diff.con commit commit: do not lose SQUASH_MSG contents (b64c1e0)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18#include "string-list.h"
  19#include "argv-array.h"
  20
  21#ifdef NO_FAST_WORKING_DIRECTORY
  22#define FAST_WORKING_DIRECTORY 0
  23#else
  24#define FAST_WORKING_DIRECTORY 1
  25#endif
  26
  27static int diff_detect_rename_default;
  28static int diff_rename_limit_default = 400;
  29static int diff_suppress_blank_empty;
  30static int diff_use_color_default = -1;
  31static int diff_context_default = 3;
  32static const char *diff_word_regex_cfg;
  33static const char *external_diff_cmd_cfg;
  34static const char *diff_order_file_cfg;
  35int diff_auto_refresh_index = 1;
  36static int diff_mnemonic_prefix;
  37static int diff_no_prefix;
  38static int diff_stat_graph_width;
  39static int diff_dirstat_permille_default = 30;
  40static struct diff_options default_diff_options;
  41static long diff_algorithm;
  42
  43static char diff_colors[][COLOR_MAXLEN] = {
  44        GIT_COLOR_RESET,
  45        GIT_COLOR_NORMAL,       /* CONTEXT */
  46        GIT_COLOR_BOLD,         /* METAINFO */
  47        GIT_COLOR_CYAN,         /* FRAGINFO */
  48        GIT_COLOR_RED,          /* OLD */
  49        GIT_COLOR_GREEN,        /* NEW */
  50        GIT_COLOR_YELLOW,       /* COMMIT */
  51        GIT_COLOR_BG_RED,       /* WHITESPACE */
  52        GIT_COLOR_NORMAL,       /* FUNCINFO */
  53};
  54
  55static int parse_diff_color_slot(const char *var)
  56{
  57        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  58                return DIFF_CONTEXT;
  59        if (!strcasecmp(var, "meta"))
  60                return DIFF_METAINFO;
  61        if (!strcasecmp(var, "frag"))
  62                return DIFF_FRAGINFO;
  63        if (!strcasecmp(var, "old"))
  64                return DIFF_FILE_OLD;
  65        if (!strcasecmp(var, "new"))
  66                return DIFF_FILE_NEW;
  67        if (!strcasecmp(var, "commit"))
  68                return DIFF_COMMIT;
  69        if (!strcasecmp(var, "whitespace"))
  70                return DIFF_WHITESPACE;
  71        if (!strcasecmp(var, "func"))
  72                return DIFF_FUNCINFO;
  73        return -1;
  74}
  75
  76static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  77                                struct strbuf *errmsg)
  78{
  79        char *params_copy = xstrdup(params_string);
  80        struct string_list params = STRING_LIST_INIT_NODUP;
  81        int ret = 0;
  82        int i;
  83
  84        if (*params_copy)
  85                string_list_split_in_place(&params, params_copy, ',', -1);
  86        for (i = 0; i < params.nr; i++) {
  87                const char *p = params.items[i].string;
  88                if (!strcmp(p, "changes")) {
  89                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  90                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  91                } else if (!strcmp(p, "lines")) {
  92                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  93                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  94                } else if (!strcmp(p, "files")) {
  95                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  96                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  97                } else if (!strcmp(p, "noncumulative")) {
  98                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  99                } else if (!strcmp(p, "cumulative")) {
 100                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 101                } else if (isdigit(*p)) {
 102                        char *end;
 103                        int permille = strtoul(p, &end, 10) * 10;
 104                        if (*end == '.' && isdigit(*++end)) {
 105                                /* only use first digit */
 106                                permille += *end - '0';
 107                                /* .. and ignore any further digits */
 108                                while (isdigit(*++end))
 109                                        ; /* nothing */
 110                        }
 111                        if (!*end)
 112                                options->dirstat_permille = permille;
 113                        else {
 114                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 115                                            p);
 116                                ret++;
 117                        }
 118                } else {
 119                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 120                        ret++;
 121                }
 122
 123        }
 124        string_list_clear(&params, 0);
 125        free(params_copy);
 126        return ret;
 127}
 128
 129static int parse_submodule_params(struct diff_options *options, const char *value)
 130{
 131        if (!strcmp(value, "log"))
 132                DIFF_OPT_SET(options, SUBMODULE_LOG);
 133        else if (!strcmp(value, "short"))
 134                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 135        else
 136                return -1;
 137        return 0;
 138}
 139
 140static int git_config_rename(const char *var, const char *value)
 141{
 142        if (!value)
 143                return DIFF_DETECT_RENAME;
 144        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 145                return  DIFF_DETECT_COPY;
 146        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 147}
 148
 149long parse_algorithm_value(const char *value)
 150{
 151        if (!value)
 152                return -1;
 153        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 154                return 0;
 155        else if (!strcasecmp(value, "minimal"))
 156                return XDF_NEED_MINIMAL;
 157        else if (!strcasecmp(value, "patience"))
 158                return XDF_PATIENCE_DIFF;
 159        else if (!strcasecmp(value, "histogram"))
 160                return XDF_HISTOGRAM_DIFF;
 161        return -1;
 162}
 163
 164/*
 165 * These are to give UI layer defaults.
 166 * The core-level commands such as git-diff-files should
 167 * never be affected by the setting of diff.renames
 168 * the user happens to have in the configuration file.
 169 */
 170int git_diff_ui_config(const char *var, const char *value, void *cb)
 171{
 172        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 173                diff_use_color_default = git_config_colorbool(var, value);
 174                return 0;
 175        }
 176        if (!strcmp(var, "diff.context")) {
 177                diff_context_default = git_config_int(var, value);
 178                if (diff_context_default < 0)
 179                        return -1;
 180                return 0;
 181        }
 182        if (!strcmp(var, "diff.renames")) {
 183                diff_detect_rename_default = git_config_rename(var, value);
 184                return 0;
 185        }
 186        if (!strcmp(var, "diff.autorefreshindex")) {
 187                diff_auto_refresh_index = git_config_bool(var, value);
 188                return 0;
 189        }
 190        if (!strcmp(var, "diff.mnemonicprefix")) {
 191                diff_mnemonic_prefix = git_config_bool(var, value);
 192                return 0;
 193        }
 194        if (!strcmp(var, "diff.noprefix")) {
 195                diff_no_prefix = git_config_bool(var, value);
 196                return 0;
 197        }
 198        if (!strcmp(var, "diff.statgraphwidth")) {
 199                diff_stat_graph_width = git_config_int(var, value);
 200                return 0;
 201        }
 202        if (!strcmp(var, "diff.external"))
 203                return git_config_string(&external_diff_cmd_cfg, var, value);
 204        if (!strcmp(var, "diff.wordregex"))
 205                return git_config_string(&diff_word_regex_cfg, var, value);
 206        if (!strcmp(var, "diff.orderfile"))
 207                return git_config_pathname(&diff_order_file_cfg, var, value);
 208
 209        if (!strcmp(var, "diff.ignoresubmodules"))
 210                handle_ignore_submodules_arg(&default_diff_options, value);
 211
 212        if (!strcmp(var, "diff.submodule")) {
 213                if (parse_submodule_params(&default_diff_options, value))
 214                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 215                                value);
 216                return 0;
 217        }
 218
 219        if (!strcmp(var, "diff.algorithm")) {
 220                diff_algorithm = parse_algorithm_value(value);
 221                if (diff_algorithm < 0)
 222                        return -1;
 223                return 0;
 224        }
 225
 226        if (git_color_config(var, value, cb) < 0)
 227                return -1;
 228
 229        return git_diff_basic_config(var, value, cb);
 230}
 231
 232int git_diff_basic_config(const char *var, const char *value, void *cb)
 233{
 234        const char *name;
 235
 236        if (!strcmp(var, "diff.renamelimit")) {
 237                diff_rename_limit_default = git_config_int(var, value);
 238                return 0;
 239        }
 240
 241        if (userdiff_config(var, value) < 0)
 242                return -1;
 243
 244        if (skip_prefix(var, "diff.color.", &name) ||
 245            skip_prefix(var, "color.diff.", &name)) {
 246                int slot = parse_diff_color_slot(name);
 247                if (slot < 0)
 248                        return 0;
 249                if (!value)
 250                        return config_error_nonbool(var);
 251                return color_parse(value, diff_colors[slot]);
 252        }
 253
 254        /* like GNU diff's --suppress-blank-empty option  */
 255        if (!strcmp(var, "diff.suppressblankempty") ||
 256                        /* for backwards compatibility */
 257                        !strcmp(var, "diff.suppress-blank-empty")) {
 258                diff_suppress_blank_empty = git_config_bool(var, value);
 259                return 0;
 260        }
 261
 262        if (!strcmp(var, "diff.dirstat")) {
 263                struct strbuf errmsg = STRBUF_INIT;
 264                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 265                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 266                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 267                                errmsg.buf);
 268                strbuf_release(&errmsg);
 269                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 270                return 0;
 271        }
 272
 273        if (starts_with(var, "submodule."))
 274                return parse_submodule_config_option(var, value);
 275
 276        return git_default_config(var, value, cb);
 277}
 278
 279static char *quote_two(const char *one, const char *two)
 280{
 281        int need_one = quote_c_style(one, NULL, NULL, 1);
 282        int need_two = quote_c_style(two, NULL, NULL, 1);
 283        struct strbuf res = STRBUF_INIT;
 284
 285        if (need_one + need_two) {
 286                strbuf_addch(&res, '"');
 287                quote_c_style(one, &res, NULL, 1);
 288                quote_c_style(two, &res, NULL, 1);
 289                strbuf_addch(&res, '"');
 290        } else {
 291                strbuf_addstr(&res, one);
 292                strbuf_addstr(&res, two);
 293        }
 294        return strbuf_detach(&res, NULL);
 295}
 296
 297static const char *external_diff(void)
 298{
 299        static const char *external_diff_cmd = NULL;
 300        static int done_preparing = 0;
 301
 302        if (done_preparing)
 303                return external_diff_cmd;
 304        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 305        if (!external_diff_cmd)
 306                external_diff_cmd = external_diff_cmd_cfg;
 307        done_preparing = 1;
 308        return external_diff_cmd;
 309}
 310
 311static struct diff_tempfile {
 312        const char *name; /* filename external diff should read from */
 313        char hex[41];
 314        char mode[10];
 315        char tmp_path[PATH_MAX];
 316} diff_temp[2];
 317
 318typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 319
 320struct emit_callback {
 321        int color_diff;
 322        unsigned ws_rule;
 323        int blank_at_eof_in_preimage;
 324        int blank_at_eof_in_postimage;
 325        int lno_in_preimage;
 326        int lno_in_postimage;
 327        sane_truncate_fn truncate;
 328        const char **label_path;
 329        struct diff_words_data *diff_words;
 330        struct diff_options *opt;
 331        int *found_changesp;
 332        struct strbuf *header;
 333};
 334
 335static int count_lines(const char *data, int size)
 336{
 337        int count, ch, completely_empty = 1, nl_just_seen = 0;
 338        count = 0;
 339        while (0 < size--) {
 340                ch = *data++;
 341                if (ch == '\n') {
 342                        count++;
 343                        nl_just_seen = 1;
 344                        completely_empty = 0;
 345                }
 346                else {
 347                        nl_just_seen = 0;
 348                        completely_empty = 0;
 349                }
 350        }
 351        if (completely_empty)
 352                return 0;
 353        if (!nl_just_seen)
 354                count++; /* no trailing newline */
 355        return count;
 356}
 357
 358static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 359{
 360        if (!DIFF_FILE_VALID(one)) {
 361                mf->ptr = (char *)""; /* does not matter */
 362                mf->size = 0;
 363                return 0;
 364        }
 365        else if (diff_populate_filespec(one, 0))
 366                return -1;
 367
 368        mf->ptr = one->data;
 369        mf->size = one->size;
 370        return 0;
 371}
 372
 373/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 374static unsigned long diff_filespec_size(struct diff_filespec *one)
 375{
 376        if (!DIFF_FILE_VALID(one))
 377                return 0;
 378        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 379        return one->size;
 380}
 381
 382static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 383{
 384        char *ptr = mf->ptr;
 385        long size = mf->size;
 386        int cnt = 0;
 387
 388        if (!size)
 389                return cnt;
 390        ptr += size - 1; /* pointing at the very end */
 391        if (*ptr != '\n')
 392                ; /* incomplete line */
 393        else
 394                ptr--; /* skip the last LF */
 395        while (mf->ptr < ptr) {
 396                char *prev_eol;
 397                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 398                        if (*prev_eol == '\n')
 399                                break;
 400                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 401                        break;
 402                cnt++;
 403                ptr = prev_eol - 1;
 404        }
 405        return cnt;
 406}
 407
 408static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 409                               struct emit_callback *ecbdata)
 410{
 411        int l1, l2, at;
 412        unsigned ws_rule = ecbdata->ws_rule;
 413        l1 = count_trailing_blank(mf1, ws_rule);
 414        l2 = count_trailing_blank(mf2, ws_rule);
 415        if (l2 <= l1) {
 416                ecbdata->blank_at_eof_in_preimage = 0;
 417                ecbdata->blank_at_eof_in_postimage = 0;
 418                return;
 419        }
 420        at = count_lines(mf1->ptr, mf1->size);
 421        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 422
 423        at = count_lines(mf2->ptr, mf2->size);
 424        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 425}
 426
 427static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 428                        int first, const char *line, int len)
 429{
 430        int has_trailing_newline, has_trailing_carriage_return;
 431        int nofirst;
 432        FILE *file = o->file;
 433
 434        fputs(diff_line_prefix(o), file);
 435
 436        if (len == 0) {
 437                has_trailing_newline = (first == '\n');
 438                has_trailing_carriage_return = (!has_trailing_newline &&
 439                                                (first == '\r'));
 440                nofirst = has_trailing_newline || has_trailing_carriage_return;
 441        } else {
 442                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 443                if (has_trailing_newline)
 444                        len--;
 445                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 446                if (has_trailing_carriage_return)
 447                        len--;
 448                nofirst = 0;
 449        }
 450
 451        if (len || !nofirst) {
 452                fputs(set, file);
 453                if (!nofirst)
 454                        fputc(first, file);
 455                fwrite(line, len, 1, file);
 456                fputs(reset, file);
 457        }
 458        if (has_trailing_carriage_return)
 459                fputc('\r', file);
 460        if (has_trailing_newline)
 461                fputc('\n', file);
 462}
 463
 464static void emit_line(struct diff_options *o, const char *set, const char *reset,
 465                      const char *line, int len)
 466{
 467        emit_line_0(o, set, reset, line[0], line+1, len-1);
 468}
 469
 470static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 471{
 472        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 473              ecbdata->blank_at_eof_in_preimage &&
 474              ecbdata->blank_at_eof_in_postimage &&
 475              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 476              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 477                return 0;
 478        return ws_blank_line(line, len, ecbdata->ws_rule);
 479}
 480
 481static void emit_line_checked(const char *reset,
 482                              struct emit_callback *ecbdata,
 483                              const char *line, int len,
 484                              enum color_diff color,
 485                              unsigned ws_error_highlight,
 486                              char sign)
 487{
 488        const char *set = diff_get_color(ecbdata->color_diff, color);
 489        const char *ws = NULL;
 490
 491        if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 492                ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 493                if (!*ws)
 494                        ws = NULL;
 495        }
 496
 497        if (!ws)
 498                emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 499        else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 500                /* Blank line at EOF - paint '+' as well */
 501                emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 502        else {
 503                /* Emit just the prefix, then the rest. */
 504                emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 505                ws_check_emit(line, len, ecbdata->ws_rule,
 506                              ecbdata->opt->file, set, reset, ws);
 507        }
 508}
 509
 510static void emit_add_line(const char *reset,
 511                          struct emit_callback *ecbdata,
 512                          const char *line, int len)
 513{
 514        emit_line_checked(reset, ecbdata, line, len,
 515                          DIFF_FILE_NEW, WSEH_NEW, '+');
 516}
 517
 518static void emit_del_line(const char *reset,
 519                          struct emit_callback *ecbdata,
 520                          const char *line, int len)
 521{
 522        emit_line_checked(reset, ecbdata, line, len,
 523                          DIFF_FILE_OLD, WSEH_OLD, '-');
 524}
 525
 526static void emit_context_line(const char *reset,
 527                              struct emit_callback *ecbdata,
 528                              const char *line, int len)
 529{
 530        emit_line_checked(reset, ecbdata, line, len,
 531                          DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 532}
 533
 534static void emit_hunk_header(struct emit_callback *ecbdata,
 535                             const char *line, int len)
 536{
 537        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 538        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 539        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 540        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 541        static const char atat[2] = { '@', '@' };
 542        const char *cp, *ep;
 543        struct strbuf msgbuf = STRBUF_INIT;
 544        int org_len = len;
 545        int i = 1;
 546
 547        /*
 548         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 549         * it always is at least 10 bytes long.
