0496cdc0197ced2196e45d8e54c1f930f4ee4611
   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
  19#ifdef NO_FAST_WORKING_DIRECTORY
  20#define FAST_WORKING_DIRECTORY 0
  21#else
  22#define FAST_WORKING_DIRECTORY 1
  23#endif
  24
  25static int diff_detect_rename_default;
  26static int diff_rename_limit_default = 400;
  27static int diff_suppress_blank_empty;
  28int diff_use_color_default = -1;
  29static const char *diff_word_regex_cfg;
  30static const char *external_diff_cmd_cfg;
  31int diff_auto_refresh_index = 1;
  32static int diff_mnemonic_prefix;
  33static int diff_no_prefix;
  34static int diff_dirstat_permille_default = 30;
  35static struct diff_options default_diff_options;
  36
  37static char diff_colors[][COLOR_MAXLEN] = {
  38        GIT_COLOR_RESET,
  39        GIT_COLOR_NORMAL,       /* PLAIN */
  40        GIT_COLOR_BOLD,         /* METAINFO */
  41        GIT_COLOR_CYAN,         /* FRAGINFO */
  42        GIT_COLOR_RED,          /* OLD */
  43        GIT_COLOR_GREEN,        /* NEW */
  44        GIT_COLOR_YELLOW,       /* COMMIT */
  45        GIT_COLOR_BG_RED,       /* WHITESPACE */
  46        GIT_COLOR_NORMAL,       /* FUNCINFO */
  47};
  48
  49static int parse_diff_color_slot(const char *var, int ofs)
  50{
  51        if (!strcasecmp(var+ofs, "plain"))
  52                return DIFF_PLAIN;
  53        if (!strcasecmp(var+ofs, "meta"))
  54                return DIFF_METAINFO;
  55        if (!strcasecmp(var+ofs, "frag"))
  56                return DIFF_FRAGINFO;
  57        if (!strcasecmp(var+ofs, "old"))
  58                return DIFF_FILE_OLD;
  59        if (!strcasecmp(var+ofs, "new"))
  60                return DIFF_FILE_NEW;
  61        if (!strcasecmp(var+ofs, "commit"))
  62                return DIFF_COMMIT;
  63        if (!strcasecmp(var+ofs, "whitespace"))
  64                return DIFF_WHITESPACE;
  65        if (!strcasecmp(var+ofs, "func"))
  66                return DIFF_FUNCINFO;
  67        return -1;
  68}
  69
  70static int parse_dirstat_params(struct diff_options *options, const char *params,
  71                                struct strbuf *errmsg)
  72{
  73        const char *p = params;
  74        int p_len, ret = 0;
  75
  76        while (*p) {
  77                p_len = strchrnul(p, ',') - p;
  78                if (!memcmp(p, "changes", p_len)) {
  79                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  80                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  81                } else if (!memcmp(p, "lines", p_len)) {
  82                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  83                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  84                } else if (!memcmp(p, "files", p_len)) {
  85                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  86                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  87                } else if (!memcmp(p, "noncumulative", p_len)) {
  88                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  89                } else if (!memcmp(p, "cumulative", p_len)) {
  90                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  91                } else if (isdigit(*p)) {
  92                        char *end;
  93                        int permille = strtoul(p, &end, 10) * 10;
  94                        if (*end == '.' && isdigit(*++end)) {
  95                                /* only use first digit */
  96                                permille += *end - '0';
  97                                /* .. and ignore any further digits */
  98                                while (isdigit(*++end))
  99                                        ; /* nothing */
 100                        }
 101                        if (end - p == p_len)
 102                                options->dirstat_permille = permille;
 103                        else {
 104                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%.*s'\n"),
 105                                            p_len, p);
 106                                ret++;
 107                        }
 108                } else {
 109                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%.*s'\n"),
 110                                    p_len, p);
 111                        ret++;
 112                }
 113
 114                p += p_len;
 115
 116                if (*p)
 117                        p++; /* more parameters, swallow separator */
 118        }
 119        return ret;
 120}
 121
 122static int git_config_rename(const char *var, const char *value)
 123{
 124        if (!value)
 125                return DIFF_DETECT_RENAME;
 126        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 127                return  DIFF_DETECT_COPY;
 128        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 129}
 130
 131/*
 132 * These are to give UI layer defaults.
 133 * The core-level commands such as git-diff-files should
 134 * never be affected by the setting of diff.renames
 135 * the user happens to have in the configuration file.
 136 */
 137int git_diff_ui_config(const char *var, const char *value, void *cb)
 138{
 139        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 140                diff_use_color_default = git_config_colorbool(var, value);
 141                return 0;
 142        }
 143        if (!strcmp(var, "diff.renames")) {
 144                diff_detect_rename_default = git_config_rename(var, value);
 145                return 0;
 146        }
 147        if (!strcmp(var, "diff.autorefreshindex")) {
 148                diff_auto_refresh_index = git_config_bool(var, value);
 149                return 0;
 150        }
 151        if (!strcmp(var, "diff.mnemonicprefix")) {
 152                diff_mnemonic_prefix = git_config_bool(var, value);
 153                return 0;
 154        }
 155        if (!strcmp(var, "diff.noprefix")) {
 156                diff_no_prefix = git_config_bool(var, value);
 157                return 0;
 158        }
 159        if (!strcmp(var, "diff.external"))
 160                return git_config_string(&external_diff_cmd_cfg, var, value);
 161        if (!strcmp(var, "diff.wordregex"))
 162                return git_config_string(&diff_word_regex_cfg, var, value);
 163
 164        if (!strcmp(var, "diff.ignoresubmodules"))
 165                handle_ignore_submodules_arg(&default_diff_options, value);
 166
 167        return git_diff_basic_config(var, value, cb);
 168}
 169
 170int git_diff_basic_config(const char *var, const char *value, void *cb)
 171{
 172        if (!strcmp(var, "diff.renamelimit")) {
 173                diff_rename_limit_default = git_config_int(var, value);
 174                return 0;
 175        }
 176
 177        switch (userdiff_config(var, value)) {
 178                case 0: break;
 179                case -1: return -1;
 180                default: return 0;
 181        }
 182
 183        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 184                int slot = parse_diff_color_slot(var, 11);
 185                if (slot < 0)
 186                        return 0;
 187                if (!value)
 188                        return config_error_nonbool(var);
 189                color_parse(value, var, diff_colors[slot]);
 190                return 0;
 191        }
 192
 193        /* like GNU diff's --suppress-blank-empty option  */
 194        if (!strcmp(var, "diff.suppressblankempty") ||
 195                        /* for backwards compatibility */
 196                        !strcmp(var, "diff.suppress-blank-empty")) {
 197                diff_suppress_blank_empty = git_config_bool(var, value);
 198                return 0;
 199        }
 200
 201        if (!strcmp(var, "diff.dirstat")) {
 202                struct strbuf errmsg = STRBUF_INIT;
 203                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 204                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 205                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 206                                errmsg.buf);
 207                strbuf_release(&errmsg);
 208                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 209                return 0;
 210        }
 211
 212        if (!prefixcmp(var, "submodule."))
 213                return parse_submodule_config_option(var, value);
 214
 215        return git_color_default_config(var, value, cb);
 216}
 217
 218static char *quote_two(const char *one, const char *two)
 219{
 220        int need_one = quote_c_style(one, NULL, NULL, 1);
 221        int need_two = quote_c_style(two, NULL, NULL, 1);
 222        struct strbuf res = STRBUF_INIT;
 223
 224        if (need_one + need_two) {
 225                strbuf_addch(&res, '"');
 226                quote_c_style(one, &res, NULL, 1);
 227                quote_c_style(two, &res, NULL, 1);
 228                strbuf_addch(&res, '"');
 229        } else {
 230                strbuf_addstr(&res, one);
 231                strbuf_addstr(&res, two);
 232        }
 233        return strbuf_detach(&res, NULL);
 234}
 235
 236static const char *external_diff(void)
 237{
 238        static const char *external_diff_cmd = NULL;
 239        static int done_preparing = 0;
 240
 241        if (done_preparing)
 242                return external_diff_cmd;
 243        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 244        if (!external_diff_cmd)
 245                external_diff_cmd = external_diff_cmd_cfg;
 246        done_preparing = 1;
 247        return external_diff_cmd;
 248}
 249
 250static struct diff_tempfile {
 251        const char *name; /* filename external diff should read from */
 252        char hex[41];
 253        char mode[10];
 254        char tmp_path[PATH_MAX];
 255} diff_temp[2];
 256
 257typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 258
 259struct emit_callback {
 260        int color_diff;
 261        unsigned ws_rule;
 262        int blank_at_eof_in_preimage;
 263        int blank_at_eof_in_postimage;
 264        int lno_in_preimage;
 265        int lno_in_postimage;
 266        sane_truncate_fn truncate;
 267        const char **label_path;
 268        struct diff_words_data *diff_words;
 269        struct diff_options *opt;
 270        int *found_changesp;
 271        struct strbuf *header;
 272};
 273
 274static int count_lines(const char *data, int size)
 275{
 276        int count, ch, completely_empty = 1, nl_just_seen = 0;
 277        count = 0;
 278        while (0 < size--) {
 279                ch = *data++;
 280                if (ch == '\n') {
 281                        count++;
 282                        nl_just_seen = 1;
 283                        completely_empty = 0;
 284                }
 285                else {
 286                        nl_just_seen = 0;
 287                        completely_empty = 0;
 288                }
 289        }
 290        if (completely_empty)
 291                return 0;
 292        if (!nl_just_seen)
 293                count++; /* no trailing newline */
 294        return count;
 295}
 296
 297static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 298{
 299        if (!DIFF_FILE_VALID(one)) {
 300                mf->ptr = (char *)""; /* does not matter */
 301                mf->size = 0;
 302                return 0;
 303        }
 304        else if (diff_populate_filespec(one, 0))
 305                return -1;
 306
 307        mf->ptr = one->data;
 308        mf->size = one->size;
 309        return 0;
 310}
 311
 312/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 313static unsigned long diff_filespec_size(struct diff_filespec *one)
 314{
 315        if (!DIFF_FILE_VALID(one))
 316                return 0;
 317        diff_populate_filespec(one, 1);
 318        return one->size;
 319}
 320
 321static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 322{
 323        char *ptr = mf->ptr;
 324        long size = mf->size;
 325        int cnt = 0;
 326
 327        if (!size)
 328                return cnt;
 329        ptr += size - 1; /* pointing at the very end */
 330        if (*ptr != '\n')
 331                ; /* incomplete line */
 332        else
 333                ptr--; /* skip the last LF */
 334        while (mf->ptr < ptr) {
 335                char *prev_eol;
 336                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 337                        if (*prev_eol == '\n')
 338                                break;
 339                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 340                        break;
 341                cnt++;
 342                ptr = prev_eol - 1;
 343        }
 344        return cnt;
 345}
 346
 347static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 348                               struct emit_callback *ecbdata)
 349{
 350        int l1, l2, at;
 351        unsigned ws_rule = ecbdata->ws_rule;
 352        l1 = count_trailing_blank(mf1, ws_rule);
 353        l2 = count_trailing_blank(mf2, ws_rule);
 354        if (l2 <= l1) {
 355                ecbdata->blank_at_eof_in_preimage = 0;
 356                ecbdata->blank_at_eof_in_postimage = 0;
 357                return;
 358        }
 359        at = count_lines(mf1->ptr, mf1->size);
 360        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 361
 362        at = count_lines(mf2->ptr, mf2->size);
 363        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 364}
 365
 366static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 367                        int first, const char *line, int len)
 368{
 369        int has_trailing_newline, has_trailing_carriage_return;
 370        int nofirst;
 371        FILE *file = o->file;
 372
 373        if (o->output_prefix) {
 374                struct strbuf *msg = NULL;
 375                msg = o->output_prefix(o, o->output_prefix_data);
 376                assert(msg);
 377                fwrite(msg->buf, msg->len, 1, file);
 378        }
 379
 380        if (len == 0) {
 381                has_trailing_newline = (first == '\n');
 382                has_trailing_carriage_return = (!has_trailing_newline &&
 383                                                (first == '\r'));
 384                nofirst = has_trailing_newline || has_trailing_carriage_return;
 385        } else {
 386                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 387                if (has_trailing_newline)
 388                        len--;
 389                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 390                if (has_trailing_carriage_return)
 391                        len--;
 392                nofirst = 0;
 393        }
 394
 395        if (len || !nofirst) {
 396                fputs(set, file);
 397                if (!nofirst)
 398                        fputc(first, file);
 399                fwrite(line, len, 1, file);
 400                fputs(reset, file);
 401        }
 402        if (has_trailing_carriage_return)
 403                fputc('\r', file);
 404        if (has_trailing_newline)
 405                fputc('\n', file);
 406}
 407
 408static void emit_line(struct diff_options *o, const char *set, const char *reset,
 409                      const char *line, int len)
 410{
 411        emit_line_0(o, set, reset, line[0], line+1, len-1);
 412}
 413
 414static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 415{
 416        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 417              ecbdata->blank_at_eof_in_preimage &&
 418              ecbdata->blank_at_eof_in_postimage &&
 419              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 420              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 421                return 0;
 422        return ws_blank_line(line, len, ecbdata->ws_rule);
 423}
 424
 425static void emit_add_line(const char *reset,
 426                          struct emit_callback *ecbdata,
 427                          const char *line, int len)
 428{
 429        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 430        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 431
 432        if (!*ws)
 433                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 434        else if (new_blank_line_at_eof(ecbdata, line, len))
 435                /* Blank line at EOF - paint '+' as well */
 436                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 437        else {
 438                /* Emit just the prefix, then the rest. */
 439                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 440                ws_check_emit(line, len, ecbdata->ws_rule,
 441                              ecbdata->opt->file, set, reset, ws);
 442        }
 443}
 444
 445static void emit_hunk_header(struct emit_callback *ecbdata,
 446                             const char *line, int len)
 447{
 448        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 449        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 450        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 451        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 452        static const char atat[2] = { '@', '@' };
 453        const char *cp, *ep;
 454        struct strbuf msgbuf = STRBUF_INIT;
 455        int org_len = len;
 456        int i = 1;
 457
 458        /*
 459         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 460         * it always is at least 10 bytes long.
