diff.con commit Merge branch 'js/rebase-typo-branch-squelch-usage' (5527257)
   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, -1);
 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        int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 587        const char *name_a_tab, *name_b_tab;
 588        const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 589        const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 590        const char *reset = diff_get_color(color_diff, DIFF_RESET);
 591        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 592        const char *a_prefix, *b_prefix;
 593        char *data_one, *data_two;
 594        size_t size_one, size_two;
 595        struct emit_callback ecbdata;
 596        char *line_prefix = "";
 597        struct strbuf *msgbuf;
 598
 599        if (o && o->output_prefix) {
 600                msgbuf = o->output_prefix(o, o->output_prefix_data);
 601                line_prefix = msgbuf->buf;
 602        }
 603
 604        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 605                a_prefix = o->b_prefix;
 606                b_prefix = o->a_prefix;
 607        } else {
 608                a_prefix = o->a_prefix;
 609                b_prefix = o->b_prefix;
 610        }
 611
 612        name_a += (*name_a == '/');
 613        name_b += (*name_b == '/');
 614        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 615        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 616
 617        strbuf_reset(&a_name);
 618        strbuf_reset(&b_name);
 619        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 620        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 621
 622        size_one = fill_textconv(textconv_one, one, &data_one);
 623        size_two = fill_textconv(textconv_two, two, &data_two);
 624
 625        memset(&ecbdata, 0, sizeof(ecbdata));
 626        ecbdata.color_diff = color_diff;
 627        ecbdata.found_changesp = &o->found_changes;
 628        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 629        ecbdata.opt = o;
 630        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 631                mmfile_t mf1, mf2;
 632                mf1.ptr = (char *)data_one;
 633                mf2.ptr = (char *)data_two;
 634                mf1.size = size_one;
 635                mf2.size = size_two;
 636                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 637        }
 638        ecbdata.lno_in_preimage = 1;
 639        ecbdata.lno_in_postimage = 1;
 640
 641        lc_a = count_lines(data_one, size_one);
 642        lc_b = count_lines(data_two, size_two);
 643        fprintf(o->file,
 644                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 645                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 646                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 647                line_prefix, fraginfo);
 648        if (!o->irreversible_delete)
 649                print_line_count(o->file, lc_a);
 650        else
 651                fprintf(o->file, "?,?");
 652        fprintf(o->file, " +");
 653        print_line_count(o->file, lc_b);
 654        fprintf(o->file, " @@%s\n", reset);
 655        if (lc_a && !o->irreversible_delete)
 656                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 657        if (lc_b)
 658                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 659        if (textconv_one)
 660                free((char *)data_one);
 661        if (textconv_two)
 662                free((char *)data_two);
 663}
 664
 665struct diff_words_buffer {
 666        mmfile_t text;
 667        long alloc;
 668        struct diff_words_orig {
 669                const char *begin, *end;
 670        } *orig;
 671        int orig_nr, orig_alloc;
 672};
 673
 674static void diff_words_append(char *line, unsigned long len,
 675                struct diff_words_buffer *buffer)
 676{
 677        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 678        line++;
 679        len--;
 680        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 681        buffer->text.size += len;
 682        buffer->text.ptr[buffer->text.size] = '\0';
 683}
 684
 685struct diff_words_style_elem {
 686        const char *prefix;
 687        const char *suffix;
 688        const char *color; /* NULL; filled in by the setup code if
 689                            * color is enabled */
 690};
 691
 692struct diff_words_style {
 693        enum diff_words_type type;
 694        struct diff_words_style_elem new, old, ctx;
 695        const char *newline;
 696};
 697
 698static struct diff_words_style diff_words_styles[] = {
 699        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 700        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 701        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 702};
 703
 704struct diff_words_data {
 705        struct diff_words_buffer minus, plus;
 706        const char *current_plus;
 707        int last_minus;
 708        struct diff_options *opt;
 709        regex_t *word_regex;
 710        enum diff_words_type type;
 711        struct diff_words_style *style;
 712};
 713
 714static int fn_out_diff_words_write_helper(FILE *fp,
 715                                          struct diff_words_style_elem *st_el,
 716                                          const char *newline,
 717                                          size_t count, const char *buf,
 718                                          const char *line_prefix)
 719{
 720        int print = 0;
 721
 722        while (count) {
 723                char *p = memchr(buf, '\n', count);
 724                if (print)
 725                        fputs(line_prefix, fp);
 726                if (p != buf) {
 727                        if (st_el->color && fputs(st_el->color, fp) < 0)
 728                                return -1;
 729                        if (fputs(st_el->prefix, fp) < 0 ||
 730                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 731                            fputs(st_el->suffix, fp) < 0)
 732                                return -1;
 733                        if (st_el->color && *st_el->color
 734                            && fputs(GIT_COLOR_RESET, fp) < 0)
 735                                return -1;
 736                }
 737                if (!p)
 738                        return 0;
 739                if (fputs(newline, fp) < 0)
 740                        return -1;
 741                count -= p + 1 - buf;
 742                buf = p + 1;
 743                print = 1;
 744        }
 745        return 0;
 746}
 747
 748/*
 749 * '--color-words' algorithm can be described as:
 750 *
 751 *   1. collect a the minus/plus lines of a diff hunk, divided into
 752 *      minus-lines and plus-lines;
 753 *
 754 *   2. break both minus-lines and plus-lines into words and
 755 *      place them into two mmfile_t with one word for each line;
 756 *
 757 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 758 *
 759 * And for the common parts of the both file, we output the plus side text.
 760 * diff_words->current_plus is used to trace the current position of the plus file
 761 * which printed. diff_words->last_minus is used to trace the last minus word
 762 * printed.
 763 *
 764 * For '--graph' to work with '--color-words', we need to output the graph prefix
 765 * on each line of color words output. Generally, there are two conditions on
 766 * which we should output the prefix.
 767 *
 768 *   1. diff_words->last_minus == 0 &&
 769 *      diff_words->current_plus == diff_words->plus.text.ptr
 770 *
 771 *      that is: the plus text must start as a new line, and if there is no minus
 772 *      word printed, a graph prefix must be printed.
 773 *
 774 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 775 *      *(diff_words->current_plus - 1) == '\n'
 776 *
 777 *      that is: a graph prefix must be printed following a '\n'
 778 */
 779static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 780{
 781        if ((diff_words->last_minus == 0 &&
 782                diff_words->current_plus == diff_words->plus.text.ptr) ||
 783                (diff_words->current_plus > diff_words->plus.text.ptr &&
 784                *(diff_words->current_plus - 1) == '\n')) {
 785                return 1;
 786        } else {
 787                return 0;
 788        }
 789}
 790
 791static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 792{
 793        struct diff_words_data *diff_words = priv;
 794        struct diff_words_style *style = diff_words->style;
 795        int minus_first, minus_len, plus_first, plus_len;
 796        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 797        struct diff_options *opt = diff_words->opt;
 798        struct strbuf *msgbuf;
 799        char *line_prefix = "";
 800
 801        if (line[0] != '@' || parse_hunk_header(line, len,
 802                        &minus_first, &minus_len, &plus_first, &plus_len))
 803                return;
 804
 805        assert(opt);
 806        if (opt->output_prefix) {
 807                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 808                line_prefix = msgbuf->buf;
 809        }
 810
 811        /* POSIX requires that first be decremented by one if len == 0... */
 812        if (minus_len) {
 813                minus_begin = diff_words->minus.orig[minus_first].begin;
 814                minus_end =
 815                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 816        } else
 817                minus_begin = minus_end =
 818                        diff_words->minus.orig[minus_first].end;
 819
 820        if (plus_len) {
 821                plus_begin = diff_words->plus.orig[plus_first].begin;
 822                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 823        } else
 824                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 825
 826        if (color_words_output_graph_prefix(diff_words)) {
 827                fputs(line_prefix, diff_words->opt->file);
 828        }
 829        if (diff_words->current_plus != plus_begin) {
 830                fn_out_diff_words_write_helper(diff_words->opt->file,
 831                                &style->ctx, style->newline,
 832                                plus_begin - diff_words->current_plus,
 833                                diff_words->current_plus, line_prefix);
 834                if (*(plus_begin - 1) == '\n')
 835                        fputs(line_prefix, diff_words->opt->file);
 836        }
 837        if (minus_begin != minus_end) {
 838                fn_out_diff_words_write_helper(diff_words->opt->file,
 839                                &style->old, style->newline,
 840                                minus_end - minus_begin, minus_begin,
 841                                line_prefix);
 842        }
 843        if (plus_begin != plus_end) {
 844                fn_out_diff_words_write_helper(diff_words->opt->file,
 845                                &style->new, style->newline,
 846                                plus_end - plus_begin, plus_begin,
 847                                line_prefix);
 848        }
 849
 850        diff_words->current_plus = plus_end;
 851        diff_words->last_minus = minus_first;
 852}
 853
 854/* This function starts looking at *begin, and returns 0 iff a word was found. */
 855static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 856                int *begin, int *end)
 857{
 858        if (word_regex && *begin < buffer->size) {
 859                regmatch_t match[1];
 860                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 861                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 862                                        '\n', match[0].rm_eo - match[0].rm_so);
 863                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 864                        *begin += match[0].rm_so;
 865                        return *begin >= *end;
 866                }
 867                return -1;
 868        }
 869
 870        /* find the next word */
 871        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 872                (*begin)++;
 873        if (*begin >= buffer->size)
 874                return -1;
 875
 876        /* find the end of the word */
 877        *end = *begin + 1;
 878        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 879                (*end)++;
 880
 881        return 0;
 882}
 883
 884/*
 885 * This function splits the words in buffer->text, stores the list with
 886 * newline separator into out, and saves the offsets of the original words
 887 * in buffer->orig.
 888 */
 889static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 890                regex_t *word_regex)
 891{
 892        int i, j;
 893        long alloc = 0;
 894
 895        out->size = 0;
 896        out->ptr = NULL;
 897
 898        /* fake an empty "0th" word */
 899        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 900        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 901        buffer->orig_nr = 1;
 902
 903        for (i = 0; i < buffer->text.size; i++) {
 904                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 905                        return;
 906
 907                /* store original boundaries */
 908                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 909                                buffer->orig_alloc);
 910                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 911                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 912                buffer->orig_nr++;
 913
 914                /* store one word */
 915                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 916                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 917                out->ptr[out->size + j - i] = '\n';
 918                out->size += j - i + 1;
 919
 920                i = j - 1;
 921        }
 922}
 923
 924/* this executes the word diff on the accumulated buffers */
 925static void diff_words_show(struct diff_words_data *diff_words)
 926{
 927        xpparam_t xpp;
 928        xdemitconf_t xecfg;
 929        mmfile_t minus, plus;
 930        struct diff_words_style *style = diff_words->style;
 931
 932        struct diff_options *opt = diff_words->opt;
 933        struct strbuf *msgbuf;
 934        char *line_prefix = "";
 935
 936        assert(opt);
 937        if (opt->output_prefix) {
 938                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 939                line_prefix = msgbuf->buf;
 940        }
 941
 942        /* special case: only removal */
 943        if (!diff_words->plus.text.size) {
 944                fputs(line_prefix, diff_words->opt->file);
 945                fn_out_diff_words_write_helper(diff_words->opt->file,
 946                        &style->old, style->newline,
 947                        diff_words->minus.text.size,
 948                        diff_words->minus.text.ptr, line_prefix);
 949                diff_words->minus.text.size = 0;
 950                return;
 951        }
 952
 953        diff_words->current_plus = diff_words->plus.text.ptr;
 954        diff_words->last_minus = 0;
 955
 956        memset(&xpp, 0, sizeof(xpp));
 957        memset(&xecfg, 0, sizeof(xecfg));
 958        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 959        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 960        xpp.flags = 0;
 961        /* as only the hunk header will be parsed, we need a 0-context */
 962        xecfg.ctxlen = 0;
 963        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 964                      &xpp, &xecfg);
 965        free(minus.ptr);
 966        free(plus.ptr);
 967        if (diff_words->current_plus != diff_words->plus.text.ptr +
 968                        diff_words->plus.text.size) {
 969                if (color_words_output_graph_prefix(diff_words))
 970                        fputs(line_prefix, diff_words->opt->file);
 971                fn_out_diff_words_write_helper(diff_words->opt->file,
 972                        &style->ctx, style->newline,
 973                        diff_words->plus.text.ptr + diff_words->plus.text.size
 974                        - diff_words->current_plus, diff_words->current_plus,
 975                        line_prefix);
 976        }
 977        diff_words->minus.text.size = diff_words->plus.text.size = 0;
 978}
 979
 980/* In "color-words" mode, show word-diff of words accumulated in the buffer */
 981static void diff_words_flush(struct emit_callback *ecbdata)
 982{
 983        if (ecbdata->diff_words->minus.text.size ||
 984            ecbdata->diff_words->plus.text.size)
 985                diff_words_show(ecbdata->diff_words);
 986}
 987
 988static void free_diff_words_data(struct emit_callback *ecbdata)
 989{
 990        if (ecbdata->diff_words) {
 991                diff_words_flush(ecbdata);
 992                free (ecbdata->diff_words->minus.text.ptr);
 993                free (ecbdata->diff_words->minus.orig);
 994                free (ecbdata->diff_words->plus.text.ptr);
 995                free (ecbdata->diff_words->plus.orig);
 996                if (ecbdata->diff_words->word_regex) {
 997                        regfree(ecbdata->diff_words->word_regex);
 998                        free(ecbdata->diff_words->word_regex);
 999                }
1000                free(ecbdata->diff_words);
1001                ecbdata->diff_words = NULL;
1002        }
1003}
1004
1005const char *diff_get_color(int diff_use_color, enum color_diff ix)
1006{
1007        if (diff_use_color)
1008                return diff_colors[ix];
1009        return "";
1010}
1011
1012static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1013{
1014        const char *cp;
1015        unsigned long allot;
1016        size_t l = len;
1017
1018        if (ecb->truncate)
1019                return ecb->truncate(line, len);
1020        cp = line;
1021        allot = l;
1022        while (0 < l) {
1023                (void) utf8_width(&cp, &l);
1024                if (!cp)
1025                        break; /* truncated in the middle? */
1026        }
1027        return allot - l;
1028}
1029
1030static void find_lno(const char *line, struct emit_callback *ecbdata)
1031{
1032        const char *p;
1033        ecbdata->lno_in_preimage = 0;
1034        ecbdata->lno_in_postimage = 0;
1035        p = strchr(line, '-');
1036        if (!p)
1037                return; /* cannot happen */
1038        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1039        p = strchr(p, '+');
1040        if (!p)
1041                return; /* cannot happen */
1042        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1043}
1044
1045static void fn_out_consume(void *priv, char *line, unsigned long len)
1046{
1047        struct emit_callback *ecbdata = priv;
1048        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1049        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1050        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1051        struct diff_options *o = ecbdata->opt;
1052        char *line_prefix = "";
1053        struct strbuf *msgbuf;
1054
1055        if (o && o->output_prefix) {
1056                msgbuf = o->output_prefix(o, o->output_prefix_data);
1057                line_prefix = msgbuf->buf;
1058        }
1059
1060        if (ecbdata->header) {
1061                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1062                strbuf_reset(ecbdata->header);
1063                ecbdata->header = NULL;
1064        }
1065        *(ecbdata->found_changesp) = 1;
1066
1067        if (ecbdata->label_path[0]) {
1068                const char *name_a_tab, *name_b_tab;
1069
1070                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1071                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1072
1073                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1074                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1075                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1076                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1077                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1078        }
1079
1080        if (diff_suppress_blank_empty
1081            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1082                line[0] = '\n';
1083                len = 1;
1084        }
1085
1086        if (line[0] == '@') {
1087                if (ecbdata->diff_words)
1088                        diff_words_flush(ecbdata);
1089                len = sane_truncate_line(ecbdata, line, len);
1090                find_lno(line, ecbdata);
1091                emit_hunk_header(ecbdata, line, len);
1092                if (line[len-1] != '\n')
1093                        putc('\n', ecbdata->opt->file);
1094                return;
1095        }
1096
1097        if (len < 1) {
1098                emit_line(ecbdata->opt, reset, reset, line, len);
1099                if (ecbdata->diff_words
1100                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1101                        fputs("~\n", ecbdata->opt->file);
1102                return;
1103        }
1104
1105        if (ecbdata->diff_words) {
1106                if (line[0] == '-') {
1107                        diff_words_append(line, len,
1108                                          &ecbdata->diff_words->minus);
1109                        return;
1110                } else if (line[0] == '+') {
1111                        diff_words_append(line, len,
1112                                          &ecbdata->diff_words->plus);
1113                        return;
1114                }
1115                diff_words_flush(ecbdata);
1116                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1117                        emit_line(ecbdata->opt, plain, reset, line, len);
1118                        fputs("~\n", ecbdata->opt->file);
1119                } else {
1120                        /*
1121                         * Skip the prefix character, if any.  With
1122                         * diff_suppress_blank_empty, there may be
1123                         * none.