 550         */
 551        if (len < 10 ||
 552            memcmp(line, atat, 2) ||
 553            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 554                emit_line(ecbdata->opt, context, reset, line, len);
 555                return;
 556        }
 557        ep += 2; /* skip over @@ */
 558
 559        /* The hunk header in fraginfo color */
 560        strbuf_addstr(&msgbuf, frag);
 561        strbuf_add(&msgbuf, line, ep - line);
 562        strbuf_addstr(&msgbuf, reset);
 563
 564        /*
 565         * trailing "\r\n"
 566         */
 567        for ( ; i < 3; i++)
 568                if (line[len - i] == '\r' || line[len - i] == '\n')
 569                        len--;
 570
 571        /* blank before the func header */
 572        for (cp = ep; ep - line < len; ep++)
 573                if (*ep != ' ' && *ep != '\t')
 574                        break;
 575        if (ep != cp) {
 576                strbuf_addstr(&msgbuf, context);
 577                strbuf_add(&msgbuf, cp, ep - cp);
 578                strbuf_addstr(&msgbuf, reset);
 579        }
 580
 581        if (ep < line + len) {
 582                strbuf_addstr(&msgbuf, func);
 583                strbuf_add(&msgbuf, ep, line + len - ep);
 584                strbuf_addstr(&msgbuf, reset);
 585        }
 586
 587        strbuf_add(&msgbuf, line + len, org_len - len);
 588        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 589        strbuf_release(&msgbuf);
 590}
 591
 592static struct diff_tempfile *claim_diff_tempfile(void) {
 593        int i;
 594        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 595                if (!diff_temp[i].name)
 596                        return diff_temp + i;
 597        die("BUG: diff is failing to clean up its tempfiles");
 598}
 599
 600static int remove_tempfile_installed;
 601
 602static void remove_tempfile(void)
 603{
 604        int i;
 605        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 606                if (diff_temp[i].name == diff_temp[i].tmp_path)
 607                        unlink_or_warn(diff_temp[i].name);
 608                diff_temp[i].name = NULL;
 609        }
 610}
 611
 612static void remove_tempfile_on_signal(int signo)
 613{
 614        remove_tempfile();
 615        sigchain_pop(signo);
 616        raise(signo);
 617}
 618
 619static void print_line_count(FILE *file, int count)
 620{
 621        switch (count) {
 622        case 0:
 623                fprintf(file, "0,0");
 624                break;
 625        case 1:
 626                fprintf(file, "1");
 627                break;
 628        default:
 629                fprintf(file, "1,%d", count);
 630                break;
 631        }
 632}
 633
 634static void emit_rewrite_lines(struct emit_callback *ecb,
 635                               int prefix, const char *data, int size)
 636{
 637        const char *endp = NULL;
 638        static const char *nneof = " No newline at end of file\n";
 639        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 640
 641        while (0 < size) {
 642                int len;
 643
 644                endp = memchr(data, '\n', size);
 645                len = endp ? (endp - data + 1) : size;
 646                if (prefix != '+') {
 647                        ecb->lno_in_preimage++;
 648                        emit_del_line(reset, ecb, data, len);
 649                } else {
 650                        ecb->lno_in_postimage++;
 651                        emit_add_line(reset, ecb, data, len);
 652                }
 653                size -= len;
 654                data += len;
 655        }
 656        if (!endp) {
 657                const char *context = diff_get_color(ecb->color_diff,
 658                                                     DIFF_CONTEXT);
 659                putc('\n', ecb->opt->file);
 660                emit_line_0(ecb->opt, context, reset, '\\',
 661                            nneof, strlen(nneof));
 662        }
 663}
 664
 665static void emit_rewrite_diff(const char *name_a,
 666                              const char *name_b,
 667                              struct diff_filespec *one,
 668                              struct diff_filespec *two,
 669                              struct userdiff_driver *textconv_one,
 670                              struct userdiff_driver *textconv_two,
 671                              struct diff_options *o)
 672{
 673        int lc_a, lc_b;
 674        const char *name_a_tab, *name_b_tab;
 675        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 676        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 677        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 678        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 679        const char *a_prefix, *b_prefix;
 680        char *data_one, *data_two;
 681        size_t size_one, size_two;
 682        struct emit_callback ecbdata;
 683        const char *line_prefix = diff_line_prefix(o);
 684
 685        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 686                a_prefix = o->b_prefix;
 687                b_prefix = o->a_prefix;
 688        } else {
 689                a_prefix = o->a_prefix;
 690                b_prefix = o->b_prefix;
 691        }
 692
 693        name_a += (*name_a == '/');
 694        name_b += (*name_b == '/');
 695        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 696        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 697
 698        strbuf_reset(&a_name);
 699        strbuf_reset(&b_name);
 700        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 701        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 702
 703        size_one = fill_textconv(textconv_one, one, &data_one);
 704        size_two = fill_textconv(textconv_two, two, &data_two);
 705
 706        memset(&ecbdata, 0, sizeof(ecbdata));
 707        ecbdata.color_diff = want_color(o->use_color);
 708        ecbdata.found_changesp = &o->found_changes;
 709        ecbdata.ws_rule = whitespace_rule(name_b);
 710        ecbdata.opt = o;
 711        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 712                mmfile_t mf1, mf2;
 713                mf1.ptr = (char *)data_one;
 714                mf2.ptr = (char *)data_two;
 715                mf1.size = size_one;
 716                mf2.size = size_two;
 717                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 718        }
 719        ecbdata.lno_in_preimage = 1;
 720        ecbdata.lno_in_postimage = 1;
 721
 722        lc_a = count_lines(data_one, size_one);
 723        lc_b = count_lines(data_two, size_two);
 724        fprintf(o->file,
 725                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 726                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 727                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 728                line_prefix, fraginfo);
 729        if (!o->irreversible_delete)
 730                print_line_count(o->file, lc_a);
 731        else
 732                fprintf(o->file, "?,?");
 733        fprintf(o->file, " +");
 734        print_line_count(o->file, lc_b);
 735        fprintf(o->file, " @@%s\n", reset);
 736        if (lc_a && !o->irreversible_delete)
 737                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 738        if (lc_b)
 739                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 740        if (textconv_one)
 741                free((char *)data_one);
 742        if (textconv_two)
 743                free((char *)data_two);
 744}
 745
 746struct diff_words_buffer {
 747        mmfile_t text;
 748        long alloc;
 749        struct diff_words_orig {
 750                const char *begin, *end;
 751        } *orig;
 752        int orig_nr, orig_alloc;
 753};
 754
 755static void diff_words_append(char *line, unsigned long len,
 756                struct diff_words_buffer *buffer)
 757{
 758        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 759        line++;
 760        len--;
 761        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 762        buffer->text.size += len;
 763        buffer->text.ptr[buffer->text.size] = '\0';
 764}
 765
 766struct diff_words_style_elem {
 767        const char *prefix;
 768        const char *suffix;
 769        const char *color; /* NULL; filled in by the setup code if
 770                            * color is enabled */
 771};
 772
 773struct diff_words_style {
 774        enum diff_words_type type;
 775        struct diff_words_style_elem new, old, ctx;
 776        const char *newline;
 777};
 778
 779static struct diff_words_style diff_words_styles[] = {
 780        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 781        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 782        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 783};
 784
 785struct diff_words_data {
 786        struct diff_words_buffer minus, plus;
 787        const char *current_plus;
 788        int last_minus;
 789        struct diff_options *opt;
 790        regex_t *word_regex;
 791        enum diff_words_type type;
 792        struct diff_words_style *style;
 793};
 794
 795static int fn_out_diff_words_write_helper(FILE *fp,
 796                                          struct diff_words_style_elem *st_el,
 797                                          const char *newline,
 798                                          size_t count, const char *buf,
 799                                          const char *line_prefix)
 800{
 801        int print = 0;
 802
 803        while (count) {
 804                char *p = memchr(buf, '\n', count);
 805                if (print)
 806                        fputs(line_prefix, fp);
 807                if (p != buf) {
 808                        if (st_el->color && fputs(st_el->color, fp) < 0)
 809                                return -1;
 810                        if (fputs(st_el->prefix, fp) < 0 ||
 811                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 812                            fputs(st_el->suffix, fp) < 0)
 813                                return -1;
 814                        if (st_el->color && *st_el->color
 815                            && fputs(GIT_COLOR_RESET, fp) < 0)
 816                                return -1;
 817                }
 818                if (!p)
 819                        return 0;
 820                if (fputs(newline, fp) < 0)
 821                        return -1;
 822                count -= p + 1 - buf;
 823                buf = p + 1;
 824                print = 1;
 825        }
 826        return 0;
 827}
 828
 829/*
 830 * '--color-words' algorithm can be described as:
 831 *
 832 *   1. collect a the minus/plus lines of a diff hunk, divided into
 833 *      minus-lines and plus-lines;
 834 *
 835 *   2. break both minus-lines and plus-lines into words and
 836 *      place them into two mmfile_t with one word for each line;
 837 *
 838 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 839 *
 840 * And for the common parts of the both file, we output the plus side text.
 841 * diff_words->current_plus is used to trace the current position of the plus file
 842 * which printed. diff_words->last_minus is used to trace the last minus word
 843 * printed.
 844 *
 845 * For '--graph' to work with '--color-words', we need to output the graph prefix
 846 * on each line of color words output. Generally, there are two conditions on
 847 * which we should output the prefix.
 848 *
 849 *   1. diff_words->last_minus == 0 &&
 850 *      diff_words->current_plus == diff_words->plus.text.ptr
 851 *
 852 *      that is: the plus text must start as a new line, and if there is no minus
 853 *      word printed, a graph prefix must be printed.
 854 *
 855 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 856 *      *(diff_words->current_plus - 1) == '\n'
 857 *
 858 *      that is: a graph prefix must be printed following a '\n'
 859 */
 860static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 861{
 862        if ((diff_words->last_minus == 0 &&
 863                diff_words->current_plus == diff_words->plus.text.ptr) ||
 864                (diff_words->current_plus > diff_words->plus.text.ptr &&
 865                *(diff_words->current_plus - 1) == '\n')) {
 866                return 1;
 867        } else {
 868                return 0;
 869        }
 870}
 871
 872static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 873{
 874        struct diff_words_data *diff_words = priv;
 875        struct diff_words_style *style = diff_words->style;
 876        int minus_first, minus_len, plus_first, plus_len;
 877        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 878        struct diff_options *opt = diff_words->opt;
 879        const char *line_prefix;
 880
 881        if (line[0] != '@' || parse_hunk_header(line, len,
 882                        &minus_first, &minus_len, &plus_first, &plus_len))
 883                return;
 884
 885        assert(opt);
 886        line_prefix = diff_line_prefix(opt);
 887
 888        /* POSIX requires that first be decremented by one if len == 0... */
 889        if (minus_len) {
 890                minus_begin = diff_words->minus.orig[minus_first].begin;
 891                minus_end =
 892                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 893        } else
 894                minus_begin = minus_end =
 895                        diff_words->minus.orig[minus_first].end;
 896
 897        if (plus_len) {
 898                plus_begin = diff_words->plus.orig[plus_first].begin;
 899                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 900        } else
 901                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 902
 903        if (color_words_output_graph_prefix(diff_words)) {
 904                fputs(line_prefix, diff_words->opt->file);
 905        }
 906        if (diff_words->current_plus != plus_begin) {
 907                fn_out_diff_words_write_helper(diff_words->opt->file,
 908                                &style->ctx, style->newline,
 909                                plus_begin - diff_words->current_plus,
 910                                diff_words->current_plus, line_prefix);
 911                if (*(plus_begin - 1) == '\n')
 912                        fputs(line_prefix, diff_words->opt->file);
 913        }
 914        if (minus_begin != minus_end) {
 915                fn_out_diff_words_write_helper(diff_words->opt->file,
 916                                &style->old, style->newline,
 917                                minus_end - minus_begin, minus_begin,
 918                                line_prefix);
 919        }
 920        if (plus_begin != plus_end) {
 921                fn_out_diff_words_write_helper(diff_words->opt->file,
 922                                &style->new, style->newline,
 923                                plus_end - plus_begin, plus_begin,
 924                                line_prefix);
 925        }
 926
 927        diff_words->current_plus = plus_end;
 928        diff_words->last_minus = minus_first;
 929}
 930
 931/* This function starts looking at *begin, and returns 0 iff a word was found. */
 932static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 933                int *begin, int *end)
 934{
 935        if (word_regex && *begin < buffer->size) {
 936                regmatch_t match[1];
 937                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 938                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 939                                        '\n', match[0].rm_eo - match[0].rm_so);
 940                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 941                        *begin += match[0].rm_so;
 942                        return *begin >= *end;
 943                }
 944                return -1;
 945        }
 946
 947        /* find the next word */
 948        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 949                (*begin)++;
 950        if (*begin >= buffer->size)
 951                return -1;
 952
 953        /* find the end of the word */
 954        *end = *begin + 1;
 955        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 956                (*end)++;
 957
 958        return 0;
 959}
 960
 961/*
 962 * This function splits the words in buffer->text, stores the list with
 963 * newline separator into out, and saves the offsets of the original words
 964 * in buffer->orig.
 965 */
 966static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 967                regex_t *word_regex)
 968{
 969        int i, j;
 970        long alloc = 0;
 971
 972        out->size = 0;
 973        out->ptr = NULL;
 974
 975        /* fake an empty "0th" word */
 976        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 977        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 978        buffer->orig_nr = 1;
 979
 980        for (i = 0; i < buffer->text.size; i++) {
 981                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 982                        return;
 983
 984                /* store original boundaries */
 985                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 986                                buffer->orig_alloc);
 987                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 988                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 989                buffer->orig_nr++;
 990
 991                /* store one word */
 992                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 993                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 994                out->ptr[out->size + j - i] = '\n';
 995                out->size += j - i + 1;
 996
 997                i = j - 1;
 998        }
 999}
1000
1001/* this executes the word diff on the accumulated buffers */
1002static void diff_words_show(struct diff_words_data *diff_words)
1003{
1004        xpparam_t xpp;
1005        xdemitconf_t xecfg;
1006        mmfile_t minus, plus;
1007        struct diff_words_style *style = diff_words->style;
1008
1009        struct diff_options *opt = diff_words->opt;
1010        const char *line_prefix;
1011
1012        assert(opt);
1013        line_prefix = diff_line_prefix(opt);
1014
1015        /* special case: only removal */
1016        if (!diff_words->plus.text.size) {
1017                fputs(line_prefix, diff_words->opt->file);
1018                fn_out_diff_words_write_helper(diff_words->opt->file,
1019                        &style->old, style->newline,
1020                        diff_words->minus.text.size,
1021                        diff_words->minus.text.ptr, line_prefix);
1022                diff_words->minus.text.size = 0;
1023                return;
1024        }
1025
1026        diff_words->current_plus = diff_words->plus.text.ptr;
1027        diff_words->last_minus = 0;
1028
1029        memset(&xpp, 0, sizeof(xpp));
1030        memset(&xecfg, 0, sizeof(xecfg));
1031        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1032        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1033        xpp.flags = 0;
1034        /* as only the hunk header will be parsed, we need a 0-context */
1035        xecfg.ctxlen = 0;
1036        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1037                      &xpp, &xecfg);
1038        free(minus.ptr);
1039        free(plus.ptr);
1040        if (diff_words->current_plus != diff_words->plus.text.ptr +
1041                        diff_words->plus.text.size) {
1042                if (color_words_output_graph_prefix(diff_words))
1043                        fputs(line_prefix, diff_words->opt->file);
1044                fn_out_diff_words_write_helper(diff_words->opt->file,
1045                        &style->ctx, style->newline,
1046                        diff_words->plus.text.ptr + diff_words->plus.text.size
1047                        - diff_words->current_plus, diff_words->current_plus,
1048                        line_prefix);
1049        }
1050        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1051}
1052
1053/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1054static void diff_words_flush(struct emit_callback *ecbdata)
1055{
1056        if (ecbdata->diff_words->minus.text.size ||
1057            ecbdata->diff_words->plus.text.size)
1058                diff_words_show(ecbdata->diff_words);
1059}
1060
1061static void diff_filespec_load_driver(struct diff_filespec *one)
1062{
1063        /* Use already-loaded driver */
1064        if (one->driver)
1065                return;
1066
1067        if (S_ISREG(one->mode))
1068                one->driver = userdiff_find_by_path(one->path);
1069
1070        /* Fallback to default settings */
1071        if (!one->driver)
1072                one->driver = userdiff_find_by_name("default");
1073}
1074
1075static const char *userdiff_word_regex(struct diff_filespec *one)
1076{
1077        diff_filespec_load_driver(one);
1078        return one->driver->word_regex;
1079}
1080
1081static void init_diff_words_data(struct emit_callback *ecbdata,
1082                                 struct diff_options *orig_opts,
1083                                 struct diff_filespec *one,
1084                                 struct diff_filespec *two)
1085{
1086        int i;
1087        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1088        memcpy(o, orig_opts, sizeof(struct diff_options));
1089
1090        ecbdata->diff_words =
1091                xcalloc(1, sizeof(struct diff_words_data));
1092        ecbdata->diff_words->type = o->word_diff;
1093        ecbdata->diff_words->opt = o;
1094        if (!o->word_regex)
1095                o->word_regex = userdiff_word_regex(one);
1096        if (!o->word_regex)
1097                o->word_regex = userdiff_word_regex(two);
1098        if (!o->word_regex)
1099                o->word_regex = diff_word_regex_cfg;
1100        if (o->word_regex) {
1101                ecbdata->diff_words->word_regex = (regex_t *)
1102                        xmalloc(sizeof(regex_t));
1103                if (regcomp(ecbdata->diff_words->word_regex,
1104                            o->word_regex,
1105                            REG_EXTENDED | REG_NEWLINE))
1106                        die ("Invalid regular expression: %s",
1107                             o->word_regex);
1108        }
1109        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1110                if (o->word_diff == diff_words_styles[i].type) {
1111                        ecbdata->diff_words->style =
1112                                &diff_words_styles[i];
1113                        break;
1114                }
1115        }
1116        if (want_color(o->use_color)) {
1117                struct diff_words_style *st = ecbdata->diff_words->style;
1118                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1119                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1120                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1121        }
1122}
1123
1124static void free_diff_words_data(struct emit_callback *ecbdata)
1125{
1126        if (ecbdata->diff_words) {
1127                diff_words_flush(ecbdata);
1128                free (ecbdata->diff_words->opt);
1129                free (ecbdata->diff_words->minus.text.ptr);
1130                free (ecbdata->diff_words->minus.orig);
1131                free (ecbdata->diff_words->plus.text.ptr);
1132                free (ecbdata->diff_words->plus.orig);
1133                if (ecbdata->diff_words->word_regex) {
1134                        regfree(ecbdata->diff_words->word_regex);
1135                        free(ecbdata->diff_words->word_regex);
1136                }
1137                free(ecbdata->diff_words);
1138                ecbdata->diff_words = NULL;
1139        }
1140}
1141
1142const char *diff_get_color(int diff_use_color, enum color_diff ix)
1143{
1144        if (want_color(diff_use_color))
1145                return diff_colors[ix];
1146        return "";
1147}
1148
1149const char *diff_line_prefix(struct diff_options *opt)
1150{
1151        struct strbuf *msgbuf;
1152        if (!opt->output_prefix)
1153                return "";
1154
1155        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1156        return msgbuf->buf;
1157}
1158
1159static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1160{
1161        const char *cp;
1162        unsigned long allot;
1163        size_t l = len;
1164
1165        if (ecb->truncate)
1166                return ecb->truncate(line, len);
1167        cp = line;
1168        allot = l;
1169        while (0 < l) {
1170                (void) utf8_width(&cp, &l);
1171                if (!cp)
1172                        break; /* truncated in the middle? */
1173        }
1174        return allot - l;
1175}
1176
1177static void find_lno(const char *line, struct emit_callback *ecbdata)
1178{
1179        const char *p;
1180        ecbdata->lno_in_preimage = 0;
1181        ecbdata->lno_in_postimage = 0;
1182        p = strchr(line, '-');
1183        if (!p)
1184                return; /* cannot happen */
1185        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1186        p = strchr(p, '+');
1187        if (!p)
1188                return; /* cannot happen */
1189        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1190}
1191
1192static void fn_out_consume(void *priv, char *line, unsigned long len)
1193{
1194        struct emit_callback *ecbdata = priv;
1195        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1196        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1197        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1198        struct diff_options *o = ecbdata->opt;
1199        const char *line_prefix = diff_line_prefix(o);
1200
1201        if (ecbdata->header) {
1202                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1203                strbuf_reset(ecbdata->header);
1204                ecbdata->header = NULL;
1205        }
1206        *(ecbdata->found_changesp) = 1;
1207
1208        if (ecbdata->label_path[0]) {
1209                const char *name_a_tab, *name_b_tab;
1210
1211                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1212                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1213
1214                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1215                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1216                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1217                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1218                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1219        }
1220
1221        if (diff_suppress_blank_empty
1222            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1223                line[0] = '\n';
1224                len = 1;
1225        }
1226
1227        if (line[0] == '@') {
1228                if (ecbdata->diff_words)
1229                        diff_words_flush(ecbdata);
1230                len = sane_truncate_line(ecbdata, line, len);
1231                find_lno(line, ecbdata);
1232                emit_hunk_header(ecbdata, line, len);
1233                if (line[len-1] != '\n')
1234                        putc('\n', ecbdata->opt->file);
1235                return;
1236        }
1237
1238        if (len < 1) {
1239                emit_line(ecbdata->opt, reset, reset, line, len);
1240                if (ecbdata->diff_words
1241                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1242                        fputs("~\n", ecbdata->opt->file);
1243                return;
1244        }
1245
1246        if (ecbdata->diff_words) {
1247                if (line[0] == '-') {
1248                        diff_words_append(line, len,
1249                                          &ecbdata->diff_words->minus);
1250                        return;
1251                } else if (line[0] == '+') {
1252                        diff_words_append(line, len,
1253                                          &ecbdata->diff_words->plus);
1254                        return;
1255                } else if (starts_with(line, "\\ ")) {
1256                        /*
1257                         * Eat the "no newline at eof" marker as if we
1258                         * saw a "+" or "-" line with nothing on it,
1259                         * and return without diff_words_flush() to
1260                         * defer processing. If this is the end of
1261                         * preimage, more "+" lines may come after it.
1262                         */
1263                        return;
1264                }
1265                diff_words_flush(ecbdata);
1266                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1267                        emit_line(ecbdata->opt, context, reset, line, len);
1268                        fputs("~\n", ecbdata->opt->file);
1269                } else {
1270                        /*
1271                         * Skip the prefix character, if any.  With
1272                         * diff_suppress_blank_empty, there may be
1273                         * none.
