diff.con commit diff-tree: update stale in-code comments (8ba74bf)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18#include "string-list.h"
  19#include "argv-array.h"
  20
  21#ifdef NO_FAST_WORKING_DIRECTORY
  22#define FAST_WORKING_DIRECTORY 0
  23#else
  24#define FAST_WORKING_DIRECTORY 1
  25#endif
  26
  27static int diff_detect_rename_default;
  28static int diff_rename_limit_default = 400;
  29static int diff_suppress_blank_empty;
  30static int diff_use_color_default = -1;
  31static int diff_context_default = 3;
  32static const char *diff_word_regex_cfg;
  33static const char *external_diff_cmd_cfg;
  34static const char *diff_order_file_cfg;
  35int diff_auto_refresh_index = 1;
  36static int diff_mnemonic_prefix;
  37static int diff_no_prefix;
  38static int diff_stat_graph_width;
  39static int diff_dirstat_permille_default = 30;
  40static struct diff_options default_diff_options;
  41static long diff_algorithm;
  42
  43static char diff_colors[][COLOR_MAXLEN] = {
  44        GIT_COLOR_RESET,
  45        GIT_COLOR_NORMAL,       /* CONTEXT */
  46        GIT_COLOR_BOLD,         /* METAINFO */
  47        GIT_COLOR_CYAN,         /* FRAGINFO */
  48        GIT_COLOR_RED,          /* OLD */
  49        GIT_COLOR_GREEN,        /* NEW */
  50        GIT_COLOR_YELLOW,       /* COMMIT */
  51        GIT_COLOR_BG_RED,       /* WHITESPACE */
  52        GIT_COLOR_NORMAL,       /* FUNCINFO */
  53};
  54
  55static int parse_diff_color_slot(const char *var)
  56{
  57        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  58                return DIFF_CONTEXT;
  59        if (!strcasecmp(var, "meta"))
  60                return DIFF_METAINFO;
  61        if (!strcasecmp(var, "frag"))
  62                return DIFF_FRAGINFO;
  63        if (!strcasecmp(var, "old"))
  64                return DIFF_FILE_OLD;
  65        if (!strcasecmp(var, "new"))
  66                return DIFF_FILE_NEW;
  67        if (!strcasecmp(var, "commit"))
  68                return DIFF_COMMIT;
  69        if (!strcasecmp(var, "whitespace"))
  70                return DIFF_WHITESPACE;
  71        if (!strcasecmp(var, "func"))
  72                return DIFF_FUNCINFO;
  73        return -1;
  74}
  75
  76static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  77                                struct strbuf *errmsg)
  78{
  79        char *params_copy = xstrdup(params_string);
  80        struct string_list params = STRING_LIST_INIT_NODUP;
  81        int ret = 0;
  82        int i;
  83
  84        if (*params_copy)
  85                string_list_split_in_place(&params, params_copy, ',', -1);
  86        for (i = 0; i < params.nr; i++) {
  87                const char *p = params.items[i].string;
  88                if (!strcmp(p, "changes")) {
  89                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  90                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  91                } else if (!strcmp(p, "lines")) {
  92                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  93                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  94                } else if (!strcmp(p, "files")) {
  95                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  96                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  97                } else if (!strcmp(p, "noncumulative")) {
  98                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  99                } else if (!strcmp(p, "cumulative")) {
 100                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 101                } else if (isdigit(*p)) {
 102                        char *end;
 103                        int permille = strtoul(p, &end, 10) * 10;
 104                        if (*end == '.' && isdigit(*++end)) {
 105                                /* only use first digit */
 106                                permille += *end - '0';
 107                                /* .. and ignore any further digits */
 108                                while (isdigit(*++end))
 109                                        ; /* nothing */
 110                        }
 111                        if (!*end)
 112                                options->dirstat_permille = permille;
 113                        else {
 114                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 115                                            p);
 116                                ret++;
 117                        }
 118                } else {
 119                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 120                        ret++;
 121                }
 122
 123        }
 124        string_list_clear(&params, 0);
 125        free(params_copy);
 126        return ret;
 127}
 128
 129static int parse_submodule_params(struct diff_options *options, const char *value)
 130{
 131        if (!strcmp(value, "log"))
 132                DIFF_OPT_SET(options, SUBMODULE_LOG);
 133        else if (!strcmp(value, "short"))
 134                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 135        else
 136                return -1;
 137        return 0;
 138}
 139
 140static int git_config_rename(const char *var, const char *value)
 141{
 142        if (!value)
 143                return DIFF_DETECT_RENAME;
 144        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 145                return  DIFF_DETECT_COPY;
 146        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 147}
 148
 149long parse_algorithm_value(const char *value)
 150{
 151        if (!value)
 152                return -1;
 153        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 154                return 0;
 155        else if (!strcasecmp(value, "minimal"))
 156                return XDF_NEED_MINIMAL;
 157        else if (!strcasecmp(value, "patience"))
 158                return XDF_PATIENCE_DIFF;
 159        else if (!strcasecmp(value, "histogram"))
 160                return XDF_HISTOGRAM_DIFF;
 161        return -1;
 162}
 163
 164/*
 165 * These are to give UI layer defaults.
 166 * The core-level commands such as git-diff-files should
 167 * never be affected by the setting of diff.renames
 168 * the user happens to have in the configuration file.
 169 */
 170int git_diff_ui_config(const char *var, const char *value, void *cb)
 171{
 172        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 173                diff_use_color_default = git_config_colorbool(var, value);
 174                return 0;
 175        }
 176        if (!strcmp(var, "diff.context")) {
 177                diff_context_default = git_config_int(var, value);
 178                if (diff_context_default < 0)
 179                        return -1;
 180                return 0;
 181        }
 182        if (!strcmp(var, "diff.renames")) {
 183                diff_detect_rename_default = git_config_rename(var, value);
 184                return 0;
 185        }
 186        if (!strcmp(var, "diff.autorefreshindex")) {
 187                diff_auto_refresh_index = git_config_bool(var, value);
 188                return 0;
 189        }
 190        if (!strcmp(var, "diff.mnemonicprefix")) {
 191                diff_mnemonic_prefix = git_config_bool(var, value);
 192                return 0;
 193        }
 194        if (!strcmp(var, "diff.noprefix")) {
 195                diff_no_prefix = git_config_bool(var, value);
 196                return 0;
 197        }
 198        if (!strcmp(var, "diff.statgraphwidth")) {
 199                diff_stat_graph_width = git_config_int(var, value);
 200                return 0;
 201        }
 202        if (!strcmp(var, "diff.external"))
 203                return git_config_string(&external_diff_cmd_cfg, var, value);
 204        if (!strcmp(var, "diff.wordregex"))
 205                return git_config_string(&diff_word_regex_cfg, var, value);
 206        if (!strcmp(var, "diff.orderfile"))
 207                return git_config_pathname(&diff_order_file_cfg, var, value);
 208
 209        if (!strcmp(var, "diff.ignoresubmodules"))
 210                handle_ignore_submodules_arg(&default_diff_options, value);
 211
 212        if (!strcmp(var, "diff.submodule")) {
 213                if (parse_submodule_params(&default_diff_options, value))
 214                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 215                                value);
 216                return 0;
 217        }
 218
 219        if (!strcmp(var, "diff.algorithm")) {
 220                diff_algorithm = parse_algorithm_value(value);
 221                if (diff_algorithm < 0)
 222                        return -1;
 223                return 0;
 224        }
 225
 226        if (git_color_config(var, value, cb) < 0)
 227                return -1;
 228
 229        return git_diff_basic_config(var, value, cb);
 230}
 231
 232int git_diff_basic_config(const char *var, const char *value, void *cb)
 233{
 234        const char *name;
 235
 236        if (!strcmp(var, "diff.renamelimit")) {
 237                diff_rename_limit_default = git_config_int(var, value);
 238                return 0;
 239        }
 240
 241        if (userdiff_config(var, value) < 0)
 242                return -1;
 243
 244        if (skip_prefix(var, "diff.color.", &name) ||
 245            skip_prefix(var, "color.diff.", &name)) {
 246                int slot = parse_diff_color_slot(name);
 247                if (slot < 0)
 248                        return 0;
 249                if (!value)
 250                        return config_error_nonbool(var);
 251                return color_parse(value, diff_colors[slot]);
 252        }
 253
 254        /* like GNU diff's --suppress-blank-empty option  */
 255        if (!strcmp(var, "diff.suppressblankempty") ||
 256                        /* for backwards compatibility */
 257                        !strcmp(var, "diff.suppress-blank-empty")) {
 258                diff_suppress_blank_empty = git_config_bool(var, value);
 259                return 0;
 260        }
 261
 262        if (!strcmp(var, "diff.dirstat")) {
 263                struct strbuf errmsg = STRBUF_INIT;
 264                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 265                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 266                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 267                                errmsg.buf);
 268                strbuf_release(&errmsg);
 269                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 270                return 0;
 271        }
 272
 273        if (starts_with(var, "submodule."))
 274                return parse_submodule_config_option(var, value);
 275
 276        return git_default_config(var, value, cb);
 277}
 278
 279static char *quote_two(const char *one, const char *two)
 280{
 281        int need_one = quote_c_style(one, NULL, NULL, 1);
 282        int need_two = quote_c_style(two, NULL, NULL, 1);
 283        struct strbuf res = STRBUF_INIT;
 284
 285        if (need_one + need_two) {
 286                strbuf_addch(&res, '"');
 287                quote_c_style(one, &res, NULL, 1);
 288                quote_c_style(two, &res, NULL, 1);
 289                strbuf_addch(&res, '"');
 290        } else {
 291                strbuf_addstr(&res, one);
 292                strbuf_addstr(&res, two);
 293        }
 294        return strbuf_detach(&res, NULL);
 295}
 296
 297static const char *external_diff(void)
 298{
 299        static const char *external_diff_cmd = NULL;
 300        static int done_preparing = 0;
 301
 302        if (done_preparing)
 303                return external_diff_cmd;
 304        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 305        if (!external_diff_cmd)
 306                external_diff_cmd = external_diff_cmd_cfg;
 307        done_preparing = 1;
 308        return external_diff_cmd;
 309}
 310
 311static struct diff_tempfile {
 312        const char *name; /* filename external diff should read from */
 313        char hex[41];
 314        char mode[10];
 315        char tmp_path[PATH_MAX];
 316} diff_temp[2];
 317
 318typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 319
 320struct emit_callback {
 321        int color_diff;
 322        unsigned ws_rule;
 323        int blank_at_eof_in_preimage;
 324        int blank_at_eof_in_postimage;
 325        int lno_in_preimage;
 326        int lno_in_postimage;
 327        sane_truncate_fn truncate;
 328        const char **label_path;
 329        struct diff_words_data *diff_words;
 330        struct diff_options *opt;
 331        int *found_changesp;
 332        struct strbuf *header;
 333};
 334
 335static int count_lines(const char *data, int size)
 336{
 337        int count, ch, completely_empty = 1, nl_just_seen = 0;
 338        count = 0;
 339        while (0 < size--) {
 340                ch = *data++;
 341                if (ch == '\n') {
 342                        count++;
 343                        nl_just_seen = 1;
 344                        completely_empty = 0;
 345                }
 346                else {
 347                        nl_just_seen = 0;
 348                        completely_empty = 0;
 349                }
 350        }
 351        if (completely_empty)
 352                return 0;
 353        if (!nl_just_seen)
 354                count++; /* no trailing newline */
 355        return count;
 356}
 357
 358static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 359{
 360        if (!DIFF_FILE_VALID(one)) {
 361                mf->ptr = (char *)""; /* does not matter */
 362                mf->size = 0;
 363                return 0;
 364        }
 365        else if (diff_populate_filespec(one, 0))
 366                return -1;
 367
 368        mf->ptr = one->data;
 369        mf->size = one->size;
 370        return 0;
 371}
 372
 373/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 374static unsigned long diff_filespec_size(struct diff_filespec *one)
 375{
 376        if (!DIFF_FILE_VALID(one))
 377                return 0;
 378        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 379        return one->size;
 380}
 381
 382static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 383{
 384        char *ptr = mf->ptr;
 385        long size = mf->size;
 386        int cnt = 0;
 387
 388        if (!size)
 389                return cnt;
 390        ptr += size - 1; /* pointing at the very end */
 391        if (*ptr != '\n')
 392                ; /* incomplete line */
 393        else
 394                ptr--; /* skip the last LF */
 395        while (mf->ptr < ptr) {
 396                char *prev_eol;
 397                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 398                        if (*prev_eol == '\n')
 399                                break;
 400                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 401                        break;
 402                cnt++;
 403                ptr = prev_eol - 1;
 404        }
 405        return cnt;
 406}
 407
 408static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 409                               struct emit_callback *ecbdata)
 410{
 411        int l1, l2, at;
 412        unsigned ws_rule = ecbdata->ws_rule;
 413        l1 = count_trailing_blank(mf1, ws_rule);
 414        l2 = count_trailing_blank(mf2, ws_rule);
 415        if (l2 <= l1) {
 416                ecbdata->blank_at_eof_in_preimage = 0;
 417                ecbdata->blank_at_eof_in_postimage = 0;
 418                return;
 419        }
 420        at = count_lines(mf1->ptr, mf1->size);
 421        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 422
 423        at = count_lines(mf2->ptr, mf2->size);
 424        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 425}
 426
 427static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 428                        int first, const char *line, int len)
 429{
 430        int has_trailing_newline, has_trailing_carriage_return;
 431        int nofirst;
 432        FILE *file = o->file;
 433
 434        fputs(diff_line_prefix(o), file);
 435
 436        if (len == 0) {
 437                has_trailing_newline = (first == '\n');
 438                has_trailing_carriage_return = (!has_trailing_newline &&
 439                                                (first == '\r'));
 440                nofirst = has_trailing_newline || has_trailing_carriage_return;
 441        } else {
 442                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 443                if (has_trailing_newline)
 444                        len--;
 445                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 446                if (has_trailing_carriage_return)
 447                        len--;
 448                nofirst = 0;
 449        }
 450
 451        if (len || !nofirst) {
 452                fputs(set, file);
 453                if (!nofirst)
 454                        fputc(first, file);
 455                fwrite(line, len, 1, file);
 456                fputs(reset, file);
 457        }
 458        if (has_trailing_carriage_return)
 459                fputc('\r', file);
 460        if (has_trailing_newline)
 461                fputc('\n', file);
 462}
 463
 464static void emit_line(struct diff_options *o, const char *set, const char *reset,
 465                      const char *line, int len)
 466{
 467        emit_line_0(o, set, reset, line[0], line+1, len-1);
 468}
 469
 470static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 471{
 472        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 473              ecbdata->blank_at_eof_in_preimage &&
 474              ecbdata->blank_at_eof_in_postimage &&
 475              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 476              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 477                return 0;
 478        return ws_blank_line(line, len, ecbdata->ws_rule);
 479}
 480
 481static void emit_add_line(const char *reset,
 482                          struct emit_callback *ecbdata,
 483                          const char *line, int len)
 484{
 485        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 486        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 487
 488        if (!*ws)
 489                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 490        else if (new_blank_line_at_eof(ecbdata, line, len))
 491                /* Blank line at EOF - paint '+' as well */
 492                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 493        else {
 494                /* Emit just the prefix, then the rest. */
 495                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 496                ws_check_emit(line, len, ecbdata->ws_rule,
 497                              ecbdata->opt->file, set, reset, ws);
 498        }
 499}
 500
 501static void emit_hunk_header(struct emit_callback *ecbdata,
 502                             const char *line, int len)
 503{
 504        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 505        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 506        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 507        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 508        static const char atat[2] = { '@', '@' };
 509        const char *cp, *ep;
 510        struct strbuf msgbuf = STRBUF_INIT;
 511        int org_len = len;
 512        int i = 1;
 513
 514        /*
 515         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 516         * it always is at least 10 bytes long.