1124                         */
1125                        if (line[0] != '\n') {
1126                              line++;
1127                              len--;
1128                        }
1129                        emit_line(ecbdata->opt, plain, reset, line, len);
1130                }
1131                return;
1132        }
1133
1134        if (line[0] != '+') {
1135                const char *color =
1136                        diff_get_color(ecbdata->color_diff,
1137                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1138                ecbdata->lno_in_preimage++;
1139                if (line[0] == ' ')
1140                        ecbdata->lno_in_postimage++;
1141                emit_line(ecbdata->opt, color, reset, line, len);
1142        } else {
1143                ecbdata->lno_in_postimage++;
1144                emit_add_line(reset, ecbdata, line + 1, len - 1);
1145        }
1146}
1147
1148static char *pprint_rename(const char *a, const char *b)
1149{
1150        const char *old = a;
1151        const char *new = b;
1152        struct strbuf name = STRBUF_INIT;
1153        int pfx_length, sfx_length;
1154        int len_a = strlen(a);
1155        int len_b = strlen(b);
1156        int a_midlen, b_midlen;
1157        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1158        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1159
1160        if (qlen_a || qlen_b) {
1161                quote_c_style(a, &name, NULL, 0);
1162                strbuf_addstr(&name, " => ");
1163                quote_c_style(b, &name, NULL, 0);
1164                return strbuf_detach(&name, NULL);
1165        }
1166
1167        /* Find common prefix */
1168        pfx_length = 0;
1169        while (*old && *new && *old == *new) {
1170                if (*old == '/')
1171                        pfx_length = old - a + 1;
1172                old++;
1173                new++;
1174        }
1175
1176        /* Find common suffix */
1177        old = a + len_a;
1178        new = b + len_b;
1179        sfx_length = 0;
1180        while (a <= old && b <= new && *old == *new) {
1181                if (*old == '/')
1182                        sfx_length = len_a - (old - a);
1183                old--;
1184                new--;
1185        }
1186
1187        /*
1188         * pfx{mid-a => mid-b}sfx
1189         * {pfx-a => pfx-b}sfx
1190         * pfx{sfx-a => sfx-b}
1191         * name-a => name-b
1192         */
1193        a_midlen = len_a - pfx_length - sfx_length;
1194        b_midlen = len_b - pfx_length - sfx_length;
1195        if (a_midlen < 0)
1196                a_midlen = 0;
1197        if (b_midlen < 0)
1198                b_midlen = 0;
1199
1200        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1201        if (pfx_length + sfx_length) {
1202                strbuf_add(&name, a, pfx_length);
1203                strbuf_addch(&name, '{');
1204        }
1205        strbuf_add(&name, a + pfx_length, a_midlen);
1206        strbuf_addstr(&name, " => ");
1207        strbuf_add(&name, b + pfx_length, b_midlen);
1208        if (pfx_length + sfx_length) {
1209                strbuf_addch(&name, '}');
1210                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1211        }
1212        return strbuf_detach(&name, NULL);
1213}
1214
1215struct diffstat_t {
1216        int nr;
1217        int alloc;
1218        struct diffstat_file {
1219                char *from_name;
1220                char *name;
1221                char *print_name;
1222                unsigned is_unmerged:1;
1223                unsigned is_binary:1;
1224                unsigned is_renamed:1;
1225                uintmax_t added, deleted;
1226        } **files;
1227};
1228
1229static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1230                                          const char *name_a,
1231                                          const char *name_b)
1232{
1233        struct diffstat_file *x;
1234        x = xcalloc(sizeof (*x), 1);
1235        if (diffstat->nr == diffstat->alloc) {
1236                diffstat->alloc = alloc_nr(diffstat->alloc);
1237                diffstat->files = xrealloc(diffstat->files,
1238                                diffstat->alloc * sizeof(x));
1239        }
1240        diffstat->files[diffstat->nr++] = x;
1241        if (name_b) {
1242                x->from_name = xstrdup(name_a);
1243                x->name = xstrdup(name_b);
1244                x->is_renamed = 1;
1245        }
1246        else {
1247                x->from_name = NULL;
1248                x->name = xstrdup(name_a);
1249        }
1250        return x;
1251}
1252
1253static void diffstat_consume(void *priv, char *line, unsigned long len)
1254{
1255        struct diffstat_t *diffstat = priv;
1256        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1257
1258        if (line[0] == '+')
1259                x->added++;
1260        else if (line[0] == '-')
1261                x->deleted++;
1262}
1263
1264const char mime_boundary_leader[] = "------------";
1265
1266static int scale_linear(int it, int width, int max_change)
1267{
1268        /*
1269         * make sure that at least one '-' is printed if there were deletions,
1270         * and likewise for '+'.
1271         */
1272        if (max_change < 2)
1273                return it;
1274        return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
1275}
1276
1277static void show_name(FILE *file,
1278                      const char *prefix, const char *name, int len)
1279{
1280        fprintf(file, " %s%-*s |", prefix, len, name);
1281}
1282
1283static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1284{
1285        if (cnt <= 0)
1286                return;
1287        fprintf(file, "%s", set);
1288        while (cnt--)
1289                putc(ch, file);
1290        fprintf(file, "%s", reset);
1291}
1292
1293static void fill_print_name(struct diffstat_file *file)
1294{
1295        char *pname;
1296
1297        if (file->print_name)
1298                return;
1299
1300        if (!file->is_renamed) {
1301                struct strbuf buf = STRBUF_INIT;
1302                if (quote_c_style(file->name, &buf, NULL, 0)) {
1303                        pname = strbuf_detach(&buf, NULL);
1304                } else {
1305                        pname = file->name;
1306                        strbuf_release(&buf);
1307                }
1308        } else {
1309                pname = pprint_rename(file->from_name, file->name);
1310        }
1311        file->print_name = pname;
1312}
1313
1314static void show_stats(struct diffstat_t *data, struct diff_options *options)
1315{
1316        int i, len, add, del, adds = 0, dels = 0;
1317        uintmax_t max_change = 0, max_len = 0;
1318        int total_files = data->nr;
1319        int width, name_width, count;
1320        const char *reset, *add_c, *del_c;
1321        const char *line_prefix = "";
1322        int extra_shown = 0;
1323        struct strbuf *msg = NULL;
1324
1325        if (data->nr == 0)
1326                return;
1327
1328        if (options->output_prefix) {
1329                msg = options->output_prefix(options, options->output_prefix_data);
1330                line_prefix = msg->buf;
1331        }
1332
1333        width = options->stat_width ? options->stat_width : 80;
1334        name_width = options->stat_name_width ? options->stat_name_width : 50;
1335        count = options->stat_count ? options->stat_count : data->nr;
1336
1337        /* Sanity: give at least 5 columns to the graph,
1338         * but leave at least 10 columns for the name.
1339         */
1340        if (width < 25)
1341                width = 25;
1342        if (name_width < 10)
1343                name_width = 10;
1344        else if (width < name_width + 15)
1345                name_width = width - 15;
1346
1347        /* Find the longest filename and max number of changes */
1348        reset = diff_get_color_opt(options, DIFF_RESET);
1349        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1350        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1351
1352        for (i = 0; (i < count) && (i < data->nr); i++) {
1353                struct diffstat_file *file = data->files[i];
1354                uintmax_t change = file->added + file->deleted;
1355                if (!data->files[i]->is_renamed &&
1356                         (change == 0)) {
1357                        count++; /* not shown == room for one more */
1358                        continue;
1359                }
1360                fill_print_name(file);
1361                len = strlen(file->print_name);
1362                if (max_len < len)
1363                        max_len = len;
1364
1365                if (file->is_binary || file->is_unmerged)
1366                        continue;
1367                if (max_change < change)
1368                        max_change = change;
1369        }
1370        count = i; /* min(count, data->nr) */
1371
1372        /* Compute the width of the graph part;
1373         * 10 is for one blank at the beginning of the line plus
1374         * " | count " between the name and the graph.
1375         *
1376         * From here on, name_width is the width of the name area,
1377         * and width is the width of the graph area.
1378         */
1379        name_width = (name_width < max_len) ? name_width : max_len;
1380        if (width < (name_width + 10) + max_change)
1381                width = width - (name_width + 10);
1382        else
1383                width = max_change;
1384
1385        for (i = 0; i < count; i++) {
1386                const char *prefix = "";
1387                char *name = data->files[i]->print_name;
1388                uintmax_t added = data->files[i]->added;
1389                uintmax_t deleted = data->files[i]->deleted;
1390                int name_len;
1391
1392                if (!data->files[i]->is_renamed &&
1393                         (added + deleted == 0)) {
1394                        total_files--;
1395                        continue;
1396                }
1397                /*
1398                 * "scale" the filename
1399                 */
1400                len = name_width;
1401                name_len = strlen(name);
1402                if (name_width < name_len) {
1403                        char *slash;
1404                        prefix = "...";
1405                        len -= 3;
1406                        name += name_len - len;
1407                        slash = strchr(name, '/');
1408                        if (slash)
1409                                name = slash;
1410                }
1411
1412                if (data->files[i]->is_binary) {
1413                        fprintf(options->file, "%s", line_prefix);
1414                        show_name(options->file, prefix, name, len);
1415                        fprintf(options->file, "  Bin ");
1416                        fprintf(options->file, "%s%"PRIuMAX"%s",
1417                                del_c, deleted, reset);
1418                        fprintf(options->file, " -> ");
1419                        fprintf(options->file, "%s%"PRIuMAX"%s",
1420                                add_c, added, reset);
1421                        fprintf(options->file, " bytes");
1422                        fprintf(options->file, "\n");
1423                        continue;
1424                }
1425                else if (data->files[i]->is_unmerged) {
1426                        fprintf(options->file, "%s", line_prefix);
1427                        show_name(options->file, prefix, name, len);
1428                        fprintf(options->file, "  Unmerged\n");
1429                        continue;
1430                }
1431
1432                /*
1433                 * scale the add/delete
1434                 */
1435                add = added;
1436                del = deleted;
1437                adds += add;
1438                dels += del;
1439
1440                if (width <= max_change) {
1441                        add = scale_linear(add, width, max_change);
1442                        del = scale_linear(del, width, max_change);
1443                }
1444                fprintf(options->file, "%s", line_prefix);
1445                show_name(options->file, prefix, name, len);
1446                fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
1447                                added + deleted ? " " : "");
1448                show_graph(options->file, '+', add, add_c, reset);
1449                show_graph(options->file, '-', del, del_c, reset);
1450                fprintf(options->file, "\n");
1451        }
1452        for (i = count; i < data->nr; i++) {
1453                uintmax_t added = data->files[i]->added;
1454                uintmax_t deleted = data->files[i]->deleted;
1455                if (!data->files[i]->is_renamed &&
1456                         (added + deleted == 0)) {
1457                        total_files--;
1458                        continue;
1459                }
1460                adds += added;
1461                dels += deleted;
1462                if (!extra_shown)
1463                        fprintf(options->file, "%s ...\n", line_prefix);
1464                extra_shown = 1;
1465        }
1466        fprintf(options->file, "%s", line_prefix);
1467        fprintf(options->file,
1468               " %d files changed, %d insertions(+), %d deletions(-)\n",
1469               total_files, adds, dels);
1470}
1471
1472static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1473{
1474        int i, adds = 0, dels = 0, total_files = data->nr;
1475
1476        if (data->nr == 0)
1477                return;
1478
1479        for (i = 0; i < data->nr; i++) {
1480                if (!data->files[i]->is_binary &&
1481                    !data->files[i]->is_unmerged) {
1482                        int added = data->files[i]->added;
1483                        int deleted= data->files[i]->deleted;
1484                        if (!data->files[i]->is_renamed &&
1485                            (added + deleted == 0)) {
1486                                total_files--;
1487                        } else {
1488                                adds += added;
1489                                dels += deleted;
1490                        }
1491                }
1492        }
1493        if (options->output_prefix) {
1494                struct strbuf *msg = NULL;
1495                msg = options->output_prefix(options,
1496                                options->output_prefix_data);
1497                fprintf(options->file, "%s", msg->buf);
1498        }
1499        fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
1500               total_files, adds, dels);
1501}
1502
1503static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1504{
1505        int i;
1506
1507        if (data->nr == 0)
1508                return;
1509
1510        for (i = 0; i < data->nr; i++) {
1511                struct diffstat_file *file = data->files[i];
1512
1513                if (options->output_prefix) {
1514                        struct strbuf *msg = NULL;
1515                        msg = options->output_prefix(options,
1516                                        options->output_prefix_data);
1517                        fprintf(options->file, "%s", msg->buf);
1518                }
1519
1520                if (file->is_binary)
1521                        fprintf(options->file, "-\t-\t");
1522                else
1523                        fprintf(options->file,
1524                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1525                                file->added, file->deleted);
1526                if (options->line_termination) {
1527                        fill_print_name(file);
1528                        if (!file->is_renamed)
1529                                write_name_quoted(file->name, options->file,
1530                                                  options->line_termination);
1531                        else {
1532                                fputs(file->print_name, options->file);
1533                                putc(options->line_termination, options->file);
1534                        }
1535                } else {
1536                        if (file->is_renamed) {
1537                                putc('\0', options->file);
1538                                write_name_quoted(file->from_name, options->file, '\0');
1539                        }
1540                        write_name_quoted(file->name, options->file, '\0');
1541                }
1542        }
1543}
1544
1545struct dirstat_file {
1546        const char *name;
1547        unsigned long changed;
1548};
1549
1550struct dirstat_dir {
1551        struct dirstat_file *files;
1552        int alloc, nr, permille, cumulative;
1553};
1554
1555static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1556                unsigned long changed, const char *base, int baselen)
1557{
1558        unsigned long this_dir = 0;
1559        unsigned int sources = 0;
1560        const char *line_prefix = "";
1561        struct strbuf *msg = NULL;
1562
1563        if (opt->output_prefix) {
1564                msg = opt->output_prefix(opt, opt->output_prefix_data);
1565                line_prefix = msg->buf;
1566        }
1567
1568        while (dir->nr) {
1569                struct dirstat_file *f = dir->files;
1570                int namelen = strlen(f->name);
1571                unsigned long this;
1572                char *slash;
1573
1574                if (namelen < baselen)
1575                        break;
1576                if (memcmp(f->name, base, baselen))
1577                        break;
1578                slash = strchr(f->name + baselen, '/');
1579                if (slash) {
1580                        int newbaselen = slash + 1 - f->name;
1581                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1582                        sources++;
1583                } else {
1584                        this = f->changed;
1585                        dir->files++;
1586                        dir->nr--;
1587                        sources += 2;
1588                }
1589                this_dir += this;
1590        }
1591
1592        /*
1593         * We don't report dirstat's for
1594         *  - the top level
1595         *  - or cases where everything came from a single directory
1596         *    under this directory (sources == 1).
1597         */
1598        if (baselen && sources != 1) {
1599                if (this_dir) {
1600                        int permille = this_dir * 1000 / changed;
1601                        if (permille >= dir->permille) {
1602                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1603                                        permille / 10, permille % 10, baselen, base);
1604                                if (!dir->cumulative)
1605                                        return 0;
1606                        }
1607                }
1608        }
1609        return this_dir;
1610}
1611
1612static int dirstat_compare(const void *_a, const void *_b)
1613{
1614        const struct dirstat_file *a = _a;
1615        const struct dirstat_file *b = _b;
1616        return strcmp(a->name, b->name);
1617}
1618
1619static void show_dirstat(struct diff_options *options)
1620{
1621        int i;
1622        unsigned long changed;
1623        struct dirstat_dir dir;
1624        struct diff_queue_struct *q = &diff_queued_diff;
1625
1626        dir.files = NULL;
1627        dir.alloc = 0;
1628        dir.nr = 0;
1629        dir.permille = options->dirstat_permille;
1630        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1631
1632        changed = 0;
1633        for (i = 0; i < q->nr; i++) {
1634                struct diff_filepair *p = q->queue[i];
1635                const char *name;
1636                unsigned long copied, added, damage;
1637                int content_changed;
1638
1639                name = p->two->path ? p->two->path : p->one->path;
1640
1641                if (p->one->sha1_valid && p->two->sha1_valid)
1642                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1643                else
1644                        content_changed = 1;
1645
1646                if (!content_changed) {
1647                        /*
1648                         * The SHA1 has not changed, so pre-/post-content is
1649                         * identical. We can therefore skip looking at the
1650                         * file contents altogether.