1274                         */
1275                        if (line[0] != '\n') {
1276                              line++;
1277                              len--;
1278                        }
1279                        emit_line(ecbdata->opt, context, reset, line, len);
1280                }
1281                return;
1282        }
1283
1284        switch (line[0]) {
1285        case '+':
1286                ecbdata->lno_in_postimage++;
1287                emit_add_line(reset, ecbdata, line + 1, len - 1);
1288                break;
1289        case '-':
1290                ecbdata->lno_in_preimage++;
1291                emit_del_line(reset, ecbdata, line + 1, len - 1);
1292                break;
1293        case ' ':
1294                ecbdata->lno_in_postimage++;
1295                ecbdata->lno_in_preimage++;
1296                emit_context_line(reset, ecbdata, line + 1, len - 1);
1297                break;
1298        default:
1299                /* incomplete line at the end */
1300                ecbdata->lno_in_preimage++;
1301                emit_line(ecbdata->opt,
1302                          diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1303                          reset, line, len);
1304                break;
1305        }
1306}
1307
1308static char *pprint_rename(const char *a, const char *b)
1309{
1310        const char *old = a;
1311        const char *new = b;
1312        struct strbuf name = STRBUF_INIT;
1313        int pfx_length, sfx_length;
1314        int pfx_adjust_for_slash;
1315        int len_a = strlen(a);
1316        int len_b = strlen(b);
1317        int a_midlen, b_midlen;
1318        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1319        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1320
1321        if (qlen_a || qlen_b) {
1322                quote_c_style(a, &name, NULL, 0);
1323                strbuf_addstr(&name, " => ");
1324                quote_c_style(b, &name, NULL, 0);
1325                return strbuf_detach(&name, NULL);
1326        }
1327
1328        /* Find common prefix */
1329        pfx_length = 0;
1330        while (*old && *new && *old == *new) {
1331                if (*old == '/')
1332                        pfx_length = old - a + 1;
1333                old++;
1334                new++;
1335        }
1336
1337        /* Find common suffix */
1338        old = a + len_a;
1339        new = b + len_b;
1340        sfx_length = 0;
1341        /*
1342         * If there is a common prefix, it must end in a slash.  In
1343         * that case we let this loop run 1 into the prefix to see the
1344         * same slash.
1345         *
1346         * If there is no common prefix, we cannot do this as it would
1347         * underrun the input strings.
1348         */
1349        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1350        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1351               b + pfx_length - pfx_adjust_for_slash <= new &&
1352               *old == *new) {
1353                if (*old == '/')
1354                        sfx_length = len_a - (old - a);
1355                old--;
1356                new--;
1357        }
1358
1359        /*
1360         * pfx{mid-a => mid-b}sfx
1361         * {pfx-a => pfx-b}sfx
1362         * pfx{sfx-a => sfx-b}
1363         * name-a => name-b
1364         */
1365        a_midlen = len_a - pfx_length - sfx_length;
1366        b_midlen = len_b - pfx_length - sfx_length;
1367        if (a_midlen < 0)
1368                a_midlen = 0;
1369        if (b_midlen < 0)
1370                b_midlen = 0;
1371
1372        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1373        if (pfx_length + sfx_length) {
1374                strbuf_add(&name, a, pfx_length);
1375                strbuf_addch(&name, '{');
1376        }
1377        strbuf_add(&name, a + pfx_length, a_midlen);
1378        strbuf_addstr(&name, " => ");
1379        strbuf_add(&name, b + pfx_length, b_midlen);
1380        if (pfx_length + sfx_length) {
1381                strbuf_addch(&name, '}');
1382                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1383        }
1384        return strbuf_detach(&name, NULL);
1385}
1386
1387struct diffstat_t {
1388        int nr;
1389        int alloc;
1390        struct diffstat_file {
1391                char *from_name;
1392                char *name;
1393                char *print_name;
1394                unsigned is_unmerged:1;
1395                unsigned is_binary:1;
1396                unsigned is_renamed:1;
1397                unsigned is_interesting:1;
1398                uintmax_t added, deleted;
1399        } **files;
1400};
1401
1402static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1403                                          const char *name_a,
1404                                          const char *name_b)
1405{
1406        struct diffstat_file *x;
1407        x = xcalloc(1, sizeof(*x));
1408        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1409        diffstat->files[diffstat->nr++] = x;
1410        if (name_b) {
1411                x->from_name = xstrdup(name_a);
1412                x->name = xstrdup(name_b);
1413                x->is_renamed = 1;
1414        }
1415        else {
1416                x->from_name = NULL;
1417                x->name = xstrdup(name_a);
1418        }
1419        return x;
1420}
1421
1422static void diffstat_consume(void *priv, char *line, unsigned long len)
1423{
1424        struct diffstat_t *diffstat = priv;
1425        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1426
1427        if (line[0] == '+')
1428                x->added++;
1429        else if (line[0] == '-')
1430                x->deleted++;
1431}
1432
1433const char mime_boundary_leader[] = "------------";
1434
1435static int scale_linear(int it, int width, int max_change)
1436{
1437        if (!it)
1438                return 0;
1439        /*
1440         * make sure that at least one '-' or '+' is printed if
1441         * there is any change to this path. The easiest way is to
1442         * scale linearly as if the alloted width is one column shorter
1443         * than it is, and then add 1 to the result.
1444         */
1445        return 1 + (it * (width - 1) / max_change);
1446}
1447
1448static void show_name(FILE *file,
1449                      const char *prefix, const char *name, int len)
1450{
1451        fprintf(file, " %s%-*s |", prefix, len, name);
1452}
1453
1454static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1455{
1456        if (cnt <= 0)
1457                return;
1458        fprintf(file, "%s", set);
1459        while (cnt--)
1460                putc(ch, file);
1461        fprintf(file, "%s", reset);
1462}
1463
1464static void fill_print_name(struct diffstat_file *file)
1465{
1466        char *pname;
1467
1468        if (file->print_name)
1469                return;
1470
1471        if (!file->is_renamed) {
1472                struct strbuf buf = STRBUF_INIT;
1473                if (quote_c_style(file->name, &buf, NULL, 0)) {
1474                        pname = strbuf_detach(&buf, NULL);
1475                } else {
1476                        pname = file->name;
1477                        strbuf_release(&buf);
1478                }
1479        } else {
1480                pname = pprint_rename(file->from_name, file->name);
1481        }
1482        file->print_name = pname;
1483}
1484
1485int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1486{
1487        struct strbuf sb = STRBUF_INIT;
1488        int ret;
1489
1490        if (!files) {
1491                assert(insertions == 0 && deletions == 0);
1492                return fprintf(fp, "%s\n", " 0 files changed");
1493        }
1494
1495        strbuf_addf(&sb,
1496                    (files == 1) ? " %d file changed" : " %d files changed",
1497                    files);
1498
1499        /*
1500         * For binary diff, the caller may want to print "x files
1501         * changed" with insertions == 0 && deletions == 0.
1502         *
1503         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1504         * is probably less confusing (i.e skip over "2 files changed
1505         * but nothing about added/removed lines? Is this a bug in Git?").
1506         */
1507        if (insertions || deletions == 0) {
1508                strbuf_addf(&sb,
1509                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1510                            insertions);
1511        }
1512
1513        if (deletions || insertions == 0) {
1514                strbuf_addf(&sb,
1515                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1516                            deletions);
1517        }
1518        strbuf_addch(&sb, '\n');
1519        ret = fputs(sb.buf, fp);
1520        strbuf_release(&sb);
1521        return ret;
1522}
1523
1524static void show_stats(struct diffstat_t *data, struct diff_options *options)
1525{
1526        int i, len, add, del, adds = 0, dels = 0;
1527        uintmax_t max_change = 0, max_len = 0;
1528        int total_files = data->nr, count;
1529        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1530        const char *reset, *add_c, *del_c;
1531        const char *line_prefix = "";
1532        int extra_shown = 0;
1533
1534        if (data->nr == 0)
1535                return;
1536
1537        line_prefix = diff_line_prefix(options);
1538        count = options->stat_count ? options->stat_count : data->nr;
1539
1540        reset = diff_get_color_opt(options, DIFF_RESET);
1541        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1542        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1543
1544        /*
1545         * Find the longest filename and max number of changes
1546         */
1547        for (i = 0; (i < count) && (i < data->nr); i++) {
1548                struct diffstat_file *file = data->files[i];
1549                uintmax_t change = file->added + file->deleted;
1550
1551                if (!file->is_interesting && (change == 0)) {
1552                        count++; /* not shown == room for one more */
1553                        continue;
1554                }
1555                fill_print_name(file);
1556                len = strlen(file->print_name);
1557                if (max_len < len)
1558                        max_len = len;
1559
1560                if (file->is_unmerged) {
1561                        /* "Unmerged" is 8 characters */
1562                        bin_width = bin_width < 8 ? 8 : bin_width;
1563                        continue;
1564                }
1565                if (file->is_binary) {
1566                        /* "Bin XXX -> YYY bytes" */
1567                        int w = 14 + decimal_width(file->added)
1568                                + decimal_width(file->deleted);
1569                        bin_width = bin_width < w ? w : bin_width;
1570                        /* Display change counts aligned with "Bin" */
1571                        number_width = 3;
1572                        continue;
1573                }
1574
1575                if (max_change < change)
1576                        max_change = change;
1577        }
1578        count = i; /* where we can stop scanning in data->files[] */
1579
1580        /*
1581         * We have width = stat_width or term_columns() columns total.
1582         * We want a maximum of min(max_len, stat_name_width) for the name part.
1583         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1584         * We also need 1 for " " and 4 + decimal_width(max_change)
1585         * for " | NNNN " and one the empty column at the end, altogether
1586         * 6 + decimal_width(max_change).
1587         *
1588         * If there's not enough space, we will use the smaller of
1589         * stat_name_width (if set) and 5/8*width for the filename,
1590         * and the rest for constant elements + graph part, but no more
1591         * than stat_graph_width for the graph part.
1592         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1593         * for the standard terminal size).
1594         *
1595         * In other words: stat_width limits the maximum width, and
1596         * stat_name_width fixes the maximum width of the filename,
1597         * and is also used to divide available columns if there
1598         * aren't enough.
1599         *
1600         * Binary files are displayed with "Bin XXX -> YYY bytes"
1601         * instead of the change count and graph. This part is treated
1602         * similarly to the graph part, except that it is not
1603         * "scaled". If total width is too small to accommodate the
1604         * guaranteed minimum width of the filename part and the
1605         * separators and this message, this message will "overflow"
1606         * making the line longer than the maximum width.
1607         */
1608
1609        if (options->stat_width == -1)
1610                width = term_columns() - options->output_prefix_length;
1611        else
1612                width = options->stat_width ? options->stat_width : 80;
1613        number_width = decimal_width(max_change) > number_width ?
1614                decimal_width(max_change) : number_width;
1615
1616        if (options->stat_graph_width == -1)
1617                options->stat_graph_width = diff_stat_graph_width;
1618
1619        /*
1620         * Guarantee 3/8*16==6 for the graph part
1621         * and 5/8*16==10 for the filename part
1622         */
1623        if (width < 16 + 6 + number_width)
1624                width = 16 + 6 + number_width;
1625
1626        /*
1627         * First assign sizes that are wanted, ignoring available width.
1628         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1629         * starting from "XXX" should fit in graph_width.
1630         */
1631        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1632        if (options->stat_graph_width &&
1633            options->stat_graph_width < graph_width)
1634                graph_width = options->stat_graph_width;
1635
1636        name_width = (options->stat_name_width > 0 &&
1637                      options->stat_name_width < max_len) ?
1638                options->stat_name_width : max_len;
1639
1640        /*
1641         * Adjust adjustable widths not to exceed maximum width
1642         */
1643        if (name_width + number_width + 6 + graph_width > width) {
1644                if (graph_width > width * 3/8 - number_width - 6) {
1645                        graph_width = width * 3/8 - number_width - 6;
1646                        if (graph_width < 6)
1647                                graph_width = 6;
1648                }
1649
1650                if (options->stat_graph_width &&
1651                    graph_width > options->stat_graph_width)
1652                        graph_width = options->stat_graph_width;
1653                if (name_width > width - number_width - 6 - graph_width)
1654                        name_width = width - number_width - 6 - graph_width;
1655                else
1656                        graph_width = width - number_width - 6 - name_width;
1657        }
1658
1659        /*
1660         * From here name_width is the width of the name area,
1661         * and graph_width is the width of the graph area.
1662         * max_change is used to scale graph properly.
1663         */
1664        for (i = 0; i < count; i++) {
1665                const char *prefix = "";
1666                struct diffstat_file *file = data->files[i];
1667                char *name = file->print_name;
1668                uintmax_t added = file->added;
1669                uintmax_t deleted = file->deleted;
1670                int name_len;
1671
1672                if (!file->is_interesting && (added + deleted == 0))
1673                        continue;
1674
1675                /*
1676                 * "scale" the filename
1677                 */
1678                len = name_width;
1679                name_len = strlen(name);
1680                if (name_width < name_len) {
1681                        char *slash;
1682                        prefix = "...";
1683                        len -= 3;
1684                        name += name_len - len;
1685                        slash = strchr(name, '/');
1686                        if (slash)
1687                                name = slash;
1688                }
1689
1690                if (file->is_binary) {
1691                        fprintf(options->file, "%s", line_prefix);
1692                        show_name(options->file, prefix, name, len);
1693                        fprintf(options->file, " %*s", number_width, "Bin");
1694                        if (!added && !deleted) {
1695                                putc('\n', options->file);
1696                                continue;
1697                        }
1698                        fprintf(options->file, " %s%"PRIuMAX"%s",
1699                                del_c, deleted, reset);
1700                        fprintf(options->file, " -> ");
1701                        fprintf(options->file, "%s%"PRIuMAX"%s",
1702                                add_c, added, reset);
1703                        fprintf(options->file, " bytes");
1704                        fprintf(options->file, "\n");
1705                        continue;
1706                }
1707                else if (file->is_unmerged) {
1708                        fprintf(options->file, "%s", line_prefix);
1709                        show_name(options->file, prefix, name, len);
1710                        fprintf(options->file, " Unmerged\n");
1711                        continue;
1712                }
1713
1714                /*
1715                 * scale the add/delete
1716                 */
1717                add = added;
1718                del = deleted;
1719
1720                if (graph_width <= max_change) {
1721                        int total = scale_linear(add + del, graph_width, max_change);
1722                        if (total < 2 && add && del)
1723                                /* width >= 2 due to the sanity check */
1724                                total = 2;
1725                        if (add < del) {
1726                                add = scale_linear(add, graph_width, max_change);
1727                                del = total - add;
1728                        } else {
1729                                del = scale_linear(del, graph_width, max_change);
1730                                add = total - del;
1731                        }
1732                }
1733                fprintf(options->file, "%s", line_prefix);
1734                show_name(options->file, prefix, name, len);
1735                fprintf(options->file, " %*"PRIuMAX"%s",
1736                        number_width, added + deleted,
1737                        added + deleted ? " " : "");
1738                show_graph(options->file, '+', add, add_c, reset);
1739                show_graph(options->file, '-', del, del_c, reset);
1740                fprintf(options->file, "\n");
1741        }
1742
1743        for (i = 0; i < data->nr; i++) {
1744                struct diffstat_file *file = data->files[i];
1745                uintmax_t added = file->added;
1746                uintmax_t deleted = file->deleted;
1747
1748                if (file->is_unmerged ||
1749                    (!file->is_interesting && (added + deleted == 0))) {
1750                        total_files--;
1751                        continue;
1752                }
1753
1754                if (!file->is_binary) {
1755                        adds += added;
1756                        dels += deleted;
1757                }
1758                if (i < count)
1759                        continue;
1760                if (!extra_shown)
1761                        fprintf(options->file, "%s ...\n", line_prefix);
1762                extra_shown = 1;
1763        }
1764        fprintf(options->file, "%s", line_prefix);
1765        print_stat_summary(options->file, total_files, adds, dels);
1766}
1767
1768static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1769{
1770        int i, adds = 0, dels = 0, total_files = data->nr;
1771
1772        if (data->nr == 0)
1773                return;
1774
1775        for (i = 0; i < data->nr; i++) {
1776                int added = data->files[i]->added;
1777                int deleted= data->files[i]->deleted;
1778
1779                if (data->files[i]->is_unmerged ||
1780                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1781                        total_files--;
1782                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1783                        adds += added;
1784                        dels += deleted;
1785                }
1786        }
1787        fprintf(options->file, "%s", diff_line_prefix(options));
1788        print_stat_summary(options->file, total_files, adds, dels);
1789}
1790
1791static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1792{
1793        int i;
1794
1795        if (data->nr == 0)
1796                return;
1797
1798        for (i = 0; i < data->nr; i++) {
1799                struct diffstat_file *file = data->files[i];
1800
1801                fprintf(options->file, "%s", diff_line_prefix(options));
1802
1803                if (file->is_binary)
1804                        fprintf(options->file, "-\t-\t");
1805                else
1806                        fprintf(options->file,
1807                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1808                                file->added, file->deleted);
1809                if (options->line_termination) {
1810                        fill_print_name(file);
1811                        if (!file->is_renamed)
1812                                write_name_quoted(file->name, options->file,
1813                                                  options->line_termination);
1814                        else {
1815                                fputs(file->print_name, options->file);
1816                                putc(options->line_termination, options->file);
1817                        }
1818                } else {
1819                        if (file->is_renamed) {
1820                                putc('\0', options->file);
1821                                write_name_quoted(file->from_name, options->file, '\0');
1822                        }
1823                        write_name_quoted(file->name, options->file, '\0');
1824                }
1825        }
1826}
1827
1828struct dirstat_file {
1829        const char *name;
1830        unsigned long changed;
1831};
1832
1833struct dirstat_dir {
1834        struct dirstat_file *files;
1835        int alloc, nr, permille, cumulative;
1836};
1837
1838static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1839                unsigned long changed, const char *base, int baselen)
1840{
1841        unsigned long this_dir = 0;
1842        unsigned int sources = 0;
1843        const char *line_prefix = diff_line_prefix(opt);
1844
1845        while (dir->nr) {
1846                struct dirstat_file *f = dir->files;
1847                int namelen = strlen(f->name);
1848                unsigned long this;
1849                char *slash;
1850
1851                if (namelen < baselen)
1852                        break;
1853                if (memcmp(f->name, base, baselen))
1854                        break;
1855                slash = strchr(f->name + baselen, '/');
1856                if (slash) {
1857                        int newbaselen = slash + 1 - f->name;
1858                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1859                        sources++;
1860                } else {
1861                        this = f->changed;
1862                        dir->files++;
1863                        dir->nr--;
1864                        sources += 2;
1865                }
1866                this_dir += this;
1867        }
1868
1869        /*
1870         * We don't report dirstat's for
1871         *  - the top level
1872         *  - or cases where everything came from a single directory
1873         *    under this directory (sources == 1).
1874         */
1875        if (baselen && sources != 1) {
1876                if (this_dir) {
1877                        int permille = this_dir * 1000 / changed;
1878                        if (permille >= dir->permille) {
1879                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1880                                        permille / 10, permille % 10, baselen, base);
1881                                if (!dir->cumulative)
1882                                        return 0;
1883                        }
1884                }
1885        }
1886        return this_dir;
1887}
1888
1889static int dirstat_compare(const void *_a, const void *_b)
1890{
1891        const struct dirstat_file *a = _a;
1892        const struct dirstat_file *b = _b;
1893        return strcmp(a->name, b->name);
1894}
1895
1896static void show_dirstat(struct diff_options *options)
1897{
1898        int i;
1899        unsigned long changed;
1900        struct dirstat_dir dir;
1901        struct diff_queue_struct *q = &diff_queued_diff;
1902
1903        dir.files = NULL;
1904        dir.alloc = 0;
1905        dir.nr = 0;
1906        dir.permille = options->dirstat_permille;
1907        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1908
1909        changed = 0;
1910        for (i = 0; i < q->nr; i++) {
1911                struct diff_filepair *p = q->queue[i];
1912                const char *name;
1913                unsigned long copied, added, damage;
1914                int content_changed;
1915
1916                name = p->two->path ? p->two->path : p->one->path;
1917
1918                if (p->one->sha1_valid && p->two->sha1_valid)
1919                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1920                else
1921                        content_changed = 1;
1922
1923                if (!content_changed) {
1924                        /*
1925                         * The SHA1 has not changed, so pre-/post-content is
1926                         * identical. We can therefore skip looking at the
1927                         * file contents altogether.
1928                         */
1929                        damage = 0;
1930                        goto found_damage;
1931                }
1932
1933                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1934                        /*
1935                         * In --dirstat-by-file mode, we don't really need to
1936                         * look at the actual file contents at all.
1937                         * The fact that the SHA1 changed is enough for us to
1938                         * add this file to the list of results
1939                         * (with each file contributing equal damage).
1940                         */
1941                        damage = 1;
1942                        goto found_damage;
1943                }
1944
1945                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1946                        diff_populate_filespec(p->one, 0);
1947                        diff_populate_filespec(p->two, 0);
1948                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1949                                               &copied, &added);
1950                        diff_free_filespec_data(p->one);
1951                        diff_free_filespec_data(p->two);
1952                } else if (DIFF_FILE_VALID(p->one)) {
1953                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1954                        copied = added = 0;
1955                        diff_free_filespec_data(p->one);
1956                } else if (DIFF_FILE_VALID(p->two)) {
1957                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1958                        copied = 0;
1959                        added = p->two->size;
1960                        diff_free_filespec_data(p->two);
1961                } else
1962                        continue;
1963
1964                /*
1965                 * Original minus copied is the removed material,
1966                 * added is the new material.  They are both damages
1967                 * made to the preimage.