 461         */
 462        if (len < 10 ||
 463            memcmp(line, atat, 2) ||
 464            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 465                emit_line(ecbdata->opt, plain, reset, line, len);
 466                return;
 467        }
 468        ep += 2; /* skip over @@ */
 469
 470        /* The hunk header in fraginfo color */
 471        strbuf_add(&msgbuf, frag, strlen(frag));
 472        strbuf_add(&msgbuf, line, ep - line);
 473        strbuf_add(&msgbuf, reset, strlen(reset));
 474
 475        /*
 476         * trailing "\r\n"
 477         */
 478        for ( ; i < 3; i++)
 479                if (line[len - i] == '\r' || line[len - i] == '\n')
 480                        len--;
 481
 482        /* blank before the func header */
 483        for (cp = ep; ep - line < len; ep++)
 484                if (*ep != ' ' && *ep != '\t')
 485                        break;
 486        if (ep != cp) {
 487                strbuf_add(&msgbuf, plain, strlen(plain));
 488                strbuf_add(&msgbuf, cp, ep - cp);
 489                strbuf_add(&msgbuf, reset, strlen(reset));
 490        }
 491
 492        if (ep < line + len) {
 493                strbuf_add(&msgbuf, func, strlen(func));
 494                strbuf_add(&msgbuf, ep, line + len - ep);
 495                strbuf_add(&msgbuf, reset, strlen(reset));
 496        }
 497
 498        strbuf_add(&msgbuf, line + len, org_len - len);
 499        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 500        strbuf_release(&msgbuf);
 501}
 502
 503static struct diff_tempfile *claim_diff_tempfile(void) {
 504        int i;
 505        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 506                if (!diff_temp[i].name)
 507                        return diff_temp + i;
 508        die("BUG: diff is failing to clean up its tempfiles");
 509}
 510
 511static int remove_tempfile_installed;
 512
 513static void remove_tempfile(void)
 514{
 515        int i;
 516        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 517                if (diff_temp[i].name == diff_temp[i].tmp_path)
 518                        unlink_or_warn(diff_temp[i].name);
 519                diff_temp[i].name = NULL;
 520        }
 521}
 522
 523static void remove_tempfile_on_signal(int signo)
 524{
 525        remove_tempfile();
 526        sigchain_pop(signo);
 527        raise(signo);
 528}
 529
 530static void print_line_count(FILE *file, int count)
 531{
 532        switch (count) {
 533        case 0:
 534                fprintf(file, "0,0");
 535                break;
 536        case 1:
 537                fprintf(file, "1");
 538                break;
 539        default:
 540                fprintf(file, "1,%d", count);
 541                break;
 542        }
 543}
 544
 545static void emit_rewrite_lines(struct emit_callback *ecb,
 546                               int prefix, const char *data, int size)
 547{
 548        const char *endp = NULL;
 549        static const char *nneof = " No newline at end of file\n";
 550        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 551        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 552
 553        while (0 < size) {
 554                int len;
 555
 556                endp = memchr(data, '\n', size);
 557                len = endp ? (endp - data + 1) : size;
 558                if (prefix != '+') {
 559                        ecb->lno_in_preimage++;
 560                        emit_line_0(ecb->opt, old, reset, '-',
 561                                    data, len);
 562                } else {
 563                        ecb->lno_in_postimage++;
 564                        emit_add_line(reset, ecb, data, len);
 565                }
 566                size -= len;
 567                data += len;
 568        }
 569        if (!endp) {
 570                const char *plain = diff_get_color(ecb->color_diff,
 571                                                   DIFF_PLAIN);
 572                emit_line_0(ecb->opt, plain, reset, '\\',
 573                            nneof, strlen(nneof));
 574        }
 575}
 576
 577static void emit_rewrite_diff(const char *name_a,
 578                              const char *name_b,
 579                              struct diff_filespec *one,
 580                              struct diff_filespec *two,
 581                              struct userdiff_driver *textconv_one,
 582                              struct userdiff_driver *textconv_two,
 583                              struct diff_options *o)
 584{
 585        int lc_a, lc_b;
 586        const char *name_a_tab, *name_b_tab;
 587        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 588        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 589        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 590        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 591        const char *a_prefix, *b_prefix;
 592        char *data_one, *data_two;
 593        size_t size_one, size_two;
 594        struct emit_callback ecbdata;
 595        char *line_prefix = "";
 596        struct strbuf *msgbuf;
 597
 598        if (o && o->output_prefix) {
 599                msgbuf = o->output_prefix(o, o->output_prefix_data);
 600                line_prefix = msgbuf->buf;
 601        }
 602
 603        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 604                a_prefix = o->b_prefix;
 605                b_prefix = o->a_prefix;
 606        } else {
 607                a_prefix = o->a_prefix;
 608                b_prefix = o->b_prefix;
 609        }
 610
 611        name_a += (*name_a == '/');
 612        name_b += (*name_b == '/');
 613        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 614        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 615
 616        strbuf_reset(&a_name);
 617        strbuf_reset(&b_name);
 618        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 619        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 620
 621        size_one = fill_textconv(textconv_one, one, &data_one);
 622        size_two = fill_textconv(textconv_two, two, &data_two);
 623
 624        memset(&ecbdata, 0, sizeof(ecbdata));
 625        ecbdata.color_diff = want_color(o->use_color);
 626        ecbdata.found_changesp = &o->found_changes;
 627        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 628        ecbdata.opt = o;
 629        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 630                mmfile_t mf1, mf2;
 631                mf1.ptr = (char *)data_one;
 632                mf2.ptr = (char *)data_two;
 633                mf1.size = size_one;
 634                mf2.size = size_two;
 635                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 636        }
 637        ecbdata.lno_in_preimage = 1;
 638        ecbdata.lno_in_postimage = 1;
 639
 640        lc_a = count_lines(data_one, size_one);
 641        lc_b = count_lines(data_two, size_two);
 642        fprintf(o->file,
 643                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 644                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 645                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 646                line_prefix, fraginfo);
 647        if (!o->irreversible_delete)
 648                print_line_count(o->file, lc_a);
 649        else
 650                fprintf(o->file, "?,?");
 651        fprintf(o->file, " +");
 652        print_line_count(o->file, lc_b);
 653        fprintf(o->file, " @@%s\n", reset);
 654        if (lc_a && !o->irreversible_delete)
 655                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 656        if (lc_b)
 657                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 658        if (textconv_one)
 659                free((char *)data_one);
 660        if (textconv_two)
 661                free((char *)data_two);
 662}
 663
 664struct diff_words_buffer {
 665        mmfile_t text;
 666        long alloc;
 667        struct diff_words_orig {
 668                const char *begin, *end;
 669        } *orig;
 670        int orig_nr, orig_alloc;
 671};
 672
 673static void diff_words_append(char *line, unsigned long len,
 674                struct diff_words_buffer *buffer)
 675{
 676        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 677        line++;
 678        len--;
 679        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 680        buffer->text.size += len;
 681        buffer->text.ptr[buffer->text.size] = '\0';
 682}
 683
 684struct diff_words_style_elem {
 685        const char *prefix;
 686        const char *suffix;
 687        const char *color; /* NULL; filled in by the setup code if
 688                            * color is enabled */
 689};
 690
 691struct diff_words_style {
 692        enum diff_words_type type;
 693        struct diff_words_style_elem new, old, ctx;
 694        const char *newline;
 695};
 696
 697static struct diff_words_style diff_words_styles[] = {
 698        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 699        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 700        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 701};
 702
 703struct diff_words_data {
 704        struct diff_words_buffer minus, plus;
 705        const char *current_plus;
 706        int last_minus;
 707        struct diff_options *opt;
 708        regex_t *word_regex;
 709        enum diff_words_type type;
 710        struct diff_words_style *style;
 711};
 712
 713static int fn_out_diff_words_write_helper(FILE *fp,
 714                                          struct diff_words_style_elem *st_el,
 715                                          const char *newline,
 716                                          size_t count, const char *buf,
 717                                          const char *line_prefix)
 718{
 719        int print = 0;
 720
 721        while (count) {
 722                char *p = memchr(buf, '\n', count);
 723                if (print)
 724                        fputs(line_prefix, fp);
 725                if (p != buf) {
 726                        if (st_el->color && fputs(st_el->color, fp) < 0)
 727                                return -1;
 728                        if (fputs(st_el->prefix, fp) < 0 ||
 729                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 730                            fputs(st_el->suffix, fp) < 0)
 731                                return -1;
 732                        if (st_el->color && *st_el->color
 733                            && fputs(GIT_COLOR_RESET, fp) < 0)
 734                                return -1;
 735                }
 736                if (!p)
 737                        return 0;
 738                if (fputs(newline, fp) < 0)
 739                        return -1;
 740                count -= p + 1 - buf;
 741                buf = p + 1;
 742                print = 1;
 743        }
 744        return 0;
 745}
 746
 747/*
 748 * '--color-words' algorithm can be described as:
 749 *
 750 *   1. collect a the minus/plus lines of a diff hunk, divided into
 751 *      minus-lines and plus-lines;
 752 *
 753 *   2. break both minus-lines and plus-lines into words and
 754 *      place them into two mmfile_t with one word for each line;
 755 *
 756 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 757 *
 758 * And for the common parts of the both file, we output the plus side text.
 759 * diff_words->current_plus is used to trace the current position of the plus file
 760 * which printed. diff_words->last_minus is used to trace the last minus word
 761 * printed.
 762 *
 763 * For '--graph' to work with '--color-words', we need to output the graph prefix
 764 * on each line of color words output. Generally, there are two conditions on
 765 * which we should output the prefix.
 766 *
 767 *   1. diff_words->last_minus == 0 &&
 768 *      diff_words->current_plus == diff_words->plus.text.ptr
 769 *
 770 *      that is: the plus text must start as a new line, and if there is no minus
 771 *      word printed, a graph prefix must be printed.
 772 *
 773 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 774 *      *(diff_words->current_plus - 1) == '\n'
 775 *
 776 *      that is: a graph prefix must be printed following a '\n'
 777 */
 778static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 779{
 780        if ((diff_words->last_minus == 0 &&
 781                diff_words->current_plus == diff_words->plus.text.ptr) ||
 782                (diff_words->current_plus > diff_words->plus.text.ptr &&
 783                *(diff_words->current_plus - 1) == '\n')) {
 784                return 1;
 785        } else {
 786                return 0;
 787        }
 788}
 789
 790static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 791{
 792        struct diff_words_data *diff_words = priv;
 793        struct diff_words_style *style = diff_words->style;
 794        int minus_first, minus_len, plus_first, plus_len;
 795        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 796        struct diff_options *opt = diff_words->opt;
 797        struct strbuf *msgbuf;
 798        char *line_prefix = "";
 799
 800        if (line[0] != '@' || parse_hunk_header(line, len,
 801                        &minus_first, &minus_len, &plus_first, &plus_len))
 802                return;
 803
 804        assert(opt);
 805        if (opt->output_prefix) {
 806                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 807                line_prefix = msgbuf->buf;
 808        }
 809
 810        /* POSIX requires that first be decremented by one if len == 0... */
 811        if (minus_len) {
 812                minus_begin = diff_words->minus.orig[minus_first].begin;
 813                minus_end =
 814                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 815        } else
 816                minus_begin = minus_end =
 817                        diff_words->minus.orig[minus_first].end;
 818
 819        if (plus_len) {
 820                plus_begin = diff_words->plus.orig[plus_first].begin;
 821                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 822        } else
 823                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 824
 825        if (color_words_output_graph_prefix(diff_words)) {
 826                fputs(line_prefix, diff_words->opt->file);
 827        }
 828        if (diff_words->current_plus != plus_begin) {
 829                fn_out_diff_words_write_helper(diff_words->opt->file,
 830                                &style->ctx, style->newline,
 831                                plus_begin - diff_words->current_plus,
 832                                diff_words->current_plus, line_prefix);
 833                if (*(plus_begin - 1) == '\n')
 834                        fputs(line_prefix, diff_words->opt->file);
 835        }
 836        if (minus_begin != minus_end) {
 837                fn_out_diff_words_write_helper(diff_words->opt->file,
 838                                &style->old, style->newline,
 839                                minus_end - minus_begin, minus_begin,
 840                                line_prefix);
 841        }
 842        if (plus_begin != plus_end) {
 843                fn_out_diff_words_write_helper(diff_words->opt->file,
 844                                &style->new, style->newline,
 845                                plus_end - plus_begin, plus_begin,
 846                                line_prefix);
 847        }
 848
 849        diff_words->current_plus = plus_end;
 850        diff_words->last_minus = minus_first;
 851}
 852
 853/* This function starts looking at *begin, and returns 0 iff a word was found. */
 854static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 855                int *begin, int *end)
 856{
 857        if (word_regex && *begin < buffer->size) {
 858                regmatch_t match[1];
 859                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 860                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 861                                        '\n', match[0].rm_eo - match[0].rm_so);
 862                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 863                        *begin += match[0].rm_so;
 864                        return *begin >= *end;
 865                }
 866                return -1;
 867        }
 868
 869        /* find the next word */
 870        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 871                (*begin)++;
 872        if (*begin >= buffer->size)
 873                return -1;
 874
 875        /* find the end of the word */
 876        *end = *begin + 1;
 877        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 878                (*end)++;
 879
 880        return 0;
 881}
 882
 883/*
 884 * This function splits the words in buffer->text, stores the list with
 885 * newline separator into out, and saves the offsets of the original words
 886 * in buffer->orig.
 887 */
 888static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 889                regex_t *word_regex)
 890{
 891        int i, j;
 892        long alloc = 0;
 893
 894        out->size = 0;
 895        out->ptr = NULL;
 896
 897        /* fake an empty "0th" word */
 898        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 899        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 900        buffer->orig_nr = 1;
 901
 902        for (i = 0; i < buffer->text.size; i++) {
 903                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 904                        return;
 905
 906                /* store original boundaries */
 907                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 908                                buffer->orig_alloc);
 909                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 910                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 911                buffer->orig_nr++;
 912
 913                /* store one word */
 914                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 915                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 916                out->ptr[out->size + j - i] = '\n';
 917                out->size += j - i + 1;
 918
 919                i = j - 1;
 920        }
 921}
 922
 923/* this executes the word diff on the accumulated buffers */
 924static void diff_words_show(struct diff_words_data *diff_words)
 925{
 926        xpparam_t xpp;
 927        xdemitconf_t xecfg;
 928        mmfile_t minus, plus;
 929        struct diff_words_style *style = diff_words->style;
 930
 931        struct diff_options *opt = diff_words->opt;
 932        struct strbuf *msgbuf;
 933        char *line_prefix = "";
 934
 935        assert(opt);
 936        if (opt->output_prefix) {
 937                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 938                line_prefix = msgbuf->buf;
 939        }
 940
 941        /* special case: only removal */
 942        if (!diff_words->plus.text.size) {
 943                fputs(line_prefix, diff_words->opt->file);
 944                fn_out_diff_words_write_helper(diff_words->opt->file,
 945                        &style->old, style->newline,
 946                        diff_words->minus.text.size,
 947                        diff_words->minus.text.ptr, line_prefix);
 948                diff_words->minus.text.size = 0;
 949                return;
 950        }
 951
 952        diff_words->current_plus = diff_words->plus.text.ptr;
 953        diff_words->last_minus = 0;
 954
 955        memset(&xpp, 0, sizeof(xpp));
 956        memset(&xecfg, 0, sizeof(xecfg));
 957        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 958        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 959        xpp.flags = 0;
 960        /* as only the hunk header will be parsed, we need a 0-context */
 961        xecfg.ctxlen = 0;
 962        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 963                      &xpp, &xecfg);
 964        free(minus.ptr);
 965        free(plus.ptr);
 966        if (diff_words->current_plus != diff_words->plus.text.ptr +
 967                        diff_words->plus.text.size) {
 968                if (color_words_output_graph_prefix(diff_words))
 969                        fputs(line_prefix, diff_words->opt->file);
 970                fn_out_diff_words_write_helper(diff_words->opt->file,
 971                        &style->ctx, style->newline,
 972                        diff_words->plus.text.ptr + diff_words->plus.text.size
 973                        - diff_words->current_plus, diff_words->current_plus,
 974                        line_prefix);
 975        }
 976        diff_words->minus.text.size = diff_words->plus.text.size = 0;
 977}
 978
 979/* In "color-words" mode, show word-diff of words accumulated in the buffer */
 980static void diff_words_flush(struct emit_callback *ecbdata)
 981{
 982        if (ecbdata->diff_words->minus.text.size ||
 983            ecbdata->diff_words->plus.text.size)
 984                diff_words_show(ecbdata->diff_words);
 985}
 986
 987static void free_diff_words_data(struct emit_callback *ecbdata)
 988{
 989        if (ecbdata->diff_words) {
 990                diff_words_flush(ecbdata);
 991                free (ecbdata->diff_words->minus.text.ptr);
 992                free (ecbdata->diff_words->minus.orig);
 993                free (ecbdata->diff_words->plus.text.ptr);
 994                free (ecbdata->diff_words->plus.orig);
 995                if (ecbdata->diff_words->word_regex) {
 996                        regfree(ecbdata->diff_words->word_regex);
 997                        free(ecbdata->diff_words->word_regex);
 998                }
 999                free(ecbdata->diff_words);
1000                ecbdata->diff_words = NULL;
1001        }
1002}
1003
1004const char *diff_get_color(int diff_use_color, enum color_diff ix)
1005{
1006        if (want_color(diff_use_color))
1007                return diff_colors[ix];
1008        return "";
1009}
1010
1011static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1012{
1013        const char *cp;
1014        unsigned long allot;
1015        size_t l = len;
1016
1017        if (ecb->truncate)
1018                return ecb->truncate(line, len);
1019        cp = line;
1020        allot = l;
1021        while (0 < l) {
1022                (void) utf8_width(&cp, &l);
1023                if (!cp)
1024                        break; /* truncated in the middle? */
1025        }
1026        return allot - l;
1027}
1028
1029static void find_lno(const char *line, struct emit_callback *ecbdata)
1030{
1031        const char *p;
1032        ecbdata->lno_in_preimage = 0;
1033        ecbdata->lno_in_postimage = 0;
1034        p = strchr(line, '-');
1035        if (!p)
1036                return; /* cannot happen */
1037        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1038        p = strchr(p, '+');
1039        if (!p)
1040                return; /* cannot happen */
1041        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1042}
1043
1044static void fn_out_consume(void *priv, char *line, unsigned long len)
1045{
1046        struct emit_callback *ecbdata = priv;
1047        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1048        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1049        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1050        struct diff_options *o = ecbdata->opt;
1051        char *line_prefix = "";
1052        struct strbuf *msgbuf;
1053
1054        if (o && o->output_prefix) {
1055                msgbuf = o->output_prefix(o, o->output_prefix_data);
1056                line_prefix = msgbuf->buf;
1057        }
1058
1059        if (ecbdata->header) {
1060                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1061                strbuf_reset(ecbdata->header);
1062                ecbdata->header = NULL;
1063        }
1064        *(ecbdata->found_changesp) = 1;
1065
1066        if (ecbdata->label_path[0]) {
1067                const char *name_a_tab, *name_b_tab;
1068
1069                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1070                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1071
1072                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1073                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1074                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1075                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1076                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1077        }
1078
1079        if (diff_suppress_blank_empty
1080            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1081                line[0] = '\n';
1082                len = 1;
1083        }
1084
1085        if (line[0] == '@') {
1086                if (ecbdata->diff_words)
1087                        diff_words_flush(ecbdata);
1088                len = sane_truncate_line(ecbdata, line, len);
1089                find_lno(line, ecbdata);
1090                emit_hunk_header(ecbdata, line, len);
1091                if (line[len-1] != '\n')
1092                        putc('\n', ecbdata->opt->file);
1093                return;
1094        }
1095
1096        if (len < 1) {
1097                emit_line(ecbdata->opt, reset, reset, line, len);
1098                if (ecbdata->diff_words
1099                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1100                        fputs("~\n", ecbdata->opt->file);
1101                return;
1102        }
1103
1104        if (ecbdata->diff_words) {
1105                if (line[0] == '-') {
1106                        diff_words_append(line, len,
1107                                          &ecbdata->diff_words->minus);
1108                        return;
1109                } else if (line[0] == '+') {
1110                        diff_words_append(line, len,
1111                                          &ecbdata->diff_words->plus);
1112                        return;
1113                }
1114                diff_words_flush(ecbdata);
1115                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1116                        emit_line(ecbdata->opt, plain, reset, line, len);
1117                        fputs("~\n", ecbdata->opt->file);
1118                } else {
1119                        /*
1120                         * Skip the prefix character, if any.  With
1121                         * diff_suppress_blank_empty, there may be
1122                         * none.