1651                         */
1652                        damage = 0;
1653                        goto found_damage;
1654                }
1655
1656                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1657                        /*
1658                         * In --dirstat-by-file mode, we don't really need to
1659                         * look at the actual file contents at all.
1660                         * The fact that the SHA1 changed is enough for us to
1661                         * add this file to the list of results
1662                         * (with each file contributing equal damage).
1663                         */
1664                        damage = 1;
1665                        goto found_damage;
1666                }
1667
1668                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1669                        diff_populate_filespec(p->one, 0);
1670                        diff_populate_filespec(p->two, 0);
1671                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1672                                               &copied, &added);
1673                        diff_free_filespec_data(p->one);
1674                        diff_free_filespec_data(p->two);
1675                } else if (DIFF_FILE_VALID(p->one)) {
1676                        diff_populate_filespec(p->one, 1);
1677                        copied = added = 0;
1678                        diff_free_filespec_data(p->one);
1679                } else if (DIFF_FILE_VALID(p->two)) {
1680                        diff_populate_filespec(p->two, 1);
1681                        copied = 0;
1682                        added = p->two->size;
1683                        diff_free_filespec_data(p->two);
1684                } else
1685                        continue;
1686
1687                /*
1688                 * Original minus copied is the removed material,
1689                 * added is the new material.  They are both damages
1690                 * made to the preimage.
1691                 * If the resulting damage is zero, we know that
1692                 * diffcore_count_changes() considers the two entries to
1693                 * be identical, but since content_changed is true, we
1694                 * know that there must have been _some_ kind of change,
1695                 * so we force all entries to have damage > 0.
1696                 */
1697                damage = (p->one->size - copied) + added;
1698                if (!damage)
1699                        damage = 1;
1700
1701found_damage:
1702                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1703                dir.files[dir.nr].name = name;
1704                dir.files[dir.nr].changed = damage;
1705                changed += damage;
1706                dir.nr++;
1707        }
1708
1709        /* This can happen even with many files, if everything was renames */
1710        if (!changed)
1711                return;
1712
1713        /* Show all directories with more than x% of the changes */
1714        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1715        gather_dirstat(options, &dir, changed, "", 0);
1716}
1717
1718static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1719{
1720        int i;
1721        unsigned long changed;
1722        struct dirstat_dir dir;
1723
1724        if (data->nr == 0)
1725                return;
1726
1727        dir.files = NULL;
1728        dir.alloc = 0;
1729        dir.nr = 0;
1730        dir.permille = options->dirstat_permille;
1731        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1732
1733        changed = 0;
1734        for (i = 0; i < data->nr; i++) {
1735                struct diffstat_file *file = data->files[i];
1736                unsigned long damage = file->added + file->deleted;
1737                if (file->is_binary)
1738                        /*
1739                         * binary files counts bytes, not lines. Must find some
1740                         * way to normalize binary bytes vs. textual lines.
1741                         * The following heuristic assumes that there are 64
1742                         * bytes per "line".
1743                         * This is stupid and ugly, but very cheap...
1744                         */
1745                        damage = (damage + 63) / 64;
1746                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1747                dir.files[dir.nr].name = file->name;
1748                dir.files[dir.nr].changed = damage;
1749                changed += damage;
1750                dir.nr++;
1751        }
1752
1753        /* This can happen even with many files, if everything was renames */
1754        if (!changed)
1755                return;
1756
1757        /* Show all directories with more than x% of the changes */
1758        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1759        gather_dirstat(options, &dir, changed, "", 0);
1760}
1761
1762static void free_diffstat_info(struct diffstat_t *diffstat)
1763{
1764        int i;
1765        for (i = 0; i < diffstat->nr; i++) {
1766                struct diffstat_file *f = diffstat->files[i];
1767                if (f->name != f->print_name)
1768                        free(f->print_name);
1769                free(f->name);
1770                free(f->from_name);
1771                free(f);
1772        }
1773        free(diffstat->files);
1774}
1775
1776struct checkdiff_t {
1777        const char *filename;
1778        int lineno;
1779        int conflict_marker_size;
1780        struct diff_options *o;
1781        unsigned ws_rule;
1782        unsigned status;
1783};
1784
1785static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
1786{
1787        char firstchar;
1788        int cnt;
1789
1790        if (len < marker_size + 1)
1791                return 0;
1792        firstchar = line[0];
1793        switch (firstchar) {
1794        case '=': case '>': case '<': case '|':
1795                break;
1796        default:
1797                return 0;
1798        }
1799        for (cnt = 1; cnt < marker_size; cnt++)
1800                if (line[cnt] != firstchar)
1801                        return 0;
1802        /* line[1] thru line[marker_size-1] are same as firstchar */
1803        if (len < marker_size + 1 || !isspace(line[marker_size]))
1804                return 0;
1805        return 1;
1806}
1807
1808static void checkdiff_consume(void *priv, char *line, unsigned long len)
1809{
1810        struct checkdiff_t *data = priv;
1811        int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1812        int marker_size = data->conflict_marker_size;
1813        const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1814        const char *reset = diff_get_color(color_diff, DIFF_RESET);
1815        const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1816        char *err;
1817        char *line_prefix = "";
1818        struct strbuf *msgbuf;
1819
1820        assert(data->o);
1821        if (data->o->output_prefix) {
1822                msgbuf = data->o->output_prefix(data->o,
1823                        data->o->output_prefix_data);
1824                line_prefix = msgbuf->buf;
1825        }
1826
1827        if (line[0] == '+') {
1828                unsigned bad;
1829                data->lineno++;
1830                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
1831                        data->status |= 1;
1832                        fprintf(data->o->file,
1833                                "%s%s:%d: leftover conflict marker\n",
1834                                line_prefix, data->filename, data->lineno);
1835                }
1836                bad = ws_check(line + 1, len - 1, data->ws_rule);
1837                if (!bad)
1838                        return;
1839                data->status |= bad;
1840                err = whitespace_error_string(bad);
1841                fprintf(data->o->file, "%s%s:%d: %s.\n",
1842                        line_prefix, data->filename, data->lineno, err);
1843                free(err);
1844                emit_line(data->o, set, reset, line, 1);
1845                ws_check_emit(line + 1, len - 1, data->ws_rule,
1846                              data->o->file, set, reset, ws);
1847        } else if (line[0] == ' ') {
1848                data->lineno++;
1849        } else if (line[0] == '@') {
1850                char *plus = strchr(line, '+');
1851                if (plus)
1852                        data->lineno = strtol(plus, NULL, 10) - 1;
1853                else
1854                        die("invalid diff");
1855        }
1856}
1857
1858static unsigned char *deflate_it(char *data,
1859                                 unsigned long size,
1860                                 unsigned long *result_size)
1861{
1862        int bound;
1863        unsigned char *deflated;
1864        z_stream stream;
1865
1866        memset(&stream, 0, sizeof(stream));
1867        deflateInit(&stream, zlib_compression_level);
1868        bound = deflateBound(&stream, size);
1869        deflated = xmalloc(bound);
1870        stream.next_out = deflated;
1871        stream.avail_out = bound;
1872
1873        stream.next_in = (unsigned char *)data;
1874        stream.avail_in = size;
1875        while (deflate(&stream, Z_FINISH) == Z_OK)
1876                ; /* nothing */
1877        deflateEnd(&stream);
1878        *result_size = stream.total_out;
1879        return deflated;
1880}
1881
1882static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1883{
1884        void *cp;
1885        void *delta;
1886        void *deflated;
1887        void *data;
1888        unsigned long orig_size;
1889        unsigned long delta_size;
1890        unsigned long deflate_size;
1891        unsigned long data_size;
1892
1893        /* We could do deflated delta, or we could do just deflated two,
1894         * whichever is smaller.
1895         */
1896        delta = NULL;
1897        deflated = deflate_it(two->ptr, two->size, &deflate_size);
1898        if (one->size && two->size) {
1899                delta = diff_delta(one->ptr, one->size,
1900                                   two->ptr, two->size,
1901                                   &delta_size, deflate_size);
1902                if (delta) {
1903                        void *to_free = delta;
1904                        orig_size = delta_size;
1905                        delta = deflate_it(delta, delta_size, &delta_size);
1906                        free(to_free);
1907                }
1908        }
1909
1910        if (delta && delta_size < deflate_size) {
1911                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
1912                free(deflated);
1913                data = delta;
1914                data_size = delta_size;
1915        }
1916        else {
1917                fprintf(file, "%sliteral %lu\n", prefix, two->size);
1918                free(delta);
1919                data = deflated;
1920                data_size = deflate_size;
1921        }
1922
1923        /* emit data encoded in base85 */
1924        cp = data;
1925        while (data_size) {
1926                int bytes = (52 < data_size) ? 52 : data_size;
1927                char line[70];
1928                data_size -= bytes;
1929                if (bytes <= 26)
1930                        line[0] = bytes + 'A' - 1;
1931                else
1932                        line[0] = bytes - 26 + 'a' - 1;
1933                encode_85(line + 1, cp, bytes);
1934                cp = (char *) cp + bytes;
1935                fprintf(file, "%s", prefix);
1936                fputs(line, file);
1937                fputc('\n', file);
1938        }
1939        fprintf(file, "%s\n", prefix);
1940        free(data);
1941}
1942
1943static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1944{
1945        fprintf(file, "%sGIT binary patch\n", prefix);
1946        emit_binary_diff_body(file, one, two, prefix);
1947        emit_binary_diff_body(file, two, one, prefix);
1948}
1949
1950static void diff_filespec_load_driver(struct diff_filespec *one)
1951{
1952        /* Use already-loaded driver */
1953        if (one->driver)
1954                return;
1955
1956        if (S_ISREG(one->mode))
1957                one->driver = userdiff_find_by_path(one->path);
1958
1959        /* Fallback to default settings */
1960        if (!one->driver)
1961                one->driver = userdiff_find_by_name("default");
1962}
1963
1964int diff_filespec_is_binary(struct diff_filespec *one)
1965{
1966        if (one->is_binary == -1) {
1967                diff_filespec_load_driver(one);
1968                if (one->driver->binary != -1)
1969                        one->is_binary = one->driver->binary;
1970                else {
1971                        if (!one->data && DIFF_FILE_VALID(one))
1972                                diff_populate_filespec(one, 0);
1973                        if (one->data)
1974                                one->is_binary = buffer_is_binary(one->data,
1975                                                one->size);
1976                        if (one->is_binary == -1)
1977                                one->is_binary = 0;
1978                }
1979        }
1980        return one->is_binary;
1981}
1982
1983static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
1984{
1985        diff_filespec_load_driver(one);
1986        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
1987}
1988
1989static const char *userdiff_word_regex(struct diff_filespec *one)
1990{
1991        diff_filespec_load_driver(one);
1992        return one->driver->word_regex;
1993}
1994
1995void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
1996{
1997        if (!options->a_prefix)
1998                options->a_prefix = a;
1999        if (!options->b_prefix)
2000                options->b_prefix = b;
2001}
2002
2003struct userdiff_driver *get_textconv(struct diff_filespec *one)
2004{
2005        if (!DIFF_FILE_VALID(one))
2006                return NULL;
2007
2008        diff_filespec_load_driver(one);
2009        return userdiff_get_textconv(one->driver);
2010}
2011
2012static void builtin_diff(const char *name_a,
2013                         const char *name_b,
2014                         struct diff_filespec *one,
2015                         struct diff_filespec *two,
2016                         const char *xfrm_msg,
2017                         int must_show_header,
2018                         struct diff_options *o,
2019                         int complete_rewrite)
2020{
2021        mmfile_t mf1, mf2;
2022        const char *lbl[2];
2023        char *a_one, *b_two;
2024        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
2025        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2026        const char *a_prefix, *b_prefix;
2027        struct userdiff_driver *textconv_one = NULL;
2028        struct userdiff_driver *textconv_two = NULL;
2029        struct strbuf header = STRBUF_INIT;
2030        struct strbuf *msgbuf;
2031        char *line_prefix = "";
2032
2033        if (o->output_prefix) {
2034                msgbuf = o->output_prefix(o, o->output_prefix_data);
2035                line_prefix = msgbuf->buf;
2036        }
2037
2038        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2039                        (!one->mode || S_ISGITLINK(one->mode)) &&
2040                        (!two->mode || S_ISGITLINK(two->mode))) {
2041                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2042                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2043                show_submodule_summary(o->file, one ? one->path : two->path,
2044                                one->sha1, two->sha1, two->dirty_submodule,
2045                                del, add, reset);
2046                return;
2047        }
2048
2049        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2050                textconv_one = get_textconv(one);
2051                textconv_two = get_textconv(two);
2052        }
2053
2054        diff_set_mnemonic_prefix(o, "a/", "b/");
2055        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2056                a_prefix = o->b_prefix;
2057                b_prefix = o->a_prefix;
2058        } else {
2059                a_prefix = o->a_prefix;
2060                b_prefix = o->b_prefix;
2061        }
2062
2063        /* Never use a non-valid filename anywhere if at all possible */
2064        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2065        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2066
2067        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2068        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2069        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2070        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2071        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
2072        if (lbl[0][0] == '/') {
2073                /* /dev/null */
2074                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
2075                if (xfrm_msg)
2076                        strbuf_addstr(&header, xfrm_msg);
2077                must_show_header = 1;
2078        }
2079        else if (lbl[1][0] == '/') {
2080                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
2081                if (xfrm_msg)
2082                        strbuf_addstr(&header, xfrm_msg);
2083                must_show_header = 1;
2084        }
2085        else {
2086                if (one->mode != two->mode) {
2087                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
2088                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
2089                        must_show_header = 1;
2090                }
2091                if (xfrm_msg)
2092                        strbuf_addstr(&header, xfrm_msg);
2093
2094                /*
2095                 * we do not run diff between different kind
2096                 * of objects.