 517         */
 518        if (len < 10 ||
 519            memcmp(line, atat, 2) ||
 520            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 521                emit_line(ecbdata->opt, context, reset, line, len);
 522                return;
 523        }
 524        ep += 2; /* skip over @@ */
 525
 526        /* The hunk header in fraginfo color */
 527        strbuf_addstr(&msgbuf, frag);
 528        strbuf_add(&msgbuf, line, ep - line);
 529        strbuf_addstr(&msgbuf, reset);
 530
 531        /*
 532         * trailing "\r\n"
 533         */
 534        for ( ; i < 3; i++)
 535                if (line[len - i] == '\r' || line[len - i] == '\n')
 536                        len--;
 537
 538        /* blank before the func header */
 539        for (cp = ep; ep - line < len; ep++)
 540                if (*ep != ' ' && *ep != '\t')
 541                        break;
 542        if (ep != cp) {
 543                strbuf_addstr(&msgbuf, context);
 544                strbuf_add(&msgbuf, cp, ep - cp);
 545                strbuf_addstr(&msgbuf, reset);
 546        }
 547
 548        if (ep < line + len) {
 549                strbuf_addstr(&msgbuf, func);
 550                strbuf_add(&msgbuf, ep, line + len - ep);
 551                strbuf_addstr(&msgbuf, reset);
 552        }
 553
 554        strbuf_add(&msgbuf, line + len, org_len - len);
 555        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 556        strbuf_release(&msgbuf);
 557}
 558
 559static struct diff_tempfile *claim_diff_tempfile(void) {
 560        int i;
 561        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 562                if (!diff_temp[i].name)
 563                        return diff_temp + i;
 564        die("BUG: diff is failing to clean up its tempfiles");
 565}
 566
 567static int remove_tempfile_installed;
 568
 569static void remove_tempfile(void)
 570{
 571        int i;
 572        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 573                if (diff_temp[i].name == diff_temp[i].tmp_path)
 574                        unlink_or_warn(diff_temp[i].name);
 575                diff_temp[i].name = NULL;
 576        }
 577}
 578
 579static void remove_tempfile_on_signal(int signo)
 580{
 581        remove_tempfile();
 582        sigchain_pop(signo);
 583        raise(signo);
 584}
 585
 586static void print_line_count(FILE *file, int count)
 587{
 588        switch (count) {
 589        case 0:
 590                fprintf(file, "0,0");
 591                break;
 592        case 1:
 593                fprintf(file, "1");
 594                break;
 595        default:
 596                fprintf(file, "1,%d", count);
 597                break;
 598        }
 599}
 600
 601static void emit_rewrite_lines(struct emit_callback *ecb,
 602                               int prefix, const char *data, int size)
 603{
 604        const char *endp = NULL;
 605        static const char *nneof = " No newline at end of file\n";
 606        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 607        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 608
 609        while (0 < size) {
 610                int len;
 611
 612                endp = memchr(data, '\n', size);
 613                len = endp ? (endp - data + 1) : size;
 614                if (prefix != '+') {
 615                        ecb->lno_in_preimage++;
 616                        emit_line_0(ecb->opt, old, reset, '-',
 617                                    data, len);
 618                } else {
 619                        ecb->lno_in_postimage++;
 620                        emit_add_line(reset, ecb, data, len);
 621                }
 622                size -= len;
 623                data += len;
 624        }
 625        if (!endp) {
 626                const char *context = diff_get_color(ecb->color_diff,
 627                                                     DIFF_CONTEXT);
 628                putc('\n', ecb->opt->file);
 629                emit_line_0(ecb->opt, context, reset, '\\',
 630                            nneof, strlen(nneof));
 631        }
 632}
 633
 634static void emit_rewrite_diff(const char *name_a,
 635                              const char *name_b,
 636                              struct diff_filespec *one,
 637                              struct diff_filespec *two,
 638                              struct userdiff_driver *textconv_one,
 639                              struct userdiff_driver *textconv_two,
 640                              struct diff_options *o)
 641{
 642        int lc_a, lc_b;
 643        const char *name_a_tab, *name_b_tab;
 644        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 645        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 646        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 647        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 648        const char *a_prefix, *b_prefix;
 649        char *data_one, *data_two;
 650        size_t size_one, size_two;
 651        struct emit_callback ecbdata;
 652        const char *line_prefix = diff_line_prefix(o);
 653
 654        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 655                a_prefix = o->b_prefix;
 656                b_prefix = o->a_prefix;
 657        } else {
 658                a_prefix = o->a_prefix;
 659                b_prefix = o->b_prefix;
 660        }
 661
 662        name_a += (*name_a == '/');
 663        name_b += (*name_b == '/');
 664        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 665        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 666
 667        strbuf_reset(&a_name);
 668        strbuf_reset(&b_name);
 669        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 670        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 671
 672        size_one = fill_textconv(textconv_one, one, &data_one);
 673        size_two = fill_textconv(textconv_two, two, &data_two);
 674
 675        memset(&ecbdata, 0, sizeof(ecbdata));
 676        ecbdata.color_diff = want_color(o->use_color);
 677        ecbdata.found_changesp = &o->found_changes;
 678        ecbdata.ws_rule = whitespace_rule(name_b);
 679        ecbdata.opt = o;
 680        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 681                mmfile_t mf1, mf2;
 682                mf1.ptr = (char *)data_one;
 683                mf2.ptr = (char *)data_two;
 684                mf1.size = size_one;
 685                mf2.size = size_two;
 686                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 687        }
 688        ecbdata.lno_in_preimage = 1;
 689        ecbdata.lno_in_postimage = 1;
 690
 691        lc_a = count_lines(data_one, size_one);
 692        lc_b = count_lines(data_two, size_two);
 693        fprintf(o->file,
 694                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 695                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 696                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 697                line_prefix, fraginfo);
 698        if (!o->irreversible_delete)
 699                print_line_count(o->file, lc_a);
 700        else
 701                fprintf(o->file, "?,?");
 702        fprintf(o->file, " +");
 703        print_line_count(o->file, lc_b);
 704        fprintf(o->file, " @@%s\n", reset);
 705        if (lc_a && !o->irreversible_delete)
 706                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 707        if (lc_b)
 708                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 709        if (textconv_one)
 710                free((char *)data_one);
 711        if (textconv_two)
 712                free((char *)data_two);
 713}
 714
 715struct diff_words_buffer {
 716        mmfile_t text;
 717        long alloc;
 718        struct diff_words_orig {
 719                const char *begin, *end;
 720        } *orig;
 721        int orig_nr, orig_alloc;
 722};
 723
 724static void diff_words_append(char *line, unsigned long len,
 725                struct diff_words_buffer *buffer)
 726{
 727        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 728        line++;
 729        len--;
 730        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 731        buffer->text.size += len;
 732        buffer->text.ptr[buffer->text.size] = '\0';
 733}
 734
 735struct diff_words_style_elem {
 736        const char *prefix;
 737        const char *suffix;
 738        const char *color; /* NULL; filled in by the setup code if
 739                            * color is enabled */
 740};
 741
 742struct diff_words_style {
 743        enum diff_words_type type;
 744        struct diff_words_style_elem new, old, ctx;
 745        const char *newline;
 746};
 747
 748static struct diff_words_style diff_words_styles[] = {
 749        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 750        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 751        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 752};
 753
 754struct diff_words_data {
 755        struct diff_words_buffer minus, plus;
 756        const char *current_plus;
 757        int last_minus;
 758        struct diff_options *opt;
 759        regex_t *word_regex;
 760        enum diff_words_type type;
 761        struct diff_words_style *style;
 762};
 763
 764static int fn_out_diff_words_write_helper(FILE *fp,
 765                                          struct diff_words_style_elem *st_el,
 766                                          const char *newline,
 767                                          size_t count, const char *buf,
 768                                          const char *line_prefix)
 769{
 770        int print = 0;
 771
 772        while (count) {
 773                char *p = memchr(buf, '\n', count);
 774                if (print)
 775                        fputs(line_prefix, fp);
 776                if (p != buf) {
 777                        if (st_el->color && fputs(st_el->color, fp) < 0)
 778                                return -1;
 779                        if (fputs(st_el->prefix, fp) < 0 ||
 780                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 781                            fputs(st_el->suffix, fp) < 0)
 782                                return -1;
 783                        if (st_el->color && *st_el->color
 784                            && fputs(GIT_COLOR_RESET, fp) < 0)
 785                                return -1;
 786                }
 787                if (!p)
 788                        return 0;
 789                if (fputs(newline, fp) < 0)
 790                        return -1;
 791                count -= p + 1 - buf;
 792                buf = p + 1;
 793                print = 1;
 794        }
 795        return 0;
 796}
 797
 798/*
 799 * '--color-words' algorithm can be described as:
 800 *
 801 *   1. collect a the minus/plus lines of a diff hunk, divided into
 802 *      minus-lines and plus-lines;
 803 *
 804 *   2. break both minus-lines and plus-lines into words and
 805 *      place them into two mmfile_t with one word for each line;
 806 *
 807 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 808 *
 809 * And for the common parts of the both file, we output the plus side text.
 810 * diff_words->current_plus is used to trace the current position of the plus file
 811 * which printed. diff_words->last_minus is used to trace the last minus word
 812 * printed.
 813 *
 814 * For '--graph' to work with '--color-words', we need to output the graph prefix
 815 * on each line of color words output. Generally, there are two conditions on
 816 * which we should output the prefix.
 817 *
 818 *   1. diff_words->last_minus == 0 &&
 819 *      diff_words->current_plus == diff_words->plus.text.ptr
 820 *
 821 *      that is: the plus text must start as a new line, and if there is no minus
 822 *      word printed, a graph prefix must be printed.
 823 *
 824 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 825 *      *(diff_words->current_plus - 1) == '\n'
 826 *
 827 *      that is: a graph prefix must be printed following a '\n'
 828 */
 829static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 830{
 831        if ((diff_words->last_minus == 0 &&
 832                diff_words->current_plus == diff_words->plus.text.ptr) ||
 833                (diff_words->current_plus > diff_words->plus.text.ptr &&
 834                *(diff_words->current_plus - 1) == '\n')) {
 835                return 1;
 836        } else {
 837                return 0;
 838        }
 839}
 840
 841static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 842{
 843        struct diff_words_data *diff_words = priv;
 844        struct diff_words_style *style = diff_words->style;
 845        int minus_first, minus_len, plus_first, plus_len;
 846        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 847        struct diff_options *opt = diff_words->opt;
 848        const char *line_prefix;
 849
 850        if (line[0] != '@' || parse_hunk_header(line, len,
 851                        &minus_first, &minus_len, &plus_first, &plus_len))
 852                return;
 853
 854        assert(opt);
 855        line_prefix = diff_line_prefix(opt);
 856
 857        /* POSIX requires that first be decremented by one if len == 0... */
 858        if (minus_len) {
 859                minus_begin = diff_words->minus.orig[minus_first].begin;
 860                minus_end =
 861                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 862        } else
 863                minus_begin = minus_end =
 864                        diff_words->minus.orig[minus_first].end;
 865
 866        if (plus_len) {
 867                plus_begin = diff_words->plus.orig[plus_first].begin;
 868                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 869        } else
 870                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 871
 872        if (color_words_output_graph_prefix(diff_words)) {
 873                fputs(line_prefix, diff_words->opt->file);
 874        }
 875        if (diff_words->current_plus != plus_begin) {
 876                fn_out_diff_words_write_helper(diff_words->opt->file,
 877                                &style->ctx, style->newline,
 878                                plus_begin - diff_words->current_plus,
 879                                diff_words->current_plus, line_prefix);
 880                if (*(plus_begin - 1) == '\n')
 881                        fputs(line_prefix, diff_words->opt->file);
 882        }
 883        if (minus_begin != minus_end) {
 884                fn_out_diff_words_write_helper(diff_words->opt->file,
 885                                &style->old, style->newline,
 886                                minus_end - minus_begin, minus_begin,
 887                                line_prefix);
 888        }
 889        if (plus_begin != plus_end) {
 890                fn_out_diff_words_write_helper(diff_words->opt->file,
 891                                &style->new, style->newline,
 892                                plus_end - plus_begin, plus_begin,
 893                                line_prefix);
 894        }
 895
 896        diff_words->current_plus = plus_end;
 897        diff_words->last_minus = minus_first;
 898}
 899
 900/* This function starts looking at *begin, and returns 0 iff a word was found. */
 901static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 902                int *begin, int *end)
 903{
 904        if (word_regex && *begin < buffer->size) {
 905                regmatch_t match[1];
 906                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 907                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 908                                        '\n', match[0].rm_eo - match[0].rm_so);
 909                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 910                        *begin += match[0].rm_so;
 911                        return *begin >= *end;
 912                }
 913                return -1;
 914        }
 915
 916        /* find the next word */
 917        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 918                (*begin)++;
 919        if (*begin >= buffer->size)
 920                return -1;
 921
 922        /* find the end of the word */
 923        *end = *begin + 1;
 924        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 925                (*end)++;
 926
 927        return 0;
 928}
 929
 930/*
 931 * This function splits the words in buffer->text, stores the list with
 932 * newline separator into out, and saves the offsets of the original words
 933 * in buffer->orig.
 934 */
 935static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 936                regex_t *word_regex)
 937{
 938        int i, j;
 939        long alloc = 0;
 940
 941        out->size = 0;
 942        out->ptr = NULL;
 943
 944        /* fake an empty "0th" word */
 945        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 946        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 947        buffer->orig_nr = 1;
 948
 949        for (i = 0; i < buffer->text.size; i++) {
 950                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 951                        return;
 952
 953                /* store original boundaries */
 954                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 955                                buffer->orig_alloc);
 956                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 957                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 958                buffer->orig_nr++;
 959
 960                /* store one word */
 961                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 962                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 963                out->ptr[out->size + j - i] = '\n';
 964                out->size += j - i + 1;
 965
 966                i = j - 1;
 967        }
 968}
 969
 970/* this executes the word diff on the accumulated buffers */
 971static void diff_words_show(struct diff_words_data *diff_words)
 972{
 973        xpparam_t xpp;
 974        xdemitconf_t xecfg;
 975        mmfile_t minus, plus;
 976        struct diff_words_style *style = diff_words->style;
 977
 978        struct diff_options *opt = diff_words->opt;
 979        const char *line_prefix;
 980
 981        assert(opt);
 982        line_prefix = diff_line_prefix(opt);
 983
 984        /* special case: only removal */
 985        if (!diff_words->plus.text.size) {
 986                fputs(line_prefix, diff_words->opt->file);
 987                fn_out_diff_words_write_helper(diff_words->opt->file,
 988                        &style->old, style->newline,
 989                        diff_words->minus.text.size,
 990                        diff_words->minus.text.ptr, line_prefix);
 991                diff_words->minus.text.size = 0;
 992                return;
 993        }
 994
 995        diff_words->current_plus = diff_words->plus.text.ptr;
 996        diff_words->last_minus = 0;
 997
 998        memset(&xpp, 0, sizeof(xpp));
 999        memset(&xecfg, 0, sizeof(xecfg));
1000        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1001        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1002        xpp.flags = 0;
1003        /* as only the hunk header will be parsed, we need a 0-context */
1004        xecfg.ctxlen = 0;
1005        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1006                          &xpp, &xecfg))
1007                die("unable to generate word diff");
1008        free(minus.ptr);
1009        free(plus.ptr);
1010        if (diff_words->current_plus != diff_words->plus.text.ptr +
1011                        diff_words->plus.text.size) {
1012                if (color_words_output_graph_prefix(diff_words))
1013                        fputs(line_prefix, diff_words->opt->file);
1014                fn_out_diff_words_write_helper(diff_words->opt->file,
1015                        &style->ctx, style->newline,
1016                        diff_words->plus.text.ptr + diff_words->plus.text.size
1017                        - diff_words->current_plus, diff_words->current_plus,
1018                        line_prefix);
1019        }
1020        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1021}
1022
1023/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1024static void diff_words_flush(struct emit_callback *ecbdata)
1025{
1026        if (ecbdata->diff_words->minus.text.size ||
1027            ecbdata->diff_words->plus.text.size)
1028                diff_words_show(ecbdata->diff_words);
1029}
1030
1031static void diff_filespec_load_driver(struct diff_filespec *one)
1032{
1033        /* Use already-loaded driver */
1034        if (one->driver)
1035                return;
1036
1037        if (S_ISREG(one->mode))
1038                one->driver = userdiff_find_by_path(one->path);
1039
1040        /* Fallback to default settings */
1041        if (!one->driver)
1042                one->driver = userdiff_find_by_name("default");
1043}
1044
1045static const char *userdiff_word_regex(struct diff_filespec *one)
1046{
1047        diff_filespec_load_driver(one);
1048        return one->driver->word_regex;
1049}
1050
1051static void init_diff_words_data(struct emit_callback *ecbdata,
1052                                 struct diff_options *orig_opts,
1053                                 struct diff_filespec *one,
1054                                 struct diff_filespec *two)
1055{
1056        int i;
1057        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1058        memcpy(o, orig_opts, sizeof(struct diff_options));
1059
1060        ecbdata->diff_words =
1061                xcalloc(1, sizeof(struct diff_words_data));
1062        ecbdata->diff_words->type = o->word_diff;
1063        ecbdata->diff_words->opt = o;
1064        if (!o->word_regex)
1065                o->word_regex = userdiff_word_regex(one);
1066        if (!o->word_regex)
1067                o->word_regex = userdiff_word_regex(two);
1068        if (!o->word_regex)
1069                o->word_regex = diff_word_regex_cfg;
1070        if (o->word_regex) {
1071                ecbdata->diff_words->word_regex = (regex_t *)
1072                        xmalloc(sizeof(regex_t));
1073                if (regcomp(ecbdata->diff_words->word_regex,
1074                            o->word_regex,
1075                            REG_EXTENDED | REG_NEWLINE))
1076                        die ("Invalid regular expression: %s",
1077                             o->word_regex);
1078        }
1079        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1080                if (o->word_diff == diff_words_styles[i].type) {
1081                        ecbdata->diff_words->style =
1082                                &diff_words_styles[i];
1083                        break;
1084                }
1085        }
1086        if (want_color(o->use_color)) {
1087                struct diff_words_style *st = ecbdata->diff_words->style;
1088                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1089                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1090                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1091        }
1092}
1093
1094static void free_diff_words_data(struct emit_callback *ecbdata)
1095{
1096        if (ecbdata->diff_words) {
1097                diff_words_flush(ecbdata);
1098                free (ecbdata->diff_words->opt);
1099                free (ecbdata->diff_words->minus.text.ptr);
1100                free (ecbdata->diff_words->minus.orig);
1101                free (ecbdata->diff_words->plus.text.ptr);
1102                free (ecbdata->diff_words->plus.orig);
1103                if (ecbdata->diff_words->word_regex) {
1104                        regfree(ecbdata->diff_words->word_regex);
1105                        free(ecbdata->diff_words->word_regex);
1106                }
1107                free(ecbdata->diff_words);
1108                ecbdata->diff_words = NULL;
1109        }
1110}
1111
1112const char *diff_get_color(int diff_use_color, enum color_diff ix)
1113{
1114        if (want_color(diff_use_color))
1115                return diff_colors[ix];
1116        return "";
1117}
1118
1119const char *diff_line_prefix(struct diff_options *opt)
1120{
1121        struct strbuf *msgbuf;
1122        if (!opt->output_prefix)
1123                return "";
1124
1125        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1126        return msgbuf->buf;
1127}
1128
1129static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1130{
1131        const char *cp;
1132        unsigned long allot;
1133        size_t l = len;
1134
1135        if (ecb->truncate)
1136                return ecb->truncate(line, len);
1137        cp = line;
1138        allot = l;
1139        while (0 < l) {
1140                (void) utf8_width(&cp, &l);
1141                if (!cp)
1142                        break; /* truncated in the middle? */
1143        }
1144        return allot - l;
1145}
1146
1147static void find_lno(const char *line, struct emit_callback *ecbdata)
1148{
1149        const char *p;
1150        ecbdata->lno_in_preimage = 0;
1151        ecbdata->lno_in_postimage = 0;
1152        p = strchr(line, '-');
1153        if (!p)
1154                return; /* cannot happen */
1155        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1156        p = strchr(p, '+');
1157        if (!p)
1158                return; /* cannot happen */
1159        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1160}
1161
1162static void fn_out_consume(void *priv, char *line, unsigned long len)
1163{
1164        struct emit_callback *ecbdata = priv;
1165        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1166        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1167        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1168        struct diff_options *o = ecbdata->opt;
1169        const char *line_prefix = diff_line_prefix(o);
1170
1171        if (ecbdata->header) {
1172                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1173                strbuf_reset(ecbdata->header);
1174                ecbdata->header = NULL;
1175        }
1176        *(ecbdata->found_changesp) = 1;
1177
1178        if (ecbdata->label_path[0]) {
1179                const char *name_a_tab, *name_b_tab;
1180
1181                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1182                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1183
1184                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1185                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1186                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1187                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1188                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1189        }
1190
1191        if (diff_suppress_blank_empty
1192            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1193                line[0] = '\n';
1194                len = 1;
1195        }
1196
1197        if (line[0] == '@') {
1198                if (ecbdata->diff_words)
1199                        diff_words_flush(ecbdata);
1200                len = sane_truncate_line(ecbdata, line, len);
1201                find_lno(line, ecbdata);
1202                emit_hunk_header(ecbdata, line, len);
1203                if (line[len-1] != '\n')
1204                        putc('\n', ecbdata->opt->file);
1205                return;
1206        }
1207
1208        if (len < 1) {
1209                emit_line(ecbdata->opt, reset, reset, line, len);
1210                if (ecbdata->diff_words
1211                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1212                        fputs("~\n", ecbdata->opt->file);
1213                return;
1214        }
1215
1216        if (ecbdata->diff_words) {
1217                if (line[0] == '-') {
1218                        diff_words_append(line, len,
1219                                          &ecbdata->diff_words->minus);
1220                        return;
1221                } else if (line[0] == '+') {
1222                        diff_words_append(line, len,
1223                                          &ecbdata->diff_words->plus);
1224                        return;
1225                } else if (starts_with(line, "\\ ")) {
1226                        /*
1227                         * Eat the "no newline at eof" marker as if we
1228                         * saw a "+" or "-" line with nothing on it,
1229                         * and return without diff_words_flush() to
1230                         * defer processing. If this is the end of
1231                         * preimage, more "+" lines may come after it.
1232                         */
1233                        return;
1234                }
1235                diff_words_flush(ecbdata);
1236                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1237                        emit_line(ecbdata->opt, context, reset, line, len);
1238                        fputs("~\n", ecbdata->opt->file);
1239                } else {
1240                        /*
1241                         * Skip the prefix character, if any.  With
1242                         * diff_suppress_blank_empty, there may be
1243                         * none.
1244                         */
1245                        if (line[0] != '\n') {
1246                              line++;
1247                              len--;
1248                        }
1249                        emit_line(ecbdata->opt, context, reset, line, len);
1250                }
1251                return;
1252        }
1253
1254        if (line[0] != '+') {
1255                const char *color =
1256                        diff_get_color(ecbdata->color_diff,
1257                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_CONTEXT);
1258                ecbdata->lno_in_preimage++;
1259                if (line[0] == ' ')
1260                        ecbdata->lno_in_postimage++;
1261                emit_line(ecbdata->opt, color, reset, line, len);
1262        } else {
1263                ecbdata->lno_in_postimage++;
1264                emit_add_line(reset, ecbdata, line + 1, len - 1);
1265        }
1266}
1267
1268static char *pprint_rename(const char *a, const char *b)
1269{
1270        const char *old = a;
1271        const char *new = b;
1272        struct strbuf name = STRBUF_INIT;
1273        int pfx_length, sfx_length;
1274        int pfx_adjust_for_slash;
1275        int len_a = strlen(a);
1276        int len_b = strlen(b);
1277        int a_midlen, b_midlen;
1278        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1279        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1280
1281        if (qlen_a || qlen_b) {
1282                quote_c_style(a, &name, NULL, 0);
1283                strbuf_addstr(&name, " => ");
1284                quote_c_style(b, &name, NULL, 0);
1285                return strbuf_detach(&name, NULL);
1286        }
1287
1288        /* Find common prefix */
1289        pfx_length = 0;
1290        while (*old && *new && *old == *new) {
1291                if (*old == '/')
1292                        pfx_length = old - a + 1;
1293                old++;
1294                new++;
1295        }
1296
1297        /* Find common suffix */
1298        old = a + len_a;
1299        new = b + len_b;
1300        sfx_length = 0;
1301        /*
1302         * If there is a common prefix, it must end in a slash.  In
1303         * that case we let this loop run 1 into the prefix to see the
1304         * same slash.
