diff.con commit Minor update to how-to maintain git (d4e5896)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18
  19#ifdef NO_FAST_WORKING_DIRECTORY
  20#define FAST_WORKING_DIRECTORY 0
  21#else
  22#define FAST_WORKING_DIRECTORY 1
  23#endif
  24
  25static int diff_detect_rename_default;
  26static int diff_rename_limit_default = 400;
  27static int diff_suppress_blank_empty;
  28int diff_use_color_default = -1;
  29static const char *diff_word_regex_cfg;
  30static const char *external_diff_cmd_cfg;
  31int diff_auto_refresh_index = 1;
  32static int diff_mnemonic_prefix;
  33static int diff_no_prefix;
  34static int diff_dirstat_permille_default = 30;
  35static struct diff_options default_diff_options;
  36
  37static char diff_colors[][COLOR_MAXLEN] = {
  38        GIT_COLOR_RESET,
  39        GIT_COLOR_NORMAL,       /* PLAIN */
  40        GIT_COLOR_BOLD,         /* METAINFO */
  41        GIT_COLOR_CYAN,         /* FRAGINFO */
  42        GIT_COLOR_RED,          /* OLD */
  43        GIT_COLOR_GREEN,        /* NEW */
  44        GIT_COLOR_YELLOW,       /* COMMIT */
  45        GIT_COLOR_BG_RED,       /* WHITESPACE */
  46        GIT_COLOR_NORMAL,       /* FUNCINFO */
  47};
  48
  49static int parse_diff_color_slot(const char *var, int ofs)
  50{
  51        if (!strcasecmp(var+ofs, "plain"))
  52                return DIFF_PLAIN;
  53        if (!strcasecmp(var+ofs, "meta"))
  54                return DIFF_METAINFO;
  55        if (!strcasecmp(var+ofs, "frag"))
  56                return DIFF_FRAGINFO;
  57        if (!strcasecmp(var+ofs, "old"))
  58                return DIFF_FILE_OLD;
  59        if (!strcasecmp(var+ofs, "new"))
  60                return DIFF_FILE_NEW;
  61        if (!strcasecmp(var+ofs, "commit"))
  62                return DIFF_COMMIT;
  63        if (!strcasecmp(var+ofs, "whitespace"))
  64                return DIFF_WHITESPACE;
  65        if (!strcasecmp(var+ofs, "func"))
  66                return DIFF_FUNCINFO;
  67        return -1;
  68}
  69
  70static int parse_dirstat_params(struct diff_options *options, const char *params,
  71                                struct strbuf *errmsg)
  72{
  73        const char *p = params;
  74        int p_len, ret = 0;
  75
  76        while (*p) {
  77                p_len = strchrnul(p, ',') - p;
  78                if (!memcmp(p, "changes", p_len)) {
  79                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  80                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  81                } else if (!memcmp(p, "lines", p_len)) {
  82                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  83                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  84                } else if (!memcmp(p, "files", p_len)) {
  85                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  86                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  87                } else if (!memcmp(p, "noncumulative", p_len)) {
  88                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  89                } else if (!memcmp(p, "cumulative", p_len)) {
  90                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  91                } else if (isdigit(*p)) {
  92                        char *end;
  93                        int permille = strtoul(p, &end, 10) * 10;
  94                        if (*end == '.' && isdigit(*++end)) {
  95                                /* only use first digit */
  96                                permille += *end - '0';
  97                                /* .. and ignore any further digits */
  98                                while (isdigit(*++end))
  99                                        ; /* nothing */
 100                        }
 101                        if (end - p == p_len)
 102                                options->dirstat_permille = permille;
 103                        else {
 104                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%.*s'\n"),
 105                                            p_len, p);
 106                                ret++;
 107                        }
 108                } else {
 109                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%.*s'\n"),
 110                                    p_len, p);
 111                        ret++;
 112                }
 113
 114                p += p_len;
 115
 116                if (*p)
 117                        p++; /* more parameters, swallow separator */
 118        }
 119        return ret;
 120}
 121
 122static int git_config_rename(const char *var, const char *value)
 123{
 124        if (!value)
 125                return DIFF_DETECT_RENAME;
 126        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 127                return  DIFF_DETECT_COPY;
 128        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 129}
 130
 131/*
 132 * These are to give UI layer defaults.
 133 * The core-level commands such as git-diff-files should
 134 * never be affected by the setting of diff.renames
 135 * the user happens to have in the configuration file.
 136 */
 137int git_diff_ui_config(const char *var, const char *value, void *cb)
 138{
 139        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 140                diff_use_color_default = git_config_colorbool(var, value);
 141                return 0;
 142        }
 143        if (!strcmp(var, "diff.renames")) {
 144                diff_detect_rename_default = git_config_rename(var, value);
 145                return 0;
 146        }
 147        if (!strcmp(var, "diff.autorefreshindex")) {
 148                diff_auto_refresh_index = git_config_bool(var, value);
 149                return 0;
 150        }
 151        if (!strcmp(var, "diff.mnemonicprefix")) {
 152                diff_mnemonic_prefix = git_config_bool(var, value);
 153                return 0;
 154        }
 155        if (!strcmp(var, "diff.noprefix")) {
 156                diff_no_prefix = git_config_bool(var, value);
 157                return 0;
 158        }
 159        if (!strcmp(var, "diff.external"))
 160                return git_config_string(&external_diff_cmd_cfg, var, value);
 161        if (!strcmp(var, "diff.wordregex"))
 162                return git_config_string(&diff_word_regex_cfg, var, value);
 163
 164        if (!strcmp(var, "diff.ignoresubmodules"))
 165                handle_ignore_submodules_arg(&default_diff_options, value);
 166
 167        if (git_color_config(var, value, cb) < 0)
 168                return -1;
 169
 170        return git_diff_basic_config(var, value, cb);
 171}
 172
 173int git_diff_basic_config(const char *var, const char *value, void *cb)
 174{
 175        if (!strcmp(var, "diff.renamelimit")) {
 176                diff_rename_limit_default = git_config_int(var, value);
 177                return 0;
 178        }
 179
 180        switch (userdiff_config(var, value)) {
 181                case 0: break;
 182                case -1: return -1;
 183                default: return 0;
 184        }
 185
 186        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 187                int slot = parse_diff_color_slot(var, 11);
 188                if (slot < 0)
 189                        return 0;
 190                if (!value)
 191                        return config_error_nonbool(var);
 192                color_parse(value, var, diff_colors[slot]);
 193                return 0;
 194        }
 195
 196        /* like GNU diff's --suppress-blank-empty option  */
 197        if (!strcmp(var, "diff.suppressblankempty") ||
 198                        /* for backwards compatibility */
 199                        !strcmp(var, "diff.suppress-blank-empty")) {
 200                diff_suppress_blank_empty = git_config_bool(var, value);
 201                return 0;
 202        }
 203
 204        if (!strcmp(var, "diff.dirstat")) {
 205                struct strbuf errmsg = STRBUF_INIT;
 206                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 207                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 208                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 209                                errmsg.buf);
 210                strbuf_release(&errmsg);
 211                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 212                return 0;
 213        }
 214
 215        if (!prefixcmp(var, "submodule."))
 216                return parse_submodule_config_option(var, value);
 217
 218        return git_default_config(var, value, cb);
 219}
 220
 221static char *quote_two(const char *one, const char *two)
 222{
 223        int need_one = quote_c_style(one, NULL, NULL, 1);
 224        int need_two = quote_c_style(two, NULL, NULL, 1);
 225        struct strbuf res = STRBUF_INIT;
 226
 227        if (need_one + need_two) {
 228                strbuf_addch(&res, '"');
 229                quote_c_style(one, &res, NULL, 1);
 230                quote_c_style(two, &res, NULL, 1);
 231                strbuf_addch(&res, '"');
 232        } else {
 233                strbuf_addstr(&res, one);
 234                strbuf_addstr(&res, two);
 235        }
 236        return strbuf_detach(&res, NULL);
 237}
 238
 239static const char *external_diff(void)
 240{
 241        static const char *external_diff_cmd = NULL;
 242        static int done_preparing = 0;
 243
 244        if (done_preparing)
 245                return external_diff_cmd;
 246        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 247        if (!external_diff_cmd)
 248                external_diff_cmd = external_diff_cmd_cfg;
 249        done_preparing = 1;
 250        return external_diff_cmd;
 251}
 252
 253static struct diff_tempfile {
 254        const char *name; /* filename external diff should read from */
 255        char hex[41];
 256        char mode[10];
 257        char tmp_path[PATH_MAX];
 258} diff_temp[2];
 259
 260typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 261
 262struct emit_callback {
 263        int color_diff;
 264        unsigned ws_rule;
 265        int blank_at_eof_in_preimage;
 266        int blank_at_eof_in_postimage;
 267        int lno_in_preimage;
 268        int lno_in_postimage;
 269        sane_truncate_fn truncate;
 270        const char **label_path;
 271        struct diff_words_data *diff_words;
 272        struct diff_options *opt;
 273        int *found_changesp;
 274        struct strbuf *header;
 275};
 276
 277static int count_lines(const char *data, int size)
 278{
 279        int count, ch, completely_empty = 1, nl_just_seen = 0;
 280        count = 0;
 281        while (0 < size--) {
 282                ch = *data++;
 283                if (ch == '\n') {
 284                        count++;
 285                        nl_just_seen = 1;
 286                        completely_empty = 0;
 287                }
 288                else {
 289                        nl_just_seen = 0;
 290                        completely_empty = 0;
 291                }
 292        }
 293        if (completely_empty)
 294                return 0;
 295        if (!nl_just_seen)
 296                count++; /* no trailing newline */
 297        return count;
 298}
 299
 300static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 301{
 302        if (!DIFF_FILE_VALID(one)) {
 303                mf->ptr = (char *)""; /* does not matter */
 304                mf->size = 0;
 305                return 0;
 306        }
 307        else if (diff_populate_filespec(one, 0))
 308                return -1;
 309
 310        mf->ptr = one->data;
 311        mf->size = one->size;
 312        return 0;
 313}
 314
 315/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 316static unsigned long diff_filespec_size(struct diff_filespec *one)
 317{
 318        if (!DIFF_FILE_VALID(one))
 319                return 0;
 320        diff_populate_filespec(one, 1);
 321        return one->size;
 322}
 323
 324static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 325{
 326        char *ptr = mf->ptr;
 327        long size = mf->size;
 328        int cnt = 0;
 329
 330        if (!size)
 331                return cnt;
 332        ptr += size - 1; /* pointing at the very end */
 333        if (*ptr != '\n')
 334                ; /* incomplete line */
 335        else
 336                ptr--; /* skip the last LF */
 337        while (mf->ptr < ptr) {
 338                char *prev_eol;
 339                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 340                        if (*prev_eol == '\n')
 341                                break;
 342                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 343                        break;
 344                cnt++;
 345                ptr = prev_eol - 1;
 346        }
 347        return cnt;
 348}
 349
 350static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 351                               struct emit_callback *ecbdata)
 352{
 353        int l1, l2, at;
 354        unsigned ws_rule = ecbdata->ws_rule;
 355        l1 = count_trailing_blank(mf1, ws_rule);
 356        l2 = count_trailing_blank(mf2, ws_rule);
 357        if (l2 <= l1) {
 358                ecbdata->blank_at_eof_in_preimage = 0;
 359                ecbdata->blank_at_eof_in_postimage = 0;
 360                return;
 361        }
 362        at = count_lines(mf1->ptr, mf1->size);
 363        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 364
 365        at = count_lines(mf2->ptr, mf2->size);
 366        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 367}
 368
 369static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 370                        int first, const char *line, int len)
 371{
 372        int has_trailing_newline, has_trailing_carriage_return;
 373        int nofirst;
 374        FILE *file = o->file;
 375
 376        if (o->output_prefix) {
 377                struct strbuf *msg = NULL;
 378                msg = o->output_prefix(o, o->output_prefix_data);
 379                assert(msg);
 380                fwrite(msg->buf, msg->len, 1, file);
 381        }
 382
 383        if (len == 0) {
 384                has_trailing_newline = (first == '\n');
 385                has_trailing_carriage_return = (!has_trailing_newline &&
 386                                                (first == '\r'));
 387                nofirst = has_trailing_newline || has_trailing_carriage_return;
 388        } else {
 389                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 390                if (has_trailing_newline)
 391                        len--;
 392                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 393                if (has_trailing_carriage_return)
 394                        len--;
 395                nofirst = 0;
 396        }
 397
 398        if (len || !nofirst) {
 399                fputs(set, file);
 400                if (!nofirst)
 401                        fputc(first, file);
 402                fwrite(line, len, 1, file);
 403                fputs(reset, file);
 404        }
 405        if (has_trailing_carriage_return)
 406                fputc('\r', file);
 407        if (has_trailing_newline)
 408                fputc('\n', file);
 409}
 410
 411static void emit_line(struct diff_options *o, const char *set, const char *reset,
 412                      const char *line, int len)
 413{
 414        emit_line_0(o, set, reset, line[0], line+1, len-1);
 415}
 416
 417static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 418{
 419        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 420              ecbdata->blank_at_eof_in_preimage &&
 421              ecbdata->blank_at_eof_in_postimage &&
 422              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 423              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 424                return 0;
 425        return ws_blank_line(line, len, ecbdata->ws_rule);
 426}
 427
 428static void emit_add_line(const char *reset,
 429                          struct emit_callback *ecbdata,
 430                          const char *line, int len)
 431{
 432        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 433        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 434
 435        if (!*ws)
 436                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 437        else if (new_blank_line_at_eof(ecbdata, line, len))
 438                /* Blank line at EOF - paint '+' as well */
 439                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 440        else {
 441                /* Emit just the prefix, then the rest. */
 442                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 443                ws_check_emit(line, len, ecbdata->ws_rule,
 444                              ecbdata->opt->file, set, reset, ws);
 445        }
 446}
 447
 448static void emit_hunk_header(struct emit_callback *ecbdata,
 449                             const char *line, int len)
 450{
 451        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 452        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 453        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 454        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 455        static const char atat[2] = { '@', '@' };
 456        const char *cp, *ep;
 457        struct strbuf msgbuf = STRBUF_INIT;
 458        int org_len = len;
 459        int i = 1;
 460
 461        /*
 462         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 463         * it always is at least 10 bytes long.
