diff.con commit t5551: do not assume the "matching" push is the default (bd7ac59)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18#include "string-list.h"
  19
  20#ifdef NO_FAST_WORKING_DIRECTORY
  21#define FAST_WORKING_DIRECTORY 0
  22#else
  23#define FAST_WORKING_DIRECTORY 1
  24#endif
  25
  26static int diff_detect_rename_default;
  27static int diff_rename_limit_default = 400;
  28static int diff_suppress_blank_empty;
  29static int diff_use_color_default = -1;
  30static int diff_context_default = 3;
  31static const char *diff_word_regex_cfg;
  32static const char *external_diff_cmd_cfg;
  33int diff_auto_refresh_index = 1;
  34static int diff_mnemonic_prefix;
  35static int diff_no_prefix;
  36static int diff_stat_graph_width;
  37static int diff_dirstat_permille_default = 30;
  38static struct diff_options default_diff_options;
  39
  40static char diff_colors[][COLOR_MAXLEN] = {
  41        GIT_COLOR_RESET,
  42        GIT_COLOR_NORMAL,       /* PLAIN */
  43        GIT_COLOR_BOLD,         /* METAINFO */
  44        GIT_COLOR_CYAN,         /* FRAGINFO */
  45        GIT_COLOR_RED,          /* OLD */
  46        GIT_COLOR_GREEN,        /* NEW */
  47        GIT_COLOR_YELLOW,       /* COMMIT */
  48        GIT_COLOR_BG_RED,       /* WHITESPACE */
  49        GIT_COLOR_NORMAL,       /* FUNCINFO */
  50};
  51
  52static int parse_diff_color_slot(const char *var, int ofs)
  53{
  54        if (!strcasecmp(var+ofs, "plain"))
  55                return DIFF_PLAIN;
  56        if (!strcasecmp(var+ofs, "meta"))
  57                return DIFF_METAINFO;
  58        if (!strcasecmp(var+ofs, "frag"))
  59                return DIFF_FRAGINFO;
  60        if (!strcasecmp(var+ofs, "old"))
  61                return DIFF_FILE_OLD;
  62        if (!strcasecmp(var+ofs, "new"))
  63                return DIFF_FILE_NEW;
  64        if (!strcasecmp(var+ofs, "commit"))
  65                return DIFF_COMMIT;
  66        if (!strcasecmp(var+ofs, "whitespace"))
  67                return DIFF_WHITESPACE;
  68        if (!strcasecmp(var+ofs, "func"))
  69                return DIFF_FUNCINFO;
  70        return -1;
  71}
  72
  73static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  74                                struct strbuf *errmsg)
  75{
  76        char *params_copy = xstrdup(params_string);
  77        struct string_list params = STRING_LIST_INIT_NODUP;
  78        int ret = 0;
  79        int i;
  80
  81        if (*params_copy)
  82                string_list_split_in_place(&params, params_copy, ',', -1);
  83        for (i = 0; i < params.nr; i++) {
  84                const char *p = params.items[i].string;
  85                if (!strcmp(p, "changes")) {
  86                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  87                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  88                } else if (!strcmp(p, "lines")) {
  89                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  90                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  91                } else if (!strcmp(p, "files")) {
  92                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  93                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  94                } else if (!strcmp(p, "noncumulative")) {
  95                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  96                } else if (!strcmp(p, "cumulative")) {
  97                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  98                } else if (isdigit(*p)) {
  99                        char *end;
 100                        int permille = strtoul(p, &end, 10) * 10;
 101                        if (*end == '.' && isdigit(*++end)) {
 102                                /* only use first digit */
 103                                permille += *end - '0';
 104                                /* .. and ignore any further digits */
 105                                while (isdigit(*++end))
 106                                        ; /* nothing */
 107                        }
 108                        if (!*end)
 109                                options->dirstat_permille = permille;
 110                        else {
 111                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 112                                            p);
 113                                ret++;
 114                        }
 115                } else {
 116                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 117                        ret++;
 118                }
 119
 120        }
 121        string_list_clear(&params, 0);
 122        free(params_copy);
 123        return ret;
 124}
 125
 126static int parse_submodule_params(struct diff_options *options, const char *value)
 127{
 128        if (!strcmp(value, "log"))
 129                DIFF_OPT_SET(options, SUBMODULE_LOG);
 130        else if (!strcmp(value, "short"))
 131                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 132        else
 133                return -1;
 134        return 0;
 135}
 136
 137static int git_config_rename(const char *var, const char *value)
 138{
 139        if (!value)
 140                return DIFF_DETECT_RENAME;
 141        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 142                return  DIFF_DETECT_COPY;
 143        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 144}
 145
 146/*
 147 * These are to give UI layer defaults.
 148 * The core-level commands such as git-diff-files should
 149 * never be affected by the setting of diff.renames
 150 * the user happens to have in the configuration file.
 151 */
 152int git_diff_ui_config(const char *var, const char *value, void *cb)
 153{
 154        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 155                diff_use_color_default = git_config_colorbool(var, value);
 156                return 0;
 157        }
 158        if (!strcmp(var, "diff.context")) {
 159                diff_context_default = git_config_int(var, value);
 160                if (diff_context_default < 0)
 161                        return -1;
 162                return 0;
 163        }
 164        if (!strcmp(var, "diff.renames")) {
 165                diff_detect_rename_default = git_config_rename(var, value);
 166                return 0;
 167        }
 168        if (!strcmp(var, "diff.autorefreshindex")) {
 169                diff_auto_refresh_index = git_config_bool(var, value);
 170                return 0;
 171        }
 172        if (!strcmp(var, "diff.mnemonicprefix")) {
 173                diff_mnemonic_prefix = git_config_bool(var, value);
 174                return 0;
 175        }
 176        if (!strcmp(var, "diff.noprefix")) {
 177                diff_no_prefix = git_config_bool(var, value);
 178                return 0;
 179        }
 180        if (!strcmp(var, "diff.statgraphwidth")) {
 181                diff_stat_graph_width = git_config_int(var, value);
 182                return 0;
 183        }
 184        if (!strcmp(var, "diff.external"))
 185                return git_config_string(&external_diff_cmd_cfg, var, value);
 186        if (!strcmp(var, "diff.wordregex"))
 187                return git_config_string(&diff_word_regex_cfg, var, value);
 188
 189        if (!strcmp(var, "diff.ignoresubmodules"))
 190                handle_ignore_submodules_arg(&default_diff_options, value);
 191
 192        if (!strcmp(var, "diff.submodule")) {
 193                if (parse_submodule_params(&default_diff_options, value))
 194                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 195                                value);
 196                return 0;
 197        }
 198
 199        if (git_color_config(var, value, cb) < 0)
 200                return -1;
 201
 202        return git_diff_basic_config(var, value, cb);
 203}
 204
 205int git_diff_basic_config(const char *var, const char *value, void *cb)
 206{
 207        if (!strcmp(var, "diff.renamelimit")) {
 208                diff_rename_limit_default = git_config_int(var, value);
 209                return 0;
 210        }
 211
 212        if (userdiff_config(var, value) < 0)
 213                return -1;
 214
 215        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 216                int slot = parse_diff_color_slot(var, 11);
 217                if (slot < 0)
 218                        return 0;
 219                if (!value)
 220                        return config_error_nonbool(var);
 221                color_parse(value, var, diff_colors[slot]);
 222                return 0;
 223        }
 224
 225        /* like GNU diff's --suppress-blank-empty option  */
 226        if (!strcmp(var, "diff.suppressblankempty") ||
 227                        /* for backwards compatibility */
 228                        !strcmp(var, "diff.suppress-blank-empty")) {
 229                diff_suppress_blank_empty = git_config_bool(var, value);
 230                return 0;
 231        }
 232
 233        if (!strcmp(var, "diff.dirstat")) {
 234                struct strbuf errmsg = STRBUF_INIT;
 235                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 236                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 237                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 238                                errmsg.buf);
 239                strbuf_release(&errmsg);
 240                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 241                return 0;
 242        }
 243
 244        if (!prefixcmp(var, "submodule."))
 245                return parse_submodule_config_option(var, value);
 246
 247        return git_default_config(var, value, cb);
 248}
 249
 250static char *quote_two(const char *one, const char *two)
 251{
 252        int need_one = quote_c_style(one, NULL, NULL, 1);
 253        int need_two = quote_c_style(two, NULL, NULL, 1);
 254        struct strbuf res = STRBUF_INIT;
 255
 256        if (need_one + need_two) {
 257                strbuf_addch(&res, '"');
 258                quote_c_style(one, &res, NULL, 1);
 259                quote_c_style(two, &res, NULL, 1);
 260                strbuf_addch(&res, '"');
 261        } else {
 262                strbuf_addstr(&res, one);
 263                strbuf_addstr(&res, two);
 264        }
 265        return strbuf_detach(&res, NULL);
 266}
 267
 268static const char *external_diff(void)
 269{
 270        static const char *external_diff_cmd = NULL;
 271        static int done_preparing = 0;
 272
 273        if (done_preparing)
 274                return external_diff_cmd;
 275        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 276        if (!external_diff_cmd)
 277                external_diff_cmd = external_diff_cmd_cfg;
 278        done_preparing = 1;
 279        return external_diff_cmd;
 280}
 281
 282static struct diff_tempfile {
 283        const char *name; /* filename external diff should read from */
 284        char hex[41];
 285        char mode[10];
 286        char tmp_path[PATH_MAX];
 287} diff_temp[2];
 288
 289typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 290
 291struct emit_callback {
 292        int color_diff;
 293        unsigned ws_rule;
 294        int blank_at_eof_in_preimage;
 295        int blank_at_eof_in_postimage;
 296        int lno_in_preimage;
 297        int lno_in_postimage;
 298        sane_truncate_fn truncate;
 299        const char **label_path;
 300        struct diff_words_data *diff_words;
 301        struct diff_options *opt;
 302        int *found_changesp;
 303        struct strbuf *header;
 304};
 305
 306static int count_lines(const char *data, int size)
 307{
 308        int count, ch, completely_empty = 1, nl_just_seen = 0;
 309        count = 0;
 310        while (0 < size--) {
 311                ch = *data++;
 312                if (ch == '\n') {
 313                        count++;
 314                        nl_just_seen = 1;
 315                        completely_empty = 0;
 316                }
 317                else {
 318                        nl_just_seen = 0;
 319                        completely_empty = 0;
 320                }
 321        }
 322        if (completely_empty)
 323                return 0;
 324        if (!nl_just_seen)
 325                count++; /* no trailing newline */
 326        return count;
 327}
 328
 329static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 330{
 331        if (!DIFF_FILE_VALID(one)) {
 332                mf->ptr = (char *)""; /* does not matter */
 333                mf->size = 0;
 334                return 0;
 335        }
 336        else if (diff_populate_filespec(one, 0))
 337                return -1;
 338
 339        mf->ptr = one->data;
 340        mf->size = one->size;
 341        return 0;
 342}
 343
 344/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 345static unsigned long diff_filespec_size(struct diff_filespec *one)
 346{
 347        if (!DIFF_FILE_VALID(one))
 348                return 0;
 349        diff_populate_filespec(one, 1);
 350        return one->size;
 351}
 352
 353static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 354{
 355        char *ptr = mf->ptr;
 356        long size = mf->size;
 357        int cnt = 0;
 358
 359        if (!size)
 360                return cnt;
 361        ptr += size - 1; /* pointing at the very end */
 362        if (*ptr != '\n')
 363                ; /* incomplete line */
 364        else
 365                ptr--; /* skip the last LF */
 366        while (mf->ptr < ptr) {
 367                char *prev_eol;
 368                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 369                        if (*prev_eol == '\n')
 370                                break;
 371                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 372                        break;
 373                cnt++;
 374                ptr = prev_eol - 1;
 375        }
 376        return cnt;
 377}
 378
 379static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 380                               struct emit_callback *ecbdata)
 381{
 382        int l1, l2, at;
 383        unsigned ws_rule = ecbdata->ws_rule;
 384        l1 = count_trailing_blank(mf1, ws_rule);
 385        l2 = count_trailing_blank(mf2, ws_rule);
 386        if (l2 <= l1) {
 387                ecbdata->blank_at_eof_in_preimage = 0;
 388                ecbdata->blank_at_eof_in_postimage = 0;
 389                return;
 390        }
 391        at = count_lines(mf1->ptr, mf1->size);
 392        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 393
 394        at = count_lines(mf2->ptr, mf2->size);
 395        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 396}
 397
 398static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 399                        int first, const char *line, int len)
 400{
 401        int has_trailing_newline, has_trailing_carriage_return;
 402        int nofirst;
 403        FILE *file = o->file;
 404
 405        if (o->output_prefix) {
 406                struct strbuf *msg = NULL;
 407                msg = o->output_prefix(o, o->output_prefix_data);
 408                assert(msg);
 409                fwrite(msg->buf, msg->len, 1, file);
 410        }
 411
 412        if (len == 0) {
 413                has_trailing_newline = (first == '\n');
 414                has_trailing_carriage_return = (!has_trailing_newline &&
 415                                                (first == '\r'));
 416                nofirst = has_trailing_newline || has_trailing_carriage_return;
 417        } else {
 418                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 419                if (has_trailing_newline)
 420                        len--;
 421                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 422                if (has_trailing_carriage_return)
 423                        len--;
 424                nofirst = 0;
 425        }
 426
 427        if (len || !nofirst) {
 428                fputs(set, file);
 429                if (!nofirst)
 430                        fputc(first, file);
 431                fwrite(line, len, 1, file);
 432                fputs(reset, file);
 433        }
 434        if (has_trailing_carriage_return)
 435                fputc('\r', file);
 436        if (has_trailing_newline)
 437                fputc('\n', file);
 438}
 439
 440static void emit_line(struct diff_options *o, const char *set, const char *reset,
 441                      const char *line, int len)
 442{
 443        emit_line_0(o, set, reset, line[0], line+1, len-1);
 444}
 445
 446static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 447{
 448        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 449              ecbdata->blank_at_eof_in_preimage &&
 450              ecbdata->blank_at_eof_in_postimage &&
 451              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 452              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 453                return 0;
 454        return ws_blank_line(line, len, ecbdata->ws_rule);
 455}
 456
 457static void emit_add_line(const char *reset,
 458                          struct emit_callback *ecbdata,
 459                          const char *line, int len)
 460{
 461        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 462        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 463
 464        if (!*ws)
 465                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 466        else if (new_blank_line_at_eof(ecbdata, line, len))
 467                /* Blank line at EOF - paint '+' as well */
 468                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 469        else {
 470                /* Emit just the prefix, then the rest. */
 471                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 472                ws_check_emit(line, len, ecbdata->ws_rule,
 473                              ecbdata->opt->file, set, reset, ws);
 474        }
 475}
 476
 477static void emit_hunk_header(struct emit_callback *ecbdata,
 478                             const char *line, int len)
 479{
 480        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 481        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 482        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 483        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 484        static const char atat[2] = { '@', '@' };
 485        const char *cp, *ep;
 486        struct strbuf msgbuf = STRBUF_INIT;
 487        int org_len = len;
 488        int i = 1;
 489
 490        /*
 491         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 492         * it always is at least 10 bytes long.