1968                 * If the resulting damage is zero, we know that
1969                 * diffcore_count_changes() considers the two entries to
1970                 * be identical, but since content_changed is true, we
1971                 * know that there must have been _some_ kind of change,
1972                 * so we force all entries to have damage > 0.
1973                 */
1974                damage = (p->one->size - copied) + added;
1975                if (!damage)
1976                        damage = 1;
1977
1978found_damage:
1979                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1980                dir.files[dir.nr].name = name;
1981                dir.files[dir.nr].changed = damage;
1982                changed += damage;
1983                dir.nr++;
1984        }
1985
1986        /* This can happen even with many files, if everything was renames */
1987        if (!changed)
1988                return;
1989
1990        /* Show all directories with more than x% of the changes */
1991        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1992        gather_dirstat(options, &dir, changed, "", 0);
1993}
1994
1995static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1996{
1997        int i;
1998        unsigned long changed;
1999        struct dirstat_dir dir;
2000
2001        if (data->nr == 0)
2002                return;
2003
2004        dir.files = NULL;
2005        dir.alloc = 0;
2006        dir.nr = 0;
2007        dir.permille = options->dirstat_permille;
2008        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2009
2010        changed = 0;
2011        for (i = 0; i < data->nr; i++) {
2012                struct diffstat_file *file = data->files[i];
2013                unsigned long damage = file->added + file->deleted;
2014                if (file->is_binary)
2015                        /*
2016                         * binary files counts bytes, not lines. Must find some
2017                         * way to normalize binary bytes vs. textual lines.
2018                         * The following heuristic assumes that there are 64
2019                         * bytes per "line".
2020                         * This is stupid and ugly, but very cheap...
2021                         */
2022                        damage = (damage + 63) / 64;
2023                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2024                dir.files[dir.nr].name = file->name;
2025                dir.files[dir.nr].changed = damage;
2026                changed += damage;
2027                dir.nr++;
2028        }
2029
2030        /* This can happen even with many files, if everything was renames */
2031        if (!changed)
2032                return;
2033
2034        /* Show all directories with more than x% of the changes */
2035        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2036        gather_dirstat(options, &dir, changed, "", 0);
2037}
2038
2039static void free_diffstat_info(struct diffstat_t *diffstat)
2040{
2041        int i;
2042        for (i = 0; i < diffstat->nr; i++) {
2043                struct diffstat_file *f = diffstat->files[i];
2044                if (f->name != f->print_name)
2045                        free(f->print_name);
2046                free(f->name);
2047                free(f->from_name);
2048                free(f);
2049        }
2050        free(diffstat->files);
2051}
2052
2053struct checkdiff_t {
2054        const char *filename;
2055        int lineno;
2056        int conflict_marker_size;
2057        struct diff_options *o;
2058        unsigned ws_rule;
2059        unsigned status;
2060};
2061
2062static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2063{
2064        char firstchar;
2065        int cnt;
2066
2067        if (len < marker_size + 1)
2068                return 0;
2069        firstchar = line[0];
2070        switch (firstchar) {
2071        case '=': case '>': case '<': case '|':
2072                break;
2073        default:
2074                return 0;
2075        }
2076        for (cnt = 1; cnt < marker_size; cnt++)
2077                if (line[cnt] != firstchar)
2078                        return 0;
2079        /* line[1] thru line[marker_size-1] are same as firstchar */
2080        if (len < marker_size + 1 || !isspace(line[marker_size]))
2081                return 0;
2082        return 1;
2083}
2084
2085static void checkdiff_consume(void *priv, char *line, unsigned long len)
2086{
2087        struct checkdiff_t *data = priv;
2088        int marker_size = data->conflict_marker_size;
2089        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2090        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2091        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2092        char *err;
2093        const char *line_prefix;
2094
2095        assert(data->o);
2096        line_prefix = diff_line_prefix(data->o);
2097
2098        if (line[0] == '+') {
2099                unsigned bad;
2100                data->lineno++;
2101                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2102                        data->status |= 1;
2103                        fprintf(data->o->file,
2104                                "%s%s:%d: leftover conflict marker\n",
2105                                line_prefix, data->filename, data->lineno);
2106                }
2107                bad = ws_check(line + 1, len - 1, data->ws_rule);
2108                if (!bad)
2109                        return;
2110                data->status |= bad;
2111                err = whitespace_error_string(bad);
2112                fprintf(data->o->file, "%s%s:%d: %s.\n",
2113                        line_prefix, data->filename, data->lineno, err);
2114                free(err);
2115                emit_line(data->o, set, reset, line, 1);
2116                ws_check_emit(line + 1, len - 1, data->ws_rule,
2117                              data->o->file, set, reset, ws);
2118        } else if (line[0] == ' ') {
2119                data->lineno++;
2120        } else if (line[0] == '@') {
2121                char *plus = strchr(line, '+');
2122                if (plus)
2123                        data->lineno = strtol(plus, NULL, 10) - 1;
2124                else
2125                        die("invalid diff");
2126        }
2127}
2128
2129static unsigned char *deflate_it(char *data,
2130                                 unsigned long size,
2131                                 unsigned long *result_size)
2132{
2133        int bound;
2134        unsigned char *deflated;
2135        git_zstream stream;
2136
2137        git_deflate_init(&stream, zlib_compression_level);
2138        bound = git_deflate_bound(&stream, size);
2139        deflated = xmalloc(bound);
2140        stream.next_out = deflated;
2141        stream.avail_out = bound;
2142
2143        stream.next_in = (unsigned char *)data;
2144        stream.avail_in = size;
2145        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2146                ; /* nothing */
2147        git_deflate_end(&stream);
2148        *result_size = stream.total_out;
2149        return deflated;
2150}
2151
2152static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2153                                  const char *prefix)
2154{
2155        void *cp;
2156        void *delta;
2157        void *deflated;
2158        void *data;
2159        unsigned long orig_size;
2160        unsigned long delta_size;
2161        unsigned long deflate_size;
2162        unsigned long data_size;
2163
2164        /* We could do deflated delta, or we could do just deflated two,
2165         * whichever is smaller.
2166         */
2167        delta = NULL;
2168        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2169        if (one->size && two->size) {
2170                delta = diff_delta(one->ptr, one->size,
2171                                   two->ptr, two->size,
2172                                   &delta_size, deflate_size);
2173                if (delta) {
2174                        void *to_free = delta;
2175                        orig_size = delta_size;
2176                        delta = deflate_it(delta, delta_size, &delta_size);
2177                        free(to_free);
2178                }
2179        }
2180
2181        if (delta && delta_size < deflate_size) {
2182                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2183                free(deflated);
2184                data = delta;
2185                data_size = delta_size;
2186        }
2187        else {
2188                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2189                free(delta);
2190                data = deflated;
2191                data_size = deflate_size;
2192        }
2193
2194        /* emit data encoded in base85 */
2195        cp = data;
2196        while (data_size) {
2197                int bytes = (52 < data_size) ? 52 : data_size;
2198                char line[70];
2199                data_size -= bytes;
2200                if (bytes <= 26)
2201                        line[0] = bytes + 'A' - 1;
2202                else
2203                        line[0] = bytes - 26 + 'a' - 1;
2204                encode_85(line + 1, cp, bytes);
2205                cp = (char *) cp + bytes;
2206                fprintf(file, "%s", prefix);
2207                fputs(line, file);
2208                fputc('\n', file);
2209        }
2210        fprintf(file, "%s\n", prefix);
2211        free(data);
2212}
2213
2214static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2215                             const char *prefix)
2216{
2217        fprintf(file, "%sGIT binary patch\n", prefix);
2218        emit_binary_diff_body(file, one, two, prefix);
2219        emit_binary_diff_body(file, two, one, prefix);
2220}
2221
2222int diff_filespec_is_binary(struct diff_filespec *one)
2223{
2224        if (one->is_binary == -1) {
2225                diff_filespec_load_driver(one);
2226                if (one->driver->binary != -1)
2227                        one->is_binary = one->driver->binary;
2228                else {
2229                        if (!one->data && DIFF_FILE_VALID(one))
2230                                diff_populate_filespec(one, CHECK_BINARY);
2231                        if (one->is_binary == -1 && one->data)
2232                                one->is_binary = buffer_is_binary(one->data,
2233                                                one->size);
2234                        if (one->is_binary == -1)
2235                                one->is_binary = 0;
2236                }
2237        }
2238        return one->is_binary;
2239}
2240
2241static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2242{
2243        diff_filespec_load_driver(one);
2244        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2245}
2246
2247void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2248{
2249        if (!options->a_prefix)
2250                options->a_prefix = a;
2251        if (!options->b_prefix)
2252                options->b_prefix = b;
2253}
2254
2255struct userdiff_driver *get_textconv(struct diff_filespec *one)
2256{
2257        if (!DIFF_FILE_VALID(one))
2258                return NULL;
2259
2260        diff_filespec_load_driver(one);
2261        return userdiff_get_textconv(one->driver);
2262}
2263
2264static void builtin_diff(const char *name_a,
2265                         const char *name_b,
2266                         struct diff_filespec *one,
2267                         struct diff_filespec *two,
2268                         const char *xfrm_msg,
2269                         int must_show_header,
2270                         struct diff_options *o,
2271                         int complete_rewrite)
2272{
2273        mmfile_t mf1, mf2;
2274        const char *lbl[2];
2275        char *a_one, *b_two;
2276        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2277        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2278        const char *a_prefix, *b_prefix;
2279        struct userdiff_driver *textconv_one = NULL;
2280        struct userdiff_driver *textconv_two = NULL;
2281        struct strbuf header = STRBUF_INIT;
2282        const char *line_prefix = diff_line_prefix(o);
2283
2284        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2285                        (!one->mode || S_ISGITLINK(one->mode)) &&
2286                        (!two->mode || S_ISGITLINK(two->mode))) {
2287                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2288                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2289                show_submodule_summary(o->file, one->path ? one->path : two->path,
2290                                line_prefix,
2291                                one->sha1, two->sha1, two->dirty_submodule,
2292                                meta, del, add, reset);
2293                return;
2294        }
2295
2296        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2297                textconv_one = get_textconv(one);
2298                textconv_two = get_textconv(two);
2299        }
2300
2301        diff_set_mnemonic_prefix(o, "a/", "b/");
2302        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2303                a_prefix = o->b_prefix;
2304                b_prefix = o->a_prefix;
2305        } else {
2306                a_prefix = o->a_prefix;
2307                b_prefix = o->b_prefix;
2308        }
2309
2310        /* Never use a non-valid filename anywhere if at all possible */
2311        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2312        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2313
2314        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2315        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2316        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2317        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2318        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2319        if (lbl[0][0] == '/') {
2320                /* /dev/null */
2321                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2322                if (xfrm_msg)
2323                        strbuf_addstr(&header, xfrm_msg);
2324                must_show_header = 1;
2325        }
2326        else if (lbl[1][0] == '/') {
2327                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2328                if (xfrm_msg)
2329                        strbuf_addstr(&header, xfrm_msg);
2330                must_show_header = 1;
2331        }
2332        else {
2333                if (one->mode != two->mode) {
2334                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2335                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2336                        must_show_header = 1;
2337                }
2338                if (xfrm_msg)
2339                        strbuf_addstr(&header, xfrm_msg);
2340
2341                /*
2342                 * we do not run diff between different kind
2343                 * of objects.
2344                 */
2345                if ((one->mode ^ two->mode) & S_IFMT)
2346                        goto free_ab_and_return;
2347                if (complete_rewrite &&
2348                    (textconv_one || !diff_filespec_is_binary(one)) &&
2349                    (textconv_two || !diff_filespec_is_binary(two))) {
2350                        fprintf(o->file, "%s", header.buf);
2351                        strbuf_reset(&header);
2352                        emit_rewrite_diff(name_a, name_b, one, two,
2353                                                textconv_one, textconv_two, o);
2354                        o->found_changes = 1;
2355                        goto free_ab_and_return;
2356                }
2357        }
2358
2359        if (o->irreversible_delete && lbl[1][0] == '/') {
2360                fprintf(o->file, "%s", header.buf);
2361                strbuf_reset(&header);
2362                goto free_ab_and_return;
2363        } else if (!DIFF_OPT_TST(o, TEXT) &&
2364            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2365              (!textconv_two && diff_filespec_is_binary(two)) )) {
2366                if (!one->data && !two->data &&
2367                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2368                    !DIFF_OPT_TST(o, BINARY)) {
2369                        if (!hashcmp(one->sha1, two->sha1)) {
2370                                if (must_show_header)
2371                                        fprintf(o->file, "%s", header.buf);
2372                                goto free_ab_and_return;
2373                        }
2374                        fprintf(o->file, "%s", header.buf);
2375                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2376                                line_prefix, lbl[0], lbl[1]);
2377                        goto free_ab_and_return;
2378                }
2379                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2380                        die("unable to read files to diff");
2381                /* Quite common confusing case */
2382                if (mf1.size == mf2.size &&
2383                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2384                        if (must_show_header)
2385                                fprintf(o->file, "%s", header.buf);
2386                        goto free_ab_and_return;
2387                }
2388                fprintf(o->file, "%s", header.buf);
2389                strbuf_reset(&header);
2390                if (DIFF_OPT_TST(o, BINARY))
2391                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2392                else
2393                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2394                                line_prefix, lbl[0], lbl[1]);
2395                o->found_changes = 1;
2396        } else {
2397                /* Crazy xdl interfaces.. */
2398                const char *diffopts = getenv("GIT_DIFF_OPTS");
2399                const char *v;
2400                xpparam_t xpp;
2401                xdemitconf_t xecfg;
2402                struct emit_callback ecbdata;
2403                const struct userdiff_funcname *pe;
2404
2405                if (must_show_header) {
2406                        fprintf(o->file, "%s", header.buf);
2407                        strbuf_reset(&header);
2408                }
2409
2410                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2411                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2412
2413                pe = diff_funcname_pattern(one);
2414                if (!pe)
2415                        pe = diff_funcname_pattern(two);
2416
2417                memset(&xpp, 0, sizeof(xpp));
2418                memset(&xecfg, 0, sizeof(xecfg));
2419                memset(&ecbdata, 0, sizeof(ecbdata));
2420                ecbdata.label_path = lbl;
2421                ecbdata.color_diff = want_color(o->use_color);
2422                ecbdata.found_changesp = &o->found_changes;
2423                ecbdata.ws_rule = whitespace_rule(name_b);
2424                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2425                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2426                ecbdata.opt = o;
2427                ecbdata.header = header.len ? &header : NULL;
2428                xpp.flags = o->xdl_opts;
2429                xecfg.ctxlen = o->context;
2430                xecfg.interhunkctxlen = o->interhunkcontext;
2431                xecfg.flags = XDL_EMIT_FUNCNAMES;
2432                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2433                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2434                if (pe)
2435                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2436                if (!diffopts)
2437                        ;
2438                else if (skip_prefix(diffopts, "--unified=", &v))
2439                        xecfg.ctxlen = strtoul(v, NULL, 10);
2440                else if (skip_prefix(diffopts, "-u", &v))
2441                        xecfg.ctxlen = strtoul(v, NULL, 10);
2442                if (o->word_diff)
2443                        init_diff_words_data(&ecbdata, o, one, two);
2444                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2445                              &xpp, &xecfg);
2446                if (o->word_diff)
2447                        free_diff_words_data(&ecbdata);
2448                if (textconv_one)
2449                        free(mf1.ptr);
2450                if (textconv_two)
2451                        free(mf2.ptr);
2452                xdiff_clear_find_func(&xecfg);
2453        }
2454
2455 free_ab_and_return:
2456        strbuf_release(&header);
2457        diff_free_filespec_data(one);
2458        diff_free_filespec_data(two);
2459        free(a_one);
2460        free(b_two);
2461        return;
2462}
2463
2464static void builtin_diffstat(const char *name_a, const char *name_b,
2465                             struct diff_filespec *one,
2466                             struct diff_filespec *two,
2467                             struct diffstat_t *diffstat,
2468                             struct diff_options *o,
2469                             struct diff_filepair *p)
2470{
2471        mmfile_t mf1, mf2;
2472        struct diffstat_file *data;
2473        int same_contents;
2474        int complete_rewrite = 0;
2475
2476        if (!DIFF_PAIR_UNMERGED(p)) {
2477                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2478                        complete_rewrite = 1;
2479        }
2480
2481        data = diffstat_add(diffstat, name_a, name_b);
2482        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2483
2484        if (!one || !two) {
2485                data->is_unmerged = 1;
2486                return;
2487        }
2488
2489        same_contents = !hashcmp(one->sha1, two->sha1);
2490
2491        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2492                data->is_binary = 1;
2493                if (same_contents) {
2494                        data->added = 0;
2495                        data->deleted = 0;
2496                } else {
2497                        data->added = diff_filespec_size(two);
2498                        data->deleted = diff_filespec_size(one);
2499                }
2500        }
2501
2502        else if (complete_rewrite) {
2503                diff_populate_filespec(one, 0);
2504                diff_populate_filespec(two, 0);
2505                data->deleted = count_lines(one->data, one->size);
2506                data->added = count_lines(two->data, two->size);
2507        }
2508
2509        else if (!same_contents) {
2510                /* Crazy xdl interfaces.. */
2511                xpparam_t xpp;
2512                xdemitconf_t xecfg;
2513
2514                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2515                        die("unable to read files to diff");
2516
2517                memset(&xpp, 0, sizeof(xpp));
2518                memset(&xecfg, 0, sizeof(xecfg));
2519                xpp.flags = o->xdl_opts;
2520                xecfg.ctxlen = o->context;
2521                xecfg.interhunkctxlen = o->interhunkcontext;
2522                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2523                              &xpp, &xecfg);
2524        }
2525
2526        diff_free_filespec_data(one);
2527        diff_free_filespec_data(two);
2528}
2529
2530static void builtin_checkdiff(const char *name_a, const char *name_b,
2531                              const char *attr_path,
2532                              struct diff_filespec *one,
2533                              struct diff_filespec *two,
2534                              struct diff_options *o)
2535{
2536        mmfile_t mf1, mf2;
2537        struct checkdiff_t data;
2538
2539        if (!two)
2540                return;
2541
2542        memset(&data, 0, sizeof(data));
2543        data.filename = name_b ? name_b : name_a;
2544        data.lineno = 0;
2545        data.o = o;
2546        data.ws_rule = whitespace_rule(attr_path);
2547        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2548
2549        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2550                die("unable to read files to diff");
2551
2552        /*
2553         * All the other codepaths check both sides, but not checking
2554         * the "old" side here is deliberate.  We are checking the newly
2555         * introduced changes, and as long as the "new" side is text, we
2556         * can and should check what it introduces.
2557         */
2558        if (diff_filespec_is_binary(two))
2559                goto free_and_return;
2560        else {
2561                /* Crazy xdl interfaces.. */
2562                xpparam_t xpp;
2563                xdemitconf_t xecfg;
2564
2565                memset(&xpp, 0, sizeof(xpp));
2566                memset(&xecfg, 0, sizeof(xecfg));
2567                xecfg.ctxlen = 1; /* at least one context line */
2568                xpp.flags = 0;
2569                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2570                              &xpp, &xecfg);
2571
2572                if (data.ws_rule & WS_BLANK_AT_EOF) {
2573                        struct emit_callback ecbdata;
2574                        int blank_at_eof;
2575
2576                        ecbdata.ws_rule = data.ws_rule;
2577                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2578                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2579
2580                        if (blank_at_eof) {
2581                                static char *err;
2582                                if (!err)
2583                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2584                                fprintf(o->file, "%s:%d: %s.\n",
2585                                        data.filename, blank_at_eof, err);
2586                                data.status = 1; /* report errors */
2587                        }
2588                }
2589        }
2590 free_and_return:
2591        diff_free_filespec_data(one);
2592        diff_free_filespec_data(two);
2593        if (data.status)
2594                DIFF_OPT_SET(o, CHECK_FAILED);
2595}
2596
2597struct diff_filespec *alloc_filespec(const char *path)
2598{
2599        int namelen = strlen(path);
2600        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2601
2602        memset(spec, 0, sizeof(*spec));
2603        spec->path = (char *)(spec + 1);
2604        memcpy(spec->path, path, namelen+1);
2605        spec->count = 1;
2606        spec->is_binary = -1;
2607        return spec;
2608}
2609
2610void free_filespec(struct diff_filespec *spec)
2611{
2612        if (!--spec->count) {
2613                diff_free_filespec_data(spec);
2614                free(spec);
2615        }
2616}
2617
2618void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2619                   int sha1_valid, unsigned short mode)
2620{
2621        if (mode) {
2622                spec->mode = canon_mode(mode);
2623                hashcpy(spec->sha1, sha1);
2624                spec->sha1_valid = sha1_valid;
2625        }
2626}
2627
2628/*
2629 * Given a name and sha1 pair, if the index tells us the file in
2630 * the work tree has that object contents, return true, so that
2631 * prepare_temp_file() does not have to inflate and extract.