2097                 */
2098                if ((one->mode ^ two->mode) & S_IFMT)
2099                        goto free_ab_and_return;
2100                if (complete_rewrite &&
2101                    (textconv_one || !diff_filespec_is_binary(one)) &&
2102                    (textconv_two || !diff_filespec_is_binary(two))) {
2103                        fprintf(o->file, "%s", header.buf);
2104                        strbuf_reset(&header);
2105                        emit_rewrite_diff(name_a, name_b, one, two,
2106                                                textconv_one, textconv_two, o);
2107                        o->found_changes = 1;
2108                        goto free_ab_and_return;
2109                }
2110        }
2111
2112        if (o->irreversible_delete && lbl[1][0] == '/') {
2113                fprintf(o->file, "%s", header.buf);
2114                strbuf_reset(&header);
2115                goto free_ab_and_return;
2116        } else if (!DIFF_OPT_TST(o, TEXT) &&
2117            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2118              (!textconv_two && diff_filespec_is_binary(two)) )) {
2119                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2120                        die("unable to read files to diff");
2121                /* Quite common confusing case */
2122                if (mf1.size == mf2.size &&
2123                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2124                        if (must_show_header)
2125                                fprintf(o->file, "%s", header.buf);
2126                        goto free_ab_and_return;
2127                }
2128                fprintf(o->file, "%s", header.buf);
2129                strbuf_reset(&header);
2130                if (DIFF_OPT_TST(o, BINARY))
2131                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2132                else
2133                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2134                                line_prefix, lbl[0], lbl[1]);
2135                o->found_changes = 1;
2136        } else {
2137                /* Crazy xdl interfaces.. */
2138                const char *diffopts = getenv("GIT_DIFF_OPTS");
2139                xpparam_t xpp;
2140                xdemitconf_t xecfg;
2141                struct emit_callback ecbdata;
2142                const struct userdiff_funcname *pe;
2143
2144                if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
2145                        fprintf(o->file, "%s", header.buf);
2146                        strbuf_reset(&header);
2147                }
2148
2149                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2150                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2151
2152                pe = diff_funcname_pattern(one);
2153                if (!pe)
2154                        pe = diff_funcname_pattern(two);
2155
2156                memset(&xpp, 0, sizeof(xpp));
2157                memset(&xecfg, 0, sizeof(xecfg));
2158                memset(&ecbdata, 0, sizeof(ecbdata));
2159                ecbdata.label_path = lbl;
2160                ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
2161                ecbdata.found_changesp = &o->found_changes;
2162                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2163                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2164                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2165                ecbdata.opt = o;
2166                ecbdata.header = header.len ? &header : NULL;
2167                xpp.flags = o->xdl_opts;
2168                xecfg.ctxlen = o->context;
2169                xecfg.interhunkctxlen = o->interhunkcontext;
2170                xecfg.flags = XDL_EMIT_FUNCNAMES;
2171                if (pe)
2172                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2173                if (!diffopts)
2174                        ;
2175                else if (!prefixcmp(diffopts, "--unified="))
2176                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2177                else if (!prefixcmp(diffopts, "-u"))
2178                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2179                if (o->word_diff) {
2180                        int i;
2181
2182                        ecbdata.diff_words =
2183                                xcalloc(1, sizeof(struct diff_words_data));
2184                        ecbdata.diff_words->type = o->word_diff;
2185                        ecbdata.diff_words->opt = o;
2186                        if (!o->word_regex)
2187                                o->word_regex = userdiff_word_regex(one);
2188                        if (!o->word_regex)
2189                                o->word_regex = userdiff_word_regex(two);
2190                        if (!o->word_regex)
2191                                o->word_regex = diff_word_regex_cfg;
2192                        if (o->word_regex) {
2193                                ecbdata.diff_words->word_regex = (regex_t *)
2194                                        xmalloc(sizeof(regex_t));
2195                                if (regcomp(ecbdata.diff_words->word_regex,
2196                                                o->word_regex,
2197                                                REG_EXTENDED | REG_NEWLINE))
2198                                        die ("Invalid regular expression: %s",
2199                                                        o->word_regex);
2200                        }
2201                        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2202                                if (o->word_diff == diff_words_styles[i].type) {
2203                                        ecbdata.diff_words->style =
2204                                                &diff_words_styles[i];
2205                                        break;
2206                                }
2207                        }
2208                        if (DIFF_OPT_TST(o, COLOR_DIFF)) {
2209                                struct diff_words_style *st = ecbdata.diff_words->style;
2210                                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2211                                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2212                                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
2213                        }
2214                }
2215                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2216                              &xpp, &xecfg);
2217                if (o->word_diff)
2218                        free_diff_words_data(&ecbdata);
2219                if (textconv_one)
2220                        free(mf1.ptr);
2221                if (textconv_two)
2222                        free(mf2.ptr);
2223                xdiff_clear_find_func(&xecfg);
2224        }
2225
2226 free_ab_and_return:
2227        strbuf_release(&header);
2228        diff_free_filespec_data(one);
2229        diff_free_filespec_data(two);
2230        free(a_one);
2231        free(b_two);
2232        return;
2233}
2234
2235static void builtin_diffstat(const char *name_a, const char *name_b,
2236                             struct diff_filespec *one,
2237                             struct diff_filespec *two,
2238                             struct diffstat_t *diffstat,
2239                             struct diff_options *o,
2240                             int complete_rewrite)
2241{
2242        mmfile_t mf1, mf2;
2243        struct diffstat_file *data;
2244
2245        data = diffstat_add(diffstat, name_a, name_b);
2246
2247        if (!one || !two) {
2248                data->is_unmerged = 1;
2249                return;
2250        }
2251
2252        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2253                data->is_binary = 1;
2254                data->added = diff_filespec_size(two);
2255                data->deleted = diff_filespec_size(one);
2256        }
2257
2258        else if (complete_rewrite) {
2259                diff_populate_filespec(one, 0);
2260                diff_populate_filespec(two, 0);
2261                data->deleted = count_lines(one->data, one->size);
2262                data->added = count_lines(two->data, two->size);
2263        }
2264
2265        else {
2266                /* Crazy xdl interfaces.. */
2267                xpparam_t xpp;
2268                xdemitconf_t xecfg;
2269
2270                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2271                        die("unable to read files to diff");
2272
2273                memset(&xpp, 0, sizeof(xpp));
2274                memset(&xecfg, 0, sizeof(xecfg));
2275                xpp.flags = o->xdl_opts;
2276                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2277                              &xpp, &xecfg);
2278        }
2279
2280        diff_free_filespec_data(one);
2281        diff_free_filespec_data(two);
2282}
2283
2284static void builtin_checkdiff(const char *name_a, const char *name_b,
2285                              const char *attr_path,
2286                              struct diff_filespec *one,
2287                              struct diff_filespec *two,
2288                              struct diff_options *o)
2289{
2290        mmfile_t mf1, mf2;
2291        struct checkdiff_t data;
2292
2293        if (!two)
2294                return;
2295
2296        memset(&data, 0, sizeof(data));
2297        data.filename = name_b ? name_b : name_a;
2298        data.lineno = 0;
2299        data.o = o;
2300        data.ws_rule = whitespace_rule(attr_path);
2301        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2302
2303        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2304                die("unable to read files to diff");
2305
2306        /*
2307         * All the other codepaths check both sides, but not checking
2308         * the "old" side here is deliberate.  We are checking the newly
2309         * introduced changes, and as long as the "new" side is text, we
2310         * can and should check what it introduces.
2311         */
2312        if (diff_filespec_is_binary(two))
2313                goto free_and_return;
2314        else {
2315                /* Crazy xdl interfaces.. */
2316                xpparam_t xpp;
2317                xdemitconf_t xecfg;
2318
2319                memset(&xpp, 0, sizeof(xpp));
2320                memset(&xecfg, 0, sizeof(xecfg));
2321                xecfg.ctxlen = 1; /* at least one context line */
2322                xpp.flags = 0;
2323                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2324                              &xpp, &xecfg);
2325
2326                if (data.ws_rule & WS_BLANK_AT_EOF) {
2327                        struct emit_callback ecbdata;
2328                        int blank_at_eof;
2329
2330                        ecbdata.ws_rule = data.ws_rule;
2331                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2332                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2333
2334                        if (blank_at_eof) {
2335                                static char *err;
2336                                if (!err)
2337                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2338                                fprintf(o->file, "%s:%d: %s.\n",
2339                                        data.filename, blank_at_eof, err);
2340                                data.status = 1; /* report errors */
2341                        }
2342                }
2343        }
2344 free_and_return:
2345        diff_free_filespec_data(one);
2346        diff_free_filespec_data(two);
2347        if (data.status)
2348                DIFF_OPT_SET(o, CHECK_FAILED);
2349}
2350
2351struct diff_filespec *alloc_filespec(const char *path)
2352{
2353        int namelen = strlen(path);
2354        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2355
2356        memset(spec, 0, sizeof(*spec));
2357        spec->path = (char *)(spec + 1);
2358        memcpy(spec->path, path, namelen+1);
2359        spec->count = 1;
2360        spec->is_binary = -1;
2361        return spec;
2362}
2363
2364void free_filespec(struct diff_filespec *spec)
2365{
2366        if (!--spec->count) {
2367                diff_free_filespec_data(spec);
2368                free(spec);
2369        }
2370}
2371
2372void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2373                   unsigned short mode)
2374{
2375        if (mode) {
2376                spec->mode = canon_mode(mode);
2377                hashcpy(spec->sha1, sha1);
2378                spec->sha1_valid = !is_null_sha1(sha1);
2379        }
2380}
2381
2382/*
2383 * Given a name and sha1 pair, if the index tells us the file in
2384 * the work tree has that object contents, return true, so that
2385 * prepare_temp_file() does not have to inflate and extract.
2386 */
2387static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2388{
2389        struct cache_entry *ce;
2390        struct stat st;
2391        int pos, len;
2392
2393        /*
2394         * We do not read the cache ourselves here, because the
2395         * benchmark with my previous version that always reads cache
2396         * shows that it makes things worse for diff-tree comparing
2397         * two linux-2.6 kernel trees in an already checked out work
2398         * tree.  This is because most diff-tree comparisons deal with
2399         * only a small number of files, while reading the cache is
2400         * expensive for a large project, and its cost outweighs the
2401         * savings we get by not inflating the object to a temporary
2402         * file.  Practically, this code only helps when we are used
2403         * by diff-cache --cached, which does read the cache before
2404         * calling us.
2405         */
2406        if (!active_cache)
2407                return 0;
2408
2409        /* We want to avoid the working directory if our caller
2410         * doesn't need the data in a normal file, this system
2411         * is rather slow with its stat/open/mmap/close syscalls,
2412         * and the object is contained in a pack file.  The pack
2413         * is probably already open and will be faster to obtain
2414         * the data through than the working directory.  Loose
2415         * objects however would tend to be slower as they need
2416         * to be individually opened and inflated.
2417         */
2418        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2419                return 0;
2420
2421        len = strlen(name);
2422        pos = cache_name_pos(name, len);
2423        if (pos < 0)
2424                return 0;
2425        ce = active_cache[pos];
2426
2427        /*
2428         * This is not the sha1 we are looking for, or
2429         * unreusable because it is not a regular file.
2430         */
2431        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2432                return 0;
2433
2434        /*
2435         * If ce is marked as "assume unchanged", there is no
2436         * guarantee that work tree matches what we are looking for.
2437         */
2438        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2439                return 0;
2440
2441        /*
2442         * If ce matches the file in the work tree, we can reuse it.
2443         */
2444        if (ce_uptodate(ce) ||
2445            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2446                return 1;
2447
2448        return 0;
2449}
2450
2451static int populate_from_stdin(struct diff_filespec *s)
2452{
2453        struct strbuf buf = STRBUF_INIT;
2454        size_t size = 0;
2455
2456        if (strbuf_read(&buf, 0, 0) < 0)
2457                return error("error while reading from stdin %s",
2458                                     strerror(errno));
2459
2460        s->should_munmap = 0;
2461        s->data = strbuf_detach(&buf, &size);
2462        s->size = size;
2463        s->should_free = 1;
2464        return 0;
2465}
2466
2467static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2468{
2469        int len;
2470        char *data = xmalloc(100), *dirty = "";
2471
2472        /* Are we looking at the work tree? */
2473        if (s->dirty_submodule)
2474                dirty = "-dirty";
2475
2476        len = snprintf(data, 100,
2477                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2478        s->data = data;
2479        s->size = len;
2480        s->should_free = 1;
2481        if (size_only) {
2482                s->data = NULL;
2483                free(data);
2484        }
2485        return 0;
2486}
2487
2488/*
2489 * While doing rename detection and pickaxe operation, we may need to
2490 * grab the data for the blob (or file) for our own in-core comparison.
2491 * diff_filespec has data and size fields for this purpose.
2492 */
2493int diff_populate_filespec(struct diff_filespec *s, int size_only)
2494{
2495        int err = 0;
2496        if (!DIFF_FILE_VALID(s))
2497                die("internal error: asking to populate invalid file.");
2498        if (S_ISDIR(s->mode))
2499                return -1;
2500
2501        if (s->data)
2502                return 0;
2503
2504        if (size_only && 0 < s->size)
2505                return 0;
2506
2507        if (S_ISGITLINK(s->mode))
2508                return diff_populate_gitlink(s, size_only);
2509
2510        if (!s->sha1_valid ||
2511            reuse_worktree_file(s->path, s->sha1, 0)) {
2512                struct strbuf buf = STRBUF_INIT;
2513                struct stat st;
2514                int fd;
2515
2516                if (!strcmp(s->path, "-"))
2517                        return populate_from_stdin(s);
2518
2519                if (lstat(s->path, &st) < 0) {
2520                        if (errno == ENOENT) {
2521                        err_empty:
2522                                err = -1;
2523                        empty:
2524                                s->data = (char *)"";
2525                                s->size = 0;
2526                                return err;
2527                        }
2528                }
2529                s->size = xsize_t(st.st_size);
2530                if (!s->size)
2531                        goto empty;
2532                if (S_ISLNK(st.st_mode)) {
2533                        struct strbuf sb = STRBUF_INIT;
2534
2535                        if (strbuf_readlink(&sb, s->path, s->size))
2536                                goto err_empty;
2537                        s->size = sb.len;
2538                        s->data = strbuf_detach(&sb, NULL);
2539                        s->should_free = 1;
2540                        return 0;
2541                }
2542                if (size_only)
2543                        return 0;
2544                fd = open(s->path, O_RDONLY);
2545                if (fd < 0)
2546                        goto err_empty;
2547                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2548                close(fd);
2549                s->should_munmap = 1;
2550
2551                /*
2552                 * Convert from working tree format to canonical git format
2553                 */
2554                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2555                        size_t size = 0;
2556                        munmap(s->data, s->size);
2557                        s->should_munmap = 0;
2558                        s->data = strbuf_detach(&buf, &size);
2559                        s->size = size;
2560                        s->should_free = 1;
2561                }
2562        }
2563        else {
2564                enum object_type type;
2565                if (size_only) {
2566                        type = sha1_object_info(s->sha1, &s->size);
2567                        if (type < 0)
2568                                die("unable to read %s", sha1_to_hex(s->sha1));
2569                } else {
2570                        s->data = read_sha1_file(s->sha1, &type, &s->size);
2571                        if (!s->data)
2572                                die("unable to read %s", sha1_to_hex(s->sha1));
2573                        s->should_free = 1;
2574                }
2575        }
2576        return 0;
2577}
2578
2579void diff_free_filespec_blob(struct diff_filespec *s)
2580{
2581        if (s->should_free)
2582                free(s->data);
2583        else if (s->should_munmap)
2584                munmap(s->data, s->size);
2585
2586        if (s->should_free || s->should_munmap) {
2587                s->should_free = s->should_munmap = 0;
2588                s->data = NULL;
2589        }
2590}
2591
2592void diff_free_filespec_data(struct diff_filespec *s)
2593{
2594        diff_free_filespec_blob(s);
2595        free(s->cnt_data);
2596        s->cnt_data = NULL;
2597}
2598
2599static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2600                           void *blob,
2601                           unsigned long size,
2602                           const unsigned char *sha1,
2603                           int mode)
2604{
2605        int fd;
2606        struct strbuf buf = STRBUF_INIT;
2607        struct strbuf template = STRBUF_INIT;
2608        char *path_dup = xstrdup(path);
2609        const char *base = basename(path_dup);
2610
2611        /* Generate "XXXXXX_basename.ext" */
2612        strbuf_addstr(&template, "XXXXXX_");
2613        strbuf_addstr(&template, base);
2614
2615        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2616                        strlen(base) + 1);
2617        if (fd < 0)
2618                die_errno("unable to create temp-file");
2619        if (convert_to_working_tree(path,
2620                        (const char *)blob, (size_t)size, &buf)) {
2621                blob = buf.buf;
2622                size = buf.len;
2623        }
2624        if (write_in_full(fd, blob, size) != size)
2625                die_errno("unable to write temp-file");
2626        close(fd);
2627        temp->name = temp->tmp_path;
2628        strcpy(temp->hex, sha1_to_hex(sha1));
2629        temp->hex[40] = 0;
2630        sprintf(temp->mode, "%06o", mode);
2631        strbuf_release(&buf);
2632        strbuf_release(&template);
2633        free(path_dup);
2634}
2635
2636static struct diff_tempfile *prepare_temp_file(const char *name,
2637                struct diff_filespec *one)
2638{
2639        struct diff_tempfile *temp = claim_diff_tempfile();
2640
2641        if (!DIFF_FILE_VALID(one)) {
2642        not_a_valid_file:
2643                /* A '-' entry produces this for file-2, and
2644                 * a '+' entry produces this for file-1.
2645                 */
2646                temp->name = "/dev/null";
2647                strcpy(temp->hex, ".");
2648                strcpy(temp->mode, ".");
2649                return temp;
2650        }
2651
2652        if (!remove_tempfile_installed) {
2653                atexit(remove_tempfile);
2654                sigchain_push_common(remove_tempfile_on_signal);
2655                remove_tempfile_installed = 1;
2656        }
2657
2658        if (!one->sha1_valid ||
2659            reuse_worktree_file(name, one->sha1, 1)) {
2660                struct stat st;
2661                if (lstat(name, &st) < 0) {
2662                        if (errno == ENOENT)
2663                                goto not_a_valid_file;
2664                        die_errno("stat(%s)", name);
2665                }
2666                if (S_ISLNK(st.st_mode)) {
2667                        struct strbuf sb = STRBUF_INIT;
2668                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2669                                die_errno("readlink(%s)", name);
2670                        prep_temp_blob(name, temp, sb.buf, sb.len,
2671                                       (one->sha1_valid ?