 493         */
 494        if (len < 10 ||
 495            memcmp(line, atat, 2) ||
 496            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 497                emit_line(ecbdata->opt, plain, reset, line, len);
 498                return;
 499        }
 500        ep += 2; /* skip over @@ */
 501
 502        /* The hunk header in fraginfo color */
 503        strbuf_add(&msgbuf, frag, strlen(frag));
 504        strbuf_add(&msgbuf, line, ep - line);
 505        strbuf_add(&msgbuf, reset, strlen(reset));
 506
 507        /*
 508         * trailing "\r\n"
 509         */
 510        for ( ; i < 3; i++)
 511                if (line[len - i] == '\r' || line[len - i] == '\n')
 512                        len--;
 513
 514        /* blank before the func header */
 515        for (cp = ep; ep - line < len; ep++)
 516                if (*ep != ' ' && *ep != '\t')
 517                        break;
 518        if (ep != cp) {
 519                strbuf_add(&msgbuf, plain, strlen(plain));
 520                strbuf_add(&msgbuf, cp, ep - cp);
 521                strbuf_add(&msgbuf, reset, strlen(reset));
 522        }
 523
 524        if (ep < line + len) {
 525                strbuf_add(&msgbuf, func, strlen(func));
 526                strbuf_add(&msgbuf, ep, line + len - ep);
 527                strbuf_add(&msgbuf, reset, strlen(reset));
 528        }
 529
 530        strbuf_add(&msgbuf, line + len, org_len - len);
 531        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 532        strbuf_release(&msgbuf);
 533}
 534
 535static struct diff_tempfile *claim_diff_tempfile(void) {
 536        int i;
 537        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 538                if (!diff_temp[i].name)
 539                        return diff_temp + i;
 540        die("BUG: diff is failing to clean up its tempfiles");
 541}
 542
 543static int remove_tempfile_installed;
 544
 545static void remove_tempfile(void)
 546{
 547        int i;
 548        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 549                if (diff_temp[i].name == diff_temp[i].tmp_path)
 550                        unlink_or_warn(diff_temp[i].name);
 551                diff_temp[i].name = NULL;
 552        }
 553}
 554
 555static void remove_tempfile_on_signal(int signo)
 556{
 557        remove_tempfile();
 558        sigchain_pop(signo);
 559        raise(signo);
 560}
 561
 562static void print_line_count(FILE *file, int count)
 563{
 564        switch (count) {
 565        case 0:
 566                fprintf(file, "0,0");
 567                break;
 568        case 1:
 569                fprintf(file, "1");
 570                break;
 571        default:
 572                fprintf(file, "1,%d", count);
 573                break;
 574        }
 575}
 576
 577static void emit_rewrite_lines(struct emit_callback *ecb,
 578                               int prefix, const char *data, int size)
 579{
 580        const char *endp = NULL;
 581        static const char *nneof = " No newline at end of file\n";
 582        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 583        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 584
 585        while (0 < size) {
 586                int len;
 587
 588                endp = memchr(data, '\n', size);
 589                len = endp ? (endp - data + 1) : size;
 590                if (prefix != '+') {
 591                        ecb->lno_in_preimage++;
 592                        emit_line_0(ecb->opt, old, reset, '-',
 593                                    data, len);
 594                } else {
 595                        ecb->lno_in_postimage++;
 596                        emit_add_line(reset, ecb, data, len);
 597                }
 598                size -= len;
 599                data += len;
 600        }
 601        if (!endp) {
 602                const char *plain = diff_get_color(ecb->color_diff,
 603                                                   DIFF_PLAIN);
 604                putc('\n', ecb->opt->file);
 605                emit_line_0(ecb->opt, plain, reset, '\\',
 606                            nneof, strlen(nneof));
 607        }
 608}
 609
 610static void emit_rewrite_diff(const char *name_a,
 611                              const char *name_b,
 612                              struct diff_filespec *one,
 613                              struct diff_filespec *two,
 614                              struct userdiff_driver *textconv_one,
 615                              struct userdiff_driver *textconv_two,
 616                              struct diff_options *o)
 617{
 618        int lc_a, lc_b;
 619        const char *name_a_tab, *name_b_tab;
 620        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 621        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 622        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 623        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 624        const char *a_prefix, *b_prefix;
 625        char *data_one, *data_two;
 626        size_t size_one, size_two;
 627        struct emit_callback ecbdata;
 628        char *line_prefix = "";
 629        struct strbuf *msgbuf;
 630
 631        if (o && o->output_prefix) {
 632                msgbuf = o->output_prefix(o, o->output_prefix_data);
 633                line_prefix = msgbuf->buf;
 634        }
 635
 636        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 637                a_prefix = o->b_prefix;
 638                b_prefix = o->a_prefix;
 639        } else {
 640                a_prefix = o->a_prefix;
 641                b_prefix = o->b_prefix;
 642        }
 643
 644        name_a += (*name_a == '/');
 645        name_b += (*name_b == '/');
 646        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 647        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 648
 649        strbuf_reset(&a_name);
 650        strbuf_reset(&b_name);
 651        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 652        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 653
 654        size_one = fill_textconv(textconv_one, one, &data_one);
 655        size_two = fill_textconv(textconv_two, two, &data_two);
 656
 657        memset(&ecbdata, 0, sizeof(ecbdata));
 658        ecbdata.color_diff = want_color(o->use_color);
 659        ecbdata.found_changesp = &o->found_changes;
 660        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 661        ecbdata.opt = o;
 662        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 663                mmfile_t mf1, mf2;
 664                mf1.ptr = (char *)data_one;
 665                mf2.ptr = (char *)data_two;
 666                mf1.size = size_one;
 667                mf2.size = size_two;
 668                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 669        }
 670        ecbdata.lno_in_preimage = 1;
 671        ecbdata.lno_in_postimage = 1;
 672
 673        lc_a = count_lines(data_one, size_one);
 674        lc_b = count_lines(data_two, size_two);
 675        fprintf(o->file,
 676                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 677                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 678                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 679                line_prefix, fraginfo);
 680        if (!o->irreversible_delete)
 681                print_line_count(o->file, lc_a);
 682        else
 683                fprintf(o->file, "?,?");
 684        fprintf(o->file, " +");
 685        print_line_count(o->file, lc_b);
 686        fprintf(o->file, " @@%s\n", reset);
 687        if (lc_a && !o->irreversible_delete)
 688                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 689        if (lc_b)
 690                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 691        if (textconv_one)
 692                free((char *)data_one);
 693        if (textconv_two)
 694                free((char *)data_two);
 695}
 696
 697struct diff_words_buffer {
 698        mmfile_t text;
 699        long alloc;
 700        struct diff_words_orig {
 701                const char *begin, *end;
 702        } *orig;
 703        int orig_nr, orig_alloc;
 704};
 705
 706static void diff_words_append(char *line, unsigned long len,
 707                struct diff_words_buffer *buffer)
 708{
 709        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 710        line++;
 711        len--;
 712        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 713        buffer->text.size += len;
 714        buffer->text.ptr[buffer->text.size] = '\0';
 715}
 716
 717struct diff_words_style_elem {
 718        const char *prefix;
 719        const char *suffix;
 720        const char *color; /* NULL; filled in by the setup code if
 721                            * color is enabled */
 722};
 723
 724struct diff_words_style {
 725        enum diff_words_type type;
 726        struct diff_words_style_elem new, old, ctx;
 727        const char *newline;
 728};
 729
 730static struct diff_words_style diff_words_styles[] = {
 731        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 732        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 733        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 734};
 735
 736struct diff_words_data {
 737        struct diff_words_buffer minus, plus;
 738        const char *current_plus;
 739        int last_minus;
 740        struct diff_options *opt;
 741        regex_t *word_regex;
 742        enum diff_words_type type;
 743        struct diff_words_style *style;
 744};
 745
 746static int fn_out_diff_words_write_helper(FILE *fp,
 747                                          struct diff_words_style_elem *st_el,
 748                                          const char *newline,
 749                                          size_t count, const char *buf,
 750                                          const char *line_prefix)
 751{
 752        int print = 0;
 753
 754        while (count) {
 755                char *p = memchr(buf, '\n', count);
 756                if (print)
 757                        fputs(line_prefix, fp);
 758                if (p != buf) {
 759                        if (st_el->color && fputs(st_el->color, fp) < 0)
 760                                return -1;
 761                        if (fputs(st_el->prefix, fp) < 0 ||
 762                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 763                            fputs(st_el->suffix, fp) < 0)
 764                                return -1;
 765                        if (st_el->color && *st_el->color
 766                            && fputs(GIT_COLOR_RESET, fp) < 0)
 767                                return -1;
 768                }
 769                if (!p)
 770                        return 0;
 771                if (fputs(newline, fp) < 0)
 772                        return -1;
 773                count -= p + 1 - buf;
 774                buf = p + 1;
 775                print = 1;
 776        }
 777        return 0;
 778}
 779
 780/*
 781 * '--color-words' algorithm can be described as:
 782 *
 783 *   1. collect a the minus/plus lines of a diff hunk, divided into
 784 *      minus-lines and plus-lines;
 785 *
 786 *   2. break both minus-lines and plus-lines into words and
 787 *      place them into two mmfile_t with one word for each line;
 788 *
 789 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 790 *
 791 * And for the common parts of the both file, we output the plus side text.
 792 * diff_words->current_plus is used to trace the current position of the plus file
 793 * which printed. diff_words->last_minus is used to trace the last minus word
 794 * printed.
 795 *
 796 * For '--graph' to work with '--color-words', we need to output the graph prefix
 797 * on each line of color words output. Generally, there are two conditions on
 798 * which we should output the prefix.
 799 *
 800 *   1. diff_words->last_minus == 0 &&
 801 *      diff_words->current_plus == diff_words->plus.text.ptr
 802 *
 803 *      that is: the plus text must start as a new line, and if there is no minus
 804 *      word printed, a graph prefix must be printed.
 805 *
 806 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 807 *      *(diff_words->current_plus - 1) == '\n'
 808 *
 809 *      that is: a graph prefix must be printed following a '\n'
 810 */
 811static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 812{
 813        if ((diff_words->last_minus == 0 &&
 814                diff_words->current_plus == diff_words->plus.text.ptr) ||
 815                (diff_words->current_plus > diff_words->plus.text.ptr &&
 816                *(diff_words->current_plus - 1) == '\n')) {
 817                return 1;
 818        } else {
 819                return 0;
 820        }
 821}
 822
 823static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 824{
 825        struct diff_words_data *diff_words = priv;
 826        struct diff_words_style *style = diff_words->style;
 827        int minus_first, minus_len, plus_first, plus_len;
 828        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 829        struct diff_options *opt = diff_words->opt;
 830        struct strbuf *msgbuf;
 831        char *line_prefix = "";
 832
 833        if (line[0] != '@' || parse_hunk_header(line, len,
 834                        &minus_first, &minus_len, &plus_first, &plus_len))
 835                return;
 836
 837        assert(opt);
 838        if (opt->output_prefix) {
 839                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 840                line_prefix = msgbuf->buf;
 841        }
 842
 843        /* POSIX requires that first be decremented by one if len == 0... */
 844        if (minus_len) {
 845                minus_begin = diff_words->minus.orig[minus_first].begin;
 846                minus_end =
 847                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 848        } else
 849                minus_begin = minus_end =
 850                        diff_words->minus.orig[minus_first].end;
 851
 852        if (plus_len) {
 853                plus_begin = diff_words->plus.orig[plus_first].begin;
 854                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 855        } else
 856                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 857
 858        if (color_words_output_graph_prefix(diff_words)) {
 859                fputs(line_prefix, diff_words->opt->file);
 860        }
 861        if (diff_words->current_plus != plus_begin) {
 862                fn_out_diff_words_write_helper(diff_words->opt->file,
 863                                &style->ctx, style->newline,
 864                                plus_begin - diff_words->current_plus,
 865                                diff_words->current_plus, line_prefix);
 866                if (*(plus_begin - 1) == '\n')
 867                        fputs(line_prefix, diff_words->opt->file);
 868        }
 869        if (minus_begin != minus_end) {
 870                fn_out_diff_words_write_helper(diff_words->opt->file,
 871                                &style->old, style->newline,
 872                                minus_end - minus_begin, minus_begin,
 873                                line_prefix);
 874        }
 875        if (plus_begin != plus_end) {
 876                fn_out_diff_words_write_helper(diff_words->opt->file,
 877                                &style->new, style->newline,
 878                                plus_end - plus_begin, plus_begin,
 879                                line_prefix);
 880        }
 881
 882        diff_words->current_plus = plus_end;
 883        diff_words->last_minus = minus_first;
 884}
 885
 886/* This function starts looking at *begin, and returns 0 iff a word was found. */
 887static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 888                int *begin, int *end)
 889{
 890        if (word_regex && *begin < buffer->size) {
 891                regmatch_t match[1];
 892                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 893                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 894                                        '\n', match[0].rm_eo - match[0].rm_so);
 895                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 896                        *begin += match[0].rm_so;
 897                        return *begin >= *end;
 898                }
 899                return -1;
 900        }
 901
 902        /* find the next word */
 903        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 904                (*begin)++;
 905        if (*begin >= buffer->size)
 906                return -1;
 907
 908        /* find the end of the word */
 909        *end = *begin + 1;
 910        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 911                (*end)++;
 912
 913        return 0;
 914}
 915
 916/*
 917 * This function splits the words in buffer->text, stores the list with
 918 * newline separator into out, and saves the offsets of the original words
 919 * in buffer->orig.
 920 */
 921static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 922                regex_t *word_regex)
 923{
 924        int i, j;
 925        long alloc = 0;
 926
 927        out->size = 0;
 928        out->ptr = NULL;
 929
 930        /* fake an empty "0th" word */
 931        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 932        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 933        buffer->orig_nr = 1;
 934
 935        for (i = 0; i < buffer->text.size; i++) {
 936                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 937                        return;
 938
 939                /* store original boundaries */
 940                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 941                                buffer->orig_alloc);
 942                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 943                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 944                buffer->orig_nr++;
 945
 946                /* store one word */
 947                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 948                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 949                out->ptr[out->size + j - i] = '\n';
 950                out->size += j - i + 1;
 951
 952                i = j - 1;
 953        }
 954}
 955
 956/* this executes the word diff on the accumulated buffers */
 957static void diff_words_show(struct diff_words_data *diff_words)
 958{
 959        xpparam_t xpp;
 960        xdemitconf_t xecfg;
 961        mmfile_t minus, plus;
 962        struct diff_words_style *style = diff_words->style;
 963
 964        struct diff_options *opt = diff_words->opt;
 965        struct strbuf *msgbuf;
 966        char *line_prefix = "";
 967
 968        assert(opt);
 969        if (opt->output_prefix) {
 970                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 971                line_prefix = msgbuf->buf;
 972        }
 973
 974        /* special case: only removal */
 975        if (!diff_words->plus.text.size) {
 976                fputs(line_prefix, diff_words->opt->file);
 977                fn_out_diff_words_write_helper(diff_words->opt->file,
 978                        &style->old, style->newline,
 979                        diff_words->minus.text.size,
 980                        diff_words->minus.text.ptr, line_prefix);
 981                diff_words->minus.text.size = 0;
 982                return;
 983        }
 984
 985        diff_words->current_plus = diff_words->plus.text.ptr;
 986        diff_words->last_minus = 0;
 987
 988        memset(&xpp, 0, sizeof(xpp));
 989        memset(&xecfg, 0, sizeof(xecfg));
 990        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 991        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 992        xpp.flags = 0;
 993        /* as only the hunk header will be parsed, we need a 0-context */
 994        xecfg.ctxlen = 0;
 995        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 996                      &xpp, &xecfg);
 997        free(minus.ptr);
 998        free(plus.ptr);
 999        if (diff_words->current_plus != diff_words->plus.text.ptr +
1000                        diff_words->plus.text.size) {
1001                if (color_words_output_graph_prefix(diff_words))
1002                        fputs(line_prefix, diff_words->opt->file);
1003                fn_out_diff_words_write_helper(diff_words->opt->file,
1004                        &style->ctx, style->newline,
1005                        diff_words->plus.text.ptr + diff_words->plus.text.size
1006                        - diff_words->current_plus, diff_words->current_plus,
1007                        line_prefix);
1008        }
1009        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1010}
1011
1012/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1013static void diff_words_flush(struct emit_callback *ecbdata)
1014{
1015        if (ecbdata->diff_words->minus.text.size ||
1016            ecbdata->diff_words->plus.text.size)
1017                diff_words_show(ecbdata->diff_words);
1018}
1019
1020static void diff_filespec_load_driver(struct diff_filespec *one)
1021{
1022        /* Use already-loaded driver */
1023        if (one->driver)
1024                return;
1025
1026        if (S_ISREG(one->mode))
1027                one->driver = userdiff_find_by_path(one->path);
1028
1029        /* Fallback to default settings */
1030        if (!one->driver)
1031                one->driver = userdiff_find_by_name("default");
1032}
1033
1034static const char *userdiff_word_regex(struct diff_filespec *one)
1035{
1036        diff_filespec_load_driver(one);
1037        return one->driver->word_regex;
1038}
1039
1040static void init_diff_words_data(struct emit_callback *ecbdata,
1041                                 struct diff_options *orig_opts,
1042                                 struct diff_filespec *one,
1043                                 struct diff_filespec *two)
1044{
1045        int i;
1046        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1047        memcpy(o, orig_opts, sizeof(struct diff_options));
1048
1049        ecbdata->diff_words =
1050                xcalloc(1, sizeof(struct diff_words_data));
1051        ecbdata->diff_words->type = o->word_diff;
1052        ecbdata->diff_words->opt = o;
1053        if (!o->word_regex)
1054                o->word_regex = userdiff_word_regex(one);
1055        if (!o->word_regex)
1056                o->word_regex = userdiff_word_regex(two);
1057        if (!o->word_regex)
1058                o->word_regex = diff_word_regex_cfg;
1059        if (o->word_regex) {
1060                ecbdata->diff_words->word_regex = (regex_t *)
1061                        xmalloc(sizeof(regex_t));
1062                if (regcomp(ecbdata->diff_words->word_regex,
1063                            o->word_regex,
1064                            REG_EXTENDED | REG_NEWLINE))
1065                        die ("Invalid regular expression: %s",
1066                             o->word_regex);
1067        }
1068        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1069                if (o->word_diff == diff_words_styles[i].type) {
1070                        ecbdata->diff_words->style =
1071                                &diff_words_styles[i];
1072                        break;
1073                }
1074        }
1075        if (want_color(o->use_color)) {
1076                struct diff_words_style *st = ecbdata->diff_words->style;
1077                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1078                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1079                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1080        }
1081}
1082
1083static void free_diff_words_data(struct emit_callback *ecbdata)
1084{
1085        if (ecbdata->diff_words) {
1086                diff_words_flush(ecbdata);
1087                free (ecbdata->diff_words->opt);
1088                free (ecbdata->diff_words->minus.text.ptr);
1089                free (ecbdata->diff_words->minus.orig);
1090                free (ecbdata->diff_words->plus.text.ptr);
1091                free (ecbdata->diff_words->plus.orig);
1092                if (ecbdata->diff_words->word_regex) {
1093                        regfree(ecbdata->diff_words->word_regex);
1094                        free(ecbdata->diff_words->word_regex);
1095                }
1096                free(ecbdata->diff_words);
1097                ecbdata->diff_words = NULL;
1098        }
1099}
1100
1101const char *diff_get_color(int diff_use_color, enum color_diff ix)
1102{
1103        if (want_color(diff_use_color))
1104                return diff_colors[ix];
1105        return "";
1106}
1107
1108static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1109{
1110        const char *cp;
1111        unsigned long allot;
1112        size_t l = len;
1113
1114        if (ecb->truncate)
1115                return ecb->truncate(line, len);
1116        cp = line;
1117        allot = l;
1118        while (0 < l) {
1119                (void) utf8_width(&cp, &l);
1120                if (!cp)
1121                        break; /* truncated in the middle? */
1122        }
1123        return allot - l;
1124}
1125
1126static void find_lno(const char *line, struct emit_callback *ecbdata)
1127{
1128        const char *p;
1129        ecbdata->lno_in_preimage = 0;
1130        ecbdata->lno_in_postimage = 0;
1131        p = strchr(line, '-');
1132        if (!p)
1133                return; /* cannot happen */
1134        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1135        p = strchr(p, '+');
1136        if (!p)
1137                return; /* cannot happen */
1138        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1139}
1140
1141static void fn_out_consume(void *priv, char *line, unsigned long len)
1142{
1143        struct emit_callback *ecbdata = priv;
1144        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1145        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1146        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1147        struct diff_options *o = ecbdata->opt;
1148        char *line_prefix = "";
1149        struct strbuf *msgbuf;
1150
1151        if (o && o->output_prefix) {
1152                msgbuf = o->output_prefix(o, o->output_prefix_data);
1153                line_prefix = msgbuf->buf;
1154        }
1155
1156        if (ecbdata->header) {
1157                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1158                strbuf_reset(ecbdata->header);
1159                ecbdata->header = NULL;
1160        }
1161        *(ecbdata->found_changesp) = 1;
1162
1163        if (ecbdata->label_path[0]) {
1164                const char *name_a_tab, *name_b_tab;
1165
1166                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1167                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1168
1169                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1170                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1171                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1172                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1173                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1174        }
1175
1176        if (diff_suppress_blank_empty
1177            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1178                line[0] = '\n';
1179                len = 1;
1180        }
1181
1182        if (line[0] == '@') {
1183                if (ecbdata->diff_words)
1184                        diff_words_flush(ecbdata);
1185                len = sane_truncate_line(ecbdata, line, len);
1186                find_lno(line, ecbdata);
1187                emit_hunk_header(ecbdata, line, len);
1188                if (line[len-1] != '\n')
1189                        putc('\n', ecbdata->opt->file);
1190                return;
1191        }
1192
1193        if (len < 1) {
1194                emit_line(ecbdata->opt, reset, reset, line, len);
1195                if (ecbdata->diff_words
1196                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1197                        fputs("~\n", ecbdata->opt->file);
1198                return;
1199        }
1200
1201        if (ecbdata->diff_words) {
1202                if (line[0] == '-') {
1203                        diff_words_append(line, len,
1204                                          &ecbdata->diff_words->minus);
1205                        return;
1206                } else if (line[0] == '+') {
1207                        diff_words_append(line, len,
1208                                          &ecbdata->diff_words->plus);
1209                        return;
1210                } else if (!prefixcmp(line, "\\ ")) {
1211                        /*
1212                         * Eat the "no newline at eof" marker as if we
1213                         * saw a "+" or "-" line with nothing on it,
1214                         * and return without diff_words_flush() to
1215                         * defer processing. If this is the end of
1216                         * preimage, more "+" lines may come after it.
1217                         */
1218                        return;
1219                }
1220                diff_words_flush(ecbdata);
1221                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1222                        emit_line(ecbdata->opt, plain, reset, line, len);
1223                        fputs("~\n", ecbdata->opt->file);
1224                } else {
1225                        /*
1226                         * Skip the prefix character, if any.  With
1227                         * diff_suppress_blank_empty, there may be
1228                         * none.