2632 */
2633static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2634{
2635        const struct cache_entry *ce;
2636        struct stat st;
2637        int pos, len;
2638
2639        /*
2640         * We do not read the cache ourselves here, because the
2641         * benchmark with my previous version that always reads cache
2642         * shows that it makes things worse for diff-tree comparing
2643         * two linux-2.6 kernel trees in an already checked out work
2644         * tree.  This is because most diff-tree comparisons deal with
2645         * only a small number of files, while reading the cache is
2646         * expensive for a large project, and its cost outweighs the
2647         * savings we get by not inflating the object to a temporary
2648         * file.  Practically, this code only helps when we are used
2649         * by diff-cache --cached, which does read the cache before
2650         * calling us.
2651         */
2652        if (!active_cache)
2653                return 0;
2654
2655        /* We want to avoid the working directory if our caller
2656         * doesn't need the data in a normal file, this system
2657         * is rather slow with its stat/open/mmap/close syscalls,
2658         * and the object is contained in a pack file.  The pack
2659         * is probably already open and will be faster to obtain
2660         * the data through than the working directory.  Loose
2661         * objects however would tend to be slower as they need
2662         * to be individually opened and inflated.
2663         */
2664        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2665                return 0;
2666
2667        len = strlen(name);
2668        pos = cache_name_pos(name, len);
2669        if (pos < 0)
2670                return 0;
2671        ce = active_cache[pos];
2672
2673        /*
2674         * This is not the sha1 we are looking for, or
2675         * unreusable because it is not a regular file.
2676         */
2677        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2678                return 0;
2679
2680        /*
2681         * If ce is marked as "assume unchanged", there is no
2682         * guarantee that work tree matches what we are looking for.
2683         */
2684        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2685                return 0;
2686
2687        /*
2688         * If ce matches the file in the work tree, we can reuse it.
2689         */
2690        if (ce_uptodate(ce) ||
2691            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2692                return 1;
2693
2694        return 0;
2695}
2696
2697static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2698{
2699        int len;
2700        char *data = xmalloc(100), *dirty = "";
2701
2702        /* Are we looking at the work tree? */
2703        if (s->dirty_submodule)
2704                dirty = "-dirty";
2705
2706        len = snprintf(data, 100,
2707                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2708        s->data = data;
2709        s->size = len;
2710        s->should_free = 1;
2711        if (size_only) {
2712                s->data = NULL;
2713                free(data);
2714        }
2715        return 0;
2716}
2717
2718/*
2719 * While doing rename detection and pickaxe operation, we may need to
2720 * grab the data for the blob (or file) for our own in-core comparison.
2721 * diff_filespec has data and size fields for this purpose.
2722 */
2723int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2724{
2725        int size_only = flags & CHECK_SIZE_ONLY;
2726        int err = 0;
2727        /*
2728         * demote FAIL to WARN to allow inspecting the situation
2729         * instead of refusing.
2730         */
2731        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2732                                    ? SAFE_CRLF_WARN
2733                                    : safe_crlf);
2734
2735        if (!DIFF_FILE_VALID(s))
2736                die("internal error: asking to populate invalid file.");
2737        if (S_ISDIR(s->mode))
2738                return -1;
2739
2740        if (s->data)
2741                return 0;
2742
2743        if (size_only && 0 < s->size)
2744                return 0;
2745
2746        if (S_ISGITLINK(s->mode))
2747                return diff_populate_gitlink(s, size_only);
2748
2749        if (!s->sha1_valid ||
2750            reuse_worktree_file(s->path, s->sha1, 0)) {
2751                struct strbuf buf = STRBUF_INIT;
2752                struct stat st;
2753                int fd;
2754
2755                if (lstat(s->path, &st) < 0) {
2756                        if (errno == ENOENT) {
2757                        err_empty:
2758                                err = -1;
2759                        empty:
2760                                s->data = (char *)"";
2761                                s->size = 0;
2762                                return err;
2763                        }
2764                }
2765                s->size = xsize_t(st.st_size);
2766                if (!s->size)
2767                        goto empty;
2768                if (S_ISLNK(st.st_mode)) {
2769                        struct strbuf sb = STRBUF_INIT;
2770
2771                        if (strbuf_readlink(&sb, s->path, s->size))
2772                                goto err_empty;
2773                        s->size = sb.len;
2774                        s->data = strbuf_detach(&sb, NULL);
2775                        s->should_free = 1;
2776                        return 0;
2777                }
2778                if (size_only)
2779                        return 0;
2780                if ((flags & CHECK_BINARY) &&
2781                    s->size > big_file_threshold && s->is_binary == -1) {
2782                        s->is_binary = 1;
2783                        return 0;
2784                }
2785                fd = open(s->path, O_RDONLY);
2786                if (fd < 0)
2787                        goto err_empty;
2788                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2789                close(fd);
2790                s->should_munmap = 1;
2791
2792                /*
2793                 * Convert from working tree format to canonical git format
2794                 */
2795                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2796                        size_t size = 0;
2797                        munmap(s->data, s->size);
2798                        s->should_munmap = 0;
2799                        s->data = strbuf_detach(&buf, &size);
2800                        s->size = size;
2801                        s->should_free = 1;
2802                }
2803        }
2804        else {
2805                enum object_type type;
2806                if (size_only || (flags & CHECK_BINARY)) {
2807                        type = sha1_object_info(s->sha1, &s->size);
2808                        if (type < 0)
2809                                die("unable to read %s", sha1_to_hex(s->sha1));
2810                        if (size_only)
2811                                return 0;
2812                        if (s->size > big_file_threshold && s->is_binary == -1) {
2813                                s->is_binary = 1;
2814                                return 0;
2815                        }
2816                }
2817                s->data = read_sha1_file(s->sha1, &type, &s->size);
2818                if (!s->data)
2819                        die("unable to read %s", sha1_to_hex(s->sha1));
2820                s->should_free = 1;
2821        }
2822        return 0;
2823}
2824
2825void diff_free_filespec_blob(struct diff_filespec *s)
2826{
2827        if (s->should_free)
2828                free(s->data);
2829        else if (s->should_munmap)
2830                munmap(s->data, s->size);
2831
2832        if (s->should_free || s->should_munmap) {
2833                s->should_free = s->should_munmap = 0;
2834                s->data = NULL;
2835        }
2836}
2837
2838void diff_free_filespec_data(struct diff_filespec *s)
2839{
2840        diff_free_filespec_blob(s);
2841        free(s->cnt_data);
2842        s->cnt_data = NULL;
2843}
2844
2845static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2846                           void *blob,
2847                           unsigned long size,
2848                           const unsigned char *sha1,
2849                           int mode)
2850{
2851        int fd;
2852        struct strbuf buf = STRBUF_INIT;
2853        struct strbuf template = STRBUF_INIT;
2854        char *path_dup = xstrdup(path);
2855        const char *base = basename(path_dup);
2856
2857        /* Generate "XXXXXX_basename.ext" */
2858        strbuf_addstr(&template, "XXXXXX_");
2859        strbuf_addstr(&template, base);
2860
2861        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2862                        strlen(base) + 1);
2863        if (fd < 0)
2864                die_errno("unable to create temp-file");
2865        if (convert_to_working_tree(path,
2866                        (const char *)blob, (size_t)size, &buf)) {
2867                blob = buf.buf;
2868                size = buf.len;
2869        }
2870        if (write_in_full(fd, blob, size) != size)
2871                die_errno("unable to write temp-file");
2872        close(fd);
2873        temp->name = temp->tmp_path;
2874        strcpy(temp->hex, sha1_to_hex(sha1));
2875        temp->hex[40] = 0;
2876        sprintf(temp->mode, "%06o", mode);
2877        strbuf_release(&buf);
2878        strbuf_release(&template);
2879        free(path_dup);
2880}
2881
2882static struct diff_tempfile *prepare_temp_file(const char *name,
2883                struct diff_filespec *one)
2884{
2885        struct diff_tempfile *temp = claim_diff_tempfile();
2886
2887        if (!DIFF_FILE_VALID(one)) {
2888        not_a_valid_file:
2889                /* A '-' entry produces this for file-2, and
2890                 * a '+' entry produces this for file-1.
2891                 */
2892                temp->name = "/dev/null";
2893                strcpy(temp->hex, ".");
2894                strcpy(temp->mode, ".");
2895                return temp;
2896        }
2897
2898        if (!remove_tempfile_installed) {
2899                atexit(remove_tempfile);
2900                sigchain_push_common(remove_tempfile_on_signal);
2901                remove_tempfile_installed = 1;
2902        }
2903
2904        if (!S_ISGITLINK(one->mode) &&
2905            (!one->sha1_valid ||
2906             reuse_worktree_file(name, one->sha1, 1))) {
2907                struct stat st;
2908                if (lstat(name, &st) < 0) {
2909                        if (errno == ENOENT)
2910                                goto not_a_valid_file;
2911                        die_errno("stat(%s)", name);
2912                }
2913                if (S_ISLNK(st.st_mode)) {
2914                        struct strbuf sb = STRBUF_INIT;
2915                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2916                                die_errno("readlink(%s)", name);
2917                        prep_temp_blob(name, temp, sb.buf, sb.len,
2918                                       (one->sha1_valid ?
2919                                        one->sha1 : null_sha1),
2920                                       (one->sha1_valid ?
2921                                        one->mode : S_IFLNK));
2922                        strbuf_release(&sb);
2923                }
2924                else {
2925                        /* we can borrow from the file in the work tree */
2926                        temp->name = name;
2927                        if (!one->sha1_valid)
2928                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2929                        else
2930                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2931                        /* Even though we may sometimes borrow the
2932                         * contents from the work tree, we always want
2933                         * one->mode.  mode is trustworthy even when
2934                         * !(one->sha1_valid), as long as
2935                         * DIFF_FILE_VALID(one).
2936                         */
2937                        sprintf(temp->mode, "%06o", one->mode);
2938                }
2939                return temp;
2940        }
2941        else {
2942                if (diff_populate_filespec(one, 0))
2943                        die("cannot read data blob for %s", one->path);
2944                prep_temp_blob(name, temp, one->data, one->size,
2945                               one->sha1, one->mode);
2946        }
2947        return temp;
2948}
2949
2950static void add_external_diff_name(struct argv_array *argv,
2951                                   const char *name,
2952                                   struct diff_filespec *df)
2953{
2954        struct diff_tempfile *temp = prepare_temp_file(name, df);
2955        argv_array_push(argv, temp->name);
2956        argv_array_push(argv, temp->hex);
2957        argv_array_push(argv, temp->mode);
2958}
2959
2960/* An external diff command takes:
2961 *
2962 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2963 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2964 *
2965 */
2966static void run_external_diff(const char *pgm,
2967                              const char *name,
2968                              const char *other,
2969                              struct diff_filespec *one,
2970                              struct diff_filespec *two,
2971                              const char *xfrm_msg,
2972                              int complete_rewrite,
2973                              struct diff_options *o)
2974{
2975        struct argv_array argv = ARGV_ARRAY_INIT;
2976        struct argv_array env = ARGV_ARRAY_INIT;
2977        struct diff_queue_struct *q = &diff_queued_diff;
2978
2979        argv_array_push(&argv, pgm);
2980        argv_array_push(&argv, name);
2981
2982        if (one && two) {
2983                add_external_diff_name(&argv, name, one);
2984                if (!other)
2985                        add_external_diff_name(&argv, name, two);
2986                else {
2987                        add_external_diff_name(&argv, other, two);
2988                        argv_array_push(&argv, other);
2989                        argv_array_push(&argv, xfrm_msg);
2990                }
2991        }
2992
2993        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2994        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2995
2996        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2997                die(_("external diff died, stopping at %s"), name);
2998
2999        remove_tempfile();
3000        argv_array_clear(&argv);
3001        argv_array_clear(&env);
3002}
3003
3004static int similarity_index(struct diff_filepair *p)
3005{
3006        return p->score * 100 / MAX_SCORE;
3007}
3008
3009static void fill_metainfo(struct strbuf *msg,
3010                          const char *name,
3011                          const char *other,
3012                          struct diff_filespec *one,
3013                          struct diff_filespec *two,
3014                          struct diff_options *o,
3015                          struct diff_filepair *p,
3016                          int *must_show_header,
3017                          int use_color)
3018{
3019        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3020        const char *reset = diff_get_color(use_color, DIFF_RESET);
3021        const char *line_prefix = diff_line_prefix(o);
3022
3023        *must_show_header = 1;
3024        strbuf_init(msg, PATH_MAX * 2 + 300);
3025        switch (p->status) {
3026        case DIFF_STATUS_COPIED:
3027                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3028                            line_prefix, set, similarity_index(p));
3029                strbuf_addf(msg, "%s\n%s%scopy from ",
3030                            reset,  line_prefix, set);
3031                quote_c_style(name, msg, NULL, 0);
3032                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3033                quote_c_style(other, msg, NULL, 0);
3034                strbuf_addf(msg, "%s\n", reset);
3035                break;
3036        case DIFF_STATUS_RENAMED:
3037                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3038                            line_prefix, set, similarity_index(p));
3039                strbuf_addf(msg, "%s\n%s%srename from ",
3040                            reset, line_prefix, set);
3041                quote_c_style(name, msg, NULL, 0);
3042                strbuf_addf(msg, "%s\n%s%srename to ",
3043                            reset, line_prefix, set);
3044                quote_c_style(other, msg, NULL, 0);
3045                strbuf_addf(msg, "%s\n", reset);
3046                break;
3047        case DIFF_STATUS_MODIFIED:
3048                if (p->score) {
3049                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3050                                    line_prefix,
3051                                    set, similarity_index(p), reset);
3052                        break;
3053                }
3054                /* fallthru */
3055        default:
3056                *must_show_header = 0;
3057        }
3058        if (one && two && hashcmp(one->sha1, two->sha1)) {
3059                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3060
3061                if (DIFF_OPT_TST(o, BINARY)) {
3062                        mmfile_t mf;
3063                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3064                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3065                                abbrev = 40;
3066                }
3067                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3068                            find_unique_abbrev(one->sha1, abbrev));
3069                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3070                if (one->mode == two->mode)
3071                        strbuf_addf(msg, " %06o", one->mode);
3072                strbuf_addf(msg, "%s\n", reset);
3073        }
3074}
3075
3076static void run_diff_cmd(const char *pgm,
3077                         const char *name,
3078                         const char *other,
3079                         const char *attr_path,
3080                         struct diff_filespec *one,
3081                         struct diff_filespec *two,
3082                         struct strbuf *msg,
3083                         struct diff_options *o,
3084                         struct diff_filepair *p)
3085{
3086        const char *xfrm_msg = NULL;
3087        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3088        int must_show_header = 0;
3089
3090
3091        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3092                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3093                if (drv && drv->external)
3094                        pgm = drv->external;
3095        }
3096
3097        if (msg) {
3098                /*
3099                 * don't use colors when the header is intended for an
3100                 * external diff driver
3101                 */
3102                fill_metainfo(msg, name, other, one, two, o, p,
3103                              &must_show_header,
3104                              want_color(o->use_color) && !pgm);
3105                xfrm_msg = msg->len ? msg->buf : NULL;
3106        }
3107
3108        if (pgm) {
3109                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3110                                  complete_rewrite, o);
3111                return;
3112        }
3113        if (one && two)
3114                builtin_diff(name, other ? other : name,
3115                             one, two, xfrm_msg, must_show_header,
3116                             o, complete_rewrite);
3117        else
3118                fprintf(o->file, "* Unmerged path %s\n", name);
3119}
3120
3121static void diff_fill_sha1_info(struct diff_filespec *one)
3122{
3123        if (DIFF_FILE_VALID(one)) {
3124                if (!one->sha1_valid) {
3125                        struct stat st;
3126                        if (one->is_stdin) {
3127                                hashcpy(one->sha1, null_sha1);
3128                                return;
3129                        }
3130                        if (lstat(one->path, &st) < 0)
3131                                die_errno("stat '%s'", one->path);
3132                        if (index_path(one->sha1, one->path, &st, 0))
3133                                die("cannot hash %s", one->path);
3134                }
3135        }
3136        else
3137                hashclr(one->sha1);
3138}
3139
3140static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3141{
3142        /* Strip the prefix but do not molest /dev/null and absolute paths */
3143        if (*namep && **namep != '/') {
3144                *namep += prefix_length;
3145                if (**namep == '/')
3146                        ++*namep;
3147        }
3148        if (*otherp && **otherp != '/') {
3149                *otherp += prefix_length;
3150                if (**otherp == '/')
3151                        ++*otherp;
3152        }
3153}
3154
3155static void run_diff(struct diff_filepair *p, struct diff_options *o)
3156{
3157        const char *pgm = external_diff();
3158        struct strbuf msg;
3159        struct diff_filespec *one = p->one;
3160        struct diff_filespec *two = p->two;
3161        const char *name;
3162        const char *other;
3163        const char *attr_path;
3164
3165        name  = p->one->path;
3166        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3167        attr_path = name;
3168        if (o->prefix_length)
3169                strip_prefix(o->prefix_length, &name, &other);
3170
3171        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3172                pgm = NULL;
3173
3174        if (DIFF_PAIR_UNMERGED(p)) {
3175                run_diff_cmd(pgm, name, NULL, attr_path,
3176                             NULL, NULL, NULL, o, p);
3177                return;
3178        }
3179
3180        diff_fill_sha1_info(one);
3181        diff_fill_sha1_info(two);
3182
3183        if (!pgm &&
3184            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3185            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3186                /*
3187                 * a filepair that changes between file and symlink
3188                 * needs to be split into deletion and creation.
3189                 */
3190                struct diff_filespec *null = alloc_filespec(two->path);
3191                run_diff_cmd(NULL, name, other, attr_path,
3192                             one, null, &msg, o, p);
3193                free(null);
3194                strbuf_release(&msg);
3195
3196                null = alloc_filespec(one->path);
3197                run_diff_cmd(NULL, name, other, attr_path,
3198                             null, two, &msg, o, p);
3199                free(null);
3200        }
3201        else
3202                run_diff_cmd(pgm, name, other, attr_path,
3203                             one, two, &msg, o, p);
3204
3205        strbuf_release(&msg);
3206}
3207
3208static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3209                         struct diffstat_t *diffstat)
3210{
3211        const char *name;
3212        const char *other;
3213
3214        if (DIFF_PAIR_UNMERGED(p)) {
3215                /* unmerged */
3216                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3217                return;
3218        }
3219
3220        name = p->one->path;
3221        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3222
3223        if (o->prefix_length)
3224                strip_prefix(o->prefix_length, &name, &other);
3225
3226        diff_fill_sha1_info(p->one);
3227        diff_fill_sha1_info(p->two);
3228
3229        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3230}
3231
3232static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3233{
3234        const char *name;
3235        const char *other;
3236        const char *attr_path;
3237
3238        if (DIFF_PAIR_UNMERGED(p)) {
3239                /* unmerged */
3240                return;
3241        }
3242
3243        name = p->one->path;
3244        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3245        attr_path = other ? other : name;
3246
3247        if (o->prefix_length)
3248                strip_prefix(o->prefix_length, &name, &other);
3249
3250        diff_fill_sha1_info(p->one);
3251        diff_fill_sha1_info(p->two);
3252
3253        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3254}
3255
3256void diff_setup(struct diff_options *options)
3257{
3258        memcpy(options, &default_diff_options, sizeof(*options));
3259
3260        options->file = stdout;
3261
3262        options->line_termination = '\n';
3263        options->break_opt = -1;
3264        options->rename_limit = -1;
3265        options->dirstat_permille = diff_dirstat_permille_default;
3266        options->context = diff_context_default;
3267        options->ws_error_highlight = WSEH_NEW;
3268        DIFF_OPT_SET(options, RENAME_EMPTY);
3269
3270        /* pathchange left =NULL by default */
3271        options->change = diff_change;
3272        options->add_remove = diff_addremove;
3273        options->use_color = diff_use_color_default;
3274        options->detect_rename = diff_detect_rename_default;
3275        options->xdl_opts |= diff_algorithm;
3276
3277        options->orderfile = diff_order_file_cfg;
3278
3279        if (diff_no_prefix) {
3280                options->a_prefix = options->b_prefix = "";
3281        } else if (!diff_mnemonic_prefix) {
3282                options->a_prefix = "a/";
3283                options->b_prefix = "b/";
3284        }
3285}
3286
3287void diff_setup_done(struct diff_options *options)
3288{
3289        int count = 0;
3290
3291        if (options->set_default)
3292                options->set_default(options);
3293
3294        if (options->output_format & DIFF_FORMAT_NAME)
3295                count++;
3296        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3297                count++;
3298        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3299                count++;
3300        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3301                count++;
3302        if (count > 1)
3303                die("--name-only, --name-status, --check and -s are mutually exclusive");
3304
3305        /*
3306         * Most of the time we can say "there are changes"
3307         * only by checking if there are changed paths, but
3308         * --ignore-whitespace* options force us to look
3309         * inside contents.