1305         *
1306         * If there is no common prefix, we cannot do this as it would
1307         * underrun the input strings.
1308         */
1309        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1310        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1311               b + pfx_length - pfx_adjust_for_slash <= new &&
1312               *old == *new) {
1313                if (*old == '/')
1314                        sfx_length = len_a - (old - a);
1315                old--;
1316                new--;
1317        }
1318
1319        /*
1320         * pfx{mid-a => mid-b}sfx
1321         * {pfx-a => pfx-b}sfx
1322         * pfx{sfx-a => sfx-b}
1323         * name-a => name-b
1324         */
1325        a_midlen = len_a - pfx_length - sfx_length;
1326        b_midlen = len_b - pfx_length - sfx_length;
1327        if (a_midlen < 0)
1328                a_midlen = 0;
1329        if (b_midlen < 0)
1330                b_midlen = 0;
1331
1332        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1333        if (pfx_length + sfx_length) {
1334                strbuf_add(&name, a, pfx_length);
1335                strbuf_addch(&name, '{');
1336        }
1337        strbuf_add(&name, a + pfx_length, a_midlen);
1338        strbuf_addstr(&name, " => ");
1339        strbuf_add(&name, b + pfx_length, b_midlen);
1340        if (pfx_length + sfx_length) {
1341                strbuf_addch(&name, '}');
1342                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1343        }
1344        return strbuf_detach(&name, NULL);
1345}
1346
1347struct diffstat_t {
1348        int nr;
1349        int alloc;
1350        struct diffstat_file {
1351                char *from_name;
1352                char *name;
1353                char *print_name;
1354                unsigned is_unmerged:1;
1355                unsigned is_binary:1;
1356                unsigned is_renamed:1;
1357                unsigned is_interesting:1;
1358                uintmax_t added, deleted;
1359        } **files;
1360};
1361
1362static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1363                                          const char *name_a,
1364                                          const char *name_b)
1365{
1366        struct diffstat_file *x;
1367        x = xcalloc(1, sizeof(*x));
1368        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1369        diffstat->files[diffstat->nr++] = x;
1370        if (name_b) {
1371                x->from_name = xstrdup(name_a);
1372                x->name = xstrdup(name_b);
1373                x->is_renamed = 1;
1374        }
1375        else {
1376                x->from_name = NULL;
1377                x->name = xstrdup(name_a);
1378        }
1379        return x;
1380}
1381
1382static void diffstat_consume(void *priv, char *line, unsigned long len)
1383{
1384        struct diffstat_t *diffstat = priv;
1385        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1386
1387        if (line[0] == '+')
1388                x->added++;
1389        else if (line[0] == '-')
1390                x->deleted++;
1391}
1392
1393const char mime_boundary_leader[] = "------------";
1394
1395static int scale_linear(int it, int width, int max_change)
1396{
1397        if (!it)
1398                return 0;
1399        /*
1400         * make sure that at least one '-' or '+' is printed if
1401         * there is any change to this path. The easiest way is to
1402         * scale linearly as if the alloted width is one column shorter
1403         * than it is, and then add 1 to the result.
1404         */
1405        return 1 + (it * (width - 1) / max_change);
1406}
1407
1408static void show_name(FILE *file,
1409                      const char *prefix, const char *name, int len)
1410{
1411        fprintf(file, " %s%-*s |", prefix, len, name);
1412}
1413
1414static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1415{
1416        if (cnt <= 0)
1417                return;
1418        fprintf(file, "%s", set);
1419        while (cnt--)
1420                putc(ch, file);
1421        fprintf(file, "%s", reset);
1422}
1423
1424static void fill_print_name(struct diffstat_file *file)
1425{
1426        char *pname;
1427
1428        if (file->print_name)
1429                return;
1430
1431        if (!file->is_renamed) {
1432                struct strbuf buf = STRBUF_INIT;
1433                if (quote_c_style(file->name, &buf, NULL, 0)) {
1434                        pname = strbuf_detach(&buf, NULL);
1435                } else {
1436                        pname = file->name;
1437                        strbuf_release(&buf);
1438                }
1439        } else {
1440                pname = pprint_rename(file->from_name, file->name);
1441        }
1442        file->print_name = pname;
1443}
1444
1445int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1446{
1447        struct strbuf sb = STRBUF_INIT;
1448        int ret;
1449
1450        if (!files) {
1451                assert(insertions == 0 && deletions == 0);
1452                return fprintf(fp, "%s\n", " 0 files changed");
1453        }
1454
1455        strbuf_addf(&sb,
1456                    (files == 1) ? " %d file changed" : " %d files changed",
1457                    files);
1458
1459        /*
1460         * For binary diff, the caller may want to print "x files
1461         * changed" with insertions == 0 && deletions == 0.
1462         *
1463         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1464         * is probably less confusing (i.e skip over "2 files changed
1465         * but nothing about added/removed lines? Is this a bug in Git?").
1466         */
1467        if (insertions || deletions == 0) {
1468                strbuf_addf(&sb,
1469                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1470                            insertions);
1471        }
1472
1473        if (deletions || insertions == 0) {
1474                strbuf_addf(&sb,
1475                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1476                            deletions);
1477        }
1478        strbuf_addch(&sb, '\n');
1479        ret = fputs(sb.buf, fp);
1480        strbuf_release(&sb);
1481        return ret;
1482}
1483
1484static void show_stats(struct diffstat_t *data, struct diff_options *options)
1485{
1486        int i, len, add, del, adds = 0, dels = 0;
1487        uintmax_t max_change = 0, max_len = 0;
1488        int total_files = data->nr, count;
1489        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1490        const char *reset, *add_c, *del_c;
1491        const char *line_prefix = "";
1492        int extra_shown = 0;
1493
1494        if (data->nr == 0)
1495                return;
1496
1497        line_prefix = diff_line_prefix(options);
1498        count = options->stat_count ? options->stat_count : data->nr;
1499
1500        reset = diff_get_color_opt(options, DIFF_RESET);
1501        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1502        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1503
1504        /*
1505         * Find the longest filename and max number of changes
1506         */
1507        for (i = 0; (i < count) && (i < data->nr); i++) {
1508                struct diffstat_file *file = data->files[i];
1509                uintmax_t change = file->added + file->deleted;
1510
1511                if (!file->is_interesting && (change == 0)) {
1512                        count++; /* not shown == room for one more */
1513                        continue;
1514                }
1515                fill_print_name(file);
1516                len = strlen(file->print_name);
1517                if (max_len < len)
1518                        max_len = len;
1519
1520                if (file->is_unmerged) {
1521                        /* "Unmerged" is 8 characters */
1522                        bin_width = bin_width < 8 ? 8 : bin_width;
1523                        continue;
1524                }
1525                if (file->is_binary) {
1526                        /* "Bin XXX -> YYY bytes" */
1527                        int w = 14 + decimal_width(file->added)
1528                                + decimal_width(file->deleted);
1529                        bin_width = bin_width < w ? w : bin_width;
1530                        /* Display change counts aligned with "Bin" */
1531                        number_width = 3;
1532                        continue;
1533                }
1534
1535                if (max_change < change)
1536                        max_change = change;
1537        }
1538        count = i; /* where we can stop scanning in data->files[] */
1539
1540        /*
1541         * We have width = stat_width or term_columns() columns total.
1542         * We want a maximum of min(max_len, stat_name_width) for the name part.
1543         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1544         * We also need 1 for " " and 4 + decimal_width(max_change)
1545         * for " | NNNN " and one the empty column at the end, altogether
1546         * 6 + decimal_width(max_change).
1547         *
1548         * If there's not enough space, we will use the smaller of
1549         * stat_name_width (if set) and 5/8*width for the filename,
1550         * and the rest for constant elements + graph part, but no more
1551         * than stat_graph_width for the graph part.
1552         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1553         * for the standard terminal size).
1554         *
1555         * In other words: stat_width limits the maximum width, and
1556         * stat_name_width fixes the maximum width of the filename,
1557         * and is also used to divide available columns if there
1558         * aren't enough.
1559         *
1560         * Binary files are displayed with "Bin XXX -> YYY bytes"
1561         * instead of the change count and graph. This part is treated
1562         * similarly to the graph part, except that it is not
1563         * "scaled". If total width is too small to accommodate the
1564         * guaranteed minimum width of the filename part and the
1565         * separators and this message, this message will "overflow"
1566         * making the line longer than the maximum width.
1567         */
1568
1569        if (options->stat_width == -1)
1570                width = term_columns() - options->output_prefix_length;
1571        else
1572                width = options->stat_width ? options->stat_width : 80;
1573        number_width = decimal_width(max_change) > number_width ?
1574                decimal_width(max_change) : number_width;
1575
1576        if (options->stat_graph_width == -1)
1577                options->stat_graph_width = diff_stat_graph_width;
1578
1579        /*
1580         * Guarantee 3/8*16==6 for the graph part
1581         * and 5/8*16==10 for the filename part
1582         */
1583        if (width < 16 + 6 + number_width)
1584                width = 16 + 6 + number_width;
1585
1586        /*
1587         * First assign sizes that are wanted, ignoring available width.
1588         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1589         * starting from "XXX" should fit in graph_width.
1590         */
1591        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1592        if (options->stat_graph_width &&
1593            options->stat_graph_width < graph_width)
1594                graph_width = options->stat_graph_width;
1595
1596        name_width = (options->stat_name_width > 0 &&
1597                      options->stat_name_width < max_len) ?
1598                options->stat_name_width : max_len;
1599
1600        /*
1601         * Adjust adjustable widths not to exceed maximum width
1602         */
1603        if (name_width + number_width + 6 + graph_width > width) {
1604                if (graph_width > width * 3/8 - number_width - 6) {
1605                        graph_width = width * 3/8 - number_width - 6;
1606                        if (graph_width < 6)
1607                                graph_width = 6;
1608                }
1609
1610                if (options->stat_graph_width &&
1611                    graph_width > options->stat_graph_width)
1612                        graph_width = options->stat_graph_width;
1613                if (name_width > width - number_width - 6 - graph_width)
1614                        name_width = width - number_width - 6 - graph_width;
1615                else
1616                        graph_width = width - number_width - 6 - name_width;
1617        }
1618
1619        /*
1620         * From here name_width is the width of the name area,
1621         * and graph_width is the width of the graph area.
1622         * max_change is used to scale graph properly.
1623         */
1624        for (i = 0; i < count; i++) {
1625                const char *prefix = "";
1626                struct diffstat_file *file = data->files[i];
1627                char *name = file->print_name;
1628                uintmax_t added = file->added;
1629                uintmax_t deleted = file->deleted;
1630                int name_len;
1631
1632                if (!file->is_interesting && (added + deleted == 0))
1633                        continue;
1634
1635                /*
1636                 * "scale" the filename
1637                 */
1638                len = name_width;
1639                name_len = strlen(name);
1640                if (name_width < name_len) {
1641                        char *slash;
1642                        prefix = "...";
1643                        len -= 3;
1644                        name += name_len - len;
1645                        slash = strchr(name, '/');
1646                        if (slash)
1647                                name = slash;
1648                }
1649
1650                if (file->is_binary) {
1651                        fprintf(options->file, "%s", line_prefix);
1652                        show_name(options->file, prefix, name, len);
1653                        fprintf(options->file, " %*s", number_width, "Bin");
1654                        if (!added && !deleted) {
1655                                putc('\n', options->file);
1656                                continue;
1657                        }
1658                        fprintf(options->file, " %s%"PRIuMAX"%s",
1659                                del_c, deleted, reset);
1660                        fprintf(options->file, " -> ");
1661                        fprintf(options->file, "%s%"PRIuMAX"%s",
1662                                add_c, added, reset);
1663                        fprintf(options->file, " bytes");
1664                        fprintf(options->file, "\n");
1665                        continue;
1666                }
1667                else if (file->is_unmerged) {
1668                        fprintf(options->file, "%s", line_prefix);
1669                        show_name(options->file, prefix, name, len);
1670                        fprintf(options->file, " Unmerged\n");
1671                        continue;
1672                }
1673
1674                /*
1675                 * scale the add/delete
1676                 */
1677                add = added;
1678                del = deleted;
1679
1680                if (graph_width <= max_change) {
1681                        int total = scale_linear(add + del, graph_width, max_change);
1682                        if (total < 2 && add && del)
1683                                /* width >= 2 due to the sanity check */
1684                                total = 2;
1685                        if (add < del) {
1686                                add = scale_linear(add, graph_width, max_change);
1687                                del = total - add;
1688                        } else {
1689                                del = scale_linear(del, graph_width, max_change);
1690                                add = total - del;
1691                        }
1692                }
1693                fprintf(options->file, "%s", line_prefix);
1694                show_name(options->file, prefix, name, len);
1695                fprintf(options->file, " %*"PRIuMAX"%s",
1696                        number_width, added + deleted,
1697                        added + deleted ? " " : "");
1698                show_graph(options->file, '+', add, add_c, reset);
1699                show_graph(options->file, '-', del, del_c, reset);
1700                fprintf(options->file, "\n");
1701        }
1702
1703        for (i = 0; i < data->nr; i++) {
1704                struct diffstat_file *file = data->files[i];
1705                uintmax_t added = file->added;
1706                uintmax_t deleted = file->deleted;
1707
1708                if (file->is_unmerged ||
1709                    (!file->is_interesting && (added + deleted == 0))) {
1710                        total_files--;
1711                        continue;
1712                }
1713
1714                if (!file->is_binary) {
1715                        adds += added;
1716                        dels += deleted;
1717                }
1718                if (i < count)
1719                        continue;
1720                if (!extra_shown)
1721                        fprintf(options->file, "%s ...\n", line_prefix);
1722                extra_shown = 1;
1723        }
1724        fprintf(options->file, "%s", line_prefix);
1725        print_stat_summary(options->file, total_files, adds, dels);
1726}
1727
1728static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1729{
1730        int i, adds = 0, dels = 0, total_files = data->nr;
1731
1732        if (data->nr == 0)
1733                return;
1734
1735        for (i = 0; i < data->nr; i++) {
1736                int added = data->files[i]->added;
1737                int deleted= data->files[i]->deleted;
1738
1739                if (data->files[i]->is_unmerged ||
1740                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1741                        total_files--;
1742                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1743                        adds += added;
1744                        dels += deleted;
1745                }
1746        }
1747        fprintf(options->file, "%s", diff_line_prefix(options));
1748        print_stat_summary(options->file, total_files, adds, dels);
1749}
1750
1751static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1752{
1753        int i;
1754
1755        if (data->nr == 0)
1756                return;
1757
1758        for (i = 0; i < data->nr; i++) {
1759                struct diffstat_file *file = data->files[i];
1760
1761                fprintf(options->file, "%s", diff_line_prefix(options));
1762
1763                if (file->is_binary)
1764                        fprintf(options->file, "-\t-\t");
1765                else
1766                        fprintf(options->file,
1767                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1768                                file->added, file->deleted);
1769                if (options->line_termination) {
1770                        fill_print_name(file);
1771                        if (!file->is_renamed)
1772                                write_name_quoted(file->name, options->file,
1773                                                  options->line_termination);
1774                        else {
1775                                fputs(file->print_name, options->file);
1776                                putc(options->line_termination, options->file);
1777                        }
1778                } else {
1779                        if (file->is_renamed) {
1780                                putc('\0', options->file);
1781                                write_name_quoted(file->from_name, options->file, '\0');
1782                        }
1783                        write_name_quoted(file->name, options->file, '\0');
1784                }
1785        }
1786}
1787
1788struct dirstat_file {
1789        const char *name;
1790        unsigned long changed;
1791};
1792
1793struct dirstat_dir {
1794        struct dirstat_file *files;
1795        int alloc, nr, permille, cumulative;
1796};
1797
1798static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1799                unsigned long changed, const char *base, int baselen)
1800{
1801        unsigned long this_dir = 0;
1802        unsigned int sources = 0;
1803        const char *line_prefix = diff_line_prefix(opt);
1804
1805        while (dir->nr) {
1806                struct dirstat_file *f = dir->files;
1807                int namelen = strlen(f->name);
1808                unsigned long this;
1809                char *slash;
1810
1811                if (namelen < baselen)
1812                        break;
1813                if (memcmp(f->name, base, baselen))
1814                        break;
1815                slash = strchr(f->name + baselen, '/');
1816                if (slash) {
1817                        int newbaselen = slash + 1 - f->name;
1818                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1819                        sources++;
1820                } else {
1821                        this = f->changed;
1822                        dir->files++;
1823                        dir->nr--;
1824                        sources += 2;
1825                }
1826                this_dir += this;
1827        }
1828
1829        /*
1830         * We don't report dirstat's for
1831         *  - the top level
1832         *  - or cases where everything came from a single directory
1833         *    under this directory (sources == 1).
1834         */
1835        if (baselen && sources != 1) {
1836                if (this_dir) {
1837                        int permille = this_dir * 1000 / changed;
1838                        if (permille >= dir->permille) {
1839                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1840                                        permille / 10, permille % 10, baselen, base);
1841                                if (!dir->cumulative)
1842                                        return 0;
1843                        }
1844                }
1845        }
1846        return this_dir;
1847}
1848
1849static int dirstat_compare(const void *_a, const void *_b)
1850{
1851        const struct dirstat_file *a = _a;
1852        const struct dirstat_file *b = _b;
1853        return strcmp(a->name, b->name);
1854}
1855
1856static void show_dirstat(struct diff_options *options)
1857{
1858        int i;
1859        unsigned long changed;
1860        struct dirstat_dir dir;
1861        struct diff_queue_struct *q = &diff_queued_diff;
1862
1863        dir.files = NULL;
1864        dir.alloc = 0;
1865        dir.nr = 0;
1866        dir.permille = options->dirstat_permille;
1867        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1868
1869        changed = 0;
1870        for (i = 0; i < q->nr; i++) {
1871                struct diff_filepair *p = q->queue[i];
1872                const char *name;
1873                unsigned long copied, added, damage;
1874                int content_changed;
1875
1876                name = p->two->path ? p->two->path : p->one->path;
1877
1878                if (p->one->sha1_valid && p->two->sha1_valid)
1879                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1880                else
1881                        content_changed = 1;
1882
1883                if (!content_changed) {
1884                        /*
1885                         * The SHA1 has not changed, so pre-/post-content is
1886                         * identical. We can therefore skip looking at the
1887                         * file contents altogether.
1888                         */
1889                        damage = 0;
1890                        goto found_damage;
1891                }
1892
1893                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1894                        /*
1895                         * In --dirstat-by-file mode, we don't really need to
1896                         * look at the actual file contents at all.
1897                         * The fact that the SHA1 changed is enough for us to
1898                         * add this file to the list of results
1899                         * (with each file contributing equal damage).
1900                         */
1901                        damage = 1;
1902                        goto found_damage;
1903                }
1904
1905                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1906                        diff_populate_filespec(p->one, 0);
1907                        diff_populate_filespec(p->two, 0);
1908                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1909                                               &copied, &added);
1910                        diff_free_filespec_data(p->one);
1911                        diff_free_filespec_data(p->two);
1912                } else if (DIFF_FILE_VALID(p->one)) {
1913                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1914                        copied = added = 0;
1915                        diff_free_filespec_data(p->one);
1916                } else if (DIFF_FILE_VALID(p->two)) {
1917                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1918                        copied = 0;
1919                        added = p->two->size;
1920                        diff_free_filespec_data(p->two);
1921                } else
1922                        continue;
1923
1924                /*
1925                 * Original minus copied is the removed material,
1926                 * added is the new material.  They are both damages
1927                 * made to the preimage.