 464         */
 465        if (len < 10 ||
 466            memcmp(line, atat, 2) ||
 467            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 468                emit_line(ecbdata->opt, plain, reset, line, len);
 469                return;
 470        }
 471        ep += 2; /* skip over @@ */
 472
 473        /* The hunk header in fraginfo color */
 474        strbuf_add(&msgbuf, frag, strlen(frag));
 475        strbuf_add(&msgbuf, line, ep - line);
 476        strbuf_add(&msgbuf, reset, strlen(reset));
 477
 478        /*
 479         * trailing "\r\n"
 480         */
 481        for ( ; i < 3; i++)
 482                if (line[len - i] == '\r' || line[len - i] == '\n')
 483                        len--;
 484
 485        /* blank before the func header */
 486        for (cp = ep; ep - line < len; ep++)
 487                if (*ep != ' ' && *ep != '\t')
 488                        break;
 489        if (ep != cp) {
 490                strbuf_add(&msgbuf, plain, strlen(plain));
 491                strbuf_add(&msgbuf, cp, ep - cp);
 492                strbuf_add(&msgbuf, reset, strlen(reset));
 493        }
 494
 495        if (ep < line + len) {
 496                strbuf_add(&msgbuf, func, strlen(func));
 497                strbuf_add(&msgbuf, ep, line + len - ep);
 498                strbuf_add(&msgbuf, reset, strlen(reset));
 499        }
 500
 501        strbuf_add(&msgbuf, line + len, org_len - len);
 502        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 503        strbuf_release(&msgbuf);
 504}
 505
 506static struct diff_tempfile *claim_diff_tempfile(void) {
 507        int i;
 508        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 509                if (!diff_temp[i].name)
 510                        return diff_temp + i;
 511        die("BUG: diff is failing to clean up its tempfiles");
 512}
 513
 514static int remove_tempfile_installed;
 515
 516static void remove_tempfile(void)
 517{
 518        int i;
 519        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 520                if (diff_temp[i].name == diff_temp[i].tmp_path)
 521                        unlink_or_warn(diff_temp[i].name);
 522                diff_temp[i].name = NULL;
 523        }
 524}
 525
 526static void remove_tempfile_on_signal(int signo)
 527{
 528        remove_tempfile();
 529        sigchain_pop(signo);
 530        raise(signo);
 531}
 532
 533static void print_line_count(FILE *file, int count)
 534{
 535        switch (count) {
 536        case 0:
 537                fprintf(file, "0,0");
 538                break;
 539        case 1:
 540                fprintf(file, "1");
 541                break;
 542        default:
 543                fprintf(file, "1,%d", count);
 544                break;
 545        }
 546}
 547
 548static void emit_rewrite_lines(struct emit_callback *ecb,
 549                               int prefix, const char *data, int size)
 550{
 551        const char *endp = NULL;
 552        static const char *nneof = " No newline at end of file\n";
 553        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 554        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 555
 556        while (0 < size) {
 557                int len;
 558
 559                endp = memchr(data, '\n', size);
 560                len = endp ? (endp - data + 1) : size;
 561                if (prefix != '+') {
 562                        ecb->lno_in_preimage++;
 563                        emit_line_0(ecb->opt, old, reset, '-',
 564                                    data, len);
 565                } else {
 566                        ecb->lno_in_postimage++;
 567                        emit_add_line(reset, ecb, data, len);
 568                }
 569                size -= len;
 570                data += len;
 571        }
 572        if (!endp) {
 573                const char *plain = diff_get_color(ecb->color_diff,
 574                                                   DIFF_PLAIN);
 575                emit_line_0(ecb->opt, plain, reset, '\\',
 576                            nneof, strlen(nneof));
 577        }
 578}
 579
 580static void emit_rewrite_diff(const char *name_a,
 581                              const char *name_b,
 582                              struct diff_filespec *one,
 583                              struct diff_filespec *two,
 584                              struct userdiff_driver *textconv_one,
 585                              struct userdiff_driver *textconv_two,
 586                              struct diff_options *o)
 587{
 588        int lc_a, lc_b;
 589        const char *name_a_tab, *name_b_tab;
 590        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 591        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 592        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 593        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 594        const char *a_prefix, *b_prefix;
 595        char *data_one, *data_two;
 596        size_t size_one, size_two;
 597        struct emit_callback ecbdata;
 598        char *line_prefix = "";
 599        struct strbuf *msgbuf;
 600
 601        if (o && o->output_prefix) {
 602                msgbuf = o->output_prefix(o, o->output_prefix_data);
 603                line_prefix = msgbuf->buf;
 604        }
 605
 606        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 607                a_prefix = o->b_prefix;
 608                b_prefix = o->a_prefix;
 609        } else {
 610                a_prefix = o->a_prefix;
 611                b_prefix = o->b_prefix;
 612        }
 613
 614        name_a += (*name_a == '/');
 615        name_b += (*name_b == '/');
 616        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 617        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 618
 619        strbuf_reset(&a_name);
 620        strbuf_reset(&b_name);
 621        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 622        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 623
 624        size_one = fill_textconv(textconv_one, one, &data_one);
 625        size_two = fill_textconv(textconv_two, two, &data_two);
 626
 627        memset(&ecbdata, 0, sizeof(ecbdata));
 628        ecbdata.color_diff = want_color(o->use_color);
 629        ecbdata.found_changesp = &o->found_changes;
 630        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 631        ecbdata.opt = o;
 632        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 633                mmfile_t mf1, mf2;
 634                mf1.ptr = (char *)data_one;
 635                mf2.ptr = (char *)data_two;
 636                mf1.size = size_one;
 637                mf2.size = size_two;
 638                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 639        }
 640        ecbdata.lno_in_preimage = 1;
 641        ecbdata.lno_in_postimage = 1;
 642
 643        lc_a = count_lines(data_one, size_one);
 644        lc_b = count_lines(data_two, size_two);
 645        fprintf(o->file,
 646                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 647                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 648                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 649                line_prefix, fraginfo);
 650        if (!o->irreversible_delete)
 651                print_line_count(o->file, lc_a);
 652        else
 653                fprintf(o->file, "?,?");
 654        fprintf(o->file, " +");
 655        print_line_count(o->file, lc_b);
 656        fprintf(o->file, " @@%s\n", reset);
 657        if (lc_a && !o->irreversible_delete)
 658                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 659        if (lc_b)
 660                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 661        if (textconv_one)
 662                free((char *)data_one);
 663        if (textconv_two)
 664                free((char *)data_two);
 665}
 666
 667struct diff_words_buffer {
 668        mmfile_t text;
 669        long alloc;
 670        struct diff_words_orig {
 671                const char *begin, *end;
 672        } *orig;
 673        int orig_nr, orig_alloc;
 674};
 675
 676static void diff_words_append(char *line, unsigned long len,
 677                struct diff_words_buffer *buffer)
 678{
 679        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 680        line++;
 681        len--;
 682        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 683        buffer->text.size += len;
 684        buffer->text.ptr[buffer->text.size] = '\0';
 685}
 686
 687struct diff_words_style_elem {
 688        const char *prefix;
 689        const char *suffix;
 690        const char *color; /* NULL; filled in by the setup code if
 691                            * color is enabled */
 692};
 693
 694struct diff_words_style {
 695        enum diff_words_type type;
 696        struct diff_words_style_elem new, old, ctx;
 697        const char *newline;
 698};
 699
 700static struct diff_words_style diff_words_styles[] = {
 701        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 702        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 703        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 704};
 705
 706struct diff_words_data {
 707        struct diff_words_buffer minus, plus;
 708        const char *current_plus;
 709        int last_minus;
 710        struct diff_options *opt;
 711        regex_t *word_regex;
 712        enum diff_words_type type;
 713        struct diff_words_style *style;
 714};
 715
 716static int fn_out_diff_words_write_helper(FILE *fp,
 717                                          struct diff_words_style_elem *st_el,
 718                                          const char *newline,
 719                                          size_t count, const char *buf,
 720                                          const char *line_prefix)
 721{
 722        int print = 0;
 723
 724        while (count) {
 725                char *p = memchr(buf, '\n', count);
 726                if (print)
 727                        fputs(line_prefix, fp);
 728                if (p != buf) {
 729                        if (st_el->color && fputs(st_el->color, fp) < 0)
 730                                return -1;
 731                        if (fputs(st_el->prefix, fp) < 0 ||
 732                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 733                            fputs(st_el->suffix, fp) < 0)
 734                                return -1;
 735                        if (st_el->color && *st_el->color
 736                            && fputs(GIT_COLOR_RESET, fp) < 0)
 737                                return -1;
 738                }
 739                if (!p)
 740                        return 0;
 741                if (fputs(newline, fp) < 0)
 742                        return -1;
 743                count -= p + 1 - buf;
 744                buf = p + 1;
 745                print = 1;
 746        }
 747        return 0;
 748}
 749
 750/*
 751 * '--color-words' algorithm can be described as:
 752 *
 753 *   1. collect a the minus/plus lines of a diff hunk, divided into
 754 *      minus-lines and plus-lines;
 755 *
 756 *   2. break both minus-lines and plus-lines into words and
 757 *      place them into two mmfile_t with one word for each line;
 758 *
 759 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 760 *
 761 * And for the common parts of the both file, we output the plus side text.
 762 * diff_words->current_plus is used to trace the current position of the plus file
 763 * which printed. diff_words->last_minus is used to trace the last minus word
 764 * printed.
 765 *
 766 * For '--graph' to work with '--color-words', we need to output the graph prefix
 767 * on each line of color words output. Generally, there are two conditions on
 768 * which we should output the prefix.
 769 *
 770 *   1. diff_words->last_minus == 0 &&
 771 *      diff_words->current_plus == diff_words->plus.text.ptr
 772 *
 773 *      that is: the plus text must start as a new line, and if there is no minus
 774 *      word printed, a graph prefix must be printed.
 775 *
 776 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 777 *      *(diff_words->current_plus - 1) == '\n'
 778 *
 779 *      that is: a graph prefix must be printed following a '\n'
 780 */
 781static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 782{
 783        if ((diff_words->last_minus == 0 &&
 784                diff_words->current_plus == diff_words->plus.text.ptr) ||
 785                (diff_words->current_plus > diff_words->plus.text.ptr &&
 786                *(diff_words->current_plus - 1) == '\n')) {
 787                return 1;
 788        } else {
 789                return 0;
 790        }
 791}
 792
 793static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 794{
 795        struct diff_words_data *diff_words = priv;
 796        struct diff_words_style *style = diff_words->style;
 797        int minus_first, minus_len, plus_first, plus_len;
 798        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 799        struct diff_options *opt = diff_words->opt;
 800        struct strbuf *msgbuf;
 801        char *line_prefix = "";
 802
 803        if (line[0] != '@' || parse_hunk_header(line, len,
 804                        &minus_first, &minus_len, &plus_first, &plus_len))
 805                return;
 806
 807        assert(opt);
 808        if (opt->output_prefix) {
 809                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 810                line_prefix = msgbuf->buf;
 811        }
 812
 813        /* POSIX requires that first be decremented by one if len == 0... */
 814        if (minus_len) {
 815                minus_begin = diff_words->minus.orig[minus_first].begin;
 816                minus_end =
 817                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 818        } else
 819                minus_begin = minus_end =
 820                        diff_words->minus.orig[minus_first].end;
 821
 822        if (plus_len) {
 823                plus_begin = diff_words->plus.orig[plus_first].begin;
 824                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 825        } else
 826                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 827
 828        if (color_words_output_graph_prefix(diff_words)) {
 829                fputs(line_prefix, diff_words->opt->file);
 830        }
 831        if (diff_words->current_plus != plus_begin) {
 832                fn_out_diff_words_write_helper(diff_words->opt->file,
 833                                &style->ctx, style->newline,
 834                                plus_begin - diff_words->current_plus,
 835                                diff_words->current_plus, line_prefix);
 836                if (*(plus_begin - 1) == '\n')
 837                        fputs(line_prefix, diff_words->opt->file);
 838        }
 839        if (minus_begin != minus_end) {
 840                fn_out_diff_words_write_helper(diff_words->opt->file,
 841                                &style->old, style->newline,
 842                                minus_end - minus_begin, minus_begin,
 843                                line_prefix);
 844        }
 845        if (plus_begin != plus_end) {
 846                fn_out_diff_words_write_helper(diff_words->opt->file,
 847                                &style->new, style->newline,
 848                                plus_end - plus_begin, plus_begin,
 849                                line_prefix);
 850        }
 851
 852        diff_words->current_plus = plus_end;
 853        diff_words->last_minus = minus_first;
 854}
 855
 856/* This function starts looking at *begin, and returns 0 iff a word was found. */
 857static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 858                int *begin, int *end)
 859{
 860        if (word_regex && *begin < buffer->size) {
 861                regmatch_t match[1];
 862                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 863                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 864                                        '\n', match[0].rm_eo - match[0].rm_so);
 865                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 866                        *begin += match[0].rm_so;
 867                        return *begin >= *end;
 868                }
 869                return -1;
 870        }
 871
 872        /* find the next word */
 873        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 874                (*begin)++;
 875        if (*begin >= buffer->size)
 876                return -1;
 877
 878        /* find the end of the word */
 879        *end = *begin + 1;
 880        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 881                (*end)++;
 882
 883        return 0;
 884}
 885
 886/*
 887 * This function splits the words in buffer->text, stores the list with
 888 * newline separator into out, and saves the offsets of the original words
 889 * in buffer->orig.
 890 */
 891static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 892                regex_t *word_regex)
 893{
 894        int i, j;
 895        long alloc = 0;
 896
 897        out->size = 0;
 898        out->ptr = NULL;
 899
 900        /* fake an empty "0th" word */
 901        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 902        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 903        buffer->orig_nr = 1;
 904
 905        for (i = 0; i < buffer->text.size; i++) {
 906                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 907                        return;
 908
 909                /* store original boundaries */
 910                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 911                                buffer->orig_alloc);
 912                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 913                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 914                buffer->orig_nr++;
 915
 916                /* store one word */
 917                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 918                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 919                out->ptr[out->size + j - i] = '\n';
 920                out->size += j - i + 1;
 921
 922                i = j - 1;
 923        }
 924}
 925
 926/* this executes the word diff on the accumulated buffers */
 927static void diff_words_show(struct diff_words_data *diff_words)
 928{
 929        xpparam_t xpp;
 930        xdemitconf_t xecfg;
 931        mmfile_t minus, plus;
 932        struct diff_words_style *style = diff_words->style;
 933
 934        struct diff_options *opt = diff_words->opt;
 935        struct strbuf *msgbuf;
 936        char *line_prefix = "";
 937
 938        assert(opt);
 939        if (opt->output_prefix) {
 940                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 941                line_prefix = msgbuf->buf;
 942        }
 943
 944        /* special case: only removal */
 945        if (!diff_words->plus.text.size) {
 946                fputs(line_prefix, diff_words->opt->file);
 947                fn_out_diff_words_write_helper(diff_words->opt->file,
 948                        &style->old, style->newline,
 949                        diff_words->minus.text.size,
 950                        diff_words->minus.text.ptr, line_prefix);
 951                diff_words->minus.text.size = 0;
 952                return;
 953        }
 954
 955        diff_words->current_plus = diff_words->plus.text.ptr;
 956        diff_words->last_minus = 0;
 957
 958        memset(&xpp, 0, sizeof(xpp));
 959        memset(&xecfg, 0, sizeof(xecfg));
 960        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 961        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 962        xpp.flags = 0;
 963        /* as only the hunk header will be parsed, we need a 0-context */
 964        xecfg.ctxlen = 0;
 965        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 966                      &xpp, &xecfg);
 967        free(minus.ptr);
 968        free(plus.ptr);
 969        if (diff_words->current_plus != diff_words->plus.text.ptr +
 970                        diff_words->plus.text.size) {
 971                if (color_words_output_graph_prefix(diff_words))
 972                        fputs(line_prefix, diff_words->opt->file);
 973                fn_out_diff_words_write_helper(diff_words->opt->file,
 974                        &style->ctx, style->newline,
 975                        diff_words->plus.text.ptr + diff_words->plus.text.size
 976                        - diff_words->current_plus, diff_words->current_plus,
 977                        line_prefix);
 978        }
 979        diff_words->minus.text.size = diff_words->plus.text.size = 0;
 980}
 981
 982/* In "color-words" mode, show word-diff of words accumulated in the buffer */
 983static void diff_words_flush(struct emit_callback *ecbdata)
 984{
 985        if (ecbdata->diff_words->minus.text.size ||
 986            ecbdata->diff_words->plus.text.size)
 987                diff_words_show(ecbdata->diff_words);
 988}
 989
 990static void free_diff_words_data(struct emit_callback *ecbdata)
 991{
 992        if (ecbdata->diff_words) {
 993                diff_words_flush(ecbdata);
 994                free (ecbdata->diff_words->minus.text.ptr);
 995                free (ecbdata->diff_words->minus.orig);
 996                free (ecbdata->diff_words->plus.text.ptr);
 997                free (ecbdata->diff_words->plus.orig);
 998                if (ecbdata->diff_words->word_regex) {
 999                        regfree(ecbdata->diff_words->word_regex);
1000                        free(ecbdata->diff_words->word_regex);
1001                }
1002                free(ecbdata->diff_words);
1003                ecbdata->diff_words = NULL;
1004        }
1005}
1006
1007const char *diff_get_color(int diff_use_color, enum color_diff ix)
1008{
1009        if (want_color(diff_use_color))
1010                return diff_colors[ix];
1011        return "";
1012}
1013
1014static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1015{
1016        const char *cp;
1017        unsigned long allot;
1018        size_t l = len;
1019
1020        if (ecb->truncate)
1021                return ecb->truncate(line, len);
1022        cp = line;
1023        allot = l;
1024        while (0 < l) {
1025                (void) utf8_width(&cp, &l);
1026                if (!cp)
1027                        break; /* truncated in the middle? */
1028        }
1029        return allot - l;
1030}
1031
1032static void find_lno(const char *line, struct emit_callback *ecbdata)
1033{
1034        const char *p;
1035        ecbdata->lno_in_preimage = 0;
1036        ecbdata->lno_in_postimage = 0;
1037        p = strchr(line, '-');
1038        if (!p)
1039                return; /* cannot happen */
1040        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1041        p = strchr(p, '+');
1042        if (!p)
1043                return; /* cannot happen */
1044        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1045}
1046
1047static void fn_out_consume(void *priv, char *line, unsigned long len)
1048{
1049        struct emit_callback *ecbdata = priv;
1050        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1051        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1052        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1053        struct diff_options *o = ecbdata->opt;
1054        char *line_prefix = "";
1055        struct strbuf *msgbuf;
1056
1057        if (o && o->output_prefix) {
1058                msgbuf = o->output_prefix(o, o->output_prefix_data);
1059                line_prefix = msgbuf->buf;
1060        }
1061
1062        if (ecbdata->header) {
1063                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1064                strbuf_reset(ecbdata->header);
1065                ecbdata->header = NULL;
1066        }
1067        *(ecbdata->found_changesp) = 1;
1068
1069        if (ecbdata->label_path[0]) {
1070                const char *name_a_tab, *name_b_tab;
1071
1072                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1073                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1074
1075                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1076                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1077                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1078                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1079                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1080        }
1081
1082        if (diff_suppress_blank_empty
1083            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1084                line[0] = '\n';
1085                len = 1;
1086        }
1087
1088        if (line[0] == '@') {
1089                if (ecbdata->diff_words)
1090                        diff_words_flush(ecbdata);
1091                len = sane_truncate_line(ecbdata, line, len);
1092                find_lno(line, ecbdata);
1093                emit_hunk_header(ecbdata, line, len);
1094                if (line[len-1] != '\n')
1095                        putc('\n', ecbdata->opt->file);
1096                return;
1097        }
1098
1099        if (len < 1) {
1100                emit_line(ecbdata->opt, reset, reset, line, len);
1101                if (ecbdata->diff_words
1102                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1103                        fputs("~\n", ecbdata->opt->file);
1104                return;
1105        }
1106
1107        if (ecbdata->diff_words) {
1108                if (line[0] == '-') {
1109                        diff_words_append(line, len,
1110                                          &ecbdata->diff_words->minus);
1111                        return;
1112                } else if (line[0] == '+') {
1113                        diff_words_append(line, len,
1114                                          &ecbdata->diff_words->plus);
1115                        return;
1116                }
1117                diff_words_flush(ecbdata);
1118                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1119                        emit_line(ecbdata->opt, plain, reset, line, len);
1120                        fputs("~\n", ecbdata->opt->file);
1121                } else {
1122                        /*
1123                         * Skip the prefix character, if any.  With
1124                         * diff_suppress_blank_empty, there may be
1125                         * none.
1126                         */
1127                        if (line[0] != '\n') {
1128                              line++;
1129                              len--;
1130                        }
1131                        emit_line(ecbdata->opt, plain, reset, line, len);
1132                }
1133                return;
1134        }
1135
1136        if (line[0] != '+') {
1137                const char *color =
1138                        diff_get_color(ecbdata->color_diff,
1139                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1140                ecbdata->lno_in_preimage++;
1141                if (line[0] == ' ')
1142                        ecbdata->lno_in_postimage++;
1143                emit_line(ecbdata->opt, color, reset, line, len);
1144        } else {
1145                ecbdata->lno_in_postimage++;
1146                emit_add_line(reset, ecbdata, line + 1, len - 1);
1147        }
1148}
1149
1150static char *pprint_rename(const char *a, const char *b)
1151{
1152        const char *old = a;
1153        const char *new = b;
1154        struct strbuf name = STRBUF_INIT;
1155        int pfx_length, sfx_length;
1156        int len_a = strlen(a);
1157        int len_b = strlen(b);
1158        int a_midlen, b_midlen;
1159        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1160        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1161
1162        if (qlen_a || qlen_b) {
1163                quote_c_style(a, &name, NULL, 0);
1164                strbuf_addstr(&name, " => ");
1165                quote_c_style(b, &name, NULL, 0);
1166                return strbuf_detach(&name, NULL);
1167        }
1168
1169        /* Find common prefix */
1170        pfx_length = 0;
1171        while (*old && *new && *old == *new) {
1172                if (*old == '/')
1173                        pfx_length = old - a + 1;
1174                old++;
1175                new++;
1176        }
1177
1178        /* Find common suffix */
1179        old = a + len_a;
1180        new = b + len_b;
1181        sfx_length = 0;
1182        while (a <= old && b <= new && *old == *new) {
1183                if (*old == '/')
1184                        sfx_length = len_a - (old - a);
1185                old--;
1186                new--;
1187        }
1188
1189        /*
1190         * pfx{mid-a => mid-b}sfx
1191         * {pfx-a => pfx-b}sfx
1192         * pfx{sfx-a => sfx-b}
1193         * name-a => name-b
1194         */
1195        a_midlen = len_a - pfx_length - sfx_length;
1196        b_midlen = len_b - pfx_length - sfx_length;
1197        if (a_midlen < 0)
1198                a_midlen = 0;
1199        if (b_midlen < 0)
1200                b_midlen = 0;
1201
1202        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1203        if (pfx_length + sfx_length) {
1204                strbuf_add(&name, a, pfx_length);
1205                strbuf_addch(&name, '{');
1206        }
1207        strbuf_add(&name, a + pfx_length, a_midlen);
1208        strbuf_addstr(&name, " => ");
1209        strbuf_add(&name, b + pfx_length, b_midlen);
1210        if (pfx_length + sfx_length) {
1211                strbuf_addch(&name, '}');
1212                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1213        }
1214        return strbuf_detach(&name, NULL);
1215}
1216
1217struct diffstat_t {
1218        int nr;
1219        int alloc;
1220        struct diffstat_file {
1221                char *from_name;
1222                char *name;
1223                char *print_name;
1224                unsigned is_unmerged:1;
1225                unsigned is_binary:1;
1226                unsigned is_renamed:1;
1227                uintmax_t added, deleted;
1228        } **files;
1229};
1230
1231static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1232                                          const char *name_a,
1233                                          const char *name_b)
1234{
1235        struct diffstat_file *x;
1236        x = xcalloc(sizeof (*x), 1);
1237        if (diffstat->nr == diffstat->alloc) {
1238                diffstat->alloc = alloc_nr(diffstat->alloc);
1239                diffstat->files = xrealloc(diffstat->files,
1240                                diffstat->alloc * sizeof(x));
1241        }
1242        diffstat->files[diffstat->nr++] = x;
1243        if (name_b) {
1244                x->from_name = xstrdup(name_a);
1245                x->name = xstrdup(name_b);
1246                x->is_renamed = 1;
1247        }
1248        else {
1249                x->from_name = NULL;
1250                x->name = xstrdup(name_a);
1251        }
1252        return x;
1253}
1254
1255static void diffstat_consume(void *priv, char *line, unsigned long len)
1256{
1257        struct diffstat_t *diffstat = priv;
1258        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1259
1260        if (line[0] == '+')
1261                x->added++;
1262        else if (line[0] == '-')
1263                x->deleted++;
1264}
1265
1266const char mime_boundary_leader[] = "------------";
1267
1268static int scale_linear(int it, int width, int max_change)
1269{
1270        /*
1271         * make sure that at least one '-' is printed if there were deletions,
1272         * and likewise for '+'.