1123                         */
1124                        if (line[0] != '\n') {
1125                              line++;
1126                              len--;
1127                        }
1128                        emit_line(ecbdata->opt, plain, reset, line, len);
1129                }
1130                return;
1131        }
1132
1133        if (line[0] != '+') {
1134                const char *color =
1135                        diff_get_color(ecbdata->color_diff,
1136                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1137                ecbdata->lno_in_preimage++;
1138                if (line[0] == ' ')
1139                        ecbdata->lno_in_postimage++;
1140                emit_line(ecbdata->opt, color, reset, line, len);
1141        } else {
1142                ecbdata->lno_in_postimage++;
1143                emit_add_line(reset, ecbdata, line + 1, len - 1);
1144        }
1145}
1146
1147static char *pprint_rename(const char *a, const char *b)
1148{
1149        const char *old = a;
1150        const char *new = b;
1151        struct strbuf name = STRBUF_INIT;
1152        int pfx_length, sfx_length;
1153        int len_a = strlen(a);
1154        int len_b = strlen(b);
1155        int a_midlen, b_midlen;
1156        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1157        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1158
1159        if (qlen_a || qlen_b) {
1160                quote_c_style(a, &name, NULL, 0);
1161                strbuf_addstr(&name, " => ");
1162                quote_c_style(b, &name, NULL, 0);
1163                return strbuf_detach(&name, NULL);
1164        }
1165
1166        /* Find common prefix */
1167        pfx_length = 0;
1168        while (*old && *new && *old == *new) {
1169                if (*old == '/')
1170                        pfx_length = old - a + 1;
1171                old++;
1172                new++;
1173        }
1174
1175        /* Find common suffix */
1176        old = a + len_a;
1177        new = b + len_b;
1178        sfx_length = 0;
1179        while (a <= old && b <= new && *old == *new) {
1180                if (*old == '/')
1181                        sfx_length = len_a - (old - a);
1182                old--;
1183                new--;
1184        }
1185
1186        /*
1187         * pfx{mid-a => mid-b}sfx
1188         * {pfx-a => pfx-b}sfx
1189         * pfx{sfx-a => sfx-b}
1190         * name-a => name-b
1191         */
1192        a_midlen = len_a - pfx_length - sfx_length;
1193        b_midlen = len_b - pfx_length - sfx_length;
1194        if (a_midlen < 0)
1195                a_midlen = 0;
1196        if (b_midlen < 0)
1197                b_midlen = 0;
1198
1199        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1200        if (pfx_length + sfx_length) {
1201                strbuf_add(&name, a, pfx_length);
1202                strbuf_addch(&name, '{');
1203        }
1204        strbuf_add(&name, a + pfx_length, a_midlen);
1205        strbuf_addstr(&name, " => ");
1206        strbuf_add(&name, b + pfx_length, b_midlen);
1207        if (pfx_length + sfx_length) {
1208                strbuf_addch(&name, '}');
1209                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1210        }
1211        return strbuf_detach(&name, NULL);
1212}
1213
1214struct diffstat_t {
1215        int nr;
1216        int alloc;
1217        struct diffstat_file {
1218                char *from_name;
1219                char *name;
1220                char *print_name;
1221                unsigned is_unmerged:1;
1222                unsigned is_binary:1;
1223                unsigned is_renamed:1;
1224                uintmax_t added, deleted;
1225        } **files;
1226};
1227
1228static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1229                                          const char *name_a,
1230                                          const char *name_b)
1231{
1232        struct diffstat_file *x;
1233        x = xcalloc(sizeof (*x), 1);
1234        if (diffstat->nr == diffstat->alloc) {
1235                diffstat->alloc = alloc_nr(diffstat->alloc);
1236                diffstat->files = xrealloc(diffstat->files,
1237                                diffstat->alloc * sizeof(x));
1238        }
1239        diffstat->files[diffstat->nr++] = x;
1240        if (name_b) {
1241                x->from_name = xstrdup(name_a);
1242                x->name = xstrdup(name_b);
1243                x->is_renamed = 1;
1244        }
1245        else {
1246                x->from_name = NULL;
1247                x->name = xstrdup(name_a);
1248        }
1249        return x;
1250}
1251
1252static void diffstat_consume(void *priv, char *line, unsigned long len)
1253{
1254        struct diffstat_t *diffstat = priv;
1255        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1256
1257        if (line[0] == '+')
1258                x->added++;
1259        else if (line[0] == '-')
1260                x->deleted++;
1261}
1262
1263const char mime_boundary_leader[] = "------------";
1264
1265static int scale_linear(int it, int width, int max_change)
1266{
1267        /*
1268         * make sure that at least one '-' is printed if there were deletions,
1269         * and likewise for '+'.
1270         */
1271        if (max_change < 2)
1272                return it;
1273        return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
1274}
1275
1276static void show_name(FILE *file,
1277                      const char *prefix, const char *name, int len)
1278{
1279        fprintf(file, " %s%-*s |", prefix, len, name);
1280}
1281
1282static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1283{
1284        if (cnt <= 0)
1285                return;
1286        fprintf(file, "%s", set);
1287        while (cnt--)
1288                putc(ch, file);
1289        fprintf(file, "%s", reset);
1290}
1291
1292static void fill_print_name(struct diffstat_file *file)
1293{
1294        char *pname;
1295
1296        if (file->print_name)
1297                return;
1298
1299        if (!file->is_renamed) {
1300                struct strbuf buf = STRBUF_INIT;
1301                if (quote_c_style(file->name, &buf, NULL, 0)) {
1302                        pname = strbuf_detach(&buf, NULL);
1303                } else {
1304                        pname = file->name;
1305                        strbuf_release(&buf);
1306                }
1307        } else {
1308                pname = pprint_rename(file->from_name, file->name);
1309        }
1310        file->print_name = pname;
1311}
1312
1313static void show_stats(struct diffstat_t *data, struct diff_options *options)
1314{
1315        int i, len, add, del, adds = 0, dels = 0;
1316        uintmax_t max_change = 0, max_len = 0;
1317        int total_files = data->nr;
1318        int width, name_width;
1319        const char *reset, *add_c, *del_c;
1320        const char *line_prefix = "";
1321        struct strbuf *msg = NULL;
1322
1323        if (data->nr == 0)
1324                return;
1325
1326        if (options->output_prefix) {
1327                msg = options->output_prefix(options, options->output_prefix_data);
1328                line_prefix = msg->buf;
1329        }
1330
1331        width = options->stat_width ? options->stat_width : 80;
1332        name_width = options->stat_name_width ? options->stat_name_width : 50;
1333
1334        /* Sanity: give at least 5 columns to the graph,
1335         * but leave at least 10 columns for the name.
1336         */
1337        if (width < 25)
1338                width = 25;
1339        if (name_width < 10)
1340                name_width = 10;
1341        else if (width < name_width + 15)
1342                name_width = width - 15;
1343
1344        /* Find the longest filename and max number of changes */
1345        reset = diff_get_color_opt(options, DIFF_RESET);
1346        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1347        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1348
1349        for (i = 0; i < data->nr; i++) {
1350                struct diffstat_file *file = data->files[i];
1351                uintmax_t change = file->added + file->deleted;
1352                fill_print_name(file);
1353                len = strlen(file->print_name);
1354                if (max_len < len)
1355                        max_len = len;
1356
1357                if (file->is_binary || file->is_unmerged)
1358                        continue;
1359                if (max_change < change)
1360                        max_change = change;
1361        }
1362
1363        /* Compute the width of the graph part;
1364         * 10 is for one blank at the beginning of the line plus
1365         * " | count " between the name and the graph.
1366         *
1367         * From here on, name_width is the width of the name area,
1368         * and width is the width of the graph area.
1369         */
1370        name_width = (name_width < max_len) ? name_width : max_len;
1371        if (width < (name_width + 10) + max_change)
1372                width = width - (name_width + 10);
1373        else
1374                width = max_change;
1375
1376        for (i = 0; i < data->nr; i++) {
1377                const char *prefix = "";
1378                char *name = data->files[i]->print_name;
1379                uintmax_t added = data->files[i]->added;
1380                uintmax_t deleted = data->files[i]->deleted;
1381                int name_len;
1382
1383                /*
1384                 * "scale" the filename
1385                 */
1386                len = name_width;
1387                name_len = strlen(name);
1388                if (name_width < name_len) {
1389                        char *slash;
1390                        prefix = "...";
1391                        len -= 3;
1392                        name += name_len - len;
1393                        slash = strchr(name, '/');
1394                        if (slash)
1395                                name = slash;
1396                }
1397
1398                if (data->files[i]->is_binary) {
1399                        fprintf(options->file, "%s", line_prefix);
1400                        show_name(options->file, prefix, name, len);
1401                        fprintf(options->file, "  Bin ");
1402                        fprintf(options->file, "%s%"PRIuMAX"%s",
1403                                del_c, deleted, reset);
1404                        fprintf(options->file, " -> ");
1405                        fprintf(options->file, "%s%"PRIuMAX"%s",
1406                                add_c, added, reset);
1407                        fprintf(options->file, " bytes");
1408                        fprintf(options->file, "\n");
1409                        continue;
1410                }
1411                else if (data->files[i]->is_unmerged) {
1412                        fprintf(options->file, "%s", line_prefix);
1413                        show_name(options->file, prefix, name, len);
1414                        fprintf(options->file, "  Unmerged\n");
1415                        continue;
1416                }
1417                else if (!data->files[i]->is_renamed &&
1418                         (added + deleted == 0)) {
1419                        total_files--;
1420                        continue;
1421                }
1422
1423                /*
1424                 * scale the add/delete
1425                 */
1426                add = added;
1427                del = deleted;
1428                adds += add;
1429                dels += del;
1430
1431                if (width <= max_change) {
1432                        add = scale_linear(add, width, max_change);
1433                        del = scale_linear(del, width, max_change);
1434                }
1435                fprintf(options->file, "%s", line_prefix);
1436                show_name(options->file, prefix, name, len);
1437                fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
1438                                added + deleted ? " " : "");
1439                show_graph(options->file, '+', add, add_c, reset);
1440                show_graph(options->file, '-', del, del_c, reset);
1441                fprintf(options->file, "\n");
1442        }
1443        fprintf(options->file, "%s", line_prefix);
1444        fprintf(options->file,
1445               " %d files changed, %d insertions(+), %d deletions(-)\n",
1446               total_files, adds, dels);
1447}
1448
1449static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1450{
1451        int i, adds = 0, dels = 0, total_files = data->nr;
1452
1453        if (data->nr == 0)
1454                return;
1455
1456        for (i = 0; i < data->nr; i++) {
1457                if (!data->files[i]->is_binary &&
1458                    !data->files[i]->is_unmerged) {
1459                        int added = data->files[i]->added;
1460                        int deleted= data->files[i]->deleted;
1461                        if (!data->files[i]->is_renamed &&
1462                            (added + deleted == 0)) {
1463                                total_files--;
1464                        } else {
1465                                adds += added;
1466                                dels += deleted;
1467                        }
1468                }
1469        }
1470        if (options->output_prefix) {
1471                struct strbuf *msg = NULL;
1472                msg = options->output_prefix(options,
1473                                options->output_prefix_data);
1474                fprintf(options->file, "%s", msg->buf);
1475        }
1476        fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
1477               total_files, adds, dels);
1478}
1479
1480static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1481{
1482        int i;
1483
1484        if (data->nr == 0)
1485                return;
1486
1487        for (i = 0; i < data->nr; i++) {
1488                struct diffstat_file *file = data->files[i];
1489
1490                if (options->output_prefix) {
1491                        struct strbuf *msg = NULL;
1492                        msg = options->output_prefix(options,
1493                                        options->output_prefix_data);
1494                        fprintf(options->file, "%s", msg->buf);
1495                }
1496
1497                if (file->is_binary)
1498                        fprintf(options->file, "-\t-\t");
1499                else
1500                        fprintf(options->file,
1501                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1502                                file->added, file->deleted);
1503                if (options->line_termination) {
1504                        fill_print_name(file);
1505                        if (!file->is_renamed)
1506                                write_name_quoted(file->name, options->file,
1507                                                  options->line_termination);
1508                        else {
1509                                fputs(file->print_name, options->file);
1510                                putc(options->line_termination, options->file);
1511                        }
1512                } else {
1513                        if (file->is_renamed) {
1514                                putc('\0', options->file);
1515                                write_name_quoted(file->from_name, options->file, '\0');
1516                        }
1517                        write_name_quoted(file->name, options->file, '\0');
1518                }
1519        }
1520}
1521
1522struct dirstat_file {
1523        const char *name;
1524        unsigned long changed;
1525};
1526
1527struct dirstat_dir {
1528        struct dirstat_file *files;
1529        int alloc, nr, permille, cumulative;
1530};
1531
1532static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1533                unsigned long changed, const char *base, int baselen)
1534{
1535        unsigned long this_dir = 0;
1536        unsigned int sources = 0;
1537        const char *line_prefix = "";
1538        struct strbuf *msg = NULL;
1539
1540        if (opt->output_prefix) {
1541                msg = opt->output_prefix(opt, opt->output_prefix_data);
1542                line_prefix = msg->buf;
1543        }
1544
1545        while (dir->nr) {
1546                struct dirstat_file *f = dir->files;
1547                int namelen = strlen(f->name);
1548                unsigned long this;
1549                char *slash;
1550
1551                if (namelen < baselen)
1552                        break;
1553                if (memcmp(f->name, base, baselen))
1554                        break;
1555                slash = strchr(f->name + baselen, '/');
1556                if (slash) {
1557                        int newbaselen = slash + 1 - f->name;
1558                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1559                        sources++;
1560                } else {
1561                        this = f->changed;
1562                        dir->files++;
1563                        dir->nr--;
1564                        sources += 2;
1565                }
1566                this_dir += this;
1567        }
1568
1569        /*
1570         * We don't report dirstat's for
1571         *  - the top level
1572         *  - or cases where everything came from a single directory
1573         *    under this directory (sources == 1).
1574         */
1575        if (baselen && sources != 1) {
1576                if (this_dir) {
1577                        int permille = this_dir * 1000 / changed;
1578                        if (permille >= dir->permille) {
1579                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1580                                        permille / 10, permille % 10, baselen, base);
1581                                if (!dir->cumulative)
1582                                        return 0;
1583                        }
1584                }
1585        }
1586        return this_dir;
1587}
1588
1589static int dirstat_compare(const void *_a, const void *_b)
1590{
1591        const struct dirstat_file *a = _a;
1592        const struct dirstat_file *b = _b;
1593        return strcmp(a->name, b->name);
1594}
1595
1596static void show_dirstat(struct diff_options *options)
1597{
1598        int i;
1599        unsigned long changed;
1600        struct dirstat_dir dir;
1601        struct diff_queue_struct *q = &diff_queued_diff;
1602
1603        dir.files = NULL;
1604        dir.alloc = 0;
1605        dir.nr = 0;
1606        dir.permille = options->dirstat_permille;
1607        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1608
1609        changed = 0;
1610        for (i = 0; i < q->nr; i++) {
1611                struct diff_filepair *p = q->queue[i];
1612                const char *name;
1613                unsigned long copied, added, damage;
1614                int content_changed;
1615
1616                name = p->two->path ? p->two->path : p->one->path;
1617
1618                if (p->one->sha1_valid && p->two->sha1_valid)
1619                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1620                else
1621                        content_changed = 1;
1622
1623                if (!content_changed) {
1624                        /*
1625                         * The SHA1 has not changed, so pre-/post-content is
1626                         * identical. We can therefore skip looking at the
1627                         * file contents altogether.
1628                         */
1629                        damage = 0;
1630                        goto found_damage;
1631                }
1632
1633                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1634                        /*
1635                         * In --dirstat-by-file mode, we don't really need to
1636                         * look at the actual file contents at all.
1637                         * The fact that the SHA1 changed is enough for us to
1638                         * add this file to the list of results
1639                         * (with each file contributing equal damage).
1640                         */
1641                        damage = 1;
1642                        goto found_damage;
1643                }
1644
1645                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1646                        diff_populate_filespec(p->one, 0);
1647                        diff_populate_filespec(p->two, 0);
1648                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1649                                               &copied, &added);
1650                        diff_free_filespec_data(p->one);
1651                        diff_free_filespec_data(p->two);
1652                } else if (DIFF_FILE_VALID(p->one)) {
1653                        diff_populate_filespec(p->one, 1);
1654                        copied = added = 0;
1655                        diff_free_filespec_data(p->one);
1656                } else if (DIFF_FILE_VALID(p->two)) {
1657                        diff_populate_filespec(p->two, 1);
1658                        copied = 0;
1659                        added = p->two->size;
1660                        diff_free_filespec_data(p->two);
1661                } else
1662                        continue;
1663
1664                /*
1665                 * Original minus copied is the removed material,
1666                 * added is the new material.  They are both damages
1667                 * made to the preimage.
1668                 * If the resulting damage is zero, we know that
1669                 * diffcore_count_changes() considers the two entries to
1670                 * be identical, but since content_changed is true, we
1671                 * know that there must have been _some_ kind of change,
1672                 * so we force all entries to have damage > 0.
1673                 */
1674                damage = (p->one->size - copied) + added;
1675                if (!damage)
1676                        damage = 1;
1677
1678found_damage:
1679                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1680                dir.files[dir.nr].name = name;
1681                dir.files[dir.nr].changed = damage;
1682                changed += damage;
1683                dir.nr++;
1684        }
1685
1686        /* This can happen even with many files, if everything was renames */
1687        if (!changed)
1688                return;
1689
1690        /* Show all directories with more than x% of the changes */
1691        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1692        gather_dirstat(options, &dir, changed, "", 0);
1693}
1694
1695static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1696{
1697        int i;
1698        unsigned long changed;
1699        struct dirstat_dir dir;
1700
1701        if (data->nr == 0)
1702                return;
1703
1704        dir.files = NULL;
1705        dir.alloc = 0;
1706        dir.nr = 0;
1707        dir.permille = options->dirstat_permille;
1708        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1709
1710        changed = 0;
1711        for (i = 0; i < data->nr; i++) {
1712                struct diffstat_file *file = data->files[i];
1713                unsigned long damage = file->added + file->deleted;
1714                if (file->is_binary)
1715                        /*
1716                         * binary files counts bytes, not lines. Must find some
1717                         * way to normalize binary bytes vs. textual lines.
1718                         * The following heuristic assumes that there are 64
1719                         * bytes per "line".
1720                         * This is stupid and ugly, but very cheap...