1928                 * If the resulting damage is zero, we know that
1929                 * diffcore_count_changes() considers the two entries to
1930                 * be identical, but since content_changed is true, we
1931                 * know that there must have been _some_ kind of change,
1932                 * so we force all entries to have damage > 0.
1933                 */
1934                damage = (p->one->size - copied) + added;
1935                if (!damage)
1936                        damage = 1;
1937
1938found_damage:
1939                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1940                dir.files[dir.nr].name = name;
1941                dir.files[dir.nr].changed = damage;
1942                changed += damage;
1943                dir.nr++;
1944        }
1945
1946        /* This can happen even with many files, if everything was renames */
1947        if (!changed)
1948                return;
1949
1950        /* Show all directories with more than x% of the changes */
1951        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1952        gather_dirstat(options, &dir, changed, "", 0);
1953}
1954
1955static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1956{
1957        int i;
1958        unsigned long changed;
1959        struct dirstat_dir dir;
1960
1961        if (data->nr == 0)
1962                return;
1963
1964        dir.files = NULL;
1965        dir.alloc = 0;
1966        dir.nr = 0;
1967        dir.permille = options->dirstat_permille;
1968        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1969
1970        changed = 0;
1971        for (i = 0; i < data->nr; i++) {
1972                struct diffstat_file *file = data->files[i];
1973                unsigned long damage = file->added + file->deleted;
1974                if (file->is_binary)
1975                        /*
1976                         * binary files counts bytes, not lines. Must find some
1977                         * way to normalize binary bytes vs. textual lines.
1978                         * The following heuristic assumes that there are 64
1979                         * bytes per "line".
1980                         * This is stupid and ugly, but very cheap...
1981                         */
1982                        damage = (damage + 63) / 64;
1983                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1984                dir.files[dir.nr].name = file->name;
1985                dir.files[dir.nr].changed = damage;
1986                changed += damage;
1987                dir.nr++;
1988        }
1989
1990        /* This can happen even with many files, if everything was renames */
1991        if (!changed)
1992                return;
1993
1994        /* Show all directories with more than x% of the changes */
1995        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1996        gather_dirstat(options, &dir, changed, "", 0);
1997}
1998
1999static void free_diffstat_info(struct diffstat_t *diffstat)
2000{
2001        int i;
2002        for (i = 0; i < diffstat->nr; i++) {
2003                struct diffstat_file *f = diffstat->files[i];
2004                if (f->name != f->print_name)
2005                        free(f->print_name);
2006                free(f->name);
2007                free(f->from_name);
2008                free(f);
2009        }
2010        free(diffstat->files);
2011}
2012
2013struct checkdiff_t {
2014        const char *filename;
2015        int lineno;
2016        int conflict_marker_size;
2017        struct diff_options *o;
2018        unsigned ws_rule;
2019        unsigned status;
2020};
2021
2022static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2023{
2024        char firstchar;
2025        int cnt;
2026
2027        if (len < marker_size + 1)
2028                return 0;
2029        firstchar = line[0];
2030        switch (firstchar) {
2031        case '=': case '>': case '<': case '|':
2032                break;
2033        default:
2034                return 0;
2035        }
2036        for (cnt = 1; cnt < marker_size; cnt++)
2037                if (line[cnt] != firstchar)
2038                        return 0;
2039        /* line[1] thru line[marker_size-1] are same as firstchar */
2040        if (len < marker_size + 1 || !isspace(line[marker_size]))
2041                return 0;
2042        return 1;
2043}
2044
2045static void checkdiff_consume(void *priv, char *line, unsigned long len)
2046{
2047        struct checkdiff_t *data = priv;
2048        int marker_size = data->conflict_marker_size;
2049        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2050        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2051        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2052        char *err;
2053        const char *line_prefix;
2054
2055        assert(data->o);
2056        line_prefix = diff_line_prefix(data->o);
2057
2058        if (line[0] == '+') {
2059                unsigned bad;
2060                data->lineno++;
2061                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2062                        data->status |= 1;
2063                        fprintf(data->o->file,
2064                                "%s%s:%d: leftover conflict marker\n",
2065                                line_prefix, data->filename, data->lineno);
2066                }
2067                bad = ws_check(line + 1, len - 1, data->ws_rule);
2068                if (!bad)
2069                        return;
2070                data->status |= bad;
2071                err = whitespace_error_string(bad);
2072                fprintf(data->o->file, "%s%s:%d: %s.\n",
2073                        line_prefix, data->filename, data->lineno, err);
2074                free(err);
2075                emit_line(data->o, set, reset, line, 1);
2076                ws_check_emit(line + 1, len - 1, data->ws_rule,
2077                              data->o->file, set, reset, ws);
2078        } else if (line[0] == ' ') {
2079                data->lineno++;
2080        } else if (line[0] == '@') {
2081                char *plus = strchr(line, '+');
2082                if (plus)
2083                        data->lineno = strtol(plus, NULL, 10) - 1;
2084                else
2085                        die("invalid diff");
2086        }
2087}
2088
2089static unsigned char *deflate_it(char *data,
2090                                 unsigned long size,
2091                                 unsigned long *result_size)
2092{
2093        int bound;
2094        unsigned char *deflated;
2095        git_zstream stream;
2096
2097        git_deflate_init(&stream, zlib_compression_level);
2098        bound = git_deflate_bound(&stream, size);
2099        deflated = xmalloc(bound);
2100        stream.next_out = deflated;
2101        stream.avail_out = bound;
2102
2103        stream.next_in = (unsigned char *)data;
2104        stream.avail_in = size;
2105        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2106                ; /* nothing */
2107        git_deflate_end(&stream);
2108        *result_size = stream.total_out;
2109        return deflated;
2110}
2111
2112static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2113                                  const char *prefix)
2114{
2115        void *cp;
2116        void *delta;
2117        void *deflated;
2118        void *data;
2119        unsigned long orig_size;
2120        unsigned long delta_size;
2121        unsigned long deflate_size;
2122        unsigned long data_size;
2123
2124        /* We could do deflated delta, or we could do just deflated two,
2125         * whichever is smaller.
2126         */
2127        delta = NULL;
2128        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2129        if (one->size && two->size) {
2130                delta = diff_delta(one->ptr, one->size,
2131                                   two->ptr, two->size,
2132                                   &delta_size, deflate_size);
2133                if (delta) {
2134                        void *to_free = delta;
2135                        orig_size = delta_size;
2136                        delta = deflate_it(delta, delta_size, &delta_size);
2137                        free(to_free);
2138                }
2139        }
2140
2141        if (delta && delta_size < deflate_size) {
2142                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2143                free(deflated);
2144                data = delta;
2145                data_size = delta_size;
2146        }
2147        else {
2148                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2149                free(delta);
2150                data = deflated;
2151                data_size = deflate_size;
2152        }
2153
2154        /* emit data encoded in base85 */
2155        cp = data;
2156        while (data_size) {
2157                int bytes = (52 < data_size) ? 52 : data_size;
2158                char line[70];
2159                data_size -= bytes;
2160                if (bytes <= 26)
2161                        line[0] = bytes + 'A' - 1;
2162                else
2163                        line[0] = bytes - 26 + 'a' - 1;
2164                encode_85(line + 1, cp, bytes);
2165                cp = (char *) cp + bytes;
2166                fprintf(file, "%s", prefix);
2167                fputs(line, file);
2168                fputc('\n', file);
2169        }
2170        fprintf(file, "%s\n", prefix);
2171        free(data);
2172}
2173
2174static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2175                             const char *prefix)
2176{
2177        fprintf(file, "%sGIT binary patch\n", prefix);
2178        emit_binary_diff_body(file, one, two, prefix);
2179        emit_binary_diff_body(file, two, one, prefix);
2180}
2181
2182int diff_filespec_is_binary(struct diff_filespec *one)
2183{
2184        if (one->is_binary == -1) {
2185                diff_filespec_load_driver(one);
2186                if (one->driver->binary != -1)
2187                        one->is_binary = one->driver->binary;
2188                else {
2189                        if (!one->data && DIFF_FILE_VALID(one))
2190                                diff_populate_filespec(one, CHECK_BINARY);
2191                        if (one->is_binary == -1 && one->data)
2192                                one->is_binary = buffer_is_binary(one->data,
2193                                                one->size);
2194                        if (one->is_binary == -1)
2195                                one->is_binary = 0;
2196                }
2197        }
2198        return one->is_binary;
2199}
2200
2201static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2202{
2203        diff_filespec_load_driver(one);
2204        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2205}
2206
2207void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2208{
2209        if (!options->a_prefix)
2210                options->a_prefix = a;
2211        if (!options->b_prefix)
2212                options->b_prefix = b;
2213}
2214
2215struct userdiff_driver *get_textconv(struct diff_filespec *one)
2216{
2217        if (!DIFF_FILE_VALID(one))
2218                return NULL;
2219
2220        diff_filespec_load_driver(one);
2221        return userdiff_get_textconv(one->driver);
2222}
2223
2224static void builtin_diff(const char *name_a,
2225                         const char *name_b,
2226                         struct diff_filespec *one,
2227                         struct diff_filespec *two,
2228                         const char *xfrm_msg,
2229                         int must_show_header,
2230                         struct diff_options *o,
2231                         int complete_rewrite)
2232{
2233        mmfile_t mf1, mf2;
2234        const char *lbl[2];
2235        char *a_one, *b_two;
2236        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2237        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2238        const char *a_prefix, *b_prefix;
2239        struct userdiff_driver *textconv_one = NULL;
2240        struct userdiff_driver *textconv_two = NULL;
2241        struct strbuf header = STRBUF_INIT;
2242        const char *line_prefix = diff_line_prefix(o);
2243
2244        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2245                        (!one->mode || S_ISGITLINK(one->mode)) &&
2246                        (!two->mode || S_ISGITLINK(two->mode))) {
2247                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2248                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2249                show_submodule_summary(o->file, one->path ? one->path : two->path,
2250                                line_prefix,
2251                                one->sha1, two->sha1, two->dirty_submodule,
2252                                meta, del, add, reset);
2253                return;
2254        }
2255
2256        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2257                textconv_one = get_textconv(one);
2258                textconv_two = get_textconv(two);
2259        }
2260
2261        diff_set_mnemonic_prefix(o, "a/", "b/");
2262        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2263                a_prefix = o->b_prefix;
2264                b_prefix = o->a_prefix;
2265        } else {
2266                a_prefix = o->a_prefix;
2267                b_prefix = o->b_prefix;
2268        }
2269
2270        /* Never use a non-valid filename anywhere if at all possible */
2271        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2272        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2273
2274        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2275        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2276        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2277        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2278        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2279        if (lbl[0][0] == '/') {
2280                /* /dev/null */
2281                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2282                if (xfrm_msg)
2283                        strbuf_addstr(&header, xfrm_msg);
2284                must_show_header = 1;
2285        }
2286        else if (lbl[1][0] == '/') {
2287                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2288                if (xfrm_msg)
2289                        strbuf_addstr(&header, xfrm_msg);
2290                must_show_header = 1;
2291        }
2292        else {
2293                if (one->mode != two->mode) {
2294                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2295                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2296                        must_show_header = 1;
2297                }
2298                if (xfrm_msg)
2299                        strbuf_addstr(&header, xfrm_msg);
2300
2301                /*
2302                 * we do not run diff between different kind
2303                 * of objects.
2304                 */
2305                if ((one->mode ^ two->mode) & S_IFMT)
2306                        goto free_ab_and_return;
2307                if (complete_rewrite &&
2308                    (textconv_one || !diff_filespec_is_binary(one)) &&
2309                    (textconv_two || !diff_filespec_is_binary(two))) {
2310                        fprintf(o->file, "%s", header.buf);
2311                        strbuf_reset(&header);
2312                        emit_rewrite_diff(name_a, name_b, one, two,
2313                                                textconv_one, textconv_two, o);
2314                        o->found_changes = 1;
2315                        goto free_ab_and_return;
2316                }
2317        }
2318
2319        if (o->irreversible_delete && lbl[1][0] == '/') {
2320                fprintf(o->file, "%s", header.buf);
2321                strbuf_reset(&header);
2322                goto free_ab_and_return;
2323        } else if (!DIFF_OPT_TST(o, TEXT) &&
2324            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2325              (!textconv_two && diff_filespec_is_binary(two)) )) {
2326                if (!one->data && !two->data &&
2327                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2328                    !DIFF_OPT_TST(o, BINARY)) {
2329                        if (!hashcmp(one->sha1, two->sha1)) {
2330                                if (must_show_header)
2331                                        fprintf(o->file, "%s", header.buf);
2332                                goto free_ab_and_return;
2333                        }
2334                        fprintf(o->file, "%s", header.buf);
2335                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2336                                line_prefix, lbl[0], lbl[1]);
2337                        goto free_ab_and_return;
2338                }
2339                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2340                        die("unable to read files to diff");
2341                /* Quite common confusing case */
2342                if (mf1.size == mf2.size &&
2343                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2344                        if (must_show_header)
2345                                fprintf(o->file, "%s", header.buf);
2346                        goto free_ab_and_return;
2347                }
2348                fprintf(o->file, "%s", header.buf);
2349                strbuf_reset(&header);
2350                if (DIFF_OPT_TST(o, BINARY))
2351                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2352                else
2353                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2354                                line_prefix, lbl[0], lbl[1]);
2355                o->found_changes = 1;
2356        } else {
2357                /* Crazy xdl interfaces.. */
2358                const char *diffopts = getenv("GIT_DIFF_OPTS");
2359                const char *v;
2360                xpparam_t xpp;
2361                xdemitconf_t xecfg;
2362                struct emit_callback ecbdata;
2363                const struct userdiff_funcname *pe;
2364
2365                if (must_show_header) {
2366                        fprintf(o->file, "%s", header.buf);
2367                        strbuf_reset(&header);
2368                }
2369
2370                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2371                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2372
2373                pe = diff_funcname_pattern(one);
2374                if (!pe)
2375                        pe = diff_funcname_pattern(two);
2376
2377                memset(&xpp, 0, sizeof(xpp));
2378                memset(&xecfg, 0, sizeof(xecfg));
2379                memset(&ecbdata, 0, sizeof(ecbdata));
2380                ecbdata.label_path = lbl;
2381                ecbdata.color_diff = want_color(o->use_color);
2382                ecbdata.found_changesp = &o->found_changes;
2383                ecbdata.ws_rule = whitespace_rule(name_b);
2384                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2385                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2386                ecbdata.opt = o;
2387                ecbdata.header = header.len ? &header : NULL;
2388                xpp.flags = o->xdl_opts;
2389                xecfg.ctxlen = o->context;
2390                xecfg.interhunkctxlen = o->interhunkcontext;
2391                xecfg.flags = XDL_EMIT_FUNCNAMES;
2392                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2393                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2394                if (pe)
2395                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2396                if (!diffopts)
2397                        ;
2398                else if (skip_prefix(diffopts, "--unified=", &v))
2399                        xecfg.ctxlen = strtoul(v, NULL, 10);
2400                else if (skip_prefix(diffopts, "-u", &v))
2401                        xecfg.ctxlen = strtoul(v, NULL, 10);
2402                if (o->word_diff)
2403                        init_diff_words_data(&ecbdata, o, one, two);
2404                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2405                                  &xpp, &xecfg))
2406                        die("unable to generate diff for %s", one->path);
2407                if (o->word_diff)
2408                        free_diff_words_data(&ecbdata);
2409                if (textconv_one)
2410                        free(mf1.ptr);
2411                if (textconv_two)
2412                        free(mf2.ptr);
2413                xdiff_clear_find_func(&xecfg);
2414        }
2415
2416 free_ab_and_return:
2417        strbuf_release(&header);
2418        diff_free_filespec_data(one);
2419        diff_free_filespec_data(two);
2420        free(a_one);
2421        free(b_two);
2422        return;
2423}
2424
2425static void builtin_diffstat(const char *name_a, const char *name_b,
2426                             struct diff_filespec *one,
2427                             struct diff_filespec *two,
2428                             struct diffstat_t *diffstat,
2429                             struct diff_options *o,
2430                             struct diff_filepair *p)
2431{
2432        mmfile_t mf1, mf2;
2433        struct diffstat_file *data;
2434        int same_contents;
2435        int complete_rewrite = 0;
2436
2437        if (!DIFF_PAIR_UNMERGED(p)) {
2438                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2439                        complete_rewrite = 1;
2440        }
2441
2442        data = diffstat_add(diffstat, name_a, name_b);
2443        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2444
2445        if (!one || !two) {
2446                data->is_unmerged = 1;
2447                return;
2448        }
2449
2450        same_contents = !hashcmp(one->sha1, two->sha1);
2451
2452        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2453                data->is_binary = 1;
2454                if (same_contents) {
2455                        data->added = 0;
2456                        data->deleted = 0;
2457                } else {
2458                        data->added = diff_filespec_size(two);
2459                        data->deleted = diff_filespec_size(one);
2460                }
2461        }
2462
2463        else if (complete_rewrite) {
2464                diff_populate_filespec(one, 0);
2465                diff_populate_filespec(two, 0);
2466                data->deleted = count_lines(one->data, one->size);
2467                data->added = count_lines(two->data, two->size);
2468        }
2469
2470        else if (!same_contents) {
2471                /* Crazy xdl interfaces.. */
2472                xpparam_t xpp;
2473                xdemitconf_t xecfg;
2474
2475                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2476                        die("unable to read files to diff");
2477
2478                memset(&xpp, 0, sizeof(xpp));
2479                memset(&xecfg, 0, sizeof(xecfg));
2480                xpp.flags = o->xdl_opts;
2481                xecfg.ctxlen = o->context;
2482                xecfg.interhunkctxlen = o->interhunkcontext;
2483                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2484                                  &xpp, &xecfg))
2485                        die("unable to generate diffstat for %s", one->path);
2486        }
2487
2488        diff_free_filespec_data(one);
2489        diff_free_filespec_data(two);
2490}
2491
2492static void builtin_checkdiff(const char *name_a, const char *name_b,
2493                              const char *attr_path,
2494                              struct diff_filespec *one,
2495                              struct diff_filespec *two,
2496                              struct diff_options *o)
2497{
2498        mmfile_t mf1, mf2;
2499        struct checkdiff_t data;
2500
2501        if (!two)
2502                return;
2503
2504        memset(&data, 0, sizeof(data));
2505        data.filename = name_b ? name_b : name_a;
2506        data.lineno = 0;
2507        data.o = o;
2508        data.ws_rule = whitespace_rule(attr_path);
2509        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2510
2511        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2512                die("unable to read files to diff");
2513
2514        /*
2515         * All the other codepaths check both sides, but not checking
2516         * the "old" side here is deliberate.  We are checking the newly
2517         * introduced changes, and as long as the "new" side is text, we
2518         * can and should check what it introduces.
2519         */
2520        if (diff_filespec_is_binary(two))
2521                goto free_and_return;
2522        else {
2523                /* Crazy xdl interfaces.. */
2524                xpparam_t xpp;
2525                xdemitconf_t xecfg;
2526
2527                memset(&xpp, 0, sizeof(xpp));
2528                memset(&xecfg, 0, sizeof(xecfg));
2529                xecfg.ctxlen = 1; /* at least one context line */
2530                xpp.flags = 0;
2531                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2532                                  &xpp, &xecfg))
2533                        die("unable to generate checkdiff for %s", one->path);
2534
2535                if (data.ws_rule & WS_BLANK_AT_EOF) {
2536                        struct emit_callback ecbdata;
2537                        int blank_at_eof;
2538
2539                        ecbdata.ws_rule = data.ws_rule;
2540                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2541                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2542
2543                        if (blank_at_eof) {
2544                                static char *err;
2545                                if (!err)
2546                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2547                                fprintf(o->file, "%s:%d: %s.\n",
2548                                        data.filename, blank_at_eof, err);
2549                                data.status = 1; /* report errors */
2550                        }
2551                }
2552        }
2553 free_and_return:
2554        diff_free_filespec_data(one);
2555        diff_free_filespec_data(two);
2556        if (data.status)
2557                DIFF_OPT_SET(o, CHECK_FAILED);
2558}
2559
2560struct diff_filespec *alloc_filespec(const char *path)
2561{
2562        int namelen = strlen(path);
2563        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2564
2565        memset(spec, 0, sizeof(*spec));
2566        spec->path = (char *)(spec + 1);
2567        memcpy(spec->path, path, namelen+1);
2568        spec->count = 1;
2569        spec->is_binary = -1;
2570        return spec;
2571}
2572
2573void free_filespec(struct diff_filespec *spec)
2574{
2575        if (!--spec->count) {
2576                diff_free_filespec_data(spec);
2577                free(spec);
2578        }
2579}
2580
2581void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2582                   int sha1_valid, unsigned short mode)
2583{
2584        if (mode) {
2585                spec->mode = canon_mode(mode);
2586                hashcpy(spec->sha1, sha1);
2587                spec->sha1_valid = sha1_valid;
2588        }
2589}
2590
2591/*
2592 * Given a name and sha1 pair, if the index tells us the file in
2593 * the work tree has that object contents, return true, so that
2594 * prepare_temp_file() does not have to inflate and extract.