3310         */
3311
3312        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3313            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3314            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3315                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3316        else
3317                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3318
3319        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3320                options->detect_rename = DIFF_DETECT_COPY;
3321
3322        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3323                options->prefix = NULL;
3324        if (options->prefix)
3325                options->prefix_length = strlen(options->prefix);
3326        else
3327                options->prefix_length = 0;
3328
3329        if (options->output_format & (DIFF_FORMAT_NAME |
3330                                      DIFF_FORMAT_NAME_STATUS |
3331                                      DIFF_FORMAT_CHECKDIFF |
3332                                      DIFF_FORMAT_NO_OUTPUT))
3333                options->output_format &= ~(DIFF_FORMAT_RAW |
3334                                            DIFF_FORMAT_NUMSTAT |
3335                                            DIFF_FORMAT_DIFFSTAT |
3336                                            DIFF_FORMAT_SHORTSTAT |
3337                                            DIFF_FORMAT_DIRSTAT |
3338                                            DIFF_FORMAT_SUMMARY |
3339                                            DIFF_FORMAT_PATCH);
3340
3341        /*
3342         * These cases always need recursive; we do not drop caller-supplied
3343         * recursive bits for other formats here.
3344         */
3345        if (options->output_format & (DIFF_FORMAT_PATCH |
3346                                      DIFF_FORMAT_NUMSTAT |
3347                                      DIFF_FORMAT_DIFFSTAT |
3348                                      DIFF_FORMAT_SHORTSTAT |
3349                                      DIFF_FORMAT_DIRSTAT |
3350                                      DIFF_FORMAT_SUMMARY |
3351                                      DIFF_FORMAT_CHECKDIFF))
3352                DIFF_OPT_SET(options, RECURSIVE);
3353        /*
3354         * Also pickaxe would not work very well if you do not say recursive
3355         */
3356        if (options->pickaxe)
3357                DIFF_OPT_SET(options, RECURSIVE);
3358        /*
3359         * When patches are generated, submodules diffed against the work tree
3360         * must be checked for dirtiness too so it can be shown in the output
3361         */
3362        if (options->output_format & DIFF_FORMAT_PATCH)
3363                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3364
3365        if (options->detect_rename && options->rename_limit < 0)
3366                options->rename_limit = diff_rename_limit_default;
3367        if (options->setup & DIFF_SETUP_USE_CACHE) {
3368                if (!active_cache)
3369                        /* read-cache does not die even when it fails
3370                         * so it is safe for us to do this here.  Also
3371                         * it does not smudge active_cache or active_nr
3372                         * when it fails, so we do not have to worry about
3373                         * cleaning it up ourselves either.
3374                         */
3375                        read_cache();
3376        }
3377        if (options->abbrev <= 0 || 40 < options->abbrev)
3378                options->abbrev = 40; /* full */
3379
3380        /*
3381         * It does not make sense to show the first hit we happened
3382         * to have found.  It does not make sense not to return with
3383         * exit code in such a case either.
3384         */
3385        if (DIFF_OPT_TST(options, QUICK)) {
3386                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3387                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3388        }
3389
3390        options->diff_path_counter = 0;
3391
3392        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3393                die(_("--follow requires exactly one pathspec"));
3394}
3395
3396static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3397{
3398        char c, *eq;
3399        int len;
3400
3401        if (*arg != '-')
3402                return 0;
3403        c = *++arg;
3404        if (!c)
3405                return 0;
3406        if (c == arg_short) {
3407                c = *++arg;
3408                if (!c)
3409                        return 1;
3410                if (val && isdigit(c)) {
3411                        char *end;
3412                        int n = strtoul(arg, &end, 10);
3413                        if (*end)
3414                                return 0;
3415                        *val = n;
3416                        return 1;
3417                }
3418                return 0;
3419        }
3420        if (c != '-')
3421                return 0;
3422        arg++;
3423        eq = strchrnul(arg, '=');
3424        len = eq - arg;
3425        if (!len || strncmp(arg, arg_long, len))
3426                return 0;
3427        if (*eq) {
3428                int n;
3429                char *end;
3430                if (!isdigit(*++eq))
3431                        return 0;
3432                n = strtoul(eq, &end, 10);
3433                if (*end)
3434                        return 0;
3435                *val = n;
3436        }
3437        return 1;
3438}
3439
3440static int diff_scoreopt_parse(const char *opt);
3441
3442static inline int short_opt(char opt, const char **argv,
3443                            const char **optarg)
3444{
3445        const char *arg = argv[0];
3446        if (arg[0] != '-' || arg[1] != opt)
3447                return 0;
3448        if (arg[2] != '\0') {
3449                *optarg = arg + 2;
3450                return 1;
3451        }
3452        if (!argv[1])
3453                die("Option '%c' requires a value", opt);
3454        *optarg = argv[1];
3455        return 2;
3456}
3457
3458int parse_long_opt(const char *opt, const char **argv,
3459                   const char **optarg)
3460{
3461        const char *arg = argv[0];
3462        if (!skip_prefix(arg, "--", &arg))
3463                return 0;
3464        if (!skip_prefix(arg, opt, &arg))
3465                return 0;
3466        if (*arg == '=') { /* stuck form: --option=value */
3467                *optarg = arg + 1;
3468                return 1;
3469        }
3470        if (*arg != '\0')
3471                return 0;
3472        /* separate form: --option value */
3473        if (!argv[1])
3474                die("Option '--%s' requires a value", opt);
3475        *optarg = argv[1];
3476        return 2;
3477}
3478
3479static int stat_opt(struct diff_options *options, const char **av)
3480{
3481        const char *arg = av[0];
3482        char *end;
3483        int width = options->stat_width;
3484        int name_width = options->stat_name_width;
3485        int graph_width = options->stat_graph_width;
3486        int count = options->stat_count;
3487        int argcount = 1;
3488
3489        if (!skip_prefix(arg, "--stat", &arg))
3490                die("BUG: stat option does not begin with --stat: %s", arg);
3491        end = (char *)arg;
3492
3493        switch (*arg) {
3494        case '-':
3495                if (skip_prefix(arg, "-width", &arg)) {
3496                        if (*arg == '=')
3497                                width = strtoul(arg + 1, &end, 10);
3498                        else if (!*arg && !av[1])
3499                                die("Option '--stat-width' requires a value");
3500                        else if (!*arg) {
3501                                width = strtoul(av[1], &end, 10);
3502                                argcount = 2;
3503                        }
3504                } else if (skip_prefix(arg, "-name-width", &arg)) {
3505                        if (*arg == '=')
3506                                name_width = strtoul(arg + 1, &end, 10);
3507                        else if (!*arg && !av[1])
3508                                die("Option '--stat-name-width' requires a value");
3509                        else if (!*arg) {
3510                                name_width = strtoul(av[1], &end, 10);
3511                                argcount = 2;
3512                        }
3513                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3514                        if (*arg == '=')
3515                                graph_width = strtoul(arg + 1, &end, 10);
3516                        else if (!*arg && !av[1])
3517                                die("Option '--stat-graph-width' requires a value");
3518                        else if (!*arg) {
3519                                graph_width = strtoul(av[1], &end, 10);
3520                                argcount = 2;
3521                        }
3522                } else if (skip_prefix(arg, "-count", &arg)) {
3523                        if (*arg == '=')
3524                                count = strtoul(arg + 1, &end, 10);
3525                        else if (!*arg && !av[1])
3526                                die("Option '--stat-count' requires a value");
3527                        else if (!*arg) {
3528                                count = strtoul(av[1], &end, 10);
3529                                argcount = 2;
3530                        }
3531                }
3532                break;
3533        case '=':
3534                width = strtoul(arg+1, &end, 10);
3535                if (*end == ',')
3536                        name_width = strtoul(end+1, &end, 10);
3537                if (*end == ',')
3538                        count = strtoul(end+1, &end, 10);
3539        }
3540
3541        /* Important! This checks all the error cases! */
3542        if (*end)
3543                return 0;
3544        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3545        options->stat_name_width = name_width;
3546        options->stat_graph_width = graph_width;
3547        options->stat_width = width;
3548        options->stat_count = count;
3549        return argcount;
3550}
3551
3552static int parse_dirstat_opt(struct diff_options *options, const char *params)
3553{
3554        struct strbuf errmsg = STRBUF_INIT;
3555        if (parse_dirstat_params(options, params, &errmsg))
3556                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3557                    errmsg.buf);
3558        strbuf_release(&errmsg);
3559        /*
3560         * The caller knows a dirstat-related option is given from the command
3561         * line; allow it to say "return this_function();"
3562         */
3563        options->output_format |= DIFF_FORMAT_DIRSTAT;
3564        return 1;
3565}
3566
3567static int parse_submodule_opt(struct diff_options *options, const char *value)
3568{
3569        if (parse_submodule_params(options, value))
3570                die(_("Failed to parse --submodule option parameter: '%s'"),
3571                        value);
3572        return 1;
3573}
3574
3575static const char diff_status_letters[] = {
3576        DIFF_STATUS_ADDED,
3577        DIFF_STATUS_COPIED,
3578        DIFF_STATUS_DELETED,
3579        DIFF_STATUS_MODIFIED,
3580        DIFF_STATUS_RENAMED,
3581        DIFF_STATUS_TYPE_CHANGED,
3582        DIFF_STATUS_UNKNOWN,
3583        DIFF_STATUS_UNMERGED,
3584        DIFF_STATUS_FILTER_AON,
3585        DIFF_STATUS_FILTER_BROKEN,
3586        '\0',
3587};
3588
3589static unsigned int filter_bit['Z' + 1];
3590
3591static void prepare_filter_bits(void)
3592{
3593        int i;
3594
3595        if (!filter_bit[DIFF_STATUS_ADDED]) {
3596                for (i = 0; diff_status_letters[i]; i++)
3597                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3598        }
3599}
3600
3601static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3602{
3603        return opt->filter & filter_bit[(int) status];
3604}
3605
3606static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3607{
3608        int i, optch;
3609
3610        prepare_filter_bits();
3611
3612        /*
3613         * If there is a negation e.g. 'd' in the input, and we haven't
3614         * initialized the filter field with another --diff-filter, start
3615         * from full set of bits, except for AON.
3616         */
3617        if (!opt->filter) {
3618                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3619                        if (optch < 'a' || 'z' < optch)
3620                                continue;
3621                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3622                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3623                        break;
3624                }
3625        }
3626
3627        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3628                unsigned int bit;
3629                int negate;
3630
3631                if ('a' <= optch && optch <= 'z') {
3632                        negate = 1;
3633                        optch = toupper(optch);
3634                } else {
3635                        negate = 0;
3636                }
3637
3638                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3639                if (!bit)
3640                        return optarg[i];
3641                if (negate)
3642                        opt->filter &= ~bit;
3643                else
3644                        opt->filter |= bit;
3645        }
3646        return 0;
3647}
3648
3649static void enable_patch_output(int *fmt) {
3650        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3651        *fmt |= DIFF_FORMAT_PATCH;
3652}
3653
3654static int parse_one_token(const char **arg, const char *token)
3655{
3656        const char *rest;
3657        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3658                *arg = rest;
3659                return 1;
3660        }
3661        return 0;
3662}
3663
3664static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3665{
3666        const char *orig_arg = arg;
3667        unsigned val = 0;
3668        while (*arg) {
3669                if (parse_one_token(&arg, "none"))
3670                        val = 0;
3671                else if (parse_one_token(&arg, "default"))
3672                        val = WSEH_NEW;
3673                else if (parse_one_token(&arg, "all"))
3674                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3675                else if (parse_one_token(&arg, "new"))
3676                        val |= WSEH_NEW;
3677                else if (parse_one_token(&arg, "old"))
3678                        val |= WSEH_OLD;
3679                else if (parse_one_token(&arg, "context"))
3680                        val |= WSEH_CONTEXT;
3681                else {
3682                        error("unknown value after ws-error-highlight=%.*s",
3683                              (int)(arg - orig_arg), orig_arg);
3684                        return 0;
3685                }
3686                if (*arg)
3687                        arg++;
3688        }
3689        opt->ws_error_highlight = val;
3690        return 1;
3691}
3692
3693int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3694{
3695        const char *arg = av[0];
3696        const char *optarg;
3697        int argcount;
3698
3699        /* Output format options */
3700        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3701            || opt_arg(arg, 'U', "unified", &options->context))
3702                enable_patch_output(&options->output_format);
3703        else if (!strcmp(arg, "--raw"))
3704                options->output_format |= DIFF_FORMAT_RAW;
3705        else if (!strcmp(arg, "--patch-with-raw")) {
3706                enable_patch_output(&options->output_format);
3707                options->output_format |= DIFF_FORMAT_RAW;
3708        } else if (!strcmp(arg, "--numstat"))
3709                options->output_format |= DIFF_FORMAT_NUMSTAT;
3710        else if (!strcmp(arg, "--shortstat"))
3711                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3712        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3713                return parse_dirstat_opt(options, "");
3714        else if (skip_prefix(arg, "-X", &arg))
3715                return parse_dirstat_opt(options, arg);
3716        else if (skip_prefix(arg, "--dirstat=", &arg))
3717                return parse_dirstat_opt(options, arg);
3718        else if (!strcmp(arg, "--cumulative"))
3719                return parse_dirstat_opt(options, "cumulative");
3720        else if (!strcmp(arg, "--dirstat-by-file"))
3721                return parse_dirstat_opt(options, "files");
3722        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3723                parse_dirstat_opt(options, "files");
3724                return parse_dirstat_opt(options, arg);
3725        }
3726        else if (!strcmp(arg, "--check"))
3727                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3728        else if (!strcmp(arg, "--summary"))
3729                options->output_format |= DIFF_FORMAT_SUMMARY;
3730        else if (!strcmp(arg, "--patch-with-stat")) {
3731                enable_patch_output(&options->output_format);
3732                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3733        } else if (!strcmp(arg, "--name-only"))
3734                options->output_format |= DIFF_FORMAT_NAME;
3735        else if (!strcmp(arg, "--name-status"))
3736                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3737        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3738                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3739        else if (starts_with(arg, "--stat"))
3740                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3741                return stat_opt(options, av);
3742
3743        /* renames options */
3744        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3745                 !strcmp(arg, "--break-rewrites")) {
3746                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3747                        return error("invalid argument to -B: %s", arg+2);
3748        }
3749        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3750                 !strcmp(arg, "--find-renames")) {
3751                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3752                        return error("invalid argument to -M: %s", arg+2);
3753                options->detect_rename = DIFF_DETECT_RENAME;
3754        }
3755        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3756                options->irreversible_delete = 1;
3757        }
3758        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3759                 !strcmp(arg, "--find-copies")) {
3760                if (options->detect_rename == DIFF_DETECT_COPY)
3761                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3762                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3763                        return error("invalid argument to -C: %s", arg+2);
3764                options->detect_rename = DIFF_DETECT_COPY;
3765        }
3766        else if (!strcmp(arg, "--no-renames"))
3767                options->detect_rename = 0;
3768        else if (!strcmp(arg, "--rename-empty"))
3769                DIFF_OPT_SET(options, RENAME_EMPTY);
3770        else if (!strcmp(arg, "--no-rename-empty"))
3771                DIFF_OPT_CLR(options, RENAME_EMPTY);
3772        else if (!strcmp(arg, "--relative"))
3773                DIFF_OPT_SET(options, RELATIVE_NAME);
3774        else if (skip_prefix(arg, "--relative=", &arg)) {
3775                DIFF_OPT_SET(options, RELATIVE_NAME);
3776                options->prefix = arg;
3777        }
3778
3779        /* xdiff options */
3780        else if (!strcmp(arg, "--minimal"))
3781                DIFF_XDL_SET(options, NEED_MINIMAL);
3782        else if (!strcmp(arg, "--no-minimal"))
3783                DIFF_XDL_CLR(options, NEED_MINIMAL);
3784        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3785                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3786        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3787                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3788        else if (!strcmp(arg, "--ignore-space-at-eol"))
3789                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3790        else if (!strcmp(arg, "--ignore-blank-lines"))
3791                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3792        else if (!strcmp(arg, "--patience"))
3793                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3794        else if (!strcmp(arg, "--histogram"))
3795                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3796        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3797                long value = parse_algorithm_value(optarg);
3798                if (value < 0)
3799                        return error("option diff-algorithm accepts \"myers\", "
3800                                     "\"minimal\", \"patience\" and \"histogram\"");
3801                /* clear out previous settings */
3802                DIFF_XDL_CLR(options, NEED_MINIMAL);
3803                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3804                options->xdl_opts |= value;
3805                return argcount;
3806        }
3807
3808        /* flags options */
3809        else if (!strcmp(arg, "--binary")) {
3810                enable_patch_output(&options->output_format);
3811                DIFF_OPT_SET(options, BINARY);
3812        }
3813        else if (!strcmp(arg, "--full-index"))
3814                DIFF_OPT_SET(options, FULL_INDEX);
3815        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3816                DIFF_OPT_SET(options, TEXT);
3817        else if (!strcmp(arg, "-R"))
3818                DIFF_OPT_SET(options, REVERSE_DIFF);
3819        else if (!strcmp(arg, "--find-copies-harder"))
3820                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3821        else if (!strcmp(arg, "--follow"))
3822                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3823        else if (!strcmp(arg, "--no-follow")) {
3824                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3825                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3826        } else if (!strcmp(arg, "--color"))
3827                options->use_color = 1;
3828        else if (skip_prefix(arg, "--color=", &arg)) {
3829                int value = git_config_colorbool(NULL, arg);
3830                if (value < 0)
3831                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3832                options->use_color = value;
3833        }
3834        else if (!strcmp(arg, "--no-color"))
3835                options->use_color = 0;
3836        else if (!strcmp(arg, "--color-words")) {
3837                options->use_color = 1;
3838                options->word_diff = DIFF_WORDS_COLOR;
3839        }
3840        else if (skip_prefix(arg, "--color-words=", &arg)) {
3841                options->use_color = 1;
3842                options->word_diff = DIFF_WORDS_COLOR;
3843                options->word_regex = arg;
3844        }
3845        else if (!strcmp(arg, "--word-diff")) {
3846                if (options->word_diff == DIFF_WORDS_NONE)
3847                        options->word_diff = DIFF_WORDS_PLAIN;
3848        }
3849        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3850                if (!strcmp(arg, "plain"))
3851                        options->word_diff = DIFF_WORDS_PLAIN;
3852                else if (!strcmp(arg, "color")) {
3853                        options->use_color = 1;
3854                        options->word_diff = DIFF_WORDS_COLOR;
3855                }
3856                else if (!strcmp(arg, "porcelain"))
3857                        options->word_diff = DIFF_WORDS_PORCELAIN;
3858                else if (!strcmp(arg, "none"))
3859                        options->word_diff = DIFF_WORDS_NONE;
3860                else
3861                        die("bad --word-diff argument: %s", arg);
3862        }
3863        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3864                if (options->word_diff == DIFF_WORDS_NONE)
3865                        options->word_diff = DIFF_WORDS_PLAIN;
3866                options->word_regex = optarg;
3867                return argcount;
3868        }
3869        else if (!strcmp(arg, "--exit-code"))
3870                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3871        else if (!strcmp(arg, "--quiet"))
3872                DIFF_OPT_SET(options, QUICK);
3873        else if (!strcmp(arg, "--ext-diff"))
3874                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3875        else if (!strcmp(arg, "--no-ext-diff"))
3876                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3877        else if (!strcmp(arg, "--textconv"))
3878                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3879        else if (!strcmp(arg, "--no-textconv"))
3880                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3881        else if (!strcmp(arg, "--ignore-submodules")) {
3882                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3883                handle_ignore_submodules_arg(options, "all");
3884        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3885                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3886                handle_ignore_submodules_arg(options, arg);
3887        } else if (!strcmp(arg, "--submodule"))
3888                DIFF_OPT_SET(options, SUBMODULE_LOG);
3889        else if (skip_prefix(arg, "--submodule=", &arg))
3890                return parse_submodule_opt(options, arg);
3891        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3892                return parse_ws_error_highlight(options, arg);
3893
3894        /* misc options */
3895        else if (!strcmp(arg, "-z"))
3896                options->line_termination = 0;
3897        else if ((argcount = short_opt('l', av, &optarg))) {
3898                options->rename_limit = strtoul(optarg, NULL, 10);
3899                return argcount;
3900        }
3901        else if ((argcount = short_opt('S', av, &optarg))) {
3902                options->pickaxe = optarg;
3903                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3904                return argcount;
3905        } else if ((argcount = short_opt('G', av, &optarg))) {
3906                options->pickaxe = optarg;
3907                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3908                return argcount;
3909        }
3910        else if (!strcmp(arg, "--pickaxe-all"))
3911                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3912        else if (!strcmp(arg, "--pickaxe-regex"))
3913                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3914        else if ((argcount = short_opt('O', av, &optarg))) {
3915                options->orderfile = optarg;
3916                return argcount;
3917        }
3918        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3919                int offending = parse_diff_filter_opt(optarg, options);
3920                if (offending)
3921                        die("unknown change class '%c' in --diff-filter=%s",
3922                            offending, optarg);
3923                return argcount;
3924        }
3925        else if (!strcmp(arg, "--abbrev"))
3926                options->abbrev = DEFAULT_ABBREV;
3927        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3928                options->abbrev = strtoul(arg, NULL, 10);
3929                if (options->abbrev < MINIMUM_ABBREV)
3930                        options->abbrev = MINIMUM_ABBREV;
3931                else if (40 < options->abbrev)
3932                        options->abbrev = 40;
3933        }
3934        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3935                options->a_prefix = optarg;
3936                return argcount;
3937        }
3938        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3939                options->b_prefix = optarg;
3940                return argcount;
3941        }
3942        else if (!strcmp(arg, "--no-prefix"))
3943                options->a_prefix = options->b_prefix = "";
3944        else if (opt_arg(arg, '\0', "inter-hunk-context",
3945                         &options->interhunkcontext))
3946                ;
3947        else if (!strcmp(arg, "-W"))
3948                DIFF_OPT_SET(options, FUNCCONTEXT);
3949        else if (!strcmp(arg, "--function-context"))
3950                DIFF_OPT_SET(options, FUNCCONTEXT);
3951        else if (!strcmp(arg, "--no-function-context"))
3952                DIFF_OPT_CLR(options, FUNCCONTEXT);
3953        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3954                options->file = fopen(optarg, "w");
3955                if (!options->file)
3956                        die_errno("Could not open '%s'", optarg);
3957                options->close_file = 1;
3958                return argcount;
3959        } else
3960                return 0;
3961        return 1;
3962}
3963
3964int parse_rename_score(const char **cp_p)
3965{
3966        unsigned long num, scale;
3967        int ch, dot;
3968        const char *cp = *cp_p;
3969
3970        num = 0;
3971        scale = 1;
3972        dot = 0;
3973        for (;;) {
3974                ch = *cp;
3975                if ( !dot && ch == '.' ) {
3976                        scale = 1;
3977                        dot = 1;
3978                } else if ( ch == '%' ) {
3979                        scale = dot ? scale*100 : 100;
3980                        cp++;   /* % is always at the end */
3981                        break;
3982                } else if ( ch >= '0' && ch <= '9' ) {
3983                        if ( scale < 100000 ) {
3984                                scale *= 10;
3985                                num = (num*10) + (ch-'0');
3986                        }
3987                } else {
3988                        break;
3989                }
3990                cp++;
3991        }
3992        *cp_p = cp;
3993
3994        /* user says num divided by scale and we say internally that
3995         * is MAX_SCORE * num / scale.
