv[1])
3434                die("Option '--%s' requires a value", opt);
3435        *optarg = argv[1];
3436        return 2;
3437}
3438
3439static int stat_opt(struct diff_options *options, const char **av)
3440{
3441        const char *arg = av[0];
3442        char *end;
3443        int width = options->stat_width;
3444        int name_width = options->stat_name_width;
3445        int graph_width = options->stat_graph_width;
3446        int count = options->stat_count;
3447        int argcount = 1;
3448
3449        if (!skip_prefix(arg, "--stat", &arg))
3450                die("BUG: stat option does not begin with --stat: %s", arg);
3451        end = (char *)arg;
3452
3453        switch (*arg) {
3454        case '-':
3455                if (skip_prefix(arg, "-width", &arg)) {
3456                        if (*arg == '=')
3457                                width = strtoul(arg + 1, &end, 10);
3458                        else if (!*arg && !av[1])
3459                                die("Option '--stat-width' requires a value");
3460                        else if (!*arg) {
3461                                width = strtoul(av[1], &end, 10);
3462                                argcount = 2;
3463                        }
3464                } else if (skip_prefix(arg, "-name-width", &arg)) {
3465                        if (*arg == '=')
3466                                name_width = strtoul(arg + 1, &end, 10);
3467                        else if (!*arg && !av[1])
3468                                die("Option '--stat-name-width' requires a value");
3469                        else if (!*arg) {
3470                                name_width = strtoul(av[1], &end, 10);
3471                                argcount = 2;
3472                        }
3473                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3474                        if (*arg == '=')
3475                                graph_width = strtoul(arg + 1, &end, 10);
3476                        else if (!*arg && !av[1])
3477                                die("Option '--stat-graph-width' requires a value");
3478                        else if (!*arg) {
3479                                graph_width = strtoul(av[1], &end, 10);
3480                                argcount = 2;
3481                        }
3482                } else if (skip_prefix(arg, "-count", &arg)) {
3483                        if (*arg == '=')
3484                                count = strtoul(arg + 1, &end, 10);
3485                        else if (!*arg && !av[1])
3486                                die("Option '--stat-count' requires a value");
3487                        else if (!*arg) {
3488                                count = strtoul(av[1], &end, 10);
3489                                argcount = 2;
3490                        }
3491                }
3492                break;
3493        case '=':
3494                width = strtoul(arg+1, &end, 10);
3495                if (*end == ',')
3496                        name_width = strtoul(end+1, &end, 10);
3497                if (*end == ',')
3498                        count = strtoul(end+1, &end, 10);
3499        }
3500
3501        /* Important! This checks all the error cases! */
3502        if (*end)
3503                return 0;
3504        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3505        options->stat_name_width = name_width;
3506        options->stat_graph_width = graph_width;
3507        options->stat_width = width;
3508        options->stat_count = count;
3509        return argcount;
3510}
3511
3512static int parse_dirstat_opt(struct diff_options *options, const char *params)
3513{
3514        struct strbuf errmsg = STRBUF_INIT;
3515        if (parse_dirstat_params(options, params, &errmsg))
3516                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3517                    errmsg.buf);
3518        strbuf_release(&errmsg);
3519        /*
3520         * The caller knows a dirstat-related option is given from the command
3521         * line; allow it to say "return this_function();"
3522         */
3523        options->output_format |= DIFF_FORMAT_DIRSTAT;
3524        return 1;
3525}
3526
3527static int parse_submodule_opt(struct diff_options *options, const char *value)
3528{
3529        if (parse_submodule_params(options, value))
3530                die(_("Failed to parse --submodule option parameter: '%s'"),
3531                        value);
3532        return 1;
3533}
3534
3535static const char diff_status_letters[] = {
3536        DIFF_STATUS_ADDED,
3537        DIFF_STATUS_COPIED,
3538        DIFF_STATUS_DELETED,
3539        DIFF_STATUS_MODIFIED,
3540        DIFF_STATUS_RENAMED,
3541        DIFF_STATUS_TYPE_CHANGED,
3542        DIFF_STATUS_UNKNOWN,
3543        DIFF_STATUS_UNMERGED,
3544        DIFF_STATUS_FILTER_AON,
3545        DIFF_STATUS_FILTER_BROKEN,
3546        '\0',
3547};
3548
3549static unsigned int filter_bit['Z' + 1];
3550
3551static void prepare_filter_bits(void)
3552{
3553        int i;
3554
3555        if (!filter_bit[DIFF_STATUS_ADDED]) {
3556                for (i = 0; diff_status_letters[i]; i++)
3557                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3558        }
3559}
3560
3561static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3562{
3563        return opt->filter & filter_bit[(int) status];
3564}
3565
3566static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3567{
3568        int i, optch;
3569
3570        prepare_filter_bits();
3571
3572        /*
3573         * If there is a negation e.g. 'd' in the input, and we haven't
3574         * initialized the filter field with another --diff-filter, start
3575         * from full set of bits, except for AON.