1273         */
1274        if (max_change < 2)
1275                return it;
1276        return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
1277}
1278
1279static void show_name(FILE *file,
1280                      const char *prefix, const char *name, int len)
1281{
1282        fprintf(file, " %s%-*s |", prefix, len, name);
1283}
1284
1285static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1286{
1287        if (cnt <= 0)
1288                return;
1289        fprintf(file, "%s", set);
1290        while (cnt--)
1291                putc(ch, file);
1292        fprintf(file, "%s", reset);
1293}
1294
1295static void fill_print_name(struct diffstat_file *file)
1296{
1297        char *pname;
1298
1299        if (file->print_name)
1300                return;
1301
1302        if (!file->is_renamed) {
1303                struct strbuf buf = STRBUF_INIT;
1304                if (quote_c_style(file->name, &buf, NULL, 0)) {
1305                        pname = strbuf_detach(&buf, NULL);
1306                } else {
1307                        pname = file->name;
1308                        strbuf_release(&buf);
1309                }
1310        } else {
1311                pname = pprint_rename(file->from_name, file->name);
1312        }
1313        file->print_name = pname;
1314}
1315
1316static void show_stats(struct diffstat_t *data, struct diff_options *options)
1317{
1318        int i, len, add, del, adds = 0, dels = 0;
1319        uintmax_t max_change = 0, max_len = 0;
1320        int total_files = data->nr;
1321        int width, name_width, count;
1322        const char *reset, *add_c, *del_c;
1323        const char *line_prefix = "";
1324        int extra_shown = 0;
1325        struct strbuf *msg = NULL;
1326
1327        if (data->nr == 0)
1328                return;
1329
1330        if (options->output_prefix) {
1331                msg = options->output_prefix(options, options->output_prefix_data);
1332                line_prefix = msg->buf;
1333        }
1334
1335        width = options->stat_width ? options->stat_width : 80;
1336        name_width = options->stat_name_width ? options->stat_name_width : 50;
1337        count = options->stat_count ? options->stat_count : data->nr;
1338
1339        /* Sanity: give at least 5 columns to the graph,
1340         * but leave at least 10 columns for the name.
1341         */
1342        if (width < 25)
1343                width = 25;
1344        if (name_width < 10)
1345                name_width = 10;
1346        else if (width < name_width + 15)
1347                name_width = width - 15;
1348
1349        /* Find the longest filename and max number of changes */
1350        reset = diff_get_color_opt(options, DIFF_RESET);
1351        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1352        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1353
1354        for (i = 0; (i < count) && (i < data->nr); i++) {
1355                struct diffstat_file *file = data->files[i];
1356                uintmax_t change = file->added + file->deleted;
1357                if (!data->files[i]->is_renamed &&
1358                         (change == 0)) {
1359                        count++; /* not shown == room for one more */
1360                        continue;
1361                }
1362                fill_print_name(file);
1363                len = strlen(file->print_name);
1364                if (max_len < len)
1365                        max_len = len;
1366
1367                if (file->is_binary || file->is_unmerged)
1368                        continue;
1369                if (max_change < change)
1370                        max_change = change;
1371        }
1372        count = i; /* min(count, data->nr) */
1373
1374        /* Compute the width of the graph part;
1375         * 10 is for one blank at the beginning of the line plus
1376         * " | count " between the name and the graph.
1377         *
1378         * From here on, name_width is the width of the name area,
1379         * and width is the width of the graph area.
1380         */
1381        name_width = (name_width < max_len) ? name_width : max_len;
1382        if (width < (name_width + 10) + max_change)
1383                width = width - (name_width + 10);
1384        else
1385                width = max_change;
1386
1387        for (i = 0; i < count; i++) {
1388                const char *prefix = "";
1389                char *name = data->files[i]->print_name;
1390                uintmax_t added = data->files[i]->added;
1391                uintmax_t deleted = data->files[i]->deleted;
1392                int name_len;
1393
1394                if (!data->files[i]->is_renamed &&
1395                         (added + deleted == 0)) {
1396                        total_files--;
1397                        continue;
1398                }
1399                /*
1400                 * "scale" the filename
1401                 */
1402                len = name_width;
1403                name_len = strlen(name);
1404                if (name_width < name_len) {
1405                        char *slash;
1406                        prefix = "...";
1407                        len -= 3;
1408                        name += name_len - len;
1409                        slash = strchr(name, '/');
1410                        if (slash)
1411                                name = slash;
1412                }
1413
1414                if (data->files[i]->is_binary) {
1415                        fprintf(options->file, "%s", line_prefix);
1416                        show_name(options->file, prefix, name, len);
1417                        fprintf(options->file, "  Bin ");
1418                        fprintf(options->file, "%s%"PRIuMAX"%s",
1419                                del_c, deleted, reset);
1420                        fprintf(options->file, " -> ");
1421                        fprintf(options->file, "%s%"PRIuMAX"%s",
1422                                add_c, added, reset);
1423                        fprintf(options->file, " bytes");
1424                        fprintf(options->file, "\n");
1425                        continue;
1426                }
1427                else if (data->files[i]->is_unmerged) {
1428                        fprintf(options->file, "%s", line_prefix);
1429                        show_name(options->file, prefix, name, len);
1430                        fprintf(options->file, "  Unmerged\n");
1431                        continue;
1432                }
1433
1434                /*
1435                 * scale the add/delete
1436                 */
1437                add = added;
1438                del = deleted;
1439                adds += add;
1440                dels += del;
1441
1442                if (width <= max_change) {
1443                        add = scale_linear(add, width, max_change);
1444                        del = scale_linear(del, width, max_change);
1445                }
1446                fprintf(options->file, "%s", line_prefix);
1447                show_name(options->file, prefix, name, len);
1448                fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
1449                                added + deleted ? " " : "");
1450                show_graph(options->file, '+', add, add_c, reset);
1451                show_graph(options->file, '-', del, del_c, reset);
1452                fprintf(options->file, "\n");
1453        }
1454        for (i = count; i < data->nr; i++) {
1455                uintmax_t added = data->files[i]->added;
1456                uintmax_t deleted = data->files[i]->deleted;
1457                if (!data->files[i]->is_renamed &&
1458                         (added + deleted == 0)) {
1459                        total_files--;
1460                        continue;
1461                }
1462                adds += added;
1463                dels += deleted;
1464                if (!extra_shown)
1465                        fprintf(options->file, "%s ...\n", line_prefix);
1466                extra_shown = 1;
1467        }
1468        fprintf(options->file, "%s", line_prefix);
1469        fprintf(options->file,
1470               " %d files changed, %d insertions(+), %d deletions(-)\n",
1471               total_files, adds, dels);
1472}
1473
1474static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1475{
1476        int i, adds = 0, dels = 0, total_files = data->nr;
1477
1478        if (data->nr == 0)
1479                return;
1480
1481        for (i = 0; i < data->nr; i++) {
1482                if (!data->files[i]->is_binary &&
1483                    !data->files[i]->is_unmerged) {
1484                        int added = data->files[i]->added;
1485                        int deleted= data->files[i]->deleted;
1486                        if (!data->files[i]->is_renamed &&
1487                            (added + deleted == 0)) {
1488                                total_files--;
1489                        } else {
1490                                adds += added;
1491                                dels += deleted;
1492                        }
1493                }
1494        }
1495        if (options->output_prefix) {
1496                struct strbuf *msg = NULL;
1497                msg = options->output_prefix(options,
1498                                options->output_prefix_data);
1499                fprintf(options->file, "%s", msg->buf);
1500        }
1501        fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
1502               total_files, adds, dels);
1503}
1504
1505static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1506{
1507        int i;
1508
1509        if (data->nr == 0)
1510                return;
1511
1512        for (i = 0; i < data->nr; i++) {
1513                struct diffstat_file *file = data->files[i];
1514
1515                if (options->output_prefix) {
1516                        struct strbuf *msg = NULL;
1517                        msg = options->output_prefix(options,
1518                                        options->output_prefix_data);
1519                        fprintf(options->file, "%s", msg->buf);
1520                }
1521
1522                if (file->is_binary)
1523                        fprintf(options->file, "-\t-\t");
1524                else
1525                        fprintf(options->file,
1526                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1527                                file->added, file->deleted);
1528                if (options->line_termination) {
1529                        fill_print_name(file);
1530                        if (!file->is_renamed)
1531                                write_name_quoted(file->name, options->file,
1532                                                  options->line_termination);
1533                        else {
1534                                fputs(file->print_name, options->file);
1535                                putc(options->line_termination, options->file);
1536                        }
1537                } else {
1538                        if (file->is_renamed) {
1539                                putc('\0', options->file);
1540                                write_name_quoted(file->from_name, options->file, '\0');
1541                        }
1542                        write_name_quoted(file->name, options->file, '\0');
1543                }
1544        }
1545}
1546
1547struct dirstat_file {
1548        const char *name;
1549        unsigned long changed;
1550};
1551
1552struct dirstat_dir {
1553        struct dirstat_file *files;
1554        int alloc, nr, permille, cumulative;
1555};
1556
1557static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1558                unsigned long changed, const char *base, int baselen)
1559{
1560        unsigned long this_dir = 0;
1561        unsigned int sources = 0;
1562        const char *line_prefix = "";
1563        struct strbuf *msg = NULL;
1564
1565        if (opt->output_prefix) {
1566                msg = opt->output_prefix(opt, opt->output_prefix_data);
1567                line_prefix = msg->buf;
1568        }
1569
1570        while (dir->nr) {
1571                struct dirstat_file *f = dir->files;
1572                int namelen = strlen(f->name);
1573                unsigned long this;
1574                char *slash;
1575
1576                if (namelen < baselen)
1577                        break;
1578                if (memcmp(f->name, base, baselen))
1579                        break;
1580                slash = strchr(f->name + baselen, '/');
1581                if (slash) {
1582                        int newbaselen = slash + 1 - f->name;
1583                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1584                        sources++;
1585                } else {
1586                        this = f->changed;
1587                        dir->files++;
1588                        dir->nr--;
1589                        sources += 2;
1590                }
1591                this_dir += this;
1592        }
1593
1594        /*
1595         * We don't report dirstat's for
1596         *  - the top level
1597         *  - or cases where everything came from a single directory
1598         *    under this directory (sources == 1).
1599         */
1600        if (baselen && sources != 1) {
1601                if (this_dir) {
1602                        int permille = this_dir * 1000 / changed;
1603                        if (permille >= dir->permille) {
1604                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1605                                        permille / 10, permille % 10, baselen, base);
1606                                if (!dir->cumulative)
1607                                        return 0;
1608                        }
1609                }
1610        }
1611        return this_dir;
1612}
1613
1614static int dirstat_compare(const void *_a, const void *_b)
1615{
1616        const struct dirstat_file *a = _a;
1617        const struct dirstat_file *b = _b;
1618        return strcmp(a->name, b->name);
1619}
1620
1621static void show_dirstat(struct diff_options *options)
1622{
1623        int i;
1624        unsigned long changed;
1625        struct dirstat_dir dir;
1626        struct diff_queue_struct *q = &diff_queued_diff;
1627
1628        dir.files = NULL;
1629        dir.alloc = 0;
1630        dir.nr = 0;
1631        dir.permille = options->dirstat_permille;
1632        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1633
1634        changed = 0;
1635        for (i = 0; i < q->nr; i++) {
1636                struct diff_filepair *p = q->queue[i];
1637                const char *name;
1638                unsigned long copied, added, damage;
1639                int content_changed;
1640
1641                name = p->two->path ? p->two->path : p->one->path;
1642
1643                if (p->one->sha1_valid && p->two->sha1_valid)
1644                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1645                else
1646                        content_changed = 1;
1647
1648                if (!content_changed) {
1649                        /*
1650                         * The SHA1 has not changed, so pre-/post-content is
1651                         * identical. We can therefore skip looking at the
1652                         * file contents altogether.
1653                         */
1654                        damage = 0;
1655                        goto found_damage;
1656                }
1657
1658                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1659                        /*
1660                         * In --dirstat-by-file mode, we don't really need to
1661                         * look at the actual file contents at all.
1662                         * The fact that the SHA1 changed is enough for us to
1663                         * add this file to the list of results
1664                         * (with each file contributing equal damage).
1665                         */
1666                        damage = 1;
1667                        goto found_damage;
1668                }
1669
1670                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1671                        diff_populate_filespec(p->one, 0);
1672                        diff_populate_filespec(p->two, 0);
1673                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1674                                               &copied, &added);
1675                        diff_free_filespec_data(p->one);
1676                        diff_free_filespec_data(p->two);
1677                } else if (DIFF_FILE_VALID(p->one)) {
1678                        diff_populate_filespec(p->one, 1);
1679                        copied = added = 0;
1680                        diff_free_filespec_data(p->one);
1681                } else if (DIFF_FILE_VALID(p->two)) {
1682                        diff_populate_filespec(p->two, 1);
1683                        copied = 0;
1684                        added = p->two->size;
1685                        diff_free_filespec_data(p->two);
1686                } else
1687                        continue;
1688
1689                /*
1690                 * Original minus copied is the removed material,
1691                 * added is the new material.  They are both damages
1692                 * made to the preimage.
1693                 * If the resulting damage is zero, we know that
1694                 * diffcore_count_changes() considers the two entries to
1695                 * be identical, but since content_changed is true, we
1696                 * know that there must have been _some_ kind of change,
1697                 * so we force all entries to have damage > 0.
1698                 */
1699                damage = (p->one->size - copied) + added;
1700                if (!damage)
1701                        damage = 1;
1702
1703found_damage:
1704                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1705                dir.files[dir.nr].name = name;
1706                dir.files[dir.nr].changed = damage;
1707                changed += damage;
1708                dir.nr++;
1709        }
1710
1711        /* This can happen even with many files, if everything was renames */
1712        if (!changed)
1713                return;
1714
1715        /* Show all directories with more than x% of the changes */
1716        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1717        gather_dirstat(options, &dir, changed, "", 0);
1718}
1719
1720static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1721{
1722        int i;
1723        unsigned long changed;
1724        struct dirstat_dir dir;
1725
1726        if (data->nr == 0)
1727                return;
1728
1729        dir.files = NULL;
1730        dir.alloc = 0;
1731        dir.nr = 0;
1732        dir.permille = options->dirstat_permille;
1733        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1734
1735        changed = 0;
1736        for (i = 0; i < data->nr; i++) {
1737                struct diffstat_file *file = data->files[i];
1738                unsigned long damage = file->added + file->deleted;
1739                if (file->is_binary)
1740                        /*
1741                         * binary files counts bytes, not lines. Must find some
1742                         * way to normalize binary bytes vs. textual lines.
1743                         * The following heuristic assumes that there are 64
1744                         * bytes per "line".
1745                         * This is stupid and ugly, but very cheap...