1229                         */
1230                        if (line[0] != '\n') {
1231                              line++;
1232                              len--;
1233                        }
1234                        emit_line(ecbdata->opt, plain, reset, line, len);
1235                }
1236                return;
1237        }
1238
1239        if (line[0] != '+') {
1240                const char *color =
1241                        diff_get_color(ecbdata->color_diff,
1242                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1243                ecbdata->lno_in_preimage++;
1244                if (line[0] == ' ')
1245                        ecbdata->lno_in_postimage++;
1246                emit_line(ecbdata->opt, color, reset, line, len);
1247        } else {
1248                ecbdata->lno_in_postimage++;
1249                emit_add_line(reset, ecbdata, line + 1, len - 1);
1250        }
1251}
1252
1253static char *pprint_rename(const char *a, const char *b)
1254{
1255        const char *old = a;
1256        const char *new = b;
1257        struct strbuf name = STRBUF_INIT;
1258        int pfx_length, sfx_length;
1259        int len_a = strlen(a);
1260        int len_b = strlen(b);
1261        int a_midlen, b_midlen;
1262        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1263        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1264
1265        if (qlen_a || qlen_b) {
1266                quote_c_style(a, &name, NULL, 0);
1267                strbuf_addstr(&name, " => ");
1268                quote_c_style(b, &name, NULL, 0);
1269                return strbuf_detach(&name, NULL);
1270        }
1271
1272        /* Find common prefix */
1273        pfx_length = 0;
1274        while (*old && *new && *old == *new) {
1275                if (*old == '/')
1276                        pfx_length = old - a + 1;
1277                old++;
1278                new++;
1279        }
1280
1281        /* Find common suffix */
1282        old = a + len_a;
1283        new = b + len_b;
1284        sfx_length = 0;
1285        while (a <= old && b <= new && *old == *new) {
1286                if (*old == '/')
1287                        sfx_length = len_a - (old - a);
1288                old--;
1289                new--;
1290        }
1291
1292        /*
1293         * pfx{mid-a => mid-b}sfx
1294         * {pfx-a => pfx-b}sfx
1295         * pfx{sfx-a => sfx-b}
1296         * name-a => name-b
1297         */
1298        a_midlen = len_a - pfx_length - sfx_length;
1299        b_midlen = len_b - pfx_length - sfx_length;
1300        if (a_midlen < 0)
1301                a_midlen = 0;
1302        if (b_midlen < 0)
1303                b_midlen = 0;
1304
1305        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1306        if (pfx_length + sfx_length) {
1307                strbuf_add(&name, a, pfx_length);
1308                strbuf_addch(&name, '{');
1309        }
1310        strbuf_add(&name, a + pfx_length, a_midlen);
1311        strbuf_addstr(&name, " => ");
1312        strbuf_add(&name, b + pfx_length, b_midlen);
1313        if (pfx_length + sfx_length) {
1314                strbuf_addch(&name, '}');
1315                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1316        }
1317        return strbuf_detach(&name, NULL);
1318}
1319
1320struct diffstat_t {
1321        int nr;
1322        int alloc;
1323        struct diffstat_file {
1324                char *from_name;
1325                char *name;
1326                char *print_name;
1327                unsigned is_unmerged:1;
1328                unsigned is_binary:1;
1329                unsigned is_renamed:1;
1330                unsigned is_interesting:1;
1331                uintmax_t added, deleted;
1332        } **files;
1333};
1334
1335static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1336                                          const char *name_a,
1337                                          const char *name_b)
1338{
1339        struct diffstat_file *x;
1340        x = xcalloc(sizeof (*x), 1);
1341        if (diffstat->nr == diffstat->alloc) {
1342                diffstat->alloc = alloc_nr(diffstat->alloc);
1343                diffstat->files = xrealloc(diffstat->files,
1344                                diffstat->alloc * sizeof(x));
1345        }
1346        diffstat->files[diffstat->nr++] = x;
1347        if (name_b) {
1348                x->from_name = xstrdup(name_a);
1349                x->name = xstrdup(name_b);
1350                x->is_renamed = 1;
1351        }
1352        else {
1353                x->from_name = NULL;
1354                x->name = xstrdup(name_a);
1355        }
1356        return x;
1357}
1358
1359static void diffstat_consume(void *priv, char *line, unsigned long len)
1360{
1361        struct diffstat_t *diffstat = priv;
1362        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1363
1364        if (line[0] == '+')
1365                x->added++;
1366        else if (line[0] == '-')
1367                x->deleted++;
1368}
1369
1370const char mime_boundary_leader[] = "------------";
1371
1372static int scale_linear(int it, int width, int max_change)
1373{
1374        if (!it)
1375                return 0;
1376        /*
1377         * make sure that at least one '-' or '+' is printed if
1378         * there is any change to this path. The easiest way is to
1379         * scale linearly as if the alloted width is one column shorter
1380         * than it is, and then add 1 to the result.
1381         */
1382        return 1 + (it * (width - 1) / max_change);
1383}
1384
1385static void show_name(FILE *file,
1386                      const char *prefix, const char *name, int len)
1387{
1388        fprintf(file, " %s%-*s |", prefix, len, name);
1389}
1390
1391static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1392{
1393        if (cnt <= 0)
1394                return;
1395        fprintf(file, "%s", set);
1396        while (cnt--)
1397                putc(ch, file);
1398        fprintf(file, "%s", reset);
1399}
1400
1401static void fill_print_name(struct diffstat_file *file)
1402{
1403        char *pname;
1404
1405        if (file->print_name)
1406                return;
1407
1408        if (!file->is_renamed) {
1409                struct strbuf buf = STRBUF_INIT;
1410                if (quote_c_style(file->name, &buf, NULL, 0)) {
1411                        pname = strbuf_detach(&buf, NULL);
1412                } else {
1413                        pname = file->name;
1414                        strbuf_release(&buf);
1415                }
1416        } else {
1417                pname = pprint_rename(file->from_name, file->name);
1418        }
1419        file->print_name = pname;
1420}
1421
1422int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1423{
1424        struct strbuf sb = STRBUF_INIT;
1425        int ret;
1426
1427        if (!files) {
1428                assert(insertions == 0 && deletions == 0);
1429                return fprintf(fp, "%s\n", " 0 files changed");
1430        }
1431
1432        strbuf_addf(&sb,
1433                    (files == 1) ? " %d file changed" : " %d files changed",
1434                    files);
1435
1436        /*
1437         * For binary diff, the caller may want to print "x files
1438         * changed" with insertions == 0 && deletions == 0.
1439         *
1440         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1441         * is probably less confusing (i.e skip over "2 files changed
1442         * but nothing about added/removed lines? Is this a bug in Git?").
1443         */
1444        if (insertions || deletions == 0) {
1445                /*
1446                 * TRANSLATORS: "+" in (+) is a line addition marker;
1447                 * do not translate it.
1448                 */
1449                strbuf_addf(&sb,
1450                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1451                            insertions);
1452        }
1453
1454        if (deletions || insertions == 0) {
1455                /*
1456                 * TRANSLATORS: "-" in (-) is a line removal marker;
1457                 * do not translate it.
1458                 */
1459                strbuf_addf(&sb,
1460                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1461                            deletions);
1462        }
1463        strbuf_addch(&sb, '\n');
1464        ret = fputs(sb.buf, fp);
1465        strbuf_release(&sb);
1466        return ret;
1467}
1468
1469static void show_stats(struct diffstat_t *data, struct diff_options *options)
1470{
1471        int i, len, add, del, adds = 0, dels = 0;
1472        uintmax_t max_change = 0, max_len = 0;
1473        int total_files = data->nr, count;
1474        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1475        const char *reset, *add_c, *del_c;
1476        const char *line_prefix = "";
1477        int extra_shown = 0;
1478        struct strbuf *msg = NULL;
1479
1480        if (data->nr == 0)
1481                return;
1482
1483        if (options->output_prefix) {
1484                msg = options->output_prefix(options, options->output_prefix_data);
1485                line_prefix = msg->buf;
1486        }
1487
1488        count = options->stat_count ? options->stat_count : data->nr;
1489
1490        reset = diff_get_color_opt(options, DIFF_RESET);
1491        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1492        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1493
1494        /*
1495         * Find the longest filename and max number of changes
1496         */
1497        for (i = 0; (i < count) && (i < data->nr); i++) {
1498                struct diffstat_file *file = data->files[i];
1499                uintmax_t change = file->added + file->deleted;
1500
1501                if (!file->is_interesting && (change == 0)) {
1502                        count++; /* not shown == room for one more */
1503                        continue;
1504                }
1505                fill_print_name(file);
1506                len = strlen(file->print_name);
1507                if (max_len < len)
1508                        max_len = len;
1509
1510                if (file->is_unmerged) {
1511                        /* "Unmerged" is 8 characters */
1512                        bin_width = bin_width < 8 ? 8 : bin_width;
1513                        continue;
1514                }
1515                if (file->is_binary) {
1516                        /* "Bin XXX -> YYY bytes" */
1517                        int w = 14 + decimal_width(file->added)
1518                                + decimal_width(file->deleted);
1519                        bin_width = bin_width < w ? w : bin_width;
1520                        /* Display change counts aligned with "Bin" */
1521                        number_width = 3;
1522                        continue;
1523                }
1524
1525                if (max_change < change)
1526                        max_change = change;
1527        }
1528        count = i; /* where we can stop scanning in data->files[] */
1529
1530        /*
1531         * We have width = stat_width or term_columns() columns total.
1532         * We want a maximum of min(max_len, stat_name_width) for the name part.
1533         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1534         * We also need 1 for " " and 4 + decimal_width(max_change)
1535         * for " | NNNN " and one the empty column at the end, altogether
1536         * 6 + decimal_width(max_change).
1537         *
1538         * If there's not enough space, we will use the smaller of
1539         * stat_name_width (if set) and 5/8*width for the filename,
1540         * and the rest for constant elements + graph part, but no more
1541         * than stat_graph_width for the graph part.
1542         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1543         * for the standard terminal size).
1544         *
1545         * In other words: stat_width limits the maximum width, and
1546         * stat_name_width fixes the maximum width of the filename,
1547         * and is also used to divide available columns if there
1548         * aren't enough.
1549         *
1550         * Binary files are displayed with "Bin XXX -> YYY bytes"
1551         * instead of the change count and graph. This part is treated
1552         * similarly to the graph part, except that it is not
1553         * "scaled". If total width is too small to accomodate the
1554         * guaranteed minimum width of the filename part and the
1555         * separators and this message, this message will "overflow"
1556         * making the line longer than the maximum width.
1557         */
1558
1559        if (options->stat_width == -1)
1560                width = term_columns() - options->output_prefix_length;
1561        else
1562                width = options->stat_width ? options->stat_width : 80;
1563        number_width = decimal_width(max_change) > number_width ?
1564                decimal_width(max_change) : number_width;
1565
1566        if (options->stat_graph_width == -1)
1567                options->stat_graph_width = diff_stat_graph_width;
1568
1569        /*
1570         * Guarantee 3/8*16==6 for the graph part
1571         * and 5/8*16==10 for the filename part
1572         */
1573        if (width < 16 + 6 + number_width)
1574                width = 16 + 6 + number_width;
1575
1576        /*
1577         * First assign sizes that are wanted, ignoring available width.
1578         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1579         * starting from "XXX" should fit in graph_width.
1580         */
1581        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1582        if (options->stat_graph_width &&
1583            options->stat_graph_width < graph_width)
1584                graph_width = options->stat_graph_width;
1585
1586        name_width = (options->stat_name_width > 0 &&
1587                      options->stat_name_width < max_len) ?
1588                options->stat_name_width : max_len;
1589
1590        /*
1591         * Adjust adjustable widths not to exceed maximum width
1592         */
1593        if (name_width + number_width + 6 + graph_width > width) {
1594                if (graph_width > width * 3/8 - number_width - 6) {
1595                        graph_width = width * 3/8 - number_width - 6;
1596                        if (graph_width < 6)
1597                                graph_width = 6;
1598                }
1599
1600                if (options->stat_graph_width &&
1601                    graph_width > options->stat_graph_width)
1602                        graph_width = options->stat_graph_width;
1603                if (name_width > width - number_width - 6 - graph_width)
1604                        name_width = width - number_width - 6 - graph_width;
1605                else
1606                        graph_width = width - number_width - 6 - name_width;
1607        }
1608
1609        /*
1610         * From here name_width is the width of the name area,
1611         * and graph_width is the width of the graph area.
1612         * max_change is used to scale graph properly.
1613         */
1614        for (i = 0; i < count; i++) {
1615                const char *prefix = "";
1616                struct diffstat_file *file = data->files[i];
1617                char *name = file->print_name;
1618                uintmax_t added = file->added;
1619                uintmax_t deleted = file->deleted;
1620                int name_len;
1621
1622                if (!file->is_interesting && (added + deleted == 0))
1623                        continue;
1624
1625                /*
1626                 * "scale" the filename
1627                 */
1628                len = name_width;
1629                name_len = strlen(name);
1630                if (name_width < name_len) {
1631                        char *slash;
1632                        prefix = "...";
1633                        len -= 3;
1634                        name += name_len - len;
1635                        slash = strchr(name, '/');
1636                        if (slash)
1637                                name = slash;
1638                }
1639
1640                if (file->is_binary) {
1641                        fprintf(options->file, "%s", line_prefix);
1642                        show_name(options->file, prefix, name, len);
1643                        fprintf(options->file, " %*s", number_width, "Bin");
1644                        if (!added && !deleted) {
1645                                putc('\n', options->file);
1646                                continue;
1647                        }
1648                        fprintf(options->file, " %s%"PRIuMAX"%s",
1649                                del_c, deleted, reset);
1650                        fprintf(options->file, " -> ");
1651                        fprintf(options->file, "%s%"PRIuMAX"%s",
1652                                add_c, added, reset);
1653                        fprintf(options->file, " bytes");
1654                        fprintf(options->file, "\n");
1655                        continue;
1656                }
1657                else if (file->is_unmerged) {
1658                        fprintf(options->file, "%s", line_prefix);
1659                        show_name(options->file, prefix, name, len);
1660                        fprintf(options->file, " Unmerged\n");
1661                        continue;
1662                }
1663
1664                /*
1665                 * scale the add/delete
1666                 */
1667                add = added;
1668                del = deleted;
1669
1670                if (graph_width <= max_change) {
1671                        int total = add + del;
1672
1673                        total = scale_linear(add + del, graph_width, max_change);
1674                        if (total < 2 && add && del)
1675                                /* width >= 2 due to the sanity check */
1676                                total = 2;
1677                        if (add < del) {
1678                                add = scale_linear(add, graph_width, max_change);
1679                                del = total - add;
1680                        } else {
1681                                del = scale_linear(del, graph_width, max_change);
1682                                add = total - del;
1683                        }
1684                }
1685                fprintf(options->file, "%s", line_prefix);
1686                show_name(options->file, prefix, name, len);
1687                fprintf(options->file, " %*"PRIuMAX"%s",
1688                        number_width, added + deleted,
1689                        added + deleted ? " " : "");
1690                show_graph(options->file, '+', add, add_c, reset);
1691                show_graph(options->file, '-', del, del_c, reset);
1692                fprintf(options->file, "\n");
1693        }
1694
1695        for (i = 0; i < data->nr; i++) {
1696                struct diffstat_file *file = data->files[i];
1697                uintmax_t added = file->added;
1698                uintmax_t deleted = file->deleted;
1699
1700                if (file->is_unmerged ||
1701                    (!file->is_interesting && (added + deleted == 0))) {
1702                        total_files--;
1703                        continue;
1704                }
1705
1706                if (!file->is_binary) {
1707                        adds += added;
1708                        dels += deleted;
1709                }
1710                if (i < count)
1711                        continue;
1712                if (!extra_shown)
1713                        fprintf(options->file, "%s ...\n", line_prefix);
1714                extra_shown = 1;
1715        }
1716        fprintf(options->file, "%s", line_prefix);
1717        print_stat_summary(options->file, total_files, adds, dels);
1718}
1719
1720static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1721{
1722        int i, adds = 0, dels = 0, total_files = data->nr;
1723
1724        if (data->nr == 0)
1725                return;
1726
1727        for (i = 0; i < data->nr; i++) {
1728                int added = data->files[i]->added;
1729                int deleted= data->files[i]->deleted;
1730
1731                if (data->files[i]->is_unmerged ||
1732                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1733                        total_files--;
1734                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1735                        adds += added;
1736                        dels += deleted;
1737                }
1738        }
1739        if (options->output_prefix) {
1740                struct strbuf *msg = NULL;
1741                msg = options->output_prefix(options,
1742                                options->output_prefix_data);
1743                fprintf(options->file, "%s", msg->buf);
1744        }
1745        print_stat_summary(options->file, total_files, adds, dels);
1746}
1747
1748static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1749{
1750        int i;
1751
1752        if (data->nr == 0)
1753                return;
1754
1755        for (i = 0; i < data->nr; i++) {
1756                struct diffstat_file *file = data->files[i];
1757
1758                if (options->output_prefix) {
1759                        struct strbuf *msg = NULL;
1760                        msg = options->output_prefix(options,
1761                                        options->output_prefix_data);
1762                        fprintf(options->file, "%s", msg->buf);
1763                }
1764
1765                if (file->is_binary)
1766                        fprintf(options->file, "-\t-\t");
1767                else
1768                        fprintf(options->file,
1769                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1770                                file->added, file->deleted);
1771                if (options->line_termination) {
1772                        fill_print_name(file);
1773                        if (!file->is_renamed)
1774                                write_name_quoted(file->name, options->file,
1775                                                  options->line_termination);
1776                        else {
1777                                fputs(file->print_name, options->file);
1778                                putc(options->line_termination, options->file);
1779                        }
1780                } else {
1781                        if (file->is_renamed) {
1782                                putc('\0', options->file);
1783                                write_name_quoted(file->from_name, options->file, '\0');
1784                        }
1785                        write_name_quoted(file->name, options->file, '\0');
1786                }
1787        }
1788}
1789
1790struct dirstat_file {
1791        const char *name;
1792        unsigned long changed;
1793};
1794
1795struct dirstat_dir {
1796        struct dirstat_file *files;
1797        int alloc, nr, permille, cumulative;
1798};
1799
1800static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1801                unsigned long changed, const char *base, int baselen)
1802{
1803        unsigned long this_dir = 0;
1804        unsigned int sources = 0;
1805        const char *line_prefix = "";
1806        struct strbuf *msg = NULL;
1807
1808        if (opt->output_prefix) {
1809                msg = opt->output_prefix(opt, opt->output_prefix_data);
1810                line_prefix = msg->buf;
1811        }
1812
1813        while (dir->nr) {
1814                struct dirstat_file *f = dir->files;
1815                int namelen = strlen(f->name);
1816                unsigned long this;
1817                char *slash;
1818
1819                if (namelen < baselen)
1820                        break;
1821                if (memcmp(f->name, base, baselen))
1822                        break;
1823                slash = strchr(f->name + baselen, '/');
1824                if (slash) {
1825                        int newbaselen = slash + 1 - f->name;
1826                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1827                        sources++;
1828                } else {
1829                        this = f->changed;
1830                        dir->files++;
1831                        dir->nr--;
1832                        sources += 2;
1833                }
1834                this_dir += this;
1835        }
1836
1837        /*
1838         * We don't report dirstat's for
1839         *  - the top level
1840         *  - or cases where everything came from a single directory
1841         *    under this directory (sources == 1).
1842         */
1843        if (baselen && sources != 1) {
1844                if (this_dir) {
1845                        int permille = this_dir * 1000 / changed;
1846                        if (permille >= dir->permille) {
1847                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1848                                        permille / 10, permille % 10, baselen, base);
1849                                if (!dir->cumulative)
1850                                        return 0;
1851                        }
1852                }
1853        }
1854        return this_dir;
1855}
1856
1857static int dirstat_compare(const void *_a, const void *_b)
1858{
1859        const struct dirstat_file *a = _a;
1860        const struct dirstat_file *b = _b;
1861        return strcmp(a->name, b->name);
1862}
1863
1864static void show_dirstat(struct diff_options *options)
1865{
1866        int i;
1867        unsigned long changed;
1868        struct dirstat_dir dir;
1869        struct diff_queue_struct *q = &diff_queued_diff;
1870
1871        dir.files = NULL;
1872        dir.alloc = 0;
1873        dir.nr = 0;
1874        dir.permille = options->dirstat_permille;
1875        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1876
1877        changed = 0;
1878        for (i = 0; i < q->nr; i++) {
1879                struct diff_filepair *p = q->queue[i];
1880                const char *name;
1881                unsigned long copied, added, damage;
1882                int content_changed;
1883
1884                name = p->two->path ? p->two->path : p->one->path;
1885
1886                if (p->one->sha1_valid && p->two->sha1_valid)
1887                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1888                else
1889                        content_changed = 1;
1890
1891                if (!content_changed) {
1892                        /*
1893                         * The SHA1 has not changed, so pre-/post-content is
1894                         * identical. We can therefore skip looking at the
1895                         * file contents altogether.