1721                         */
1722                        damage = (damage + 63) / 64;
1723                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1724                dir.files[dir.nr].name = file->name;
1725                dir.files[dir.nr].changed = damage;
1726                changed += damage;
1727                dir.nr++;
1728        }
1729
1730        /* This can happen even with many files, if everything was renames */
1731        if (!changed)
1732                return;
1733
1734        /* Show all directories with more than x% of the changes */
1735        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1736        gather_dirstat(options, &dir, changed, "", 0);
1737}
1738
1739static void free_diffstat_info(struct diffstat_t *diffstat)
1740{
1741        int i;
1742        for (i = 0; i < diffstat->nr; i++) {
1743                struct diffstat_file *f = diffstat->files[i];
1744                if (f->name != f->print_name)
1745                        free(f->print_name);
1746                free(f->name);
1747                free(f->from_name);
1748                free(f);
1749        }
1750        free(diffstat->files);
1751}
1752
1753struct checkdiff_t {
1754        const char *filename;
1755        int lineno;
1756        int conflict_marker_size;
1757        struct diff_options *o;
1758        unsigned ws_rule;
1759        unsigned status;
1760};
1761
1762static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
1763{
1764        char firstchar;
1765        int cnt;
1766
1767        if (len < marker_size + 1)
1768                return 0;
1769        firstchar = line[0];
1770        switch (firstchar) {
1771        case '=': case '>': case '<': case '|':
1772                break;
1773        default:
1774                return 0;
1775        }
1776        for (cnt = 1; cnt < marker_size; cnt++)
1777                if (line[cnt] != firstchar)
1778                        return 0;
1779        /* line[1] thru line[marker_size-1] are same as firstchar */
1780        if (len < marker_size + 1 || !isspace(line[marker_size]))
1781                return 0;
1782        return 1;
1783}
1784
1785static void checkdiff_consume(void *priv, char *line, unsigned long len)
1786{
1787        struct checkdiff_t *data = priv;
1788        int marker_size = data->conflict_marker_size;
1789        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
1790        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
1791        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
1792        char *err;
1793        char *line_prefix = "";
1794        struct strbuf *msgbuf;
1795
1796        assert(data->o);
1797        if (data->o->output_prefix) {
1798                msgbuf = data->o->output_prefix(data->o,
1799                        data->o->output_prefix_data);
1800                line_prefix = msgbuf->buf;
1801        }
1802
1803        if (line[0] == '+') {
1804                unsigned bad;
1805                data->lineno++;
1806                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
1807                        data->status |= 1;
1808                        fprintf(data->o->file,
1809                                "%s%s:%d: leftover conflict marker\n",
1810                                line_prefix, data->filename, data->lineno);
1811                }
1812                bad = ws_check(line + 1, len - 1, data->ws_rule);
1813                if (!bad)
1814                        return;
1815                data->status |= bad;
1816                err = whitespace_error_string(bad);
1817                fprintf(data->o->file, "%s%s:%d: %s.\n",
1818                        line_prefix, data->filename, data->lineno, err);
1819                free(err);
1820                emit_line(data->o, set, reset, line, 1);
1821                ws_check_emit(line + 1, len - 1, data->ws_rule,
1822                              data->o->file, set, reset, ws);
1823        } else if (line[0] == ' ') {
1824                data->lineno++;
1825        } else if (line[0] == '@') {
1826                char *plus = strchr(line, '+');
1827                if (plus)
1828                        data->lineno = strtol(plus, NULL, 10) - 1;
1829                else
1830                        die("invalid diff");
1831        }
1832}
1833
1834static unsigned char *deflate_it(char *data,
1835                                 unsigned long size,
1836                                 unsigned long *result_size)
1837{
1838        int bound;
1839        unsigned char *deflated;
1840        git_zstream stream;
1841
1842        memset(&stream, 0, sizeof(stream));
1843        git_deflate_init(&stream, zlib_compression_level);
1844        bound = git_deflate_bound(&stream, size);
1845        deflated = xmalloc(bound);
1846        stream.next_out = deflated;
1847        stream.avail_out = bound;
1848
1849        stream.next_in = (unsigned char *)data;
1850        stream.avail_in = size;
1851        while (git_deflate(&stream, Z_FINISH) == Z_OK)
1852                ; /* nothing */
1853        git_deflate_end(&stream);
1854        *result_size = stream.total_out;
1855        return deflated;
1856}
1857
1858static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1859{
1860        void *cp;
1861        void *delta;
1862        void *deflated;
1863        void *data;
1864        unsigned long orig_size;
1865        unsigned long delta_size;
1866        unsigned long deflate_size;
1867        unsigned long data_size;
1868
1869        /* We could do deflated delta, or we could do just deflated two,
1870         * whichever is smaller.
1871         */
1872        delta = NULL;
1873        deflated = deflate_it(two->ptr, two->size, &deflate_size);
1874        if (one->size && two->size) {
1875                delta = diff_delta(one->ptr, one->size,
1876                                   two->ptr, two->size,
1877                                   &delta_size, deflate_size);
1878                if (delta) {
1879                        void *to_free = delta;
1880                        orig_size = delta_size;
1881                        delta = deflate_it(delta, delta_size, &delta_size);
1882                        free(to_free);
1883                }
1884        }
1885
1886        if (delta && delta_size < deflate_size) {
1887                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
1888                free(deflated);
1889                data = delta;
1890                data_size = delta_size;
1891        }
1892        else {
1893                fprintf(file, "%sliteral %lu\n", prefix, two->size);
1894                free(delta);
1895                data = deflated;
1896                data_size = deflate_size;
1897        }
1898
1899        /* emit data encoded in base85 */
1900        cp = data;
1901        while (data_size) {
1902                int bytes = (52 < data_size) ? 52 : data_size;
1903                char line[70];
1904                data_size -= bytes;
1905                if (bytes <= 26)
1906                        line[0] = bytes + 'A' - 1;
1907                else
1908                        line[0] = bytes - 26 + 'a' - 1;
1909                encode_85(line + 1, cp, bytes);
1910                cp = (char *) cp + bytes;
1911                fprintf(file, "%s", prefix);
1912                fputs(line, file);
1913                fputc('\n', file);
1914        }
1915        fprintf(file, "%s\n", prefix);
1916        free(data);
1917}
1918
1919static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1920{
1921        fprintf(file, "%sGIT binary patch\n", prefix);
1922        emit_binary_diff_body(file, one, two, prefix);
1923        emit_binary_diff_body(file, two, one, prefix);
1924}
1925
1926static void diff_filespec_load_driver(struct diff_filespec *one)
1927{
1928        /* Use already-loaded driver */
1929        if (one->driver)
1930                return;
1931
1932        if (S_ISREG(one->mode))
1933                one->driver = userdiff_find_by_path(one->path);
1934
1935        /* Fallback to default settings */
1936        if (!one->driver)
1937                one->driver = userdiff_find_by_name("default");
1938}
1939
1940int diff_filespec_is_binary(struct diff_filespec *one)
1941{
1942        if (one->is_binary == -1) {
1943                diff_filespec_load_driver(one);
1944                if (one->driver->binary != -1)
1945                        one->is_binary = one->driver->binary;
1946                else {
1947                        if (!one->data && DIFF_FILE_VALID(one))
1948                                diff_populate_filespec(one, 0);
1949                        if (one->data)
1950                                one->is_binary = buffer_is_binary(one->data,
1951                                                one->size);
1952                        if (one->is_binary == -1)
1953                                one->is_binary = 0;
1954                }
1955        }
1956        return one->is_binary;
1957}
1958
1959static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
1960{
1961        diff_filespec_load_driver(one);
1962        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
1963}
1964
1965static const char *userdiff_word_regex(struct diff_filespec *one)
1966{
1967        diff_filespec_load_driver(one);
1968        return one->driver->word_regex;
1969}
1970
1971void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
1972{
1973        if (!options->a_prefix)
1974                options->a_prefix = a;
1975        if (!options->b_prefix)
1976                options->b_prefix = b;
1977}
1978
1979struct userdiff_driver *get_textconv(struct diff_filespec *one)
1980{
1981        if (!DIFF_FILE_VALID(one))
1982                return NULL;
1983
1984        diff_filespec_load_driver(one);
1985        return userdiff_get_textconv(one->driver);
1986}
1987
1988static void builtin_diff(const char *name_a,
1989                         const char *name_b,
1990                         struct diff_filespec *one,
1991                         struct diff_filespec *two,
1992                         const char *xfrm_msg,
1993                         int must_show_header,
1994                         struct diff_options *o,
1995                         int complete_rewrite)
1996{
1997        mmfile_t mf1, mf2;
1998        const char *lbl[2];
1999        char *a_one, *b_two;
2000        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
2001        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2002        const char *a_prefix, *b_prefix;
2003        struct userdiff_driver *textconv_one = NULL;
2004        struct userdiff_driver *textconv_two = NULL;
2005        struct strbuf header = STRBUF_INIT;
2006        struct strbuf *msgbuf;
2007        char *line_prefix = "";
2008
2009        if (o->output_prefix) {
2010                msgbuf = o->output_prefix(o, o->output_prefix_data);
2011                line_prefix = msgbuf->buf;
2012        }
2013
2014        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2015                        (!one->mode || S_ISGITLINK(one->mode)) &&
2016                        (!two->mode || S_ISGITLINK(two->mode))) {
2017                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2018                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2019                show_submodule_summary(o->file, one ? one->path : two->path,
2020                                one->sha1, two->sha1, two->dirty_submodule,
2021                                del, add, reset);
2022                return;
2023        }
2024
2025        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2026                textconv_one = get_textconv(one);
2027                textconv_two = get_textconv(two);
2028        }
2029
2030        diff_set_mnemonic_prefix(o, "a/", "b/");
2031        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2032                a_prefix = o->b_prefix;
2033                b_prefix = o->a_prefix;
2034        } else {
2035                a_prefix = o->a_prefix;
2036                b_prefix = o->b_prefix;
2037        }
2038
2039        /* Never use a non-valid filename anywhere if at all possible */
2040        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2041        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2042
2043        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2044        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2045        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2046        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2047        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
2048        if (lbl[0][0] == '/') {
2049                /* /dev/null */
2050                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
2051                if (xfrm_msg)
2052                        strbuf_addstr(&header, xfrm_msg);
2053                must_show_header = 1;
2054        }
2055        else if (lbl[1][0] == '/') {
2056                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
2057                if (xfrm_msg)
2058                        strbuf_addstr(&header, xfrm_msg);
2059                must_show_header = 1;
2060        }
2061        else {
2062                if (one->mode != two->mode) {
2063                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
2064                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
2065                        must_show_header = 1;
2066                }
2067                if (xfrm_msg)
2068                        strbuf_addstr(&header, xfrm_msg);
2069
2070                /*
2071                 * we do not run diff between different kind
2072                 * of objects.
2073                 */
2074                if ((one->mode ^ two->mode) & S_IFMT)
2075                        goto free_ab_and_return;
2076                if (complete_rewrite &&
2077                    (textconv_one || !diff_filespec_is_binary(one)) &&
2078                    (textconv_two || !diff_filespec_is_binary(two))) {
2079                        fprintf(o->file, "%s", header.buf);
2080                        strbuf_reset(&header);
2081                        emit_rewrite_diff(name_a, name_b, one, two,
2082                                                textconv_one, textconv_two, o);
2083                        o->found_changes = 1;
2084                        goto free_ab_and_return;
2085                }
2086        }
2087
2088        if (o->irreversible_delete && lbl[1][0] == '/') {
2089                fprintf(o->file, "%s", header.buf);
2090                strbuf_reset(&header);
2091                goto free_ab_and_return;
2092        } else if (!DIFF_OPT_TST(o, TEXT) &&
2093            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2094              (!textconv_two && diff_filespec_is_binary(two)) )) {
2095                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2096                        die("unable to read files to diff");
2097                /* Quite common confusing case */
2098                if (mf1.size == mf2.size &&
2099                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2100                        if (must_show_header)
2101                                fprintf(o->file, "%s", header.buf);
2102                        goto free_ab_and_return;
2103                }
2104                fprintf(o->file, "%s", header.buf);
2105                strbuf_reset(&header);
2106                if (DIFF_OPT_TST(o, BINARY))
2107                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2108                else
2109                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2110                                line_prefix, lbl[0], lbl[1]);
2111                o->found_changes = 1;
2112        } else {
2113                /* Crazy xdl interfaces.. */
2114                const char *diffopts = getenv("GIT_DIFF_OPTS");
2115                xpparam_t xpp;
2116                xdemitconf_t xecfg;
2117                struct emit_callback ecbdata;
2118                const struct userdiff_funcname *pe;
2119
2120                if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
2121                        fprintf(o->file, "%s", header.buf);
2122                        strbuf_reset(&header);
2123                }
2124
2125                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2126                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2127
2128                pe = diff_funcname_pattern(one);
2129                if (!pe)
2130                        pe = diff_funcname_pattern(two);
2131
2132                memset(&xpp, 0, sizeof(xpp));
2133                memset(&xecfg, 0, sizeof(xecfg));
2134                memset(&ecbdata, 0, sizeof(ecbdata));
2135                ecbdata.label_path = lbl;
2136                ecbdata.color_diff = want_color(o->use_color);
2137                ecbdata.found_changesp = &o->found_changes;
2138                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2139                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2140                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2141                ecbdata.opt = o;
2142                ecbdata.header = header.len ? &header : NULL;
2143                xpp.flags = o->xdl_opts;
2144                xecfg.ctxlen = o->context;
2145                xecfg.interhunkctxlen = o->interhunkcontext;
2146                xecfg.flags = XDL_EMIT_FUNCNAMES;
2147                if (pe)
2148                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2149                if (!diffopts)
2150                        ;
2151                else if (!prefixcmp(diffopts, "--unified="))
2152                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2153                else if (!prefixcmp(diffopts, "-u"))
2154                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2155                if (o->word_diff) {
2156                        int i;
2157
2158                        ecbdata.diff_words =
2159                                xcalloc(1, sizeof(struct diff_words_data));
2160                        ecbdata.diff_words->type = o->word_diff;
2161                        ecbdata.diff_words->opt = o;
2162                        if (!o->word_regex)
2163                                o->word_regex = userdiff_word_regex(one);
2164                        if (!o->word_regex)
2165                                o->word_regex = userdiff_word_regex(two);
2166                        if (!o->word_regex)
2167                                o->word_regex = diff_word_regex_cfg;
2168                        if (o->word_regex) {
2169                                ecbdata.diff_words->word_regex = (regex_t *)
2170                                        xmalloc(sizeof(regex_t));
2171                                if (regcomp(ecbdata.diff_words->word_regex,
2172                                                o->word_regex,
2173                                                REG_EXTENDED | REG_NEWLINE))
2174                                        die ("Invalid regular expression: %s",
2175                                                        o->word_regex);
2176                        }
2177                        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2178                                if (o->word_diff == diff_words_styles[i].type) {
2179                                        ecbdata.diff_words->style =
2180                                                &diff_words_styles[i];
2181                                        break;
2182                                }
2183                        }
2184                        if (want_color(o->use_color)) {
2185                                struct diff_words_style *st = ecbdata.diff_words->style;
2186                                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2187                                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2188                                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
2189                        }
2190                }
2191                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2192                              &xpp, &xecfg);
2193                if (o->word_diff)
2194                        free_diff_words_data(&ecbdata);
2195                if (textconv_one)
2196                        free(mf1.ptr);
2197                if (textconv_two)
2198                        free(mf2.ptr);
2199                xdiff_clear_find_func(&xecfg);
2200        }
2201
2202 free_ab_and_return:
2203        strbuf_release(&header);
2204        diff_free_filespec_data(one);
2205        diff_free_filespec_data(two);
2206        free(a_one);
2207        free(b_two);
2208        return;
2209}
2210
2211static void builtin_diffstat(const char *name_a, const char *name_b,
2212                             struct diff_filespec *one,
2213                             struct diff_filespec *two,
2214                             struct diffstat_t *diffstat,
2215                             struct diff_options *o,
2216                             int complete_rewrite)
2217{
2218        mmfile_t mf1, mf2;
2219        struct diffstat_file *data;
2220
2221        data = diffstat_add(diffstat, name_a, name_b);
2222
2223        if (!one || !two) {
2224                data->is_unmerged = 1;
2225                return;
2226        }
2227
2228        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2229                data->is_binary = 1;
2230                data->added = diff_filespec_size(two);
2231                data->deleted = diff_filespec_size(one);
2232        }
2233
2234        else if (complete_rewrite) {
2235                diff_populate_filespec(one, 0);
2236                diff_populate_filespec(two, 0);
2237                data->deleted = count_lines(one->data, one->size);
2238                data->added = count_lines(two->data, two->size);
2239        }
2240
2241        else {
2242                /* Crazy xdl interfaces.. */
2243                xpparam_t xpp;
2244                xdemitconf_t xecfg;
2245
2246                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2247                        die("unable to read files to diff");
2248
2249                memset(&xpp, 0, sizeof(xpp));
2250                memset(&xecfg, 0, sizeof(xecfg));
2251                xpp.flags = o->xdl_opts;
2252                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2253                              &xpp, &xecfg);
2254        }
2255
2256        diff_free_filespec_data(one);
2257        diff_free_filespec_data(two);
2258}
2259
2260static void builtin_checkdiff(const char *name_a, const char *name_b,
2261                              const char *attr_path,
2262                              struct diff_filespec *one,
2263                              struct diff_filespec *two,
2264                              struct diff_options *o)
2265{
2266        mmfile_t mf1, mf2;
2267        struct checkdiff_t data;
2268
2269        if (!two)
2270                return;
2271
2272        memset(&data, 0, sizeof(data));
2273        data.filename = name_b ? name_b : name_a;
2274        data.lineno = 0;
2275        data.o = o;
2276        data.ws_rule = whitespace_rule(attr_path);
2277        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2278
2279        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2280                die("unable to read files to diff");
2281
2282        /*
2283         * All the other codepaths check both sides, but not checking
2284         * the "old" side here is deliberate.  We are checking the newly
2285         * introduced changes, and as long as the "new" side is text, we
2286         * can and should check what it introduces.
2287         */
2288        if (diff_filespec_is_binary(two))
2289                goto free_and_return;
2290        else {
2291                /* Crazy xdl interfaces.. */
2292                xpparam_t xpp;
2293                xdemitconf_t xecfg;
2294
2295                memset(&xpp, 0, sizeof(xpp));
2296                memset(&xecfg, 0, sizeof(xecfg));
2297                xecfg.ctxlen = 1; /* at least one context line */
2298                xpp.flags = 0;
2299                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2300                              &xpp, &xecfg);
2301
2302                if (data.ws_rule & WS_BLANK_AT_EOF) {
2303                        struct emit_callback ecbdata;
2304                        int blank_at_eof;
2305
2306                        ecbdata.ws_rule = data.ws_rule;
2307                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2308                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2309
2310                        if (blank_at_eof) {
2311                                static char *err;
2312                                if (!err)
2313                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2314                                fprintf(o->file, "%s:%d: %s.\n",
2315                                        data.filename, blank_at_eof, err);
2316                                data.status = 1; /* report errors */
2317                        }
2318                }
2319        }
2320 free_and_return:
2321        diff_free_filespec_data(one);
2322        diff_free_filespec_data(two);
2323        if (data.status)
2324                DIFF_OPT_SET(o, CHECK_FAILED);
2325}
2326
2327struct diff_filespec *alloc_filespec(const char *path)
2328{
2329        int namelen = strlen(path);
2330        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2331
2332        memset(spec, 0, sizeof(*spec));
2333        spec->path = (char *)(spec + 1);
2334        memcpy(spec->path, path, namelen+1);
2335        spec->count = 1;
2336        spec->is_binary = -1;
2337        return spec;
2338}
2339
2340void free_filespec(struct diff_filespec *spec)
2341{
2342        if (!--spec->count) {
2343                diff_free_filespec_data(spec);
2344                free(spec);
2345        }
2346}
2347
2348void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2349                   unsigned short mode)
2350{
2351        if (mode) {
2352                spec->mode = canon_mode(mode);
2353                hashcpy(spec->sha1, sha1);
2354                spec->sha1_valid = !is_null_sha1(sha1);
2355        }
2356}
2357
2358/*
2359 * Given a name and sha1 pair, if the index tells us the file in
2360 * the work tree has that object contents, return true, so that
2361 * prepare_temp_file() does not have to inflate and extract.