1746                         */
1747                        damage = (damage + 63) / 64;
1748                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1749                dir.files[dir.nr].name = file->name;
1750                dir.files[dir.nr].changed = damage;
1751                changed += damage;
1752                dir.nr++;
1753        }
1754
1755        /* This can happen even with many files, if everything was renames */
1756        if (!changed)
1757                return;
1758
1759        /* Show all directories with more than x% of the changes */
1760        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1761        gather_dirstat(options, &dir, changed, "", 0);
1762}
1763
1764static void free_diffstat_info(struct diffstat_t *diffstat)
1765{
1766        int i;
1767        for (i = 0; i < diffstat->nr; i++) {
1768                struct diffstat_file *f = diffstat->files[i];
1769                if (f->name != f->print_name)
1770                        free(f->print_name);
1771                free(f->name);
1772                free(f->from_name);
1773                free(f);
1774        }
1775        free(diffstat->files);
1776}
1777
1778struct checkdiff_t {
1779        const char *filename;
1780        int lineno;
1781        int conflict_marker_size;
1782        struct diff_options *o;
1783        unsigned ws_rule;
1784        unsigned status;
1785};
1786
1787static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
1788{
1789        char firstchar;
1790        int cnt;
1791
1792        if (len < marker_size + 1)
1793                return 0;
1794        firstchar = line[0];
1795        switch (firstchar) {
1796        case '=': case '>': case '<': case '|':
1797                break;
1798        default:
1799                return 0;
1800        }
1801        for (cnt = 1; cnt < marker_size; cnt++)
1802                if (line[cnt] != firstchar)
1803                        return 0;
1804        /* line[1] thru line[marker_size-1] are same as firstchar */
1805        if (len < marker_size + 1 || !isspace(line[marker_size]))
1806                return 0;
1807        return 1;
1808}
1809
1810static void checkdiff_consume(void *priv, char *line, unsigned long len)
1811{
1812        struct checkdiff_t *data = priv;
1813        int marker_size = data->conflict_marker_size;
1814        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
1815        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
1816        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
1817        char *err;
1818        char *line_prefix = "";
1819        struct strbuf *msgbuf;
1820
1821        assert(data->o);
1822        if (data->o->output_prefix) {
1823                msgbuf = data->o->output_prefix(data->o,
1824                        data->o->output_prefix_data);
1825                line_prefix = msgbuf->buf;
1826        }
1827
1828        if (line[0] == '+') {
1829                unsigned bad;
1830                data->lineno++;
1831                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
1832                        data->status |= 1;
1833                        fprintf(data->o->file,
1834                                "%s%s:%d: leftover conflict marker\n",
1835                                line_prefix, data->filename, data->lineno);
1836                }
1837                bad = ws_check(line + 1, len - 1, data->ws_rule);
1838                if (!bad)
1839                        return;
1840                data->status |= bad;
1841                err = whitespace_error_string(bad);
1842                fprintf(data->o->file, "%s%s:%d: %s.\n",
1843                        line_prefix, data->filename, data->lineno, err);
1844                free(err);
1845                emit_line(data->o, set, reset, line, 1);
1846                ws_check_emit(line + 1, len - 1, data->ws_rule,
1847                              data->o->file, set, reset, ws);
1848        } else if (line[0] == ' ') {
1849                data->lineno++;
1850        } else if (line[0] == '@') {
1851                char *plus = strchr(line, '+');
1852                if (plus)
1853                        data->lineno = strtol(plus, NULL, 10) - 1;
1854                else
1855                        die("invalid diff");
1856        }
1857}
1858
1859static unsigned char *deflate_it(char *data,
1860                                 unsigned long size,
1861                                 unsigned long *result_size)
1862{
1863        int bound;
1864        unsigned char *deflated;
1865        git_zstream stream;
1866
1867        memset(&stream, 0, sizeof(stream));
1868        git_deflate_init(&stream, zlib_compression_level);
1869        bound = git_deflate_bound(&stream, size);
1870        deflated = xmalloc(bound);
1871        stream.next_out = deflated;
1872        stream.avail_out = bound;
1873
1874        stream.next_in = (unsigned char *)data;
1875        stream.avail_in = size;
1876        while (git_deflate(&stream, Z_FINISH) == Z_OK)
1877                ; /* nothing */
1878        git_deflate_end(&stream);
1879        *result_size = stream.total_out;
1880        return deflated;
1881}
1882
1883static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1884{
1885        void *cp;
1886        void *delta;
1887        void *deflated;
1888        void *data;
1889        unsigned long orig_size;
1890        unsigned long delta_size;
1891        unsigned long deflate_size;
1892        unsigned long data_size;
1893
1894        /* We could do deflated delta, or we could do just deflated two,
1895         * whichever is smaller.
1896         */
1897        delta = NULL;
1898        deflated = deflate_it(two->ptr, two->size, &deflate_size);
1899        if (one->size && two->size) {
1900                delta = diff_delta(one->ptr, one->size,
1901                                   two->ptr, two->size,
1902                                   &delta_size, deflate_size);
1903                if (delta) {
1904                        void *to_free = delta;
1905                        orig_size = delta_size;
1906                        delta = deflate_it(delta, delta_size, &delta_size);
1907                        free(to_free);
1908                }
1909        }
1910
1911        if (delta && delta_size < deflate_size) {
1912                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
1913                free(deflated);
1914                data = delta;
1915                data_size = delta_size;
1916        }
1917        else {
1918                fprintf(file, "%sliteral %lu\n", prefix, two->size);
1919                free(delta);
1920                data = deflated;
1921                data_size = deflate_size;
1922        }
1923
1924        /* emit data encoded in base85 */
1925        cp = data;
1926        while (data_size) {
1927                int bytes = (52 < data_size) ? 52 : data_size;
1928                char line[70];
1929                data_size -= bytes;
1930                if (bytes <= 26)
1931                        line[0] = bytes + 'A' - 1;
1932                else
1933                        line[0] = bytes - 26 + 'a' - 1;
1934                encode_85(line + 1, cp, bytes);
1935                cp = (char *) cp + bytes;
1936                fprintf(file, "%s", prefix);
1937                fputs(line, file);
1938                fputc('\n', file);
1939        }
1940        fprintf(file, "%s\n", prefix);
1941        free(data);
1942}
1943
1944static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
1945{
1946        fprintf(file, "%sGIT binary patch\n", prefix);
1947        emit_binary_diff_body(file, one, two, prefix);
1948        emit_binary_diff_body(file, two, one, prefix);
1949}
1950
1951static void diff_filespec_load_driver(struct diff_filespec *one)
1952{
1953        /* Use already-loaded driver */
1954        if (one->driver)
1955                return;
1956
1957        if (S_ISREG(one->mode))
1958                one->driver = userdiff_find_by_path(one->path);
1959
1960        /* Fallback to default settings */
1961        if (!one->driver)
1962                one->driver = userdiff_find_by_name("default");
1963}
1964
1965int diff_filespec_is_binary(struct diff_filespec *one)
1966{
1967        if (one->is_binary == -1) {
1968                diff_filespec_load_driver(one);
1969                if (one->driver->binary != -1)
1970                        one->is_binary = one->driver->binary;
1971                else {
1972                        if (!one->data && DIFF_FILE_VALID(one))
1973                                diff_populate_filespec(one, 0);
1974                        if (one->data)
1975                                one->is_binary = buffer_is_binary(one->data,
1976                                                one->size);
1977                        if (one->is_binary == -1)
1978                                one->is_binary = 0;
1979                }
1980        }
1981        return one->is_binary;
1982}
1983
1984static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
1985{
1986        diff_filespec_load_driver(one);
1987        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
1988}
1989
1990static const char *userdiff_word_regex(struct diff_filespec *one)
1991{
1992        diff_filespec_load_driver(one);
1993        return one->driver->word_regex;
1994}
1995
1996void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
1997{
1998        if (!options->a_prefix)
1999                options->a_prefix = a;
2000        if (!options->b_prefix)
2001                options->b_prefix = b;
2002}
2003
2004struct userdiff_driver *get_textconv(struct diff_filespec *one)
2005{
2006        if (!DIFF_FILE_VALID(one))
2007                return NULL;
2008
2009        diff_filespec_load_driver(one);
2010        return userdiff_get_textconv(one->driver);
2011}
2012
2013static void builtin_diff(const char *name_a,
2014                         const char *name_b,
2015                         struct diff_filespec *one,
2016                         struct diff_filespec *two,
2017                         const char *xfrm_msg,
2018                         int must_show_header,
2019                         struct diff_options *o,
2020                         int complete_rewrite)
2021{
2022        mmfile_t mf1, mf2;
2023        const char *lbl[2];
2024        char *a_one, *b_two;
2025        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
2026        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2027        const char *a_prefix, *b_prefix;
2028        struct userdiff_driver *textconv_one = NULL;
2029        struct userdiff_driver *textconv_two = NULL;
2030        struct strbuf header = STRBUF_INIT;
2031        struct strbuf *msgbuf;
2032        char *line_prefix = "";
2033
2034        if (o->output_prefix) {
2035                msgbuf = o->output_prefix(o, o->output_prefix_data);
2036                line_prefix = msgbuf->buf;
2037        }
2038
2039        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2040                        (!one->mode || S_ISGITLINK(one->mode)) &&
2041                        (!two->mode || S_ISGITLINK(two->mode))) {
2042                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2043                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2044                show_submodule_summary(o->file, one ? one->path : two->path,
2045                                one->sha1, two->sha1, two->dirty_submodule,
2046                                del, add, reset);
2047                return;
2048        }
2049
2050        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2051                textconv_one = get_textconv(one);
2052                textconv_two = get_textconv(two);
2053        }
2054
2055        diff_set_mnemonic_prefix(o, "a/", "b/");
2056        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2057                a_prefix = o->b_prefix;
2058                b_prefix = o->a_prefix;
2059        } else {
2060                a_prefix = o->a_prefix;
2061                b_prefix = o->b_prefix;
2062        }
2063
2064        /* Never use a non-valid filename anywhere if at all possible */
2065        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2066        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2067
2068        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2069        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2070        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2071        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2072        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
2073        if (lbl[0][0] == '/') {
2074                /* /dev/null */
2075                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
2076                if (xfrm_msg)
2077                        strbuf_addstr(&header, xfrm_msg);
2078                must_show_header = 1;
2079        }
2080        else if (lbl[1][0] == '/') {
2081                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
2082                if (xfrm_msg)
2083                        strbuf_addstr(&header, xfrm_msg);
2084                must_show_header = 1;
2085        }
2086        else {
2087                if (one->mode != two->mode) {
2088                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
2089                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
2090                        must_show_header = 1;
2091                }
2092                if (xfrm_msg)
2093                        strbuf_addstr(&header, xfrm_msg);
2094
2095                /*
2096                 * we do not run diff between different kind
2097                 * of objects.
2098                 */
2099                if ((one->mode ^ two->mode) & S_IFMT)
2100                        goto free_ab_and_return;
2101                if (complete_rewrite &&
2102                    (textconv_one || !diff_filespec_is_binary(one)) &&
2103                    (textconv_two || !diff_filespec_is_binary(two))) {
2104                        fprintf(o->file, "%s", header.buf);
2105                        strbuf_reset(&header);
2106                        emit_rewrite_diff(name_a, name_b, one, two,
2107                                                textconv_one, textconv_two, o);
2108                        o->found_changes = 1;
2109                        goto free_ab_and_return;
2110                }
2111        }
2112
2113        if (o->irreversible_delete && lbl[1][0] == '/') {
2114                fprintf(o->file, "%s", header.buf);
2115                strbuf_reset(&header);
2116                goto free_ab_and_return;
2117        } else if (!DIFF_OPT_TST(o, TEXT) &&
2118            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2119              (!textconv_two && diff_filespec_is_binary(two)) )) {
2120                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2121                        die("unable to read files to diff");
2122                /* Quite common confusing case */
2123                if (mf1.size == mf2.size &&
2124                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2125                        if (must_show_header)
2126                                fprintf(o->file, "%s", header.buf);
2127                        goto free_ab_and_return;
2128                }
2129                fprintf(o->file, "%s", header.buf);
2130                strbuf_reset(&header);
2131                if (DIFF_OPT_TST(o, BINARY))
2132                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2133                else
2134                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2135                                line_prefix, lbl[0], lbl[1]);
2136                o->found_changes = 1;
2137        } else {
2138                /* Crazy xdl interfaces.. */
2139                const char *diffopts = getenv("GIT_DIFF_OPTS");
2140                xpparam_t xpp;
2141                xdemitconf_t xecfg;
2142                struct emit_callback ecbdata;
2143                const struct userdiff_funcname *pe;
2144
2145                if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
2146                        fprintf(o->file, "%s", header.buf);
2147                        strbuf_reset(&header);
2148                }
2149
2150                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2151                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2152
2153                pe = diff_funcname_pattern(one);
2154                if (!pe)
2155                        pe = diff_funcname_pattern(two);
2156
2157                memset(&xpp, 0, sizeof(xpp));
2158                memset(&xecfg, 0, sizeof(xecfg));
2159                memset(&ecbdata, 0, sizeof(ecbdata));
2160                ecbdata.label_path = lbl;
2161                ecbdata.color_diff = want_color(o->use_color);
2162                ecbdata.found_changesp = &o->found_changes;
2163                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2164                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2165                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2166                ecbdata.opt = o;
2167                ecbdata.header = header.len ? &header : NULL;
2168                xpp.flags = o->xdl_opts;
2169                xecfg.ctxlen = o->context;
2170                xecfg.interhunkctxlen = o->interhunkcontext;
2171                xecfg.flags = XDL_EMIT_FUNCNAMES;
2172                if (pe)
2173                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2174                if (!diffopts)
2175                        ;
2176                else if (!prefixcmp(diffopts, "--unified="))
2177                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2178                else if (!prefixcmp(diffopts, "-u"))
2179                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2180                if (o->word_diff) {
2181                        int i;
2182
2183                        ecbdata.diff_words =
2184                                xcalloc(1, sizeof(struct diff_words_data));
2185                        ecbdata.diff_words->type = o->word_diff;
2186                        ecbdata.diff_words->opt = o;
2187                        if (!o->word_regex)
2188                                o->word_regex = userdiff_word_regex(one);
2189                        if (!o->word_regex)
2190                                o->word_regex = userdiff_word_regex(two);
2191                        if (!o->word_regex)
2192                                o->word_regex = diff_word_regex_cfg;
2193                        if (o->word_regex) {
2194                                ecbdata.diff_words->word_regex = (regex_t *)
2195                                        xmalloc(sizeof(regex_t));
2196                                if (regcomp(ecbdata.diff_words->word_regex,
2197                                                o->word_regex,
2198                                                REG_EXTENDED | REG_NEWLINE))
2199                                        die ("Invalid regular expression: %s",
2200                                                        o->word_regex);
2201                        }
2202                        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2203                                if (o->word_diff == diff_words_styles[i].type) {
2204                                        ecbdata.diff_words->style =
2205                                                &diff_words_styles[i];
2206                                        break;
2207                                }
2208                        }
2209                        if (want_color(o->use_color)) {
2210                                struct diff_words_style *st = ecbdata.diff_words->style;
2211                                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2212                                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2213                                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
2214                        }
2215                }
2216                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2217                              &xpp, &xecfg);
2218                if (o->word_diff)
2219                        free_diff_words_data(&ecbdata);
2220                if (textconv_one)
2221                        free(mf1.ptr);
2222                if (textconv_two)
2223                        free(mf2.ptr);
2224                xdiff_clear_find_func(&xecfg);
2225        }
2226
2227 free_ab_and_return:
2228        strbuf_release(&header);
2229        diff_free_filespec_data(one);
2230        diff_free_filespec_data(two);
2231        free(a_one);
2232        free(b_two);
2233        return;
2234}
2235
2236static void builtin_diffstat(const char *name_a, const char *name_b,
2237                             struct diff_filespec *one,
2238                             struct diff_filespec *two,
2239                             struct diffstat_t *diffstat,
2240                             struct diff_options *o,
2241                             int complete_rewrite)
2242{
2243        mmfile_t mf1, mf2;
2244        struct diffstat_file *data;
2245
2246        data = diffstat_add(diffstat, name_a, name_b);
2247
2248        if (!one || !two) {
2249                data->is_unmerged = 1;
2250                return;
2251        }
2252
2253        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2254                data->is_binary = 1;
2255                data->added = diff_filespec_size(two);
2256                data->deleted = diff_filespec_size(one);
2257        }
2258
2259        else if (complete_rewrite) {
2260                diff_populate_filespec(one, 0);
2261                diff_populate_filespec(two, 0);
2262                data->deleted = count_lines(one->data, one->size);
2263                data->added = count_lines(two->data, two->size);
2264        }
2265
2266        else {
2267                /* Crazy xdl interfaces.. */
2268                xpparam_t xpp;
2269                xdemitconf_t xecfg;
2270
2271                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2272                        die("unable to read files to diff");
2273
2274                memset(&xpp, 0, sizeof(xpp));
2275                memset(&xecfg, 0, sizeof(xecfg));
2276                xpp.flags = o->xdl_opts;
2277                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2278                              &xpp, &xecfg);
2279        }
2280
2281        diff_free_filespec_data(one);
2282        diff_free_filespec_data(two);
2283}
2284
2285static void builtin_checkdiff(const char *name_a, const char *name_b,
2286                              const char *attr_path,
2287                              struct diff_filespec *one,
2288                              struct diff_filespec *two,
2289                              struct diff_options *o)
2290{
2291        mmfile_t mf1, mf2;
2292        struct checkdiff_t data;
2293
2294        if (!two)
2295                return;
2296
2297        memset(&data, 0, sizeof(data));
2298        data.filename = name_b ? name_b : name_a;
2299        data.lineno = 0;
2300        data.o = o;
2301        data.ws_rule = whitespace_rule(attr_path);
2302        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2303
2304        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2305                die("unable to read files to diff");
2306
2307        /*
2308         * All the other codepaths check both sides, but not checking
2309         * the "old" side here is deliberate.  We are checking the newly
2310         * introduced changes, and as long as the "new" side is text, we
2311         * can and should check what it introduces.
2312         */
2313        if (diff_filespec_is_binary(two))
2314                goto free_and_return;
2315        else {
2316                /* Crazy xdl interfaces.. */
2317                xpparam_t xpp;
2318                xdemitconf_t xecfg;
2319
2320                memset(&xpp, 0, sizeof(xpp));
2321                memset(&xecfg, 0, sizeof(xecfg));
2322                xecfg.ctxlen = 1; /* at least one context line */
2323                xpp.flags = 0;
2324                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2325                              &xpp, &xecfg);
2326
2327                if (data.ws_rule & WS_BLANK_AT_EOF) {
2328                        struct emit_callback ecbdata;
2329                        int blank_at_eof;
2330
2331                        ecbdata.ws_rule = data.ws_rule;
2332                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2333                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2334
2335                        if (blank_at_eof) {
2336                                static char *err;
2337                                if (!err)
2338                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2339                                fprintf(o->file, "%s:%d: %s.\n",
2340                                        data.filename, blank_at_eof, err);
2341                                data.status = 1; /* report errors */
2342                        }
2343                }
2344        }
2345 free_and_return:
2346        diff_free_filespec_data(one);
2347        diff_free_filespec_data(two);
2348        if (data.status)
2349                DIFF_OPT_SET(o, CHECK_FAILED);
2350}
2351
2352struct diff_filespec *alloc_filespec(const char *path)
2353{
2354        int namelen = strlen(path);
2355        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2356
2357        memset(spec, 0, sizeof(*spec));
2358        spec->path = (char *)(spec + 1);
2359        memcpy(spec->path, path, namelen+1);
2360        spec->count = 1;
2361        spec->is_binary = -1;
2362        return spec;
2363}
2364
2365void free_filespec(struct diff_filespec *spec)
2366{
2367        if (!--spec->count) {
2368                diff_free_filespec_data(spec);
2369                free(spec);
2370        }
2371}
2372
2373void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2374                   unsigned short mode)
2375{
2376        if (mode) {
2377                spec->mode = canon_mode(mode);
2378                hashcpy(spec->sha1, sha1);
2379                spec->sha1_valid = !is_null_sha1(sha1);
2380        }
2381}
2382
2383/*
2384 * Given a name and sha1 pair, if the index tells us the file in
2385 * the work tree has that object contents, return true, so that
2386 * prepare_temp_file() does not have to inflate and extract.