3576         */
3577        if (!opt->filter) {
3578                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3579                        if (optch < 'a' || 'z' < optch)
3580                                continue;
3581                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3582                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3583                        break;
3584                }
3585        }
3586
3587        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3588                unsigned int bit;
3589                int negate;
3590
3591                if ('a' <= optch && optch <= 'z') {
3592                        negate = 1;
3593                        optch = toupper(optch);
3594                } else {
3595                        negate = 0;
3596                }
3597
3598                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3599                if (!bit)
3600                        return optarg[i];
3601                if (negate)
3602                        opt->filter &= ~bit;
3603                else
3604                        opt->filter |= bit;
3605        }
3606        return 0;
3607}
3608
3609static void enable_patch_output(int *fmt) {
3610        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3611        *fmt |= DIFF_FORMAT_PATCH;
3612}
3613
3614int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3615{
3616        const char *arg = av[0];
3617        const char *optarg;
3618        int argcount;
3619
3620        /* Output format options */
3621        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3622            || opt_arg(arg, 'U', "unified", &options->context))
3623                enable_patch_output(&options->output_format);
3624        else if (!strcmp(arg, "--raw"))
3625                options->output_format |= DIFF_FORMAT_RAW;
3626        else if (!strcmp(arg, "--patch-with-raw")) {
3627                enable_patch_output(&options->output_format);
3628                options->output_format |= DIFF_FORMAT_RAW;
3629        } else if (!strcmp(arg, "--numstat"))
3630                options->output_format |= DIFF_FORMAT_NUMSTAT;
3631        else if (!strcmp(arg, "--shortstat"))
3632                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3633        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3634                return parse_dirstat_opt(options, "");
3635        else if (skip_prefix(arg, "-X", &arg))
3636                return parse_dirstat_opt(options, arg);
3637        else if (skip_prefix(arg, "--dirstat=", &arg))
3638                return parse_dirstat_opt(options, arg);
3639        else if (!strcmp(arg, "--cumulative"))
3640                return parse_dirstat_opt(options, "cumulative");
3641        else if (!strcmp(arg, "--dirstat-by-file"))
3642                return parse_dirstat_opt(options, "files");
3643        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3644                parse_dirstat_opt(options, "files");
3645                return parse_dirstat_opt(options, arg);
3646        }
3647        else if (!strcmp(arg, "--check"))
3648                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3649        else if (!strcmp(arg, "--summary"))
3650                options->output_format |= DIFF_FORMAT_SUMMARY;
3651        else if (!strcmp(arg, "--patch-with-stat")) {
3652                enable_patch_output(&options->output_format);
3653                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3654        } else if (!strcmp(arg, "--name-only"))
3655                options->output_format |= DIFF_FORMAT_NAME;
3656        else if (!strcmp(arg, "--name-status"))
3657                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3658        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3659                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3660        else if (starts_with(arg, "--stat"))
3661                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3662                return stat_opt(options, av);
3663
3664        /* renames options */
3665        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3666                 !strcmp(arg, "--break-rewrites")) {
3667                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3668                        return error("invalid argument to -B: %s", arg+2);
3669        }
3670        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3671                 !strcmp(arg, "--find-renames")) {
3672                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3673                        return error("invalid argument to -M: %s", arg+2);
3674                options->detect_rename = DIFF_DETECT_RENAME;
3675        }
3676        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3677                options->irreversible_delete = 1;
3678        }
3679        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3680                 !strcmp(arg, "--find-copies")) {
3681                if (options->detect_rename == DIFF_DETECT_COPY)
3682                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3683                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3684                        return error("invalid argument to -C: %s", arg+2);
3685                options->detect_rename = DIFF_DETECT_COPY;
3686        }
3687        else if (!strcmp(arg, "--no-renames"))
3688                options->detect_rename = 0;
3689        else if (!strcmp(arg, "--rename-empty"))
3690                DIFF_OPT_SET(options, RENAME_EMPTY);
3691        else if (!strcmp(arg, "--no-rename-empty"))
3692                DIFF_OPT_CLR(options, RENAME_EMPTY);
3693        else if (!strcmp(arg, "--relative"))
3694                DIFF_OPT_SET(options, RELATIVE_NAME);
3695        else if (skip_prefix(arg, "--relative=", &arg)) {
3696                DIFF_OPT_SET(options, RELATIVE_NAME);
3697                options->prefix = arg;
3698        }
3699
3700        /* xdiff options */
3701        else if (!strcmp(arg, "--minimal"))
3702                DIFF_XDL_SET(options, NEED_MINIMAL);
3703        else if (!strcmp(arg, "--no-minimal"))
3704                DIFF_XDL_CLR(options, NEED_MINIMAL);
3705        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3706                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3707        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3708                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3709        else if (!strcmp(arg, "--ignore-space-at-eol"))
3710                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3711        else if (!strcmp(arg, "--ignore-blank-lines"))
3712                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3713        else if (!strcmp(arg, "--patience"))
3714                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3715        else if (!strcmp(arg, "--histogram"))
3716                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3717        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3718                long value = parse_algorithm_value(optarg);
3719                if (value < 0)
3720                        return error("option diff-algorithm accepts \"myers\", "
3721                                     "\"minimal\", \"patience\" and \"histogram\"");
3722                /* clear out previous settings */
3723                DIFF_XDL_CLR(options, NEED_MINIMAL);
3724                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3725                options->xdl_opts |= value;
3726                return argcount;
3727        }
3728
3729        /* flags options */
3730        else if (!strcmp(arg, "--binary")) {
3731                enable_patch_output(&options->output_format);
3732                DIFF_OPT_SET(options, BINARY);
3733        }
3734        else if (!strcmp(arg, "--full-index"))
3735                DIFF_OPT_SET(options, FULL_INDEX);
3736        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3737                DIFF_OPT_SET(options, TEXT);
3738        else if (!strcmp(arg, "-R"))
3739                DIFF_OPT_SET(options, REVERSE_DIFF);
3740        else if (!strcmp(arg, "--find-copies-harder"))
3741                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3742        else if (!strcmp(arg, "--follow"))
3743                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3744        else if (!strcmp(arg, "--no-follow"))
3745                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3746        else if (!strcmp(arg, "--color"))
3747                options->use_color = 1;
3748        else if (skip_prefix(arg, "--color=", &arg)) {
3749                int value = git_config_colorbool(NULL, arg);
3750                if (value < 0)
3751                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3752                options->use_color = value;
3753        }
3754        else if (!strcmp(arg, "--no-color"))
3755                options->use_color = 0;
3756        else if (!strcmp(arg, "--color-words")) {
3757                options->use_color = 1;
3758                options->word_diff = DIFF_WORDS_COLOR;
3759        }
3760        else if (skip_prefix(arg, "--color-words=", &arg)) {
3761                options->use_color = 1;
3762                options->word_diff = DIFF_WORDS_COLOR;
3763                options->word_regex = arg;
3764        }
3765        else if (!strcmp(arg, "--word-diff")) {
3766                if (options->word_diff == DIFF_WORDS_NONE)