3996         */
3997        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3998}
3999
4000static int diff_scoreopt_parse(const char *opt)
4001{
4002        int opt1, opt2, cmd;
4003
4004        if (*opt++ != '-')
4005                return -1;
4006        cmd = *opt++;
4007        if (cmd == '-') {
4008                /* convert the long-form arguments into short-form versions */
4009                if (skip_prefix(opt, "break-rewrites", &opt)) {
4010                        if (*opt == 0 || *opt++ == '=')
4011                                cmd = 'B';
4012                } else if (skip_prefix(opt, "find-copies", &opt)) {
4013                        if (*opt == 0 || *opt++ == '=')
4014                                cmd = 'C';
4015                } else if (skip_prefix(opt, "find-renames", &opt)) {
4016                        if (*opt == 0 || *opt++ == '=')
4017                                cmd = 'M';
4018                }
4019        }
4020        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4021                return -1; /* that is not a -M, -C, or -B option */
4022
4023        opt1 = parse_rename_score(&opt);
4024        if (cmd != 'B')
4025                opt2 = 0;
4026        else {
4027                if (*opt == 0)
4028                        opt2 = 0;
4029                else if (*opt != '/')
4030                        return -1; /* we expect -B80/99 or -B80 */
4031                else {
4032                        opt++;
4033                        opt2 = parse_rename_score(&opt);
4034                }
4035        }
4036        if (*opt != 0)
4037                return -1;
4038        return opt1 | (opt2 << 16);
4039}
4040
4041struct diff_queue_struct diff_queued_diff;
4042
4043void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4044{
4045        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4046        queue->queue[queue->nr++] = dp;
4047}
4048
4049struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4050                                 struct diff_filespec *one,
4051                                 struct diff_filespec *two)
4052{
4053        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4054        dp->one = one;
4055        dp->two = two;
4056        if (queue)
4057                diff_q(queue, dp);
4058        return dp;
4059}
4060
4061void diff_free_filepair(struct diff_filepair *p)
4062{
4063        free_filespec(p->one);
4064        free_filespec(p->two);
4065        free(p);
4066}
4067
4068/* This is different from find_unique_abbrev() in that
4069 * it stuffs the result with dots for alignment.
4070 */
4071const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4072{
4073        int abblen;
4074        const char *abbrev;
4075        if (len == 40)
4076                return sha1_to_hex(sha1);
4077
4078        abbrev = find_unique_abbrev(sha1, len);
4079        abblen = strlen(abbrev);
4080        if (abblen < 37) {
4081                static char hex[41];
4082                if (len < abblen && abblen <= len + 2)
4083                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
4084                else
4085                        sprintf(hex, "%s...", abbrev);
4086                return hex;
4087        }
4088        return sha1_to_hex(sha1);
4089}
4090
4091static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4092{
4093        int line_termination = opt->line_termination;
4094        int inter_name_termination = line_termination ? '\t' : '\0';
4095
4096        fprintf(opt->file, "%s", diff_line_prefix(opt));
4097        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4098                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4099                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4100                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4101        }
4102        if (p->score) {
4103                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4104                        inter_name_termination);
4105        } else {
4106                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4107        }
4108
4109        if (p->status == DIFF_STATUS_COPIED ||
4110            p->status == DIFF_STATUS_RENAMED) {
4111                const char *name_a, *name_b;
4112                name_a = p->one->path;
4113                name_b = p->two->path;
4114                strip_prefix(opt->prefix_length, &name_a, &name_b);
4115                write_name_quoted(name_a, opt->file, inter_name_termination);
4116                write_name_quoted(name_b, opt->file, line_termination);
4117        } else {
4118                const char *name_a, *name_b;
4119                name_a = p->one->mode ? p->one->path : p->two->path;
4120                name_b = NULL;
4121                strip_prefix(opt->prefix_length, &name_a, &name_b);
4122                write_name_quoted(name_a, opt->file, line_termination);
4123        }
4124}
4125
4126int diff_unmodified_pair(struct diff_filepair *p)
4127{
4128        /* This function is written stricter than necessary to support
4129         * the currently implemented transformers, but the idea is to
4130         * let transformers to produce diff_filepairs any way they want,
4131         * and filter and clean them up here before producing the output.
4132         */
4133        struct diff_filespec *one = p->one, *two = p->two;
4134
4135        if (DIFF_PAIR_UNMERGED(p))
4136                return 0; /* unmerged is interesting */
4137
4138        /* deletion, addition, mode or type change
4139         * and rename are all interesting.
4140         */
4141        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4142            DIFF_PAIR_MODE_CHANGED(p) ||
4143            strcmp(one->path, two->path))
4144                return 0;
4145
4146        /* both are valid and point at the same path.  that is, we are
4147         * dealing with a change.
4148         */
4149        if (one->sha1_valid && two->sha1_valid &&
4150            !hashcmp(one->sha1, two->sha1) &&
4151            !one->dirty_submodule && !two->dirty_submodule)
4152                return 1; /* no change */
4153        if (!one->sha1_valid && !two->sha1_valid)
4154                return 1; /* both look at the same file on the filesystem. */
4155        return 0;
4156}
4157
4158static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4159{
4160        if (diff_unmodified_pair(p))
4161                return;
4162
4163        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4164            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4165                return; /* no tree diffs in patch format */
4166
4167        run_diff(p, o);
4168}
4169
4170static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4171                            struct diffstat_t *diffstat)
4172{
4173        if (diff_unmodified_pair(p))
4174                return;
4175
4176        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4177            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4178                return; /* no useful stat for tree diffs */
4179
4180        run_diffstat(p, o, diffstat);
4181}
4182
4183static void diff_flush_checkdiff(struct diff_filepair *p,
4184                struct diff_options *o)
4185{
4186        if (diff_unmodified_pair(p))
4187                return;
4188
4189        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4190            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4191                return; /* nothing to check in tree diffs */
4192
4193        run_checkdiff(p, o);
4194}
4195
4196int diff_queue_is_empty(void)
4197{
4198        struct diff_queue_struct *q = &diff_queued_diff;
4199        int i;
4200        for (i = 0; i < q->nr; i++)
4201                if (!diff_unmodified_pair(q->queue[i]))
4202                        return 0;
4203        return 1;
4204}
4205
4206#if DIFF_DEBUG
4207void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4208{
4209        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4210                x, one ? one : "",
4211                s->path,
4212                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4213                s->mode,
4214                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4215        fprintf(stderr, "queue[%d] %s size %lu\n",
4216                x, one ? one : "",
4217                s->size);
4218}
4219
4220void diff_debug_filepair(const struct diff_filepair *p, int i)
4221{
4222        diff_debug_filespec(p->one, i, "one");
4223        diff_debug_filespec(p->two, i, "two");
4224        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4225                p->score, p->status ? p->status : '?',
4226                p->one->rename_used, p->broken_pair);
4227}
4228
4229void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4230{
4231        int i;
4232        if (msg)
4233                fprintf(stderr, "%s\n", msg);
4234        fprintf(stderr, "q->nr = %d\n", q->nr);
4235        for (i = 0; i < q->nr; i++) {
4236                struct diff_filepair *p = q->queue[i];
4237                diff_debug_filepair(p, i);
4238        }
4239}
4240#endif
4241
4242static void diff_resolve_rename_copy(void)
4243{
4244        int i;
4245        struct diff_filepair *p;
4246        struct diff_queue_struct *q = &diff_queued_diff;
4247
4248        diff_debug_queue("resolve-rename-copy", q);
4249
4250        for (i = 0; i < q->nr; i++) {
4251                p = q->queue[i];
4252                p->status = 0; /* undecided */
4253                if (DIFF_PAIR_UNMERGED(p))
4254                        p->status = DIFF_STATUS_UNMERGED;
4255                else if (!DIFF_FILE_VALID(p->one))
4256                        p->status = DIFF_STATUS_ADDED;
4257                else if (!DIFF_FILE_VALID(p->two))
4258                        p->status = DIFF_STATUS_DELETED;
4259                else if (DIFF_PAIR_TYPE_CHANGED(p))
4260                        p->status = DIFF_STATUS_TYPE_CHANGED;
4261
4262                /* from this point on, we are dealing with a pair
4263                 * whose both sides are valid and of the same type, i.e.
4264                 * either in-place edit or rename/copy edit.
4265                 */
4266                else if (DIFF_PAIR_RENAME(p)) {
4267                        /*
4268                         * A rename might have re-connected a broken
4269                         * pair up, causing the pathnames to be the
4270                         * same again. If so, that's not a rename at
4271                         * all, just a modification..
4272                         *
4273                         * Otherwise, see if this source was used for
4274                         * multiple renames, in which case we decrement
4275                         * the count, and call it a copy.
4276                         */
4277                        if (!strcmp(p->one->path, p->two->path))
4278                                p->status = DIFF_STATUS_MODIFIED;
4279                        else if (--p->one->rename_used > 0)
4280                                p->status = DIFF_STATUS_COPIED;
4281                        else
4282                                p->status = DIFF_STATUS_RENAMED;
4283                }
4284                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4285                         p->one->mode != p->two->mode ||
4286                         p->one->dirty_submodule ||
4287                         p->two->dirty_submodule ||
4288                         is_null_sha1(p->one->sha1))
4289                        p->status = DIFF_STATUS_MODIFIED;
4290                else {
4291                        /* This is a "no-change" entry and should not
4292                         * happen anymore, but prepare for broken callers.
4293                         */
4294                        error("feeding unmodified %s to diffcore",
4295                              p->one->path);
4296                        p->status = DIFF_STATUS_UNKNOWN;
4297                }
4298        }
4299        diff_debug_queue("resolve-rename-copy done", q);
4300}
4301
4302static int check_pair_status(struct diff_filepair *p)
4303{
4304        switch (p->status) {
4305        case DIFF_STATUS_UNKNOWN:
4306                return 0;
4307        case 0:
4308                die("internal error in diff-resolve-rename-copy");
4309        default:
4310                return 1;
4311        }
4312}
4313
4314static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4315{
4316        int fmt = opt->output_format;
4317
4318        if (fmt & DIFF_FORMAT_CHECKDIFF)
4319                diff_flush_checkdiff(p, opt);
4320        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4321                diff_flush_raw(p, opt);
4322        else if (fmt & DIFF_FORMAT_NAME) {
4323                const char *name_a, *name_b;
4324                name_a = p->two->path;
4325                name_b = NULL;
4326                strip_prefix(opt->prefix_length, &name_a, &name_b);
4327                write_name_quoted(name_a, opt->file, opt->line_termination);
4328        }
4329}
4330
4331static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4332{
4333        if (fs->mode)
4334                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4335        else
4336                fprintf(file, " %s ", newdelete);
4337        write_name_quoted(fs->path, file, '\n');
4338}
4339
4340
4341static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4342                const char *line_prefix)
4343{
4344        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4345                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4346                        p->two->mode, show_name ? ' ' : '\n');
4347                if (show_name) {
4348                        write_name_quoted(p->two->path, file, '\n');
4349                }
4350        }
4351}
4352
4353static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4354                        const char *line_prefix)
4355{
4356        char *names = pprint_rename(p->one->path, p->two->path);
4357
4358        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4359        free(names);
4360        show_mode_change(file, p, 0, line_prefix);
4361}
4362
4363static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4364{
4365        FILE *file = opt->file;
4366        const char *line_prefix = diff_line_prefix(opt);
4367
4368        switch(p->status) {
4369        case DIFF_STATUS_DELETED:
4370                fputs(line_prefix, file);
4371                show_file_mode_name(file, "delete", p->one);
4372                break;
4373        case DIFF_STATUS_ADDED:
4374                fputs(line_prefix, file);
4375                show_file_mode_name(file, "create", p->two);
4376                break;
4377        case DIFF_STATUS_COPIED:
4378                fputs(line_prefix, file);
4379                show_rename_copy(file, "copy", p, line_prefix);
4380                break;
4381        case DIFF_STATUS_RENAMED:
4382                fputs(line_prefix, file);
4383                show_rename_copy(file, "rename", p, line_prefix);
4384                break;
4385        default:
4386                if (p->score) {
4387                        fprintf(file, "%s rewrite ", line_prefix);
4388                        write_name_quoted(p->two->path, file, ' ');
4389                        fprintf(file, "(%d%%)\n", similarity_index(p));
4390                }
4391                show_mode_change(file, p, !p->score, line_prefix);
4392                break;
4393        }
4394}
4395
4396struct patch_id_t {
4397        git_SHA_CTX *ctx;
4398        int patchlen;
4399};
4400
4401static int remove_space(char *line, int len)
4402{
4403        int i;
4404        char *dst = line;
4405        unsigned char c;
4406
4407        for (i = 0; i < len; i++)
4408                if (!isspace((c = line[i])))
4409                        *dst++ = c;
4410
4411        return dst - line;
4412}
4413
4414static void patch_id_consume(void *priv, char *line, unsigned long len)
4415{
4416        struct patch_id_t *data = priv;
4417        int new_len;
4418
4419        /* Ignore line numbers when computing the SHA1 of the patch */
4420        if (starts_with(line, "@@ -"))
4421                return;
4422
4423        new_len = remove_space(line, len);
4424
4425        git_SHA1_Update(data->ctx, line, new_len);
4426        data->patchlen += new_len;
4427}
4428
4429/* returns 0 upon success, and writes result into sha1 */
4430static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4431{
4432        struct diff_queue_struct *q = &diff_queued_diff;
4433        int i;
4434        git_SHA_CTX ctx;
4435        struct patch_id_t data;
4436        char buffer[PATH_MAX * 4 + 20];
4437
4438        git_SHA1_Init(&ctx);
4439        memset(&data, 0, sizeof(struct patch_id_t));
4440        data.ctx = &ctx;
4441
4442        for (i = 0; i < q->nr; i++) {
4443                xpparam_t xpp;
4444                xdemitconf_t xecfg;
4445                mmfile_t mf1, mf2;
4446                struct diff_filepair *p = q->queue[i];
4447                int len1, len2;
4448
4449                memset(&xpp, 0, sizeof(xpp));
4450                memset(&xecfg, 0, sizeof(xecfg));
4451                if (p->status == 0)
4452                        return error("internal diff status error");
4453                if (p->status == DIFF_STATUS_UNKNOWN)
4454                        continue;
4455                if (diff_unmodified_pair(p))
4456                        continue;
4457                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4458                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4459                        continue;
4460                if (DIFF_PAIR_UNMERGED(p))
4461                        continue;
4462
4463                diff_fill_sha1_info(p->one);
4464                diff_fill_sha1_info(p->two);
4465                if (fill_mmfile(&mf1, p->one) < 0 ||
4466                                fill_mmfile(&mf2, p->two) < 0)
4467                        return error("unable to read files to diff");
4468
4469                len1 = remove_space(p->one->path, strlen(p->one->path));
4470                len2 = remove_space(p->two->path, strlen(p->two->path));
4471                if (p->one->mode == 0)
4472                        len1 = snprintf(buffer, sizeof(buffer),
4473                                        "diff--gita/%.*sb/%.*s"
4474                                        "newfilemode%06o"
4475                                        "---/dev/null"
4476                                        "+++b/%.*s",
4477                                        len1, p->one->path,
4478                                        len2, p->two->path,
4479                                        p->two->mode,
4480                                        len2, p->two->path);
4481                else if (p->two->mode == 0)
4482                        len1 = snprintf(buffer, sizeof(buffer),
4483                                        "diff--gita/%.*sb/%.*s"
4484                                        "deletedfilemode%06o"
4485                                        "---a/%.*s"
4486                                        "+++/dev/null",
4487                                        len1, p->one->path,
4488                                        len2, p->two->path,
4489                                        p->one->mode,
4490                                        len1, p->one->path);
4491                else
4492                        len1 = snprintf(buffer, sizeof(buffer),
4493                                        "diff--gita/%.*sb/%.*s"
4494                                        "---a/%.*s"
4495                                        "+++b/%.*s",
4496                                        len1, p->one->path,
4497                                        len2, p->two->path,
4498                                        len1, p->one->path,
4499                                        len2, p->two->path);
4500                git_SHA1_Update(&ctx, buffer, len1);
4501
4502                if (diff_filespec_is_binary(p->one) ||
4503                    diff_filespec_is_binary(p->two)) {
4504                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4505                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4506                        continue;
4507                }
4508
4509                xpp.flags = 0;
4510                xecfg.ctxlen = 3;
4511                xecfg.flags = 0;
4512                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4513                              &xpp, &xecfg);
4514        }
4515
4516        git_SHA1_Final(sha1, &ctx);
4517        return 0;
4518}
4519
4520int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4521{
4522        struct diff_queue_struct *q = &diff_queued_diff;
4523        int i;
4524        int result = diff_get_patch_id(options, sha1);
4525
4526        for (i = 0; i < q->nr; i++)
4527                diff_free_filepair(q->queue[i]);
4528
4529        free(q->queue);
4530        DIFF_QUEUE_CLEAR(q);
4531
4532        return result;
4533}
4534
4535static int is_summary_empty(const struct diff_queue_struct *q)
4536{
4537        int i;
4538
4539        for (i = 0; i < q->nr; i++) {
4540                const struct diff_filepair *p = q->queue[i];
4541
4542                switch (p->status) {
4543                case DIFF_STATUS_DELETED:
4544                case DIFF_STATUS_ADDED:
4545                case DIFF_STATUS_COPIED:
4546                case DIFF_STATUS_RENAMED:
4547                        return 0;
4548                default:
4549                        if (p->score)
4550                                return 0;
4551                        if (p->one->mode && p->two->mode &&
4552                            p->one->mode != p->two->mode)
4553                                return 0;
4554                        break;
4555                }
4556        }
4557        return 1;
4558}
4559
4560static const char rename_limit_warning[] =
4561"inexact rename detection was skipped due to too many files.";
4562
4563static const char degrade_cc_to_c_warning[] =
4564"only found copies from modified paths due to too many files.";
4565
4566static const char rename_limit_advice[] =
4567"you may want to set your %s variable to at least "
4568"%d and retry the command.";
4569
4570void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4571{
4572        if (degraded_cc)
4573                warning(degrade_cc_to_c_warning);
4574        else if (needed)
4575                warning(rename_limit_warning);
4576        else
4577                return;
4578        if (0 < needed && needed < 32767)
4579                warning(rename_limit_advice, varname, needed);
4580}
4581
4582void diff_flush(struct diff_options *options)
4583{
4584        struct diff_queue_struct *q = &diff_queued_diff;
4585        int i, output_format = options->output_format;
4586        int separator = 0;
4587        int dirstat_by_line = 0;
4588
4589        /*
4590         * Order: raw, stat, summary, patch
4591         * or:    name/name-status/checkdiff (other bits clear)
4592         */
4593        if (!q->nr)
4594                goto free_queue;
4595
4596        if (output_format & (DIFF_FORMAT_RAW |
4597                             DIFF_FORMAT_NAME |
4598                             DIFF_FORMAT_NAME_STATUS |
4599                             DIFF_FORMAT_CHECKDIFF)) {
4600                for (i = 0; i < q->nr; i++) {
4601                        struct diff_filepair *p = q->queue[i];
4602                        if (check_pair_status(p))
4603                                flush_one_pair(p, options);
4604                }
4605                separator++;
4606        }
4607
4608        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4609                dirstat_by_line = 1;
4610
4611        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4612            dirstat_by_line) {
4613                struct diffstat_t diffstat;
4614
4615                memset(&diffstat, 0, sizeof(struct diffstat_t));
4616                for (i = 0; i < q->nr; i++) {
4617                        struct diff_filepair *p = q->queue[i];
4618                        if (check_pair_status(p))
4619                                diff_flush_stat(p, options, &diffstat);
4620                }
4621                if (output_format & DIFF_FORMAT_NUMSTAT)
4622                        show_numstat(&diffstat, options);
4623                if (output_format & DIFF_FORMAT_DIFFSTAT)
4624                        show_stats(&diffstat, options);
4625                if (output_format & DIFF_FORMAT_SHORTSTAT)
4626                        show_shortstats(&diffstat, options);
4627                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4628                        show_dirstat_by_line(&diffstat, options);
4629                free_diffstat_info(&diffstat);
4630                separator++;
4631        }
4632        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4633                show_dirstat(options);
4634
4635        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4636                for (i = 0; i < q->nr; i++) {
4637                        diff_summary(options, q->queue[i]);
4638                }
4639                separator++;
4640        }
4641
4642        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4643            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4644            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4645                /*
4646                 * run diff_flush_patch for the exit status. setting
4647                 * options->file to /dev/null should be safe, because we
4648                 * aren't supposed to produce any output anyway.