2387 */
2388static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2389{
2390        struct cache_entry *ce;
2391        struct stat st;
2392        int pos, len;
2393
2394        /*
2395         * We do not read the cache ourselves here, because the
2396         * benchmark with my previous version that always reads cache
2397         * shows that it makes things worse for diff-tree comparing
2398         * two linux-2.6 kernel trees in an already checked out work
2399         * tree.  This is because most diff-tree comparisons deal with
2400         * only a small number of files, while reading the cache is
2401         * expensive for a large project, and its cost outweighs the
2402         * savings we get by not inflating the object to a temporary
2403         * file.  Practically, this code only helps when we are used
2404         * by diff-cache --cached, which does read the cache before
2405         * calling us.
2406         */
2407        if (!active_cache)
2408                return 0;
2409
2410        /* We want to avoid the working directory if our caller
2411         * doesn't need the data in a normal file, this system
2412         * is rather slow with its stat/open/mmap/close syscalls,
2413         * and the object is contained in a pack file.  The pack
2414         * is probably already open and will be faster to obtain
2415         * the data through than the working directory.  Loose
2416         * objects however would tend to be slower as they need
2417         * to be individually opened and inflated.
2418         */
2419        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2420                return 0;
2421
2422        len = strlen(name);
2423        pos = cache_name_pos(name, len);
2424        if (pos < 0)
2425                return 0;
2426        ce = active_cache[pos];
2427
2428        /*
2429         * This is not the sha1 we are looking for, or
2430         * unreusable because it is not a regular file.
2431         */
2432        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2433                return 0;
2434
2435        /*
2436         * If ce is marked as "assume unchanged", there is no
2437         * guarantee that work tree matches what we are looking for.
2438         */
2439        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2440                return 0;
2441
2442        /*
2443         * If ce matches the file in the work tree, we can reuse it.
2444         */
2445        if (ce_uptodate(ce) ||
2446            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2447                return 1;
2448
2449        return 0;
2450}
2451
2452static int populate_from_stdin(struct diff_filespec *s)
2453{
2454        struct strbuf buf = STRBUF_INIT;
2455        size_t size = 0;
2456
2457        if (strbuf_read(&buf, 0, 0) < 0)
2458                return error("error while reading from stdin %s",
2459                                     strerror(errno));
2460
2461        s->should_munmap = 0;
2462        s->data = strbuf_detach(&buf, &size);
2463        s->size = size;
2464        s->should_free = 1;
2465        return 0;
2466}
2467
2468static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2469{
2470        int len;
2471        char *data = xmalloc(100), *dirty = "";
2472
2473        /* Are we looking at the work tree? */
2474        if (s->dirty_submodule)
2475                dirty = "-dirty";
2476
2477        len = snprintf(data, 100,
2478                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2479        s->data = data;
2480        s->size = len;
2481        s->should_free = 1;
2482        if (size_only) {
2483                s->data = NULL;
2484                free(data);
2485        }
2486        return 0;
2487}
2488
2489/*
2490 * While doing rename detection and pickaxe operation, we may need to
2491 * grab the data for the blob (or file) for our own in-core comparison.
2492 * diff_filespec has data and size fields for this purpose.
2493 */
2494int diff_populate_filespec(struct diff_filespec *s, int size_only)
2495{
2496        int err = 0;
2497        if (!DIFF_FILE_VALID(s))
2498                die("internal error: asking to populate invalid file.");
2499        if (S_ISDIR(s->mode))
2500                return -1;
2501
2502        if (s->data)
2503                return 0;
2504
2505        if (size_only && 0 < s->size)
2506                return 0;
2507
2508        if (S_ISGITLINK(s->mode))
2509                return diff_populate_gitlink(s, size_only);
2510
2511        if (!s->sha1_valid ||
2512            reuse_worktree_file(s->path, s->sha1, 0)) {
2513                struct strbuf buf = STRBUF_INIT;
2514                struct stat st;
2515                int fd;
2516
2517                if (!strcmp(s->path, "-"))
2518                        return populate_from_stdin(s);
2519
2520                if (lstat(s->path, &st) < 0) {
2521                        if (errno == ENOENT) {
2522                        err_empty:
2523                                err = -1;
2524                        empty:
2525                                s->data = (char *)"";
2526                                s->size = 0;
2527                                return err;
2528                        }
2529                }
2530                s->size = xsize_t(st.st_size);
2531                if (!s->size)
2532                        goto empty;
2533                if (S_ISLNK(st.st_mode)) {
2534                        struct strbuf sb = STRBUF_INIT;
2535
2536                        if (strbuf_readlink(&sb, s->path, s->size))
2537                                goto err_empty;
2538                        s->size = sb.len;
2539                        s->data = strbuf_detach(&sb, NULL);
2540                        s->should_free = 1;
2541                        return 0;
2542                }
2543                if (size_only)
2544                        return 0;
2545                fd = open(s->path, O_RDONLY);
2546                if (fd < 0)
2547                        goto err_empty;
2548                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2549                close(fd);
2550                s->should_munmap = 1;
2551
2552                /*
2553                 * Convert from working tree format to canonical git format
2554                 */
2555                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2556                        size_t size = 0;
2557                        munmap(s->data, s->size);
2558                        s->should_munmap = 0;
2559                        s->data = strbuf_detach(&buf, &size);
2560                        s->size = size;
2561                        s->should_free = 1;
2562                }
2563        }
2564        else {
2565                enum object_type type;
2566                if (size_only) {
2567                        type = sha1_object_info(s->sha1, &s->size);
2568                        if (type < 0)
2569                                die("unable to read %s", sha1_to_hex(s->sha1));
2570                } else {
2571                        s->data = read_sha1_file(s->sha1, &type, &s->size);
2572                        if (!s->data)
2573                                die("unable to read %s", sha1_to_hex(s->sha1));
2574                        s->should_free = 1;
2575                }
2576        }
2577        return 0;
2578}
2579
2580void diff_free_filespec_blob(struct diff_filespec *s)
2581{
2582        if (s->should_free)
2583                free(s->data);
2584        else if (s->should_munmap)
2585                munmap(s->data, s->size);
2586
2587        if (s->should_free || s->should_munmap) {
2588                s->should_free = s->should_munmap = 0;
2589                s->data = NULL;
2590        }
2591}
2592
2593void diff_free_filespec_data(struct diff_filespec *s)
2594{
2595        diff_free_filespec_blob(s);
2596        free(s->cnt_data);
2597        s->cnt_data = NULL;
2598}
2599
2600static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2601                           void *blob,
2602                           unsigned long size,
2603                           const unsigned char *sha1,
2604                           int mode)
2605{
2606        int fd;
2607        struct strbuf buf = STRBUF_INIT;
2608        struct strbuf template = STRBUF_INIT;
2609        char *path_dup = xstrdup(path);
2610        const char *base = basename(path_dup);
2611
2612        /* Generate "XXXXXX_basename.ext" */
2613        strbuf_addstr(&template, "XXXXXX_");
2614        strbuf_addstr(&template, base);
2615
2616        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2617                        strlen(base) + 1);
2618        if (fd < 0)
2619                die_errno("unable to create temp-file");
2620        if (convert_to_working_tree(path,
2621                        (const char *)blob, (size_t)size, &buf)) {
2622                blob = buf.buf;
2623                size = buf.len;
2624        }
2625        if (write_in_full(fd, blob, size) != size)
2626                die_errno("unable to write temp-file");
2627        close(fd);
2628        temp->name = temp->tmp_path;
2629        strcpy(temp->hex, sha1_to_hex(sha1));
2630        temp->hex[40] = 0;
2631        sprintf(temp->mode, "%06o", mode);
2632        strbuf_release(&buf);
2633        strbuf_release(&template);
2634        free(path_dup);
2635}
2636
2637static struct diff_tempfile *prepare_temp_file(const char *name,
2638                struct diff_filespec *one)
2639{
2640        struct diff_tempfile *temp = claim_diff_tempfile();
2641
2642        if (!DIFF_FILE_VALID(one)) {
2643        not_a_valid_file:
2644                /* A '-' entry produces this for file-2, and
2645                 * a '+' entry produces this for file-1.
2646                 */
2647                temp->name = "/dev/null";
2648                strcpy(temp->hex, ".");
2649                strcpy(temp->mode, ".");
2650                return temp;
2651        }
2652
2653        if (!remove_tempfile_installed) {
2654                atexit(remove_tempfile);
2655                sigchain_push_common(remove_tempfile_on_signal);
2656                remove_tempfile_installed = 1;
2657        }
2658
2659        if (!one->sha1_valid ||
2660            reuse_worktree_file(name, one->sha1, 1)) {
2661                struct stat st;
2662                if (lstat(name, &st) < 0) {
2663                        if (errno == ENOENT)
2664                                goto not_a_valid_file;
2665                        die_errno("stat(%s)", name);
2666                }
2667                if (S_ISLNK(st.st_mode)) {
2668                        struct strbuf sb = STRBUF_INIT;
2669                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2670                                die_errno("readlink(%s)", name);
2671                        prep_temp_blob(name, temp, sb.buf, sb.len,
2672                                       (one->sha1_valid ?
2673                                        one->sha1 : null_sha1),
2674                                       (one->sha1_valid ?
2675                                        one->mode : S_IFLNK));
2676                        strbuf_release(&sb);
2677                }
2678                else {
2679                        /* we can borrow from the file in the work tree */
2680                        temp->name = name;
2681                        if (!one->sha1_valid)
2682                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2683                        else
2684                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2685                        /* Even though we may sometimes borrow the
2686                         * contents from the work tree, we always want
2687                         * one->mode.  mode is trustworthy even when
2688                         * !(one->sha1_valid), as long as
2689                         * DIFF_FILE_VALID(one).
2690                         */
2691                        sprintf(temp->mode, "%06o", one->mode);
2692                }
2693                return temp;
2694        }
2695        else {
2696                if (diff_populate_filespec(one, 0))
2697                        die("cannot read data blob for %s", one->path);
2698                prep_temp_blob(name, temp, one->data, one->size,
2699                               one->sha1, one->mode);
2700        }
2701        return temp;
2702}
2703
2704/* An external diff command takes:
2705 *
2706 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2707 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2708 *
2709 */
2710static void run_external_diff(const char *pgm,
2711                              const char *name,
2712                              const char *other,
2713                              struct diff_filespec *one,
2714                              struct diff_filespec *two,
2715                              const char *xfrm_msg,
2716                              int complete_rewrite)
2717{
2718        const char *spawn_arg[10];
2719        int retval;
2720        const char **arg = &spawn_arg[0];
2721
2722        if (one && two) {
2723                struct diff_tempfile *temp_one, *temp_two;
2724                const char *othername = (other ? other : name);
2725                temp_one = prepare_temp_file(name, one);
2726                temp_two = prepare_temp_file(othername, two);
2727                *arg++ = pgm;
2728                *arg++ = name;
2729                *arg++ = temp_one->name;
2730                *arg++ = temp_one->hex;
2731                *arg++ = temp_one->mode;
2732                *arg++ = temp_two->name;
2733                *arg++ = temp_two->hex;
2734                *arg++ = temp_two->mode;
2735                if (other) {
2736                        *arg++ = other;
2737                        *arg++ = xfrm_msg;
2738                }
2739        } else {
2740                *arg++ = pgm;
2741                *arg++ = name;
2742        }
2743        *arg = NULL;
2744        fflush(NULL);
2745        retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2746        remove_tempfile();
2747        if (retval) {
2748                fprintf(stderr, "external diff died, stopping at %s.\n", name);
2749                exit(1);
2750        }
2751}
2752
2753static int similarity_index(struct diff_filepair *p)
2754{
2755        return p->score * 100 / MAX_SCORE;
2756}
2757
2758static void fill_metainfo(struct strbuf *msg,
2759                          const char *name,
2760                          const char *other,
2761                          struct diff_filespec *one,
2762                          struct diff_filespec *two,
2763                          struct diff_options *o,
2764                          struct diff_filepair *p,
2765                          int *must_show_header,
2766                          int use_color)
2767{
2768        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2769        const char *reset = diff_get_color(use_color, DIFF_RESET);
2770        struct strbuf *msgbuf;
2771        char *line_prefix = "";
2772
2773        *must_show_header = 1;
2774        if (o->output_prefix) {
2775                msgbuf = o->output_prefix(o, o->output_prefix_data);
2776                line_prefix = msgbuf->buf;
2777        }
2778        strbuf_init(msg, PATH_MAX * 2 + 300);
2779        switch (p->status) {
2780        case DIFF_STATUS_COPIED:
2781                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2782                            line_prefix, set, similarity_index(p));
2783                strbuf_addf(msg, "%s\n%s%scopy from ",
2784                            reset,  line_prefix, set);
2785                quote_c_style(name, msg, NULL, 0);
2786                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2787                quote_c_style(other, msg, NULL, 0);
2788                strbuf_addf(msg, "%s\n", reset);
2789                break;
2790        case DIFF_STATUS_RENAMED:
2791                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2792                            line_prefix, set, similarity_index(p));
2793                strbuf_addf(msg, "%s\n%s%srename from ",
2794                            reset, line_prefix, set);
2795                quote_c_style(name, msg, NULL, 0);
2796                strbuf_addf(msg, "%s\n%s%srename to ",
2797                            reset, line_prefix, set);
2798                quote_c_style(other, msg, NULL, 0);
2799                strbuf_addf(msg, "%s\n", reset);
2800                break;
2801        case DIFF_STATUS_MODIFIED:
2802                if (p->score) {
2803                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2804                                    line_prefix,
2805                                    set, similarity_index(p), reset);
2806                        break;
2807                }
2808                /* fallthru */
2809        default:
2810                *must_show_header = 0;
2811        }
2812        if (one && two && hashcmp(one->sha1, two->sha1)) {
2813                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2814
2815                if (DIFF_OPT_TST(o, BINARY)) {
2816                        mmfile_t mf;
2817                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2818                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2819                                abbrev = 40;
2820                }
2821                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2822                            find_unique_abbrev(one->sha1, abbrev));
2823                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2824                if (one->mode == two->mode)
2825                        strbuf_addf(msg, " %06o", one->mode);
2826                strbuf_addf(msg, "%s\n", reset);
2827        }
2828}
2829
2830static void run_diff_cmd(const char *pgm,
2831                         const char *name,
2832                         const char *other,
2833                         const char *attr_path,
2834                         struct diff_filespec *one,
2835                         struct diff_filespec *two,
2836                         struct strbuf *msg,
2837                         struct diff_options *o,
2838                         struct diff_filepair *p)
2839{
2840        const char *xfrm_msg = NULL;
2841        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
2842        int must_show_header = 0;
2843
2844        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2845                pgm = NULL;
2846        else {
2847                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
2848                if (drv && drv->external)
2849                        pgm = drv->external;
2850        }
2851
2852        if (msg) {
2853                /*
2854                 * don't use colors when the header is intended for an
2855                 * external diff driver
2856                 */
2857                fill_metainfo(msg, name, other, one, two, o, p,
2858                              &must_show_header,
2859                              want_color(o->use_color) && !pgm);
2860                xfrm_msg = msg->len ? msg->buf : NULL;
2861        }
2862
2863        if (pgm) {
2864                run_external_diff(pgm, name, other, one, two, xfrm_msg,
2865                                  complete_rewrite);
2866                return;
2867        }
2868        if (one && two)
2869                builtin_diff(name, other ? other : name,
2870                             one, two, xfrm_msg, must_show_header,
2871                             o, complete_rewrite);
2872        else
2873                fprintf(o->file, "* Unmerged path %s\n", name);
2874}
2875
2876static void diff_fill_sha1_info(struct diff_filespec *one)
2877{
2878        if (DIFF_FILE_VALID(one)) {
2879                if (!one->sha1_valid) {
2880                        struct stat st;
2881                        if (!strcmp(one->path, "-")) {
2882                                hashcpy(one->sha1, null_sha1);
2883                                return;
2884                        }
2885                        if (lstat(one->path, &st) < 0)
2886                                die_errno("stat '%s'", one->path);
2887                        if (index_path(one->sha1, one->path, &st, 0))
2888                                die("cannot hash %s", one->path);
2889                }
2890        }
2891        else
2892                hashclr(one->sha1);
2893}
2894
2895static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2896{
2897        /* Strip the prefix but do not molest /dev/null and absolute paths */
2898        if (*namep && **namep != '/') {
2899                *namep += prefix_length;
2900                if (**namep == '/')
2901                        ++*namep;
2902        }
2903        if (*otherp && **otherp != '/') {
2904                *otherp += prefix_length;
2905                if (**otherp == '/')
2906                        ++*otherp;
2907        }
2908}
2909
2910static void run_diff(struct diff_filepair *p, struct diff_options *o)
2911{
2912        const char *pgm = external_diff();
2913        struct strbuf msg;
2914        struct diff_filespec *one = p->one;
2915        struct diff_filespec *two = p->two;
2916        const char *name;
2917        const char *other;
2918        const char *attr_path;
2919
2920        name  = p->one->path;
2921        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2922        attr_path = name;
2923        if (o->prefix_length)
2924                strip_prefix(o->prefix_length, &name, &other);
2925
2926        if (DIFF_PAIR_UNMERGED(p)) {
2927                run_diff_cmd(pgm, name, NULL, attr_path,
2928                             NULL, NULL, NULL, o, p);
2929                return;
2930        }
2931
2932        diff_fill_sha1_info(one);
2933        diff_fill_sha1_info(two);
2934
2935        if (!pgm &&
2936            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2937            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2938                /*
2939                 * a filepair that changes between file and symlink
2940                 * needs to be split into deletion and creation.