2672                                        one->sha1 : null_sha1),
2673                                       (one->sha1_valid ?
2674                                        one->mode : S_IFLNK));
2675                        strbuf_release(&sb);
2676                }
2677                else {
2678                        /* we can borrow from the file in the work tree */
2679                        temp->name = name;
2680                        if (!one->sha1_valid)
2681                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2682                        else
2683                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2684                        /* Even though we may sometimes borrow the
2685                         * contents from the work tree, we always want
2686                         * one->mode.  mode is trustworthy even when
2687                         * !(one->sha1_valid), as long as
2688                         * DIFF_FILE_VALID(one).
2689                         */
2690                        sprintf(temp->mode, "%06o", one->mode);
2691                }
2692                return temp;
2693        }
2694        else {
2695                if (diff_populate_filespec(one, 0))
2696                        die("cannot read data blob for %s", one->path);
2697                prep_temp_blob(name, temp, one->data, one->size,
2698                               one->sha1, one->mode);
2699        }
2700        return temp;
2701}
2702
2703/* An external diff command takes:
2704 *
2705 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2706 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2707 *
2708 */
2709static void run_external_diff(const char *pgm,
2710                              const char *name,
2711                              const char *other,
2712                              struct diff_filespec *one,
2713                              struct diff_filespec *two,
2714                              const char *xfrm_msg,
2715                              int complete_rewrite)
2716{
2717        const char *spawn_arg[10];
2718        int retval;
2719        const char **arg = &spawn_arg[0];
2720
2721        if (one && two) {
2722                struct diff_tempfile *temp_one, *temp_two;
2723                const char *othername = (other ? other : name);
2724                temp_one = prepare_temp_file(name, one);
2725                temp_two = prepare_temp_file(othername, two);
2726                *arg++ = pgm;
2727                *arg++ = name;
2728                *arg++ = temp_one->name;
2729                *arg++ = temp_one->hex;
2730                *arg++ = temp_one->mode;
2731                *arg++ = temp_two->name;
2732                *arg++ = temp_two->hex;
2733                *arg++ = temp_two->mode;
2734                if (other) {
2735                        *arg++ = other;
2736                        *arg++ = xfrm_msg;
2737                }
2738        } else {
2739                *arg++ = pgm;
2740                *arg++ = name;
2741        }
2742        *arg = NULL;
2743        fflush(NULL);
2744        retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2745        remove_tempfile();
2746        if (retval) {
2747                fprintf(stderr, "external diff died, stopping at %s.\n", name);
2748                exit(1);
2749        }
2750}
2751
2752static int similarity_index(struct diff_filepair *p)
2753{
2754        return p->score * 100 / MAX_SCORE;
2755}
2756
2757static void fill_metainfo(struct strbuf *msg,
2758                          const char *name,
2759                          const char *other,
2760                          struct diff_filespec *one,
2761                          struct diff_filespec *two,
2762                          struct diff_options *o,
2763                          struct diff_filepair *p,
2764                          int *must_show_header,
2765                          int use_color)
2766{
2767        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2768        const char *reset = diff_get_color(use_color, DIFF_RESET);
2769        struct strbuf *msgbuf;
2770        char *line_prefix = "";
2771
2772        *must_show_header = 1;
2773        if (o->output_prefix) {
2774                msgbuf = o->output_prefix(o, o->output_prefix_data);
2775                line_prefix = msgbuf->buf;
2776        }
2777        strbuf_init(msg, PATH_MAX * 2 + 300);
2778        switch (p->status) {
2779        case DIFF_STATUS_COPIED:
2780                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2781                            line_prefix, set, similarity_index(p));
2782                strbuf_addf(msg, "%s\n%s%scopy from ",
2783                            reset,  line_prefix, set);
2784                quote_c_style(name, msg, NULL, 0);
2785                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2786                quote_c_style(other, msg, NULL, 0);
2787                strbuf_addf(msg, "%s\n", reset);
2788                break;
2789        case DIFF_STATUS_RENAMED:
2790                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2791                            line_prefix, set, similarity_index(p));
2792                strbuf_addf(msg, "%s\n%s%srename from ",
2793                            reset, line_prefix, set);
2794                quote_c_style(name, msg, NULL, 0);
2795                strbuf_addf(msg, "%s\n%s%srename to ",
2796                            reset, line_prefix, set);
2797                quote_c_style(other, msg, NULL, 0);
2798                strbuf_addf(msg, "%s\n", reset);
2799                break;
2800        case DIFF_STATUS_MODIFIED:
2801                if (p->score) {
2802                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2803                                    line_prefix,
2804                                    set, similarity_index(p), reset);
2805                        break;
2806                }
2807                /* fallthru */
2808        default:
2809                *must_show_header = 0;
2810        }
2811        if (one && two && hashcmp(one->sha1, two->sha1)) {
2812                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2813
2814                if (DIFF_OPT_TST(o, BINARY)) {
2815                        mmfile_t mf;
2816                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2817                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2818                                abbrev = 40;
2819                }
2820                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2821                            find_unique_abbrev(one->sha1, abbrev));
2822                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2823                if (one->mode == two->mode)
2824                        strbuf_addf(msg, " %06o", one->mode);
2825                strbuf_addf(msg, "%s\n", reset);
2826        }
2827}
2828
2829static void run_diff_cmd(const char *pgm,
2830                         const char *name,
2831                         const char *other,
2832                         const char *attr_path,
2833                         struct diff_filespec *one,
2834                         struct diff_filespec *two,
2835                         struct strbuf *msg,
2836                         struct diff_options *o,
2837                         struct diff_filepair *p)
2838{
2839        const char *xfrm_msg = NULL;
2840        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
2841        int must_show_header = 0;
2842
2843        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2844                pgm = NULL;
2845        else {
2846                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
2847                if (drv && drv->external)
2848                        pgm = drv->external;
2849        }
2850
2851        if (msg) {
2852                /*
2853                 * don't use colors when the header is intended for an
2854                 * external diff driver
2855                 */
2856                fill_metainfo(msg, name, other, one, two, o, p,
2857                              &must_show_header,
2858                              DIFF_OPT_TST(o, COLOR_DIFF) && !pgm);
2859                xfrm_msg = msg->len ? msg->buf : NULL;
2860        }
2861
2862        if (pgm) {
2863                run_external_diff(pgm, name, other, one, two, xfrm_msg,
2864                                  complete_rewrite);
2865                return;
2866        }
2867        if (one && two)
2868                builtin_diff(name, other ? other : name,
2869                             one, two, xfrm_msg, must_show_header,
2870                             o, complete_rewrite);
2871        else
2872                fprintf(o->file, "* Unmerged path %s\n", name);
2873}
2874
2875static void diff_fill_sha1_info(struct diff_filespec *one)
2876{
2877        if (DIFF_FILE_VALID(one)) {
2878                if (!one->sha1_valid) {
2879                        struct stat st;
2880                        if (!strcmp(one->path, "-")) {
2881                                hashcpy(one->sha1, null_sha1);
2882                                return;
2883                        }
2884                        if (lstat(one->path, &st) < 0)
2885                                die_errno("stat '%s'", one->path);
2886                        if (index_path(one->sha1, one->path, &st, 0))
2887                                die("cannot hash %s", one->path);
2888                }
2889        }
2890        else
2891                hashclr(one->sha1);
2892}
2893
2894static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2895{
2896        /* Strip the prefix but do not molest /dev/null and absolute paths */
2897        if (*namep && **namep != '/') {
2898                *namep += prefix_length;
2899                if (**namep == '/')
2900                        ++*namep;
2901        }
2902        if (*otherp && **otherp != '/') {
2903                *otherp += prefix_length;
2904                if (**otherp == '/')
2905                        ++*otherp;
2906        }
2907}
2908
2909static void run_diff(struct diff_filepair *p, struct diff_options *o)
2910{
2911        const char *pgm = external_diff();
2912        struct strbuf msg;
2913        struct diff_filespec *one = p->one;
2914        struct diff_filespec *two = p->two;
2915        const char *name;
2916        const char *other;
2917        const char *attr_path;
2918
2919        name  = p->one->path;
2920        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2921        attr_path = name;
2922        if (o->prefix_length)
2923                strip_prefix(o->prefix_length, &name, &other);
2924
2925        if (DIFF_PAIR_UNMERGED(p)) {
2926                run_diff_cmd(pgm, name, NULL, attr_path,
2927                             NULL, NULL, NULL, o, p);
2928                return;
2929        }
2930
2931        diff_fill_sha1_info(one);
2932        diff_fill_sha1_info(two);
2933
2934        if (!pgm &&
2935            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2936            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2937                /*
2938                 * a filepair that changes between file and symlink
2939                 * needs to be split into deletion and creation.
2940                 */
2941                struct diff_filespec *null = alloc_filespec(two->path);
2942                run_diff_cmd(NULL, name, other, attr_path,
2943                             one, null, &msg, o, p);
2944                free(null);
2945                strbuf_release(&msg);
2946
2947                null = alloc_filespec(one->path);
2948                run_diff_cmd(NULL, name, other, attr_path,
2949                             null, two, &msg, o, p);
2950                free(null);
2951        }
2952        else
2953                run_diff_cmd(pgm, name, other, attr_path,
2954                             one, two, &msg, o, p);
2955
2956        strbuf_release(&msg);
2957}
2958
2959static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2960                         struct diffstat_t *diffstat)
2961{
2962        const char *name;
2963        const char *other;
2964        int complete_rewrite = 0;
2965
2966        if (DIFF_PAIR_UNMERGED(p)) {
2967                /* unmerged */
2968                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2969                return;
2970        }
2971
2972        name = p->one->path;
2973        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2974
2975        if (o->prefix_length)
2976                strip_prefix(o->prefix_length, &name, &other);
2977
2978        diff_fill_sha1_info(p->one);
2979        diff_fill_sha1_info(p->two);
2980
2981        if (p->status == DIFF_STATUS_MODIFIED && p->score)
2982                complete_rewrite = 1;
2983        builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2984}
2985
2986static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2987{
2988        const char *name;
2989        const char *other;
2990        const char *attr_path;
2991
2992        if (DIFF_PAIR_UNMERGED(p)) {
2993                /* unmerged */
2994                return;
2995        }
2996
2997        name = p->one->path;
2998        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2999        attr_path = other ? other : name;
3000
3001        if (o->prefix_length)
3002                strip_prefix(o->prefix_length, &name, &other);
3003
3004        diff_fill_sha1_info(p->one);
3005        diff_fill_sha1_info(p->two);
3006
3007        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3008}
3009
3010void diff_setup(struct diff_options *options)
3011{
3012        memcpy(options, &default_diff_options, sizeof(*options));
3013
3014        options->file = stdout;
3015
3016        options->line_termination = '\n';
3017        options->break_opt = -1;
3018        options->rename_limit = -1;
3019        options->dirstat_permille = diff_dirstat_permille_default;
3020        options->context = 3;
3021
3022        options->change = diff_change;
3023        options->add_remove = diff_addremove;
3024        if (diff_use_color_default > 0)
3025                DIFF_OPT_SET(options, COLOR_DIFF);
3026        options->detect_rename = diff_detect_rename_default;
3027
3028        if (diff_no_prefix) {
3029                options->a_prefix = options->b_prefix = "";
3030        } else if (!diff_mnemonic_prefix) {
3031                options->a_prefix = "a/";
3032                options->b_prefix = "b/";
3033        }
3034}
3035
3036int diff_setup_done(struct diff_options *options)
3037{
3038        int count = 0;
3039
3040        if (options->output_format & DIFF_FORMAT_NAME)
3041                count++;
3042        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3043                count++;
3044        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3045                count++;
3046        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3047                count++;
3048        if (count > 1)
3049                die("--name-only, --name-status, --check and -s are mutually exclusive");
3050
3051        /*
3052         * Most of the time we can say "there are changes"
3053         * only by checking if there are changed paths, but
3054         * --ignore-whitespace* options force us to look
3055         * inside contents.
3056         */
3057
3058        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3059            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3060            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3061                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3062        else
3063                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3064
3065        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3066                options->detect_rename = DIFF_DETECT_COPY;
3067
3068        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3069                options->prefix = NULL;
3070        if (options->prefix)
3071                options->prefix_length = strlen(options->prefix);
3072        else
3073                options->prefix_length = 0;
3074
3075        if (options->output_format & (DIFF_FORMAT_NAME |
3076                                      DIFF_FORMAT_NAME_STATUS |
3077                                      DIFF_FORMAT_CHECKDIFF |
3078                                      DIFF_FORMAT_NO_OUTPUT))
3079                options->output_format &= ~(DIFF_FORMAT_RAW |
3080                                            DIFF_FORMAT_NUMSTAT |
3081                                            DIFF_FORMAT_DIFFSTAT |
3082                                            DIFF_FORMAT_SHORTSTAT |
3083                                            DIFF_FORMAT_DIRSTAT |
3084                                            DIFF_FORMAT_SUMMARY |
3085                                            DIFF_FORMAT_PATCH);
3086
3087        /*
3088         * These cases always need recursive; we do not drop caller-supplied
3089         * recursive bits for other formats here.
3090         */
3091        if (options->output_format & (DIFF_FORMAT_PATCH |
3092                                      DIFF_FORMAT_NUMSTAT |
3093                                      DIFF_FORMAT_DIFFSTAT |
3094                                      DIFF_FORMAT_SHORTSTAT |
3095                                      DIFF_FORMAT_DIRSTAT |
3096                                      DIFF_FORMAT_SUMMARY |
3097                                      DIFF_FORMAT_CHECKDIFF))
3098                DIFF_OPT_SET(options, RECURSIVE);
3099        /*
3100         * Also pickaxe would not work very well if you do not say recursive
3101         */
3102        if (options->pickaxe)
3103                DIFF_OPT_SET(options, RECURSIVE);
3104        /*
3105         * When patches are generated, submodules diffed against the work tree
3106         * must be checked for dirtiness too so it can be shown in the output
3107         */
3108        if (options->output_format & DIFF_FORMAT_PATCH)
3109                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3110
3111        if (options->detect_rename && options->rename_limit < 0)
3112                options->rename_limit = diff_rename_limit_default;
3113        if (options->setup & DIFF_SETUP_USE_CACHE) {
3114                if (!active_cache)
3115                        /* read-cache does not die even when it fails
3116                         * so it is safe for us to do this here.  Also
3117                         * it does not smudge active_cache or active_nr
3118                         * when it fails, so we do not have to worry about
3119                         * cleaning it up ourselves either.
3120                         */
3121                        read_cache();
3122        }
3123        if (options->abbrev <= 0 || 40 < options->abbrev)
3124                options->abbrev = 40; /* full */
3125
3126        /*
3127         * It does not make sense to show the first hit we happened
3128         * to have found.  It does not make sense not to return with
3129         * exit code in such a case either.