3767                        options->word_diff = DIFF_WORDS_PLAIN;
3768        }
3769        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3770                if (!strcmp(arg, "plain"))
3771                        options->word_diff = DIFF_WORDS_PLAIN;
3772                else if (!strcmp(arg, "color")) {
3773                        options->use_color = 1;
3774                        options->word_diff = DIFF_WORDS_COLOR;
3775                }
3776                else if (!strcmp(arg, "porcelain"))
3777                        options->word_diff = DIFF_WORDS_PORCELAIN;
3778                else if (!strcmp(arg, "none"))
3779                        options->word_diff = DIFF_WORDS_NONE;
3780                else
3781                        die("bad --word-diff argument: %s", arg);
3782        }
3783        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3784                if (options->word_diff == DIFF_WORDS_NONE)
3785                        options->word_diff = DIFF_WORDS_PLAIN;
3786                options->word_regex = optarg;
3787                return argcount;
3788        }
3789        else if (!strcmp(arg, "--exit-code"))
3790                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3791        else if (!strcmp(arg, "--quiet"))
3792                DIFF_OPT_SET(options, QUICK);
3793        else if (!strcmp(arg, "--ext-diff"))
3794                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3795        else if (!strcmp(arg, "--no-ext-diff"))
3796                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3797        else if (!strcmp(arg, "--textconv"))
3798                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3799        else if (!strcmp(arg, "--no-textconv"))
3800                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3801        else if (!strcmp(arg, "--ignore-submodules")) {
3802                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3803                handle_ignore_submodules_arg(options, "all");
3804        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3805                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3806                handle_ignore_submodules_arg(options, arg);
3807        } else if (!strcmp(arg, "--submodule"))
3808                DIFF_OPT_SET(options, SUBMODULE_LOG);
3809        else if (skip_prefix(arg, "--submodule=", &arg))
3810                return parse_submodule_opt(options, arg);
3811
3812        /* misc options */
3813        else if (!strcmp(arg, "-z"))
3814                options->line_termination = 0;
3815        else if ((argcount = short_opt('l', av, &optarg))) {
3816                options->rename_limit = strtoul(optarg, NULL, 10);
3817                return argcount;
3818        }
3819        else if ((argcount = short_opt('S', av, &optarg))) {
3820                options->pickaxe = optarg;
3821                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3822                return argcount;
3823        } else if ((argcount = short_opt('G', av, &optarg))) {
3824                options->pickaxe = optarg;
3825                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3826                return argcount;
3827        }
3828        else if (!strcmp(arg, "--pickaxe-all"))
3829                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3830        else if (!strcmp(arg, "--pickaxe-regex"))
3831                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3832        else if ((argcount = short_opt('O', av, &optarg))) {
3833                options->orderfile = optarg;
3834                return argcount;
3835        }
3836        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3837                int offending = parse_diff_filter_opt(optarg, options);
3838                if (offending)
3839                        die("unknown change class '%c' in --diff-filter=%s",
3840                            offending, optarg);
3841                return argcount;
3842        }
3843        else if (!strcmp(arg, "--abbrev"))
3844                options->abbrev = DEFAULT_ABBREV;
3845        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3846                options->abbrev = strtoul(arg, NULL, 10);
3847                if (options->abbrev < MINIMUM_ABBREV)
3848                        options->abbrev = MINIMUM_ABBREV;
3849                else if (40 < options->abbrev)
3850                        options->abbrev = 40;
3851        }
3852        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3853                options->a_prefix = optarg;
3854                return argcount;
3855        }
3856        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3857                options->b_prefix = optarg;
3858                return argcount;
3859        }
3860        else if (!strcmp(arg, "--no-prefix"))
3861                options->a_prefix = options->b_prefix = "";
3862        else if (opt_arg(arg, '\0', "inter-hunk-context",
3863                         &options->interhunkcontext))
3864                ;
3865        else if (!strcmp(arg, "-W"))
3866                DIFF_OPT_SET(options, FUNCCONTEXT);
3867        else if (!strcmp(arg, "--function-context"))
3868                DIFF_OPT_SET(options, FUNCCONTEXT);
3869        else if (!strcmp(arg, "--no-function-context"))
3870                DIFF_OPT_CLR(options, FUNCCONTEXT);
3871        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3872                options->file = fopen(optarg, "w");
3873                if (!options->file)
3874                        die_errno("Could not open '%s'", optarg);
3875                options->close_file = 1;
3876                return argcount;
3877        } else
3878                return 0;
3879        return 1;
3880}
3881
3882int parse_rename_score(const char **cp_p)
3883{
3884        unsigned long num, scale;
3885        int ch, dot;
3886        const char *cp = *cp_p;
3887
3888        num = 0;
3889        scale = 1;
3890        dot = 0;
3891        for (;;) {
3892                ch = *cp;
3893                if ( !dot && ch == '.' ) {
3894                        scale = 1;
3895                        dot = 1;
3896                } else if ( ch == '%' ) {
3897                        scale = dot ? scale*100 : 100;
3898                        cp++;   /* % is always at the end */
3899                        break;
3900                } else if ( ch >= '0' && ch <= '9' ) {
3901                        if ( scale < 100000 ) {
3902                                scale *= 10;
3903                                num = (num*10) + (ch-'0');
3904                        }
3905                } else {
3906                        break;
3907                }
3908                cp++;
3909        }
3910        *cp_p = cp;
3911
3912        /* user says num divided by scale and we say internally that
3913         * is MAX_SCORE * num / scale.
3914         */
3915        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3916}
3917
3918static int diff_scoreopt_parse(const char *opt)
3919{
3920        int opt1, opt2, cmd;
3921
3922        if (*opt++ != '-')
3923                return -1;
3924        cmd = *opt++;
3925        if (cmd == '-') {
3926                /* convert the long-form arguments into short-form versions */
3927                if (skip_prefix(opt, "break-rewrites", &opt)) {
3928                        if (*opt == 0 || *opt++ == '=')
3929                                cmd = 'B';
3930                } else if (skip_prefix(opt, "find-copies", &opt)) {
3931                        if (*opt == 0 || *opt++ == '=')
3932                                cmd = 'C';
3933                } else if (skip_prefix(opt, "find-renames", &opt)) {
3934                        if (*opt == 0 || *opt++ == '=')
3935                                cmd = 'M';
3936                }
3937        }
3938        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3939                return -1; /* that is not a -M, -C, or -B option */
3940
3941        opt1 = parse_rename_score(&opt);
3942        if (cmd != 'B')
3943                opt2 = 0;
3944        else {
3945                if (*opt == 0)
3946                        opt2 = 0;
3947                else if (*opt != '/')
3948                        return -1; /* we expect -B80/99 or -B80 */
3949                else {
3950                        opt++;
3951                        opt2 = parse_rename_score(&opt);
3952                }
3953        }
3954        if (*opt != 0)
3955                return -1;
3956        return opt1 | (opt2 << 16);
3957}
3958
3959struct diff_queue_struct diff_queued_diff;
3960
3961void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3962{
3963        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
3964        queue->queue[queue->nr++] = dp;
3965}
3966
3967struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3968                                 struct diff_filespec *one,
3969                                 struct diff_filespec *two)
3970{
3971        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3972        dp->one = one;
3973        dp->two = two;
3974        if (queue)
3975                diff_q(queue, dp);
3976        return dp;
3977}
3978
3979void diff_free_filepair(struct diff_filepair *p)
3980{
3981        free_filespec(p->one);
3982        free_filespec(p->two);
3983        free(p);
3984}
3985
3986/* This is different from find_unique_abbrev() in that
3987 * it stuffs the result with dots for alignment.