2362 */
2363static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2364{
2365        struct cache_entry *ce;
2366        struct stat st;
2367        int pos, len;
2368
2369        /*
2370         * We do not read the cache ourselves here, because the
2371         * benchmark with my previous version that always reads cache
2372         * shows that it makes things worse for diff-tree comparing
2373         * two linux-2.6 kernel trees in an already checked out work
2374         * tree.  This is because most diff-tree comparisons deal with
2375         * only a small number of files, while reading the cache is
2376         * expensive for a large project, and its cost outweighs the
2377         * savings we get by not inflating the object to a temporary
2378         * file.  Practically, this code only helps when we are used
2379         * by diff-cache --cached, which does read the cache before
2380         * calling us.
2381         */
2382        if (!active_cache)
2383                return 0;
2384
2385        /* We want to avoid the working directory if our caller
2386         * doesn't need the data in a normal file, this system
2387         * is rather slow with its stat/open/mmap/close syscalls,
2388         * and the object is contained in a pack file.  The pack
2389         * is probably already open and will be faster to obtain
2390         * the data through than the working directory.  Loose
2391         * objects however would tend to be slower as they need
2392         * to be individually opened and inflated.
2393         */
2394        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2395                return 0;
2396
2397        len = strlen(name);
2398        pos = cache_name_pos(name, len);
2399        if (pos < 0)
2400                return 0;
2401        ce = active_cache[pos];
2402
2403        /*
2404         * This is not the sha1 we are looking for, or
2405         * unreusable because it is not a regular file.
2406         */
2407        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2408                return 0;
2409
2410        /*
2411         * If ce is marked as "assume unchanged", there is no
2412         * guarantee that work tree matches what we are looking for.
2413         */
2414        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2415                return 0;
2416
2417        /*
2418         * If ce matches the file in the work tree, we can reuse it.
2419         */
2420        if (ce_uptodate(ce) ||
2421            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2422                return 1;
2423
2424        return 0;
2425}
2426
2427static int populate_from_stdin(struct diff_filespec *s)
2428{
2429        struct strbuf buf = STRBUF_INIT;
2430        size_t size = 0;
2431
2432        if (strbuf_read(&buf, 0, 0) < 0)
2433                return error("error while reading from stdin %s",
2434                                     strerror(errno));
2435
2436        s->should_munmap = 0;
2437        s->data = strbuf_detach(&buf, &size);
2438        s->size = size;
2439        s->should_free = 1;
2440        return 0;
2441}
2442
2443static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2444{
2445        int len;
2446        char *data = xmalloc(100), *dirty = "";
2447
2448        /* Are we looking at the work tree? */
2449        if (s->dirty_submodule)
2450                dirty = "-dirty";
2451
2452        len = snprintf(data, 100,
2453                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2454        s->data = data;
2455        s->size = len;
2456        s->should_free = 1;
2457        if (size_only) {
2458                s->data = NULL;
2459                free(data);
2460        }
2461        return 0;
2462}
2463
2464/*
2465 * While doing rename detection and pickaxe operation, we may need to
2466 * grab the data for the blob (or file) for our own in-core comparison.
2467 * diff_filespec has data and size fields for this purpose.
2468 */
2469int diff_populate_filespec(struct diff_filespec *s, int size_only)
2470{
2471        int err = 0;
2472        if (!DIFF_FILE_VALID(s))
2473                die("internal error: asking to populate invalid file.");
2474        if (S_ISDIR(s->mode))
2475                return -1;
2476
2477        if (s->data)
2478                return 0;
2479
2480        if (size_only && 0 < s->size)
2481                return 0;
2482
2483        if (S_ISGITLINK(s->mode))
2484                return diff_populate_gitlink(s, size_only);
2485
2486        if (!s->sha1_valid ||
2487            reuse_worktree_file(s->path, s->sha1, 0)) {
2488                struct strbuf buf = STRBUF_INIT;
2489                struct stat st;
2490                int fd;
2491
2492                if (!strcmp(s->path, "-"))
2493                        return populate_from_stdin(s);
2494
2495                if (lstat(s->path, &st) < 0) {
2496                        if (errno == ENOENT) {
2497                        err_empty:
2498                                err = -1;
2499                        empty:
2500                                s->data = (char *)"";
2501                                s->size = 0;
2502                                return err;
2503                        }
2504                }
2505                s->size = xsize_t(st.st_size);
2506                if (!s->size)
2507                        goto empty;
2508                if (S_ISLNK(st.st_mode)) {
2509                        struct strbuf sb = STRBUF_INIT;
2510
2511                        if (strbuf_readlink(&sb, s->path, s->size))
2512                                goto err_empty;
2513                        s->size = sb.len;
2514                        s->data = strbuf_detach(&sb, NULL);
2515                        s->should_free = 1;
2516                        return 0;
2517                }
2518                if (size_only)
2519                        return 0;
2520                fd = open(s->path, O_RDONLY);
2521                if (fd < 0)
2522                        goto err_empty;
2523                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2524                close(fd);
2525                s->should_munmap = 1;
2526
2527                /*
2528                 * Convert from working tree format to canonical git format
2529                 */
2530                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2531                        size_t size = 0;
2532                        munmap(s->data, s->size);
2533                        s->should_munmap = 0;
2534                        s->data = strbuf_detach(&buf, &size);
2535                        s->size = size;
2536                        s->should_free = 1;
2537                }
2538        }
2539        else {
2540                enum object_type type;
2541                if (size_only) {
2542                        type = sha1_object_info(s->sha1, &s->size);
2543                        if (type < 0)
2544                                die("unable to read %s", sha1_to_hex(s->sha1));
2545                } else {
2546                        s->data = read_sha1_file(s->sha1, &type, &s->size);
2547                        if (!s->data)
2548                                die("unable to read %s", sha1_to_hex(s->sha1));
2549                        s->should_free = 1;
2550                }
2551        }
2552        return 0;
2553}
2554
2555void diff_free_filespec_blob(struct diff_filespec *s)
2556{
2557        if (s->should_free)
2558                free(s->data);
2559        else if (s->should_munmap)
2560                munmap(s->data, s->size);
2561
2562        if (s->should_free || s->should_munmap) {
2563                s->should_free = s->should_munmap = 0;
2564                s->data = NULL;
2565        }
2566}
2567
2568void diff_free_filespec_data(struct diff_filespec *s)
2569{
2570        diff_free_filespec_blob(s);
2571        free(s->cnt_data);
2572        s->cnt_data = NULL;
2573}
2574
2575static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2576                           void *blob,
2577                           unsigned long size,
2578                           const unsigned char *sha1,
2579                           int mode)
2580{
2581        int fd;
2582        struct strbuf buf = STRBUF_INIT;
2583        struct strbuf template = STRBUF_INIT;
2584        char *path_dup = xstrdup(path);
2585        const char *base = basename(path_dup);
2586
2587        /* Generate "XXXXXX_basename.ext" */
2588        strbuf_addstr(&template, "XXXXXX_");
2589        strbuf_addstr(&template, base);
2590
2591        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2592                        strlen(base) + 1);
2593        if (fd < 0)
2594                die_errno("unable to create temp-file");
2595        if (convert_to_working_tree(path,
2596                        (const char *)blob, (size_t)size, &buf)) {
2597                blob = buf.buf;
2598                size = buf.len;
2599        }
2600        if (write_in_full(fd, blob, size) != size)
2601                die_errno("unable to write temp-file");
2602        close(fd);
2603        temp->name = temp->tmp_path;
2604        strcpy(temp->hex, sha1_to_hex(sha1));
2605        temp->hex[40] = 0;
2606        sprintf(temp->mode, "%06o", mode);
2607        strbuf_release(&buf);
2608        strbuf_release(&template);
2609        free(path_dup);
2610}
2611
2612static struct diff_tempfile *prepare_temp_file(const char *name,
2613                struct diff_filespec *one)
2614{
2615        struct diff_tempfile *temp = claim_diff_tempfile();
2616
2617        if (!DIFF_FILE_VALID(one)) {
2618        not_a_valid_file:
2619                /* A '-' entry produces this for file-2, and
2620                 * a '+' entry produces this for file-1.
2621                 */
2622                temp->name = "/dev/null";
2623                strcpy(temp->hex, ".");
2624                strcpy(temp->mode, ".");
2625                return temp;
2626        }
2627
2628        if (!remove_tempfile_installed) {
2629                atexit(remove_tempfile);
2630                sigchain_push_common(remove_tempfile_on_signal);
2631                remove_tempfile_installed = 1;
2632        }
2633
2634        if (!one->sha1_valid ||
2635            reuse_worktree_file(name, one->sha1, 1)) {
2636                struct stat st;
2637                if (lstat(name, &st) < 0) {
2638                        if (errno == ENOENT)
2639                                goto not_a_valid_file;
2640                        die_errno("stat(%s)", name);
2641                }
2642                if (S_ISLNK(st.st_mode)) {
2643                        struct strbuf sb = STRBUF_INIT;
2644                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2645                                die_errno("readlink(%s)", name);
2646                        prep_temp_blob(name, temp, sb.buf, sb.len,
2647                                       (one->sha1_valid ?
2648                                        one->sha1 : null_sha1),
2649                                       (one->sha1_valid ?
2650                                        one->mode : S_IFLNK));
2651                        strbuf_release(&sb);
2652                }
2653                else {
2654                        /* we can borrow from the file in the work tree */
2655                        temp->name = name;
2656                        if (!one->sha1_valid)
2657                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2658                        else
2659                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2660                        /* Even though we may sometimes borrow the
2661                         * contents from the work tree, we always want
2662                         * one->mode.  mode is trustworthy even when
2663                         * !(one->sha1_valid), as long as
2664                         * DIFF_FILE_VALID(one).
2665                         */
2666                        sprintf(temp->mode, "%06o", one->mode);
2667                }
2668                return temp;
2669        }
2670        else {
2671                if (diff_populate_filespec(one, 0))
2672                        die("cannot read data blob for %s", one->path);
2673                prep_temp_blob(name, temp, one->data, one->size,
2674                               one->sha1, one->mode);
2675        }
2676        return temp;
2677}
2678
2679/* An external diff command takes:
2680 *
2681 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2682 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2683 *
2684 */
2685static void run_external_diff(const char *pgm,
2686                              const char *name,
2687                              const char *other,
2688                              struct diff_filespec *one,
2689                              struct diff_filespec *two,
2690                              const char *xfrm_msg,
2691                              int complete_rewrite)
2692{
2693        const char *spawn_arg[10];
2694        int retval;
2695        const char **arg = &spawn_arg[0];
2696
2697        if (one && two) {
2698                struct diff_tempfile *temp_one, *temp_two;
2699                const char *othername = (other ? other : name);
2700                temp_one = prepare_temp_file(name, one);
2701                temp_two = prepare_temp_file(othername, two);
2702                *arg++ = pgm;
2703                *arg++ = name;
2704                *arg++ = temp_one->name;
2705                *arg++ = temp_one->hex;
2706                *arg++ = temp_one->mode;
2707                *arg++ = temp_two->name;
2708                *arg++ = temp_two->hex;
2709                *arg++ = temp_two->mode;
2710                if (other) {
2711                        *arg++ = other;
2712                        *arg++ = xfrm_msg;
2713                }
2714        } else {
2715                *arg++ = pgm;
2716                *arg++ = name;
2717        }
2718        *arg = NULL;
2719        fflush(NULL);
2720        retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2721        remove_tempfile();
2722        if (retval) {
2723                fprintf(stderr, "external diff died, stopping at %s.\n", name);
2724                exit(1);
2725        }
2726}
2727
2728static int similarity_index(struct diff_filepair *p)
2729{
2730        return p->score * 100 / MAX_SCORE;
2731}
2732
2733static void fill_metainfo(struct strbuf *msg,
2734                          const char *name,
2735                          const char *other,
2736                          struct diff_filespec *one,
2737                          struct diff_filespec *two,
2738                          struct diff_options *o,
2739                          struct diff_filepair *p,
2740                          int *must_show_header,
2741                          int use_color)
2742{
2743        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2744        const char *reset = diff_get_color(use_color, DIFF_RESET);
2745        struct strbuf *msgbuf;
2746        char *line_prefix = "";
2747
2748        *must_show_header = 1;
2749        if (o->output_prefix) {
2750                msgbuf = o->output_prefix(o, o->output_prefix_data);
2751                line_prefix = msgbuf->buf;
2752        }
2753        strbuf_init(msg, PATH_MAX * 2 + 300);
2754        switch (p->status) {
2755        case DIFF_STATUS_COPIED:
2756                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2757                            line_prefix, set, similarity_index(p));
2758                strbuf_addf(msg, "%s\n%s%scopy from ",
2759                            reset,  line_prefix, set);
2760                quote_c_style(name, msg, NULL, 0);
2761                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2762                quote_c_style(other, msg, NULL, 0);
2763                strbuf_addf(msg, "%s\n", reset);
2764                break;
2765        case DIFF_STATUS_RENAMED:
2766                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2767                            line_prefix, set, similarity_index(p));
2768                strbuf_addf(msg, "%s\n%s%srename from ",
2769                            reset, line_prefix, set);
2770                quote_c_style(name, msg, NULL, 0);
2771                strbuf_addf(msg, "%s\n%s%srename to ",
2772                            reset, line_prefix, set);
2773                quote_c_style(other, msg, NULL, 0);
2774                strbuf_addf(msg, "%s\n", reset);
2775                break;
2776        case DIFF_STATUS_MODIFIED:
2777                if (p->score) {
2778                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2779                                    line_prefix,
2780                                    set, similarity_index(p), reset);
2781                        break;
2782                }
2783                /* fallthru */
2784        default:
2785                *must_show_header = 0;
2786        }
2787        if (one && two && hashcmp(one->sha1, two->sha1)) {
2788                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2789
2790                if (DIFF_OPT_TST(o, BINARY)) {
2791                        mmfile_t mf;
2792                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2793                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2794                                abbrev = 40;
2795                }
2796                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2797                            find_unique_abbrev(one->sha1, abbrev));
2798                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2799                if (one->mode == two->mode)
2800                        strbuf_addf(msg, " %06o", one->mode);
2801                strbuf_addf(msg, "%s\n", reset);
2802        }
2803}
2804
2805static void run_diff_cmd(const char *pgm,
2806                         const char *name,
2807                         const char *other,
2808                         const char *attr_path,
2809                         struct diff_filespec *one,
2810                         struct diff_filespec *two,
2811                         struct strbuf *msg,
2812                         struct diff_options *o,
2813                         struct diff_filepair *p)
2814{
2815        const char *xfrm_msg = NULL;
2816        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
2817        int must_show_header = 0;
2818
2819        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2820                pgm = NULL;
2821        else {
2822                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
2823                if (drv && drv->external)
2824                        pgm = drv->external;
2825        }
2826
2827        if (msg) {
2828                /*
2829                 * don't use colors when the header is intended for an
2830                 * external diff driver
2831                 */
2832                fill_metainfo(msg, name, other, one, two, o, p,
2833                              &must_show_header,
2834                              want_color(o->use_color) && !pgm);
2835                xfrm_msg = msg->len ? msg->buf : NULL;
2836        }
2837
2838        if (pgm) {
2839                run_external_diff(pgm, name, other, one, two, xfrm_msg,
2840                                  complete_rewrite);
2841                return;
2842        }
2843        if (one && two)
2844                builtin_diff(name, other ? other : name,
2845                             one, two, xfrm_msg, must_show_header,
2846                             o, complete_rewrite);
2847        else
2848                fprintf(o->file, "* Unmerged path %s\n", name);
2849}
2850
2851static void diff_fill_sha1_info(struct diff_filespec *one)
2852{
2853        if (DIFF_FILE_VALID(one)) {
2854                if (!one->sha1_valid) {
2855                        struct stat st;
2856                        if (!strcmp(one->path, "-")) {
2857                                hashcpy(one->sha1, null_sha1);
2858                                return;
2859                        }
2860                        if (lstat(one->path, &st) < 0)
2861                                die_errno("stat '%s'", one->path);
2862                        if (index_path(one->sha1, one->path, &st, 0))
2863                                die("cannot hash %s", one->path);
2864                }
2865        }
2866        else
2867                hashclr(one->sha1);
2868}
2869
2870static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2871{
2872        /* Strip the prefix but do not molest /dev/null and absolute paths */
2873        if (*namep && **namep != '/') {
2874                *namep += prefix_length;
2875                if (**namep == '/')
2876                        ++*namep;
2877        }
2878        if (*otherp && **otherp != '/') {
2879                *otherp += prefix_length;
2880                if (**otherp == '/')
2881                        ++*otherp;
2882        }
2883}
2884
2885static void run_diff(struct diff_filepair *p, struct diff_options *o)
2886{
2887        const char *pgm = external_diff();
2888        struct strbuf msg;
2889        struct diff_filespec *one = p->one;
2890        struct diff_filespec *two = p->two;
2891        const char *name;
2892        const char *other;
2893        const char *attr_path;
2894
2895        name  = p->one->path;
2896        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2897        attr_path = name;
2898        if (o->prefix_length)
2899                strip_prefix(o->prefix_length, &name, &other);
2900
2901        if (DIFF_PAIR_UNMERGED(p)) {
2902                run_diff_cmd(pgm, name, NULL, attr_path,
2903                             NULL, NULL, NULL, o, p);
2904                return;
2905        }
2906
2907        diff_fill_sha1_info(one);
2908        diff_fill_sha1_info(two);
2909
2910        if (!pgm &&
2911            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2912            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2913                /*
2914                 * a filepair that changes between file and symlink
2915                 * needs to be split into deletion and creation.