2941                 */
2942                struct diff_filespec *null = alloc_filespec(two->path);
2943                run_diff_cmd(NULL, name, other, attr_path,
2944                             one, null, &msg, o, p);
2945                free(null);
2946                strbuf_release(&msg);
2947
2948                null = alloc_filespec(one->path);
2949                run_diff_cmd(NULL, name, other, attr_path,
2950                             null, two, &msg, o, p);
2951                free(null);
2952        }
2953        else
2954                run_diff_cmd(pgm, name, other, attr_path,
2955                             one, two, &msg, o, p);
2956
2957        strbuf_release(&msg);
2958}
2959
2960static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2961                         struct diffstat_t *diffstat)
2962{
2963        const char *name;
2964        const char *other;
2965        int complete_rewrite = 0;
2966
2967        if (DIFF_PAIR_UNMERGED(p)) {
2968                /* unmerged */
2969                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2970                return;
2971        }
2972
2973        name = p->one->path;
2974        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2975
2976        if (o->prefix_length)
2977                strip_prefix(o->prefix_length, &name, &other);
2978
2979        diff_fill_sha1_info(p->one);
2980        diff_fill_sha1_info(p->two);
2981
2982        if (p->status == DIFF_STATUS_MODIFIED && p->score)
2983                complete_rewrite = 1;
2984        builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2985}
2986
2987static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2988{
2989        const char *name;
2990        const char *other;
2991        const char *attr_path;
2992
2993        if (DIFF_PAIR_UNMERGED(p)) {
2994                /* unmerged */
2995                return;
2996        }
2997
2998        name = p->one->path;
2999        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3000        attr_path = other ? other : name;
3001
3002        if (o->prefix_length)
3003                strip_prefix(o->prefix_length, &name, &other);
3004
3005        diff_fill_sha1_info(p->one);
3006        diff_fill_sha1_info(p->two);
3007
3008        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3009}
3010
3011void diff_setup(struct diff_options *options)
3012{
3013        memcpy(options, &default_diff_options, sizeof(*options));
3014
3015        options->file = stdout;
3016
3017        options->line_termination = '\n';
3018        options->break_opt = -1;
3019        options->rename_limit = -1;
3020        options->dirstat_permille = diff_dirstat_permille_default;
3021        options->context = 3;
3022
3023        options->change = diff_change;
3024        options->add_remove = diff_addremove;
3025        options->use_color = diff_use_color_default;
3026        options->detect_rename = diff_detect_rename_default;
3027
3028        if (diff_no_prefix) {
3029                options->a_prefix = options->b_prefix = "";
3030        } else if (!diff_mnemonic_prefix) {
3031                options->a_prefix = "a/";
3032                options->b_prefix = "b/";
3033        }
3034}
3035
3036int diff_setup_done(struct diff_options *options)
3037{
3038        int count = 0;
3039
3040        if (options->output_format & DIFF_FORMAT_NAME)
3041                count++;
3042        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3043                count++;
3044        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3045                count++;
3046        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3047                count++;
3048        if (count > 1)
3049                die("--name-only, --name-status, --check and -s are mutually exclusive");
3050
3051        /*
3052         * Most of the time we can say "there are changes"
3053         * only by checking if there are changed paths, but
3054         * --ignore-whitespace* options force us to look
3055         * inside contents.
3056         */
3057
3058        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3059            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3060            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3061                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3062        else
3063                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3064
3065        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3066                options->detect_rename = DIFF_DETECT_COPY;
3067
3068        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3069                options->prefix = NULL;
3070        if (options->prefix)
3071                options->prefix_length = strlen(options->prefix);
3072        else
3073                options->prefix_length = 0;
3074
3075        if (options->output_format & (DIFF_FORMAT_NAME |
3076                                      DIFF_FORMAT_NAME_STATUS |
3077                                      DIFF_FORMAT_CHECKDIFF |
3078                                      DIFF_FORMAT_NO_OUTPUT))
3079                options->output_format &= ~(DIFF_FORMAT_RAW |
3080                                            DIFF_FORMAT_NUMSTAT |
3081                                            DIFF_FORMAT_DIFFSTAT |
3082                                            DIFF_FORMAT_SHORTSTAT |
3083                                            DIFF_FORMAT_DIRSTAT |
3084                                            DIFF_FORMAT_SUMMARY |
3085                                            DIFF_FORMAT_PATCH);
3086
3087        /*
3088         * These cases always need recursive; we do not drop caller-supplied
3089         * recursive bits for other formats here.
3090         */
3091        if (options->output_format & (DIFF_FORMAT_PATCH |
3092                                      DIFF_FORMAT_NUMSTAT |
3093                                      DIFF_FORMAT_DIFFSTAT |
3094                                      DIFF_FORMAT_SHORTSTAT |
3095                                      DIFF_FORMAT_DIRSTAT |
3096                                      DIFF_FORMAT_SUMMARY |
3097                                      DIFF_FORMAT_CHECKDIFF))
3098                DIFF_OPT_SET(options, RECURSIVE);
3099        /*
3100         * Also pickaxe would not work very well if you do not say recursive
3101         */
3102        if (options->pickaxe)
3103                DIFF_OPT_SET(options, RECURSIVE);
3104        /*
3105         * When patches are generated, submodules diffed against the work tree
3106         * must be checked for dirtiness too so it can be shown in the output
3107         */
3108        if (options->output_format & DIFF_FORMAT_PATCH)
3109                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3110
3111        if (options->detect_rename && options->rename_limit < 0)
3112                options->rename_limit = diff_rename_limit_default;
3113        if (options->setup & DIFF_SETUP_USE_CACHE) {
3114                if (!active_cache)
3115                        /* read-cache does not die even when it fails
3116                         * so it is safe for us to do this here.  Also
3117                         * it does not smudge active_cache or active_nr
3118                         * when it fails, so we do not have to worry about
3119                         * cleaning it up ourselves either.
3120                         */
3121                        read_cache();
3122        }
3123        if (options->abbrev <= 0 || 40 < options->abbrev)
3124                options->abbrev = 40; /* full */
3125
3126        /*
3127         * It does not make sense to show the first hit we happened
3128         * to have found.  It does not make sense not to return with
3129         * exit code in such a case either.
3130         */
3131        if (DIFF_OPT_TST(options, QUICK)) {
3132                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3133                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3134        }
3135
3136        return 0;
3137}
3138
3139static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3140{
3141        char c, *eq;
3142        int len;
3143
3144        if (*arg != '-')
3145                return 0;
3146        c = *++arg;
3147        if (!c)
3148                return 0;
3149        if (c == arg_short) {
3150                c = *++arg;
3151                if (!c)
3152                        return 1;
3153                if (val && isdigit(c)) {
3154                        char *end;
3155                        int n = strtoul(arg, &end, 10);
3156                        if (*end)
3157                                return 0;
3158                        *val = n;
3159                        return 1;
3160                }
3161                return 0;
3162        }
3163        if (c != '-')
3164                return 0;
3165        arg++;
3166        eq = strchr(arg, '=');
3167        if (eq)
3168                len = eq - arg;
3169        else
3170                len = strlen(arg);
3171        if (!len || strncmp(arg, arg_long, len))
3172                return 0;
3173        if (eq) {
3174                int n;
3175                char *end;
3176                if (!isdigit(*++eq))
3177                        return 0;
3178                n = strtoul(eq, &end, 10);
3179                if (*end)
3180                        return 0;
3181                *val = n;
3182        }
3183        return 1;
3184}
3185
3186static int diff_scoreopt_parse(const char *opt);
3187
3188static inline int short_opt(char opt, const char **argv,
3189                            const char **optarg)
3190{
3191        const char *arg = argv[0];
3192        if (arg[0] != '-' || arg[1] != opt)
3193                return 0;
3194        if (arg[2] != '\0') {
3195                *optarg = arg + 2;
3196                return 1;
3197        }
3198        if (!argv[1])
3199                die("Option '%c' requires a value", opt);
3200        *optarg = argv[1];
3201        return 2;
3202}
3203
3204int parse_long_opt(const char *opt, const char **argv,
3205                   const char **optarg)
3206{
3207        const char *arg = argv[0];
3208        if (arg[0] != '-' || arg[1] != '-')
3209                return 0;
3210        arg += strlen("--");
3211        if (prefixcmp(arg, opt))
3212                return 0;
3213        arg += strlen(opt);
3214        if (*arg == '=') { /* sticked form: --option=value */
3215                *optarg = arg + 1;
3216                return 1;
3217        }
3218        if (*arg != '\0')
3219                return 0;
3220        /* separate form: --option value */
3221        if (!argv[1])
3222                die("Option '--%s' requires a value", opt);
3223        *optarg = argv[1];
3224        return 2;
3225}
3226
3227static int stat_opt(struct diff_options *options, const char **av)
3228{
3229        const char *arg = av[0];
3230        char *end;
3231        int width = options->stat_width;
3232        int name_width = options->stat_name_width;
3233        int count = options->stat_count;
3234        int argcount = 1;
3235
3236        arg += strlen("--stat");
3237        end = (char *)arg;
3238
3239        switch (*arg) {
3240        case '-':
3241                if (!prefixcmp(arg, "-width")) {
3242                        arg += strlen("-width");
3243                        if (*arg == '=')
3244                                width = strtoul(arg + 1, &end, 10);
3245                        else if (!*arg && !av[1])
3246                                die("Option '--stat-width' requires a value");
3247                        else if (!*arg) {
3248                                width = strtoul(av[1], &end, 10);
3249                                argcount = 2;
3250                        }
3251                } else if (!prefixcmp(arg, "-name-width")) {
3252                        arg += strlen("-name-width");
3253                        if (*arg == '=')
3254                                name_width = strtoul(arg + 1, &end, 10);
3255                        else if (!*arg && !av[1])
3256                                die("Option '--stat-name-width' requires a value");
3257                        else if (!*arg) {
3258                                name_width = strtoul(av[1], &end, 10);
3259                                argcount = 2;
3260                        }
3261                } else if (!prefixcmp(arg, "-count")) {
3262                        arg += strlen("-count");
3263                        if (*arg == '=')
3264                                count = strtoul(arg + 1, &end, 10);
3265                        else if (!*arg && !av[1])
3266                                die("Option '--stat-count' requires a value");
3267                        else if (!*arg) {
3268                                count = strtoul(av[1], &end, 10);
3269                                argcount = 2;
3270                        }
3271                }
3272                break;
3273        case '=':
3274                width = strtoul(arg+1, &end, 10);
3275                if (*end == ',')
3276                        name_width = strtoul(end+1, &end, 10);
3277                if (*end == ',')
3278                        count = strtoul(end+1, &end, 10);
3279        }
3280
3281        /* Important! This checks all the error cases! */
3282        if (*end)
3283                return 0;
3284        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3285        options->stat_name_width = name_width;
3286        options->stat_width = width;
3287        options->stat_count = count;
3288        return argcount;
3289}
3290
3291static int parse_dirstat_opt(struct diff_options *options, const char *params)
3292{
3293        struct strbuf errmsg = STRBUF_INIT;
3294        if (parse_dirstat_params(options, params, &errmsg))
3295                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3296                    errmsg.buf);
3297        strbuf_release(&errmsg);
3298        /*
3299         * The caller knows a dirstat-related option is given from the command
3300         * line; allow it to say "return this_function();"
3301         */
3302        options->output_format |= DIFF_FORMAT_DIRSTAT;
3303        return 1;
3304}
3305
3306int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3307{
3308        const char *arg = av[0];
3309        const char *optarg;
3310        int argcount;
3311
3312        /* Output format options */
3313        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3314                options->output_format |= DIFF_FORMAT_PATCH;
3315        else if (opt_arg(arg, 'U', "unified", &options->context))
3316                options->output_format |= DIFF_FORMAT_PATCH;
3317        else if (!strcmp(arg, "--raw"))
3318                options->output_format |= DIFF_FORMAT_RAW;
3319        else if (!strcmp(arg, "--patch-with-raw"))
3320                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3321        else if (!strcmp(arg, "--numstat"))
3322                options->output_format |= DIFF_FORMAT_NUMSTAT;
3323        else if (!strcmp(arg, "--shortstat"))
3324                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3325        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3326                return parse_dirstat_opt(options, "");
3327        else if (!prefixcmp(arg, "-X"))
3328                return parse_dirstat_opt(options, arg + 2);
3329        else if (!prefixcmp(arg, "--dirstat="))
3330                return parse_dirstat_opt(options, arg + 10);
3331        else if (!strcmp(arg, "--cumulative"))
3332                return parse_dirstat_opt(options, "cumulative");
3333        else if (!strcmp(arg, "--dirstat-by-file"))
3334                return parse_dirstat_opt(options, "files");
3335        else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3336                parse_dirstat_opt(options, "files");
3337                return parse_dirstat_opt(options, arg + 18);
3338        }
3339        else if (!strcmp(arg, "--check"))
3340                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3341        else if (!strcmp(arg, "--summary"))
3342                options->output_format |= DIFF_FORMAT_SUMMARY;
3343        else if (!strcmp(arg, "--patch-with-stat"))
3344                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3345        else if (!strcmp(arg, "--name-only"))
3346                options->output_format |= DIFF_FORMAT_NAME;
3347        else if (!strcmp(arg, "--name-status"))
3348                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3349        else if (!strcmp(arg, "-s"))
3350                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3351        else if (!prefixcmp(arg, "--stat"))
3352                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3353                return stat_opt(options, av);
3354
3355        /* renames options */
3356        else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3357                 !strcmp(arg, "--break-rewrites")) {
3358                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3359                        return error("invalid argument to -B: %s", arg+2);
3360        }
3361        else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3362                 !strcmp(arg, "--find-renames")) {
3363                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3364                        return error("invalid argument to -M: %s", arg+2);
3365                options->detect_rename = DIFF_DETECT_RENAME;
3366        }
3367        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3368                options->irreversible_delete = 1;
3369        }
3370        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3371                 !strcmp(arg, "--find-copies")) {
3372                if (options->detect_rename == DIFF_DETECT_COPY)
3373                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3374                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3375                        return error("invalid argument to -C: %s", arg+2);
3376                options->detect_rename = DIFF_DETECT_COPY;
3377        }
3378        else if (!strcmp(arg, "--no-renames"))
3379                options->detect_rename = 0;
3380        else if (!strcmp(arg, "--relative"))
3381                DIFF_OPT_SET(options, RELATIVE_NAME);
3382        else if (!prefixcmp(arg, "--relative=")) {
3383                DIFF_OPT_SET(options, RELATIVE_NAME);
3384                options->prefix = arg + 11;
3385        }
3386
3387        /* xdiff options */
3388        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3389                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3390        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3391                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3392        else if (!strcmp(arg, "--ignore-space-at-eol"))
3393                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3394        else if (!strcmp(arg, "--patience"))
3395                DIFF_XDL_SET(options, PATIENCE_DIFF);
3396        else if (!strcmp(arg, "--histogram"))
3397                DIFF_XDL_SET(options, HISTOGRAM_DIFF);
3398
3399        /* flags options */
3400        else if (!strcmp(arg, "--binary")) {
3401                options->output_format |= DIFF_FORMAT_PATCH;
3402                DIFF_OPT_SET(options, BINARY);
3403        }
3404        else if (!strcmp(arg, "--full-index"))
3405                DIFF_OPT_SET(options, FULL_INDEX);
3406        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3407                DIFF_OPT_SET(options, TEXT);
3408        else if (!strcmp(arg, "-R"))
3409                DIFF_OPT_SET(options, REVERSE_DIFF);
3410        else if (!strcmp(arg, "--find-copies-harder"))
3411                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3412        else if (!strcmp(arg, "--follow"))
3413                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3414        else if (!strcmp(arg, "--color"))
3415                options->use_color = 1;
3416        else if (!prefixcmp(arg, "--color=")) {
3417                int value = git_config_colorbool(NULL, arg+8);
3418                if (value < 0)
3419                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3420                options->use_color = value;
3421        }
3422        else if (!strcmp(arg, "--no-color"))
3423                options->use_color = 0;
3424        else if (!strcmp(arg, "--color-words")) {
3425                options->use_color = 1;
3426                options->word_diff = DIFF_WORDS_COLOR;
3427        }
3428        else if (!prefixcmp(arg, "--color-words=")) {
3429                options->use_color = 1;
3430                options->word_diff = DIFF_WORDS_COLOR;
3431                options->word_regex = arg + 14;
3432        }
3433        else if (!strcmp(arg, "--word-diff")) {
3434                if (options->word_diff == DIFF_WORDS_NONE)
3435                        options->word_diff = DIFF_WORDS_PLAIN;
3436        }
3437        else if (!prefixcmp(arg, "--word-diff=")) {
3438                const char *type = arg + 12;
3439                if (!strcmp(type, "plain"))
3440                        options->word_diff = DIFF_WORDS_PLAIN;
3441                else if (!strcmp(type, "color")) {
3442                        options->use_color = 1;
3443                        options->word_diff = DIFF_WORDS_COLOR;
3444                }
3445                else if (!strcmp(type, "porcelain"))
3446                        options->word_diff = DIFF_WORDS_PORCELAIN;
3447                else if (!strcmp(type, "none"))
3448                        options->word_diff = DIFF_WORDS_NONE;
3449                else
3450                        die("bad --word-diff argument: %s", type);
3451        }
3452        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3453                if (options->word_diff == DIFF_WORDS_NONE)
3454                        options->word_diff = DIFF_WORDS_PLAIN;
3455                options->word_regex = optarg;
3456                return argcount;
3457        }
3458        else if (!strcmp(arg, "--exit-code"))
3459                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3460        else if (!strcmp(arg, "--quiet"))
3461                DIFF_OPT_SET(options, QUICK);
3462        else if (!strcmp(arg, "--ext-diff"))
3463                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3464        else if (!strcmp(arg, "--no-ext-diff"))
3465                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3466        else if (!strcmp(arg, "--textconv"))
3467                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3468        else if (!strcmp(arg, "--no-textconv"))
3469                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3470        else if (!strcmp(arg, "--ignore-submodules")) {
3471                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3472                handle_ignore_submodules_arg(options, "all");
3473        } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3474                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3475                handle_ignore_submodules_arg(options, arg + 20);
3476        } else if (!strcmp(arg, "--submodule"))
3477                DIFF_OPT_SET(options, SUBMODULE_LOG);
3478        else if (!prefixcmp(arg, "--submodule=")) {
3479                if (!strcmp(arg + 12, "log"))
3480                        DIFF_OPT_SET(options, SUBMODULE_LOG);
3481        }
3482
3483        /* misc options */
3484        else if (!strcmp(arg, "-z"))
3485                options->line_termination = 0;
3486        else if ((argcount = short_opt('l', av, &optarg))) {
3487                options->rename_limit = strtoul(optarg, NULL, 10);
3488                return argcount;
3489        }
3490        else if ((argcount = short_opt('S', av, &optarg))) {
3491                options->pickaxe = optarg;
3492                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3493                return argcount;
3494        } else if ((argcount = short_opt('G', av, &optarg))) {
3495                options->pickaxe = optarg;
3496                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3497                return argcount;
3498        }
3499        else if (!strcmp(arg, "--pickaxe-all"))
3500                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3501        else if (!strcmp(arg, "--pickaxe-regex"))
3502                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3503        else if ((argcount = short_opt('O', av, &optarg))) {
3504                options->orderfile = optarg;
3505                return argcount;
3506        }
3507        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3508                options->filter = optarg;
3509                return argcount;
3510        }
3511        else if (!strcmp(arg, "--abbrev"))
3512                options->abbrev = DEFAULT_ABBREV;
3513        else if (!prefixcmp(arg, "--abbrev=")) {
3514                options->abbrev = strtoul(arg + 9, NULL, 10);
3515                if (options->abbrev < MINIMUM_ABBREV)
3516                        options->abbrev = MINIMUM_ABBREV;
3517                else if (40 < options->abbrev)
3518                        options->abbrev = 40;
3519        }
3520        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3521                options->a_prefix = optarg;
3522                return argcount;
3523        }
3524        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3525                options->b_prefix = optarg;
3526                return argcount;
3527        }
3528        else if (!strcmp(arg, "--no-prefix"))
3529                options->a_prefix = options->b_prefix = "";
3530        else if (opt_arg(arg, '\0', "inter-hunk-context",
3531                         &options->interhunkcontext))
3532                ;
3533        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3534                options->file = fopen(optarg, "w");
3535                if (!options->file)
3536                        die_errno("Could not open '%s'", optarg);
3537                options->close_file = 1;
3538                return argcount;
3539        } else
3540                return 0;
3541        return 1;
3542}
3543
3544int parse_rename_score(const char **cp_p)
3545{
3546        unsigned long num, scale;
3547        int ch, dot;
3548        const char *cp = *cp_p;
3549
3550        num = 0;
3551        scale = 1;
3552        dot = 0;
3553        for (;;) {
3554                ch = *cp;
3555                if ( !dot && ch == '.' ) {
3556                        scale = 1;
3557                        dot = 1;
3558                } else if ( ch == '%' ) {
3559                        scale = dot ? scale*100 : 100;
3560                        cp++;   /* % is always at the end */
3561                        break;
3562                } else if ( ch >= '0' && ch <= '9' ) {
3563                        if ( scale < 100000 ) {
3564                                scale *= 10;
3565                                num = (num*10) + (ch-'0');
3566                        }
3567                } else {
3568                        break;
3569                }
3570                cp++;
3571        }
3572        *cp_p = cp;
3573
3574        /* user says num divided by scale and we say internally that
3575         * is MAX_SCORE * num / scale.