3988 */
3989const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3990{
3991        int abblen;
3992        const char *abbrev;
3993        if (len == 40)
3994                return sha1_to_hex(sha1);
3995
3996        abbrev = find_unique_abbrev(sha1, len);
3997        abblen = strlen(abbrev);
3998        if (abblen < 37) {
3999                static char hex[41];
4000                if (len < abblen && abblen <= len + 2)
4001                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
4002                else
4003                        sprintf(hex, "%s...", abbrev);
4004                return hex;
4005        }
4006        return sha1_to_hex(sha1);
4007}
4008
4009static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4010{
4011        int line_termination = opt->line_termination;
4012        int inter_name_termination = line_termination ? '\t' : '\0';
4013
4014        fprintf(opt->file, "%s", diff_line_prefix(opt));
4015        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4016                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4017                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4018                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4019        }
4020        if (p->score) {
4021                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4022                        inter_name_termination);
4023        } else {
4024                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4025        }
4026
4027        if (p->status == DIFF_STATUS_COPIED ||
4028            p->status == DIFF_STATUS_RENAMED) {
4029                const char *name_a, *name_b;
4030                name_a = p->one->path;
4031                name_b = p->two->path;
4032                strip_prefix(opt->prefix_length, &name_a, &name_b);
4033                write_name_quoted(name_a, opt->file, inter_name_termination);
4034                write_name_quoted(name_b, opt->file, line_termination);
4035        } else {
4036                const char *name_a, *name_b;
4037                name_a = p->one->mode ? p->one->path : p->two->path;
4038                name_b = NULL;
4039                strip_prefix(opt->prefix_length, &name_a, &name_b);
4040                write_name_quoted(name_a, opt->file, line_termination);
4041        }
4042}
4043
4044int diff_unmodified_pair(struct diff_filepair *p)
4045{
4046        /* This function is written stricter than necessary to support
4047         * the currently implemented transformers, but the idea is to
4048         * let transformers to produce diff_filepairs any way they want,
4049         * and filter and clean them up here before producing the output.
4050         */
4051        struct diff_filespec *one = p->one, *two = p->two;
4052
4053        if (DIFF_PAIR_UNMERGED(p))
4054                return 0; /* unmerged is interesting */
4055
4056        /* deletion, addition, mode or type change
4057         * and rename are all interesting.
4058         */
4059        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4060            DIFF_PAIR_MODE_CHANGED(p) ||
4061            strcmp(one->path, two->path))
4062                return 0;
4063
4064        /* both are valid and point at the same path.  that is, we are
4065         * dealing with a change.
4066         */
4067        if (one->sha1_valid && two->sha1_valid &&
4068            !hashcmp(one->sha1, two->sha1) &&
4069            !one->dirty_submodule && !two->dirty_submodule)
4070                return 1; /* no change */
4071        if (!one->sha1_valid && !two->sha1_valid)
4072                return 1; /* both look at the same file on the filesystem. */
4073        return 0;
4074}
4075
4076static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4077{
4078        if (diff_unmodified_pair(p))
4079                return;
4080
4081        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4082            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4083                return; /* no tree diffs in patch format */
4084
4085        run_diff(p, o);
4086}
4087
4088static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4089                            struct diffstat_t *diffstat)
4090{
4091        if (diff_unmodified_pair(p))
4092                return;
4093
4094        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4095            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4096                return; /* no useful stat for tree diffs */
4097
4098        run_diffstat(p, o, diffstat);
4099}
4100
4101static void diff_flush_checkdiff(struct diff_filepair *p,
4102                struct diff_options *o)
4103{
4104        if (diff_unmodified_pair(p))
4105                return;
4106
4107        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4108            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4109                return; /* nothing to check in tree diffs */
4110
4111        run_checkdiff(p, o);
4112}
4113
4114int diff_queue_is_empty(void)
4115{
4116        struct diff_queue_struct *q = &diff_queued_diff;
4117        int i;
4118        for (i = 0; i < q->nr; i++)
4119                if (!diff_unmodified_pair(q->queue[i]))
4120                        return 0;
4121        return 1;
4122}
4123
4124#if DIFF_DEBUG
4125void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4126{
4127        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4128                x, one ? one : "",
4129                s->path,
4130                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4131                s->mode,
4132                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4133        fprintf(stderr, "queue[%d] %s size %lu\n",
4134                x, one ? one : "",
4135                s->size);
4136}
4137
4138void diff_debug_filepair(const struct diff_filepair *p, int i)
4139{
4140        diff_debug_filespec(p->one, i, "one");
4141        diff_debug_filespec(p->two, i, "two");
4142        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4143                p->score, p->status ? p->status : '?',
4144                p->one->rename_used, p->broken_pair);
4145}
4146
4147void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4148{
4149        int i;
4150        if (msg)
4151                fprintf(stderr, "%s\n", msg);
4152        fprintf(stderr, "q->nr = %d\n", q->nr);
4153        for (i = 0; i < q->nr; i++) {
4154                struct diff_filepair *p = q->queue[i];
4155                diff_debug_filepair(p, i);
4156        }
4157}
4158#endif
4159
4160static void diff_resolve_rename_copy(void)
4161{
4162        int i;
4163        struct diff_filepair *p;
4164        struct diff_queue_struct *q = &diff_queued_diff;
4165
4166        diff_debug_queue("resolve-rename-copy", q);
4167
4168        for (i = 0; i < q->nr; i++) {
4169                p = q->queue[i];
4170                p->status = 0; /* undecided */
4171                if (DIFF_PAIR_UNMERGED(p))
4172                        p->status = DIFF_STATUS_UNMERGED;
4173                else if (!DIFF_FILE_VALID(p->one))
4174                        p->status = DIFF_STATUS_ADDED;
4175                else if (!DIFF_FILE_VALID(p->two))
4176                        p->status = DIFF_STATUS_DELETED;
4177                else if (DIFF_PAIR_TYPE_CHANGED(p))
4178                        p->status = DIFF_STATUS_TYPE_CHANGED;
4179
4180                /* from this point on, we are dealing with a pair
4181                 * whose both sides are valid and of the same type, i.e.
4182                 * either in-place edit or rename/copy edit.
4183                 */
4184                else if (DIFF_PAIR_RENAME(p)) {
4185                        /*
4186                         * A rename might have re-connected a broken
4187                         * pair up, causing the pathnames to be the
4188                         * same again. If so, that's not a rename at
4189                         * all, just a modification..
4190                         *
4191                         * Otherwise, see if this source was used for
4192                         * multiple renames, in which case we decrement
4193                         * the count, and call it a copy.
4194                         */
4195                        if (!strcmp(p->one->path, p->two->path))
4196                                p->status = DIFF_STATUS_MODIFIED;
4197                        else if (--p->one->rename_used > 0)
4198                                p->status = DIFF_STATUS_COPIED;
4199                        else
4200                                p->status = DIFF_STATUS_RENAMED;
4201                }
4202                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4203                         p->one->mode != p->two->mode ||
4204                         p->one->dirty_submodule ||
4205                         p->two->dirty_submodule ||
4206                         is_null_sha1(p->one->sha1))
4207                        p->status = DIFF_STATUS_MODIFIED;
4208                else {
4209                        /* This is a "no-change" entry and should not
4210                         * happen anymore, but prepare for broken callers.