3130         */
3131        if (DIFF_OPT_TST(options, QUICK)) {
3132                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3133                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3134        }
3135
3136        return 0;
3137}
3138
3139static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3140{
3141        char c, *eq;
3142        int len;
3143
3144        if (*arg != '-')
3145                return 0;
3146        c = *++arg;
3147        if (!c)
3148                return 0;
3149        if (c == arg_short) {
3150                c = *++arg;
3151                if (!c)
3152                        return 1;
3153                if (val && isdigit(c)) {
3154                        char *end;
3155                        int n = strtoul(arg, &end, 10);
3156                        if (*end)
3157                                return 0;
3158                        *val = n;
3159                        return 1;
3160                }
3161                return 0;
3162        }
3163        if (c != '-')
3164                return 0;
3165        arg++;
3166        eq = strchr(arg, '=');
3167        if (eq)
3168                len = eq - arg;
3169        else
3170                len = strlen(arg);
3171        if (!len || strncmp(arg, arg_long, len))
3172                return 0;
3173        if (eq) {
3174                int n;
3175                char *end;
3176                if (!isdigit(*++eq))
3177                        return 0;
3178                n = strtoul(eq, &end, 10);
3179                if (*end)
3180                        return 0;
3181                *val = n;
3182        }
3183        return 1;
3184}
3185
3186static int diff_scoreopt_parse(const char *opt);
3187
3188static inline int short_opt(char opt, const char **argv,
3189                            const char **optarg)
3190{
3191        const char *arg = argv[0];
3192        if (arg[0] != '-' || arg[1] != opt)
3193                return 0;
3194        if (arg[2] != '\0') {
3195                *optarg = arg + 2;
3196                return 1;
3197        }
3198        if (!argv[1])
3199                die("Option '%c' requires a value", opt);
3200        *optarg = argv[1];
3201        return 2;
3202}
3203
3204int parse_long_opt(const char *opt, const char **argv,
3205                   const char **optarg)
3206{
3207        const char *arg = argv[0];
3208        if (arg[0] != '-' || arg[1] != '-')
3209                return 0;
3210        arg += strlen("--");
3211        if (prefixcmp(arg, opt))
3212                return 0;
3213        arg += strlen(opt);
3214        if (*arg == '=') { /* sticked form: --option=value */
3215                *optarg = arg + 1;
3216                return 1;
3217        }
3218        if (*arg != '\0')
3219                return 0;
3220        /* separate form: --option value */
3221        if (!argv[1])
3222                die("Option '--%s' requires a value", opt);
3223        *optarg = argv[1];
3224        return 2;
3225}
3226
3227static int stat_opt(struct diff_options *options, const char **av)
3228{
3229        const char *arg = av[0];
3230        char *end;
3231        int width = options->stat_width;
3232        int name_width = options->stat_name_width;
3233        int count = options->stat_count;
3234        int argcount = 1;
3235
3236        arg += strlen("--stat");
3237        end = (char *)arg;
3238
3239        switch (*arg) {
3240        case '-':
3241                if (!prefixcmp(arg, "-width")) {
3242                        arg += strlen("-width");
3243                        if (*arg == '=')
3244                                width = strtoul(arg + 1, &end, 10);
3245                        else if (!*arg && !av[1])
3246                                die("Option '--stat-width' requires a value");
3247                        else if (!*arg) {
3248                                width = strtoul(av[1], &end, 10);
3249                                argcount = 2;
3250                        }
3251                } else if (!prefixcmp(arg, "-name-width")) {
3252                        arg += strlen("-name-width");
3253                        if (*arg == '=')
3254                                name_width = strtoul(arg + 1, &end, 10);
3255                        else if (!*arg && !av[1])
3256                                die("Option '--stat-name-width' requires a value");
3257                        else if (!*arg) {
3258                                name_width = strtoul(av[1], &end, 10);
3259                                argcount = 2;
3260                        }
3261                } else if (!prefixcmp(arg, "-count")) {
3262                        arg += strlen("-count");
3263                        if (*arg == '=')
3264                                count = strtoul(arg + 1, &end, 10);
3265                        else if (!*arg && !av[1])
3266                                die("Option '--stat-count' requires a value");
3267                        else if (!*arg) {
3268                                count = strtoul(av[1], &end, 10);
3269                                argcount = 2;
3270                        }
3271                }
3272                break;
3273        case '=':
3274                width = strtoul(arg+1, &end, 10);
3275                if (*end == ',')
3276                        name_width = strtoul(end+1, &end, 10);
3277                if (*end == ',')
3278                        count = strtoul(end+1, &end, 10);
3279        }
3280
3281        /* Important! This checks all the error cases! */
3282        if (*end)
3283                return 0;
3284        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3285        options->stat_name_width = name_width;
3286        options->stat_width = width;
3287        options->stat_count = count;
3288        return argcount;
3289}
3290
3291static int parse_dirstat_opt(struct diff_options *options, const char *params)
3292{
3293        struct strbuf errmsg = STRBUF_INIT;
3294        if (parse_dirstat_params(options, params, &errmsg))
3295                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3296                    errmsg.buf);
3297        strbuf_release(&errmsg);
3298        /*
3299         * The caller knows a dirstat-related option is given from the command
3300         * line; allow it to say "return this_function();"
3301         */
3302        options->output_format |= DIFF_FORMAT_DIRSTAT;
3303        return 1;
3304}
3305
3306int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3307{
3308        const char *arg = av[0];
3309        const char *optarg;
3310        int argcount;
3311
3312        /* Output format options */
3313        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3314                options->output_format |= DIFF_FORMAT_PATCH;
3315        else if (opt_arg(arg, 'U', "unified", &options->context))
3316                options->output_format |= DIFF_FORMAT_PATCH;
3317        else if (!strcmp(arg, "--raw"))
3318                options->output_format |= DIFF_FORMAT_RAW;
3319        else if (!strcmp(arg, "--patch-with-raw"))
3320                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3321        else if (!strcmp(arg, "--numstat"))
3322                options->output_format |= DIFF_FORMAT_NUMSTAT;
3323        else if (!strcmp(arg, "--shortstat"))
3324                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3325        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3326                return parse_dirstat_opt(options, "");
3327        else if (!prefixcmp(arg, "-X"))
3328                return parse_dirstat_opt(options, arg + 2);
3329        else if (!prefixcmp(arg, "--dirstat="))
3330                return parse_dirstat_opt(options, arg + 10);
3331        else if (!strcmp(arg, "--cumulative"))
3332                return parse_dirstat_opt(options, "cumulative");
3333        else if (!strcmp(arg, "--dirstat-by-file"))
3334                return parse_dirstat_opt(options, "files");
3335        else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3336                parse_dirstat_opt(options, "files");
3337                return parse_dirstat_opt(options, arg + 18);
3338        }
3339        else if (!strcmp(arg, "--check"))
3340                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3341        else if (!strcmp(arg, "--summary"))
3342                options->output_format |= DIFF_FORMAT_SUMMARY;
3343        else if (!strcmp(arg, "--patch-with-stat"))
3344                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3345        else if (!strcmp(arg, "--name-only"))
3346                options->output_format |= DIFF_FORMAT_NAME;
3347        else if (!strcmp(arg, "--name-status"))
3348                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3349        else if (!strcmp(arg, "-s"))
3350                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3351        else if (!prefixcmp(arg, "--stat"))
3352                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3353                return stat_opt(options, av);
3354
3355        /* renames options */
3356        else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3357                 !strcmp(arg, "--break-rewrites")) {
3358                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3359                        return error("invalid argument to -B: %s", arg+2);
3360        }
3361        else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3362                 !strcmp(arg, "--find-renames")) {
3363                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3364                        return error("invalid argument to -M: %s", arg+2);
3365                options->detect_rename = DIFF_DETECT_RENAME;
3366        }
3367        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3368                options->irreversible_delete = 1;
3369        }
3370        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3371                 !strcmp(arg, "--find-copies")) {
3372                if (options->detect_rename == DIFF_DETECT_COPY)
3373                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3374                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3375                        return error("invalid argument to -C: %s", arg+2);
3376                options->detect_rename = DIFF_DETECT_COPY;
3377        }
3378        else if (!strcmp(arg, "--no-renames"))
3379                options->detect_rename = 0;
3380        else if (!strcmp(arg, "--relative"))
3381                DIFF_OPT_SET(options, RELATIVE_NAME);
3382        else if (!prefixcmp(arg, "--relative=")) {
3383                DIFF_OPT_SET(options, RELATIVE_NAME);
3384                options->prefix = arg + 11;
3385        }
3386
3387        /* xdiff options */
3388        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3389                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3390        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3391                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3392        else if (!strcmp(arg, "--ignore-space-at-eol"))
3393                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3394        else if (!strcmp(arg, "--patience"))
3395                DIFF_XDL_SET(options, PATIENCE_DIFF);
3396
3397        /* flags options */
3398        else if (!strcmp(arg, "--binary")) {
3399                options->output_format |= DIFF_FORMAT_PATCH;
3400                DIFF_OPT_SET(options, BINARY);
3401        }
3402        else if (!strcmp(arg, "--full-index"))
3403                DIFF_OPT_SET(options, FULL_INDEX);
3404        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3405                DIFF_OPT_SET(options, TEXT);
3406        else if (!strcmp(arg, "-R"))
3407                DIFF_OPT_SET(options, REVERSE_DIFF);
3408        else if (!strcmp(arg, "--find-copies-harder"))
3409                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3410        else if (!strcmp(arg, "--follow"))
3411                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3412        else if (!strcmp(arg, "--color"))
3413                DIFF_OPT_SET(options, COLOR_DIFF);
3414        else if (!prefixcmp(arg, "--color=")) {
3415                int value = git_config_colorbool(NULL, arg+8, -1);
3416                if (value == 0)
3417                        DIFF_OPT_CLR(options, COLOR_DIFF);
3418                else if (value > 0)
3419                        DIFF_OPT_SET(options, COLOR_DIFF);
3420                else
3421                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3422        }
3423        else if (!strcmp(arg, "--no-color"))
3424                DIFF_OPT_CLR(options, COLOR_DIFF);
3425        else if (!strcmp(arg, "--color-words")) {
3426                DIFF_OPT_SET(options, COLOR_DIFF);
3427                options->word_diff = DIFF_WORDS_COLOR;
3428        }
3429        else if (!prefixcmp(arg, "--color-words=")) {
3430                DIFF_OPT_SET(options, COLOR_DIFF);
3431                options->word_diff = DIFF_WORDS_COLOR;
3432                options->word_regex = arg + 14;
3433        }
3434        else if (!strcmp(arg, "--word-diff")) {
3435                if (options->word_diff == DIFF_WORDS_NONE)
3436                        options->word_diff = DIFF_WORDS_PLAIN;
3437        }
3438        else if (!prefixcmp(arg, "--word-diff=")) {
3439                const char *type = arg + 12;
3440                if (!strcmp(type, "plain"))
3441                        options->word_diff = DIFF_WORDS_PLAIN;
3442                else if (!strcmp(type, "color")) {
3443                        DIFF_OPT_SET(options, COLOR_DIFF);
3444                        options->word_diff = DIFF_WORDS_COLOR;
3445                }
3446                else if (!strcmp(type, "porcelain"))
3447                        options->word_diff = DIFF_WORDS_PORCELAIN;
3448                else if (!strcmp(type, "none"))
3449                        options->word_diff = DIFF_WORDS_NONE;
3450                else
3451                        die("bad --word-diff argument: %s", type);
3452        }
3453        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3454                if (options->word_diff == DIFF_WORDS_NONE)
3455                        options->word_diff = DIFF_WORDS_PLAIN;
3456                options->word_regex = optarg;
3457                return argcount;
3458        }
3459        else if (!strcmp(arg, "--exit-code"))
3460                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3461        else if (!strcmp(arg, "--quiet"))
3462                DIFF_OPT_SET(options, QUICK);
3463        else if (!strcmp(arg, "--ext-diff"))
3464                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3465        else if (!strcmp(arg, "--no-ext-diff"))
3466                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3467        else if (!strcmp(arg, "--textconv"))
3468                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3469        else if (!strcmp(arg, "--no-textconv"))
3470                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3471        else if (!strcmp(arg, "--ignore-submodules")) {
3472                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3473                handle_ignore_submodules_arg(options, "all");
3474        } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3475                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3476                handle_ignore_submodules_arg(options, arg + 20);
3477        } else if (!strcmp(arg, "--submodule"))
3478                DIFF_OPT_SET(options, SUBMODULE_LOG);
3479        else if (!prefixcmp(arg, "--submodule=")) {
3480                if (!strcmp(arg + 12, "log"))
3481                        DIFF_OPT_SET(options, SUBMODULE_LOG);
3482        }
3483
3484        /* misc options */
3485        else if (!strcmp(arg, "-z"))
3486                options->line_termination = 0;
3487        else if ((argcount = short_opt('l', av, &optarg))) {
3488                options->rename_limit = strtoul(optarg, NULL, 10);
3489                return argcount;
3490        }
3491        else if ((argcount = short_opt('S', av, &optarg))) {
3492                options->pickaxe = optarg;
3493                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3494                return argcount;
3495        } else if ((argcount = short_opt('G', av, &optarg))) {
3496                options->pickaxe = optarg;
3497                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3498                return argcount;
3499        }
3500        else if (!strcmp(arg, "--pickaxe-all"))
3501                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3502        else if (!strcmp(arg, "--pickaxe-regex"))
3503                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3504        else if ((argcount = short_opt('O', av, &optarg))) {
3505                options->orderfile = optarg;
3506                return argcount;
3507        }
3508        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3509                options->filter = optarg;
3510                return argcount;
3511        }
3512        else if (!strcmp(arg, "--abbrev"))
3513                options->abbrev = DEFAULT_ABBREV;
3514        else if (!prefixcmp(arg, "--abbrev=")) {
3515                options->abbrev = strtoul(arg + 9, NULL, 10);
3516                if (options->abbrev < MINIMUM_ABBREV)
3517                        options->abbrev = MINIMUM_ABBREV;
3518                else if (40 < options->abbrev)
3519                        options->abbrev = 40;
3520        }
3521        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3522                options->a_prefix = optarg;
3523                return argcount;
3524        }
3525        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3526                options->b_prefix = optarg;
3527                return argcount;
3528        }
3529        else if (!strcmp(arg, "--no-prefix"))
3530                options->a_prefix = options->b_prefix = "";
3531        else if (opt_arg(arg, '\0', "inter-hunk-context",
3532                         &options->interhunkcontext))
3533                ;
3534        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3535                options->file = fopen(optarg, "w");
3536                if (!options->file)
3537                        die_errno("Could not open '%s'", optarg);
3538                options->close_file = 1;
3539                return argcount;
3540        } else
3541                return 0;
3542        return 1;
3543}
3544
3545int parse_rename_score(const char **cp_p)
3546{
3547        unsigned long num, scale;
3548        int ch, dot;
3549        const char *cp = *cp_p;
3550
3551        num = 0;
3552        scale = 1;
3553        dot = 0;
3554        for (;;) {
3555                ch = *cp;
3556                if ( !dot && ch == '.' ) {
3557                        scale = 1;
3558                        dot = 1;
3559                } else if ( ch == '%' ) {
3560                        scale = dot ? scale*100 : 100;
3561                        cp++;   /* % is always at the end */
3562                        break;
3563                } else if ( ch >= '0' && ch <= '9' ) {
3564                        if ( scale < 100000 ) {
3565                                scale *= 10;
3566                                num = (num*10) + (ch-'0');
3567                        }
3568                } else {
3569                        break;
3570                }
3571                cp++;
3572        }
3573        *cp_p = cp;
3574
3575        /* user says num divided by scale and we say internally that
3576         * is MAX_SCORE * num / scale.
3577         */
3578        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3579}
3580
3581static int diff_scoreopt_parse(const char *opt)
3582{
3583        int opt1, opt2, cmd;
3584
3585        if (*opt++ != '-')
3586                return -1;
3587        cmd = *opt++;
3588        if (cmd == '-') {
3589                /* convert the long-form arguments into short-form versions */
3590                if (!prefixcmp(opt, "break-rewrites")) {
3591                        opt += strlen("break-rewrites");
3592                        if (*opt == 0 || *opt++ == '=')
3593                                cmd = 'B';
3594                } else if (!prefixcmp(opt, "find-copies")) {
3595                        opt += strlen("find-copies");
3596                        if (*opt == 0 || *opt++ == '=')
3597                                cmd = 'C';
3598                } else if (!prefixcmp(opt, "find-renames")) {
3599                        opt += strlen("find-renames");
3600                        if (*opt == 0 || *opt++ == '=')
3601                                cmd = 'M';
3602                }
3603        }
3604        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3605                return -1; /* that is not a -M, -C nor -B option */
3606
3607        opt1 = parse_rename_score(&opt);
3608        if (cmd != 'B')
3609                opt2 = 0;
3610        else {
3611                if (*opt == 0)
3612                        opt2 = 0;
3613                else if (*opt != '/')
3614                        return -1; /* we expect -B80/99 or -B80 */
3615                else {
3616                        opt++;
3617                        opt2 = parse_rename_score(&opt);
3618                }
3619        }
3620        if (*opt != 0)
3621                return -1;
3622        return opt1 | (opt2 << 16);
3623}
3624
3625struct diff_queue_struct diff_queued_diff;
3626
3627void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3628{
3629        if (queue->alloc <= queue->nr) {
3630                queue->alloc = alloc_nr(queue->alloc);
3631                queue->queue = xrealloc(queue->queue,
3632                                        sizeof(dp) * queue->alloc);
3633        }
3634        queue->queue[queue->nr++] = dp;
3635}
3636
3637struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3638                                 struct diff_filespec *one,
3639                                 struct diff_filespec *two)
3640{
3641        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3642        dp->one = one;
3643        dp->two = two;
3644        if (queue)
3645                diff_q(queue, dp);
3646        return dp;
3647}
3648
3649void diff_free_filepair(struct diff_filepair *p)
3650{
3651        free_filespec(p->one);
3652        free_filespec(p->two);
3653        free(p);
3654}
3655
3656/* This is different from find_unique_abbrev() in that
3657 * it stuffs the result with dots for alignment.
