strbuf.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "utf8.h"
   4
   5 int starts_with(const char *str, const char *prefix)
   6 {
   7         for (; ; str++, prefix++)
   8                 if (!*prefix)
   9                         return 1;
  10                 else if (*str != *prefix)
  11                         return 0;
  12 }
  13
  14 int skip_to_optional_arg_default(const char *str, const char *prefix,
  15                                  const char **arg, const char *def)
  16 {
  17         const char *p;
  18
  19         if (!skip_prefix(str, prefix, &p))
  20                 return 0;
  21
  22         if (!*p) {
  23                 if (arg)
  24                         *arg = def;
  25                 return 1;
  26         }
  27
  28         if (*p != '=')
  29                 return 0;
  30
  31         if (arg)
  32                 *arg = p + 1;
  33         return 1;
  34 }
  35
  36 /*
  37  * Used as the default ->buf value, so that people can always assume
  38  * buf is non NULL and ->buf is NUL terminated even for a freshly
  39  * initialized strbuf.
  40  */
  41 char strbuf_slopbuf[1];
  42
  43 void strbuf_init(struct strbuf *sb, size_t hint)
  44 {
  45         sb->alloc = sb->len = 0;
  46         sb->buf = strbuf_slopbuf;
  47         if (hint)
  48                 strbuf_grow(sb, hint);
  49 }
  50
  51 void strbuf_release(struct strbuf *sb)
  52 {
  53         if (sb->alloc) {
  54                 free(sb->buf);
  55                 strbuf_init(sb, 0);
  56         }
  57 }
  58
  59 char *strbuf_detach(struct strbuf *sb, size_t *sz)
  60 {
  61         char *res;
  62         strbuf_grow(sb, 0);
  63         res = sb->buf;
  64         if (sz)
  65                 *sz = sb->len;
  66         strbuf_init(sb, 0);
  67         return res;
  68 }
  69
  70 void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc)
  71 {
  72         strbuf_release(sb);
  73         sb->buf   = buf;
  74         sb->len   = len;
  75         sb->alloc = alloc;
  76         strbuf_grow(sb, 0);
  77         sb->buf[sb->len] = '\0';
  78 }
  79
  80 void strbuf_grow(struct strbuf *sb, size_t extra)
  81 {
  82         int new_buf = !sb->alloc;
  83         if (unsigned_add_overflows(extra, 1) ||
  84             unsigned_add_overflows(sb->len, extra + 1))
  85                 die("you want to use way too much memory");
  86         if (new_buf)
  87                 sb->buf = NULL;
  88         ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
  89         if (new_buf)
  90                 sb->buf[0] = '\0';
  91 }
  92
  93 void strbuf_trim(struct strbuf *sb)
  94 {
  95         strbuf_rtrim(sb);
  96         strbuf_ltrim(sb);
  97 }
  98
  99 void strbuf_rtrim(struct strbuf *sb)
 100 {
 101         while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
 102                 sb->len--;
 103         sb->buf[sb->len] = '\0';
 104 }
 105
 106 void strbuf_trim_trailing_dir_sep(struct strbuf *sb)
 107 {
 108         while (sb->len > 0 && is_dir_sep((unsigned char)sb->buf[sb->len - 1]))
 109                 sb->len--;
 110         sb->buf[sb->len] = '\0';
 111 }
 112
 113 void strbuf_ltrim(struct strbuf *sb)
 114 {
 115         char *b = sb->buf;
 116         while (sb->len > 0 && isspace(*b)) {
 117                 b++;
 118                 sb->len--;
 119         }
 120         memmove(sb->buf, b, sb->len);
 121         sb->buf[sb->len] = '\0';
 122 }
 123
 124 int strbuf_reencode(struct strbuf *sb, const char *from, const char *to)
 125 {
 126         char *out;
 127         int len;
 128
 129         if (same_encoding(from, to))
 130                 return 0;
 131
 132         out = reencode_string_len(sb->buf, sb->len, to, from, &len);
 133         if (!out)
 134                 return -1;
 135
 136         strbuf_attach(sb, out, len, len);
 137         return 0;
 138 }
 139
 140 void strbuf_tolower(struct strbuf *sb)
 141 {
 142         char *p = sb->buf, *end = sb->buf + sb->len;
 143         for (; p < end; p++)
 144                 *p = tolower(*p);
 145 }
 146
 147 struct strbuf **strbuf_split_buf(const char *str, size_t slen,
 148                                  int terminator, int max)
 149 {
 150         struct strbuf **ret = NULL;
 151         size_t nr = 0, alloc = 0;
 152         struct strbuf *t;
 153
 154         while (slen) {
 155                 int len = slen;
 156                 if (max <= 0 || nr + 1 < max) {