2595 */
2596static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2597{
2598        const struct cache_entry *ce;
2599        struct stat st;
2600        int pos, len;
2601
2602        /*
2603         * We do not read the cache ourselves here, because the
2604         * benchmark with my previous version that always reads cache
2605         * shows that it makes things worse for diff-tree comparing
2606         * two linux-2.6 kernel trees in an already checked out work
2607         * tree.  This is because most diff-tree comparisons deal with
2608         * only a small number of files, while reading the cache is
2609         * expensive for a large project, and its cost outweighs the
2610         * savings we get by not inflating the object to a temporary
2611         * file.  Practically, this code only helps when we are used
2612         * by diff-cache --cached, which does read the cache before
2613         * calling us.
2614         */
2615        if (!active_cache)
2616                return 0;
2617
2618        /* We want to avoid the working directory if our caller
2619         * doesn't need the data in a normal file, this system
2620         * is rather slow with its stat/open/mmap/close syscalls,
2621         * and the object is contained in a pack file.  The pack
2622         * is probably already open and will be faster to obtain
2623         * the data through than the working directory.  Loose
2624         * objects however would tend to be slower as they need
2625         * to be individually opened and inflated.
2626         */
2627        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2628                return 0;
2629
2630        len = strlen(name);
2631        pos = cache_name_pos(name, len);
2632        if (pos < 0)
2633                return 0;
2634        ce = active_cache[pos];
2635
2636        /*
2637         * This is not the sha1 we are looking for, or
2638         * unreusable because it is not a regular file.
2639         */
2640        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2641                return 0;
2642
2643        /*
2644         * If ce is marked as "assume unchanged", there is no
2645         * guarantee that work tree matches what we are looking for.
2646         */
2647        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2648                return 0;
2649
2650        /*
2651         * If ce matches the file in the work tree, we can reuse it.
2652         */
2653        if (ce_uptodate(ce) ||
2654            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2655                return 1;
2656
2657        return 0;
2658}
2659
2660static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2661{
2662        int len;
2663        char *data = xmalloc(100), *dirty = "";
2664
2665        /* Are we looking at the work tree? */
2666        if (s->dirty_submodule)
2667                dirty = "-dirty";
2668
2669        len = snprintf(data, 100,
2670                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2671        s->data = data;
2672        s->size = len;
2673        s->should_free = 1;
2674        if (size_only) {
2675                s->data = NULL;
2676                free(data);
2677        }
2678        return 0;
2679}
2680
2681/*
2682 * While doing rename detection and pickaxe operation, we may need to
2683 * grab the data for the blob (or file) for our own in-core comparison.
2684 * diff_filespec has data and size fields for this purpose.
2685 */
2686int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2687{
2688        int size_only = flags & CHECK_SIZE_ONLY;
2689        int err = 0;
2690        /*
2691         * demote FAIL to WARN to allow inspecting the situation
2692         * instead of refusing.
2693         */
2694        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2695                                    ? SAFE_CRLF_WARN
2696                                    : safe_crlf);
2697
2698        if (!DIFF_FILE_VALID(s))
2699                die("internal error: asking to populate invalid file.");
2700        if (S_ISDIR(s->mode))
2701                return -1;
2702
2703        if (s->data)
2704                return 0;
2705
2706        if (size_only && 0 < s->size)
2707                return 0;
2708
2709        if (S_ISGITLINK(s->mode))
2710                return diff_populate_gitlink(s, size_only);
2711
2712        if (!s->sha1_valid ||
2713            reuse_worktree_file(s->path, s->sha1, 0)) {
2714                struct strbuf buf = STRBUF_INIT;
2715                struct stat st;
2716                int fd;
2717
2718                if (lstat(s->path, &st) < 0) {
2719                        if (errno == ENOENT) {
2720                        err_empty:
2721                                err = -1;
2722                        empty:
2723                                s->data = (char *)"";
2724                                s->size = 0;
2725                                return err;
2726                        }
2727                }
2728                s->size = xsize_t(st.st_size);
2729                if (!s->size)
2730                        goto empty;
2731                if (S_ISLNK(st.st_mode)) {
2732                        struct strbuf sb = STRBUF_INIT;
2733
2734                        if (strbuf_readlink(&sb, s->path, s->size))
2735                                goto err_empty;
2736                        s->size = sb.len;
2737                        s->data = strbuf_detach(&sb, NULL);
2738                        s->should_free = 1;
2739                        return 0;
2740                }
2741                if (size_only)
2742                        return 0;
2743                if ((flags & CHECK_BINARY) &&
2744                    s->size > big_file_threshold && s->is_binary == -1) {
2745                        s->is_binary = 1;
2746                        return 0;
2747                }
2748                fd = open(s->path, O_RDONLY);
2749                if (fd < 0)
2750                        goto err_empty;
2751                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2752                close(fd);
2753                s->should_munmap = 1;
2754
2755                /*
2756                 * Convert from working tree format to canonical git format
2757                 */
2758                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2759                        size_t size = 0;
2760                        munmap(s->data, s->size);
2761                        s->should_munmap = 0;
2762                        s->data = strbuf_detach(&buf, &size);
2763                        s->size = size;
2764                        s->should_free = 1;
2765                }
2766        }
2767        else {
2768                enum object_type type;
2769                if (size_only || (flags & CHECK_BINARY)) {
2770                        type = sha1_object_info(s->sha1, &s->size);
2771                        if (type < 0)
2772                                die("unable to read %s", sha1_to_hex(s->sha1));
2773                        if (size_only)
2774                                return 0;
2775                        if (s->size > big_file_threshold && s->is_binary == -1) {
2776                                s->is_binary = 1;
2777                                return 0;
2778                        }
2779                }
2780                s->data = read_sha1_file(s->sha1, &type, &s->size);
2781                if (!s->data)
2782                        die("unable to read %s", sha1_to_hex(s->sha1));
2783                s->should_free = 1;
2784        }
2785        return 0;
2786}
2787
2788void diff_free_filespec_blob(struct diff_filespec *s)
2789{
2790        if (s->should_free)
2791                free(s->data);
2792        else if (s->should_munmap)
2793                munmap(s->data, s->size);
2794
2795        if (s->should_free || s->should_munmap) {
2796                s->should_free = s->should_munmap = 0;
2797                s->data = NULL;
2798        }
2799}
2800
2801void diff_free_filespec_data(struct diff_filespec *s)
2802{
2803        diff_free_filespec_blob(s);
2804        free(s->cnt_data);
2805        s->cnt_data = NULL;
2806}
2807
2808static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2809                           void *blob,
2810                           unsigned long size,
2811                           const unsigned char *sha1,
2812                           int mode)
2813{
2814        int fd;
2815        struct strbuf buf = STRBUF_INIT;
2816        struct strbuf template = STRBUF_INIT;
2817        char *path_dup = xstrdup(path);
2818        const char *base = basename(path_dup);
2819
2820        /* Generate "XXXXXX_basename.ext" */
2821        strbuf_addstr(&template, "XXXXXX_");
2822        strbuf_addstr(&template, base);
2823
2824        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2825                        strlen(base) + 1);
2826        if (fd < 0)
2827                die_errno("unable to create temp-file");
2828        if (convert_to_working_tree(path,
2829                        (const char *)blob, (size_t)size, &buf)) {
2830                blob = buf.buf;
2831                size = buf.len;
2832        }
2833        if (write_in_full(fd, blob, size) != size)
2834                die_errno("unable to write temp-file");
2835        close(fd);
2836        temp->name = temp->tmp_path;
2837        strcpy(temp->hex, sha1_to_hex(sha1));
2838        temp->hex[40] = 0;
2839        sprintf(temp->mode, "%06o", mode);
2840        strbuf_release(&buf);
2841        strbuf_release(&template);
2842        free(path_dup);
2843}
2844
2845static struct diff_tempfile *prepare_temp_file(const char *name,
2846                struct diff_filespec *one)
2847{
2848        struct diff_tempfile *temp = claim_diff_tempfile();
2849
2850        if (!DIFF_FILE_VALID(one)) {
2851        not_a_valid_file:
2852                /* A '-' entry produces this for file-2, and
2853                 * a '+' entry produces this for file-1.
2854                 */
2855                temp->name = "/dev/null";
2856                strcpy(temp->hex, ".");
2857                strcpy(temp->mode, ".");
2858                return temp;
2859        }
2860
2861        if (!remove_tempfile_installed) {
2862                atexit(remove_tempfile);
2863                sigchain_push_common(remove_tempfile_on_signal);
2864                remove_tempfile_installed = 1;
2865        }
2866
2867        if (!S_ISGITLINK(one->mode) &&
2868            (!one->sha1_valid ||
2869             reuse_worktree_file(name, one->sha1, 1))) {
2870                struct stat st;
2871                if (lstat(name, &st) < 0) {
2872                        if (errno == ENOENT)
2873                                goto not_a_valid_file;
2874                        die_errno("stat(%s)", name);
2875                }
2876                if (S_ISLNK(st.st_mode)) {
2877                        struct strbuf sb = STRBUF_INIT;
2878                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2879                                die_errno("readlink(%s)", name);
2880                        prep_temp_blob(name, temp, sb.buf, sb.len,
2881                                       (one->sha1_valid ?
2882                                        one->sha1 : null_sha1),
2883                                       (one->sha1_valid ?
2884                                        one->mode : S_IFLNK));
2885                        strbuf_release(&sb);
2886                }
2887                else {
2888                        /* we can borrow from the file in the work tree */
2889                        temp->name = name;
2890                        if (!one->sha1_valid)
2891                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2892                        else
2893                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2894                        /* Even though we may sometimes borrow the
2895                         * contents from the work tree, we always want
2896                         * one->mode.  mode is trustworthy even when
2897                         * !(one->sha1_valid), as long as
2898                         * DIFF_FILE_VALID(one).
2899                         */
2900                        sprintf(temp->mode, "%06o", one->mode);
2901                }
2902                return temp;
2903        }
2904        else {
2905                if (diff_populate_filespec(one, 0))
2906                        die("cannot read data blob for %s", one->path);
2907                prep_temp_blob(name, temp, one->data, one->size,
2908                               one->sha1, one->mode);
2909        }
2910        return temp;
2911}
2912
2913static void add_external_diff_name(struct argv_array *argv,
2914                                   const char *name,
2915                                   struct diff_filespec *df)
2916{
2917        struct diff_tempfile *temp = prepare_temp_file(name, df);
2918        argv_array_push(argv, temp->name);
2919        argv_array_push(argv, temp->hex);
2920        argv_array_push(argv, temp->mode);
2921}
2922
2923/* An external diff command takes:
2924 *
2925 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2926 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2927 *
2928 */
2929static void run_external_diff(const char *pgm,
2930                              const char *name,
2931                              const char *other,
2932                              struct diff_filespec *one,
2933                              struct diff_filespec *two,
2934                              const char *xfrm_msg,
2935                              int complete_rewrite,
2936                              struct diff_options *o)
2937{
2938        struct argv_array argv = ARGV_ARRAY_INIT;
2939        struct argv_array env = ARGV_ARRAY_INIT;
2940        struct diff_queue_struct *q = &diff_queued_diff;
2941
2942        argv_array_push(&argv, pgm);
2943        argv_array_push(&argv, name);
2944
2945        if (one && two) {
2946                add_external_diff_name(&argv, name, one);
2947                if (!other)
2948                        add_external_diff_name(&argv, name, two);
2949                else {
2950                        add_external_diff_name(&argv, other, two);
2951                        argv_array_push(&argv, other);
2952                        argv_array_push(&argv, xfrm_msg);
2953                }
2954        }
2955
2956        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2957        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2958
2959        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2960                die(_("external diff died, stopping at %s"), name);
2961
2962        remove_tempfile();
2963        argv_array_clear(&argv);
2964        argv_array_clear(&env);
2965}
2966
2967static int similarity_index(struct diff_filepair *p)
2968{
2969        return p->score * 100 / MAX_SCORE;
2970}
2971
2972static void fill_metainfo(struct strbuf *msg,
2973                          const char *name,
2974                          const char *other,
2975                          struct diff_filespec *one,
2976                          struct diff_filespec *two,
2977                          struct diff_options *o,
2978                          struct diff_filepair *p,
2979                          int *must_show_header,
2980                          int use_color)
2981{
2982        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2983        const char *reset = diff_get_color(use_color, DIFF_RESET);
2984        const char *line_prefix = diff_line_prefix(o);
2985
2986        *must_show_header = 1;
2987        strbuf_init(msg, PATH_MAX * 2 + 300);
2988        switch (p->status) {
2989        case DIFF_STATUS_COPIED:
2990                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2991                            line_prefix, set, similarity_index(p));
2992                strbuf_addf(msg, "%s\n%s%scopy from ",
2993                            reset,  line_prefix, set);
2994                quote_c_style(name, msg, NULL, 0);
2995                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2996                quote_c_style(other, msg, NULL, 0);
2997                strbuf_addf(msg, "%s\n", reset);
2998                break;
2999        case DIFF_STATUS_RENAMED:
3000                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3001                            line_prefix, set, similarity_index(p));
3002                strbuf_addf(msg, "%s\n%s%srename from ",
3003                            reset, line_prefix, set);
3004                quote_c_style(name, msg, NULL, 0);
3005                strbuf_addf(msg, "%s\n%s%srename to ",
3006                            reset, line_prefix, set);
3007                quote_c_style(other, msg, NULL, 0);
3008                strbuf_addf(msg, "%s\n", reset);
3009                break;
3010        case DIFF_STATUS_MODIFIED:
3011                if (p->score) {
3012                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3013                                    line_prefix,
3014                                    set, similarity_index(p), reset);
3015                        break;
3016                }
3017                /* fallthru */
3018        default:
3019                *must_show_header = 0;
3020        }
3021        if (one && two && hashcmp(one->sha1, two->sha1)) {
3022                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3023
3024                if (DIFF_OPT_TST(o, BINARY)) {
3025                        mmfile_t mf;
3026                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3027                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3028                                abbrev = 40;
3029                }
3030                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3031                            find_unique_abbrev(one->sha1, abbrev));
3032                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3033                if (one->mode == two->mode)
3034                        strbuf_addf(msg, " %06o", one->mode);
3035                strbuf_addf(msg, "%s\n", reset);
3036        }
3037}
3038
3039static void run_diff_cmd(const char *pgm,
3040                         const char *name,
3041                         const char *other,
3042                         const char *attr_path,
3043                         struct diff_filespec *one,
3044                         struct diff_filespec *two,
3045                         struct strbuf *msg,
3046                         struct diff_options *o,
3047                         struct diff_filepair *p)
3048{
3049        const char *xfrm_msg = NULL;
3050        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3051        int must_show_header = 0;
3052
3053
3054        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3055                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3056                if (drv && drv->external)
3057                        pgm = drv->external;
3058        }
3059
3060        if (msg) {
3061                /*
3062                 * don't use colors when the header is intended for an
3063                 * external diff driver
3064                 */
3065                fill_metainfo(msg, name, other, one, two, o, p,
3066                              &must_show_header,
3067                              want_color(o->use_color) && !pgm);
3068                xfrm_msg = msg->len ? msg->buf : NULL;
3069        }
3070
3071        if (pgm) {
3072                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3073                                  complete_rewrite, o);
3074                return;
3075        }
3076        if (one && two)
3077                builtin_diff(name, other ? other : name,
3078                             one, two, xfrm_msg, must_show_header,
3079                             o, complete_rewrite);
3080        else
3081                fprintf(o->file, "* Unmerged path %s\n", name);
3082}
3083
3084static void diff_fill_sha1_info(struct diff_filespec *one)
3085{
3086        if (DIFF_FILE_VALID(one)) {
3087                if (!one->sha1_valid) {
3088                        struct stat st;
3089                        if (one->is_stdin) {
3090                                hashcpy(one->sha1, null_sha1);
3091                                return;
3092                        }
3093                        if (lstat(one->path, &st) < 0)
3094                                die_errno("stat '%s'", one->path);
3095                        if (index_path(one->sha1, one->path, &st, 0))
3096                                die("cannot hash %s", one->path);
3097                }
3098        }
3099        else
3100                hashclr(one->sha1);
3101}
3102
3103static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3104{
3105        /* Strip the prefix but do not molest /dev/null and absolute paths */
3106        if (*namep && **namep != '/') {
3107                *namep += prefix_length;
3108                if (**namep == '/')
3109                        ++*namep;
3110        }
3111        if (*otherp && **otherp != '/') {
3112                *otherp += prefix_length;
3113                if (**otherp == '/')
3114                        ++*otherp;
3115        }
3116}
3117
3118static void run_diff(struct diff_filepair *p, struct diff_options *o)
3119{
3120        const char *pgm = external_diff();
3121        struct strbuf msg;
3122        struct diff_filespec *one = p->one;
3123        struct diff_filespec *two = p->two;
3124        const char *name;
3125        const char *other;
3126        const char *attr_path;
3127
3128        name  = p->one->path;
3129        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3130        attr_path = name;
3131        if (o->prefix_length)
3132                strip_prefix(o->prefix_length, &name, &other);
3133
3134        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3135                pgm = NULL;
3136
3137        if (DIFF_PAIR_UNMERGED(p)) {
3138                run_diff_cmd(pgm, name, NULL, attr_path,
3139                             NULL, NULL, NULL, o, p);
3140                return;
3141        }
3142
3143        diff_fill_sha1_info(one);
3144        diff_fill_sha1_info(two);
3145
3146        if (!pgm &&
3147            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3148            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3149                /*
3150                 * a filepair that changes between file and symlink
3151                 * needs to be split into deletion and creation.