1896                         */
1897                        damage = 0;
1898                        goto found_damage;
1899                }
1900
1901                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1902                        /*
1903                         * In --dirstat-by-file mode, we don't really need to
1904                         * look at the actual file contents at all.
1905                         * The fact that the SHA1 changed is enough for us to
1906                         * add this file to the list of results
1907                         * (with each file contributing equal damage).
1908                         */
1909                        damage = 1;
1910                        goto found_damage;
1911                }
1912
1913                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1914                        diff_populate_filespec(p->one, 0);
1915                        diff_populate_filespec(p->two, 0);
1916                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1917                                               &copied, &added);
1918                        diff_free_filespec_data(p->one);
1919                        diff_free_filespec_data(p->two);
1920                } else if (DIFF_FILE_VALID(p->one)) {
1921                        diff_populate_filespec(p->one, 1);
1922                        copied = added = 0;
1923                        diff_free_filespec_data(p->one);
1924                } else if (DIFF_FILE_VALID(p->two)) {
1925                        diff_populate_filespec(p->two, 1);
1926                        copied = 0;
1927                        added = p->two->size;
1928                        diff_free_filespec_data(p->two);
1929                } else
1930                        continue;
1931
1932                /*
1933                 * Original minus copied is the removed material,
1934                 * added is the new material.  They are both damages
1935                 * made to the preimage.
1936                 * If the resulting damage is zero, we know that
1937                 * diffcore_count_changes() considers the two entries to
1938                 * be identical, but since content_changed is true, we
1939                 * know that there must have been _some_ kind of change,
1940                 * so we force all entries to have damage > 0.
1941                 */
1942                damage = (p->one->size - copied) + added;
1943                if (!damage)
1944                        damage = 1;
1945
1946found_damage:
1947                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1948                dir.files[dir.nr].name = name;
1949                dir.files[dir.nr].changed = damage;
1950                changed += damage;
1951                dir.nr++;
1952        }
1953
1954        /* This can happen even with many files, if everything was renames */
1955        if (!changed)
1956                return;
1957
1958        /* Show all directories with more than x% of the changes */
1959        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1960        gather_dirstat(options, &dir, changed, "", 0);
1961}
1962
1963static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1964{
1965        int i;
1966        unsigned long changed;
1967        struct dirstat_dir dir;
1968
1969        if (data->nr == 0)
1970                return;
1971
1972        dir.files = NULL;
1973        dir.alloc = 0;
1974        dir.nr = 0;
1975        dir.permille = options->dirstat_permille;
1976        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1977
1978        changed = 0;
1979        for (i = 0; i < data->nr; i++) {
1980                struct diffstat_file *file = data->files[i];
1981                unsigned long damage = file->added + file->deleted;
1982                if (file->is_binary)
1983                        /*
1984                         * binary files counts bytes, not lines. Must find some
1985                         * way to normalize binary bytes vs. textual lines.
1986                         * The following heuristic assumes that there are 64
1987                         * bytes per "line".
1988                         * This is stupid and ugly, but very cheap...
1989                         */
1990                        damage = (damage + 63) / 64;
1991                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1992                dir.files[dir.nr].name = file->name;
1993                dir.files[dir.nr].changed = damage;
1994                changed += damage;
1995                dir.nr++;
1996        }
1997
1998        /* This can happen even with many files, if everything was renames */
1999        if (!changed)
2000                return;
2001
2002        /* Show all directories with more than x% of the changes */
2003        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2004        gather_dirstat(options, &dir, changed, "", 0);
2005}
2006
2007static void free_diffstat_info(struct diffstat_t *diffstat)
2008{
2009        int i;
2010        for (i = 0; i < diffstat->nr; i++) {
2011                struct diffstat_file *f = diffstat->files[i];
2012                if (f->name != f->print_name)
2013                        free(f->print_name);
2014                free(f->name);
2015                free(f->from_name);
2016                free(f);
2017        }
2018        free(diffstat->files);
2019}
2020
2021struct checkdiff_t {
2022        const char *filename;
2023        int lineno;
2024        int conflict_marker_size;
2025        struct diff_options *o;
2026        unsigned ws_rule;
2027        unsigned status;
2028};
2029
2030static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2031{
2032        char firstchar;
2033        int cnt;
2034
2035        if (len < marker_size + 1)
2036                return 0;
2037        firstchar = line[0];
2038        switch (firstchar) {
2039        case '=': case '>': case '<': case '|':
2040                break;
2041        default:
2042                return 0;
2043        }
2044        for (cnt = 1; cnt < marker_size; cnt++)
2045                if (line[cnt] != firstchar)
2046                        return 0;
2047        /* line[1] thru line[marker_size-1] are same as firstchar */
2048        if (len < marker_size + 1 || !isspace(line[marker_size]))
2049                return 0;
2050        return 1;
2051}
2052
2053static void checkdiff_consume(void *priv, char *line, unsigned long len)
2054{
2055        struct checkdiff_t *data = priv;
2056        int marker_size = data->conflict_marker_size;
2057        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2058        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2059        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2060        char *err;
2061        char *line_prefix = "";
2062        struct strbuf *msgbuf;
2063
2064        assert(data->o);
2065        if (data->o->output_prefix) {
2066                msgbuf = data->o->output_prefix(data->o,
2067                        data->o->output_prefix_data);
2068                line_prefix = msgbuf->buf;
2069        }
2070
2071        if (line[0] == '+') {
2072                unsigned bad;
2073                data->lineno++;
2074                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2075                        data->status |= 1;
2076                        fprintf(data->o->file,
2077                                "%s%s:%d: leftover conflict marker\n",
2078                                line_prefix, data->filename, data->lineno);
2079                }
2080                bad = ws_check(line + 1, len - 1, data->ws_rule);
2081                if (!bad)
2082                        return;
2083                data->status |= bad;
2084                err = whitespace_error_string(bad);
2085                fprintf(data->o->file, "%s%s:%d: %s.\n",
2086                        line_prefix, data->filename, data->lineno, err);
2087                free(err);
2088                emit_line(data->o, set, reset, line, 1);
2089                ws_check_emit(line + 1, len - 1, data->ws_rule,
2090                              data->o->file, set, reset, ws);
2091        } else if (line[0] == ' ') {
2092                data->lineno++;
2093        } else if (line[0] == '@') {
2094                char *plus = strchr(line, '+');
2095                if (plus)
2096                        data->lineno = strtol(plus, NULL, 10) - 1;
2097                else
2098                        die("invalid diff");
2099        }
2100}
2101
2102static unsigned char *deflate_it(char *data,
2103                                 unsigned long size,
2104                                 unsigned long *result_size)
2105{
2106        int bound;
2107        unsigned char *deflated;
2108        git_zstream stream;
2109
2110        memset(&stream, 0, sizeof(stream));
2111        git_deflate_init(&stream, zlib_compression_level);
2112        bound = git_deflate_bound(&stream, size);
2113        deflated = xmalloc(bound);
2114        stream.next_out = deflated;
2115        stream.avail_out = bound;
2116
2117        stream.next_in = (unsigned char *)data;
2118        stream.avail_in = size;
2119        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2120                ; /* nothing */
2121        git_deflate_end(&stream);
2122        *result_size = stream.total_out;
2123        return deflated;
2124}
2125
2126static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
2127{
2128        void *cp;
2129        void *delta;
2130        void *deflated;
2131        void *data;
2132        unsigned long orig_size;
2133        unsigned long delta_size;
2134        unsigned long deflate_size;
2135        unsigned long data_size;
2136
2137        /* We could do deflated delta, or we could do just deflated two,
2138         * whichever is smaller.
2139         */
2140        delta = NULL;
2141        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2142        if (one->size && two->size) {
2143                delta = diff_delta(one->ptr, one->size,
2144                                   two->ptr, two->size,
2145                                   &delta_size, deflate_size);
2146                if (delta) {
2147                        void *to_free = delta;
2148                        orig_size = delta_size;
2149                        delta = deflate_it(delta, delta_size, &delta_size);
2150                        free(to_free);
2151                }
2152        }
2153
2154        if (delta && delta_size < deflate_size) {
2155                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2156                free(deflated);
2157                data = delta;
2158                data_size = delta_size;
2159        }
2160        else {
2161                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2162                free(delta);
2163                data = deflated;
2164                data_size = deflate_size;
2165        }
2166
2167        /* emit data encoded in base85 */
2168        cp = data;
2169        while (data_size) {
2170                int bytes = (52 < data_size) ? 52 : data_size;
2171                char line[70];
2172                data_size -= bytes;
2173                if (bytes <= 26)
2174                        line[0] = bytes + 'A' - 1;
2175                else
2176                        line[0] = bytes - 26 + 'a' - 1;
2177                encode_85(line + 1, cp, bytes);
2178                cp = (char *) cp + bytes;
2179                fprintf(file, "%s", prefix);
2180                fputs(line, file);
2181                fputc('\n', file);
2182        }
2183        fprintf(file, "%s\n", prefix);
2184        free(data);
2185}
2186
2187static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
2188{
2189        fprintf(file, "%sGIT binary patch\n", prefix);
2190        emit_binary_diff_body(file, one, two, prefix);
2191        emit_binary_diff_body(file, two, one, prefix);
2192}
2193
2194int diff_filespec_is_binary(struct diff_filespec *one)
2195{
2196        if (one->is_binary == -1) {
2197                diff_filespec_load_driver(one);
2198                if (one->driver->binary != -1)
2199                        one->is_binary = one->driver->binary;
2200                else {
2201                        if (!one->data && DIFF_FILE_VALID(one))
2202                                diff_populate_filespec(one, 0);
2203                        if (one->data)
2204                                one->is_binary = buffer_is_binary(one->data,
2205                                                one->size);
2206                        if (one->is_binary == -1)
2207                                one->is_binary = 0;
2208                }
2209        }
2210        return one->is_binary;
2211}
2212
2213static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2214{
2215        diff_filespec_load_driver(one);
2216        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2217}
2218
2219void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2220{
2221        if (!options->a_prefix)
2222                options->a_prefix = a;
2223        if (!options->b_prefix)
2224                options->b_prefix = b;
2225}
2226
2227struct userdiff_driver *get_textconv(struct diff_filespec *one)
2228{
2229        if (!DIFF_FILE_VALID(one))
2230                return NULL;
2231
2232        diff_filespec_load_driver(one);
2233        return userdiff_get_textconv(one->driver);
2234}
2235
2236static void builtin_diff(const char *name_a,
2237                         const char *name_b,
2238                         struct diff_filespec *one,
2239                         struct diff_filespec *two,
2240                         const char *xfrm_msg,
2241                         int must_show_header,
2242                         struct diff_options *o,
2243                         int complete_rewrite)
2244{
2245        mmfile_t mf1, mf2;
2246        const char *lbl[2];
2247        char *a_one, *b_two;
2248        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2249        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2250        const char *a_prefix, *b_prefix;
2251        struct userdiff_driver *textconv_one = NULL;
2252        struct userdiff_driver *textconv_two = NULL;
2253        struct strbuf header = STRBUF_INIT;
2254        struct strbuf *msgbuf;
2255        char *line_prefix = "";
2256
2257        if (o->output_prefix) {
2258                msgbuf = o->output_prefix(o, o->output_prefix_data);
2259                line_prefix = msgbuf->buf;
2260        }
2261
2262        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2263                        (!one->mode || S_ISGITLINK(one->mode)) &&
2264                        (!two->mode || S_ISGITLINK(two->mode))) {
2265                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2266                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2267                show_submodule_summary(o->file, one ? one->path : two->path,
2268                                one->sha1, two->sha1, two->dirty_submodule,
2269                                meta, del, add, reset);
2270                return;
2271        }
2272
2273        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2274                textconv_one = get_textconv(one);
2275                textconv_two = get_textconv(two);
2276        }
2277
2278        diff_set_mnemonic_prefix(o, "a/", "b/");
2279        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2280                a_prefix = o->b_prefix;
2281                b_prefix = o->a_prefix;
2282        } else {
2283                a_prefix = o->a_prefix;
2284                b_prefix = o->b_prefix;
2285        }
2286
2287        /* Never use a non-valid filename anywhere if at all possible */
2288        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2289        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2290
2291        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2292        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2293        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2294        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2295        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2296        if (lbl[0][0] == '/') {
2297                /* /dev/null */
2298                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2299                if (xfrm_msg)
2300                        strbuf_addstr(&header, xfrm_msg);
2301                must_show_header = 1;
2302        }
2303        else if (lbl[1][0] == '/') {
2304                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2305                if (xfrm_msg)
2306                        strbuf_addstr(&header, xfrm_msg);
2307                must_show_header = 1;
2308        }
2309        else {
2310                if (one->mode != two->mode) {
2311                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2312                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2313                        must_show_header = 1;
2314                }
2315                if (xfrm_msg)
2316                        strbuf_addstr(&header, xfrm_msg);
2317
2318                /*
2319                 * we do not run diff between different kind
2320                 * of objects.
2321                 */
2322                if ((one->mode ^ two->mode) & S_IFMT)
2323                        goto free_ab_and_return;
2324                if (complete_rewrite &&
2325                    (textconv_one || !diff_filespec_is_binary(one)) &&
2326                    (textconv_two || !diff_filespec_is_binary(two))) {
2327                        fprintf(o->file, "%s", header.buf);
2328                        strbuf_reset(&header);
2329                        emit_rewrite_diff(name_a, name_b, one, two,
2330                                                textconv_one, textconv_two, o);
2331                        o->found_changes = 1;
2332                        goto free_ab_and_return;
2333                }
2334        }
2335
2336        if (o->irreversible_delete && lbl[1][0] == '/') {
2337                fprintf(o->file, "%s", header.buf);
2338                strbuf_reset(&header);
2339                goto free_ab_and_return;
2340        } else if (!DIFF_OPT_TST(o, TEXT) &&
2341            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2342              (!textconv_two && diff_filespec_is_binary(two)) )) {
2343                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2344                        die("unable to read files to diff");
2345                /* Quite common confusing case */
2346                if (mf1.size == mf2.size &&
2347                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2348                        if (must_show_header)
2349                                fprintf(o->file, "%s", header.buf);
2350                        goto free_ab_and_return;
2351                }
2352                fprintf(o->file, "%s", header.buf);
2353                strbuf_reset(&header);
2354                if (DIFF_OPT_TST(o, BINARY))
2355                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2356                else
2357                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2358                                line_prefix, lbl[0], lbl[1]);
2359                o->found_changes = 1;
2360        } else {
2361                /* Crazy xdl interfaces.. */
2362                const char *diffopts = getenv("GIT_DIFF_OPTS");
2363                xpparam_t xpp;
2364                xdemitconf_t xecfg;
2365                struct emit_callback ecbdata;
2366                const struct userdiff_funcname *pe;
2367
2368                if (must_show_header) {
2369                        fprintf(o->file, "%s", header.buf);
2370                        strbuf_reset(&header);
2371                }
2372
2373                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2374                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2375
2376                pe = diff_funcname_pattern(one);
2377                if (!pe)
2378                        pe = diff_funcname_pattern(two);
2379
2380                memset(&xpp, 0, sizeof(xpp));
2381                memset(&xecfg, 0, sizeof(xecfg));
2382                memset(&ecbdata, 0, sizeof(ecbdata));
2383                ecbdata.label_path = lbl;
2384                ecbdata.color_diff = want_color(o->use_color);
2385                ecbdata.found_changesp = &o->found_changes;
2386                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2387                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2388                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2389                ecbdata.opt = o;
2390                ecbdata.header = header.len ? &header : NULL;
2391                xpp.flags = o->xdl_opts;
2392                xecfg.ctxlen = o->context;
2393                xecfg.interhunkctxlen = o->interhunkcontext;
2394                xecfg.flags = XDL_EMIT_FUNCNAMES;
2395                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2396                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2397                if (pe)
2398                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2399                if (!diffopts)
2400                        ;
2401                else if (!prefixcmp(diffopts, "--unified="))
2402                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2403                else if (!prefixcmp(diffopts, "-u"))
2404                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2405                if (o->word_diff)
2406                        init_diff_words_data(&ecbdata, o, one, two);
2407                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2408                              &xpp, &xecfg);
2409                if (o->word_diff)
2410                        free_diff_words_data(&ecbdata);
2411                if (textconv_one)
2412                        free(mf1.ptr);
2413                if (textconv_two)
2414                        free(mf2.ptr);
2415                xdiff_clear_find_func(&xecfg);
2416        }
2417
2418 free_ab_and_return:
2419        strbuf_release(&header);
2420        diff_free_filespec_data(one);
2421        diff_free_filespec_data(two);
2422        free(a_one);
2423        free(b_two);
2424        return;
2425}
2426
2427static void builtin_diffstat(const char *name_a, const char *name_b,
2428                             struct diff_filespec *one,
2429                             struct diff_filespec *two,
2430                             struct diffstat_t *diffstat,
2431                             struct diff_options *o,
2432                             struct diff_filepair *p)
2433{
2434        mmfile_t mf1, mf2;
2435        struct diffstat_file *data;
2436        int same_contents;
2437        int complete_rewrite = 0;
2438
2439        if (!DIFF_PAIR_UNMERGED(p)) {
2440                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2441                        complete_rewrite = 1;
2442        }
2443
2444        data = diffstat_add(diffstat, name_a, name_b);
2445        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2446
2447        if (!one || !two) {
2448                data->is_unmerged = 1;
2449                return;
2450        }
2451
2452        same_contents = !hashcmp(one->sha1, two->sha1);
2453
2454        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2455                data->is_binary = 1;
2456                if (same_contents) {
2457                        data->added = 0;
2458                        data->deleted = 0;
2459                } else {
2460                        data->added = diff_filespec_size(two);
2461                        data->deleted = diff_filespec_size(one);
2462                }
2463        }
2464
2465        else if (complete_rewrite) {
2466                diff_populate_filespec(one, 0);
2467                diff_populate_filespec(two, 0);
2468                data->deleted = count_lines(one->data, one->size);
2469                data->added = count_lines(two->data, two->size);
2470        }
2471
2472        else if (!same_contents) {
2473                /* Crazy xdl interfaces.. */
2474                xpparam_t xpp;
2475                xdemitconf_t xecfg;
2476
2477                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2478                        die("unable to read files to diff");
2479
2480                memset(&xpp, 0, sizeof(xpp));
2481                memset(&xecfg, 0, sizeof(xecfg));
2482                xpp.flags = o->xdl_opts;
2483                xecfg.ctxlen = o->context;
2484                xecfg.interhunkctxlen = o->interhunkcontext;
2485                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2486                              &xpp, &xecfg);
2487        }
2488
2489        diff_free_filespec_data(one);
2490        diff_free_filespec_data(two);
2491}
2492
2493static void builtin_checkdiff(const char *name_a, const char *name_b,
2494                              const char *attr_path,
2495                              struct diff_filespec *one,
2496                              struct diff_filespec *two,
2497                              struct diff_options *o)
2498{
2499        mmfile_t mf1, mf2;
2500        struct checkdiff_t data;
2501
2502        if (!two)
2503                return;
2504
2505        memset(&data, 0, sizeof(data));
2506        data.filename = name_b ? name_b : name_a;
2507        data.lineno = 0;
2508        data.o = o;
2509        data.ws_rule = whitespace_rule(attr_path);
2510        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2511
2512        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2513                die("unable to read files to diff");
2514
2515        /*
2516         * All the other codepaths check both sides, but not checking
2517         * the "old" side here is deliberate.  We are checking the newly
2518         * introduced changes, and as long as the "new" side is text, we
2519         * can and should check what it introduces.