3576         */
3577        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3578}
3579
3580static int diff_scoreopt_parse(const char *opt)
3581{
3582        int opt1, opt2, cmd;
3583
3584        if (*opt++ != '-')
3585                return -1;
3586        cmd = *opt++;
3587        if (cmd == '-') {
3588                /* convert the long-form arguments into short-form versions */
3589                if (!prefixcmp(opt, "break-rewrites")) {
3590                        opt += strlen("break-rewrites");
3591                        if (*opt == 0 || *opt++ == '=')
3592                                cmd = 'B';
3593                } else if (!prefixcmp(opt, "find-copies")) {
3594                        opt += strlen("find-copies");
3595                        if (*opt == 0 || *opt++ == '=')
3596                                cmd = 'C';
3597                } else if (!prefixcmp(opt, "find-renames")) {
3598                        opt += strlen("find-renames");
3599                        if (*opt == 0 || *opt++ == '=')
3600                                cmd = 'M';
3601                }
3602        }
3603        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3604                return -1; /* that is not a -M, -C nor -B option */
3605
3606        opt1 = parse_rename_score(&opt);
3607        if (cmd != 'B')
3608                opt2 = 0;
3609        else {
3610                if (*opt == 0)
3611                        opt2 = 0;
3612                else if (*opt != '/')
3613                        return -1; /* we expect -B80/99 or -B80 */
3614                else {
3615                        opt++;
3616                        opt2 = parse_rename_score(&opt);
3617                }
3618        }
3619        if (*opt != 0)
3620                return -1;
3621        return opt1 | (opt2 << 16);
3622}
3623
3624struct diff_queue_struct diff_queued_diff;
3625
3626void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3627{
3628        if (queue->alloc <= queue->nr) {
3629                queue->alloc = alloc_nr(queue->alloc);
3630                queue->queue = xrealloc(queue->queue,
3631                                        sizeof(dp) * queue->alloc);
3632        }
3633        queue->queue[queue->nr++] = dp;
3634}
3635
3636struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3637                                 struct diff_filespec *one,
3638                                 struct diff_filespec *two)
3639{
3640        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3641        dp->one = one;
3642        dp->two = two;
3643        if (queue)
3644                diff_q(queue, dp);
3645        return dp;
3646}
3647
3648void diff_free_filepair(struct diff_filepair *p)
3649{
3650        free_filespec(p->one);
3651        free_filespec(p->two);
3652        free(p);
3653}
3654
3655/* This is different from find_unique_abbrev() in that
3656 * it stuffs the result with dots for alignment.
3657 */
3658const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3659{
3660        int abblen;
3661        const char *abbrev;
3662        if (len == 40)
3663                return sha1_to_hex(sha1);
3664
3665        abbrev = find_unique_abbrev(sha1, len);
3666        abblen = strlen(abbrev);
3667        if (abblen < 37) {
3668                static char hex[41];
3669                if (len < abblen && abblen <= len + 2)
3670                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3671                else
3672                        sprintf(hex, "%s...", abbrev);
3673                return hex;
3674        }
3675        return sha1_to_hex(sha1);
3676}
3677
3678static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3679{
3680        int line_termination = opt->line_termination;
3681        int inter_name_termination = line_termination ? '\t' : '\0';
3682        if (opt->output_prefix) {
3683                struct strbuf *msg = NULL;
3684                msg = opt->output_prefix(opt, opt->output_prefix_data);
3685                fprintf(opt->file, "%s", msg->buf);
3686        }
3687
3688        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3689                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3690                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
3691                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3692        }
3693        if (p->score) {
3694                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3695                        inter_name_termination);
3696        } else {
3697                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3698        }
3699
3700        if (p->status == DIFF_STATUS_COPIED ||
3701            p->status == DIFF_STATUS_RENAMED) {
3702                const char *name_a, *name_b;
3703                name_a = p->one->path;
3704                name_b = p->two->path;
3705                strip_prefix(opt->prefix_length, &name_a, &name_b);
3706                write_name_quoted(name_a, opt->file, inter_name_termination);
3707                write_name_quoted(name_b, opt->file, line_termination);
3708        } else {
3709                const char *name_a, *name_b;
3710                name_a = p->one->mode ? p->one->path : p->two->path;
3711                name_b = NULL;
3712                strip_prefix(opt->prefix_length, &name_a, &name_b);
3713                write_name_quoted(name_a, opt->file, line_termination);
3714        }
3715}
3716
3717int diff_unmodified_pair(struct diff_filepair *p)
3718{
3719        /* This function is written stricter than necessary to support
3720         * the currently implemented transformers, but the idea is to
3721         * let transformers to produce diff_filepairs any way they want,
3722         * and filter and clean them up here before producing the output.
3723         */
3724        struct diff_filespec *one = p->one, *two = p->two;
3725
3726        if (DIFF_PAIR_UNMERGED(p))
3727                return 0; /* unmerged is interesting */
3728
3729        /* deletion, addition, mode or type change
3730         * and rename are all interesting.
3731         */
3732        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3733            DIFF_PAIR_MODE_CHANGED(p) ||
3734            strcmp(one->path, two->path))
3735                return 0;
3736
3737        /* both are valid and point at the same path.  that is, we are
3738         * dealing with a change.
3739         */
3740        if (one->sha1_valid && two->sha1_valid &&
3741            !hashcmp(one->sha1, two->sha1) &&
3742            !one->dirty_submodule && !two->dirty_submodule)
3743                return 1; /* no change */
3744        if (!one->sha1_valid && !two->sha1_valid)
3745                return 1; /* both look at the same file on the filesystem. */
3746        return 0;
3747}
3748
3749static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3750{
3751        if (diff_unmodified_pair(p))
3752                return;
3753
3754        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3755            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3756                return; /* no tree diffs in patch format */
3757
3758        run_diff(p, o);
3759}
3760
3761static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3762                            struct diffstat_t *diffstat)
3763{
3764        if (diff_unmodified_pair(p))
3765                return;
3766
3767        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3768            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3769                return; /* no useful stat for tree diffs */
3770
3771        run_diffstat(p, o, diffstat);
3772}
3773
3774static void diff_flush_checkdiff(struct diff_filepair *p,
3775                struct diff_options *o)
3776{
3777        if (diff_unmodified_pair(p))
3778                return;
3779
3780        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3781            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3782                return; /* nothing to check in tree diffs */
3783
3784        run_checkdiff(p, o);
3785}
3786
3787int diff_queue_is_empty(void)
3788{
3789        struct diff_queue_struct *q = &diff_queued_diff;
3790        int i;
3791        for (i = 0; i < q->nr; i++)
3792                if (!diff_unmodified_pair(q->queue[i]))
3793                        return 0;
3794        return 1;
3795}
3796
3797#if DIFF_DEBUG
3798void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
3799{
3800        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
3801                x, one ? one : "",
3802                s->path,
3803                DIFF_FILE_VALID(s) ? "valid" : "invalid",
3804                s->mode,
3805                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
3806        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
3807                x, one ? one : "",
3808                s->size, s->xfrm_flags);
3809}
3810
3811void diff_debug_filepair(const struct diff_filepair *p, int i)
3812{
3813        diff_debug_filespec(p->one, i, "one");
3814        diff_debug_filespec(p->two, i, "two");
3815        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
3816                p->score, p->status ? p->status : '?',
3817                p->one->rename_used, p->broken_pair);
3818}
3819
3820void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
3821{
3822        int i;
3823        if (msg)
3824                fprintf(stderr, "%s\n", msg);
3825        fprintf(stderr, "q->nr = %d\n", q->nr);
3826        for (i = 0; i < q->nr; i++) {
3827                struct diff_filepair *p = q->queue[i];
3828                diff_debug_filepair(p, i);
3829        }
3830}
3831#endif
3832
3833static void diff_resolve_rename_copy(void)
3834{
3835        int i;
3836        struct diff_filepair *p;
3837        struct diff_queue_struct *q = &diff_queued_diff;
3838
3839        diff_debug_queue("resolve-rename-copy", q);
3840
3841        for (i = 0; i < q->nr; i++) {
3842                p = q->queue[i];
3843                p->status = 0; /* undecided */
3844                if (DIFF_PAIR_UNMERGED(p))
3845                        p->status = DIFF_STATUS_UNMERGED;
3846                else if (!DIFF_FILE_VALID(p->one))
3847                        p->status = DIFF_STATUS_ADDED;
3848                else if (!DIFF_FILE_VALID(p->two))
3849                        p->status = DIFF_STATUS_DELETED;
3850                else if (DIFF_PAIR_TYPE_CHANGED(p))
3851                        p->status = DIFF_STATUS_TYPE_CHANGED;
3852
3853                /* from this point on, we are dealing with a pair
3854                 * whose both sides are valid and of the same type, i.e.
3855                 * either in-place edit or rename/copy edit.
3856                 */
3857                else if (DIFF_PAIR_RENAME(p)) {
3858                        /*
3859                         * A rename might have re-connected a broken
3860                         * pair up, causing the pathnames to be the
3861                         * same again. If so, that's not a rename at
3862                         * all, just a modification..
3863                         *
3864                         * Otherwise, see if this source was used for
3865                         * multiple renames, in which case we decrement
3866                         * the count, and call it a copy.
3867                         */
3868                        if (!strcmp(p->one->path, p->two->path))
3869                                p->status = DIFF_STATUS_MODIFIED;
3870                        else if (--p->one->rename_used > 0)
3871                                p->status = DIFF_STATUS_COPIED;
3872                        else
3873                                p->status = DIFF_STATUS_RENAMED;
3874                }
3875                else if (hashcmp(p->one->sha1, p->two->sha1) ||
3876                         p->one->mode != p->two->mode ||
3877                         p->one->dirty_submodule ||
3878                         p->two->dirty_submodule ||
3879                         is_null_sha1(p->one->sha1))
3880                        p->status = DIFF_STATUS_MODIFIED;
3881                else {
3882                        /* This is a "no-change" entry and should not
3883                         * happen anymore, but prepare for broken callers.
3884                         */
3885                        error("feeding unmodified %s to diffcore",
3886                              p->one->path);
3887                        p->status = DIFF_STATUS_UNKNOWN;
3888                }
3889        }
3890        diff_debug_queue("resolve-rename-copy done", q);
3891}
3892
3893static int check_pair_status(struct diff_filepair *p)
3894{
3895        switch (p->status) {
3896        case DIFF_STATUS_UNKNOWN:
3897                return 0;
3898        case 0:
3899                die("internal error in diff-resolve-rename-copy");
3900        default:
3901                return 1;
3902        }
3903}
3904
3905static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
3906{
3907        int fmt = opt->output_format;
3908
3909        if (fmt & DIFF_FORMAT_CHECKDIFF)
3910                diff_flush_checkdiff(p, opt);
3911        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
3912                diff_flush_raw(p, opt);
3913        else if (fmt & DIFF_FORMAT_NAME) {
3914                const char *name_a, *name_b;
3915                name_a = p->two->path;
3916                name_b = NULL;
3917                strip_prefix(opt->prefix_length, &name_a, &name_b);
3918                write_name_quoted(name_a, opt->file, opt->line_termination);
3919        }
3920}
3921
3922static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
3923{
3924        if (fs->mode)
3925                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
3926        else
3927                fprintf(file, " %s ", newdelete);
3928        write_name_quoted(fs->path, file, '\n');
3929}
3930
3931
3932static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
3933                const char *line_prefix)
3934{
3935        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
3936                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
3937                        p->two->mode, show_name ? ' ' : '\n');
3938                if (show_name) {
3939                        write_name_quoted(p->two->path, file, '\n');
3940                }
3941        }
3942}
3943
3944static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
3945                        const char *line_prefix)
3946{
3947        char *names = pprint_rename(p->one->path, p->two->path);
3948
3949        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
3950        free(names);
3951        show_mode_change(file, p, 0, line_prefix);
3952}
3953
3954static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
3955{
3956        FILE *file = opt->file;
3957        char *line_prefix = "";
3958
3959        if (opt->output_prefix) {
3960                struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
3961                line_prefix = buf->buf;
3962        }
3963
3964        switch(p->status) {
3965        case DIFF_STATUS_DELETED:
3966                fputs(line_prefix, file);
3967                show_file_mode_name(file, "delete", p->one);
3968                break;
3969        case DIFF_STATUS_ADDED:
3970                fputs(line_prefix, file);
3971                show_file_mode_name(file, "create", p->two);
3972                break;
3973        case DIFF_STATUS_COPIED:
3974                fputs(line_prefix, file);
3975                show_rename_copy(file, "copy", p, line_prefix);
3976                break;
3977        case DIFF_STATUS_RENAMED:
3978                fputs(line_prefix, file);
3979                show_rename_copy(file, "rename", p, line_prefix);
3980                break;
3981        default:
3982                if (p->score) {
3983                        fprintf(file, "%s rewrite ", line_prefix);
3984                        write_name_quoted(p->two->path, file, ' ');
3985                        fprintf(file, "(%d%%)\n", similarity_index(p));
3986                }
3987                show_mode_change(file, p, !p->score, line_prefix);
3988                break;
3989        }
3990}
3991
3992struct patch_id_t {
3993        git_SHA_CTX *ctx;
3994        int patchlen;
3995};
3996
3997static int remove_space(char *line, int len)
3998{
3999        int i;
4000        char *dst = line;
4001        unsigned char c;
4002
4003        for (i = 0; i < len; i++)
4004                if (!isspace((c = line[i])))
4005                        *dst++ = c;
4006
4007        return dst - line;
4008}
4009
4010static void patch_id_consume(void *priv, char *line, unsigned long len)
4011{
4012        struct patch_id_t *data = priv;
4013        int new_len;
4014
4015        /* Ignore line numbers when computing the SHA1 of the patch */
4016        if (!prefixcmp(line, "@@ -"))
4017                return;
4018
4019        new_len = remove_space(line, len);
4020
4021        git_SHA1_Update(data->ctx, line, new_len);
4022        data->patchlen += new_len;
4023}
4024
4025/* returns 0 upon success, and writes result into sha1 */
4026static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4027{
4028        struct diff_queue_struct *q = &diff_queued_diff;
4029        int i;
4030        git_SHA_CTX ctx;
4031        struct patch_id_t data;
4032        char buffer[PATH_MAX * 4 + 20];
4033
4034        git_SHA1_Init(&ctx);
4035        memset(&data, 0, sizeof(struct patch_id_t));
4036        data.ctx = &ctx;
4037
4038        for (i = 0; i < q->nr; i++) {
4039                xpparam_t xpp;
4040                xdemitconf_t xecfg;
4041                mmfile_t mf1, mf2;
4042                struct diff_filepair *p = q->queue[i];
4043                int len1, len2;
4044
4045                memset(&xpp, 0, sizeof(xpp));
4046                memset(&xecfg, 0, sizeof(xecfg));
4047                if (p->status == 0)
4048                        return error("internal diff status error");
4049                if (p->status == DIFF_STATUS_UNKNOWN)
4050                        continue;
4051                if (diff_unmodified_pair(p))
4052                        continue;
4053                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4054                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4055                        continue;
4056                if (DIFF_PAIR_UNMERGED(p))
4057                        continue;
4058
4059                diff_fill_sha1_info(p->one);
4060                diff_fill_sha1_info(p->two);
4061                if (fill_mmfile(&mf1, p->one) < 0 ||
4062                                fill_mmfile(&mf2, p->two) < 0)
4063                        return error("unable to read files to diff");
4064
4065                len1 = remove_space(p->one->path, strlen(p->one->path));
4066                len2 = remove_space(p->two->path, strlen(p->two->path));
4067                if (p->one->mode == 0)
4068                        len1 = snprintf(buffer, sizeof(buffer),
4069                                        "diff--gita/%.*sb/%.*s"
4070                                        "newfilemode%06o"
4071                                        "---/dev/null"
4072                                        "+++b/%.*s",
4073                                        len1, p->one->path,
4074                                        len2, p->two->path,
4075                                        p->two->mode,
4076                                        len2, p->two->path);
4077                else if (p->two->mode == 0)
4078                        len1 = snprintf(buffer, sizeof(buffer),
4079                                        "diff--gita/%.*sb/%.*s"
4080                                        "deletedfilemode%06o"
4081                                        "---a/%.*s"
4082                                        "+++/dev/null",
4083                                        len1, p->one->path,
4084                                        len2, p->two->path,
4085                                        p->one->mode,
4086                                        len1, p->one->path);
4087                else
4088                        len1 = snprintf(buffer, sizeof(buffer),
4089                                        "diff--gita/%.*sb/%.*s"
4090                                        "---a/%.*s"
4091                                        "+++b/%.*s",
4092                                        len1, p->one->path,
4093                                        len2, p->two->path,
4094                                        len1, p->one->path,
4095                                        len2, p->two->path);
4096                git_SHA1_Update(&ctx, buffer, len1);
4097
4098                if (diff_filespec_is_binary(p->one) ||
4099                    diff_filespec_is_binary(p->two)) {
4100                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4101                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4102                        continue;
4103                }
4104
4105                xpp.flags = 0;
4106                xecfg.ctxlen = 3;
4107                xecfg.flags = 0;
4108                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4109                              &xpp, &xecfg);
4110        }
4111
4112        git_SHA1_Final(sha1, &ctx);
4113        return 0;
4114}
4115
4116int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4117{
4118        struct diff_queue_struct *q = &diff_queued_diff;
4119        int i;
4120        int result = diff_get_patch_id(options, sha1);
4121
4122        for (i = 0; i < q->nr; i++)
4123                diff_free_filepair(q->queue[i]);
4124
4125        free(q->queue);
4126        DIFF_QUEUE_CLEAR(q);
4127
4128        return result;
4129}
4130
4131static int is_summary_empty(const struct diff_queue_struct *q)
4132{
4133        int i;
4134
4135        for (i = 0; i < q->nr; i++) {
4136                const struct diff_filepair *p = q->queue[i];
4137
4138                switch (p->status) {
4139                case DIFF_STATUS_DELETED:
4140                case DIFF_STATUS_ADDED:
4141                case DIFF_STATUS_COPIED:
4142                case DIFF_STATUS_RENAMED:
4143                        return 0;
4144                default:
4145                        if (p->score)
4146                                return 0;
4147                        if (p->one->mode && p->two->mode &&
4148                            p->one->mode != p->two->mode)
4149                                return 0;
4150                        break;
4151                }
4152        }
4153        return 1;
4154}
4155
4156static const char rename_limit_warning[] =
4157"inexact rename detection was skipped due to too many files.";
4158
4159static const char degrade_cc_to_c_warning[] =
4160"only found copies from modified paths due to too many files.";
4161
4162static const char rename_limit_advice[] =
4163"you may want to set your %s variable to at least "
4164"%d and retry the command.";
4165
4166void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4167{
4168        if (degraded_cc)
4169                warning(degrade_cc_to_c_warning);
4170        else if (needed)
4171                warning(rename_limit_warning);
4172        else
4173                return;
4174        if (0 < needed && needed < 32767)
4175                warning(rename_limit_advice, varname, needed);
4176}
4177
4178void diff_flush(struct diff_options *options)
4179{
4180        struct diff_queue_struct *q = &diff_queued_diff;
4181        int i, output_format = options->output_format;
4182        int separator = 0;
4183        int dirstat_by_line = 0;
4184
4185        /*
4186         * Order: raw, stat, summary, patch
4187         * or:    name/name-status/checkdiff (other bits clear)
4188         */
4189        if (!q->nr)
4190                goto free_queue;
4191
4192        if (output_format & (DIFF_FORMAT_RAW |
4193                             DIFF_FORMAT_NAME |
4194                             DIFF_FORMAT_NAME_STATUS |
4195                             DIFF_FORMAT_CHECKDIFF)) {
4196                for (i = 0; i < q->nr; i++) {
4197                        struct diff_filepair *p = q->queue[i];
4198                        if (check_pair_status(p))
4199                                flush_one_pair(p, options);
4200                }
4201                separator++;
4202        }
4203
4204        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4205                dirstat_by_line = 1;
4206
4207        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4208            dirstat_by_line) {
4209                struct diffstat_t diffstat;
4210
4211                memset(&diffstat, 0, sizeof(struct diffstat_t));
4212                for (i = 0; i < q->nr; i++) {
4213                        struct diff_filepair *p = q->queue[i];
4214                        if (check_pair_status(p))
4215                                diff_flush_stat(p, options, &diffstat);
4216                }
4217                if (output_format & DIFF_FORMAT_NUMSTAT)
4218                        show_numstat(&diffstat, options);
4219                if (output_format & DIFF_FORMAT_DIFFSTAT)
4220                        show_stats(&diffstat, options);
4221                if (output_format & DIFF_FORMAT_SHORTSTAT)
4222                        show_shortstats(&diffstat, options);
4223                if (output_format & DIFF_FORMAT_DIRSTAT)
4224                        show_dirstat_by_line(&diffstat, options);
4225                free_diffstat_info(&diffstat);
4226                separator++;
4227        }
4228        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4229                show_dirstat(options);
4230
4231        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4232                for (i = 0; i < q->nr; i++) {
4233                        diff_summary(options, q->queue[i]);
4234                }
4235                separator++;
4236        }
4237
4238        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4239            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4240            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4241                /*
4242                 * run diff_flush_patch for the exit status. setting
4243                 * options->file to /dev/null should be safe, becaue we
4244                 * aren't supposed to produce any output anyway.