 157                         const char *end = memchr(str, terminator, slen);
 158                         if (end)
 159                                 len = end - str + 1;
 160                 }
 161                 t = xmalloc(sizeof(struct strbuf));
 162                 strbuf_init(t, len);
 163                 strbuf_add(t, str, len);
 164                 ALLOC_GROW(ret, nr + 2, alloc);
 165                 ret[nr++] = t;
 166                 str += len;
 167                 slen -= len;
 168         }
 169         ALLOC_GROW(ret, nr + 1, alloc); /* In case string was empty */
 170         ret[nr] = NULL;
 171         return ret;
 172 }
 173
 174 void strbuf_list_free(struct strbuf **sbs)
 175 {
 176         struct strbuf **s = sbs;
 177
 178         while (*s) {
 179                 strbuf_release(*s);
 180                 free(*s++);
 181         }
 182         free(sbs);
 183 }
 184
 185 int strbuf_cmp(const struct strbuf *a, const struct strbuf *b)
 186 {
 187         int len = a->len < b->len ? a->len: b->len;
 188         int cmp = memcmp(a->buf, b->buf, len);
 189         if (cmp)
 190                 return cmp;
 191         return a->len < b->len ? -1: a->len != b->len;
 192 }
 193
 194 void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
 195                                    const void *data, size_t dlen)
 196 {
 197         if (unsigned_add_overflows(pos, len))
 198                 die("you want to use way too much memory");
 199         if (pos > sb->len)
 200                 die("`pos' is too far after the end of the buffer");
 201         if (pos + len > sb->len)
 202                 die("`pos + len' is too far after the end of the buffer");
 203
 204         if (dlen >= len)
 205                 strbuf_grow(sb, dlen - len);
 206         memmove(sb->buf + pos + dlen,
 207                         sb->buf + pos + len,
 208                         sb->len - pos - len);
 209         memcpy(sb->buf + pos, data, dlen);
 210         strbuf_setlen(sb, sb->len + dlen - len);
 211 }
 212
 213 void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len)
 214 {
 215         strbuf_splice(sb, pos, 0, data, len);
 216 }
 217
 218 void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
 219 {
 220         strbuf_splice(sb, pos, len, "", 0);
 221 }
 222
 223 void strbuf_add(struct strbuf *sb, const void *data, size_t len)
 224 {
 225         strbuf_grow(sb, len);
 226         memcpy(sb->buf + sb->len, data, len);
 227         strbuf_setlen(sb, sb->len + len);
 228 }
 229
 230 void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
 231 {
 232         strbuf_grow(sb, sb2->len);
 233         memcpy(sb->buf + sb->len, sb2->buf, sb2->len);
 234         strbuf_setlen(sb, sb->len + sb2->len);
 235 }
 236
 237 void strbuf_addchars(struct strbuf *sb, int c, size_t n)
 238 {
 239         strbuf_grow(sb, n);
 240         memset(sb->buf + sb->len, c, n);
 241         strbuf_setlen(sb, sb->len + n);
 242 }
 243
 244 void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
 245 {
 246         va_list ap;
 247         va_start(ap, fmt);
 248         strbuf_vaddf(sb, fmt, ap);
 249         va_end(ap);
 250 }
 251
 252 static void add_lines(struct strbuf *out,
 253                         const char *prefix1,
 254                         const char *prefix2,
 255                         const char *buf, size_t size)
 256 {
 257         while (size) {
 258                 const char *prefix;
 259                 const char *next = memchr(buf, '\n', size);
 260                 next = next ? (next + 1) : (buf + size);
 261
 262                 prefix = ((prefix2 && (buf[0] == '\n' || buf[0] == '\t'))
 263                           ? prefix2 : prefix1);
 264                 strbuf_addstr(out, prefix);
 265                 strbuf_add(out, buf, next - buf);
 266                 size -= next - buf;
 267                 buf = next;
 268         }
 269         strbuf_complete_line(out);
 270 }
 271
 272 void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size)
 273 {
 274         static char prefix1[3];
 275         static char prefix2[2];
 276
 277         if (prefix1[0] != comment_line_char) {
 278                 xsnprintf(prefix1, sizeof(prefix1), "%c ", comment_line_char);
 279                 xsnprintf(prefix2, sizeof(prefix2), "%c", comment_line_char);
 280         }
 281         add_lines(out, prefix1, prefix2, buf, size);
 282 }
 283
 284 void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...)