4211                         */
4212                        error("feeding unmodified %s to diffcore",
4213                              p->one->path);
4214                        p->status = DIFF_STATUS_UNKNOWN;
4215                }
4216        }
4217        diff_debug_queue("resolve-rename-copy done", q);
4218}
4219
4220static int check_pair_status(struct diff_filepair *p)
4221{
4222        switch (p->status) {
4223        case DIFF_STATUS_UNKNOWN:
4224                return 0;
4225        case 0:
4226                die("internal error in diff-resolve-rename-copy");
4227        default:
4228                return 1;
4229        }
4230}
4231
4232static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4233{
4234        int fmt = opt->output_format;
4235
4236        if (fmt & DIFF_FORMAT_CHECKDIFF)
4237                diff_flush_checkdiff(p, opt);
4238        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4239                diff_flush_raw(p, opt);
4240        else if (fmt & DIFF_FORMAT_NAME) {
4241                const char *name_a, *name_b;
4242                name_a = p->two->path;
4243                name_b = NULL;
4244                strip_prefix(opt->prefix_length, &name_a, &name_b);
4245                write_name_quoted(name_a, opt->file, opt->line_termination);
4246        }
4247}
4248
4249static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4250{
4251        if (fs->mode)
4252                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4253        else
4254                fprintf(file, " %s ", newdelete);
4255        write_name_quoted(fs->path, file, '\n');
4256}
4257
4258
4259static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4260                const char *line_prefix)
4261{
4262        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4263                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4264                        p->two->mode, show_name ? ' ' : '\n');
4265                if (show_name) {
4266                        write_name_quoted(p->two->path, file, '\n');
4267                }
4268        }
4269}
4270
4271static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4272                        const char *line_prefix)
4273{
4274        char *names = pprint_rename(p->one->path, p->two->path);
4275
4276        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4277        free(names);
4278        show_mode_change(file, p, 0, line_prefix);
4279}
4280
4281static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4282{
4283        FILE *file = opt->file;
4284        const char *line_prefix = diff_line_prefix(opt);
4285
4286        switch(p->status) {
4287        case DIFF_STATUS_DELETED:
4288                fputs(line_prefix, file);
4289                show_file_mode_name(file, "delete", p->one);
4290                break;
4291        case DIFF_STATUS_ADDED:
4292                fputs(line_prefix, file);
4293                show_file_mode_name(file, "create", p->two);
4294                break;
4295        case DIFF_STATUS_COPIED:
4296                fputs(line_prefix, file);
4297                show_rename_copy(file, "copy", p, line_prefix);
4298                break;
4299        case DIFF_STATUS_RENAMED:
4300                fputs(line_prefix, file);
4301                show_rename_copy(file, "rename", p, line_prefix);
4302                break;
4303        default:
4304                if (p->score) {
4305                        fprintf(file, "%s rewrite ", line_prefix);
4306                        write_name_quoted(p->two->path, file, ' ');
4307                        fprintf(file, "(%d%%)\n", similarity_index(p));
4308                }
4309                show_mode_change(file, p, !p->score, line_prefix);
4310                break;
4311        }
4312}
4313
4314struct patch_id_t {
4315        git_SHA_CTX *ctx;
4316        int patchlen;
4317};
4318
4319static int remove_space(char *line, int len)
4320{
4321        int i;
4322        char *dst = line;
4323        unsigned char c;
4324
4325        for (i = 0; i < len; i++)
4326                if (!isspace((c = line[i])))
4327                        *dst++ = c;
4328
4329        return dst - line;
4330}
4331
4332static void patch_id_consume(void *priv, char *line, unsigned long len)
4333{
4334        struct patch_id_t *data = priv;
4335        int new_len;
4336
4337        /* Ignore line numbers when computing the SHA1 of the patch */
4338        if (starts_with(line, "@@ -"))
4339                return;
4340
4341        new_len = remove_space(line, len);
4342
4343        git_SHA1_Update(data->ctx, line, new_len);
4344        data->patchlen += new_len;
4345}
4346
4347/* returns 0 upon success, and writes result into sha1 */
4348static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4349{
4350        struct diff_queue_struct *q = &diff_queued_diff;
4351        int i;
4352        git_SHA_CTX ctx;
4353        struct patch_id_t data;
4354        char buffer[PATH_MAX * 4 + 20];
4355
4356        git_SHA1_Init(&ctx);
4357        memset(&data, 0, sizeof(struct patch_id_t));
4358        data.ctx = &ctx;
4359
4360        for (i = 0; i < q->nr; i++) {
4361                xpparam_t xpp;
4362                xdemitconf_t xecfg;
4363                mmfile_t mf1, mf2;
4364                struct diff_filepair *p = q->queue[i];
4365                int len1, len2;
4366
4367                memset(&xpp, 0, sizeof(xpp));
4368                memset(&xecfg, 0, sizeof(xecfg));
4369                if (p->status == 0)
4370                        return error("internal diff status error");
4371                if (p->status == DIFF_STATUS_UNKNOWN)
4372                        continue;
4373                if (diff_unmodified_pair(p))
4374                        continue;
4375                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4376                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4377                        continue;
4378                if (DIFF_PAIR_UNMERGED(p))
4379                        continue;
4380
4381                diff_fill_sha1_info(p->one);
4382                diff_fill_sha1_info(p->two);
4383                if (fill_mmfile(&mf1, p->one) < 0 ||
4384                                fill_mmfile(&mf2, p->two) < 0)
4385                        return error("unable to read files to diff");
4386
4387                len1 = remove_space(p->one->path, strlen(p->one->path));
4388                len2 = remove_space(p->two->path, strlen(p->two->path));
4389                if (p->one->mode == 0)
4390                        len1 = snprintf(buffer, sizeof(buffer),
4391                                        "diff--gita/%.*sb/%.*s"
4392                                        "newfilemode%06o"
4393                                        "---/dev/null"
4394                                        "+++b/%.*s",
4395                                        len1, p->one->path,
4396                                        len2, p->two->path,
4397                                        p->two->mode,
4398                                        len2, p->two->path);
4399                else if (p->two->mode == 0)
4400                        len1 = snprintf(buffer, sizeof(buffer),
4401                                        "diff--gita/%.*sb/%.*s"
4402                                        "deletedfilemode%06o"
4403                                        "---a/%.*s"
4404                                        "+++/dev/null",
4405                                        len1, p->one->path,
4406                                        len2, p->two->path,
4407                                        p->one->mode,
4408                                        len1, p->one->path);
4409                else
4410                        len1 = snprintf(buffer, sizeof(buffer),
4411                                        "diff--gita/%.*sb/%.*s"
4412                                        "---a/%.*s"
4413                                        "+++b/%.*s",
4414                                        len1, p->one->path,
4415                                        len2, p->two->path,
4416                                        len1, p->one->path,
4417                                        len2, p->two->path);
4418                git_SHA1_Update(&ctx, buffer, len1);
4419
4420                if (diff_filespec_is_binary(p->one) ||
4421                    diff_filespec_is_binary(p->two)) {
4422                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4423                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4424                        continue;
4425                }
4426
4427                xpp.flags = 0;
4428                xecfg.ctxlen = 3;
4429                xecfg.flags = 0;
4430                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4431                              &xpp, &xecfg);
4432        }
4433
4434        git_SHA1_Final(sha1, &ctx);