2520         */
2521        if (diff_filespec_is_binary(two))
2522                goto free_and_return;
2523        else {
2524                /* Crazy xdl interfaces.. */
2525                xpparam_t xpp;
2526                xdemitconf_t xecfg;
2527
2528                memset(&xpp, 0, sizeof(xpp));
2529                memset(&xecfg, 0, sizeof(xecfg));
2530                xecfg.ctxlen = 1; /* at least one context line */
2531                xpp.flags = 0;
2532                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2533                              &xpp, &xecfg);
2534
2535                if (data.ws_rule & WS_BLANK_AT_EOF) {
2536                        struct emit_callback ecbdata;
2537                        int blank_at_eof;
2538
2539                        ecbdata.ws_rule = data.ws_rule;
2540                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2541                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2542
2543                        if (blank_at_eof) {
2544                                static char *err;
2545                                if (!err)
2546                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2547                                fprintf(o->file, "%s:%d: %s.\n",
2548                                        data.filename, blank_at_eof, err);
2549                                data.status = 1; /* report errors */
2550                        }
2551                }
2552        }
2553 free_and_return:
2554        diff_free_filespec_data(one);
2555        diff_free_filespec_data(two);
2556        if (data.status)
2557                DIFF_OPT_SET(o, CHECK_FAILED);
2558}
2559
2560struct diff_filespec *alloc_filespec(const char *path)
2561{
2562        int namelen = strlen(path);
2563        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2564
2565        memset(spec, 0, sizeof(*spec));
2566        spec->path = (char *)(spec + 1);
2567        memcpy(spec->path, path, namelen+1);
2568        spec->count = 1;
2569        spec->is_binary = -1;
2570        return spec;
2571}
2572
2573void free_filespec(struct diff_filespec *spec)
2574{
2575        if (!--spec->count) {
2576                diff_free_filespec_data(spec);
2577                free(spec);
2578        }
2579}
2580
2581void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2582                   int sha1_valid, unsigned short mode)
2583{
2584        if (mode) {
2585                spec->mode = canon_mode(mode);
2586                hashcpy(spec->sha1, sha1);
2587                spec->sha1_valid = sha1_valid;
2588        }
2589}
2590
2591/*
2592 * Given a name and sha1 pair, if the index tells us the file in
2593 * the work tree has that object contents, return true, so that
2594 * prepare_temp_file() does not have to inflate and extract.
2595 */
2596static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2597{
2598        struct cache_entry *ce;
2599        struct stat st;
2600        int pos, len;
2601
2602        /*
2603         * We do not read the cache ourselves here, because the
2604         * benchmark with my previous version that always reads cache
2605         * shows that it makes things worse for diff-tree comparing
2606         * two linux-2.6 kernel trees in an already checked out work
2607         * tree.  This is because most diff-tree comparisons deal with
2608         * only a small number of files, while reading the cache is
2609         * expensive for a large project, and its cost outweighs the
2610         * savings we get by not inflating the object to a temporary
2611         * file.  Practically, this code only helps when we are used
2612         * by diff-cache --cached, which does read the cache before
2613         * calling us.
2614         */
2615        if (!active_cache)
2616                return 0;
2617
2618        /* We want to avoid the working directory if our caller
2619         * doesn't need the data in a normal file, this system
2620         * is rather slow with its stat/open/mmap/close syscalls,
2621         * and the object is contained in a pack file.  The pack
2622         * is probably already open and will be faster to obtain
2623         * the data through than the working directory.  Loose
2624         * objects however would tend to be slower as they need
2625         * to be individually opened and inflated.
2626         */
2627        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2628                return 0;
2629
2630        len = strlen(name);
2631        pos = cache_name_pos(name, len);
2632        if (pos < 0)
2633                return 0;
2634        ce = active_cache[pos];
2635
2636        /*
2637         * This is not the sha1 we are looking for, or
2638         * unreusable because it is not a regular file.
2639         */
2640        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2641                return 0;
2642
2643        /*
2644         * If ce is marked as "assume unchanged", there is no
2645         * guarantee that work tree matches what we are looking for.
2646         */
2647        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2648                return 0;
2649
2650        /*
2651         * If ce matches the file in the work tree, we can reuse it.
2652         */
2653        if (ce_uptodate(ce) ||
2654            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2655                return 1;
2656
2657        return 0;
2658}
2659
2660static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2661{
2662        int len;
2663        char *data = xmalloc(100), *dirty = "";
2664
2665        /* Are we looking at the work tree? */
2666        if (s->dirty_submodule)
2667                dirty = "-dirty";
2668
2669        len = snprintf(data, 100,
2670                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2671        s->data = data;
2672        s->size = len;
2673        s->should_free = 1;
2674        if (size_only) {
2675                s->data = NULL;
2676                free(data);
2677        }
2678        return 0;
2679}
2680
2681/*
2682 * While doing rename detection and pickaxe operation, we may need to
2683 * grab the data for the blob (or file) for our own in-core comparison.
2684 * diff_filespec has data and size fields for this purpose.
2685 */
2686int diff_populate_filespec(struct diff_filespec *s, int size_only)
2687{
2688        int err = 0;
2689        if (!DIFF_FILE_VALID(s))
2690                die("internal error: asking to populate invalid file.");
2691        if (S_ISDIR(s->mode))
2692                return -1;
2693
2694        if (s->data)
2695                return 0;
2696
2697        if (size_only && 0 < s->size)
2698                return 0;
2699
2700        if (S_ISGITLINK(s->mode))
2701                return diff_populate_gitlink(s, size_only);
2702
2703        if (!s->sha1_valid ||
2704            reuse_worktree_file(s->path, s->sha1, 0)) {
2705                struct strbuf buf = STRBUF_INIT;
2706                struct stat st;
2707                int fd;
2708
2709                if (lstat(s->path, &st) < 0) {
2710                        if (errno == ENOENT) {
2711                        err_empty:
2712                                err = -1;
2713                        empty:
2714                                s->data = (char *)"";
2715                                s->size = 0;
2716                                return err;
2717                        }
2718                }
2719                s->size = xsize_t(st.st_size);
2720                if (!s->size)
2721                        goto empty;
2722                if (S_ISLNK(st.st_mode)) {
2723                        struct strbuf sb = STRBUF_INIT;
2724
2725                        if (strbuf_readlink(&sb, s->path, s->size))
2726                                goto err_empty;
2727                        s->size = sb.len;
2728                        s->data = strbuf_detach(&sb, NULL);
2729                        s->should_free = 1;
2730                        return 0;
2731                }
2732                if (size_only)
2733                        return 0;
2734                fd = open(s->path, O_RDONLY);
2735                if (fd < 0)
2736                        goto err_empty;
2737                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2738                close(fd);
2739                s->should_munmap = 1;
2740
2741                /*
2742                 * Convert from working tree format to canonical git format
2743                 */
2744                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2745                        size_t size = 0;
2746                        munmap(s->data, s->size);
2747                        s->should_munmap = 0;
2748                        s->data = strbuf_detach(&buf, &size);
2749                        s->size = size;
2750                        s->should_free = 1;
2751                }
2752        }
2753        else {
2754                enum object_type type;
2755                if (size_only) {
2756                        type = sha1_object_info(s->sha1, &s->size);
2757                        if (type < 0)
2758                                die("unable to read %s", sha1_to_hex(s->sha1));
2759                } else {
2760                        s->data = read_sha1_file(s->sha1, &type, &s->size);
2761                        if (!s->data)
2762                                die("unable to read %s", sha1_to_hex(s->sha1));
2763                        s->should_free = 1;
2764                }
2765        }
2766        return 0;
2767}
2768
2769void diff_free_filespec_blob(struct diff_filespec *s)
2770{
2771        if (s->should_free)
2772                free(s->data);
2773        else if (s->should_munmap)
2774                munmap(s->data, s->size);
2775
2776        if (s->should_free || s->should_munmap) {
2777                s->should_free = s->should_munmap = 0;
2778                s->data = NULL;
2779        }
2780}
2781
2782void diff_free_filespec_data(struct diff_filespec *s)
2783{
2784        diff_free_filespec_blob(s);
2785        free(s->cnt_data);
2786        s->cnt_data = NULL;
2787}
2788
2789static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2790                           void *blob,
2791                           unsigned long size,
2792                           const unsigned char *sha1,
2793                           int mode)
2794{
2795        int fd;
2796        struct strbuf buf = STRBUF_INIT;
2797        struct strbuf template = STRBUF_INIT;
2798        char *path_dup = xstrdup(path);
2799        const char *base = basename(path_dup);
2800
2801        /* Generate "XXXXXX_basename.ext" */
2802        strbuf_addstr(&template, "XXXXXX_");
2803        strbuf_addstr(&template, base);
2804
2805        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2806                        strlen(base) + 1);
2807        if (fd < 0)
2808                die_errno("unable to create temp-file");
2809        if (convert_to_working_tree(path,
2810                        (const char *)blob, (size_t)size, &buf)) {
2811                blob = buf.buf;
2812                size = buf.len;
2813        }
2814        if (write_in_full(fd, blob, size) != size)
2815                die_errno("unable to write temp-file");
2816        close(fd);
2817        temp->name = temp->tmp_path;
2818        strcpy(temp->hex, sha1_to_hex(sha1));
2819        temp->hex[40] = 0;
2820        sprintf(temp->mode, "%06o", mode);
2821        strbuf_release(&buf);
2822        strbuf_release(&template);
2823        free(path_dup);
2824}
2825
2826static struct diff_tempfile *prepare_temp_file(const char *name,
2827                struct diff_filespec *one)
2828{
2829        struct diff_tempfile *temp = claim_diff_tempfile();
2830
2831        if (!DIFF_FILE_VALID(one)) {
2832        not_a_valid_file:
2833                /* A '-' entry produces this for file-2, and
2834                 * a '+' entry produces this for file-1.
2835                 */
2836                temp->name = "/dev/null";
2837                strcpy(temp->hex, ".");
2838                strcpy(temp->mode, ".");
2839                return temp;
2840        }
2841
2842        if (!remove_tempfile_installed) {
2843                atexit(remove_tempfile);
2844                sigchain_push_common(remove_tempfile_on_signal);
2845                remove_tempfile_installed = 1;
2846        }
2847
2848        if (!one->sha1_valid ||
2849            reuse_worktree_file(name, one->sha1, 1)) {
2850                struct stat st;
2851                if (lstat(name, &st) < 0) {
2852                        if (errno == ENOENT)
2853                                goto not_a_valid_file;
2854                        die_errno("stat(%s)", name);
2855                }
2856                if (S_ISLNK(st.st_mode)) {
2857                        struct strbuf sb = STRBUF_INIT;
2858                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2859                                die_errno("readlink(%s)", name);
2860                        prep_temp_blob(name, temp, sb.buf, sb.len,
2861                                       (one->sha1_valid ?
2862                                        one->sha1 : null_sha1),
2863                                       (one->sha1_valid ?
2864                                        one->mode : S_IFLNK));
2865                        strbuf_release(&sb);
2866                }
2867                else {
2868                        /* we can borrow from the file in the work tree */
2869                        temp->name = name;
2870                        if (!one->sha1_valid)
2871                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2872                        else
2873                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2874                        /* Even though we may sometimes borrow the
2875                         * contents from the work tree, we always want
2876                         * one->mode.  mode is trustworthy even when
2877                         * !(one->sha1_valid), as long as
2878                         * DIFF_FILE_VALID(one).
2879                         */
2880                        sprintf(temp->mode, "%06o", one->mode);
2881                }
2882                return temp;
2883        }
2884        else {
2885                if (diff_populate_filespec(one, 0))
2886                        die("cannot read data blob for %s", one->path);
2887                prep_temp_blob(name, temp, one->data, one->size,
2888                               one->sha1, one->mode);
2889        }
2890        return temp;
2891}
2892
2893/* An external diff command takes:
2894 *
2895 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2896 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2897 *
2898 */
2899static void run_external_diff(const char *pgm,
2900                              const char *name,
2901                              const char *other,
2902                              struct diff_filespec *one,
2903                              struct diff_filespec *two,
2904                              const char *xfrm_msg,
2905                              int complete_rewrite)
2906{
2907        const char *spawn_arg[10];
2908        int retval;
2909        const char **arg = &spawn_arg[0];
2910
2911        if (one && two) {
2912                struct diff_tempfile *temp_one, *temp_two;
2913                const char *othername = (other ? other : name);
2914                temp_one = prepare_temp_file(name, one);
2915                temp_two = prepare_temp_file(othername, two);
2916                *arg++ = pgm;
2917                *arg++ = name;
2918                *arg++ = temp_one->name;
2919                *arg++ = temp_one->hex;
2920                *arg++ = temp_one->mode;
2921                *arg++ = temp_two->name;
2922                *arg++ = temp_two->hex;
2923                *arg++ = temp_two->mode;
2924                if (other) {
2925                        *arg++ = other;
2926                        *arg++ = xfrm_msg;
2927                }
2928        } else {
2929                *arg++ = pgm;
2930                *arg++ = name;
2931        }
2932        *arg = NULL;
2933        fflush(NULL);
2934        retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2935        remove_tempfile();
2936        if (retval) {
2937                fprintf(stderr, "external diff died, stopping at %s.\n", name);
2938                exit(1);
2939        }
2940}
2941
2942static int similarity_index(struct diff_filepair *p)
2943{
2944        return p->score * 100 / MAX_SCORE;
2945}
2946
2947static void fill_metainfo(struct strbuf *msg,
2948                          const char *name,
2949                          const char *other,
2950                          struct diff_filespec *one,
2951                          struct diff_filespec *two,
2952                          struct diff_options *o,
2953                          struct diff_filepair *p,
2954                          int *must_show_header,
2955                          int use_color)
2956{
2957        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2958        const char *reset = diff_get_color(use_color, DIFF_RESET);
2959        struct strbuf *msgbuf;
2960        char *line_prefix = "";
2961
2962        *must_show_header = 1;
2963        if (o->output_prefix) {
2964                msgbuf = o->output_prefix(o, o->output_prefix_data);
2965                line_prefix = msgbuf->buf;
2966        }
2967        strbuf_init(msg, PATH_MAX * 2 + 300);
2968        switch (p->status) {
2969        case DIFF_STATUS_COPIED:
2970                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2971                            line_prefix, set, similarity_index(p));
2972                strbuf_addf(msg, "%s\n%s%scopy from ",
2973                            reset,  line_prefix, set);
2974                quote_c_style(name, msg, NULL, 0);
2975                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2976                quote_c_style(other, msg, NULL, 0);
2977                strbuf_addf(msg, "%s\n", reset);
2978                break;
2979        case DIFF_STATUS_RENAMED:
2980                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2981                            line_prefix, set, similarity_index(p));
2982                strbuf_addf(msg, "%s\n%s%srename from ",
2983                            reset, line_prefix, set);
2984                quote_c_style(name, msg, NULL, 0);
2985                strbuf_addf(msg, "%s\n%s%srename to ",
2986                            reset, line_prefix, set);
2987                quote_c_style(other, msg, NULL, 0);
2988                strbuf_addf(msg, "%s\n", reset);
2989                break;
2990        case DIFF_STATUS_MODIFIED:
2991                if (p->score) {
2992                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2993                                    line_prefix,
2994                                    set, similarity_index(p), reset);
2995                        break;
2996                }
2997                /* fallthru */
2998        default:
2999                *must_show_header = 0;
3000        }
3001        if (one && two && hashcmp(one->sha1, two->sha1)) {
3002                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3003
3004                if (DIFF_OPT_TST(o, BINARY)) {
3005                        mmfile_t mf;
3006                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3007                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3008                                abbrev = 40;
3009                }
3010                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3011                            find_unique_abbrev(one->sha1, abbrev));
3012                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3013                if (one->mode == two->mode)
3014                        strbuf_addf(msg, " %06o", one->mode);
3015                strbuf_addf(msg, "%s\n", reset);
3016        }
3017}
3018
3019static void run_diff_cmd(const char *pgm,
3020                         const char *name,
3021                         const char *other,
3022                         const char *attr_path,
3023                         struct diff_filespec *one,
3024                         struct diff_filespec *two,
3025                         struct strbuf *msg,
3026                         struct diff_options *o,
3027                         struct diff_filepair *p)
3028{
3029        const char *xfrm_msg = NULL;
3030        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3031        int must_show_header = 0;
3032
3033
3034        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3035                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3036                if (drv && drv->external)
3037                        pgm = drv->external;
3038        }
3039
3040        if (msg) {
3041                /*
3042                 * don't use colors when the header is intended for an
3043                 * external diff driver
3044                 */
3045                fill_metainfo(msg, name, other, one, two, o, p,
3046                              &must_show_header,
3047                              want_color(o->use_color) && !pgm);
3048                xfrm_msg = msg->len ? msg->buf : NULL;
3049        }
3050
3051        if (pgm) {
3052                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3053                                  complete_rewrite);
3054                return;
3055        }
3056        if (one && two)
3057                builtin_diff(name, other ? other : name,
3058                             one, two, xfrm_msg, must_show_header,
3059                             o, complete_rewrite);
3060        else
3061                fprintf(o->file, "* Unmerged path %s\n", name);
3062}
3063
3064static void diff_fill_sha1_info(struct diff_filespec *one)
3065{
3066        if (DIFF_FILE_VALID(one)) {
3067                if (!one->sha1_valid) {
3068                        struct stat st;
3069                        if (one->is_stdin) {
3070                                hashcpy(one->sha1, null_sha1);
3071                                return;
3072                        }
3073                        if (lstat(one->path, &st) < 0)
3074                                die_errno("stat '%s'", one->path);
3075                        if (index_path(one->sha1, one->path, &st, 0))
3076                                die("cannot hash %s", one->path);
3077                }
3078        }
3079        else
3080                hashclr(one->sha1);
3081}
3082
3083static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3084{
3085        /* Strip the prefix but do not molest /dev/null and absolute paths */
3086        if (*namep && **namep != '/') {
3087                *namep += prefix_length;
3088                if (**namep == '/')
3089                        ++*namep;
3090        }
3091        if (*otherp && **otherp != '/') {
3092                *otherp += prefix_length;
3093                if (**otherp == '/')
3094                        ++*otherp;
3095        }
3096}
3097
3098static void run_diff(struct diff_filepair *p, struct diff_options *o)
3099{
3100        const char *pgm = external_diff();
3101        struct strbuf msg;
3102        struct diff_filespec *one = p->one;
3103        struct diff_filespec *two = p->two;
3104        const char *name;
3105        const char *other;
3106        const char *attr_path;
3107
3108        name  = p->one->path;
3109        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3110        attr_path = name;
3111        if (o->prefix_length)
3112                strip_prefix(o->prefix_length, &name, &other);
3113
3114        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3115                pgm = NULL;
3116
3117        if (DIFF_PAIR_UNMERGED(p)) {
3118                run_diff_cmd(pgm, name, NULL, attr_path,
3119                             NULL, NULL, NULL, o, p);
3120                return;
3121        }
3122
3123        diff_fill_sha1_info(one);
3124        diff_fill_sha1_info(two);
3125
3126        if (!pgm &&
3127            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3128            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3129                /*
3130                 * a filepair that changes between file and symlink
3131                 * needs to be split into deletion and creation.