3152                 */
3153                struct diff_filespec *null = alloc_filespec(two->path);
3154                run_diff_cmd(NULL, name, other, attr_path,
3155                             one, null, &msg, o, p);
3156                free(null);
3157                strbuf_release(&msg);
3158
3159                null = alloc_filespec(one->path);
3160                run_diff_cmd(NULL, name, other, attr_path,
3161                             null, two, &msg, o, p);
3162                free(null);
3163        }
3164        else
3165                run_diff_cmd(pgm, name, other, attr_path,
3166                             one, two, &msg, o, p);
3167
3168        strbuf_release(&msg);
3169}
3170
3171static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3172                         struct diffstat_t *diffstat)
3173{
3174        const char *name;
3175        const char *other;
3176
3177        if (DIFF_PAIR_UNMERGED(p)) {
3178                /* unmerged */
3179                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3180                return;
3181        }
3182
3183        name = p->one->path;
3184        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3185
3186        if (o->prefix_length)
3187                strip_prefix(o->prefix_length, &name, &other);
3188
3189        diff_fill_sha1_info(p->one);
3190        diff_fill_sha1_info(p->two);
3191
3192        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3193}
3194
3195static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3196{
3197        const char *name;
3198        const char *other;
3199        const char *attr_path;
3200
3201        if (DIFF_PAIR_UNMERGED(p)) {
3202                /* unmerged */
3203                return;
3204        }
3205
3206        name = p->one->path;
3207        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3208        attr_path = other ? other : name;
3209
3210        if (o->prefix_length)
3211                strip_prefix(o->prefix_length, &name, &other);
3212
3213        diff_fill_sha1_info(p->one);
3214        diff_fill_sha1_info(p->two);
3215
3216        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3217}
3218
3219void diff_setup(struct diff_options *options)
3220{
3221        memcpy(options, &default_diff_options, sizeof(*options));
3222
3223        options->file = stdout;
3224
3225        options->line_termination = '\n';
3226        options->break_opt = -1;
3227        options->rename_limit = -1;
3228        options->dirstat_permille = diff_dirstat_permille_default;
3229        options->context = diff_context_default;
3230        DIFF_OPT_SET(options, RENAME_EMPTY);
3231
3232        /* pathchange left =NULL by default */
3233        options->change = diff_change;
3234        options->add_remove = diff_addremove;
3235        options->use_color = diff_use_color_default;
3236        options->detect_rename = diff_detect_rename_default;
3237        options->xdl_opts |= diff_algorithm;
3238
3239        options->orderfile = diff_order_file_cfg;
3240
3241        if (diff_no_prefix) {
3242                options->a_prefix = options->b_prefix = "";
3243        } else if (!diff_mnemonic_prefix) {
3244                options->a_prefix = "a/";
3245                options->b_prefix = "b/";
3246        }
3247}
3248
3249void diff_setup_done(struct diff_options *options)
3250{
3251        int count = 0;
3252
3253        if (options->set_default)
3254                options->set_default(options);
3255
3256        if (options->output_format & DIFF_FORMAT_NAME)
3257                count++;
3258        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3259                count++;
3260        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3261                count++;
3262        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3263                count++;
3264        if (count > 1)
3265                die("--name-only, --name-status, --check and -s are mutually exclusive");
3266
3267        /*
3268         * Most of the time we can say "there are changes"
3269         * only by checking if there are changed paths, but
3270         * --ignore-whitespace* options force us to look
3271         * inside contents.
3272         */
3273
3274        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3275            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3276            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3277                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3278        else
3279                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3280
3281        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3282                options->detect_rename = DIFF_DETECT_COPY;
3283
3284        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3285                options->prefix = NULL;
3286        if (options->prefix)
3287                options->prefix_length = strlen(options->prefix);
3288        else
3289                options->prefix_length = 0;
3290
3291        if (options->output_format & (DIFF_FORMAT_NAME |
3292                                      DIFF_FORMAT_NAME_STATUS |
3293                                      DIFF_FORMAT_CHECKDIFF |
3294                                      DIFF_FORMAT_NO_OUTPUT))
3295                options->output_format &= ~(DIFF_FORMAT_RAW |
3296                                            DIFF_FORMAT_NUMSTAT |
3297                                            DIFF_FORMAT_DIFFSTAT |
3298                                            DIFF_FORMAT_SHORTSTAT |
3299                                            DIFF_FORMAT_DIRSTAT |
3300                                            DIFF_FORMAT_SUMMARY |
3301                                            DIFF_FORMAT_PATCH);
3302
3303        /*
3304         * These cases always need recursive; we do not drop caller-supplied
3305         * recursive bits for other formats here.
3306         */
3307        if (options->output_format & (DIFF_FORMAT_PATCH |
3308                                      DIFF_FORMAT_NUMSTAT |
3309                                      DIFF_FORMAT_DIFFSTAT |
3310                                      DIFF_FORMAT_SHORTSTAT |
3311                                      DIFF_FORMAT_DIRSTAT |
3312                                      DIFF_FORMAT_SUMMARY |
3313                                      DIFF_FORMAT_CHECKDIFF))
3314                DIFF_OPT_SET(options, RECURSIVE);
3315        /*
3316         * Also pickaxe would not work very well if you do not say recursive
3317         */
3318        if (options->pickaxe)
3319                DIFF_OPT_SET(options, RECURSIVE);
3320        /*
3321         * When patches are generated, submodules diffed against the work tree
3322         * must be checked for dirtiness too so it can be shown in the output
3323         */
3324        if (options->output_format & DIFF_FORMAT_PATCH)
3325                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3326
3327        if (options->detect_rename && options->rename_limit < 0)
3328                options->rename_limit = diff_rename_limit_default;
3329        if (options->setup & DIFF_SETUP_USE_CACHE) {
3330                if (!active_cache)
3331                        /* read-cache does not die even when it fails
3332                         * so it is safe for us to do this here.  Also
3333                         * it does not smudge active_cache or active_nr
3334                         * when it fails, so we do not have to worry about
3335                         * cleaning it up ourselves either.
3336                         */
3337                        read_cache();
3338        }
3339        if (options->abbrev <= 0 || 40 < options->abbrev)
3340                options->abbrev = 40; /* full */
3341
3342        /*
3343         * It does not make sense to show the first hit we happened
3344         * to have found.  It does not make sense not to return with
3345         * exit code in such a case either.
3346         */
3347        if (DIFF_OPT_TST(options, QUICK)) {
3348                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3349                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3350        }
3351
3352        options->diff_path_counter = 0;
3353
3354        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3355                die(_("--follow requires exactly one pathspec"));
3356}
3357
3358static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3359{
3360        char c, *eq;
3361        int len;
3362
3363        if (*arg != '-')
3364                return 0;
3365        c = *++arg;
3366        if (!c)
3367                return 0;
3368        if (c == arg_short) {
3369                c = *++arg;
3370                if (!c)
3371                        return 1;
3372                if (val && isdigit(c)) {
3373                        char *end;
3374                        int n = strtoul(arg, &end, 10);
3375                        if (*end)
3376                                return 0;
3377                        *val = n;
3378                        return 1;
3379                }
3380                return 0;
3381        }
3382        if (c != '-')
3383                return 0;
3384        arg++;
3385        eq = strchrnul(arg, '=');
3386        len = eq - arg;
3387        if (!len || strncmp(arg, arg_long, len))
3388                return 0;
3389        if (*eq) {
3390                int n;
3391                char *end;
3392                if (!isdigit(*++eq))
3393                        return 0;
3394                n = strtoul(eq, &end, 10);
3395                if (*end)
3396                        return 0;
3397                *val = n;
3398        }
3399        return 1;
3400}
3401
3402static int diff_scoreopt_parse(const char *opt);
3403
3404static inline int short_opt(char opt, const char **argv,
3405                            const char **optarg)
3406{
3407        const char *arg = argv[0];
3408        if (arg[0] != '-' || arg[1] != opt)
3409                return 0;
3410        if (arg[2] != '\0') {
3411                *optarg = arg + 2;
3412                return 1;
3413        }
3414        if (!argv[1])
3415                die("Option '%c' requires a value", opt);
3416        *optarg = argv[1];
3417        return 2;
3418}
3419
3420int parse_long_opt(const char *opt, const char **argv,
3421                   const char **optarg)
3422{
3423        const char *arg = argv[0];
3424        if (!skip_prefix(arg, "--", &arg))
3425                return 0;
3426        if (!skip_prefix(arg, opt, &arg))
3427                return 0;
3428        if (*arg == '=') { /* stuck form: --option=value */
3429                *optarg = arg + 1;
3430                return 1;
3431        }
3432        if (*arg != '\0')
3433                return 0;
3434        /* separate form: --option value */
3435        if (!argv[1])
3436                die("Option '--%s' requires a value", opt);
3437        *optarg = argv[1];
3438        return 2;
3439}
3440
3441static int stat_opt(struct diff_options *options, const char **av)
3442{
3443        const char *arg = av[0];
3444        char *end;
3445        int width = options->stat_width;
3446        int name_width = options->stat_name_width;
3447        int graph_width = options->stat_graph_width;
3448        int count = options->stat_count;
3449        int argcount = 1;
3450
3451        if (!skip_prefix(arg, "--stat", &arg))
3452                die("BUG: stat option does not begin with --stat: %s", arg);
3453        end = (char *)arg;
3454
3455        switch (*arg) {
3456        case '-':
3457                if (skip_prefix(arg, "-width", &arg)) {
3458                        if (*arg == '=')
3459                                width = strtoul(arg + 1, &end, 10);
3460                        else if (!*arg && !av[1])
3461                                die("Option '--stat-width' requires a value");
3462                        else if (!*arg) {
3463                                width = strtoul(av[1], &end, 10);
3464                                argcount = 2;
3465                        }
3466                } else if (skip_prefix(arg, "-name-width", &arg)) {
3467                        if (*arg == '=')
3468                                name_width = strtoul(arg + 1, &end, 10);
3469                        else if (!*arg && !av[1])
3470                                die("Option '--stat-name-width' requires a value");
3471                        else if (!*arg) {
3472                                name_width = strtoul(av[1], &end, 10);
3473                                argcount = 2;
3474                        }
3475                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3476                        if (*arg == '=')
3477                                graph_width = strtoul(arg + 1, &end, 10);
3478                        else if (!*arg && !av[1])
3479                                die("Option '--stat-graph-width' requires a value");
3480                        else if (!*arg) {
3481                                graph_width = strtoul(av[1], &end, 10);
3482                                argcount = 2;
3483                        }
3484                } else if (skip_prefix(arg, "-count", &arg)) {
3485                        if (*arg == '=')
3486                                count = strtoul(arg + 1, &end, 10);
3487                        else if (!*arg && !av[1])
3488                                die("Option '--stat-count' requires a value");
3489                        else if (!*arg) {
3490                                count = strtoul(av[1], &end, 10);
3491                                argcount = 2;
3492                        }
3493                }
3494                break;
3495        case '=':
3496                width = strtoul(arg+1, &end, 10);
3497                if (*end == ',')
3498                        name_width = strtoul(end+1, &end, 10);
3499                if (*end == ',')
3500                        count = strtoul(end+1, &end, 10);
3501        }
3502
3503        /* Important! This checks all the error cases! */
3504        if (*end)
3505                return 0;
3506        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3507        options->stat_name_width = name_width;
3508        options->stat_graph_width = graph_width;
3509        options->stat_width = width;
3510        options->stat_count = count;
3511        return argcount;
3512}
3513
3514static int parse_dirstat_opt(struct diff_options *options, const char *params)
3515{
3516        struct strbuf errmsg = STRBUF_INIT;
3517        if (parse_dirstat_params(options, params, &errmsg))
3518                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3519                    errmsg.buf);
3520        strbuf_release(&errmsg);
3521        /*
3522         * The caller knows a dirstat-related option is given from the command
3523         * line; allow it to say "return this_function();"
3524         */
3525        options->output_format |= DIFF_FORMAT_DIRSTAT;
3526        return 1;
3527}
3528
3529static int parse_submodule_opt(struct diff_options *options, const char *value)
3530{
3531        if (parse_submodule_params(options, value))
3532                die(_("Failed to parse --submodule option parameter: '%s'"),
3533                        value);
3534        return 1;
3535}
3536
3537static const char diff_status_letters[] = {
3538        DIFF_STATUS_ADDED,
3539        DIFF_STATUS_COPIED,
3540        DIFF_STATUS_DELETED,
3541        DIFF_STATUS_MODIFIED,
3542        DIFF_STATUS_RENAMED,
3543        DIFF_STATUS_TYPE_CHANGED,
3544        DIFF_STATUS_UNKNOWN,
3545        DIFF_STATUS_UNMERGED,
3546        DIFF_STATUS_FILTER_AON,
3547        DIFF_STATUS_FILTER_BROKEN,
3548        '\0',
3549};
3550
3551static unsigned int filter_bit['Z' + 1];
3552
3553static void prepare_filter_bits(void)
3554{
3555        int i;
3556
3557        if (!filter_bit[DIFF_STATUS_ADDED]) {
3558                for (i = 0; diff_status_letters[i]; i++)
3559                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3560        }
3561}
3562
3563static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3564{
3565        return opt->filter & filter_bit[(int) status];
3566}
3567
3568static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3569{
3570        int i, optch;
3571
3572        prepare_filter_bits();
3573
3574        /*
3575         * If there is a negation e.g. 'd' in the input, and we haven't
3576         * initialized the filter field with another --diff-filter, start
3577         * from full set of bits, except for AON.
3578         */
3579        if (!opt->filter) {
3580                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3581                        if (optch < 'a' || 'z' < optch)
3582                                continue;
3583                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3584                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3585                        break;
3586                }
3587        }
3588
3589        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3590                unsigned int bit;
3591                int negate;
3592
3593                if ('a' <= optch && optch <= 'z') {
3594                        negate = 1;
3595                        optch = toupper(optch);
3596                } else {
3597                        negate = 0;
3598                }
3599
3600                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3601                if (!bit)
3602                        return optarg[i];
3603                if (negate)
3604                        opt->filter &= ~bit;
3605                else
3606                        opt->filter |= bit;
3607        }
3608        return 0;
3609}
3610
3611static void enable_patch_output(int *fmt) {
3612        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3613        *fmt |= DIFF_FORMAT_PATCH;
3614}
3615
3616int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3617{
3618        const char *arg = av[0];
3619        const char *optarg;
3620        int argcount;
3621
3622        /* Output format options */
3623        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3624            || opt_arg(arg, 'U', "unified", &options->context))
3625                enable_patch_output(&options->output_format);
3626        else if (!strcmp(arg, "--raw"))
3627                options->output_format |= DIFF_FORMAT_RAW;
3628        else if (!strcmp(arg, "--patch-with-raw")) {
3629                enable_patch_output(&options->output_format);
3630                options->output_format |= DIFF_FORMAT_RAW;
3631        } else if (!strcmp(arg, "--numstat"))
3632                options->output_format |= DIFF_FORMAT_NUMSTAT;
3633        else if (!strcmp(arg, "--shortstat"))
3634                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3635        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3636                return parse_dirstat_opt(options, "");
3637        else if (skip_prefix(arg, "-X", &arg))
3638                return parse_dirstat_opt(options, arg);
3639        else if (skip_prefix(arg, "--dirstat=", &arg))
3640                return parse_dirstat_opt(options, arg);
3641        else if (!strcmp(arg, "--cumulative"))
3642                return parse_dirstat_opt(options, "cumulative");
3643        else if (!strcmp(arg, "--dirstat-by-file"))
3644                return parse_dirstat_opt(options, "files");
3645        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3646                parse_dirstat_opt(options, "files");
3647                return parse_dirstat_opt(options, arg);
3648        }
3649        else if (!strcmp(arg, "--check"))
3650                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3651        else if (!strcmp(arg, "--summary"))
3652                options->output_format |= DIFF_FORMAT_SUMMARY;
3653        else if (!strcmp(arg, "--patch-with-stat")) {
3654                enable_patch_output(&options->output_format);
3655                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3656        } else if (!strcmp(arg, "--name-only"))
3657                options->output_format |= DIFF_FORMAT_NAME;
3658        else if (!strcmp(arg, "--name-status"))
3659                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3660        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3661                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3662        else if (starts_with(arg, "--stat"))
3663                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3664                return stat_opt(options, av);
3665
3666        /* renames options */
3667        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3668                 !strcmp(arg, "--break-rewrites")) {
3669                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3670                        return error("invalid argument to -B: %s", arg+2);
3671        }
3672        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3673                 !strcmp(arg, "--find-renames")) {
3674                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3675                        return error("invalid argument to -M: %s", arg+2);
3676                options->detect_rename = DIFF_DETECT_RENAME;
3677        }
3678        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3679                options->irreversible_delete = 1;
3680        }
3681        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3682                 !strcmp(arg, "--find-copies")) {
3683                if (options->detect_rename == DIFF_DETECT_COPY)
3684                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3685                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3686                        return error("invalid argument to -C: %s", arg+2);
3687                options->detect_rename = DIFF_DETECT_COPY;
3688        }
3689        else if (!strcmp(arg, "--no-renames"))
3690                options->detect_rename = 0;
3691        else if (!strcmp(arg, "--rename-empty"))
3692                DIFF_OPT_SET(options, RENAME_EMPTY);
3693        else if (!strcmp(arg, "--no-rename-empty"))
3694                DIFF_OPT_CLR(options, RENAME_EMPTY);
3695        else if (!strcmp(arg, "--relative"))
3696                DIFF_OPT_SET(options, RELATIVE_NAME);
3697        else if (skip_prefix(arg, "--relative=", &arg)) {
3698                DIFF_OPT_SET(options, RELATIVE_NAME);
3699                options->prefix = arg;
3700        }
3701
3702        /* xdiff options */
3703        else if (!strcmp(arg, "--minimal"))
3704                DIFF_XDL_SET(options, NEED_MINIMAL);
3705        else if (!strcmp(arg, "--no-minimal"))
3706                DIFF_XDL_CLR(options, NEED_MINIMAL);
3707        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3708                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3709        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3710                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3711        else if (!strcmp(arg, "--ignore-space-at-eol"))
3712                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3713        else if (!strcmp(arg, "--ignore-blank-lines"))
3714                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3715        else if (!strcmp(arg, "--patience"))
3716                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3717        else if (!strcmp(arg, "--histogram"))
3718                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3719        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3720                long value = parse_algorithm_value(optarg);
3721                if (value < 0)
3722                        return error("option diff-algorithm accepts \"myers\", "
3723                                     "\"minimal\", \"patience\" and \"histogram\"");
3724                /* clear out previous settings */
3725                DIFF_XDL_CLR(options, NEED_MINIMAL);
3726                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3727                options->xdl_opts |= value;
3728                return argcount;
3729        }
3730
3731        /* flags options */
3732        else if (!strcmp(arg, "--binary")) {
3733                enable_patch_output(&options->output_format);
3734                DIFF_OPT_SET(options, BINARY);
3735        }
3736        else if (!strcmp(arg, "--full-index"))
3737                DIFF_OPT_SET(options, FULL_INDEX);
3738        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3739                DIFF_OPT_SET(options, TEXT);
3740        else if (!strcmp(arg, "-R"))
3741                DIFF_OPT_SET(options, REVERSE_DIFF);
3742        else if (!strcmp(arg, "--find-copies-harder"))
3743                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3744        else if (!strcmp(arg, "--follow"))
3745                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3746        else if (!strcmp(arg, "--no-follow"))
3747                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3748        else if (!strcmp(arg, "--color"))
3749                options->use_color = 1;
3750        else if (skip_prefix(arg, "--color=", &arg)) {
3751                int value = git_config_colorbool(NULL, arg);
3752                if (value < 0)
3753                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3754                options->use_color = value;
3755        }
3756        else if (!strcmp(arg, "--no-color"))
3757                options->use_color = 0;
3758        else if (!strcmp(arg, "--color-words")) {
3759                options->use_color = 1;
3760                options->word_diff = DIFF_WORDS_COLOR;
3761        }
3762        else if (skip_prefix(arg, "--color-words=", &arg)) {
3763                options->use_color = 1;
3764                options->word_diff = DIFF_WORDS_COLOR;
3765                options->word_regex = arg;
3766        }
3767        else if (!strcmp(arg, "--word-diff")) {
3768                if (options->word_diff == DIFF_WORDS_NONE)
3769                        options->word_diff = DIFF_WORDS_PLAIN;
3770        }
3771        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3772                if (!strcmp(arg, "plain"))
3773                        options->word_diff = DIFF_WORDS_PLAIN;
3774                else if (!strcmp(arg, "color")) {
3775                        options->use_color = 1;
3776                        options->word_diff = DIFF_WORDS_COLOR;
3777                }
3778                else if (!strcmp(arg, "porcelain"))
3779                        options->word_diff = DIFF_WORDS_PORCELAIN;
3780                else if (!strcmp(arg, "none"))
3781                        options->word_diff = DIFF_WORDS_NONE;
3782                else
3783                        die("bad --word-diff argument: %s", arg);
3784        }
3785        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3786                if (options->word_diff == DIFF_WORDS_NONE)
3787                        options->word_diff = DIFF_WORDS_PLAIN;
3788                options->word_regex = optarg;
3789                return argcount;
3790        }
3791        else if (!strcmp(arg, "--exit-code"))
3792                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3793        else if (!strcmp(arg, "--quiet"))
3794                DIFF_OPT_SET(options, QUICK);
3795        else if (!strcmp(arg, "--ext-diff"))
3796                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3797        else if (!strcmp(arg, "--no-ext-diff"))
3798                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3799        else if (!strcmp(arg, "--textconv"))
3800                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3801        else if (!strcmp(arg, "--no-textconv"))
3802                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3803        else if (!strcmp(arg, "--ignore-submodules")) {
3804                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3805                handle_ignore_submodules_arg(options, "all");
3806        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3807                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3808                handle_ignore_submodules_arg(options, arg);
3809        } else if (!strcmp(arg, "--submodule"))
3810                DIFF_OPT_SET(options, SUBMODULE_LOG);
3811        else if (skip_prefix(arg, "--submodule=", &arg))
3812                return parse_submodule_opt(options, arg);
3813
3814        /* misc options */
3815        else if (!strcmp(arg, "-z"))
3816                options->line_termination = 0;
3817        else if ((argcount = short_opt('l', av, &optarg))) {
3818                options->rename_limit = strtoul(optarg, NULL, 10);
3819                return argcount;
3820        }
3821        else if ((argcount = short_opt('S', av, &optarg))) {
3822                options->pickaxe = optarg;
3823                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3824                return argcount;
3825        } else if ((argcount = short_opt('G', av, &optarg))) {
3826                options->pickaxe = optarg;
3827                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3828                return argcount;
3829        }
3830        else if (!strcmp(arg, "--pickaxe-all"))
3831                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3832        else if (!strcmp(arg, "--pickaxe-regex"))
3833                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3834        else if ((argcount = short_opt('O', av, &optarg))) {
3835                options->orderfile = optarg;
3836                return argcount;
3837        }
3838        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3839                int offending = parse_diff_filter_opt(optarg, options);
3840                if (offending)
3841                        die("unknown change class '%c' in --diff-filter=%s",
3842                            offending, optarg);
3843                return argcount;
3844        }
3845        else if (!strcmp(arg, "--abbrev"))
3846                options->abbrev = DEFAULT_ABBREV;
3847        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3848                options->abbrev = strtoul(arg, NULL, 10);
3849                if (options->abbrev < MINIMUM_ABBREV)
3850                        options->abbrev = MINIMUM_ABBREV;
3851                else if (40 < options->abbrev)
3852                        options->abbrev = 40;
3853        }
3854        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3855                options->a_prefix = optarg;
3856                return argcount;
3857        }
3858        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3859                options->b_prefix = optarg;
3860                return argcount;
3861        }
3862        else if (!strcmp(arg, "--no-prefix"))
3863                options->a_prefix = options->b_prefix = "";
3864        else if (opt_arg(arg, '\0', "inter-hunk-context",
3865                         &options->interhunkcontext))
3866                ;
3867        else if (!strcmp(arg, "-W"))
3868                DIFF_OPT_SET(options, FUNCCONTEXT);
3869        else if (!strcmp(arg, "--function-context"))
3870                DIFF_OPT_SET(options, FUNCCONTEXT);
3871        else if (!strcmp(arg, "--no-function-context"))
3872                DIFF_OPT_CLR(options, FUNCCONTEXT);
3873        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3874                options->file = fopen(optarg, "w");
3875                if (!options->file)
3876                        die_errno("Could not open '%s'", optarg);
3877                options->close_file = 1;
3878                return argcount;
3879        } else
3880                return 0;
3881        return 1;
3882}
3883
3884int parse_rename_score(const char **cp_p)
3885{
3886        unsigned long num, scale;
3887        int ch, dot;
3888        const char *cp = *cp_p;
3889
3890        num = 0;
3891        scale = 1;
3892        dot = 0;
3893        for (;;) {
3894                ch = *cp;
3895                if ( !dot && ch == '.' ) {
3896                        scale = 1;
3897                        dot = 1;
3898                } else if ( ch == '%' ) {
3899                        scale = dot ? scale*100 : 100;
3900                        cp++;   /* % is always at the end */
3901                        break;
3902                } else if ( ch >= '0' && ch <= '9' ) {
3903                        if ( scale < 100000 ) {
3904                                scale *= 10;
3905                                num = (num*10) + (ch-'0');
3906                        }
3907                } else {
3908                        break;
3909                }
3910                cp++;
3911        }
3912        *cp_p = cp;
3913
3914        /* user says num divided by scale and we say internally that
3915         * is MAX_SCORE * num / scale.