2916                 */
2917                struct diff_filespec *null = alloc_filespec(two->path);
2918                run_diff_cmd(NULL, name, other, attr_path,
2919                             one, null, &msg, o, p);
2920                free(null);
2921                strbuf_release(&msg);
2922
2923                null = alloc_filespec(one->path);
2924                run_diff_cmd(NULL, name, other, attr_path,
2925                             null, two, &msg, o, p);
2926                free(null);
2927        }
2928        else
2929                run_diff_cmd(pgm, name, other, attr_path,
2930                             one, two, &msg, o, p);
2931
2932        strbuf_release(&msg);
2933}
2934
2935static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2936                         struct diffstat_t *diffstat)
2937{
2938        const char *name;
2939        const char *other;
2940        int complete_rewrite = 0;
2941
2942        if (DIFF_PAIR_UNMERGED(p)) {
2943                /* unmerged */
2944                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2945                return;
2946        }
2947
2948        name = p->one->path;
2949        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2950
2951        if (o->prefix_length)
2952                strip_prefix(o->prefix_length, &name, &other);
2953
2954        diff_fill_sha1_info(p->one);
2955        diff_fill_sha1_info(p->two);
2956
2957        if (p->status == DIFF_STATUS_MODIFIED && p->score)
2958                complete_rewrite = 1;
2959        builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2960}
2961
2962static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2963{
2964        const char *name;
2965        const char *other;
2966        const char *attr_path;
2967
2968        if (DIFF_PAIR_UNMERGED(p)) {
2969                /* unmerged */
2970                return;
2971        }
2972
2973        name = p->one->path;
2974        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2975        attr_path = other ? other : name;
2976
2977        if (o->prefix_length)
2978                strip_prefix(o->prefix_length, &name, &other);
2979
2980        diff_fill_sha1_info(p->one);
2981        diff_fill_sha1_info(p->two);
2982
2983        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2984}
2985
2986void diff_setup(struct diff_options *options)
2987{
2988        memcpy(options, &default_diff_options, sizeof(*options));
2989
2990        options->file = stdout;
2991
2992        options->line_termination = '\n';
2993        options->break_opt = -1;
2994        options->rename_limit = -1;
2995        options->dirstat_permille = diff_dirstat_permille_default;
2996        options->context = 3;
2997
2998        options->change = diff_change;
2999        options->add_remove = diff_addremove;
3000        options->use_color = diff_use_color_default;
3001        options->detect_rename = diff_detect_rename_default;
3002
3003        if (diff_no_prefix) {
3004                options->a_prefix = options->b_prefix = "";
3005        } else if (!diff_mnemonic_prefix) {
3006                options->a_prefix = "a/";
3007                options->b_prefix = "b/";
3008        }
3009}
3010
3011int diff_setup_done(struct diff_options *options)
3012{
3013        int count = 0;
3014
3015        if (options->output_format & DIFF_FORMAT_NAME)
3016                count++;
3017        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3018                count++;
3019        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3020                count++;
3021        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3022                count++;
3023        if (count > 1)
3024                die("--name-only, --name-status, --check and -s are mutually exclusive");
3025
3026        /*
3027         * Most of the time we can say "there are changes"
3028         * only by checking if there are changed paths, but
3029         * --ignore-whitespace* options force us to look
3030         * inside contents.
3031         */
3032
3033        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3034            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3035            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3036                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3037        else
3038                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3039
3040        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3041                options->detect_rename = DIFF_DETECT_COPY;
3042
3043        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3044                options->prefix = NULL;
3045        if (options->prefix)
3046                options->prefix_length = strlen(options->prefix);
3047        else
3048                options->prefix_length = 0;
3049
3050        if (options->output_format & (DIFF_FORMAT_NAME |
3051                                      DIFF_FORMAT_NAME_STATUS |
3052                                      DIFF_FORMAT_CHECKDIFF |
3053                                      DIFF_FORMAT_NO_OUTPUT))
3054                options->output_format &= ~(DIFF_FORMAT_RAW |
3055                                            DIFF_FORMAT_NUMSTAT |
3056                                            DIFF_FORMAT_DIFFSTAT |
3057                                            DIFF_FORMAT_SHORTSTAT |
3058                                            DIFF_FORMAT_DIRSTAT |
3059                                            DIFF_FORMAT_SUMMARY |
3060                                            DIFF_FORMAT_PATCH);
3061
3062        /*
3063         * These cases always need recursive; we do not drop caller-supplied
3064         * recursive bits for other formats here.
3065         */
3066        if (options->output_format & (DIFF_FORMAT_PATCH |
3067                                      DIFF_FORMAT_NUMSTAT |
3068                                      DIFF_FORMAT_DIFFSTAT |
3069                                      DIFF_FORMAT_SHORTSTAT |
3070                                      DIFF_FORMAT_DIRSTAT |
3071                                      DIFF_FORMAT_SUMMARY |
3072                                      DIFF_FORMAT_CHECKDIFF))
3073                DIFF_OPT_SET(options, RECURSIVE);
3074        /*
3075         * Also pickaxe would not work very well if you do not say recursive
3076         */
3077        if (options->pickaxe)
3078                DIFF_OPT_SET(options, RECURSIVE);
3079        /*
3080         * When patches are generated, submodules diffed against the work tree
3081         * must be checked for dirtiness too so it can be shown in the output
3082         */
3083        if (options->output_format & DIFF_FORMAT_PATCH)
3084                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3085
3086        if (options->detect_rename && options->rename_limit < 0)
3087                options->rename_limit = diff_rename_limit_default;
3088        if (options->setup & DIFF_SETUP_USE_CACHE) {
3089                if (!active_cache)
3090                        /* read-cache does not die even when it fails
3091                         * so it is safe for us to do this here.  Also
3092                         * it does not smudge active_cache or active_nr
3093                         * when it fails, so we do not have to worry about
3094                         * cleaning it up ourselves either.
3095                         */
3096                        read_cache();
3097        }
3098        if (options->abbrev <= 0 || 40 < options->abbrev)
3099                options->abbrev = 40; /* full */
3100
3101        /*
3102         * It does not make sense to show the first hit we happened
3103         * to have found.  It does not make sense not to return with
3104         * exit code in such a case either.
3105         */
3106        if (DIFF_OPT_TST(options, QUICK)) {
3107                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3108                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3109        }
3110
3111        return 0;
3112}
3113
3114static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3115{
3116        char c, *eq;
3117        int len;
3118
3119        if (*arg != '-')
3120                return 0;
3121        c = *++arg;
3122        if (!c)
3123                return 0;
3124        if (c == arg_short) {
3125                c = *++arg;
3126                if (!c)
3127                        return 1;
3128                if (val && isdigit(c)) {
3129                        char *end;
3130                        int n = strtoul(arg, &end, 10);
3131                        if (*end)
3132                                return 0;
3133                        *val = n;
3134                        return 1;
3135                }
3136                return 0;
3137        }
3138        if (c != '-')
3139                return 0;
3140        arg++;
3141        eq = strchr(arg, '=');
3142        if (eq)
3143                len = eq - arg;
3144        else
3145                len = strlen(arg);
3146        if (!len || strncmp(arg, arg_long, len))
3147                return 0;
3148        if (eq) {
3149                int n;
3150                char *end;
3151                if (!isdigit(*++eq))
3152                        return 0;
3153                n = strtoul(eq, &end, 10);
3154                if (*end)
3155                        return 0;
3156                *val = n;
3157        }
3158        return 1;
3159}
3160
3161static int diff_scoreopt_parse(const char *opt);
3162
3163static inline int short_opt(char opt, const char **argv,
3164                            const char **optarg)
3165{
3166        const char *arg = argv[0];
3167        if (arg[0] != '-' || arg[1] != opt)
3168                return 0;
3169        if (arg[2] != '\0') {
3170                *optarg = arg + 2;
3171                return 1;
3172        }
3173        if (!argv[1])
3174                die("Option '%c' requires a value", opt);
3175        *optarg = argv[1];
3176        return 2;
3177}
3178
3179int parse_long_opt(const char *opt, const char **argv,
3180                   const char **optarg)
3181{
3182        const char *arg = argv[0];
3183        if (arg[0] != '-' || arg[1] != '-')
3184                return 0;
3185        arg += strlen("--");
3186        if (prefixcmp(arg, opt))
3187                return 0;
3188        arg += strlen(opt);
3189        if (*arg == '=') { /* sticked form: --option=value */
3190                *optarg = arg + 1;
3191                return 1;
3192        }
3193        if (*arg != '\0')
3194                return 0;
3195        /* separate form: --option value */
3196        if (!argv[1])
3197                die("Option '--%s' requires a value", opt);
3198        *optarg = argv[1];
3199        return 2;
3200}
3201
3202static int stat_opt(struct diff_options *options, const char **av)
3203{
3204        const char *arg = av[0];
3205        char *end;
3206        int width = options->stat_width;
3207        int name_width = options->stat_name_width;
3208        int argcount = 1;
3209
3210        arg += strlen("--stat");
3211        end = (char *)arg;
3212
3213        switch (*arg) {
3214        case '-':
3215                if (!prefixcmp(arg, "-width")) {
3216                        arg += strlen("-width");
3217                        if (*arg == '=')
3218                                width = strtoul(arg + 1, &end, 10);
3219                        else if (!*arg && !av[1])
3220                                die("Option '--stat-width' requires a value");
3221                        else if (!*arg) {
3222                                width = strtoul(av[1], &end, 10);
3223                                argcount = 2;
3224                        }
3225                } else if (!prefixcmp(arg, "-name-width")) {
3226                        arg += strlen("-name-width");
3227                        if (*arg == '=')
3228                                name_width = strtoul(arg + 1, &end, 10);
3229                        else if (!*arg && !av[1])
3230                                die("Option '--stat-name-width' requires a value");
3231                        else if (!*arg) {
3232                                name_width = strtoul(av[1], &end, 10);
3233                                argcount = 2;
3234                        }
3235                }
3236                break;
3237        case '=':
3238                width = strtoul(arg+1, &end, 10);
3239                if (*end == ',')
3240                        name_width = strtoul(end+1, &end, 10);
3241        }
3242
3243        /* Important! This checks all the error cases! */
3244        if (*end)
3245                return 0;
3246        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3247        options->stat_name_width = name_width;
3248        options->stat_width = width;
3249        return argcount;
3250}
3251
3252static int parse_dirstat_opt(struct diff_options *options, const char *params)
3253{
3254        struct strbuf errmsg = STRBUF_INIT;
3255        if (parse_dirstat_params(options, params, &errmsg))
3256                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3257                    errmsg.buf);
3258        strbuf_release(&errmsg);
3259        /*
3260         * The caller knows a dirstat-related option is given from the command
3261         * line; allow it to say "return this_function();"
3262         */
3263        options->output_format |= DIFF_FORMAT_DIRSTAT;
3264        return 1;
3265}
3266
3267int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3268{
3269        const char *arg = av[0];
3270        const char *optarg;
3271        int argcount;
3272
3273        /* Output format options */
3274        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3275                options->output_format |= DIFF_FORMAT_PATCH;
3276        else if (opt_arg(arg, 'U', "unified", &options->context))
3277                options->output_format |= DIFF_FORMAT_PATCH;
3278        else if (!strcmp(arg, "--raw"))
3279                options->output_format |= DIFF_FORMAT_RAW;
3280        else if (!strcmp(arg, "--patch-with-raw"))
3281                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3282        else if (!strcmp(arg, "--numstat"))
3283                options->output_format |= DIFF_FORMAT_NUMSTAT;
3284        else if (!strcmp(arg, "--shortstat"))
3285                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3286        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3287                return parse_dirstat_opt(options, "");
3288        else if (!prefixcmp(arg, "-X"))
3289                return parse_dirstat_opt(options, arg + 2);
3290        else if (!prefixcmp(arg, "--dirstat="))
3291                return parse_dirstat_opt(options, arg + 10);
3292        else if (!strcmp(arg, "--cumulative"))
3293                return parse_dirstat_opt(options, "cumulative");
3294        else if (!strcmp(arg, "--dirstat-by-file"))
3295                return parse_dirstat_opt(options, "files");
3296        else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3297                parse_dirstat_opt(options, "files");
3298                return parse_dirstat_opt(options, arg + 18);
3299        }
3300        else if (!strcmp(arg, "--check"))
3301                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3302        else if (!strcmp(arg, "--summary"))
3303                options->output_format |= DIFF_FORMAT_SUMMARY;
3304        else if (!strcmp(arg, "--patch-with-stat"))
3305                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3306        else if (!strcmp(arg, "--name-only"))
3307                options->output_format |= DIFF_FORMAT_NAME;
3308        else if (!strcmp(arg, "--name-status"))
3309                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3310        else if (!strcmp(arg, "-s"))
3311                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3312        else if (!prefixcmp(arg, "--stat"))
3313                /* --stat, --stat-width, or --stat-name-width */
3314                return stat_opt(options, av);
3315
3316        /* renames options */
3317        else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3318                 !strcmp(arg, "--break-rewrites")) {
3319                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3320                        return error("invalid argument to -B: %s", arg+2);
3321        }
3322        else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3323                 !strcmp(arg, "--find-renames")) {
3324                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3325                        return error("invalid argument to -M: %s", arg+2);
3326                options->detect_rename = DIFF_DETECT_RENAME;
3327        }
3328        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3329                options->irreversible_delete = 1;
3330        }
3331        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3332                 !strcmp(arg, "--find-copies")) {
3333                if (options->detect_rename == DIFF_DETECT_COPY)
3334                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3335                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3336                        return error("invalid argument to -C: %s", arg+2);
3337                options->detect_rename = DIFF_DETECT_COPY;
3338        }
3339        else if (!strcmp(arg, "--no-renames"))
3340                options->detect_rename = 0;
3341        else if (!strcmp(arg, "--relative"))
3342                DIFF_OPT_SET(options, RELATIVE_NAME);
3343        else if (!prefixcmp(arg, "--relative=")) {
3344                DIFF_OPT_SET(options, RELATIVE_NAME);
3345                options->prefix = arg + 11;
3346        }
3347
3348        /* xdiff options */
3349        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3350                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3351        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3352                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3353        else if (!strcmp(arg, "--ignore-space-at-eol"))
3354                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3355        else if (!strcmp(arg, "--patience"))
3356                DIFF_XDL_SET(options, PATIENCE_DIFF);
3357
3358        /* flags options */
3359        else if (!strcmp(arg, "--binary")) {
3360                options->output_format |= DIFF_FORMAT_PATCH;
3361                DIFF_OPT_SET(options, BINARY);
3362        }
3363        else if (!strcmp(arg, "--full-index"))
3364                DIFF_OPT_SET(options, FULL_INDEX);
3365        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3366                DIFF_OPT_SET(options, TEXT);
3367        else if (!strcmp(arg, "-R"))
3368                DIFF_OPT_SET(options, REVERSE_DIFF);
3369        else if (!strcmp(arg, "--find-copies-harder"))
3370                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3371        else if (!strcmp(arg, "--follow"))
3372                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3373        else if (!strcmp(arg, "--color"))
3374                options->use_color = 1;
3375        else if (!prefixcmp(arg, "--color=")) {
3376                int value = git_config_colorbool(NULL, arg+8);
3377                if (value < 0)
3378                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3379                options->use_color = value;
3380        }
3381        else if (!strcmp(arg, "--no-color"))
3382                options->use_color = 0;
3383        else if (!strcmp(arg, "--color-words")) {
3384                options->use_color = 1;
3385                options->word_diff = DIFF_WORDS_COLOR;
3386        }
3387        else if (!prefixcmp(arg, "--color-words=")) {
3388                options->use_color = 1;
3389                options->word_diff = DIFF_WORDS_COLOR;
3390                options->word_regex = arg + 14;
3391        }
3392        else if (!strcmp(arg, "--word-diff")) {
3393                if (options->word_diff == DIFF_WORDS_NONE)
3394                        options->word_diff = DIFF_WORDS_PLAIN;
3395        }
3396        else if (!prefixcmp(arg, "--word-diff=")) {
3397                const char *type = arg + 12;
3398                if (!strcmp(type, "plain"))
3399                        options->word_diff = DIFF_WORDS_PLAIN;
3400                else if (!strcmp(type, "color")) {
3401                        options->use_color = 1;
3402                        options->word_diff = DIFF_WORDS_COLOR;
3403                }
3404                else if (!strcmp(type, "porcelain"))
3405                        options->word_diff = DIFF_WORDS_PORCELAIN;
3406                else if (!strcmp(type, "none"))
3407                        options->word_diff = DIFF_WORDS_NONE;
3408                else
3409                        die("bad --word-diff argument: %s", type);
3410        }
3411        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3412                if (options->word_diff == DIFF_WORDS_NONE)
3413                        options->word_diff = DIFF_WORDS_PLAIN;
3414                options->word_regex = optarg;
3415                return argcount;
3416        }
3417        else if (!strcmp(arg, "--exit-code"))
3418                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3419        else if (!strcmp(arg, "--quiet"))
3420                DIFF_OPT_SET(options, QUICK);
3421        else if (!strcmp(arg, "--ext-diff"))
3422                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3423        else if (!strcmp(arg, "--no-ext-diff"))
3424                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3425        else if (!strcmp(arg, "--textconv"))
3426                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3427        else if (!strcmp(arg, "--no-textconv"))
3428                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3429        else if (!strcmp(arg, "--ignore-submodules")) {
3430                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3431                handle_ignore_submodules_arg(options, "all");
3432        } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3433                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3434                handle_ignore_submodules_arg(options, arg + 20);
3435        } else if (!strcmp(arg, "--submodule"))
3436                DIFF_OPT_SET(options, SUBMODULE_LOG);
3437        else if (!prefixcmp(arg, "--submodule=")) {
3438                if (!strcmp(arg + 12, "log"))
3439                        DIFF_OPT_SET(options, SUBMODULE_LOG);
3440        }
3441
3442        /* misc options */
3443        else if (!strcmp(arg, "-z"))
3444                options->line_termination = 0;
3445        else if ((argcount = short_opt('l', av, &optarg))) {
3446                options->rename_limit = strtoul(optarg, NULL, 10);
3447                return argcount;
3448        }
3449        else if ((argcount = short_opt('S', av, &optarg))) {
3450                options->pickaxe = optarg;
3451                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3452                return argcount;
3453        } else if ((argcount = short_opt('G', av, &optarg))) {
3454                options->pickaxe = optarg;
3455                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3456                return argcount;
3457        }
3458        else if (!strcmp(arg, "--pickaxe-all"))
3459                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3460        else if (!strcmp(arg, "--pickaxe-regex"))
3461                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3462        else if ((argcount = short_opt('O', av, &optarg))) {
3463                options->orderfile = optarg;
3464                return argcount;
3465        }
3466        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3467                options->filter = optarg;
3468                return argcount;
3469        }
3470        else if (!strcmp(arg, "--abbrev"))
3471                options->abbrev = DEFAULT_ABBREV;
3472        else if (!prefixcmp(arg, "--abbrev=")) {
3473                options->abbrev = strtoul(arg + 9, NULL, 10);
3474                if (options->abbrev < MINIMUM_ABBREV)
3475                        options->abbrev = MINIMUM_ABBREV;
3476                else if (40 < options->abbrev)
3477                        options->abbrev = 40;
3478        }
3479        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3480                options->a_prefix = optarg;
3481                return argcount;
3482        }
3483        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3484                options->b_prefix = optarg;
3485                return argcount;
3486        }
3487        else if (!strcmp(arg, "--no-prefix"))
3488                options->a_prefix = options->b_prefix = "";
3489        else if (opt_arg(arg, '\0', "inter-hunk-context",
3490                         &options->interhunkcontext))
3491                ;
3492        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3493                options->file = fopen(optarg, "w");
3494                if (!options->file)
3495                        die_errno("Could not open '%s'", optarg);
3496                options->close_file = 1;
3497                return argcount;
3498        } else
3499                return 0;
3500        return 1;
3501}
3502
3503int parse_rename_score(const char **cp_p)
3504{
3505        unsigned long num, scale;
3506        int ch, dot;
3507        const char *cp = *cp_p;
3508
3509        num = 0;
3510        scale = 1;
3511        dot = 0;
3512        for (;;) {
3513                ch = *cp;
3514                if ( !dot && ch == '.' ) {
3515                        scale = 1;
3516                        dot = 1;
3517                } else if ( ch == '%' ) {
3518                        scale = dot ? scale*100 : 100;
3519                        cp++;   /* % is always at the end */
3520                        break;
3521                } else if ( ch >= '0' && ch <= '9' ) {
3522                        if ( scale < 100000 ) {
3523                                scale *= 10;
3524                                num = (num*10) + (ch-'0');
3525                        }
3526                } else {
3527                        break;
3528                }
3529                cp++;
3530        }
3531        *cp_p = cp;
3532
3533        /* user says num divided by scale and we say internally that
3534         * is MAX_SCORE * num / scale.