4435        return 0;
4436}
4437
4438int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4439{
4440        struct diff_queue_struct *q = &diff_queued_diff;
4441        int i;
4442        int result = diff_get_patch_id(options, sha1);
4443
4444        for (i = 0; i < q->nr; i++)
4445                diff_free_filepair(q->queue[i]);
4446
4447        free(q->queue);
4448        DIFF_QUEUE_CLEAR(q);
4449
4450        return result;
4451}
4452
4453static int is_summary_empty(const struct diff_queue_struct *q)
4454{
4455        int i;
4456
4457        for (i = 0; i < q->nr; i++) {
4458                const struct diff_filepair *p = q->queue[i];
4459
4460                switch (p->status) {
4461                case DIFF_STATUS_DELETED:
4462                case DIFF_STATUS_ADDED:
4463                case DIFF_STATUS_COPIED:
4464                case DIFF_STATUS_RENAMED:
4465                        return 0;
4466                default:
4467                        if (p->score)
4468                                return 0;
4469                        if (p->one->mode && p->two->mode &&
4470                            p->one->mode != p->two->mode)
4471                                return 0;
4472                        break;
4473                }
4474        }
4475        return 1;
4476}
4477
4478static const char rename_limit_warning[] =
4479"inexact rename detection was skipped due to too many files.";
4480
4481static const char degrade_cc_to_c_warning[] =
4482"only found copies from modified paths due to too many files.";
4483
4484static const char rename_limit_advice[] =
4485"you may want to set your %s variable to at least "
4486"%d and retry the command.";
4487
4488void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4489{
4490        if (degraded_cc)
4491                warning(degrade_cc_to_c_warning);
4492        else if (needed)
4493                warning(rename_limit_warning);
4494        else
4495                return;
4496        if (0 < needed && needed < 32767)
4497                warning(rename_limit_advice, varname, needed);
4498}
4499
4500void diff_flush(struct diff_options *options)
4501{
4502        struct diff_queue_struct *q = &diff_queued_diff;
4503        int i, output_format = options->output_format;
4504        int separator = 0;
4505        int dirstat_by_line = 0;
4506
4507        /*
4508         * Order: raw, stat, summary, patch
4509         * or:    name/name-status/checkdiff (other bits clear)
4510         */
4511        if (!q->nr)
4512                goto free_queue;
4513
4514        if (output_format & (DIFF_FORMAT_RAW |
4515                             DIFF_FORMAT_NAME |
4516                             DIFF_FORMAT_NAME_STATUS |
4517                             DIFF_FORMAT_CHECKDIFF)) {
4518                for (i = 0; i < q->nr; i++) {
4519                        struct diff_filepair *p = q->queue[i];
4520                        if (check_pair_status(p))
4521                                flush_one_pair(p, options);
4522                }
4523                separator++;
4524        }
4525
4526        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4527                dirstat_by_line = 1;
4528
4529        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4530            dirstat_by_line) {
4531                struct diffstat_t diffstat;
4532
4533                memset(&diffstat, 0, sizeof(struct diffstat_t));
4534                for (i = 0; i < q->nr; i++) {
4535                        struct diff_filepair *p = q->queue[i];
4536                        if (check_pair_status(p))
4537                                diff_flush_stat(p, options, &diffstat);
4538                }
4539                if (output_format & DIFF_FORMAT_NUMSTAT)
4540                        show_numstat(&diffstat, options);
4541                if (output_format & DIFF_FORMAT_DIFFSTAT)
4542                        show_stats(&diffstat, options);
4543                if (output_format & DIFF_FORMAT_SHORTSTAT)
4544                        show_shortstats(&diffstat, options);
4545                if (output_format & DIFF_FORMAT_DIRSTAT)
4546                        show_dirstat_by_line(&diffstat, options);
4547                free_diffstat_info(&diffstat);
4548                separator++;
4549        }
4550        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4551                show_dirstat(options);
4552
4553        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4554                for (i = 0; i < q->nr; i++) {
4555                        diff_summary(options, q->queue[i]);
4556                }
4557                separator++;
4558        }
4559
4560        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4561            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4562            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4563                /*
4564                 * run diff_flush_patch for the exit status. setting
4565                 * options->file to /dev/null should be safe, because we
4566                 * aren't supposed to produce any output anyway.
4567                 */
4568                if (options->close_file)
4569                        fclose(options->file);
4570                options->file = fopen("/dev/null", "w");
4571                if (!options->file)
4572                        die_errno("Could not open /dev/null");
4573                options->close_file = 1;
4574                for (i = 0; i < q->nr; i++) {
4575                        struct diff_filepair *p = q->queue[i];
4576                        if (check_pair_status(p))
4577                                diff_flush_patch(p, options);
4578                        if (options->found_changes)
4579                                break;
4580                }
4581        }
4582
4583        if (output_format & DIFF_FORMAT_PATCH) {
4584                if (separator) {
4585                        fprintf(options->file, "%s%c",
4586                                diff_line_prefix(options),
4587                                options->line_termination);
4588                        if (options->stat_sep) {
4589                                /* attach patch instead of inline */
4590                                fputs(options->stat_sep, options->file);
4591                        }
4592                }
4593
4594                for (i = 0; i < q->nr; i++) {
4595                        struct diff_filepair *p = q->queue[i];
4596                        if (check_pair_status(p))
4597                                diff_flush_patch(p, options);
4598                }
4599        }
4600
4601        if (output_format & DIFF_FORMAT_CALLBACK)
4602                options->format_callback(q, options, options->format_callback_data);
4603
4604        for (i = 0; i < q->nr; i++)
4605                diff_free_filepair(q->queue[i]);
4606free_queue:
4607        free(q->queue);
4608        DIFF_QUEUE_CLEAR(q);
4609        if (options->close_file)
4610                fclose(options->file);
4611
4612        /*
4613         * Report the content-level differences with HAS_CHANGES;
4614         * diff_addremove/diff_change does not set the bit when
4615         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4616         */
4617        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4618                if (options->found_changes)
4619                        DIFF_OPT_SET(options, HAS_CHANGES);
4620                else
4621                        DIFF_OPT_CLR(options, HAS_CHANGES);
4622        }
4623}
4624
4625static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4626{
4627        return (((p->status == DIFF_STATUS_MODIFIED) &&
4628                 ((p->score &&
4629                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4630                  (!p->score &&
4631                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4632                ((p->status != DIFF_STATUS_MODIFIED) &&
4633                 filter_bit_tst(p->status, options)));
4634}
4635
4636static void diffcore_apply_filter(struct diff_options *options)
4637{
4638        int i;
4639        struct diff_queue_struct *q = &diff_queued_diff;
4640        struct diff_queue_struct outq;
4641
4642        DIFF_QUEUE_CLEAR(&outq);
4643
4644        if (!options->filter)
4645                return;
4646
4647        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4648                int found;
4649                for (i = found = 0; !found && i < q->nr; i++) {
4650                        if (match_filter(options, q->queue[i]))
4651                                found++;
4652                }
4653                if (found)
4654                        return;
4655
4656                /* otherwise we will clear the whole queue
4657                 * by copying the empty outq at the end of this
4658                 * function, but first clear the current entries
4659                 * in the queue.