3916         */
3917        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3918}
3919
3920static int diff_scoreopt_parse(const char *opt)
3921{
3922        int opt1, opt2, cmd;
3923
3924        if (*opt++ != '-')
3925                return -1;
3926        cmd = *opt++;
3927        if (cmd == '-') {
3928                /* convert the long-form arguments into short-form versions */
3929                if (skip_prefix(opt, "break-rewrites", &opt)) {
3930                        if (*opt == 0 || *opt++ == '=')
3931                                cmd = 'B';
3932                } else if (skip_prefix(opt, "find-copies", &opt)) {
3933                        if (*opt == 0 || *opt++ == '=')
3934                                cmd = 'C';
3935                } else if (skip_prefix(opt, "find-renames", &opt)) {
3936                        if (*opt == 0 || *opt++ == '=')
3937                                cmd = 'M';
3938                }
3939        }
3940        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3941                return -1; /* that is not a -M, -C, or -B option */
3942
3943        opt1 = parse_rename_score(&opt);
3944        if (cmd != 'B')
3945                opt2 = 0;
3946        else {
3947                if (*opt == 0)
3948                        opt2 = 0;
3949                else if (*opt != '/')
3950                        return -1; /* we expect -B80/99 or -B80 */
3951                else {
3952                        opt++;
3953                        opt2 = parse_rename_score(&opt);
3954                }
3955        }
3956        if (*opt != 0)
3957                return -1;
3958        return opt1 | (opt2 << 16);
3959}
3960
3961struct diff_queue_struct diff_queued_diff;
3962
3963void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3964{
3965        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
3966        queue->queue[queue->nr++] = dp;
3967}
3968
3969struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3970                                 struct diff_filespec *one,
3971                                 struct diff_filespec *two)
3972{
3973        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3974        dp->one = one;
3975        dp->two = two;
3976        if (queue)
3977                diff_q(queue, dp);
3978        return dp;
3979}
3980
3981void diff_free_filepair(struct diff_filepair *p)
3982{
3983        free_filespec(p->one);
3984        free_filespec(p->two);
3985        free(p);
3986}
3987
3988/* This is different from find_unique_abbrev() in that
3989 * it stuffs the result with dots for alignment.
3990 */
3991const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3992{
3993        int abblen;
3994        const char *abbrev;
3995        if (len == 40)
3996                return sha1_to_hex(sha1);
3997
3998        abbrev = find_unique_abbrev(sha1, len);
3999        abblen = strlen(abbrev);
4000        if (abblen < 37) {
4001                static char hex[41];
4002                if (len < abblen && abblen <= len + 2)
4003                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
4004                else
4005                        sprintf(hex, "%s...", abbrev);
4006                return hex;
4007        }
4008        return sha1_to_hex(sha1);
4009}
4010
4011static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4012{
4013        int line_termination = opt->line_termination;
4014        int inter_name_termination = line_termination ? '\t' : '\0';
4015
4016        fprintf(opt->file, "%s", diff_line_prefix(opt));
4017        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4018                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4019                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4020                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4021        }
4022        if (p->score) {
4023                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4024                        inter_name_termination);
4025        } else {
4026                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4027        }
4028
4029        if (p->status == DIFF_STATUS_COPIED ||
4030            p->status == DIFF_STATUS_RENAMED) {
4031                const char *name_a, *name_b;
4032                name_a = p->one->path;
4033                name_b = p->two->path;
4034                strip_prefix(opt->prefix_length, &name_a, &name_b);
4035                write_name_quoted(name_a, opt->file, inter_name_termination);
4036                write_name_quoted(name_b, opt->file, line_termination);
4037        } else {
4038                const char *name_a, *name_b;
4039                name_a = p->one->mode ? p->one->path : p->two->path;
4040                name_b = NULL;
4041                strip_prefix(opt->prefix_length, &name_a, &name_b);
4042                write_name_quoted(name_a, opt->file, line_termination);
4043        }
4044}
4045
4046int diff_unmodified_pair(struct diff_filepair *p)
4047{
4048        /* This function is written stricter than necessary to support
4049         * the currently implemented transformers, but the idea is to
4050         * let transformers to produce diff_filepairs any way they want,
4051         * and filter and clean them up here before producing the output.
4052         */
4053        struct diff_filespec *one = p->one, *two = p->two;
4054
4055        if (DIFF_PAIR_UNMERGED(p))
4056                return 0; /* unmerged is interesting */
4057
4058        /* deletion, addition, mode or type change
4059         * and rename are all interesting.
4060         */
4061        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4062            DIFF_PAIR_MODE_CHANGED(p) ||
4063            strcmp(one->path, two->path))
4064                return 0;
4065
4066        /* both are valid and point at the same path.  that is, we are
4067         * dealing with a change.
4068         */
4069        if (one->sha1_valid && two->sha1_valid &&
4070            !hashcmp(one->sha1, two->sha1) &&
4071            !one->dirty_submodule && !two->dirty_submodule)
4072                return 1; /* no change */
4073        if (!one->sha1_valid && !two->sha1_valid)
4074                return 1; /* both look at the same file on the filesystem. */
4075        return 0;
4076}
4077
4078static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4079{
4080        if (diff_unmodified_pair(p))
4081                return;
4082
4083        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4084            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4085                return; /* no tree diffs in patch format */
4086
4087        run_diff(p, o);
4088}
4089
4090static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4091                            struct diffstat_t *diffstat)
4092{
4093        if (diff_unmodified_pair(p))
4094                return;
4095
4096        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4097            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4098                return; /* no useful stat for tree diffs */
4099
4100        run_diffstat(p, o, diffstat);
4101}
4102
4103static void diff_flush_checkdiff(struct diff_filepair *p,
4104                struct diff_options *o)
4105{
4106        if (diff_unmodified_pair(p))
4107                return;
4108
4109        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4110            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4111                return; /* nothing to check in tree diffs */
4112
4113        run_checkdiff(p, o);
4114}
4115
4116int diff_queue_is_empty(void)
4117{
4118        struct diff_queue_struct *q = &diff_queued_diff;
4119        int i;
4120        for (i = 0; i < q->nr; i++)
4121                if (!diff_unmodified_pair(q->queue[i]))
4122                        return 0;
4123        return 1;
4124}
4125
4126#if DIFF_DEBUG
4127void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4128{
4129        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4130                x, one ? one : "",
4131                s->path,
4132                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4133                s->mode,
4134                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4135        fprintf(stderr, "queue[%d] %s size %lu\n",
4136                x, one ? one : "",
4137                s->size);
4138}
4139
4140void diff_debug_filepair(const struct diff_filepair *p, int i)
4141{
4142        diff_debug_filespec(p->one, i, "one");
4143        diff_debug_filespec(p->two, i, "two");
4144        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4145                p->score, p->status ? p->status : '?',
4146                p->one->rename_used, p->broken_pair);
4147}
4148
4149void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4150{
4151        int i;
4152        if (msg)
4153                fprintf(stderr, "%s\n", msg);
4154        fprintf(stderr, "q->nr = %d\n", q->nr);
4155        for (i = 0; i < q->nr; i++) {
4156                struct diff_filepair *p = q->queue[i];
4157                diff_debug_filepair(p, i);
4158        }
4159}
4160#endif
4161
4162static void diff_resolve_rename_copy(void)
4163{
4164        int i;
4165        struct diff_filepair *p;
4166        struct diff_queue_struct *q = &diff_queued_diff;
4167
4168        diff_debug_queue("resolve-rename-copy", q);
4169
4170        for (i = 0; i < q->nr; i++) {
4171                p = q->queue[i];
4172                p->status = 0; /* undecided */
4173                if (DIFF_PAIR_UNMERGED(p))
4174                        p->status = DIFF_STATUS_UNMERGED;
4175                else if (!DIFF_FILE_VALID(p->one))
4176                        p->status = DIFF_STATUS_ADDED;
4177                else if (!DIFF_FILE_VALID(p->two))
4178                        p->status = DIFF_STATUS_DELETED;
4179                else if (DIFF_PAIR_TYPE_CHANGED(p))
4180                        p->status = DIFF_STATUS_TYPE_CHANGED;
4181
4182                /* from this point on, we are dealing with a pair
4183                 * whose both sides are valid and of the same type, i.e.
4184                 * either in-place edit or rename/copy edit.
4185                 */
4186                else if (DIFF_PAIR_RENAME(p)) {
4187                        /*
4188                         * A rename might have re-connected a broken
4189                         * pair up, causing the pathnames to be the
4190                         * same again. If so, that's not a rename at
4191                         * all, just a modification..
4192                         *
4193                         * Otherwise, see if this source was used for
4194                         * multiple renames, in which case we decrement
4195                         * the count, and call it a copy.
4196                         */
4197                        if (!strcmp(p->one->path, p->two->path))
4198                                p->status = DIFF_STATUS_MODIFIED;
4199                        else if (--p->one->rename_used > 0)
4200                                p->status = DIFF_STATUS_COPIED;
4201                        else
4202                                p->status = DIFF_STATUS_RENAMED;
4203                }
4204                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4205                         p->one->mode != p->two->mode ||
4206                         p->one->dirty_submodule ||
4207                         p->two->dirty_submodule ||
4208                         is_null_sha1(p->one->sha1))
4209                        p->status = DIFF_STATUS_MODIFIED;
4210                else {
4211                        /* This is a "no-change" entry and should not
4212                         * happen anymore, but prepare for broken callers.
4213                         */
4214                        error("feeding unmodified %s to diffcore",
4215                              p->one->path);
4216                        p->status = DIFF_STATUS_UNKNOWN;
4217                }
4218        }
4219        diff_debug_queue("resolve-rename-copy done", q);
4220}
4221
4222static int check_pair_status(struct diff_filepair *p)
4223{
4224        switch (p->status) {
4225        case DIFF_STATUS_UNKNOWN:
4226                return 0;
4227        case 0:
4228                die("internal error in diff-resolve-rename-copy");
4229        default:
4230                return 1;
4231        }
4232}
4233
4234static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4235{
4236        int fmt = opt->output_format;
4237
4238        if (fmt & DIFF_FORMAT_CHECKDIFF)
4239                diff_flush_checkdiff(p, opt);
4240        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4241                diff_flush_raw(p, opt);
4242        else if (fmt & DIFF_FORMAT_NAME) {
4243                const char *name_a, *name_b;
4244                name_a = p->two->path;
4245                name_b = NULL;
4246                strip_prefix(opt->prefix_length, &name_a, &name_b);
4247                write_name_quoted(name_a, opt->file, opt->line_termination);
4248        }
4249}
4250
4251static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4252{
4253        if (fs->mode)
4254                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4255        else
4256                fprintf(file, " %s ", newdelete);
4257        write_name_quoted(fs->path, file, '\n');
4258}
4259
4260
4261static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4262                const char *line_prefix)
4263{
4264        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4265                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4266                        p->two->mode, show_name ? ' ' : '\n');
4267                if (show_name) {
4268                        write_name_quoted(p->two->path, file, '\n');
4269                }
4270        }
4271}
4272
4273static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4274                        const char *line_prefix)
4275{
4276        char *names = pprint_rename(p->one->path, p->two->path);
4277
4278        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4279        free(names);
4280        show_mode_change(file, p, 0, line_prefix);
4281}
4282
4283static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4284{
4285        FILE *file = opt->file;
4286        const char *line_prefix = diff_line_prefix(opt);
4287
4288        switch(p->status) {
4289        case DIFF_STATUS_DELETED:
4290                fputs(line_prefix, file);
4291                show_file_mode_name(file, "delete", p->one);
4292                break;
4293        case DIFF_STATUS_ADDED:
4294                fputs(line_prefix, file);
4295                show_file_mode_name(file, "create", p->two);
4296                break;
4297        case DIFF_STATUS_COPIED:
4298                fputs(line_prefix, file);
4299                show_rename_copy(file, "copy", p, line_prefix);
4300                break;
4301        case DIFF_STATUS_RENAMED:
4302                fputs(line_prefix, file);
4303                show_rename_copy(file, "rename", p, line_prefix);
4304                break;
4305        default:
4306                if (p->score) {
4307                        fprintf(file, "%s rewrite ", line_prefix);
4308                        write_name_quoted(p->two->path, file, ' ');
4309                        fprintf(file, "(%d%%)\n", similarity_index(p));
4310                }
4311                show_mode_change(file, p, !p->score, line_prefix);
4312                break;
4313        }
4314}
4315
4316struct patch_id_t {
4317        git_SHA_CTX *ctx;
4318        int patchlen;
4319};
4320
4321static int remove_space(char *line, int len)
4322{
4323        int i;
4324        char *dst = line;
4325        unsigned char c;
4326
4327        for (i = 0; i < len; i++)
4328                if (!isspace((c = line[i])))
4329                        *dst++ = c;
4330
4331        return dst - line;
4332}
4333
4334static void patch_id_consume(void *priv, char *line, unsigned long len)
4335{
4336        struct patch_id_t *data = priv;
4337        int new_len;
4338
4339        /* Ignore line numbers when computing the SHA1 of the patch */
4340        if (starts_with(line, "@@ -"))
4341                return;
4342
4343        new_len = remove_space(line, len);
4344
4345        git_SHA1_Update(data->ctx, line, new_len);
4346        data->patchlen += new_len;
4347}
4348
4349/* returns 0 upon success, and writes result into sha1 */
4350static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4351{
4352        struct diff_queue_struct *q = &diff_queued_diff;
4353        int i;
4354        git_SHA_CTX ctx;
4355        struct patch_id_t data;
4356        char buffer[PATH_MAX * 4 + 20];
4357
4358        git_SHA1_Init(&ctx);
4359        memset(&data, 0, sizeof(struct patch_id_t));
4360        data.ctx = &ctx;
4361
4362        for (i = 0; i < q->nr; i++) {
4363                xpparam_t xpp;
4364                xdemitconf_t xecfg;
4365                mmfile_t mf1, mf2;
4366                struct diff_filepair *p = q->queue[i];
4367                int len1, len2;
4368
4369                memset(&xpp, 0, sizeof(xpp));
4370                memset(&xecfg, 0, sizeof(xecfg));
4371                if (p->status == 0)
4372                        return error("internal diff status error");
4373                if (p->status == DIFF_STATUS_UNKNOWN)
4374                        continue;
4375                if (diff_unmodified_pair(p))
4376                        continue;
4377                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4378                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4379                        continue;
4380                if (DIFF_PAIR_UNMERGED(p))
4381                        continue;
4382
4383                diff_fill_sha1_info(p->one);
4384                diff_fill_sha1_info(p->two);
4385                if (fill_mmfile(&mf1, p->one) < 0 ||
4386                                fill_mmfile(&mf2, p->two) < 0)
4387                        return error("unable to read files to diff");
4388
4389                len1 = remove_space(p->one->path, strlen(p->one->path));
4390                len2 = remove_space(p->two->path, strlen(p->two->path));
4391                if (p->one->mode == 0)
4392                        len1 = snprintf(buffer, sizeof(buffer),
4393                                        "diff--gita/%.*sb/%.*s"
4394                                        "newfilemode%06o"
4395                                        "---/dev/null"
4396                                        "+++b/%.*s",
4397                                        len1, p->one->path,
4398                                        len2, p->two->path,
4399                                        p->two->mode,
4400                                        len2, p->two->path);
4401                else if (p->two->mode == 0)
4402                        len1 = snprintf(buffer, sizeof(buffer),
4403                                        "diff--gita/%.*sb/%.*s"
4404                                        "deletedfilemode%06o"
4405                                        "---a/%.*s"
4406                                        "+++/dev/null",
4407                                        len1, p->one->path,
4408                                        len2, p->two->path,
4409                                        p->one->mode,
4410                                        len1, p->one->path);
4411                else
4412                        len1 = snprintf(buffer, sizeof(buffer),
4413                                        "diff--gita/%.*sb/%.*s"
4414                                        "---a/%.*s"
4415                                        "+++b/%.*s",
4416                                        len1, p->one->path,
4417                                        len2, p->two->path,
4418                                        len1, p->one->path,
4419                                        len2, p->two->path);
4420                git_SHA1_Update(&ctx, buffer, len1);
4421
4422                if (diff_filespec_is_binary(p->one) ||
4423                    diff_filespec_is_binary(p->two)) {
4424                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4425                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4426                        continue;
4427                }
4428
4429                xpp.flags = 0;
4430                xecfg.ctxlen = 3;
4431                xecfg.flags = 0;
4432                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4433                                  &xpp, &xecfg))
4434                        return error("unable to generate patch-id diff for %s",
4435                                     p->one->path);
4436        }
4437
4438        git_SHA1_Final(sha1, &ctx);
4439        return 0;
4440}
4441
4442int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4443{
4444        struct diff_queue_struct *q = &diff_queued_diff;
4445        int i;
4446        int result = diff_get_patch_id(options, sha1);
4447
4448        for (i = 0; i < q->nr; i++)
4449                diff_free_filepair(q->queue[i]);
4450
4451        free(q->queue);
4452        DIFF_QUEUE_CLEAR(q);
4453
4454        return result;
4455}
4456
4457static int is_summary_empty(const struct diff_queue_struct *q)
4458{
4459        int i;
4460
4461        for (i = 0; i < q->nr; i++) {
4462                const struct diff_filepair *p = q->queue[i];
4463
4464                switch (p->status) {
4465                case DIFF_STATUS_DELETED:
4466                case DIFF_STATUS_ADDED:
4467                case DIFF_STATUS_COPIED:
4468                case DIFF_STATUS_RENAMED:
4469                        return 0;
4470                default:
4471                        if (p->score)
4472                                return 0;
4473                        if (p->one->mode && p->two->mode &&
4474                            p->one->mode != p->two->mode)
4475                                return 0;
4476                        break;
4477                }
4478        }
4479        return 1;
4480}
4481
4482static const char rename_limit_warning[] =
4483"inexact rename detection was skipped due to too many files.";
4484
4485static const char degrade_cc_to_c_warning[] =
4486"only found copies from modified paths due to too many files.";
4487
4488static const char rename_limit_advice[] =
4489"you may want to set your %s variable to at least "
4490"%d and retry the command.";
4491
4492void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4493{
4494        if (degraded_cc)
4495                warning(degrade_cc_to_c_warning);
4496        else if (needed)
4497                warning(rename_limit_warning);
4498        else
4499                return;
4500        if (0 < needed && needed < 32767)
4501                warning(rename_limit_advice, varname, needed);
4502}
4503
4504void diff_flush(struct diff_options *options)
4505{
4506        struct diff_queue_struct *q = &diff_queued_diff;
4507        int i, output_format = options->output_format;
4508        int separator = 0;
4509        int dirstat_by_line = 0;
4510
4511        /*
4512         * Order: raw, stat, summary, patch
4513         * or:    name/name-status/checkdiff (other bits clear)
4514         */
4515        if (!q->nr)
4516                goto free_queue;
4517
4518        if (output_format & (DIFF_FORMAT_RAW |
4519                             DIFF_FORMAT_NAME |
4520                             DIFF_FORMAT_NAME_STATUS |
4521                             DIFF_FORMAT_CHECKDIFF)) {
4522                for (i = 0; i < q->nr; i++) {
4523                        struct diff_filepair *p = q->queue[i];
4524                        if (check_pair_status(p))
4525                                flush_one_pair(p, options);
4526                }
4527                separator++;
4528        }
4529
4530        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4531                dirstat_by_line = 1;
4532
4533        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4534            dirstat_by_line) {
4535                struct diffstat_t diffstat;
4536
4537                memset(&diffstat, 0, sizeof(struct diffstat_t));
4538                for (i = 0; i < q->nr; i++) {
4539                        struct diff_filepair *p = q->queue[i];
4540                        if (check_pair_status(p))
4541                                diff_flush_stat(p, options, &diffstat);
4542                }
4543                if (output_format & DIFF_FORMAT_NUMSTAT)
4544                        show_numstat(&diffstat, options);
4545                if (output_format & DIFF_FORMAT_DIFFSTAT)
4546                        show_stats(&diffstat, options);
4547                if (output_format & DIFF_FORMAT_SHORTSTAT)
4548                        show_shortstats(&diffstat, options);
4549                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4550                        show_dirstat_by_line(&diffstat, options);
4551                free_diffstat_info(&diffstat);
4552                separator++;
4553        }
4554        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4555                show_dirstat(options);
4556
4557        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4558                for (i = 0; i < q->nr; i++) {
4559                        diff_summary(options, q->queue[i]);
4560                }
4561                separator++;
4562        }
4563
4564        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4565            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4566            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4567                /*
4568                 * run diff_flush_patch for the exit status. setting
4569                 * options->file to /dev/null should be safe, because we
4570                 * aren't supposed to produce any output anyway.