3658 */
3659const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3660{
3661        int abblen;
3662        const char *abbrev;
3663        if (len == 40)
3664                return sha1_to_hex(sha1);
3665
3666        abbrev = find_unique_abbrev(sha1, len);
3667        abblen = strlen(abbrev);
3668        if (abblen < 37) {
3669                static char hex[41];
3670                if (len < abblen && abblen <= len + 2)
3671                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3672                else
3673                        sprintf(hex, "%s...", abbrev);
3674                return hex;
3675        }
3676        return sha1_to_hex(sha1);
3677}
3678
3679static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3680{
3681        int line_termination = opt->line_termination;
3682        int inter_name_termination = line_termination ? '\t' : '\0';
3683        if (opt->output_prefix) {
3684                struct strbuf *msg = NULL;
3685                msg = opt->output_prefix(opt, opt->output_prefix_data);
3686                fprintf(opt->file, "%s", msg->buf);
3687        }
3688
3689        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3690                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3691                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
3692                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3693        }
3694        if (p->score) {
3695                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3696                        inter_name_termination);
3697        } else {
3698                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3699        }
3700
3701        if (p->status == DIFF_STATUS_COPIED ||
3702            p->status == DIFF_STATUS_RENAMED) {
3703                const char *name_a, *name_b;
3704                name_a = p->one->path;
3705                name_b = p->two->path;
3706                strip_prefix(opt->prefix_length, &name_a, &name_b);
3707                write_name_quoted(name_a, opt->file, inter_name_termination);
3708                write_name_quoted(name_b, opt->file, line_termination);
3709        } else {
3710                const char *name_a, *name_b;
3711                name_a = p->one->mode ? p->one->path : p->two->path;
3712                name_b = NULL;
3713                strip_prefix(opt->prefix_length, &name_a, &name_b);
3714                write_name_quoted(name_a, opt->file, line_termination);
3715        }
3716}
3717
3718int diff_unmodified_pair(struct diff_filepair *p)
3719{
3720        /* This function is written stricter than necessary to support
3721         * the currently implemented transformers, but the idea is to
3722         * let transformers to produce diff_filepairs any way they want,
3723         * and filter and clean them up here before producing the output.
3724         */
3725        struct diff_filespec *one = p->one, *two = p->two;
3726
3727        if (DIFF_PAIR_UNMERGED(p))
3728                return 0; /* unmerged is interesting */
3729
3730        /* deletion, addition, mode or type change
3731         * and rename are all interesting.
3732         */
3733        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3734            DIFF_PAIR_MODE_CHANGED(p) ||
3735            strcmp(one->path, two->path))
3736                return 0;
3737
3738        /* both are valid and point at the same path.  that is, we are
3739         * dealing with a change.
3740         */
3741        if (one->sha1_valid && two->sha1_valid &&
3742            !hashcmp(one->sha1, two->sha1) &&
3743            !one->dirty_submodule && !two->dirty_submodule)
3744                return 1; /* no change */
3745        if (!one->sha1_valid && !two->sha1_valid)
3746                return 1; /* both look at the same file on the filesystem. */
3747        return 0;
3748}
3749
3750static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3751{
3752        if (diff_unmodified_pair(p))
3753                return;
3754
3755        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3756            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3757                return; /* no tree diffs in patch format */
3758
3759        run_diff(p, o);
3760}
3761
3762static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3763                            struct diffstat_t *diffstat)
3764{
3765        if (diff_unmodified_pair(p))
3766                return;
3767
3768        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3769            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3770                return; /* no useful stat for tree diffs */
3771
3772        run_diffstat(p, o, diffstat);
3773}
3774
3775static void diff_flush_checkdiff(struct diff_filepair *p,
3776                struct diff_options *o)
3777{
3778        if (diff_unmodified_pair(p))
3779                return;
3780
3781        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3782            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3783                return; /* nothing to check in tree diffs */
3784
3785        run_checkdiff(p, o);
3786}
3787
3788int diff_queue_is_empty(void)
3789{
3790        struct diff_queue_struct *q = &diff_queued_diff;
3791        int i;
3792        for (i = 0; i < q->nr; i++)
3793                if (!diff_unmodified_pair(q->queue[i]))
3794                        return 0;
3795        return 1;
3796}
3797
3798#if DIFF_DEBUG
3799void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
3800{
3801        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
3802                x, one ? one : "",
3803                s->path,
3804                DIFF_FILE_VALID(s) ? "valid" : "invalid",
3805                s->mode,
3806                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
3807        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
3808                x, one ? one : "",
3809                s->size, s->xfrm_flags);
3810}
3811
3812void diff_debug_filepair(const struct diff_filepair *p, int i)
3813{
3814        diff_debug_filespec(p->one, i, "one");
3815        diff_debug_filespec(p->two, i, "two");
3816        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
3817                p->score, p->status ? p->status : '?',
3818                p->one->rename_used, p->broken_pair);
3819}
3820
3821void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
3822{
3823        int i;
3824        if (msg)
3825                fprintf(stderr, "%s\n", msg);
3826        fprintf(stderr, "q->nr = %d\n", q->nr);
3827        for (i = 0; i < q->nr; i++) {
3828                struct diff_filepair *p = q->queue[i];
3829                diff_debug_filepair(p, i);
3830        }
3831}
3832#endif
3833
3834static void diff_resolve_rename_copy(void)
3835{
3836        int i;
3837        struct diff_filepair *p;
3838        struct diff_queue_struct *q = &diff_queued_diff;
3839
3840        diff_debug_queue("resolve-rename-copy", q);
3841
3842        for (i = 0; i < q->nr; i++) {
3843                p = q->queue[i];
3844                p->status = 0; /* undecided */
3845                if (DIFF_PAIR_UNMERGED(p))
3846                        p->status = DIFF_STATUS_UNMERGED;
3847                else if (!DIFF_FILE_VALID(p->one))
3848                        p->status = DIFF_STATUS_ADDED;
3849                else if (!DIFF_FILE_VALID(p->two))
3850                        p->status = DIFF_STATUS_DELETED;
3851                else if (DIFF_PAIR_TYPE_CHANGED(p))
3852                        p->status = DIFF_STATUS_TYPE_CHANGED;
3853
3854                /* from this point on, we are dealing with a pair
3855                 * whose both sides are valid and of the same type, i.e.
3856                 * either in-place edit or rename/copy edit.
3857                 */
3858                else if (DIFF_PAIR_RENAME(p)) {
3859                        /*
3860                         * A rename might have re-connected a broken
3861                         * pair up, causing the pathnames to be the
3862                         * same again. If so, that's not a rename at
3863                         * all, just a modification..
3864                         *
3865                         * Otherwise, see if this source was used for
3866                         * multiple renames, in which case we decrement
3867                         * the count, and call it a copy.
3868                         */
3869                        if (!strcmp(p->one->path, p->two->path))
3870                                p->status = DIFF_STATUS_MODIFIED;
3871                        else if (--p->one->rename_used > 0)
3872                                p->status = DIFF_STATUS_COPIED;
3873                        else
3874                                p->status = DIFF_STATUS_RENAMED;
3875                }
3876                else if (hashcmp(p->one->sha1, p->two->sha1) ||
3877                         p->one->mode != p->two->mode ||
3878                         p->one->dirty_submodule ||
3879                         p->two->dirty_submodule ||
3880                         is_null_sha1(p->one->sha1))
3881                        p->status = DIFF_STATUS_MODIFIED;
3882                else {
3883                        /* This is a "no-change" entry and should not
3884                         * happen anymore, but prepare for broken callers.
3885                         */
3886                        error("feeding unmodified %s to diffcore",
3887                              p->one->path);
3888                        p->status = DIFF_STATUS_UNKNOWN;
3889                }
3890        }
3891        diff_debug_queue("resolve-rename-copy done", q);
3892}
3893
3894static int check_pair_status(struct diff_filepair *p)
3895{
3896        switch (p->status) {
3897        case DIFF_STATUS_UNKNOWN:
3898                return 0;
3899        case 0:
3900                die("internal error in diff-resolve-rename-copy");
3901        default:
3902                return 1;
3903        }
3904}
3905
3906static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
3907{
3908        int fmt = opt->output_format;
3909
3910        if (fmt & DIFF_FORMAT_CHECKDIFF)
3911                diff_flush_checkdiff(p, opt);
3912        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
3913                diff_flush_raw(p, opt);
3914        else if (fmt & DIFF_FORMAT_NAME) {
3915                const char *name_a, *name_b;
3916                name_a = p->two->path;
3917                name_b = NULL;
3918                strip_prefix(opt->prefix_length, &name_a, &name_b);
3919                write_name_quoted(name_a, opt->file, opt->line_termination);
3920        }
3921}
3922
3923static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
3924{
3925        if (fs->mode)
3926                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
3927        else
3928                fprintf(file, " %s ", newdelete);
3929        write_name_quoted(fs->path, file, '\n');
3930}
3931
3932
3933static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
3934                const char *line_prefix)
3935{
3936        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
3937                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
3938                        p->two->mode, show_name ? ' ' : '\n');
3939                if (show_name) {
3940                        write_name_quoted(p->two->path, file, '\n');
3941                }
3942        }
3943}
3944
3945static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
3946                        const char *line_prefix)
3947{
3948        char *names = pprint_rename(p->one->path, p->two->path);
3949
3950        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3951        free(names);
3952        show_mode_change(file, p, 0, line_prefix);
3953}
3954
3955static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
3956{
3957        FILE *file = opt->file;
3958        char *line_prefix = "";
3959
3960        if (opt->output_prefix) {
3961                struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
3962                line_prefix = buf->buf;
3963        }
3964
3965        switch(p->status) {
3966        case DIFF_STATUS_DELETED:
3967                fputs(line_prefix, file);
3968                show_file_mode_name(file, "delete", p->one);
3969                break;
3970        case DIFF_STATUS_ADDED:
3971                fputs(line_prefix, file);
3972                show_file_mode_name(file, "create", p->two);
3973                break;
3974        case DIFF_STATUS_COPIED:
3975                fputs(line_prefix, file);
3976                show_rename_copy(file, "copy", p, line_prefix);
3977                break;
3978        case DIFF_STATUS_RENAMED:
3979                fputs(line_prefix, file);
3980                show_rename_copy(file, "rename", p, line_prefix);
3981                break;
3982        default:
3983                if (p->score) {
3984                        fprintf(file, "%s rewrite ", line_prefix);
3985                        write_name_quoted(p->two->path, file, ' ');
3986                        fprintf(file, "(%d%%)\n", similarity_index(p));
3987                }
3988                show_mode_change(file, p, !p->score, line_prefix);
3989                break;
3990        }
3991}
3992
3993struct patch_id_t {
3994        git_SHA_CTX *ctx;
3995        int patchlen;
3996};
3997
3998static int remove_space(char *line, int len)
3999{
4000        int i;
4001        char *dst = line;
4002        unsigned char c;
4003
4004        for (i = 0; i < len; i++)
4005                if (!isspace((c = line[i])))
4006                        *dst++ = c;
4007
4008        return dst - line;
4009}
4010
4011static void patch_id_consume(void *priv, char *line, unsigned long len)
4012{
4013        struct patch_id_t *data = priv;
4014        int new_len;
4015
4016        /* Ignore line numbers when computing the SHA1 of the patch */
4017        if (!prefixcmp(line, "@@ -"))
4018                return;
4019
4020        new_len = remove_space(line, len);
4021
4022        git_SHA1_Update(data->ctx, line, new_len);
4023        data->patchlen += new_len;
4024}
4025
4026/* returns 0 upon success, and writes result into sha1 */
4027static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4028{
4029        struct diff_queue_struct *q = &diff_queued_diff;
4030        int i;
4031        git_SHA_CTX ctx;
4032        struct patch_id_t data;
4033        char buffer[PATH_MAX * 4 + 20];
4034
4035        git_SHA1_Init(&ctx);
4036        memset(&data, 0, sizeof(struct patch_id_t));
4037        data.ctx = &ctx;
4038
4039        for (i = 0; i < q->nr; i++) {
4040                xpparam_t xpp;
4041                xdemitconf_t xecfg;
4042                mmfile_t mf1, mf2;
4043                struct diff_filepair *p = q->queue[i];
4044                int len1, len2;
4045
4046                memset(&xpp, 0, sizeof(xpp));
4047                memset(&xecfg, 0, sizeof(xecfg));
4048                if (p->status == 0)
4049                        return error("internal diff status error");
4050                if (p->status == DIFF_STATUS_UNKNOWN)
4051                        continue;
4052                if (diff_unmodified_pair(p))
4053                        continue;
4054                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4055                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4056                        continue;
4057                if (DIFF_PAIR_UNMERGED(p))
4058                        continue;
4059
4060                diff_fill_sha1_info(p->one);
4061                diff_fill_sha1_info(p->two);
4062                if (fill_mmfile(&mf1, p->one) < 0 ||
4063                                fill_mmfile(&mf2, p->two) < 0)
4064                        return error("unable to read files to diff");
4065
4066                len1 = remove_space(p->one->path, strlen(p->one->path));
4067                len2 = remove_space(p->two->path, strlen(p->two->path));
4068                if (p->one->mode == 0)
4069                        len1 = snprintf(buffer, sizeof(buffer),
4070                                        "diff--gita/%.*sb/%.*s"
4071                                        "newfilemode%06o"
4072                                        "---/dev/null"
4073                                        "+++b/%.*s",
4074                                        len1, p->one->path,
4075                                        len2, p->two->path,
4076                                        p->two->mode,
4077                                        len2, p->two->path);
4078                else if (p->two->mode == 0)
4079                        len1 = snprintf(buffer, sizeof(buffer),
4080                                        "diff--gita/%.*sb/%.*s"
4081                                        "deletedfilemode%06o"
4082                                        "---a/%.*s"
4083                                        "+++/dev/null",
4084                                        len1, p->one->path,
4085                                        len2, p->two->path,
4086                                        p->one->mode,
4087                                        len1, p->one->path);
4088                else
4089                        len1 = snprintf(buffer, sizeof(buffer),
4090                                        "diff--gita/%.*sb/%.*s"
4091                                        "---a/%.*s"
4092                                        "+++b/%.*s",
4093                                        len1, p->one->path,
4094                                        len2, p->two->path,
4095                                        len1, p->one->path,
4096                                        len2, p->two->path);
4097                git_SHA1_Update(&ctx, buffer, len1);
4098
4099                if (diff_filespec_is_binary(p->one) ||
4100                    diff_filespec_is_binary(p->two)) {
4101                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4102                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4103                        continue;
4104                }
4105
4106                xpp.flags = 0;
4107                xecfg.ctxlen = 3;
4108                xecfg.flags = 0;
4109                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4110                              &xpp, &xecfg);
4111        }
4112
4113        git_SHA1_Final(sha1, &ctx);
4114        return 0;
4115}
4116
4117int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4118{
4119        struct diff_queue_struct *q = &diff_queued_diff;
4120        int i;
4121        int result = diff_get_patch_id(options, sha1);
4122
4123        for (i = 0; i < q->nr; i++)
4124                diff_free_filepair(q->queue[i]);
4125
4126        free(q->queue);
4127        DIFF_QUEUE_CLEAR(q);
4128
4129        return result;
4130}
4131
4132static int is_summary_empty(const struct diff_queue_struct *q)
4133{
4134        int i;
4135
4136        for (i = 0; i < q->nr; i++) {
4137                const struct diff_filepair *p = q->queue[i];
4138
4139                switch (p->status) {
4140                case DIFF_STATUS_DELETED:
4141                case DIFF_STATUS_ADDED:
4142                case DIFF_STATUS_COPIED:
4143                case DIFF_STATUS_RENAMED:
4144                        return 0;
4145                default:
4146                        if (p->score)
4147                                return 0;
4148                        if (p->one->mode && p->two->mode &&
4149                            p->one->mode != p->two->mode)
4150                                return 0;
4151                        break;
4152                }
4153        }
4154        return 1;
4155}
4156
4157static const char rename_limit_warning[] =
4158"inexact rename detection was skipped due to too many files.";
4159
4160static const char degrade_cc_to_c_warning[] =
4161"only found copies from modified paths due to too many files.";
4162
4163static const char rename_limit_advice[] =
4164"you may want to set your %s variable to at least "
4165"%d and retry the command.";
4166
4167void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4168{
4169        if (degraded_cc)
4170                warning(degrade_cc_to_c_warning);
4171        else if (needed)
4172                warning(rename_limit_warning);
4173        else
4174                return;
4175        if (0 < needed && needed < 32767)
4176                warning(rename_limit_advice, varname, needed);
4177}
4178
4179void diff_flush(struct diff_options *options)
4180{
4181        struct diff_queue_struct *q = &diff_queued_diff;
4182        int i, output_format = options->output_format;
4183        int separator = 0;
4184        int dirstat_by_line = 0;
4185
4186        /*
4187         * Order: raw, stat, summary, patch
4188         * or:    name/name-status/checkdiff (other bits clear)
4189         */
4190        if (!q->nr)
4191                goto free_queue;
4192
4193        if (output_format & (DIFF_FORMAT_RAW |
4194                             DIFF_FORMAT_NAME |
4195                             DIFF_FORMAT_NAME_STATUS |
4196                             DIFF_FORMAT_CHECKDIFF)) {
4197                for (i = 0; i < q->nr; i++) {
4198                        struct diff_filepair *p = q->queue[i];
4199                        if (check_pair_status(p))
4200                                flush_one_pair(p, options);
4201                }
4202                separator++;
4203        }
4204
4205        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4206                dirstat_by_line = 1;
4207
4208        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4209            dirstat_by_line) {
4210                struct diffstat_t diffstat;
4211
4212                memset(&diffstat, 0, sizeof(struct diffstat_t));
4213                for (i = 0; i < q->nr; i++) {
4214                        struct diff_filepair *p = q->queue[i];
4215                        if (check_pair_status(p))
4216                                diff_flush_stat(p, options, &diffstat);
4217                }
4218                if (output_format & DIFF_FORMAT_NUMSTAT)
4219                        show_numstat(&diffstat, options);
4220                if (output_format & DIFF_FORMAT_DIFFSTAT)
4221                        show_stats(&diffstat, options);
4222                if (output_format & DIFF_FORMAT_SHORTSTAT)
4223                        show_shortstats(&diffstat, options);
4224                if (output_format & DIFF_FORMAT_DIRSTAT)
4225                        show_dirstat_by_line(&diffstat, options);
4226                free_diffstat_info(&diffstat);
4227                separator++;
4228        }
4229        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4230                show_dirstat(options);
4231
4232        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4233                for (i = 0; i < q->nr; i++) {
4234                        diff_summary(options, q->queue[i]);
4235                }
4236                separator++;
4237        }
4238
4239        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4240            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4241            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4242                /*
4243                 * run diff_flush_patch for the exit status. setting
4244                 * options->file to /dev/null should be safe, becaue we
4245                 * aren't supposed to produce any output anyway.