4660                 */
4661                for (i = 0; i < q->nr; i++)
4662                        diff_free_filepair(q->queue[i]);
4663        }
4664        else {
4665                /* Only the matching ones */
4666                for (i = 0; i < q->nr; i++) {
4667                        struct diff_filepair *p = q->queue[i];
4668                        if (match_filter(options, p))
4669                                diff_q(&outq, p);
4670                        else
4671                                diff_free_filepair(p);
4672                }
4673        }
4674        free(q->queue);
4675        *q = outq;
4676}
4677
4678/* Check whether two filespecs with the same mode and size are identical */
4679static int diff_filespec_is_identical(struct diff_filespec *one,
4680                                      struct diff_filespec *two)
4681{
4682        if (S_ISGITLINK(one->mode))
4683                return 0;
4684        if (diff_populate_filespec(one, 0))
4685                return 0;
4686        if (diff_populate_filespec(two, 0))
4687                return 0;
4688        return !memcmp(one->data, two->data, one->size);
4689}
4690
4691static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4692{
4693        if (p->done_skip_stat_unmatch)
4694                return p->skip_stat_unmatch_result;
4695
4696        p->done_skip_stat_unmatch = 1;
4697        p->skip_stat_unmatch_result = 0;
4698        /*
4699         * 1. Entries that come from stat info dirtiness
4700         *    always have both sides (iow, not create/delete),
4701         *    one side of the object name is unknown, with
4702         *    the same mode and size.  Keep the ones that
4703         *    do not match these criteria.  They have real
4704         *    differences.
4705         *
4706         * 2. At this point, the file is known to be modified,
4707         *    with the same mode and size, and the object
4708         *    name of one side is unknown.  Need to inspect
4709         *    the identical contents.
4710         */
4711        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4712            !DIFF_FILE_VALID(p->two) ||
4713            (p->one->sha1_valid && p->two->sha1_valid) ||
4714            (p->one->mode != p->two->mode) ||
4715            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4716            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4717            (p->one->size != p->two->size) ||
4718            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4719                p->skip_stat_unmatch_result = 1;
4720        return p->skip_stat_unmatch_result;
4721}
4722
4723static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4724{
4725        int i;
4726        struct diff_queue_struct *q = &diff_queued_diff;
4727        struct diff_queue_struct outq;
4728        DIFF_QUEUE_CLEAR(&outq);
4729
4730        for (i = 0; i < q->nr; i++) {
4731                struct diff_filepair *p = q->queue[i];
4732
4733                if (diff_filespec_check_stat_unmatch(p))
4734                        diff_q(&outq, p);
4735                else {
4736                        /*
4737                         * The caller can subtract 1 from skip_stat_unmatch
4738                         * to determine how many paths were dirty only
4739                         * due to stat info mismatch.
4740                         */
4741                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4742                                diffopt->skip_stat_unmatch++;
4743                        diff_free_filepair(p);
4744                }
4745        }
4746        free(q->queue);
4747        *q = outq;
4748}
4749
4750static int diffnamecmp(const void *a_, const void *b_)
4751{
4752        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4753        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4754        const char *name_a, *name_b;
4755
4756        name_a = a->one ? a->one->path : a->two->path;
4757        name_b = b->one ? b->one->path : b->two->path;
4758        return strcmp(name_a, name_b);
4759}
4760
4761void diffcore_fix_diff_index(struct diff_options *options)
4762{
4763        struct diff_queue_struct *q = &diff_queued_diff;
4764        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4765}
4766
4767void diffcore_std(struct diff_options *options)
4768{
4769        /* NOTE please keep the following in sync with diff_tree_combined() */
4770        if (options->skip_stat_unmatch)
4771                diffcore_skip_stat_unmatch(options);
4772        if (!options->found_follow) {
4773                /* See try_to_follow_renames() in tree-diff.c */
4774                if (options->break_opt != -1)
4775                        diffcore_break(options->break_opt);
4776                if (options->detect_rename)
4777                        diffcore_rename(options);
4778                if (options->break_opt != -1)
4779                        diffcore_merge_broken();
4780        }
4781        if (options->pickaxe)
4782                diffcore_pickaxe(options);
4783        if (options->orderfile)
4784                diffcore_order(options->orderfile);
4785        if (!options->found_follow)
4786                /* See try_to_follow_renames() in tree-diff.c */
4787                diff_resolve_rename_copy();
4788        diffcore_apply_filter(options);
4789
4790        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4791                DIFF_OPT_SET(options, HAS_CHANGES);
4792        else
4793                DIFF_OPT_CLR(options, HAS_CHANGES);
4794
4795        options->found_follow = 0;
4796}
4797
4798int diff_result_code(struct diff_options *opt, int status)
4799{
4800        int result = 0;
4801
4802        diff_warn_rename_limit("diff.renameLimit",
4803                               opt->needed_rename_limit,
4804                               opt->degraded_cc_to_c);
4805        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4806            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4807                return status;
4808        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4809            DIFF_OPT_TST(opt, HAS_CHANGES))
4810                result |= 01;
4811        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4812            DIFF_OPT_TST(opt, CHECK_FAILED))
4813                result |= 02;
4814        return result;
4815}
4816
4817int diff_can_quit_early(struct diff_options *opt)
4818{
4819        return (DIFF_OPT_TST(opt, QUICK) &&
4820                !opt->filter &&
4821                DIFF_OPT_TST(opt, HAS_CHANGES));
4822}
4823
4824/*
4825 * Shall changes to this submodule be ignored?
4826 *
4827 * Submodule changes can be configured to be ignored separately for each path,
4828 * but that configuration can be overridden from the command line.