3132                 */
3133                struct diff_filespec *null = alloc_filespec(two->path);
3134                run_diff_cmd(NULL, name, other, attr_path,
3135                             one, null, &msg, o, p);
3136                free(null);
3137                strbuf_release(&msg);
3138
3139                null = alloc_filespec(one->path);
3140                run_diff_cmd(NULL, name, other, attr_path,
3141                             null, two, &msg, o, p);
3142                free(null);
3143        }
3144        else
3145                run_diff_cmd(pgm, name, other, attr_path,
3146                             one, two, &msg, o, p);
3147
3148        strbuf_release(&msg);
3149}
3150
3151static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3152                         struct diffstat_t *diffstat)
3153{
3154        const char *name;
3155        const char *other;
3156
3157        if (DIFF_PAIR_UNMERGED(p)) {
3158                /* unmerged */
3159                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3160                return;
3161        }
3162
3163        name = p->one->path;
3164        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3165
3166        if (o->prefix_length)
3167                strip_prefix(o->prefix_length, &name, &other);
3168
3169        diff_fill_sha1_info(p->one);
3170        diff_fill_sha1_info(p->two);
3171
3172        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3173}
3174
3175static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3176{
3177        const char *name;
3178        const char *other;
3179        const char *attr_path;
3180
3181        if (DIFF_PAIR_UNMERGED(p)) {
3182                /* unmerged */
3183                return;
3184        }
3185
3186        name = p->one->path;
3187        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3188        attr_path = other ? other : name;
3189
3190        if (o->prefix_length)
3191                strip_prefix(o->prefix_length, &name, &other);
3192
3193        diff_fill_sha1_info(p->one);
3194        diff_fill_sha1_info(p->two);
3195
3196        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3197}
3198
3199void diff_setup(struct diff_options *options)
3200{
3201        memcpy(options, &default_diff_options, sizeof(*options));
3202
3203        options->file = stdout;
3204
3205        options->line_termination = '\n';
3206        options->break_opt = -1;
3207        options->rename_limit = -1;
3208        options->dirstat_permille = diff_dirstat_permille_default;
3209        options->context = diff_context_default;
3210        DIFF_OPT_SET(options, RENAME_EMPTY);
3211
3212        options->change = diff_change;
3213        options->add_remove = diff_addremove;
3214        options->use_color = diff_use_color_default;
3215        options->detect_rename = diff_detect_rename_default;
3216
3217        if (diff_no_prefix) {
3218                options->a_prefix = options->b_prefix = "";
3219        } else if (!diff_mnemonic_prefix) {
3220                options->a_prefix = "a/";
3221                options->b_prefix = "b/";
3222        }
3223}
3224
3225void diff_setup_done(struct diff_options *options)
3226{
3227        int count = 0;
3228
3229        if (options->output_format & DIFF_FORMAT_NAME)
3230                count++;
3231        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3232                count++;
3233        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3234                count++;
3235        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3236                count++;
3237        if (count > 1)
3238                die("--name-only, --name-status, --check and -s are mutually exclusive");
3239
3240        /*
3241         * Most of the time we can say "there are changes"
3242         * only by checking if there are changed paths, but
3243         * --ignore-whitespace* options force us to look
3244         * inside contents.
3245         */
3246
3247        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3248            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3249            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3250                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3251        else
3252                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3253
3254        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3255                options->detect_rename = DIFF_DETECT_COPY;
3256
3257        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3258                options->prefix = NULL;
3259        if (options->prefix)
3260                options->prefix_length = strlen(options->prefix);
3261        else
3262                options->prefix_length = 0;
3263
3264        if (options->output_format & (DIFF_FORMAT_NAME |
3265                                      DIFF_FORMAT_NAME_STATUS |
3266                                      DIFF_FORMAT_CHECKDIFF |
3267                                      DIFF_FORMAT_NO_OUTPUT))
3268                options->output_format &= ~(DIFF_FORMAT_RAW |
3269                                            DIFF_FORMAT_NUMSTAT |
3270                                            DIFF_FORMAT_DIFFSTAT |
3271                                            DIFF_FORMAT_SHORTSTAT |
3272                                            DIFF_FORMAT_DIRSTAT |
3273                                            DIFF_FORMAT_SUMMARY |
3274                                            DIFF_FORMAT_PATCH);
3275
3276        /*
3277         * These cases always need recursive; we do not drop caller-supplied
3278         * recursive bits for other formats here.
3279         */
3280        if (options->output_format & (DIFF_FORMAT_PATCH |
3281                                      DIFF_FORMAT_NUMSTAT |
3282                                      DIFF_FORMAT_DIFFSTAT |
3283                                      DIFF_FORMAT_SHORTSTAT |
3284                                      DIFF_FORMAT_DIRSTAT |
3285                                      DIFF_FORMAT_SUMMARY |
3286                                      DIFF_FORMAT_CHECKDIFF))
3287                DIFF_OPT_SET(options, RECURSIVE);
3288        /*
3289         * Also pickaxe would not work very well if you do not say recursive
3290         */
3291        if (options->pickaxe)
3292                DIFF_OPT_SET(options, RECURSIVE);
3293        /*
3294         * When patches are generated, submodules diffed against the work tree
3295         * must be checked for dirtiness too so it can be shown in the output
3296         */
3297        if (options->output_format & DIFF_FORMAT_PATCH)
3298                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3299
3300        if (options->detect_rename && options->rename_limit < 0)
3301                options->rename_limit = diff_rename_limit_default;
3302        if (options->setup & DIFF_SETUP_USE_CACHE) {
3303                if (!active_cache)
3304                        /* read-cache does not die even when it fails
3305                         * so it is safe for us to do this here.  Also
3306                         * it does not smudge active_cache or active_nr
3307                         * when it fails, so we do not have to worry about
3308                         * cleaning it up ourselves either.
3309                         */
3310                        read_cache();
3311        }
3312        if (options->abbrev <= 0 || 40 < options->abbrev)
3313                options->abbrev = 40; /* full */
3314
3315        /*
3316         * It does not make sense to show the first hit we happened
3317         * to have found.  It does not make sense not to return with
3318         * exit code in such a case either.
3319         */
3320        if (DIFF_OPT_TST(options, QUICK)) {
3321                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3322                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3323        }
3324}
3325
3326static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3327{
3328        char c, *eq;
3329        int len;
3330
3331        if (*arg != '-')
3332                return 0;
3333        c = *++arg;
3334        if (!c)
3335                return 0;
3336        if (c == arg_short) {
3337                c = *++arg;
3338                if (!c)
3339                        return 1;
3340                if (val && isdigit(c)) {
3341                        char *end;
3342                        int n = strtoul(arg, &end, 10);
3343                        if (*end)
3344                                return 0;
3345                        *val = n;
3346                        return 1;
3347                }
3348                return 0;
3349        }
3350        if (c != '-')
3351                return 0;
3352        arg++;
3353        eq = strchr(arg, '=');
3354        if (eq)
3355                len = eq - arg;
3356        else
3357                len = strlen(arg);
3358        if (!len || strncmp(arg, arg_long, len))
3359                return 0;
3360        if (eq) {
3361                int n;
3362                char *end;
3363                if (!isdigit(*++eq))
3364                        return 0;
3365                n = strtoul(eq, &end, 10);
3366                if (*end)
3367                        return 0;
3368                *val = n;
3369        }
3370        return 1;
3371}
3372
3373static int diff_scoreopt_parse(const char *opt);
3374
3375static inline int short_opt(char opt, const char **argv,
3376                            const char **optarg)
3377{
3378        const char *arg = argv[0];
3379        if (arg[0] != '-' || arg[1] != opt)
3380                return 0;
3381        if (arg[2] != '\0') {
3382                *optarg = arg + 2;
3383                return 1;
3384        }
3385        if (!argv[1])
3386                die("Option '%c' requires a value", opt);
3387        *optarg = argv[1];
3388        return 2;
3389}
3390
3391int parse_long_opt(const char *opt, const char **argv,
3392                   const char **optarg)
3393{
3394        const char *arg = argv[0];
3395        if (arg[0] != '-' || arg[1] != '-')
3396                return 0;
3397        arg += strlen("--");
3398        if (prefixcmp(arg, opt))
3399                return 0;
3400        arg += strlen(opt);
3401        if (*arg == '=') { /* sticked form: --option=value */
3402                *optarg = arg + 1;
3403                return 1;
3404        }
3405        if (*arg != '\0')
3406                return 0;
3407        /* separate form: --option value */
3408        if (!argv[1])
3409                die("Option '--%s' requires a value", opt);
3410        *optarg = argv[1];
3411        return 2;
3412}
3413
3414static int stat_opt(struct diff_options *options, const char **av)
3415{
3416        const char *arg = av[0];
3417        char *end;
3418        int width = options->stat_width;
3419        int name_width = options->stat_name_width;
3420        int graph_width = options->stat_graph_width;
3421        int count = options->stat_count;
3422        int argcount = 1;
3423
3424        arg += strlen("--stat");
3425        end = (char *)arg;
3426
3427        switch (*arg) {
3428        case '-':
3429                if (!prefixcmp(arg, "-width")) {
3430                        arg += strlen("-width");
3431                        if (*arg == '=')
3432                                width = strtoul(arg + 1, &end, 10);
3433                        else if (!*arg && !av[1])
3434                                die("Option '--stat-width' requires a value");
3435                        else if (!*arg) {
3436                                width = strtoul(av[1], &end, 10);
3437                                argcount = 2;
3438                        }
3439                } else if (!prefixcmp(arg, "-name-width")) {
3440                        arg += strlen("-name-width");
3441                        if (*arg == '=')
3442                                name_width = strtoul(arg + 1, &end, 10);
3443                        else if (!*arg && !av[1])
3444                                die("Option '--stat-name-width' requires a value");
3445                        else if (!*arg) {
3446                                name_width = strtoul(av[1], &end, 10);
3447                                argcount = 2;
3448                        }
3449                } else if (!prefixcmp(arg, "-graph-width")) {
3450                        arg += strlen("-graph-width");
3451                        if (*arg == '=')
3452                                graph_width = strtoul(arg + 1, &end, 10);
3453                        else if (!*arg && !av[1])
3454                                die("Option '--stat-graph-width' requires a value");
3455                        else if (!*arg) {
3456                                graph_width = strtoul(av[1], &end, 10);
3457                                argcount = 2;
3458                        }
3459                } else if (!prefixcmp(arg, "-count")) {
3460                        arg += strlen("-count");
3461                        if (*arg == '=')
3462                                count = strtoul(arg + 1, &end, 10);
3463                        else if (!*arg && !av[1])
3464                                die("Option '--stat-count' requires a value");
3465                        else if (!*arg) {
3466                                count = strtoul(av[1], &end, 10);
3467                                argcount = 2;
3468                        }
3469                }
3470                break;
3471        case '=':
3472                width = strtoul(arg+1, &end, 10);
3473                if (*end == ',')
3474                        name_width = strtoul(end+1, &end, 10);
3475                if (*end == ',')
3476                        count = strtoul(end+1, &end, 10);
3477        }
3478
3479        /* Important! This checks all the error cases! */
3480        if (*end)
3481                return 0;
3482        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3483        options->stat_name_width = name_width;
3484        options->stat_graph_width = graph_width;
3485        options->stat_width = width;
3486        options->stat_count = count;
3487        return argcount;
3488}
3489
3490static int parse_dirstat_opt(struct diff_options *options, const char *params)
3491{
3492        struct strbuf errmsg = STRBUF_INIT;
3493        if (parse_dirstat_params(options, params, &errmsg))
3494                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3495                    errmsg.buf);
3496        strbuf_release(&errmsg);
3497        /*
3498         * The caller knows a dirstat-related option is given from the command
3499         * line; allow it to say "return this_function();"
3500         */
3501        options->output_format |= DIFF_FORMAT_DIRSTAT;
3502        return 1;
3503}
3504
3505static int parse_submodule_opt(struct diff_options *options, const char *value)
3506{
3507        if (parse_submodule_params(options, value))
3508                die(_("Failed to parse --submodule option parameter: '%s'"),
3509                        value);
3510        return 1;
3511}
3512
3513int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3514{
3515        const char *arg = av[0];
3516        const char *optarg;
3517        int argcount;
3518
3519        /* Output format options */
3520        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3521                options->output_format |= DIFF_FORMAT_PATCH;
3522        else if (opt_arg(arg, 'U', "unified", &options->context))
3523                options->output_format |= DIFF_FORMAT_PATCH;
3524        else if (!strcmp(arg, "--raw"))
3525                options->output_format |= DIFF_FORMAT_RAW;
3526        else if (!strcmp(arg, "--patch-with-raw"))
3527                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3528        else if (!strcmp(arg, "--numstat"))
3529                options->output_format |= DIFF_FORMAT_NUMSTAT;
3530        else if (!strcmp(arg, "--shortstat"))
3531                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3532        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3533                return parse_dirstat_opt(options, "");
3534        else if (!prefixcmp(arg, "-X"))
3535                return parse_dirstat_opt(options, arg + 2);
3536        else if (!prefixcmp(arg, "--dirstat="))
3537                return parse_dirstat_opt(options, arg + 10);
3538        else if (!strcmp(arg, "--cumulative"))
3539                return parse_dirstat_opt(options, "cumulative");
3540        else if (!strcmp(arg, "--dirstat-by-file"))
3541                return parse_dirstat_opt(options, "files");
3542        else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3543                parse_dirstat_opt(options, "files");
3544                return parse_dirstat_opt(options, arg + 18);
3545        }
3546        else if (!strcmp(arg, "--check"))
3547                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3548        else if (!strcmp(arg, "--summary"))
3549                options->output_format |= DIFF_FORMAT_SUMMARY;
3550        else if (!strcmp(arg, "--patch-with-stat"))
3551                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3552        else if (!strcmp(arg, "--name-only"))
3553                options->output_format |= DIFF_FORMAT_NAME;
3554        else if (!strcmp(arg, "--name-status"))
3555                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3556        else if (!strcmp(arg, "-s"))
3557                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3558        else if (!prefixcmp(arg, "--stat"))
3559                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3560                return stat_opt(options, av);
3561
3562        /* renames options */
3563        else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3564                 !strcmp(arg, "--break-rewrites")) {
3565                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3566                        return error("invalid argument to -B: %s", arg+2);
3567        }
3568        else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3569                 !strcmp(arg, "--find-renames")) {
3570                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3571                        return error("invalid argument to -M: %s", arg+2);
3572                options->detect_rename = DIFF_DETECT_RENAME;
3573        }
3574        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3575                options->irreversible_delete = 1;
3576        }
3577        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3578                 !strcmp(arg, "--find-copies")) {
3579                if (options->detect_rename == DIFF_DETECT_COPY)
3580                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3581                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3582                        return error("invalid argument to -C: %s", arg+2);
3583                options->detect_rename = DIFF_DETECT_COPY;
3584        }
3585        else if (!strcmp(arg, "--no-renames"))
3586                options->detect_rename = 0;
3587        else if (!strcmp(arg, "--rename-empty"))
3588                DIFF_OPT_SET(options, RENAME_EMPTY);
3589        else if (!strcmp(arg, "--no-rename-empty"))
3590                DIFF_OPT_CLR(options, RENAME_EMPTY);
3591        else if (!strcmp(arg, "--relative"))
3592                DIFF_OPT_SET(options, RELATIVE_NAME);
3593        else if (!prefixcmp(arg, "--relative=")) {
3594                DIFF_OPT_SET(options, RELATIVE_NAME);
3595                options->prefix = arg + 11;
3596        }
3597
3598        /* xdiff options */
3599        else if (!strcmp(arg, "--minimal"))
3600                DIFF_XDL_SET(options, NEED_MINIMAL);
3601        else if (!strcmp(arg, "--no-minimal"))
3602                DIFF_XDL_CLR(options, NEED_MINIMAL);
3603        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3604                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3605        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3606                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3607        else if (!strcmp(arg, "--ignore-space-at-eol"))
3608                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3609        else if (!strcmp(arg, "--patience"))
3610                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3611        else if (!strcmp(arg, "--histogram"))
3612                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3613
3614        /* flags options */
3615        else if (!strcmp(arg, "--binary")) {
3616                options->output_format |= DIFF_FORMAT_PATCH;
3617                DIFF_OPT_SET(options, BINARY);
3618        }
3619        else if (!strcmp(arg, "--full-index"))
3620                DIFF_OPT_SET(options, FULL_INDEX);
3621        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3622                DIFF_OPT_SET(options, TEXT);
3623        else if (!strcmp(arg, "-R"))
3624                DIFF_OPT_SET(options, REVERSE_DIFF);
3625        else if (!strcmp(arg, "--find-copies-harder"))
3626                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3627        else if (!strcmp(arg, "--follow"))
3628                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3629        else if (!strcmp(arg, "--color"))
3630                options->use_color = 1;
3631        else if (!prefixcmp(arg, "--color=")) {
3632                int value = git_config_colorbool(NULL, arg+8);
3633                if (value < 0)
3634                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3635                options->use_color = value;
3636        }
3637        else if (!strcmp(arg, "--no-color"))
3638                options->use_color = 0;
3639        else if (!strcmp(arg, "--color-words")) {
3640                options->use_color = 1;
3641                options->word_diff = DIFF_WORDS_COLOR;
3642        }
3643        else if (!prefixcmp(arg, "--color-words=")) {
3644                options->use_color = 1;
3645                options->word_diff = DIFF_WORDS_COLOR;
3646                options->word_regex = arg + 14;
3647        }
3648        else if (!strcmp(arg, "--word-diff")) {
3649                if (options->word_diff == DIFF_WORDS_NONE)
3650                        options->word_diff = DIFF_WORDS_PLAIN;
3651        }
3652        else if (!prefixcmp(arg, "--word-diff=")) {
3653                const char *type = arg + 12;
3654                if (!strcmp(type, "plain"))
3655                        options->word_diff = DIFF_WORDS_PLAIN;
3656                else if (!strcmp(type, "color")) {
3657                        options->use_color = 1;
3658                        options->word_diff = DIFF_WORDS_COLOR;
3659                }
3660                else if (!strcmp(type, "porcelain"))
3661                        options->word_diff = DIFF_WORDS_PORCELAIN;
3662                else if (!strcmp(type, "none"))
3663                        options->word_diff = DIFF_WORDS_NONE;
3664                else
3665                        die("bad --word-diff argument: %s", type);
3666        }
3667        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3668                if (options->word_diff == DIFF_WORDS_NONE)
3669                        options->word_diff = DIFF_WORDS_PLAIN;
3670                options->word_regex = optarg;
3671                return argcount;
3672        }
3673        else if (!strcmp(arg, "--exit-code"))
3674                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3675        else if (!strcmp(arg, "--quiet"))
3676                DIFF_OPT_SET(options, QUICK);
3677        else if (!strcmp(arg, "--ext-diff"))
3678                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3679        else if (!strcmp(arg, "--no-ext-diff"))
3680                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3681        else if (!strcmp(arg, "--textconv"))
3682                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3683        else if (!strcmp(arg, "--no-textconv"))
3684                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3685        else if (!strcmp(arg, "--ignore-submodules")) {
3686                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3687                handle_ignore_submodules_arg(options, "all");
3688        } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3689                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3690                handle_ignore_submodules_arg(options, arg + 20);
3691        } else if (!strcmp(arg, "--submodule"))
3692                DIFF_OPT_SET(options, SUBMODULE_LOG);
3693        else if (!prefixcmp(arg, "--submodule="))
3694                return parse_submodule_opt(options, arg + 12);
3695
3696        /* misc options */
3697        else if (!strcmp(arg, "-z"))
3698                options->line_termination = 0;
3699        else if ((argcount = short_opt('l', av, &optarg))) {
3700                options->rename_limit = strtoul(optarg, NULL, 10);
3701                return argcount;
3702        }
3703        else if ((argcount = short_opt('S', av, &optarg))) {
3704                options->pickaxe = optarg;
3705                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3706                return argcount;
3707        } else if ((argcount = short_opt('G', av, &optarg))) {
3708                options->pickaxe = optarg;
3709                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3710                return argcount;
3711        }
3712        else if (!strcmp(arg, "--pickaxe-all"))
3713                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3714        else if (!strcmp(arg, "--pickaxe-regex"))
3715                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3716        else if ((argcount = short_opt('O', av, &optarg))) {
3717                options->orderfile = optarg;
3718                return argcount;
3719        }
3720        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3721                options->filter = optarg;
3722                return argcount;
3723        }
3724        else if (!strcmp(arg, "--abbrev"))
3725                options->abbrev = DEFAULT_ABBREV;
3726        else if (!prefixcmp(arg, "--abbrev=")) {
3727                options->abbrev = strtoul(arg + 9, NULL, 10);
3728                if (options->abbrev < MINIMUM_ABBREV)
3729                        options->abbrev = MINIMUM_ABBREV;
3730                else if (40 < options->abbrev)
3731                        options->abbrev = 40;
3732        }
3733        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3734                options->a_prefix = optarg;
3735                return argcount;
3736        }
3737        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3738                options->b_prefix = optarg;
3739                return argcount;
3740        }
3741        else if (!strcmp(arg, "--no-prefix"))
3742                options->a_prefix = options->b_prefix = "";
3743        else if (opt_arg(arg, '\0', "inter-hunk-context",
3744                         &options->interhunkcontext))
3745                ;
3746        else if (!strcmp(arg, "-W"))
3747                DIFF_OPT_SET(options, FUNCCONTEXT);
3748        else if (!strcmp(arg, "--function-context"))
3749                DIFF_OPT_SET(options, FUNCCONTEXT);
3750        else if (!strcmp(arg, "--no-function-context"))
3751                DIFF_OPT_CLR(options, FUNCCONTEXT);
3752        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3753                options->file = fopen(optarg, "w");
3754                if (!options->file)
3755                        die_errno("Could not open '%s'", optarg);
3756                options->close_file = 1;
3757                return argcount;
3758        } else
3759                return 0;
3760        return 1;
3761}
3762
3763int parse_rename_score(const char **cp_p)
3764{
3765        unsigned long num, scale;
3766        int ch, dot;
3767        const char *cp = *cp_p;
3768
3769        num = 0;
3770        scale = 1;
3771        dot = 0;
3772        for (;;) {
3773                ch = *cp;
3774                if ( !dot && ch == '.' ) {
3775                        scale = 1;
3776                        dot = 1;
3777                } else if ( ch == '%' ) {
3778                        scale = dot ? scale*100 : 100;
3779                        cp++;   /* % is always at the end */
3780                        break;
3781                } else if ( ch >= '0' && ch <= '9' ) {
3782                        if ( scale < 100000 ) {
3783                                scale *= 10;
3784                                num = (num*10) + (ch-'0');
3785                        }
3786                } else {
3787                        break;
3788                }
3789                cp++;
3790        }
3791        *cp_p = cp;
3792
3793        /* user says num divided by scale and we say internally that
3794         * is MAX_SCORE * num / scale.