3535         */
3536        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3537}
3538
3539static int diff_scoreopt_parse(const char *opt)
3540{
3541        int opt1, opt2, cmd;
3542
3543        if (*opt++ != '-')
3544                return -1;
3545        cmd = *opt++;
3546        if (cmd == '-') {
3547                /* convert the long-form arguments into short-form versions */
3548                if (!prefixcmp(opt, "break-rewrites")) {
3549                        opt += strlen("break-rewrites");
3550                        if (*opt == 0 || *opt++ == '=')
3551                                cmd = 'B';
3552                } else if (!prefixcmp(opt, "find-copies")) {
3553                        opt += strlen("find-copies");
3554                        if (*opt == 0 || *opt++ == '=')
3555                                cmd = 'C';
3556                } else if (!prefixcmp(opt, "find-renames")) {
3557                        opt += strlen("find-renames");
3558                        if (*opt == 0 || *opt++ == '=')
3559                                cmd = 'M';
3560                }
3561        }
3562        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3563                return -1; /* that is not a -M, -C nor -B option */
3564
3565        opt1 = parse_rename_score(&opt);
3566        if (cmd != 'B')
3567                opt2 = 0;
3568        else {
3569                if (*opt == 0)
3570                        opt2 = 0;
3571                else if (*opt != '/')
3572                        return -1; /* we expect -B80/99 or -B80 */
3573                else {
3574                        opt++;
3575                        opt2 = parse_rename_score(&opt);
3576                }
3577        }
3578        if (*opt != 0)
3579                return -1;
3580        return opt1 | (opt2 << 16);
3581}
3582
3583struct diff_queue_struct diff_queued_diff;
3584
3585void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3586{
3587        if (queue->alloc <= queue->nr) {
3588                queue->alloc = alloc_nr(queue->alloc);
3589                queue->queue = xrealloc(queue->queue,
3590                                        sizeof(dp) * queue->alloc);
3591        }
3592        queue->queue[queue->nr++] = dp;
3593}
3594
3595struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3596                                 struct diff_filespec *one,
3597                                 struct diff_filespec *two)
3598{
3599        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3600        dp->one = one;
3601        dp->two = two;
3602        if (queue)
3603                diff_q(queue, dp);
3604        return dp;
3605}
3606
3607void diff_free_filepair(struct diff_filepair *p)
3608{
3609        free_filespec(p->one);
3610        free_filespec(p->two);
3611        free(p);
3612}
3613
3614/* This is different from find_unique_abbrev() in that
3615 * it stuffs the result with dots for alignment.
3616 */
3617const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3618{
3619        int abblen;
3620        const char *abbrev;
3621        if (len == 40)
3622                return sha1_to_hex(sha1);
3623
3624        abbrev = find_unique_abbrev(sha1, len);
3625        abblen = strlen(abbrev);
3626        if (abblen < 37) {
3627                static char hex[41];
3628                if (len < abblen && abblen <= len + 2)
3629                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3630                else
3631                        sprintf(hex, "%s...", abbrev);
3632                return hex;
3633        }
3634        return sha1_to_hex(sha1);
3635}
3636
3637static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3638{
3639        int line_termination = opt->line_termination;
3640        int inter_name_termination = line_termination ? '\t' : '\0';
3641        if (opt->output_prefix) {
3642                struct strbuf *msg = NULL;
3643                msg = opt->output_prefix(opt, opt->output_prefix_data);
3644                fprintf(opt->file, "%s", msg->buf);
3645        }
3646
3647        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3648                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3649                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
3650                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3651        }
3652        if (p->score) {
3653                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3654                        inter_name_termination);
3655        } else {
3656                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3657        }
3658
3659        if (p->status == DIFF_STATUS_COPIED ||
3660            p->status == DIFF_STATUS_RENAMED) {
3661                const char *name_a, *name_b;
3662                name_a = p->one->path;
3663                name_b = p->two->path;
3664                strip_prefix(opt->prefix_length, &name_a, &name_b);
3665                write_name_quoted(name_a, opt->file, inter_name_termination);
3666                write_name_quoted(name_b, opt->file, line_termination);
3667        } else {
3668                const char *name_a, *name_b;
3669                name_a = p->one->mode ? p->one->path : p->two->path;
3670                name_b = NULL;
3671                strip_prefix(opt->prefix_length, &name_a, &name_b);
3672                write_name_quoted(name_a, opt->file, line_termination);
3673        }
3674}
3675
3676int diff_unmodified_pair(struct diff_filepair *p)
3677{
3678        /* This function is written stricter than necessary to support
3679         * the currently implemented transformers, but the idea is to
3680         * let transformers to produce diff_filepairs any way they want,
3681         * and filter and clean them up here before producing the output.
3682         */
3683        struct diff_filespec *one = p->one, *two = p->two;
3684
3685        if (DIFF_PAIR_UNMERGED(p))
3686                return 0; /* unmerged is interesting */
3687
3688        /* deletion, addition, mode or type change
3689         * and rename are all interesting.
3690         */
3691        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3692            DIFF_PAIR_MODE_CHANGED(p) ||
3693            strcmp(one->path, two->path))
3694                return 0;
3695
3696        /* both are valid and point at the same path.  that is, we are
3697         * dealing with a change.
3698         */
3699        if (one->sha1_valid && two->sha1_valid &&
3700            !hashcmp(one->sha1, two->sha1) &&
3701            !one->dirty_submodule && !two->dirty_submodule)
3702                return 1; /* no change */
3703        if (!one->sha1_valid && !two->sha1_valid)
3704                return 1; /* both look at the same file on the filesystem. */
3705        return 0;
3706}
3707
3708static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3709{
3710        if (diff_unmodified_pair(p))
3711                return;
3712
3713        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3714            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3715                return; /* no tree diffs in patch format */
3716
3717        run_diff(p, o);
3718}
3719
3720static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3721                            struct diffstat_t *diffstat)
3722{
3723        if (diff_unmodified_pair(p))
3724                return;
3725
3726        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3727            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3728                return; /* no useful stat for tree diffs */
3729
3730        run_diffstat(p, o, diffstat);
3731}
3732
3733static void diff_flush_checkdiff(struct diff_filepair *p,
3734                struct diff_options *o)
3735{
3736        if (diff_unmodified_pair(p))
3737                return;
3738
3739        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3740            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3741                return; /* nothing to check in tree diffs */
3742
3743        run_checkdiff(p, o);
3744}
3745
3746int diff_queue_is_empty(void)
3747{
3748        struct diff_queue_struct *q = &diff_queued_diff;
3749        int i;
3750        for (i = 0; i < q->nr; i++)
3751                if (!diff_unmodified_pair(q->queue[i]))
3752                        return 0;
3753        return 1;
3754}
3755
3756#if DIFF_DEBUG
3757void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
3758{
3759        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
3760                x, one ? one : "",
3761                s->path,
3762                DIFF_FILE_VALID(s) ? "valid" : "invalid",
3763                s->mode,
3764                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
3765        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
3766                x, one ? one : "",
3767                s->size, s->xfrm_flags);
3768}
3769
3770void diff_debug_filepair(const struct diff_filepair *p, int i)
3771{
3772        diff_debug_filespec(p->one, i, "one");
3773        diff_debug_filespec(p->two, i, "two");
3774        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
3775                p->score, p->status ? p->status : '?',
3776                p->one->rename_used, p->broken_pair);
3777}
3778
3779void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
3780{
3781        int i;
3782        if (msg)
3783                fprintf(stderr, "%s\n", msg);
3784        fprintf(stderr, "q->nr = %d\n", q->nr);
3785        for (i = 0; i < q->nr; i++) {
3786                struct diff_filepair *p = q->queue[i];
3787                diff_debug_filepair(p, i);
3788        }
3789}
3790#endif
3791
3792static void diff_resolve_rename_copy(void)
3793{
3794        int i;
3795        struct diff_filepair *p;
3796        struct diff_queue_struct *q = &diff_queued_diff;
3797
3798        diff_debug_queue("resolve-rename-copy", q);
3799
3800        for (i = 0; i < q->nr; i++) {
3801                p = q->queue[i];
3802                p->status = 0; /* undecided */
3803                if (DIFF_PAIR_UNMERGED(p))
3804                        p->status = DIFF_STATUS_UNMERGED;
3805                else if (!DIFF_FILE_VALID(p->one))
3806                        p->status = DIFF_STATUS_ADDED;
3807                else if (!DIFF_FILE_VALID(p->two))
3808                        p->status = DIFF_STATUS_DELETED;
3809                else if (DIFF_PAIR_TYPE_CHANGED(p))
3810                        p->status = DIFF_STATUS_TYPE_CHANGED;
3811
3812                /* from this point on, we are dealing with a pair
3813                 * whose both sides are valid and of the same type, i.e.
3814                 * either in-place edit or rename/copy edit.
3815                 */
3816                else if (DIFF_PAIR_RENAME(p)) {
3817                        /*
3818                         * A rename might have re-connected a broken
3819                         * pair up, causing the pathnames to be the
3820                         * same again. If so, that's not a rename at
3821                         * all, just a modification..
3822                         *
3823                         * Otherwise, see if this source was used for
3824                         * multiple renames, in which case we decrement
3825                         * the count, and call it a copy.
3826                         */
3827                        if (!strcmp(p->one->path, p->two->path))
3828                                p->status = DIFF_STATUS_MODIFIED;
3829                        else if (--p->one->rename_used > 0)
3830                                p->status = DIFF_STATUS_COPIED;
3831                        else
3832                                p->status = DIFF_STATUS_RENAMED;
3833                }
3834                else if (hashcmp(p->one->sha1, p->two->sha1) ||
3835                         p->one->mode != p->two->mode ||
3836                         p->one->dirty_submodule ||
3837                         p->two->dirty_submodule ||
3838                         is_null_sha1(p->one->sha1))
3839                        p->status = DIFF_STATUS_MODIFIED;
3840                else {
3841                        /* This is a "no-change" entry and should not
3842                         * happen anymore, but prepare for broken callers.
3843                         */
3844                        error("feeding unmodified %s to diffcore",
3845                              p->one->path);
3846                        p->status = DIFF_STATUS_UNKNOWN;
3847                }
3848        }
3849        diff_debug_queue("resolve-rename-copy done", q);
3850}
3851
3852static int check_pair_status(struct diff_filepair *p)
3853{
3854        switch (p->status) {
3855        case DIFF_STATUS_UNKNOWN:
3856                return 0;
3857        case 0:
3858                die("internal error in diff-resolve-rename-copy");
3859        default:
3860                return 1;
3861        }
3862}
3863
3864static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
3865{
3866        int fmt = opt->output_format;
3867
3868        if (fmt & DIFF_FORMAT_CHECKDIFF)
3869                diff_flush_checkdiff(p, opt);
3870        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
3871                diff_flush_raw(p, opt);
3872        else if (fmt & DIFF_FORMAT_NAME) {
3873                const char *name_a, *name_b;
3874                name_a = p->two->path;
3875                name_b = NULL;
3876                strip_prefix(opt->prefix_length, &name_a, &name_b);
3877                write_name_quoted(name_a, opt->file, opt->line_termination);
3878        }
3879}
3880
3881static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
3882{
3883        if (fs->mode)
3884                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
3885        else
3886                fprintf(file, " %s ", newdelete);
3887        write_name_quoted(fs->path, file, '\n');
3888}
3889
3890
3891static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
3892                const char *line_prefix)
3893{
3894        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
3895                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
3896                        p->two->mode, show_name ? ' ' : '\n');
3897                if (show_name) {
3898                        write_name_quoted(p->two->path, file, '\n');
3899                }
3900        }
3901}
3902
3903static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
3904                        const char *line_prefix)
3905{
3906        char *names = pprint_rename(p->one->path, p->two->path);
3907
3908        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3909        free(names);
3910        show_mode_change(file, p, 0, line_prefix);
3911}
3912
3913static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
3914{
3915        FILE *file = opt->file;
3916        char *line_prefix = "";
3917
3918        if (opt->output_prefix) {
3919                struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
3920                line_prefix = buf->buf;
3921        }
3922
3923        switch(p->status) {
3924        case DIFF_STATUS_DELETED:
3925                fputs(line_prefix, file);
3926                show_file_mode_name(file, "delete", p->one);
3927                break;
3928        case DIFF_STATUS_ADDED:
3929                fputs(line_prefix, file);
3930                show_file_mode_name(file, "create", p->two);
3931                break;
3932        case DIFF_STATUS_COPIED:
3933                fputs(line_prefix, file);
3934                show_rename_copy(file, "copy", p, line_prefix);
3935                break;
3936        case DIFF_STATUS_RENAMED:
3937                fputs(line_prefix, file);
3938                show_rename_copy(file, "rename", p, line_prefix);
3939                break;
3940        default:
3941                if (p->score) {
3942                        fprintf(file, "%s rewrite ", line_prefix);
3943                        write_name_quoted(p->two->path, file, ' ');
3944                        fprintf(file, "(%d%%)\n", similarity_index(p));
3945                }
3946                show_mode_change(file, p, !p->score, line_prefix);
3947                break;
3948        }
3949}
3950
3951struct patch_id_t {
3952        git_SHA_CTX *ctx;
3953        int patchlen;
3954};
3955
3956static int remove_space(char *line, int len)
3957{
3958        int i;
3959        char *dst = line;
3960        unsigned char c;
3961
3962        for (i = 0; i < len; i++)
3963                if (!isspace((c = line[i])))
3964                        *dst++ = c;
3965
3966        return dst - line;
3967}
3968
3969static void patch_id_consume(void *priv, char *line, unsigned long len)
3970{
3971        struct patch_id_t *data = priv;
3972        int new_len;
3973
3974        /* Ignore line numbers when computing the SHA1 of the patch */
3975        if (!prefixcmp(line, "@@ -"))
3976                return;
3977
3978        new_len = remove_space(line, len);
3979
3980        git_SHA1_Update(data->ctx, line, new_len);
3981        data->patchlen += new_len;
3982}
3983
3984/* returns 0 upon success, and writes result into sha1 */
3985static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
3986{
3987        struct diff_queue_struct *q = &diff_queued_diff;
3988        int i;
3989        git_SHA_CTX ctx;
3990        struct patch_id_t data;
3991        char buffer[PATH_MAX * 4 + 20];
3992
3993        git_SHA1_Init(&ctx);
3994        memset(&data, 0, sizeof(struct patch_id_t));
3995        data.ctx = &ctx;
3996
3997        for (i = 0; i < q->nr; i++) {
3998                xpparam_t xpp;
3999                xdemitconf_t xecfg;
4000                mmfile_t mf1, mf2;
4001                struct diff_filepair *p = q->queue[i];
4002                int len1, len2;
4003
4004                memset(&xpp, 0, sizeof(xpp));
4005                memset(&xecfg, 0, sizeof(xecfg));
4006                if (p->status == 0)
4007                        return error("internal diff status error");
4008                if (p->status == DIFF_STATUS_UNKNOWN)
4009                        continue;
4010                if (diff_unmodified_pair(p))
4011                        continue;
4012                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4013                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4014                        continue;
4015                if (DIFF_PAIR_UNMERGED(p))
4016                        continue;
4017
4018                diff_fill_sha1_info(p->one);
4019                diff_fill_sha1_info(p->two);
4020                if (fill_mmfile(&mf1, p->one) < 0 ||
4021                                fill_mmfile(&mf2, p->two) < 0)
4022                        return error("unable to read files to diff");
4023
4024                len1 = remove_space(p->one->path, strlen(p->one->path));
4025                len2 = remove_space(p->two->path, strlen(p->two->path));
4026                if (p->one->mode == 0)
4027                        len1 = snprintf(buffer, sizeof(buffer),
4028                                        "diff--gita/%.*sb/%.*s"
4029                                        "newfilemode%06o"
4030                                        "---/dev/null"
4031                                        "+++b/%.*s",
4032                                        len1, p->one->path,
4033                                        len2, p->two->path,
4034                                        p->two->mode,
4035                                        len2, p->two->path);
4036                else if (p->two->mode == 0)
4037                        len1 = snprintf(buffer, sizeof(buffer),
4038                                        "diff--gita/%.*sb/%.*s"
4039                                        "deletedfilemode%06o"
4040                                        "---a/%.*s"
4041                                        "+++/dev/null",
4042                                        len1, p->one->path,
4043                                        len2, p->two->path,
4044                                        p->one->mode,
4045                                        len1, p->one->path);
4046                else
4047                        len1 = snprintf(buffer, sizeof(buffer),
4048                                        "diff--gita/%.*sb/%.*s"
4049                                        "---a/%.*s"
4050                                        "+++b/%.*s",
4051                                        len1, p->one->path,
4052                                        len2, p->two->path,
4053                                        len1, p->one->path,
4054                                        len2, p->two->path);
4055                git_SHA1_Update(&ctx, buffer, len1);
4056
4057                if (diff_filespec_is_binary(p->one) ||
4058                    diff_filespec_is_binary(p->two)) {
4059                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4060                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4061                        continue;
4062                }
4063
4064                xpp.flags = 0;
4065                xecfg.ctxlen = 3;
4066                xecfg.flags = 0;
4067                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4068                              &xpp, &xecfg);
4069        }
4070
4071        git_SHA1_Final(sha1, &ctx);
4072        return 0;
4073}
4074
4075int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4076{
4077        struct diff_queue_struct *q = &diff_queued_diff;
4078        int i;
4079        int result = diff_get_patch_id(options, sha1);
4080
4081        for (i = 0; i < q->nr; i++)
4082                diff_free_filepair(q->queue[i]);
4083
4084        free(q->queue);
4085        DIFF_QUEUE_CLEAR(q);
4086
4087        return result;
4088}
4089
4090static int is_summary_empty(const struct diff_queue_struct *q)
4091{
4092        int i;
4093
4094        for (i = 0; i < q->nr; i++) {
4095                const struct diff_filepair *p = q->queue[i];
4096
4097                switch (p->status) {
4098                case DIFF_STATUS_DELETED:
4099                case DIFF_STATUS_ADDED:
4100                case DIFF_STATUS_COPIED:
4101                case DIFF_STATUS_RENAMED:
4102                        return 0;
4103                default:
4104                        if (p->score)
4105                                return 0;
4106                        if (p->one->mode && p->two->mode &&
4107                            p->one->mode != p->two->mode)
4108                                return 0;
4109                        break;
4110                }
4111        }
4112        return 1;
4113}
4114
4115static const char rename_limit_warning[] =
4116"inexact rename detection was skipped due to too many files.";
4117
4118static const char degrade_cc_to_c_warning[] =
4119"only found copies from modified paths due to too many files.";
4120
4121static const char rename_limit_advice[] =
4122"you may want to set your %s variable to at least "
4123"%d and retry the command.";
4124
4125void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4126{
4127        if (degraded_cc)
4128                warning(degrade_cc_to_c_warning);
4129        else if (needed)
4130                warning(rename_limit_warning);
4131        else
4132                return;
4133        if (0 < needed && needed < 32767)
4134                warning(rename_limit_advice, varname, needed);
4135}
4136
4137void diff_flush(struct diff_options *options)
4138{
4139        struct diff_queue_struct *q = &diff_queued_diff;
4140        int i, output_format = options->output_format;
4141        int separator = 0;
4142        int dirstat_by_line = 0;
4143
4144        /*
4145         * Order: raw, stat, summary, patch
4146         * or:    name/name-status/checkdiff (other bits clear)
4147         */
4148        if (!q->nr)
4149                goto free_queue;
4150
4151        if (output_format & (DIFF_FORMAT_RAW |
4152                             DIFF_FORMAT_NAME |
4153                             DIFF_FORMAT_NAME_STATUS |
4154                             DIFF_FORMAT_CHECKDIFF)) {
4155                for (i = 0; i < q->nr; i++) {
4156                        struct diff_filepair *p = q->queue[i];
4157                        if (check_pair_status(p))
4158                                flush_one_pair(p, options);
4159                }
4160                separator++;
4161        }
4162
4163        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4164                dirstat_by_line = 1;
4165
4166        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4167            dirstat_by_line) {
4168                struct diffstat_t diffstat;
4169
4170                memset(&diffstat, 0, sizeof(struct diffstat_t));
4171                for (i = 0; i < q->nr; i++) {
4172                        struct diff_filepair *p = q->queue[i];
4173                        if (check_pair_status(p))
4174                                diff_flush_stat(p, options, &diffstat);
4175                }
4176                if (output_format & DIFF_FORMAT_NUMSTAT)
4177                        show_numstat(&diffstat, options);
4178                if (output_format & DIFF_FORMAT_DIFFSTAT)
4179                        show_stats(&diffstat, options);
4180                if (output_format & DIFF_FORMAT_SHORTSTAT)
4181                        show_shortstats(&diffstat, options);
4182                if (output_format & DIFF_FORMAT_DIRSTAT)
4183                        show_dirstat_by_line(&diffstat, options);
4184                free_diffstat_info(&diffstat);
4185                separator++;
4186        }
4187        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4188                show_dirstat(options);
4189
4190        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4191                for (i = 0; i < q->nr; i++) {
4192                        diff_summary(options, q->queue[i]);
4193                }
4194                separator++;
4195        }
4196
4197        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4198            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4199            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4200                /*
4201                 * run diff_flush_patch for the exit status. setting
4202                 * options->file to /dev/null should be safe, becaue we
4203                 * aren't supposed to produce any output anyway.