4245                 */
4246                if (options->close_file)
4247                        fclose(options->file);
4248                options->file = fopen("/dev/null", "w");
4249                if (!options->file)
4250                        die_errno("Could not open /dev/null");
4251                options->close_file = 1;
4252                for (i = 0; i < q->nr; i++) {
4253                        struct diff_filepair *p = q->queue[i];
4254                        if (check_pair_status(p))
4255                                diff_flush_patch(p, options);
4256                        if (options->found_changes)
4257                                break;
4258                }
4259        }
4260
4261        if (output_format & DIFF_FORMAT_PATCH) {
4262                if (separator) {
4263                        putc(options->line_termination, options->file);
4264                        if (options->stat_sep) {
4265                                /* attach patch instead of inline */
4266                                fputs(options->stat_sep, options->file);
4267                        }
4268                }
4269
4270                for (i = 0; i < q->nr; i++) {
4271                        struct diff_filepair *p = q->queue[i];
4272                        if (check_pair_status(p))
4273                                diff_flush_patch(p, options);
4274                }
4275        }
4276
4277        if (output_format & DIFF_FORMAT_CALLBACK)
4278                options->format_callback(q, options, options->format_callback_data);
4279
4280        for (i = 0; i < q->nr; i++)
4281                diff_free_filepair(q->queue[i]);
4282free_queue:
4283        free(q->queue);
4284        DIFF_QUEUE_CLEAR(q);
4285        if (options->close_file)
4286                fclose(options->file);
4287
4288        /*
4289         * Report the content-level differences with HAS_CHANGES;
4290         * diff_addremove/diff_change does not set the bit when
4291         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4292         */
4293        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4294                if (options->found_changes)
4295                        DIFF_OPT_SET(options, HAS_CHANGES);
4296                else
4297                        DIFF_OPT_CLR(options, HAS_CHANGES);
4298        }
4299}
4300
4301static void diffcore_apply_filter(const char *filter)
4302{
4303        int i;
4304        struct diff_queue_struct *q = &diff_queued_diff;
4305        struct diff_queue_struct outq;
4306        DIFF_QUEUE_CLEAR(&outq);
4307
4308        if (!filter)
4309                return;
4310
4311        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4312                int found;
4313                for (i = found = 0; !found && i < q->nr; i++) {
4314                        struct diff_filepair *p = q->queue[i];
4315                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4316                             ((p->score &&
4317                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4318                              (!p->score &&
4319                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4320                            ((p->status != DIFF_STATUS_MODIFIED) &&
4321                             strchr(filter, p->status)))
4322                                found++;
4323                }
4324                if (found)
4325                        return;
4326
4327                /* otherwise we will clear the whole queue
4328                 * by copying the empty outq at the end of this
4329                 * function, but first clear the current entries
4330                 * in the queue.
4331                 */
4332                for (i = 0; i < q->nr; i++)
4333                        diff_free_filepair(q->queue[i]);
4334        }
4335        else {
4336                /* Only the matching ones */
4337                for (i = 0; i < q->nr; i++) {
4338                        struct diff_filepair *p = q->queue[i];
4339
4340                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4341                             ((p->score &&
4342                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4343                              (!p->score &&
4344                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4345                            ((p->status != DIFF_STATUS_MODIFIED) &&
4346                             strchr(filter, p->status)))
4347                                diff_q(&outq, p);
4348                        else
4349                                diff_free_filepair(p);
4350                }
4351        }
4352        free(q->queue);
4353        *q = outq;
4354}
4355
4356/* Check whether two filespecs with the same mode and size are identical */
4357static int diff_filespec_is_identical(struct diff_filespec *one,
4358                                      struct diff_filespec *two)
4359{
4360        if (S_ISGITLINK(one->mode))
4361                return 0;
4362        if (diff_populate_filespec(one, 0))
4363                return 0;
4364        if (diff_populate_filespec(two, 0))
4365                return 0;
4366        return !memcmp(one->data, two->data, one->size);
4367}
4368
4369static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4370{
4371        int i;
4372        struct diff_queue_struct *q = &diff_queued_diff;
4373        struct diff_queue_struct outq;
4374        DIFF_QUEUE_CLEAR(&outq);
4375
4376        for (i = 0; i < q->nr; i++) {
4377                struct diff_filepair *p = q->queue[i];
4378
4379                /*
4380                 * 1. Entries that come from stat info dirtiness
4381                 *    always have both sides (iow, not create/delete),
4382                 *    one side of the object name is unknown, with
4383                 *    the same mode and size.  Keep the ones that
4384                 *    do not match these criteria.  They have real
4385                 *    differences.
4386                 *
4387                 * 2. At this point, the file is known to be modified,
4388                 *    with the same mode and size, and the object
4389                 *    name of one side is unknown.  Need to inspect
4390                 *    the identical contents.
4391                 */
4392                if (!DIFF_FILE_VALID(p->one) || /* (1) */
4393                    !DIFF_FILE_VALID(p->two) ||
4394                    (p->one->sha1_valid && p->two->sha1_valid) ||
4395                    (p->one->mode != p->two->mode) ||
4396                    diff_populate_filespec(p->one, 1) ||
4397                    diff_populate_filespec(p->two, 1) ||
4398                    (p->one->size != p->two->size) ||
4399                    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4400                        diff_q(&outq, p);
4401                else {
4402                        /*
4403                         * The caller can subtract 1 from skip_stat_unmatch
4404                         * to determine how many paths were dirty only
4405                         * due to stat info mismatch.
4406                         */
4407                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4408                                diffopt->skip_stat_unmatch++;
4409                        diff_free_filepair(p);
4410                }
4411        }
4412        free(q->queue);
4413        *q = outq;
4414}
4415
4416static int diffnamecmp(const void *a_, const void *b_)
4417{
4418        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4419        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4420        const char *name_a, *name_b;
4421
4422        name_a = a->one ? a->one->path : a->two->path;
4423        name_b = b->one ? b->one->path : b->two->path;
4424        return strcmp(name_a, name_b);
4425}
4426
4427void diffcore_fix_diff_index(struct diff_options *options)
4428{
4429        struct diff_queue_struct *q = &diff_queued_diff;
4430        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4431}
4432
4433void diffcore_std(struct diff_options *options)
4434{
4435        if (options->skip_stat_unmatch)
4436                diffcore_skip_stat_unmatch(options);
4437        if (!options->found_follow) {
4438                /* See try_to_follow_renames() in tree-diff.c */
4439                if (options->break_opt != -1)
4440                        diffcore_break(options->break_opt);
4441                if (options->detect_rename)
4442                        diffcore_rename(options);
4443                if (options->break_opt != -1)
4444                        diffcore_merge_broken();
4445        }
4446        if (options->pickaxe)
4447                diffcore_pickaxe(options);
4448        if (options->orderfile)
4449                diffcore_order(options->orderfile);
4450        if (!options->found_follow)
4451                /* See try_to_follow_renames() in tree-diff.c */
4452                diff_resolve_rename_copy();
4453        diffcore_apply_filter(options->filter);
4454
4455        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4456                DIFF_OPT_SET(options, HAS_CHANGES);
4457        else
4458                DIFF_OPT_CLR(options, HAS_CHANGES);
4459
4460        options->found_follow = 0;
4461}
4462
4463int diff_result_code(struct diff_options *opt, int status)
4464{
4465        int result = 0;
4466
4467        diff_warn_rename_limit("diff.renamelimit",
4468                               opt->needed_rename_limit,
4469                               opt->degraded_cc_to_c);
4470        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4471            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4472                return status;
4473        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4474            DIFF_OPT_TST(opt, HAS_CHANGES))
4475                result |= 01;
4476        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4477            DIFF_OPT_TST(opt, CHECK_FAILED))
4478                result |= 02;
4479        return result;
4480}
4481
4482int diff_can_quit_early(struct diff_options *opt)
4483{
4484        return (DIFF_OPT_TST(opt, QUICK) &&
4485                !opt->filter &&
4486                DIFF_OPT_TST(opt, HAS_CHANGES));
4487}
4488
4489/*
4490 * Shall changes to this submodule be ignored?
4491 *
4492 * Submodule changes can be configured to be ignored separately for each path,
4493 * but that configuration can be overridden from the command line.
4494 */
4495static int is_submodule_ignored(const char *path, struct diff_options *options)
4496{
4497        int ignored = 0;
4498        unsigned orig_flags = options->flags;
4499        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4500                set_diffopt_flags_from_submodule_config(options, path);
4501        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4502                ignored = 1;
4503        options->flags = orig_flags;
4504        return ignored;
4505}
4506
4507void diff_addremove(struct diff_options *options,
4508                    int addremove, unsigned mode,
4509                    const unsigned char *sha1,
4510                    const char *concatpath, unsigned dirty_submodule)
4511{
4512        struct diff_filespec *one, *two;
4513
4514        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4515                return;
4516
4517        /* This may look odd, but it is a preparation for
4518         * feeding "there are unchanged files which should
4519         * not produce diffs, but when you are doing copy
4520         * detection you would need them, so here they are"
4521         * entries to the diff-core.  They will be prefixed
4522         * with something like '=' or '*' (I haven't decided
4523         * which but should not make any difference).
4524         * Feeding the same new and old to diff_change()
4525         * also has the same effect.
4526         * Before the final output happens, they are pruned after
4527         * merged into rename/copy pairs as appropriate.
4528         */
4529        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4530                addremove = (addremove == '+' ? '-' :
4531                             addremove == '-' ? '+' : addremove);
4532
4533        if (options->prefix &&
4534            strncmp(concatpath, options->prefix, options->prefix_length))
4535                return;
4536
4537        one = alloc_filespec(concatpath);
4538        two = alloc_filespec(concatpath);
4539
4540        if (addremove != '+')
4541                fill_filespec(one, sha1, mode);
4542        if (addremove != '-') {
4543                fill_filespec(two, sha1, mode);
4544                two->dirty_submodule = dirty_submodule;
4545        }
4546
4547        diff_queue(&diff_queued_diff, one, two);
4548        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4549                DIFF_OPT_SET(options, HAS_CHANGES);
4550}
4551
4552void diff_change(struct diff_options *options,
4553                 unsigned old_mode, unsigned new_mode,
4554                 const unsigned char *old_sha1,
4555                 const unsigned char *new_sha1,
4556                 const char *concatpath,
4557                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4558{
4559        struct diff_filespec *one, *two;
4560
4561        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4562            is_submodule_ignored(concatpath, options))
4563                return;
4564
4565        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4566                unsigned tmp;
4567                const unsigned char *tmp_c;
4568                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4569                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4570                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4571                        new_dirty_submodule = tmp;
4572        }
4573
4574        if (options->prefix &&
4575            strncmp(concatpath, options->prefix, options->prefix_length))
4576                return;
4577
4578        one = alloc_filespec(concatpath);
4579        two = alloc_filespec(concatpath);
4580        fill_filespec(one, old_sha1, old_mode);
4581        fill_filespec(two, new_sha1, new_mode);
4582        one->dirty_submodule = old_dirty_submodule;
4583        two->dirty_submodule = new_dirty_submodule;
4584
4585        diff_queue(&diff_queued_diff, one, two);
4586        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4587                DIFF_OPT_SET(options, HAS_CHANGES);
4588}
4589
4590struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4591{
4592        struct diff_filepair *pair;
4593        struct diff_filespec *one, *two;
4594
4595        if (options->prefix &&
4596            strncmp(path, options->prefix, options->prefix_length))
4597                return NULL;
4598
4599        one = alloc_filespec(path);
4600        two = alloc_filespec(path);
4601        pair = diff_queue(&diff_queued_diff, one, two);
4602        pair->is_unmerged = 1;
4603        return pair;
4604}
4605
4606static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4607                size_t *outsize)
4608{
4609        struct diff_tempfile *temp;
4610        const char *argv[3];
4611        const char **arg = argv;
4612        struct child_process child;
4613        struct strbuf buf = STRBUF_INIT;
4614        int err = 0;
4615
4616        temp = prepare_temp_file(spec->path, spec);
4617        *arg++ = pgm;
4618        *arg++ = temp->name;
4619        *arg = NULL;
4620
4621        memset(&child, 0, sizeof(child));
4622        child.use_shell = 1;
4623        child.argv = argv;
4624        child.out = -1;
4625        if (start_command(&child)) {
4626                remove_tempfile();
4627                return NULL;
4628        }
4629
4630        if (strbuf_read(&buf, child.out, 0) < 0)
4631                err = error("error reading from textconv command '%s'", pgm);
4632        close(child.out);
4633
4634        if (finish_command(&child) || err) {
4635                strbuf_release(&buf);
4636                remove_tempfile();
4637                return NULL;
4638        }
4639        remove_tempfile();
4640
4641        return strbuf_detach(&buf, outsize);
4642}
4643
4644size_t fill_textconv(struct userdiff_driver *driver,
4645                     struct diff_filespec *df,
4646                     char **outbuf)
4647{
4648        size_t size;
4649
4650        if (!driver || !driver->textconv) {
4651                if (!DIFF_FILE_VALID(df)) {
4652                        *outbuf = "";
4653                        return 0;
4654                }
4655                if (diff_populate_filespec(df, 0))
4656                        die("unable to read files to diff");
4657                *outbuf = df->data;
4658                return df->size;
4659        }
4660
4661        if (driver->textconv_cache && df->sha1_valid) {
4662                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4663                                          &size);
4664                if (*outbuf)
4665                        return size;
4666        }
4667
4668        *outbuf = run_textconv(driver->textconv, df, &size);
4669        if (!*outbuf)
4670                die("unable to read files to diff");
4671
4672        if (driver->textconv_cache && df->sha1_valid) {
4673                /* ignore errors, as we might be in a readonly repository */
4674                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4675                                size);
4676                /*
4677                 * we could save up changes and flush them all at the end,
4678                 * but we would need an extra call after all diffing is done.
4679                 * Since generating a cache entry is the slow path anyway,
4680                 * this extra overhead probably isn't a big deal.
4681                 */
4682                notes_cache_write(driver->textconv_cache);
4683        }
4684
4685        return size;
4686}