3795         */
3796        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3797}
3798
3799static int diff_scoreopt_parse(const char *opt)
3800{
3801        int opt1, opt2, cmd;
3802
3803        if (*opt++ != '-')
3804                return -1;
3805        cmd = *opt++;
3806        if (cmd == '-') {
3807                /* convert the long-form arguments into short-form versions */
3808                if (!prefixcmp(opt, "break-rewrites")) {
3809                        opt += strlen("break-rewrites");
3810                        if (*opt == 0 || *opt++ == '=')
3811                                cmd = 'B';
3812                } else if (!prefixcmp(opt, "find-copies")) {
3813                        opt += strlen("find-copies");
3814                        if (*opt == 0 || *opt++ == '=')
3815                                cmd = 'C';
3816                } else if (!prefixcmp(opt, "find-renames")) {
3817                        opt += strlen("find-renames");
3818                        if (*opt == 0 || *opt++ == '=')
3819                                cmd = 'M';
3820                }
3821        }
3822        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3823                return -1; /* that is not a -M, -C nor -B option */
3824
3825        opt1 = parse_rename_score(&opt);
3826        if (cmd != 'B')
3827                opt2 = 0;
3828        else {
3829                if (*opt == 0)
3830                        opt2 = 0;
3831                else if (*opt != '/')
3832                        return -1; /* we expect -B80/99 or -B80 */
3833                else {
3834                        opt++;
3835                        opt2 = parse_rename_score(&opt);
3836                }
3837        }
3838        if (*opt != 0)
3839                return -1;
3840        return opt1 | (opt2 << 16);
3841}
3842
3843struct diff_queue_struct diff_queued_diff;
3844
3845void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3846{
3847        if (queue->alloc <= queue->nr) {
3848                queue->alloc = alloc_nr(queue->alloc);
3849                queue->queue = xrealloc(queue->queue,
3850                                        sizeof(dp) * queue->alloc);
3851        }
3852        queue->queue[queue->nr++] = dp;
3853}
3854
3855struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3856                                 struct diff_filespec *one,
3857                                 struct diff_filespec *two)
3858{
3859        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3860        dp->one = one;
3861        dp->two = two;
3862        if (queue)
3863                diff_q(queue, dp);
3864        return dp;
3865}
3866
3867void diff_free_filepair(struct diff_filepair *p)
3868{
3869        free_filespec(p->one);
3870        free_filespec(p->two);
3871        free(p);
3872}
3873
3874/* This is different from find_unique_abbrev() in that
3875 * it stuffs the result with dots for alignment.
3876 */
3877const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3878{
3879        int abblen;
3880        const char *abbrev;
3881        if (len == 40)
3882                return sha1_to_hex(sha1);
3883
3884        abbrev = find_unique_abbrev(sha1, len);
3885        abblen = strlen(abbrev);
3886        if (abblen < 37) {
3887                static char hex[41];
3888                if (len < abblen && abblen <= len + 2)
3889                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3890                else
3891                        sprintf(hex, "%s...", abbrev);
3892                return hex;
3893        }
3894        return sha1_to_hex(sha1);
3895}
3896
3897static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3898{
3899        int line_termination = opt->line_termination;
3900        int inter_name_termination = line_termination ? '\t' : '\0';
3901        if (opt->output_prefix) {
3902                struct strbuf *msg = NULL;
3903                msg = opt->output_prefix(opt, opt->output_prefix_data);
3904                fprintf(opt->file, "%s", msg->buf);
3905        }
3906
3907        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3908                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3909                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
3910                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3911        }
3912        if (p->score) {
3913                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3914                        inter_name_termination);
3915        } else {
3916                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3917        }
3918
3919        if (p->status == DIFF_STATUS_COPIED ||
3920            p->status == DIFF_STATUS_RENAMED) {
3921                const char *name_a, *name_b;
3922                name_a = p->one->path;
3923                name_b = p->two->path;
3924                strip_prefix(opt->prefix_length, &name_a, &name_b);
3925                write_name_quoted(name_a, opt->file, inter_name_termination);
3926                write_name_quoted(name_b, opt->file, line_termination);
3927        } else {
3928                const char *name_a, *name_b;
3929                name_a = p->one->mode ? p->one->path : p->two->path;
3930                name_b = NULL;
3931                strip_prefix(opt->prefix_length, &name_a, &name_b);
3932                write_name_quoted(name_a, opt->file, line_termination);
3933        }
3934}
3935
3936int diff_unmodified_pair(struct diff_filepair *p)
3937{
3938        /* This function is written stricter than necessary to support
3939         * the currently implemented transformers, but the idea is to
3940         * let transformers to produce diff_filepairs any way they want,
3941         * and filter and clean them up here before producing the output.
3942         */
3943        struct diff_filespec *one = p->one, *two = p->two;
3944
3945        if (DIFF_PAIR_UNMERGED(p))
3946                return 0; /* unmerged is interesting */
3947
3948        /* deletion, addition, mode or type change
3949         * and rename are all interesting.
3950         */
3951        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3952            DIFF_PAIR_MODE_CHANGED(p) ||
3953            strcmp(one->path, two->path))
3954                return 0;
3955
3956        /* both are valid and point at the same path.  that is, we are
3957         * dealing with a change.
3958         */
3959        if (one->sha1_valid && two->sha1_valid &&
3960            !hashcmp(one->sha1, two->sha1) &&
3961            !one->dirty_submodule && !two->dirty_submodule)
3962                return 1; /* no change */
3963        if (!one->sha1_valid && !two->sha1_valid)
3964                return 1; /* both look at the same file on the filesystem. */
3965        return 0;
3966}
3967
3968static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3969{
3970        if (diff_unmodified_pair(p))
3971                return;
3972
3973        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3974            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3975                return; /* no tree diffs in patch format */
3976
3977        run_diff(p, o);
3978}
3979
3980static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3981                            struct diffstat_t *diffstat)
3982{
3983        if (diff_unmodified_pair(p))
3984                return;
3985
3986        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3987            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3988                return; /* no useful stat for tree diffs */
3989
3990        run_diffstat(p, o, diffstat);
3991}
3992
3993static void diff_flush_checkdiff(struct diff_filepair *p,
3994                struct diff_options *o)
3995{
3996        if (diff_unmodified_pair(p))
3997                return;
3998
3999        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4000            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4001                return; /* nothing to check in tree diffs */
4002
4003        run_checkdiff(p, o);
4004}
4005
4006int diff_queue_is_empty(void)
4007{
4008        struct diff_queue_struct *q = &diff_queued_diff;
4009        int i;
4010        for (i = 0; i < q->nr; i++)
4011                if (!diff_unmodified_pair(q->queue[i]))
4012                        return 0;
4013        return 1;
4014}
4015
4016#if DIFF_DEBUG
4017void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4018{
4019        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4020                x, one ? one : "",
4021                s->path,
4022                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4023                s->mode,
4024                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4025        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
4026                x, one ? one : "",
4027                s->size, s->xfrm_flags);
4028}
4029
4030void diff_debug_filepair(const struct diff_filepair *p, int i)
4031{
4032        diff_debug_filespec(p->one, i, "one");
4033        diff_debug_filespec(p->two, i, "two");
4034        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4035                p->score, p->status ? p->status : '?',
4036                p->one->rename_used, p->broken_pair);
4037}
4038
4039void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4040{
4041        int i;
4042        if (msg)
4043                fprintf(stderr, "%s\n", msg);
4044        fprintf(stderr, "q->nr = %d\n", q->nr);
4045        for (i = 0; i < q->nr; i++) {
4046                struct diff_filepair *p = q->queue[i];
4047                diff_debug_filepair(p, i);
4048        }
4049}
4050#endif
4051
4052static void diff_resolve_rename_copy(void)
4053{
4054        int i;
4055        struct diff_filepair *p;
4056        struct diff_queue_struct *q = &diff_queued_diff;
4057
4058        diff_debug_queue("resolve-rename-copy", q);
4059
4060        for (i = 0; i < q->nr; i++) {
4061                p = q->queue[i];
4062                p->status = 0; /* undecided */
4063                if (DIFF_PAIR_UNMERGED(p))
4064                        p->status = DIFF_STATUS_UNMERGED;
4065                else if (!DIFF_FILE_VALID(p->one))
4066                        p->status = DIFF_STATUS_ADDED;
4067                else if (!DIFF_FILE_VALID(p->two))
4068                        p->status = DIFF_STATUS_DELETED;
4069                else if (DIFF_PAIR_TYPE_CHANGED(p))
4070                        p->status = DIFF_STATUS_TYPE_CHANGED;
4071
4072                /* from this point on, we are dealing with a pair
4073                 * whose both sides are valid and of the same type, i.e.
4074                 * either in-place edit or rename/copy edit.
4075                 */
4076                else if (DIFF_PAIR_RENAME(p)) {
4077                        /*
4078                         * A rename might have re-connected a broken
4079                         * pair up, causing the pathnames to be the
4080                         * same again. If so, that's not a rename at
4081                         * all, just a modification..
4082                         *
4083                         * Otherwise, see if this source was used for
4084                         * multiple renames, in which case we decrement
4085                         * the count, and call it a copy.
4086                         */
4087                        if (!strcmp(p->one->path, p->two->path))
4088                                p->status = DIFF_STATUS_MODIFIED;
4089                        else if (--p->one->rename_used > 0)
4090                                p->status = DIFF_STATUS_COPIED;
4091                        else
4092                                p->status = DIFF_STATUS_RENAMED;
4093                }
4094                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4095                         p->one->mode != p->two->mode ||
4096                         p->one->dirty_submodule ||
4097                         p->two->dirty_submodule ||
4098                         is_null_sha1(p->one->sha1))
4099                        p->status = DIFF_STATUS_MODIFIED;
4100                else {
4101                        /* This is a "no-change" entry and should not
4102                         * happen anymore, but prepare for broken callers.
4103                         */
4104                        error("feeding unmodified %s to diffcore",
4105                              p->one->path);
4106                        p->status = DIFF_STATUS_UNKNOWN;
4107                }
4108        }
4109        diff_debug_queue("resolve-rename-copy done", q);
4110}
4111
4112static int check_pair_status(struct diff_filepair *p)
4113{
4114        switch (p->status) {
4115        case DIFF_STATUS_UNKNOWN:
4116                return 0;
4117        case 0:
4118                die("internal error in diff-resolve-rename-copy");
4119        default:
4120                return 1;
4121        }
4122}
4123
4124static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4125{
4126        int fmt = opt->output_format;
4127
4128        if (fmt & DIFF_FORMAT_CHECKDIFF)
4129                diff_flush_checkdiff(p, opt);
4130        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4131                diff_flush_raw(p, opt);
4132        else if (fmt & DIFF_FORMAT_NAME) {
4133                const char *name_a, *name_b;
4134                name_a = p->two->path;
4135                name_b = NULL;
4136                strip_prefix(opt->prefix_length, &name_a, &name_b);
4137                write_name_quoted(name_a, opt->file, opt->line_termination);
4138        }
4139}
4140
4141static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4142{
4143        if (fs->mode)
4144                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4145        else
4146                fprintf(file, " %s ", newdelete);
4147        write_name_quoted(fs->path, file, '\n');
4148}
4149
4150
4151static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4152                const char *line_prefix)
4153{
4154        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4155                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4156                        p->two->mode, show_name ? ' ' : '\n');
4157                if (show_name) {
4158                        write_name_quoted(p->two->path, file, '\n');
4159                }
4160        }
4161}
4162
4163static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4164                        const char *line_prefix)
4165{
4166        char *names = pprint_rename(p->one->path, p->two->path);
4167
4168        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4169        free(names);
4170        show_mode_change(file, p, 0, line_prefix);
4171}
4172
4173static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4174{
4175        FILE *file = opt->file;
4176        char *line_prefix = "";
4177
4178        if (opt->output_prefix) {
4179                struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
4180                line_prefix = buf->buf;
4181        }
4182
4183        switch(p->status) {
4184        case DIFF_STATUS_DELETED:
4185                fputs(line_prefix, file);
4186                show_file_mode_name(file, "delete", p->one);
4187                break;
4188        case DIFF_STATUS_ADDED:
4189                fputs(line_prefix, file);
4190                show_file_mode_name(file, "create", p->two);
4191                break;
4192        case DIFF_STATUS_COPIED:
4193                fputs(line_prefix, file);
4194                show_rename_copy(file, "copy", p, line_prefix);
4195                break;
4196        case DIFF_STATUS_RENAMED:
4197                fputs(line_prefix, file);
4198                show_rename_copy(file, "rename", p, line_prefix);
4199                break;
4200        default:
4201                if (p->score) {
4202                        fprintf(file, "%s rewrite ", line_prefix);
4203                        write_name_quoted(p->two->path, file, ' ');
4204                        fprintf(file, "(%d%%)\n", similarity_index(p));
4205                }
4206                show_mode_change(file, p, !p->score, line_prefix);
4207                break;
4208        }
4209}
4210
4211struct patch_id_t {
4212        git_SHA_CTX *ctx;
4213        int patchlen;
4214};
4215
4216static int remove_space(char *line, int len)
4217{
4218        int i;
4219        char *dst = line;
4220        unsigned char c;
4221
4222        for (i = 0; i < len; i++)
4223                if (!isspace((c = line[i])))
4224                        *dst++ = c;
4225
4226        return dst - line;
4227}
4228
4229static void patch_id_consume(void *priv, char *line, unsigned long len)
4230{
4231        struct patch_id_t *data = priv;
4232        int new_len;
4233
4234        /* Ignore line numbers when computing the SHA1 of the patch */
4235        if (!prefixcmp(line, "@@ -"))
4236                return;
4237
4238        new_len = remove_space(line, len);
4239
4240        git_SHA1_Update(data->ctx, line, new_len);
4241        data->patchlen += new_len;
4242}
4243
4244/* returns 0 upon success, and writes result into sha1 */
4245static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4246{
4247        struct diff_queue_struct *q = &diff_queued_diff;
4248        int i;
4249        git_SHA_CTX ctx;
4250        struct patch_id_t data;
4251        char buffer[PATH_MAX * 4 + 20];
4252
4253        git_SHA1_Init(&ctx);
4254        memset(&data, 0, sizeof(struct patch_id_t));
4255        data.ctx = &ctx;
4256
4257        for (i = 0; i < q->nr; i++) {
4258                xpparam_t xpp;
4259                xdemitconf_t xecfg;
4260                mmfile_t mf1, mf2;
4261                struct diff_filepair *p = q->queue[i];
4262                int len1, len2;
4263
4264                memset(&xpp, 0, sizeof(xpp));
4265                memset(&xecfg, 0, sizeof(xecfg));
4266                if (p->status == 0)
4267                        return error("internal diff status error");
4268                if (p->status == DIFF_STATUS_UNKNOWN)
4269                        continue;
4270                if (diff_unmodified_pair(p))
4271                        continue;
4272                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4273                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4274                        continue;
4275                if (DIFF_PAIR_UNMERGED(p))
4276                        continue;
4277
4278                diff_fill_sha1_info(p->one);
4279                diff_fill_sha1_info(p->two);
4280                if (fill_mmfile(&mf1, p->one) < 0 ||
4281                                fill_mmfile(&mf2, p->two) < 0)
4282                        return error("unable to read files to diff");
4283
4284                len1 = remove_space(p->one->path, strlen(p->one->path));
4285                len2 = remove_space(p->two->path, strlen(p->two->path));
4286                if (p->one->mode == 0)
4287                        len1 = snprintf(buffer, sizeof(buffer),
4288                                        "diff--gita/%.*sb/%.*s"
4289                                        "newfilemode%06o"
4290                                        "---/dev/null"
4291                                        "+++b/%.*s",
4292                                        len1, p->one->path,
4293                                        len2, p->two->path,
4294                                        p->two->mode,
4295                                        len2, p->two->path);
4296                else if (p->two->mode == 0)
4297                        len1 = snprintf(buffer, sizeof(buffer),
4298                                        "diff--gita/%.*sb/%.*s"
4299                                        "deletedfilemode%06o"
4300                                        "---a/%.*s"
4301                                        "+++/dev/null",
4302                                        len1, p->one->path,
4303                                        len2, p->two->path,
4304                                        p->one->mode,
4305                                        len1, p->one->path);
4306                else
4307                        len1 = snprintf(buffer, sizeof(buffer),
4308                                        "diff--gita/%.*sb/%.*s"
4309                                        "---a/%.*s"
4310                                        "+++b/%.*s",
4311                                        len1, p->one->path,
4312                                        len2, p->two->path,
4313                                        len1, p->one->path,
4314                                        len2, p->two->path);
4315                git_SHA1_Update(&ctx, buffer, len1);
4316
4317                if (diff_filespec_is_binary(p->one) ||
4318                    diff_filespec_is_binary(p->two)) {
4319                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4320                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4321                        continue;
4322                }
4323
4324                xpp.flags = 0;
4325                xecfg.ctxlen = 3;
4326                xecfg.flags = 0;
4327                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4328                              &xpp, &xecfg);
4329        }
4330
4331        git_SHA1_Final(sha1, &ctx);
4332        return 0;
4333}
4334
4335int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4336{
4337        struct diff_queue_struct *q = &diff_queued_diff;
4338        int i;
4339        int result = diff_get_patch_id(options, sha1);
4340
4341        for (i = 0; i < q->nr; i++)
4342                diff_free_filepair(q->queue[i]);
4343
4344        free(q->queue);
4345        DIFF_QUEUE_CLEAR(q);
4346
4347        return result;
4348}
4349
4350static int is_summary_empty(const struct diff_queue_struct *q)
4351{
4352        int i;
4353
4354        for (i = 0; i < q->nr; i++) {
4355                const struct diff_filepair *p = q->queue[i];
4356
4357                switch (p->status) {
4358                case DIFF_STATUS_DELETED:
4359                case DIFF_STATUS_ADDED:
4360                case DIFF_STATUS_COPIED:
4361                case DIFF_STATUS_RENAMED:
4362                        return 0;
4363                default:
4364                        if (p->score)
4365                                return 0;
4366                        if (p->one->mode && p->two->mode &&
4367                            p->one->mode != p->two->mode)
4368                                return 0;
4369                        break;
4370                }
4371        }
4372        return 1;
4373}
4374
4375static const char rename_limit_warning[] =
4376"inexact rename detection was skipped due to too many files.";
4377
4378static const char degrade_cc_to_c_warning[] =
4379"only found copies from modified paths due to too many files.";
4380
4381static const char rename_limit_advice[] =
4382"you may want to set your %s variable to at least "
4383"%d and retry the command.";
4384
4385void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4386{
4387        if (degraded_cc)
4388                warning(degrade_cc_to_c_warning);
4389        else if (needed)
4390                warning(rename_limit_warning);
4391        else
4392                return;
4393        if (0 < needed && needed < 32767)
4394                warning(rename_limit_advice, varname, needed);
4395}
4396
4397void diff_flush(struct diff_options *options)
4398{
4399        struct diff_queue_struct *q = &diff_queued_diff;
4400        int i, output_format = options->output_format;
4401        int separator = 0;
4402        int dirstat_by_line = 0;
4403
4404        /*
4405         * Order: raw, stat, summary, patch
4406         * or:    name/name-status/checkdiff (other bits clear)
4407         */
4408        if (!q->nr)
4409                goto free_queue;
4410
4411        if (output_format & (DIFF_FORMAT_RAW |
4412                             DIFF_FORMAT_NAME |
4413                             DIFF_FORMAT_NAME_STATUS |
4414                             DIFF_FORMAT_CHECKDIFF)) {
4415                for (i = 0; i < q->nr; i++) {
4416                        struct diff_filepair *p = q->queue[i];
4417                        if (check_pair_status(p))
4418                                flush_one_pair(p, options);
4419                }
4420                separator++;
4421        }
4422
4423        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4424                dirstat_by_line = 1;
4425
4426        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4427            dirstat_by_line) {
4428                struct diffstat_t diffstat;
4429
4430                memset(&diffstat, 0, sizeof(struct diffstat_t));
4431                for (i = 0; i < q->nr; i++) {
4432                        struct diff_filepair *p = q->queue[i];
4433                        if (check_pair_status(p))
4434                                diff_flush_stat(p, options, &diffstat);
4435                }
4436                if (output_format & DIFF_FORMAT_NUMSTAT)
4437                        show_numstat(&diffstat, options);
4438                if (output_format & DIFF_FORMAT_DIFFSTAT)
4439                        show_stats(&diffstat, options);
4440                if (output_format & DIFF_FORMAT_SHORTSTAT)
4441                        show_shortstats(&diffstat, options);
4442                if (output_format & DIFF_FORMAT_DIRSTAT)
4443                        show_dirstat_by_line(&diffstat, options);
4444                free_diffstat_info(&diffstat);
4445                separator++;
4446        }
4447        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4448                show_dirstat(options);
4449
4450        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4451                for (i = 0; i < q->nr; i++) {
4452                        diff_summary(options, q->queue[i]);
4453                }
4454                separator++;
4455        }
4456
4457        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4458            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4459            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4460                /*
4461                 * run diff_flush_patch for the exit status. setting
4462                 * options->file to /dev/null should be safe, becaue we
4463                 * aren't supposed to produce any output anyway.