4829 */
4830static int is_submodule_ignored(const char *path, struct diff_options *options)
4831{
4832        int ignored = 0;
4833        unsigned orig_flags = options->flags;
4834        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4835                set_diffopt_flags_from_submodule_config(options, path);
4836        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4837                ignored = 1;
4838        options->flags = orig_flags;
4839        return ignored;
4840}
4841
4842void diff_addremove(struct diff_options *options,
4843                    int addremove, unsigned mode,
4844                    const unsigned char *sha1,
4845                    int sha1_valid,
4846                    const char *concatpath, unsigned dirty_submodule)
4847{
4848        struct diff_filespec *one, *two;
4849
4850        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4851                return;
4852
4853        /* This may look odd, but it is a preparation for
4854         * feeding "there are unchanged files which should
4855         * not produce diffs, but when you are doing copy
4856         * detection you would need them, so here they are"
4857         * entries to the diff-core.  They will be prefixed
4858         * with something like '=' or '*' (I haven't decided
4859         * which but should not make any difference).
4860         * Feeding the same new and old to diff_change()
4861         * also has the same effect.
4862         * Before the final output happens, they are pruned after
4863         * merged into rename/copy pairs as appropriate.
4864         */
4865        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4866                addremove = (addremove == '+' ? '-' :
4867                             addremove == '-' ? '+' : addremove);
4868
4869        if (options->prefix &&
4870            strncmp(concatpath, options->prefix, options->prefix_length))
4871                return;
4872
4873        one = alloc_filespec(concatpath);
4874        two = alloc_filespec(concatpath);
4875
4876        if (addremove != '+')
4877                fill_filespec(one, sha1, sha1_valid, mode);
4878        if (addremove != '-') {
4879                fill_filespec(two, sha1, sha1_valid, mode);
4880                two->dirty_submodule = dirty_submodule;
4881        }
4882
4883        diff_queue(&diff_queued_diff, one, two);
4884        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4885                DIFF_OPT_SET(options, HAS_CHANGES);
4886}
4887
4888void diff_change(struct diff_options *options,
4889                 unsigned old_mode, unsigned new_mode,
4890                 const unsigned char *old_sha1,
4891                 const unsigned char *new_sha1,
4892                 int old_sha1_valid, int new_sha1_valid,
4893                 const char *concatpath,
4894                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4895{
4896        struct diff_filespec *one, *two;
4897        struct diff_filepair *p;
4898
4899        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4900            is_submodule_ignored(concatpath, options))
4901                return;
4902
4903        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4904                unsigned tmp;
4905                const unsigned char *tmp_c;
4906                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4907                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4908                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4909                        new_sha1_valid = tmp;
4910                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4911                        new_dirty_submodule = tmp;
4912        }
4913
4914        if (options->prefix &&
4915            strncmp(concatpath, options->prefix, options->prefix_length))
4916                return;
4917
4918        one = alloc_filespec(concatpath);
4919        two = alloc_filespec(concatpath);
4920        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4921        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4922        one->dirty_submodule = old_dirty_submodule;
4923        two->dirty_submodule = new_dirty_submodule;
4924        p = diff_queue(&diff_queued_diff, one, two);
4925
4926        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4927                return;
4928
4929        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
4930            !diff_filespec_check_stat_unmatch(p))
4931                return;
4932
4933        DIFF_OPT_SET(options, HAS_CHANGES);
4934}
4935
4936struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4937{
4938        struct diff_filepair *pair;
4939        struct diff_filespec *one, *two;
4940
4941        if (options->prefix &&
4942            strncmp(path, options->prefix, options->prefix_length))
4943                return NULL;
4944
4945        one = alloc_filespec(path);
4946        two = alloc_filespec(path);
4947        pair = diff_queue(&diff_queued_diff, one, two);
4948        pair->is_unmerged = 1;
4949        return pair;
4950}
4951
4952static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4953                size_t *outsize)
4954{
4955        struct diff_tempfile *temp;
4956        const char *argv[3];
4957        const char **arg = argv;
4958        struct child_process child = CHILD_PROCESS_INIT;
4959        struct strbuf buf = STRBUF_INIT;
4960        int err = 0;
4961
4962        temp = prepare_temp_file(spec->path, spec);
4963        *arg++ = pgm;
4964        *arg++ = temp->name;
4965        *arg = NULL;
4966
4967        child.use_shell = 1;
4968        child.argv = argv;
4969        child.out = -1;
4970        if (start_command(&child)) {
4971                remove_tempfile();
4972                return NULL;
4973        }
4974
4975        if (strbuf_read(&buf, child.out, 0) < 0)
4976                err = error("error reading from textconv command '%s'", pgm);
4977        close(child.out);
4978
4979        if (finish_command(&child) || err) {
4980                strbuf_release(&buf);
4981                remove_tempfile();
4982                return NULL;
4983        }
4984        remove_tempfile();
4985
4986        return strbuf_detach(&buf, outsize);
4987}
4988
4989size_t fill_textconv(struct userdiff_driver *driver,
4990                     struct diff_filespec *df,
4991                     char **outbuf)
4992{
4993        size_t size;
4994
4995        if (!driver || !driver->textconv) {
4996                if (!DIFF_FILE_VALID(df)) {
4997                        *outbuf = "";
4998                        return 0;
4999                }
5000                if (diff_populate_filespec(df, 0))
5001                        die("unable to read files to diff");
5002                *outbuf = df->data;
5003                return df->size;
5004        }
5005
5006        if (driver->textconv_cache && df->sha1_valid) {
5007                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5008                                          &size);
5009                if (*outbuf)
5010                        return size;
5011        }
5012
5013        *outbuf = run_textconv(driver->textconv, df, &size);
5014        if (!*outbuf)
5015                die("unable to read files to diff");
5016
5017        if (driver->textconv_cache && df->sha1_valid) {
5018                /* ignore errors, as we might be in a readonly repository */
5019                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5020                                size);
5021                /*
5022                 * we could save up changes and flush them all at the end,
5023                 * but we would need an extra call after all diffing is done.
5024                 * Since generating a cache entry is the slow path anyway,
5025                 * this extra overhead probably isn't a big deal.
5026                 */
5027                notes_cache_write(driver->textconv_cache);
5028        }
5029
5030        return size;
5031}
5032
5033void setup_diff_pager(struct diff_options *opt)
5034{
5035        /*
5036         * If the user asked for our exit code, then either they want --quiet
5037         * or --exit-code. We should definitely not bother with a pager in the
5038         * former case, as we will generate no output. Since we still properly
5039         * report our exit code even when a pager is run, we _could_ run a
5040         * pager with --exit-code. But since we have not done so historically,
5041         * and because it is easy to find people oneline advising "git diff
5042         * --exit-code" in hooks and other scripts, we do not do so.
5043         */
5044        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5045            check_pager_config("diff") != 0)
5046                setup_pager();
5047}