4649                 */
4650                if (options->close_file)
4651                        fclose(options->file);
4652                options->file = fopen("/dev/null", "w");
4653                if (!options->file)
4654                        die_errno("Could not open /dev/null");
4655                options->close_file = 1;
4656                for (i = 0; i < q->nr; i++) {
4657                        struct diff_filepair *p = q->queue[i];
4658                        if (check_pair_status(p))
4659                                diff_flush_patch(p, options);
4660                        if (options->found_changes)
4661                                break;
4662                }
4663        }
4664
4665        if (output_format & DIFF_FORMAT_PATCH) {
4666                if (separator) {
4667                        fprintf(options->file, "%s%c",
4668                                diff_line_prefix(options),
4669                                options->line_termination);
4670                        if (options->stat_sep) {
4671                                /* attach patch instead of inline */
4672                                fputs(options->stat_sep, options->file);
4673                        }
4674                }
4675
4676                for (i = 0; i < q->nr; i++) {
4677                        struct diff_filepair *p = q->queue[i];
4678                        if (check_pair_status(p))
4679                                diff_flush_patch(p, options);
4680                }
4681        }
4682
4683        if (output_format & DIFF_FORMAT_CALLBACK)
4684                options->format_callback(q, options, options->format_callback_data);
4685
4686        for (i = 0; i < q->nr; i++)
4687                diff_free_filepair(q->queue[i]);
4688free_queue:
4689        free(q->queue);
4690        DIFF_QUEUE_CLEAR(q);
4691        if (options->close_file)
4692                fclose(options->file);
4693
4694        /*
4695         * Report the content-level differences with HAS_CHANGES;
4696         * diff_addremove/diff_change does not set the bit when
4697         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4698         */
4699        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4700                if (options->found_changes)
4701                        DIFF_OPT_SET(options, HAS_CHANGES);
4702                else
4703                        DIFF_OPT_CLR(options, HAS_CHANGES);
4704        }
4705}
4706
4707static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4708{
4709        return (((p->status == DIFF_STATUS_MODIFIED) &&
4710                 ((p->score &&
4711                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4712                  (!p->score &&
4713                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4714                ((p->status != DIFF_STATUS_MODIFIED) &&
4715                 filter_bit_tst(p->status, options)));
4716}
4717
4718static void diffcore_apply_filter(struct diff_options *options)
4719{
4720        int i;
4721        struct diff_queue_struct *q = &diff_queued_diff;
4722        struct diff_queue_struct outq;
4723
4724        DIFF_QUEUE_CLEAR(&outq);
4725
4726        if (!options->filter)
4727                return;
4728
4729        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4730                int found;
4731                for (i = found = 0; !found && i < q->nr; i++) {
4732                        if (match_filter(options, q->queue[i]))
4733                                found++;
4734                }
4735                if (found)
4736                        return;
4737
4738                /* otherwise we will clear the whole queue
4739                 * by copying the empty outq at the end of this
4740                 * function, but first clear the current entries
4741                 * in the queue.
4742                 */
4743                for (i = 0; i < q->nr; i++)
4744                        diff_free_filepair(q->queue[i]);
4745        }
4746        else {
4747                /* Only the matching ones */
4748                for (i = 0; i < q->nr; i++) {
4749                        struct diff_filepair *p = q->queue[i];
4750                        if (match_filter(options, p))
4751                                diff_q(&outq, p);
4752                        else
4753                                diff_free_filepair(p);
4754                }
4755        }
4756        free(q->queue);
4757        *q = outq;
4758}
4759
4760/* Check whether two filespecs with the same mode and size are identical */
4761static int diff_filespec_is_identical(struct diff_filespec *one,
4762                                      struct diff_filespec *two)
4763{
4764        if (S_ISGITLINK(one->mode))
4765                return 0;
4766        if (diff_populate_filespec(one, 0))
4767                return 0;
4768        if (diff_populate_filespec(two, 0))
4769                return 0;
4770        return !memcmp(one->data, two->data, one->size);
4771}
4772
4773static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4774{
4775        if (p->done_skip_stat_unmatch)
4776                return p->skip_stat_unmatch_result;
4777
4778        p->done_skip_stat_unmatch = 1;
4779        p->skip_stat_unmatch_result = 0;
4780        /*
4781         * 1. Entries that come from stat info dirtiness
4782         *    always have both sides (iow, not create/delete),
4783         *    one side of the object name is unknown, with
4784         *    the same mode and size.  Keep the ones that
4785         *    do not match these criteria.  They have real
4786         *    differences.
4787         *
4788         * 2. At this point, the file is known to be modified,
4789         *    with the same mode and size, and the object
4790         *    name of one side is unknown.  Need to inspect
4791         *    the identical contents.
4792         */
4793        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4794            !DIFF_FILE_VALID(p->two) ||
4795            (p->one->sha1_valid && p->two->sha1_valid) ||
4796            (p->one->mode != p->two->mode) ||
4797            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4798            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4799            (p->one->size != p->two->size) ||
4800            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4801                p->skip_stat_unmatch_result = 1;
4802        return p->skip_stat_unmatch_result;
4803}
4804
4805static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4806{
4807        int i;
4808        struct diff_queue_struct *q = &diff_queued_diff;
4809        struct diff_queue_struct outq;
4810        DIFF_QUEUE_CLEAR(&outq);
4811
4812        for (i = 0; i < q->nr; i++) {
4813                struct diff_filepair *p = q->queue[i];
4814
4815                if (diff_filespec_check_stat_unmatch(p))
4816                        diff_q(&outq, p);
4817                else {
4818                        /*
4819                         * The caller can subtract 1 from skip_stat_unmatch
4820                         * to determine how many paths were dirty only
4821                         * due to stat info mismatch.
4822                         */
4823                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4824                                diffopt->skip_stat_unmatch++;
4825                        diff_free_filepair(p);
4826                }
4827        }
4828        free(q->queue);
4829        *q = outq;
4830}
4831
4832static int diffnamecmp(const void *a_, const void *b_)
4833{
4834        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4835        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4836        const char *name_a, *name_b;
4837
4838        name_a = a->one ? a->one->path : a->two->path;
4839        name_b = b->one ? b->one->path : b->two->path;
4840        return strcmp(name_a, name_b);
4841}
4842
4843void diffcore_fix_diff_index(struct diff_options *options)
4844{
4845        struct diff_queue_struct *q = &diff_queued_diff;
4846        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4847}
4848
4849void diffcore_std(struct diff_options *options)
4850{
4851        /* NOTE please keep the following in sync with diff_tree_combined() */
4852        if (options->skip_stat_unmatch)
4853                diffcore_skip_stat_unmatch(options);
4854        if (!options->found_follow) {
4855                /* See try_to_follow_renames() in tree-diff.c */
4856                if (options->break_opt != -1)
4857                        diffcore_break(options->break_opt);
4858                if (options->detect_rename)
4859                        diffcore_rename(options);
4860                if (options->break_opt != -1)
4861                        diffcore_merge_broken();
4862        }
4863        if (options->pickaxe)
4864                diffcore_pickaxe(options);
4865        if (options->orderfile)
4866                diffcore_order(options->orderfile);
4867        if (!options->found_follow)
4868                /* See try_to_follow_renames() in tree-diff.c */
4869                diff_resolve_rename_copy();
4870        diffcore_apply_filter(options);
4871
4872        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4873                DIFF_OPT_SET(options, HAS_CHANGES);
4874        else
4875                DIFF_OPT_CLR(options, HAS_CHANGES);
4876
4877        options->found_follow = 0;
4878}
4879
4880int diff_result_code(struct diff_options *opt, int status)
4881{
4882        int result = 0;
4883
4884        diff_warn_rename_limit("diff.renameLimit",
4885                               opt->needed_rename_limit,
4886                               opt->degraded_cc_to_c);
4887        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4888            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4889                return status;
4890        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4891            DIFF_OPT_TST(opt, HAS_CHANGES))
4892                result |= 01;
4893        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4894            DIFF_OPT_TST(opt, CHECK_FAILED))
4895                result |= 02;
4896        return result;
4897}
4898
4899int diff_can_quit_early(struct diff_options *opt)
4900{
4901        return (DIFF_OPT_TST(opt, QUICK) &&
4902                !opt->filter &&
4903                DIFF_OPT_TST(opt, HAS_CHANGES));
4904}
4905
4906/*
4907 * Shall changes to this submodule be ignored?
4908 *
4909 * Submodule changes can be configured to be ignored separately for each path,
4910 * but that configuration can be overridden from the command line.
4911 */
4912static int is_submodule_ignored(const char *path, struct diff_options *options)
4913{
4914        int ignored = 0;
4915        unsigned orig_flags = options->flags;
4916        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4917                set_diffopt_flags_from_submodule_config(options, path);
4918        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4919                ignored = 1;
4920        options->flags = orig_flags;
4921        return ignored;
4922}
4923
4924void diff_addremove(struct diff_options *options,
4925                    int addremove, unsigned mode,
4926                    const unsigned char *sha1,
4927                    int sha1_valid,
4928                    const char *concatpath, unsigned dirty_submodule)
4929{
4930        struct diff_filespec *one, *two;
4931
4932        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4933                return;
4934
4935        /* This may look odd, but it is a preparation for
4936         * feeding "there are unchanged files which should
4937         * not produce diffs, but when you are doing copy
4938         * detection you would need them, so here they are"
4939         * entries to the diff-core.  They will be prefixed
4940         * with something like '=' or '*' (I haven't decided
4941         * which but should not make any difference).
4942         * Feeding the same new and old to diff_change()
4943         * also has the same effect.
4944         * Before the final output happens, they are pruned after
4945         * merged into rename/copy pairs as appropriate.
4946         */
4947        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4948                addremove = (addremove == '+' ? '-' :
4949                             addremove == '-' ? '+' : addremove);
4950
4951        if (options->prefix &&
4952            strncmp(concatpath, options->prefix, options->prefix_length))
4953                return;
4954
4955        one = alloc_filespec(concatpath);
4956        two = alloc_filespec(concatpath);
4957
4958        if (addremove != '+')
4959                fill_filespec(one, sha1, sha1_valid, mode);
4960        if (addremove != '-') {
4961                fill_filespec(two, sha1, sha1_valid, mode);
4962                two->dirty_submodule = dirty_submodule;
4963        }
4964
4965        diff_queue(&diff_queued_diff, one, two);
4966        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4967                DIFF_OPT_SET(options, HAS_CHANGES);
4968}
4969
4970void diff_change(struct diff_options *options,
4971                 unsigned old_mode, unsigned new_mode,
4972                 const unsigned char *old_sha1,
4973                 const unsigned char *new_sha1,
4974                 int old_sha1_valid, int new_sha1_valid,
4975                 const char *concatpath,
4976                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4977{
4978        struct diff_filespec *one, *two;
4979        struct diff_filepair *p;
4980
4981        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4982            is_submodule_ignored(concatpath, options))
4983                return;
4984
4985        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4986                unsigned tmp;
4987                const unsigned char *tmp_c;
4988                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4989                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4990                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4991                        new_sha1_valid = tmp;
4992                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4993                        new_dirty_submodule = tmp;
4994        }
4995
4996        if (options->prefix &&
4997            strncmp(concatpath, options->prefix, options->prefix_length))
4998                return;
4999
5000        one = alloc_filespec(concatpath);
5001        two = alloc_filespec(concatpath);
5002        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5003        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5004        one->dirty_submodule = old_dirty_submodule;
5005        two->dirty_submodule = new_dirty_submodule;
5006        p = diff_queue(&diff_queued_diff, one, two);
5007
5008        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5009                return;
5010
5011        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5012            !diff_filespec_check_stat_unmatch(p))
5013                return;
5014
5015        DIFF_OPT_SET(options, HAS_CHANGES);
5016}
5017
5018struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5019{
5020        struct diff_filepair *pair;
5021        struct diff_filespec *one, *two;
5022
5023        if (options->prefix &&
5024            strncmp(path, options->prefix, options->prefix_length))
5025                return NULL;
5026
5027        one = alloc_filespec(path);
5028        two = alloc_filespec(path);
5029        pair = diff_queue(&diff_queued_diff, one, two);
5030        pair->is_unmerged = 1;
5031        return pair;
5032}
5033
5034static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5035                size_t *outsize)
5036{
5037        struct diff_tempfile *temp;
5038        const char *argv[3];
5039        const char **arg = argv;
5040        struct child_process child = CHILD_PROCESS_INIT;
5041        struct strbuf buf = STRBUF_INIT;
5042        int err = 0;
5043
5044        temp = prepare_temp_file(spec->path, spec);
5045        *arg++ = pgm;
5046        *arg++ = temp->name;
5047        *arg = NULL;
5048
5049        child.use_shell = 1;
5050        child.argv = argv;
5051        child.out = -1;
5052        if (start_command(&child)) {
5053                remove_tempfile();
5054                return NULL;
5055        }
5056
5057        if (strbuf_read(&buf, child.out, 0) < 0)
5058                err = error("error reading from textconv command '%s'", pgm);
5059        close(child.out);
5060
5061        if (finish_command(&child) || err) {
5062                strbuf_release(&buf);
5063                remove_tempfile();
5064                return NULL;
5065        }
5066        remove_tempfile();
5067
5068        return strbuf_detach(&buf, outsize);
5069}
5070
5071size_t fill_textconv(struct userdiff_driver *driver,
5072                     struct diff_filespec *df,
5073                     char **outbuf)
5074{
5075        size_t size;
5076
5077        if (!driver || !driver->textconv) {
5078                if (!DIFF_FILE_VALID(df)) {
5079                        *outbuf = "";
5080                        return 0;
5081                }
5082                if (diff_populate_filespec(df, 0))
5083                        die("unable to read files to diff");
5084                *outbuf = df->data;
5085                return df->size;
5086        }
5087
5088        if (driver->textconv_cache && df->sha1_valid) {
5089                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5090                                          &size);
5091                if (*outbuf)
5092                        return size;
5093        }
5094
5095        *outbuf = run_textconv(driver->textconv, df, &size);
5096        if (!*outbuf)
5097                die("unable to read files to diff");
5098
5099        if (driver->textconv_cache && df->sha1_valid) {
5100                /* ignore errors, as we might be in a readonly repository */
5101                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5102                                size);
5103                /*
5104                 * we could save up changes and flush them all at the end,
5105                 * but we would need an extra call after all diffing is done.
5106                 * Since generating a cache entry is the slow path anyway,
5107                 * this extra overhead probably isn't a big deal.
5108                 */
5109                notes_cache_write(driver->textconv_cache);
5110        }
5111
5112        return size;
5113}
5114
5115void setup_diff_pager(struct diff_options *opt)
5116{
5117        /*
5118         * If the user asked for our exit code, then either they want --quiet
5119         * or --exit-code. We should definitely not bother with a pager in the
5120         * former case, as we will generate no output. Since we still properly
5121         * report our exit code even when a pager is run, we _could_ run a
5122         * pager with --exit-code. But since we have not done so historically,
5123         * and because it is easy to find people oneline advising "git diff
5124         * --exit-code" in hooks and other scripts, we do not do so.
5125         */
5126        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5127            check_pager_config("diff") != 0)
5128                setup_pager();
5129}