4464                 */
4465                if (options->close_file)
4466                        fclose(options->file);
4467                options->file = fopen("/dev/null", "w");
4468                if (!options->file)
4469                        die_errno("Could not open /dev/null");
4470                options->close_file = 1;
4471                for (i = 0; i < q->nr; i++) {
4472                        struct diff_filepair *p = q->queue[i];
4473                        if (check_pair_status(p))
4474                                diff_flush_patch(p, options);
4475                        if (options->found_changes)
4476                                break;
4477                }
4478        }
4479
4480        if (output_format & DIFF_FORMAT_PATCH) {
4481                if (separator) {
4482                        if (options->output_prefix) {
4483                                struct strbuf *msg = NULL;
4484                                msg = options->output_prefix(options,
4485                                        options->output_prefix_data);
4486                                fwrite(msg->buf, msg->len, 1, stdout);
4487                        }
4488                        putc(options->line_termination, options->file);
4489                        if (options->stat_sep) {
4490                                /* attach patch instead of inline */
4491                                fputs(options->stat_sep, options->file);
4492                        }
4493                }
4494
4495                for (i = 0; i < q->nr; i++) {
4496                        struct diff_filepair *p = q->queue[i];
4497                        if (check_pair_status(p))
4498                                diff_flush_patch(p, options);
4499                }
4500        }
4501
4502        if (output_format & DIFF_FORMAT_CALLBACK)
4503                options->format_callback(q, options, options->format_callback_data);
4504
4505        for (i = 0; i < q->nr; i++)
4506                diff_free_filepair(q->queue[i]);
4507free_queue:
4508        free(q->queue);
4509        DIFF_QUEUE_CLEAR(q);
4510        if (options->close_file)
4511                fclose(options->file);
4512
4513        /*
4514         * Report the content-level differences with HAS_CHANGES;
4515         * diff_addremove/diff_change does not set the bit when
4516         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4517         */
4518        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4519                if (options->found_changes)
4520                        DIFF_OPT_SET(options, HAS_CHANGES);
4521                else
4522                        DIFF_OPT_CLR(options, HAS_CHANGES);
4523        }
4524}
4525
4526static void diffcore_apply_filter(const char *filter)
4527{
4528        int i;
4529        struct diff_queue_struct *q = &diff_queued_diff;
4530        struct diff_queue_struct outq;
4531        DIFF_QUEUE_CLEAR(&outq);
4532
4533        if (!filter)
4534                return;
4535
4536        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4537                int found;
4538                for (i = found = 0; !found && i < q->nr; i++) {
4539                        struct diff_filepair *p = q->queue[i];
4540                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4541                             ((p->score &&
4542                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4543                              (!p->score &&
4544                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4545                            ((p->status != DIFF_STATUS_MODIFIED) &&
4546                             strchr(filter, p->status)))
4547                                found++;
4548                }
4549                if (found)
4550                        return;
4551
4552                /* otherwise we will clear the whole queue
4553                 * by copying the empty outq at the end of this
4554                 * function, but first clear the current entries
4555                 * in the queue.
4556                 */
4557                for (i = 0; i < q->nr; i++)
4558                        diff_free_filepair(q->queue[i]);
4559        }
4560        else {
4561                /* Only the matching ones */
4562                for (i = 0; i < q->nr; i++) {
4563                        struct diff_filepair *p = q->queue[i];
4564
4565                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4566                             ((p->score &&
4567                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4568                              (!p->score &&
4569                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4570                            ((p->status != DIFF_STATUS_MODIFIED) &&
4571                             strchr(filter, p->status)))
4572                                diff_q(&outq, p);
4573                        else
4574                                diff_free_filepair(p);
4575                }
4576        }
4577        free(q->queue);
4578        *q = outq;
4579}
4580
4581/* Check whether two filespecs with the same mode and size are identical */
4582static int diff_filespec_is_identical(struct diff_filespec *one,
4583                                      struct diff_filespec *two)
4584{
4585        if (S_ISGITLINK(one->mode))
4586                return 0;
4587        if (diff_populate_filespec(one, 0))
4588                return 0;
4589        if (diff_populate_filespec(two, 0))
4590                return 0;
4591        return !memcmp(one->data, two->data, one->size);
4592}
4593
4594static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4595{
4596        int i;
4597        struct diff_queue_struct *q = &diff_queued_diff;
4598        struct diff_queue_struct outq;
4599        DIFF_QUEUE_CLEAR(&outq);
4600
4601        for (i = 0; i < q->nr; i++) {
4602                struct diff_filepair *p = q->queue[i];
4603
4604                /*
4605                 * 1. Entries that come from stat info dirtiness
4606                 *    always have both sides (iow, not create/delete),
4607                 *    one side of the object name is unknown, with
4608                 *    the same mode and size.  Keep the ones that
4609                 *    do not match these criteria.  They have real
4610                 *    differences.
4611                 *
4612                 * 2. At this point, the file is known to be modified,
4613                 *    with the same mode and size, and the object
4614                 *    name of one side is unknown.  Need to inspect
4615                 *    the identical contents.
4616                 */
4617                if (!DIFF_FILE_VALID(p->one) || /* (1) */
4618                    !DIFF_FILE_VALID(p->two) ||
4619                    (p->one->sha1_valid && p->two->sha1_valid) ||
4620                    (p->one->mode != p->two->mode) ||
4621                    diff_populate_filespec(p->one, 1) ||
4622                    diff_populate_filespec(p->two, 1) ||
4623                    (p->one->size != p->two->size) ||
4624                    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4625                        diff_q(&outq, p);
4626                else {
4627                        /*
4628                         * The caller can subtract 1 from skip_stat_unmatch
4629                         * to determine how many paths were dirty only
4630                         * due to stat info mismatch.
4631                         */
4632                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4633                                diffopt->skip_stat_unmatch++;
4634                        diff_free_filepair(p);
4635                }
4636        }
4637        free(q->queue);
4638        *q = outq;
4639}
4640
4641static int diffnamecmp(const void *a_, const void *b_)
4642{
4643        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4644        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4645        const char *name_a, *name_b;
4646
4647        name_a = a->one ? a->one->path : a->two->path;
4648        name_b = b->one ? b->one->path : b->two->path;
4649        return strcmp(name_a, name_b);
4650}
4651
4652void diffcore_fix_diff_index(struct diff_options *options)
4653{
4654        struct diff_queue_struct *q = &diff_queued_diff;
4655        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4656}
4657
4658void diffcore_std(struct diff_options *options)
4659{
4660        if (options->skip_stat_unmatch)
4661                diffcore_skip_stat_unmatch(options);
4662        if (!options->found_follow) {
4663                /* See try_to_follow_renames() in tree-diff.c */
4664                if (options->break_opt != -1)
4665                        diffcore_break(options->break_opt);
4666                if (options->detect_rename)
4667                        diffcore_rename(options);
4668                if (options->break_opt != -1)
4669                        diffcore_merge_broken();
4670        }
4671        if (options->pickaxe)
4672                diffcore_pickaxe(options);
4673        if (options->orderfile)
4674                diffcore_order(options->orderfile);
4675        if (!options->found_follow)
4676                /* See try_to_follow_renames() in tree-diff.c */
4677                diff_resolve_rename_copy();
4678        diffcore_apply_filter(options->filter);
4679
4680        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4681                DIFF_OPT_SET(options, HAS_CHANGES);
4682        else
4683                DIFF_OPT_CLR(options, HAS_CHANGES);
4684
4685        options->found_follow = 0;
4686}
4687
4688int diff_result_code(struct diff_options *opt, int status)
4689{
4690        int result = 0;
4691
4692        diff_warn_rename_limit("diff.renamelimit",
4693                               opt->needed_rename_limit,
4694                               opt->degraded_cc_to_c);
4695        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4696            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4697                return status;
4698        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4699            DIFF_OPT_TST(opt, HAS_CHANGES))
4700                result |= 01;
4701        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4702            DIFF_OPT_TST(opt, CHECK_FAILED))
4703                result |= 02;
4704        return result;
4705}
4706
4707int diff_can_quit_early(struct diff_options *opt)
4708{
4709        return (DIFF_OPT_TST(opt, QUICK) &&
4710                !opt->filter &&
4711                DIFF_OPT_TST(opt, HAS_CHANGES));
4712}
4713
4714/*
4715 * Shall changes to this submodule be ignored?
4716 *
4717 * Submodule changes can be configured to be ignored separately for each path,
4718 * but that configuration can be overridden from the command line.
4719 */
4720static int is_submodule_ignored(const char *path, struct diff_options *options)
4721{
4722        int ignored = 0;
4723        unsigned orig_flags = options->flags;
4724        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4725                set_diffopt_flags_from_submodule_config(options, path);
4726        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4727                ignored = 1;
4728        options->flags = orig_flags;
4729        return ignored;
4730}
4731
4732void diff_addremove(struct diff_options *options,
4733                    int addremove, unsigned mode,
4734                    const unsigned char *sha1,
4735                    int sha1_valid,
4736                    const char *concatpath, unsigned dirty_submodule)
4737{
4738        struct diff_filespec *one, *two;
4739
4740        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4741                return;
4742
4743        /* This may look odd, but it is a preparation for
4744         * feeding "there are unchanged files which should
4745         * not produce diffs, but when you are doing copy
4746         * detection you would need them, so here they are"
4747         * entries to the diff-core.  They will be prefixed
4748         * with something like '=' or '*' (I haven't decided
4749         * which but should not make any difference).
4750         * Feeding the same new and old to diff_change()
4751         * also has the same effect.
4752         * Before the final output happens, they are pruned after
4753         * merged into rename/copy pairs as appropriate.
4754         */
4755        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4756                addremove = (addremove == '+' ? '-' :
4757                             addremove == '-' ? '+' : addremove);
4758
4759        if (options->prefix &&
4760            strncmp(concatpath, options->prefix, options->prefix_length))
4761                return;
4762
4763        one = alloc_filespec(concatpath);
4764        two = alloc_filespec(concatpath);
4765
4766        if (addremove != '+')
4767                fill_filespec(one, sha1, sha1_valid, mode);
4768        if (addremove != '-') {
4769                fill_filespec(two, sha1, sha1_valid, mode);
4770                two->dirty_submodule = dirty_submodule;
4771        }
4772
4773        diff_queue(&diff_queued_diff, one, two);
4774        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4775                DIFF_OPT_SET(options, HAS_CHANGES);
4776}
4777
4778void diff_change(struct diff_options *options,
4779                 unsigned old_mode, unsigned new_mode,
4780                 const unsigned char *old_sha1,
4781                 const unsigned char *new_sha1,
4782                 int old_sha1_valid, int new_sha1_valid,
4783                 const char *concatpath,
4784                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4785{
4786        struct diff_filespec *one, *two;
4787
4788        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4789            is_submodule_ignored(concatpath, options))
4790                return;
4791
4792        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4793                unsigned tmp;
4794                const unsigned char *tmp_c;
4795                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4796                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4797                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4798                        new_sha1_valid = tmp;
4799                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4800                        new_dirty_submodule = tmp;
4801        }
4802
4803        if (options->prefix &&
4804            strncmp(concatpath, options->prefix, options->prefix_length))
4805                return;
4806
4807        one = alloc_filespec(concatpath);
4808        two = alloc_filespec(concatpath);
4809        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4810        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4811        one->dirty_submodule = old_dirty_submodule;
4812        two->dirty_submodule = new_dirty_submodule;
4813
4814        diff_queue(&diff_queued_diff, one, two);
4815        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4816                DIFF_OPT_SET(options, HAS_CHANGES);
4817}
4818
4819struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4820{
4821        struct diff_filepair *pair;
4822        struct diff_filespec *one, *two;
4823
4824        if (options->prefix &&
4825            strncmp(path, options->prefix, options->prefix_length))
4826                return NULL;
4827
4828        one = alloc_filespec(path);
4829        two = alloc_filespec(path);
4830        pair = diff_queue(&diff_queued_diff, one, two);
4831        pair->is_unmerged = 1;
4832        return pair;
4833}
4834
4835static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4836                size_t *outsize)
4837{
4838        struct diff_tempfile *temp;
4839        const char *argv[3];
4840        const char **arg = argv;
4841        struct child_process child;
4842        struct strbuf buf = STRBUF_INIT;
4843        int err = 0;
4844
4845        temp = prepare_temp_file(spec->path, spec);
4846        *arg++ = pgm;
4847        *arg++ = temp->name;
4848        *arg = NULL;
4849
4850        memset(&child, 0, sizeof(child));
4851        child.use_shell = 1;
4852        child.argv = argv;
4853        child.out = -1;
4854        if (start_command(&child)) {
4855                remove_tempfile();
4856                return NULL;
4857        }
4858
4859        if (strbuf_read(&buf, child.out, 0) < 0)
4860                err = error("error reading from textconv command '%s'", pgm);
4861        close(child.out);
4862
4863        if (finish_command(&child) || err) {
4864                strbuf_release(&buf);
4865                remove_tempfile();
4866                return NULL;
4867        }
4868        remove_tempfile();
4869
4870        return strbuf_detach(&buf, outsize);
4871}
4872
4873size_t fill_textconv(struct userdiff_driver *driver,
4874                     struct diff_filespec *df,
4875                     char **outbuf)
4876{
4877        size_t size;
4878
4879        if (!driver || !driver->textconv) {
4880                if (!DIFF_FILE_VALID(df)) {
4881                        *outbuf = "";
4882                        return 0;
4883                }
4884                if (diff_populate_filespec(df, 0))
4885                        die("unable to read files to diff");
4886                *outbuf = df->data;
4887                return df->size;
4888        }
4889
4890        if (driver->textconv_cache && df->sha1_valid) {
4891                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4892                                          &size);
4893                if (*outbuf)
4894                        return size;
4895        }
4896
4897        *outbuf = run_textconv(driver->textconv, df, &size);
4898        if (!*outbuf)
4899                die("unable to read files to diff");
4900
4901        if (driver->textconv_cache && df->sha1_valid) {
4902                /* ignore errors, as we might be in a readonly repository */
4903                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4904                                size);
4905                /*
4906                 * we could save up changes and flush them all at the end,
4907                 * but we would need an extra call after all diffing is done.
4908                 * Since generating a cache entry is the slow path anyway,
4909                 * this extra overhead probably isn't a big deal.
4910                 */
4911                notes_cache_write(driver->textconv_cache);
4912        }
4913
4914        return size;
4915}
4916
4917void setup_diff_pager(struct diff_options *opt)
4918{
4919        /*
4920         * If the user asked for our exit code, then either they want --quiet
4921         * or --exit-code. We should definitely not bother with a pager in the
4922         * former case, as we will generate no output. Since we still properly
4923         * report our exit code even when a pager is run, we _could_ run a
4924         * pager with --exit-code. But since we have not done so historically,
4925         * and because it is easy to find people oneline advising "git diff
4926         * --exit-code" in hooks and other scripts, we do not do so.
4927         */
4928        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4929            check_pager_config("diff") != 0)
4930                setup_pager();
4931}