4246                 */
4247                if (options->close_file)
4248                        fclose(options->file);
4249                options->file = fopen("/dev/null", "w");
4250                if (!options->file)
4251                        die_errno("Could not open /dev/null");
4252                options->close_file = 1;
4253                for (i = 0; i < q->nr; i++) {
4254                        struct diff_filepair *p = q->queue[i];
4255                        if (check_pair_status(p))
4256                                diff_flush_patch(p, options);
4257                        if (options->found_changes)
4258                                break;
4259                }
4260        }
4261
4262        if (output_format & DIFF_FORMAT_PATCH) {
4263                if (separator) {
4264                        putc(options->line_termination, options->file);
4265                        if (options->stat_sep) {
4266                                /* attach patch instead of inline */
4267                                fputs(options->stat_sep, options->file);
4268                        }
4269                }
4270
4271                for (i = 0; i < q->nr; i++) {
4272                        struct diff_filepair *p = q->queue[i];
4273                        if (check_pair_status(p))
4274                                diff_flush_patch(p, options);
4275                }
4276        }
4277
4278        if (output_format & DIFF_FORMAT_CALLBACK)
4279                options->format_callback(q, options, options->format_callback_data);
4280
4281        for (i = 0; i < q->nr; i++)
4282                diff_free_filepair(q->queue[i]);
4283free_queue:
4284        free(q->queue);
4285        DIFF_QUEUE_CLEAR(q);
4286        if (options->close_file)
4287                fclose(options->file);
4288
4289        /*
4290         * Report the content-level differences with HAS_CHANGES;
4291         * diff_addremove/diff_change does not set the bit when
4292         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4293         */
4294        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4295                if (options->found_changes)
4296                        DIFF_OPT_SET(options, HAS_CHANGES);
4297                else
4298                        DIFF_OPT_CLR(options, HAS_CHANGES);
4299        }
4300}
4301
4302static void diffcore_apply_filter(const char *filter)
4303{
4304        int i;
4305        struct diff_queue_struct *q = &diff_queued_diff;
4306        struct diff_queue_struct outq;
4307        DIFF_QUEUE_CLEAR(&outq);
4308
4309        if (!filter)
4310                return;
4311
4312        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4313                int found;
4314                for (i = found = 0; !found && i < q->nr; i++) {
4315                        struct diff_filepair *p = q->queue[i];
4316                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4317                             ((p->score &&
4318                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4319                              (!p->score &&
4320                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4321                            ((p->status != DIFF_STATUS_MODIFIED) &&
4322                             strchr(filter, p->status)))
4323                                found++;
4324                }
4325                if (found)
4326                        return;
4327
4328                /* otherwise we will clear the whole queue
4329                 * by copying the empty outq at the end of this
4330                 * function, but first clear the current entries
4331                 * in the queue.
4332                 */
4333                for (i = 0; i < q->nr; i++)
4334                        diff_free_filepair(q->queue[i]);
4335        }
4336        else {
4337                /* Only the matching ones */
4338                for (i = 0; i < q->nr; i++) {
4339                        struct diff_filepair *p = q->queue[i];
4340
4341                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4342                             ((p->score &&
4343                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4344                              (!p->score &&
4345                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4346                            ((p->status != DIFF_STATUS_MODIFIED) &&
4347                             strchr(filter, p->status)))
4348                                diff_q(&outq, p);
4349                        else
4350                                diff_free_filepair(p);
4351                }
4352        }
4353        free(q->queue);
4354        *q = outq;
4355}
4356
4357/* Check whether two filespecs with the same mode and size are identical */
4358static int diff_filespec_is_identical(struct diff_filespec *one,
4359                                      struct diff_filespec *two)
4360{
4361        if (S_ISGITLINK(one->mode))
4362                return 0;
4363        if (diff_populate_filespec(one, 0))
4364                return 0;
4365        if (diff_populate_filespec(two, 0))
4366                return 0;
4367        return !memcmp(one->data, two->data, one->size);
4368}
4369
4370static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4371{
4372        int i;
4373        struct diff_queue_struct *q = &diff_queued_diff;
4374        struct diff_queue_struct outq;
4375        DIFF_QUEUE_CLEAR(&outq);
4376
4377        for (i = 0; i < q->nr; i++) {
4378                struct diff_filepair *p = q->queue[i];
4379
4380                /*
4381                 * 1. Entries that come from stat info dirtiness
4382                 *    always have both sides (iow, not create/delete),
4383                 *    one side of the object name is unknown, with
4384                 *    the same mode and size.  Keep the ones that
4385                 *    do not match these criteria.  They have real
4386                 *    differences.
4387                 *
4388                 * 2. At this point, the file is known to be modified,
4389                 *    with the same mode and size, and the object
4390                 *    name of one side is unknown.  Need to inspect
4391                 *    the identical contents.
4392                 */
4393                if (!DIFF_FILE_VALID(p->one) || /* (1) */
4394                    !DIFF_FILE_VALID(p->two) ||
4395                    (p->one->sha1_valid && p->two->sha1_valid) ||
4396                    (p->one->mode != p->two->mode) ||
4397                    diff_populate_filespec(p->one, 1) ||
4398                    diff_populate_filespec(p->two, 1) ||
4399                    (p->one->size != p->two->size) ||
4400                    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4401                        diff_q(&outq, p);
4402                else {
4403                        /*
4404                         * The caller can subtract 1 from skip_stat_unmatch
4405                         * to determine how many paths were dirty only
4406                         * due to stat info mismatch.
4407                         */
4408                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4409                                diffopt->skip_stat_unmatch++;
4410                        diff_free_filepair(p);
4411                }
4412        }
4413        free(q->queue);
4414        *q = outq;
4415}
4416
4417static int diffnamecmp(const void *a_, const void *b_)
4418{
4419        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4420        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4421        const char *name_a, *name_b;
4422
4423        name_a = a->one ? a->one->path : a->two->path;
4424        name_b = b->one ? b->one->path : b->two->path;
4425        return strcmp(name_a, name_b);
4426}
4427
4428void diffcore_fix_diff_index(struct diff_options *options)
4429{
4430        struct diff_queue_struct *q = &diff_queued_diff;
4431        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4432}
4433
4434void diffcore_std(struct diff_options *options)
4435{
4436        if (options->skip_stat_unmatch)
4437                diffcore_skip_stat_unmatch(options);
4438        if (!options->found_follow) {
4439                /* See try_to_follow_renames() in tree-diff.c */
4440                if (options->break_opt != -1)
4441                        diffcore_break(options->break_opt);
4442                if (options->detect_rename)
4443                        diffcore_rename(options);
4444                if (options->break_opt != -1)
4445                        diffcore_merge_broken();
4446        }
4447        if (options->pickaxe)
4448                diffcore_pickaxe(options);
4449        if (options->orderfile)
4450                diffcore_order(options->orderfile);
4451        if (!options->found_follow)
4452                /* See try_to_follow_renames() in tree-diff.c */
4453                diff_resolve_rename_copy();
4454        diffcore_apply_filter(options->filter);
4455
4456        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4457                DIFF_OPT_SET(options, HAS_CHANGES);
4458        else
4459                DIFF_OPT_CLR(options, HAS_CHANGES);
4460
4461        options->found_follow = 0;
4462}
4463
4464int diff_result_code(struct diff_options *opt, int status)
4465{
4466        int result = 0;
4467
4468        diff_warn_rename_limit("diff.renamelimit",
4469                               opt->needed_rename_limit,
4470                               opt->degraded_cc_to_c);
4471        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4472            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4473                return status;
4474        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4475            DIFF_OPT_TST(opt, HAS_CHANGES))
4476                result |= 01;
4477        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4478            DIFF_OPT_TST(opt, CHECK_FAILED))
4479                result |= 02;
4480        return result;
4481}
4482
4483int diff_can_quit_early(struct diff_options *opt)
4484{
4485        return (DIFF_OPT_TST(opt, QUICK) &&
4486                !opt->filter &&
4487                DIFF_OPT_TST(opt, HAS_CHANGES));
4488}
4489
4490/*
4491 * Shall changes to this submodule be ignored?
4492 *
4493 * Submodule changes can be configured to be ignored separately for each path,
4494 * but that configuration can be overridden from the command line.
4495 */
4496static int is_submodule_ignored(const char *path, struct diff_options *options)
4497{
4498        int ignored = 0;
4499        unsigned orig_flags = options->flags;
4500        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4501                set_diffopt_flags_from_submodule_config(options, path);
4502        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4503                ignored = 1;
4504        options->flags = orig_flags;
4505        return ignored;
4506}
4507
4508void diff_addremove(struct diff_options *options,
4509                    int addremove, unsigned mode,
4510                    const unsigned char *sha1,
4511                    const char *concatpath, unsigned dirty_submodule)
4512{
4513        struct diff_filespec *one, *two;
4514
4515        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4516                return;
4517
4518        /* This may look odd, but it is a preparation for
4519         * feeding "there are unchanged files which should
4520         * not produce diffs, but when you are doing copy
4521         * detection you would need them, so here they are"
4522         * entries to the diff-core.  They will be prefixed
4523         * with something like '=' or '*' (I haven't decided
4524         * which but should not make any difference).
4525         * Feeding the same new and old to diff_change()
4526         * also has the same effect.
4527         * Before the final output happens, they are pruned after
4528         * merged into rename/copy pairs as appropriate.
4529         */
4530        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4531                addremove = (addremove == '+' ? '-' :
4532                             addremove == '-' ? '+' : addremove);
4533
4534        if (options->prefix &&
4535            strncmp(concatpath, options->prefix, options->prefix_length))
4536                return;
4537
4538        one = alloc_filespec(concatpath);
4539        two = alloc_filespec(concatpath);
4540
4541        if (addremove != '+')
4542                fill_filespec(one, sha1, mode);
4543        if (addremove != '-') {
4544                fill_filespec(two, sha1, mode);
4545                two->dirty_submodule = dirty_submodule;
4546        }
4547
4548        diff_queue(&diff_queued_diff, one, two);
4549        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4550                DIFF_OPT_SET(options, HAS_CHANGES);
4551}
4552
4553void diff_change(struct diff_options *options,
4554                 unsigned old_mode, unsigned new_mode,
4555                 const unsigned char *old_sha1,
4556                 const unsigned char *new_sha1,
4557                 const char *concatpath,
4558                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4559{
4560        struct diff_filespec *one, *two;
4561
4562        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4563            is_submodule_ignored(concatpath, options))
4564                return;
4565
4566        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4567                unsigned tmp;
4568                const unsigned char *tmp_c;
4569                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4570                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4571                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4572                        new_dirty_submodule = tmp;
4573        }
4574
4575        if (options->prefix &&
4576            strncmp(concatpath, options->prefix, options->prefix_length))
4577                return;
4578
4579        one = alloc_filespec(concatpath);
4580        two = alloc_filespec(concatpath);
4581        fill_filespec(one, old_sha1, old_mode);
4582        fill_filespec(two, new_sha1, new_mode);
4583        one->dirty_submodule = old_dirty_submodule;
4584        two->dirty_submodule = new_dirty_submodule;
4585
4586        diff_queue(&diff_queued_diff, one, two);
4587        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4588                DIFF_OPT_SET(options, HAS_CHANGES);
4589}
4590
4591struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4592{
4593        struct diff_filepair *pair;
4594        struct diff_filespec *one, *two;
4595
4596        if (options->prefix &&
4597            strncmp(path, options->prefix, options->prefix_length))
4598                return NULL;
4599
4600        one = alloc_filespec(path);
4601        two = alloc_filespec(path);
4602        pair = diff_queue(&diff_queued_diff, one, two);
4603        pair->is_unmerged = 1;
4604        return pair;
4605}
4606
4607static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4608                size_t *outsize)
4609{
4610        struct diff_tempfile *temp;
4611        const char *argv[3];
4612        const char **arg = argv;
4613        struct child_process child;
4614        struct strbuf buf = STRBUF_INIT;
4615        int err = 0;
4616
4617        temp = prepare_temp_file(spec->path, spec);
4618        *arg++ = pgm;
4619        *arg++ = temp->name;
4620        *arg = NULL;
4621
4622        memset(&child, 0, sizeof(child));
4623        child.use_shell = 1;
4624        child.argv = argv;
4625        child.out = -1;
4626        if (start_command(&child)) {
4627                remove_tempfile();
4628                return NULL;
4629        }
4630
4631        if (strbuf_read(&buf, child.out, 0) < 0)
4632                err = error("error reading from textconv command '%s'", pgm);
4633        close(child.out);
4634
4635        if (finish_command(&child) || err) {
4636                strbuf_release(&buf);
4637                remove_tempfile();
4638                return NULL;
4639        }
4640        remove_tempfile();
4641
4642        return strbuf_detach(&buf, outsize);
4643}
4644
4645size_t fill_textconv(struct userdiff_driver *driver,
4646                     struct diff_filespec *df,
4647                     char **outbuf)
4648{
4649        size_t size;
4650
4651        if (!driver || !driver->textconv) {
4652                if (!DIFF_FILE_VALID(df)) {
4653                        *outbuf = "";
4654                        return 0;
4655                }
4656                if (diff_populate_filespec(df, 0))
4657                        die("unable to read files to diff");
4658                *outbuf = df->data;
4659                return df->size;
4660        }
4661
4662        if (driver->textconv_cache && df->sha1_valid) {
4663                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4664                                          &size);
4665                if (*outbuf)
4666                        return size;
4667        }
4668
4669        *outbuf = run_textconv(driver->textconv, df, &size);
4670        if (!*outbuf)
4671                die("unable to read files to diff");
4672
4673        if (driver->textconv_cache && df->sha1_valid) {
4674                /* ignore errors, as we might be in a readonly repository */
4675                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4676                                size);
4677                /*
4678                 * we could save up changes and flush them all at the end,
4679                 * but we would need an extra call after all diffing is done.
4680                 * Since generating a cache entry is the slow path anyway,
4681                 * this extra overhead probably isn't a big deal.
4682                 */
4683                notes_cache_write(driver->textconv_cache);
4684        }
4685
4686        return size;
4687}