4571                 */
4572                if (options->close_file)
4573                        fclose(options->file);
4574                options->file = fopen("/dev/null", "w");
4575                if (!options->file)
4576                        die_errno("Could not open /dev/null");
4577                options->close_file = 1;
4578                for (i = 0; i < q->nr; i++) {
4579                        struct diff_filepair *p = q->queue[i];
4580                        if (check_pair_status(p))
4581                                diff_flush_patch(p, options);
4582                        if (options->found_changes)
4583                                break;
4584                }
4585        }
4586
4587        if (output_format & DIFF_FORMAT_PATCH) {
4588                if (separator) {
4589                        fprintf(options->file, "%s%c",
4590                                diff_line_prefix(options),
4591                                options->line_termination);
4592                        if (options->stat_sep) {
4593                                /* attach patch instead of inline */
4594                                fputs(options->stat_sep, options->file);
4595                        }
4596                }
4597
4598                for (i = 0; i < q->nr; i++) {
4599                        struct diff_filepair *p = q->queue[i];
4600                        if (check_pair_status(p))
4601                                diff_flush_patch(p, options);
4602                }
4603        }
4604
4605        if (output_format & DIFF_FORMAT_CALLBACK)
4606                options->format_callback(q, options, options->format_callback_data);
4607
4608        for (i = 0; i < q->nr; i++)
4609                diff_free_filepair(q->queue[i]);
4610free_queue:
4611        free(q->queue);
4612        DIFF_QUEUE_CLEAR(q);
4613        if (options->close_file)
4614                fclose(options->file);
4615
4616        /*
4617         * Report the content-level differences with HAS_CHANGES;
4618         * diff_addremove/diff_change does not set the bit when
4619         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4620         */
4621        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4622                if (options->found_changes)
4623                        DIFF_OPT_SET(options, HAS_CHANGES);
4624                else
4625                        DIFF_OPT_CLR(options, HAS_CHANGES);
4626        }
4627}
4628
4629static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4630{
4631        return (((p->status == DIFF_STATUS_MODIFIED) &&
4632                 ((p->score &&
4633                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4634                  (!p->score &&
4635                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4636                ((p->status != DIFF_STATUS_MODIFIED) &&
4637                 filter_bit_tst(p->status, options)));
4638}
4639
4640static void diffcore_apply_filter(struct diff_options *options)
4641{
4642        int i;
4643        struct diff_queue_struct *q = &diff_queued_diff;
4644        struct diff_queue_struct outq;
4645
4646        DIFF_QUEUE_CLEAR(&outq);
4647
4648        if (!options->filter)
4649                return;
4650
4651        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4652                int found;
4653                for (i = found = 0; !found && i < q->nr; i++) {
4654                        if (match_filter(options, q->queue[i]))
4655                                found++;
4656                }
4657                if (found)
4658                        return;
4659
4660                /* otherwise we will clear the whole queue
4661                 * by copying the empty outq at the end of this
4662                 * function, but first clear the current entries
4663                 * in the queue.
4664                 */
4665                for (i = 0; i < q->nr; i++)
4666                        diff_free_filepair(q->queue[i]);
4667        }
4668        else {
4669                /* Only the matching ones */
4670                for (i = 0; i < q->nr; i++) {
4671                        struct diff_filepair *p = q->queue[i];
4672                        if (match_filter(options, p))
4673                                diff_q(&outq, p);
4674                        else
4675                                diff_free_filepair(p);
4676                }
4677        }
4678        free(q->queue);
4679        *q = outq;
4680}
4681
4682/* Check whether two filespecs with the same mode and size are identical */
4683static int diff_filespec_is_identical(struct diff_filespec *one,
4684                                      struct diff_filespec *two)
4685{
4686        if (S_ISGITLINK(one->mode))
4687                return 0;
4688        if (diff_populate_filespec(one, 0))
4689                return 0;
4690        if (diff_populate_filespec(two, 0))
4691                return 0;
4692        return !memcmp(one->data, two->data, one->size);
4693}
4694
4695static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4696{
4697        if (p->done_skip_stat_unmatch)
4698                return p->skip_stat_unmatch_result;
4699
4700        p->done_skip_stat_unmatch = 1;
4701        p->skip_stat_unmatch_result = 0;
4702        /*
4703         * 1. Entries that come from stat info dirtiness
4704         *    always have both sides (iow, not create/delete),
4705         *    one side of the object name is unknown, with
4706         *    the same mode and size.  Keep the ones that
4707         *    do not match these criteria.  They have real
4708         *    differences.
4709         *
4710         * 2. At this point, the file is known to be modified,
4711         *    with the same mode and size, and the object
4712         *    name of one side is unknown.  Need to inspect
4713         *    the identical contents.
4714         */
4715        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4716            !DIFF_FILE_VALID(p->two) ||
4717            (p->one->sha1_valid && p->two->sha1_valid) ||
4718            (p->one->mode != p->two->mode) ||
4719            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4720            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4721            (p->one->size != p->two->size) ||
4722            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4723                p->skip_stat_unmatch_result = 1;
4724        return p->skip_stat_unmatch_result;
4725}
4726
4727static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4728{
4729        int i;
4730        struct diff_queue_struct *q = &diff_queued_diff;
4731        struct diff_queue_struct outq;
4732        DIFF_QUEUE_CLEAR(&outq);
4733
4734        for (i = 0; i < q->nr; i++) {
4735                struct diff_filepair *p = q->queue[i];
4736
4737                if (diff_filespec_check_stat_unmatch(p))
4738                        diff_q(&outq, p);
4739                else {
4740                        /*
4741                         * The caller can subtract 1 from skip_stat_unmatch
4742                         * to determine how many paths were dirty only
4743                         * due to stat info mismatch.
4744                         */
4745                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4746                                diffopt->skip_stat_unmatch++;
4747                        diff_free_filepair(p);
4748                }
4749        }
4750        free(q->queue);
4751        *q = outq;
4752}
4753
4754static int diffnamecmp(const void *a_, const void *b_)
4755{
4756        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4757        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4758        const char *name_a, *name_b;
4759
4760        name_a = a->one ? a->one->path : a->two->path;
4761        name_b = b->one ? b->one->path : b->two->path;
4762        return strcmp(name_a, name_b);
4763}
4764
4765void diffcore_fix_diff_index(struct diff_options *options)
4766{
4767        struct diff_queue_struct *q = &diff_queued_diff;
4768        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4769}
4770
4771void diffcore_std(struct diff_options *options)
4772{
4773        /* NOTE please keep the following in sync with diff_tree_combined() */
4774        if (options->skip_stat_unmatch)
4775                diffcore_skip_stat_unmatch(options);
4776        if (!options->found_follow) {
4777                /* See try_to_follow_renames() in tree-diff.c */
4778                if (options->break_opt != -1)
4779                        diffcore_break(options->break_opt);
4780                if (options->detect_rename)
4781                        diffcore_rename(options);
4782                if (options->break_opt != -1)
4783                        diffcore_merge_broken();
4784        }
4785        if (options->pickaxe)
4786                diffcore_pickaxe(options);
4787        if (options->orderfile)
4788                diffcore_order(options->orderfile);
4789        if (!options->found_follow)
4790                /* See try_to_follow_renames() in tree-diff.c */
4791                diff_resolve_rename_copy();
4792        diffcore_apply_filter(options);
4793
4794        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4795                DIFF_OPT_SET(options, HAS_CHANGES);
4796        else
4797                DIFF_OPT_CLR(options, HAS_CHANGES);
4798
4799        options->found_follow = 0;
4800}
4801
4802int diff_result_code(struct diff_options *opt, int status)
4803{
4804        int result = 0;
4805
4806        diff_warn_rename_limit("diff.renameLimit",
4807                               opt->needed_rename_limit,
4808                               opt->degraded_cc_to_c);
4809        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4810            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4811                return status;
4812        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4813            DIFF_OPT_TST(opt, HAS_CHANGES))
4814                result |= 01;
4815        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4816            DIFF_OPT_TST(opt, CHECK_FAILED))
4817                result |= 02;
4818        return result;
4819}
4820
4821int diff_can_quit_early(struct diff_options *opt)
4822{
4823        return (DIFF_OPT_TST(opt, QUICK) &&
4824                !opt->filter &&
4825                DIFF_OPT_TST(opt, HAS_CHANGES));
4826}
4827
4828/*
4829 * Shall changes to this submodule be ignored?
4830 *
4831 * Submodule changes can be configured to be ignored separately for each path,
4832 * but that configuration can be overridden from the command line.
4833 */
4834static int is_submodule_ignored(const char *path, struct diff_options *options)
4835{
4836        int ignored = 0;
4837        unsigned orig_flags = options->flags;
4838        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4839                set_diffopt_flags_from_submodule_config(options, path);
4840        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4841                ignored = 1;
4842        options->flags = orig_flags;
4843        return ignored;
4844}
4845
4846void diff_addremove(struct diff_options *options,
4847                    int addremove, unsigned mode,
4848                    const unsigned char *sha1,
4849                    int sha1_valid,
4850                    const char *concatpath, unsigned dirty_submodule)
4851{
4852        struct diff_filespec *one, *two;
4853
4854        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4855                return;
4856
4857        /* This may look odd, but it is a preparation for
4858         * feeding "there are unchanged files which should
4859         * not produce diffs, but when you are doing copy
4860         * detection you would need them, so here they are"
4861         * entries to the diff-core.  They will be prefixed
4862         * with something like '=' or '*' (I haven't decided
4863         * which but should not make any difference).
4864         * Feeding the same new and old to diff_change()
4865         * also has the same effect.
4866         * Before the final output happens, they are pruned after
4867         * merged into rename/copy pairs as appropriate.
4868         */
4869        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4870                addremove = (addremove == '+' ? '-' :
4871                             addremove == '-' ? '+' : addremove);
4872
4873        if (options->prefix &&
4874            strncmp(concatpath, options->prefix, options->prefix_length))
4875                return;
4876
4877        one = alloc_filespec(concatpath);
4878        two = alloc_filespec(concatpath);
4879
4880        if (addremove != '+')
4881                fill_filespec(one, sha1, sha1_valid, mode);
4882        if (addremove != '-') {
4883                fill_filespec(two, sha1, sha1_valid, mode);
4884                two->dirty_submodule = dirty_submodule;
4885        }
4886
4887        diff_queue(&diff_queued_diff, one, two);
4888        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4889                DIFF_OPT_SET(options, HAS_CHANGES);
4890}
4891
4892void diff_change(struct diff_options *options,
4893                 unsigned old_mode, unsigned new_mode,
4894                 const unsigned char *old_sha1,
4895                 const unsigned char *new_sha1,
4896                 int old_sha1_valid, int new_sha1_valid,
4897                 const char *concatpath,
4898                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4899{
4900        struct diff_filespec *one, *two;
4901        struct diff_filepair *p;
4902
4903        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4904            is_submodule_ignored(concatpath, options))
4905                return;
4906
4907        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4908                unsigned tmp;
4909                const unsigned char *tmp_c;
4910                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4911                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4912                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4913                        new_sha1_valid = tmp;
4914                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4915                        new_dirty_submodule = tmp;
4916        }
4917
4918        if (options->prefix &&
4919            strncmp(concatpath, options->prefix, options->prefix_length))
4920                return;
4921
4922        one = alloc_filespec(concatpath);
4923        two = alloc_filespec(concatpath);
4924        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4925        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4926        one->dirty_submodule = old_dirty_submodule;
4927        two->dirty_submodule = new_dirty_submodule;
4928        p = diff_queue(&diff_queued_diff, one, two);
4929
4930        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4931                return;
4932
4933        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
4934            !diff_filespec_check_stat_unmatch(p))
4935                return;
4936
4937        DIFF_OPT_SET(options, HAS_CHANGES);
4938}
4939
4940struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4941{
4942        struct diff_filepair *pair;
4943        struct diff_filespec *one, *two;
4944
4945        if (options->prefix &&
4946            strncmp(path, options->prefix, options->prefix_length))
4947                return NULL;
4948
4949        one = alloc_filespec(path);
4950        two = alloc_filespec(path);
4951        pair = diff_queue(&diff_queued_diff, one, two);
4952        pair->is_unmerged = 1;
4953        return pair;
4954}
4955
4956static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4957                size_t *outsize)
4958{
4959        struct diff_tempfile *temp;
4960        const char *argv[3];
4961        const char **arg = argv;
4962        struct child_process child = CHILD_PROCESS_INIT;
4963        struct strbuf buf = STRBUF_INIT;
4964        int err = 0;
4965
4966        temp = prepare_temp_file(spec->path, spec);
4967        *arg++ = pgm;
4968        *arg++ = temp->name;
4969        *arg = NULL;
4970
4971        child.use_shell = 1;
4972        child.argv = argv;
4973        child.out = -1;
4974        if (start_command(&child)) {
4975                remove_tempfile();
4976                return NULL;
4977        }
4978
4979        if (strbuf_read(&buf, child.out, 0) < 0)
4980                err = error("error reading from textconv command '%s'", pgm);
4981        close(child.out);
4982
4983        if (finish_command(&child) || err) {
4984                strbuf_release(&buf);
4985                remove_tempfile();
4986                return NULL;
4987        }
4988        remove_tempfile();
4989
4990        return strbuf_detach(&buf, outsize);
4991}
4992
4993size_t fill_textconv(struct userdiff_driver *driver,
4994                     struct diff_filespec *df,
4995                     char **outbuf)
4996{
4997        size_t size;
4998
4999        if (!driver || !driver->textconv) {
5000                if (!DIFF_FILE_VALID(df)) {
5001                        *outbuf = "";
5002                        return 0;
5003                }
5004                if (diff_populate_filespec(df, 0))
5005                        die("unable to read files to diff");
5006                *outbuf = df->data;
5007                return df->size;
5008        }
5009
5010        if (driver->textconv_cache && df->sha1_valid) {
5011                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5012                                          &size);
5013                if (*outbuf)
5014                        return size;
5015        }
5016
5017        *outbuf = run_textconv(driver->textconv, df, &size);
5018        if (!*outbuf)
5019                die("unable to read files to diff");
5020
5021        if (driver->textconv_cache && df->sha1_valid) {
5022                /* ignore errors, as we might be in a readonly repository */
5023                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5024                                size);
5025                /*
5026                 * we could save up changes and flush them all at the end,
5027                 * but we would need an extra call after all diffing is done.
5028                 * Since generating a cache entry is the slow path anyway,
5029                 * this extra overhead probably isn't a big deal.
5030                 */
5031                notes_cache_write(driver->textconv_cache);
5032        }
5033
5034        return size;
5035}
5036
5037void setup_diff_pager(struct diff_options *opt)
5038{
5039        /*
5040         * If the user asked for our exit code, then either they want --quiet
5041         * or --exit-code. We should definitely not bother with a pager in the
5042         * former case, as we will generate no output. Since we still properly
5043         * report our exit code even when a pager is run, we _could_ run a
5044         * pager with --exit-code. But since we have not done so historically,
5045         * and because it is easy to find people oneline advising "git diff
5046         * --exit-code" in hooks and other scripts, we do not do so.
5047         */
5048        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5049            check_pager_config("diff") != 0)
5050                setup_pager();
5051}