4204                 */
4205                if (options->close_file)
4206                        fclose(options->file);
4207                options->file = fopen("/dev/null", "w");
4208                if (!options->file)
4209                        die_errno("Could not open /dev/null");
4210                options->close_file = 1;
4211                for (i = 0; i < q->nr; i++) {
4212                        struct diff_filepair *p = q->queue[i];
4213                        if (check_pair_status(p))
4214                                diff_flush_patch(p, options);
4215                        if (options->found_changes)
4216                                break;
4217                }
4218        }
4219
4220        if (output_format & DIFF_FORMAT_PATCH) {
4221                if (separator) {
4222                        putc(options->line_termination, options->file);
4223                        if (options->stat_sep) {
4224                                /* attach patch instead of inline */
4225                                fputs(options->stat_sep, options->file);
4226                        }
4227                }
4228
4229                for (i = 0; i < q->nr; i++) {
4230                        struct diff_filepair *p = q->queue[i];
4231                        if (check_pair_status(p))
4232                                diff_flush_patch(p, options);
4233                }
4234        }
4235
4236        if (output_format & DIFF_FORMAT_CALLBACK)
4237                options->format_callback(q, options, options->format_callback_data);
4238
4239        for (i = 0; i < q->nr; i++)
4240                diff_free_filepair(q->queue[i]);
4241free_queue:
4242        free(q->queue);
4243        DIFF_QUEUE_CLEAR(q);
4244        if (options->close_file)
4245                fclose(options->file);
4246
4247        /*
4248         * Report the content-level differences with HAS_CHANGES;
4249         * diff_addremove/diff_change does not set the bit when
4250         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4251         */
4252        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4253                if (options->found_changes)
4254                        DIFF_OPT_SET(options, HAS_CHANGES);
4255                else
4256                        DIFF_OPT_CLR(options, HAS_CHANGES);
4257        }
4258}
4259
4260static void diffcore_apply_filter(const char *filter)
4261{
4262        int i;
4263        struct diff_queue_struct *q = &diff_queued_diff;
4264        struct diff_queue_struct outq;
4265        DIFF_QUEUE_CLEAR(&outq);
4266
4267        if (!filter)
4268                return;
4269
4270        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4271                int found;
4272                for (i = found = 0; !found && i < q->nr; i++) {
4273                        struct diff_filepair *p = q->queue[i];
4274                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4275                             ((p->score &&
4276                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4277                              (!p->score &&
4278                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4279                            ((p->status != DIFF_STATUS_MODIFIED) &&
4280                             strchr(filter, p->status)))
4281                                found++;
4282                }
4283                if (found)
4284                        return;
4285
4286                /* otherwise we will clear the whole queue
4287                 * by copying the empty outq at the end of this
4288                 * function, but first clear the current entries
4289                 * in the queue.
4290                 */
4291                for (i = 0; i < q->nr; i++)
4292                        diff_free_filepair(q->queue[i]);
4293        }
4294        else {
4295                /* Only the matching ones */
4296                for (i = 0; i < q->nr; i++) {
4297                        struct diff_filepair *p = q->queue[i];
4298
4299                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4300                             ((p->score &&
4301                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4302                              (!p->score &&
4303                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4304                            ((p->status != DIFF_STATUS_MODIFIED) &&
4305                             strchr(filter, p->status)))
4306                                diff_q(&outq, p);
4307                        else
4308                                diff_free_filepair(p);
4309                }
4310        }
4311        free(q->queue);
4312        *q = outq;
4313}
4314
4315/* Check whether two filespecs with the same mode and size are identical */
4316static int diff_filespec_is_identical(struct diff_filespec *one,
4317                                      struct diff_filespec *two)
4318{
4319        if (S_ISGITLINK(one->mode))
4320                return 0;
4321        if (diff_populate_filespec(one, 0))
4322                return 0;
4323        if (diff_populate_filespec(two, 0))
4324                return 0;
4325        return !memcmp(one->data, two->data, one->size);
4326}
4327
4328static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4329{
4330        int i;
4331        struct diff_queue_struct *q = &diff_queued_diff;
4332        struct diff_queue_struct outq;
4333        DIFF_QUEUE_CLEAR(&outq);
4334
4335        for (i = 0; i < q->nr; i++) {
4336                struct diff_filepair *p = q->queue[i];
4337
4338                /*
4339                 * 1. Entries that come from stat info dirtiness
4340                 *    always have both sides (iow, not create/delete),
4341                 *    one side of the object name is unknown, with
4342                 *    the same mode and size.  Keep the ones that
4343                 *    do not match these criteria.  They have real
4344                 *    differences.
4345                 *
4346                 * 2. At this point, the file is known to be modified,
4347                 *    with the same mode and size, and the object
4348                 *    name of one side is unknown.  Need to inspect
4349                 *    the identical contents.
4350                 */
4351                if (!DIFF_FILE_VALID(p->one) || /* (1) */
4352                    !DIFF_FILE_VALID(p->two) ||
4353                    (p->one->sha1_valid && p->two->sha1_valid) ||
4354                    (p->one->mode != p->two->mode) ||
4355                    diff_populate_filespec(p->one, 1) ||
4356                    diff_populate_filespec(p->two, 1) ||
4357                    (p->one->size != p->two->size) ||
4358                    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4359                        diff_q(&outq, p);
4360                else {
4361                        /*
4362                         * The caller can subtract 1 from skip_stat_unmatch
4363                         * to determine how many paths were dirty only
4364                         * due to stat info mismatch.
4365                         */
4366                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4367                                diffopt->skip_stat_unmatch++;
4368                        diff_free_filepair(p);
4369                }
4370        }
4371        free(q->queue);
4372        *q = outq;
4373}
4374
4375static int diffnamecmp(const void *a_, const void *b_)
4376{
4377        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4378        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4379        const char *name_a, *name_b;
4380
4381        name_a = a->one ? a->one->path : a->two->path;
4382        name_b = b->one ? b->one->path : b->two->path;
4383        return strcmp(name_a, name_b);
4384}
4385
4386void diffcore_fix_diff_index(struct diff_options *options)
4387{
4388        struct diff_queue_struct *q = &diff_queued_diff;
4389        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4390}
4391
4392void diffcore_std(struct diff_options *options)
4393{
4394        if (options->skip_stat_unmatch)
4395                diffcore_skip_stat_unmatch(options);
4396        if (!options->found_follow) {
4397                /* See try_to_follow_renames() in tree-diff.c */
4398                if (options->break_opt != -1)
4399                        diffcore_break(options->break_opt);
4400                if (options->detect_rename)
4401                        diffcore_rename(options);
4402                if (options->break_opt != -1)
4403                        diffcore_merge_broken();
4404        }
4405        if (options->pickaxe)
4406                diffcore_pickaxe(options);
4407        if (options->orderfile)
4408                diffcore_order(options->orderfile);
4409        if (!options->found_follow)
4410                /* See try_to_follow_renames() in tree-diff.c */
4411                diff_resolve_rename_copy();
4412        diffcore_apply_filter(options->filter);
4413
4414        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4415                DIFF_OPT_SET(options, HAS_CHANGES);
4416        else
4417                DIFF_OPT_CLR(options, HAS_CHANGES);
4418
4419        options->found_follow = 0;
4420}
4421
4422int diff_result_code(struct diff_options *opt, int status)
4423{
4424        int result = 0;
4425
4426        diff_warn_rename_limit("diff.renamelimit",
4427                               opt->needed_rename_limit,
4428                               opt->degraded_cc_to_c);
4429        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4430            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4431                return status;
4432        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4433            DIFF_OPT_TST(opt, HAS_CHANGES))
4434                result |= 01;
4435        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4436            DIFF_OPT_TST(opt, CHECK_FAILED))
4437                result |= 02;
4438        return result;
4439}
4440
4441int diff_can_quit_early(struct diff_options *opt)
4442{
4443        return (DIFF_OPT_TST(opt, QUICK) &&
4444                !opt->filter &&
4445                DIFF_OPT_TST(opt, HAS_CHANGES));
4446}
4447
4448/*
4449 * Shall changes to this submodule be ignored?
4450 *
4451 * Submodule changes can be configured to be ignored separately for each path,
4452 * but that configuration can be overridden from the command line.
4453 */
4454static int is_submodule_ignored(const char *path, struct diff_options *options)
4455{
4456        int ignored = 0;
4457        unsigned orig_flags = options->flags;
4458        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4459                set_diffopt_flags_from_submodule_config(options, path);
4460        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4461                ignored = 1;
4462        options->flags = orig_flags;
4463        return ignored;
4464}
4465
4466void diff_addremove(struct diff_options *options,
4467                    int addremove, unsigned mode,
4468                    const unsigned char *sha1,
4469                    const char *concatpath, unsigned dirty_submodule)
4470{
4471        struct diff_filespec *one, *two;
4472
4473        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4474                return;
4475
4476        /* This may look odd, but it is a preparation for
4477         * feeding "there are unchanged files which should
4478         * not produce diffs, but when you are doing copy
4479         * detection you would need them, so here they are"
4480         * entries to the diff-core.  They will be prefixed
4481         * with something like '=' or '*' (I haven't decided
4482         * which but should not make any difference).
4483         * Feeding the same new and old to diff_change()
4484         * also has the same effect.
4485         * Before the final output happens, they are pruned after
4486         * merged into rename/copy pairs as appropriate.
4487         */
4488        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4489                addremove = (addremove == '+' ? '-' :
4490                             addremove == '-' ? '+' : addremove);
4491
4492        if (options->prefix &&
4493            strncmp(concatpath, options->prefix, options->prefix_length))
4494                return;
4495
4496        one = alloc_filespec(concatpath);
4497        two = alloc_filespec(concatpath);
4498
4499        if (addremove != '+')
4500                fill_filespec(one, sha1, mode);
4501        if (addremove != '-') {
4502                fill_filespec(two, sha1, mode);
4503                two->dirty_submodule = dirty_submodule;
4504        }
4505
4506        diff_queue(&diff_queued_diff, one, two);
4507        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4508                DIFF_OPT_SET(options, HAS_CHANGES);
4509}
4510
4511void diff_change(struct diff_options *options,
4512                 unsigned old_mode, unsigned new_mode,
4513                 const unsigned char *old_sha1,
4514                 const unsigned char *new_sha1,
4515                 const char *concatpath,
4516                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4517{
4518        struct diff_filespec *one, *two;
4519
4520        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4521            is_submodule_ignored(concatpath, options))
4522                return;
4523
4524        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4525                unsigned tmp;
4526                const unsigned char *tmp_c;
4527                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4528                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4529                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4530                        new_dirty_submodule = tmp;
4531        }
4532
4533        if (options->prefix &&
4534            strncmp(concatpath, options->prefix, options->prefix_length))
4535                return;
4536
4537        one = alloc_filespec(concatpath);
4538        two = alloc_filespec(concatpath);
4539        fill_filespec(one, old_sha1, old_mode);
4540        fill_filespec(two, new_sha1, new_mode);
4541        one->dirty_submodule = old_dirty_submodule;
4542        two->dirty_submodule = new_dirty_submodule;
4543
4544        diff_queue(&diff_queued_diff, one, two);
4545        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4546                DIFF_OPT_SET(options, HAS_CHANGES);
4547}
4548
4549struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4550{
4551        struct diff_filepair *pair;
4552        struct diff_filespec *one, *two;
4553
4554        if (options->prefix &&
4555            strncmp(path, options->prefix, options->prefix_length))
4556                return NULL;
4557
4558        one = alloc_filespec(path);
4559        two = alloc_filespec(path);
4560        pair = diff_queue(&diff_queued_diff, one, two);
4561        pair->is_unmerged = 1;
4562        return pair;
4563}
4564
4565static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4566                size_t *outsize)
4567{
4568        struct diff_tempfile *temp;
4569        const char *argv[3];
4570        const char **arg = argv;
4571        struct child_process child;
4572        struct strbuf buf = STRBUF_INIT;
4573        int err = 0;
4574
4575        temp = prepare_temp_file(spec->path, spec);
4576        *arg++ = pgm;
4577        *arg++ = temp->name;
4578        *arg = NULL;
4579
4580        memset(&child, 0, sizeof(child));
4581        child.use_shell = 1;
4582        child.argv = argv;
4583        child.out = -1;
4584        if (start_command(&child)) {
4585                remove_tempfile();
4586                return NULL;
4587        }
4588
4589        if (strbuf_read(&buf, child.out, 0) < 0)
4590                err = error("error reading from textconv command '%s'", pgm);
4591        close(child.out);
4592
4593        if (finish_command(&child) || err) {
4594                strbuf_release(&buf);
4595                remove_tempfile();
4596                return NULL;
4597        }
4598        remove_tempfile();
4599
4600        return strbuf_detach(&buf, outsize);
4601}
4602
4603size_t fill_textconv(struct userdiff_driver *driver,
4604                     struct diff_filespec *df,
4605                     char **outbuf)
4606{
4607        size_t size;
4608
4609        if (!driver || !driver->textconv) {
4610                if (!DIFF_FILE_VALID(df)) {
4611                        *outbuf = "";
4612                        return 0;
4613                }
4614                if (diff_populate_filespec(df, 0))
4615                        die("unable to read files to diff");
4616                *outbuf = df->data;
4617                return df->size;
4618        }
4619
4620        if (driver->textconv_cache && df->sha1_valid) {
4621                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4622                                          &size);
4623                if (*outbuf)
4624                        return size;
4625        }
4626
4627        *outbuf = run_textconv(driver->textconv, df, &size);
4628        if (!*outbuf)
4629                die("unable to read files to diff");
4630
4631        if (driver->textconv_cache && df->sha1_valid) {
4632                /* ignore errors, as we might be in a readonly repository */
4633                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4634                                size);
4635                /*
4636                 * we could save up changes and flush them all at the end,
4637                 * but we would need an extra call after all diffing is done.
4638                 * Since generating a cache entry is the slow path anyway,
4639                 * this extra overhead probably isn't a big deal.
4640                 */
4641                notes_cache_write(driver->textconv_cache);
4642        }
4643
4644        return size;
4645}