 285 {
 286         va_list params;
 287         struct strbuf buf = STRBUF_INIT;
 288         int incomplete_line = sb->len && sb->buf[sb->len - 1] != '\n';
 289
 290         va_start(params, fmt);
 291         strbuf_vaddf(&buf, fmt, params);
 292         va_end(params);
 293
 294         strbuf_add_commented_lines(sb, buf.buf, buf.len);
 295         if (incomplete_line)
 296                 sb->buf[--sb->len] = '\0';
 297
 298         strbuf_release(&buf);
 299 }
 300
 301 void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap)
 302 {
 303         int len;
 304         va_list cp;
 305
 306         if (!strbuf_avail(sb))
 307                 strbuf_grow(sb, 64);
 308         va_copy(cp, ap);
 309         len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, cp);
 310         va_end(cp);
 311         if (len < 0)
 312                 die("BUG: your vsnprintf is broken (returned %d)", len);
 313         if (len > strbuf_avail(sb)) {
 314                 strbuf_grow(sb, len);
 315                 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 316                 if (len > strbuf_avail(sb))
 317                         die("BUG: your vsnprintf is broken (insatiable)");
 318         }
 319         strbuf_setlen(sb, sb->len + len);
 320 }
 321
 322 void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
 323                    void *context)
 324 {
 325         for (;;) {
 326                 const char *percent;
 327                 size_t consumed;
 328
 329                 percent = strchrnul(format, '%');
 330                 strbuf_add(sb, format, percent - format);
 331                 if (!*percent)
 332                         break;
 333                 format = percent + 1;
 334
 335                 if (*format == '%') {
 336                         strbuf_addch(sb, '%');
 337                         format++;
 338                         continue;
 339                 }
 340
 341                 consumed = fn(sb, format, context);
 342                 if (consumed)
 343                         format += consumed;
 344                 else
 345                         strbuf_addch(sb, '%');
 346         }
 347 }
 348
 349 size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,
 350                 void *context)
 351 {
 352         struct strbuf_expand_dict_entry *e = context;
 353         size_t len;
 354
 355         for (; e->placeholder && (len = strlen(e->placeholder)); e++) {
 356                 if (!strncmp(placeholder, e->placeholder, len)) {
 357                         if (e->value)
 358                                 strbuf_addstr(sb, e->value);
 359                         return len;
 360                 }
 361         }
 362         return 0;
 363 }
 364
 365 void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src)
 366 {
 367         int i, len = src->len;
 368
 369         for (i = 0; i < len; i++) {
 370                 if (src->buf[i] == '%')
 371                         strbuf_addch(dst, '%');
 372                 strbuf_addch(dst, src->buf[i]);
 373         }
 374 }
 375
 376 size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
 377 {
 378         size_t res;
 379         size_t oldalloc = sb->alloc;
 380
 381         strbuf_grow(sb, size);
 382         res = fread(sb->buf + sb->len, 1, size, f);
 383         if (res > 0)
 384                 strbuf_setlen(sb, sb->len + res);
 385         else if (oldalloc == 0)
 386                 strbuf_release(sb);
 387         return res;
 388 }
 389
 390 ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
 391 {
 392         size_t oldlen = sb->len;
 393         size_t oldalloc = sb->alloc;
 394
 395         strbuf_grow(sb, hint ? hint : 8192);
 396         for (;;) {
 397                 ssize_t want = sb->alloc - sb->len - 1;
 398                 ssize_t got = read_in_full(fd, sb->buf + sb->len, want);
 399
 400                 if (got < 0) {
 401                         if (oldalloc == 0)
 402                                 strbuf_release(sb);
 403                         else
 404                                 strbuf_setlen(sb, oldlen);
 405                         return -1;
 406                 }
 407                 sb->len += got;
 408                 if (got < want)
 409                         break;
 410                 strbuf_grow(sb, 8192);
 411         }
 412
 413         sb->buf[sb->len] = '\0';
 414         return sb->len - oldlen;
 415 }
 416
 417 ssize_t strbuf_read_once(struct strbuf *sb, int fd, size_t hint)
 418 {
 419         size_t oldalloc = sb->alloc;
 420         ssize_t cnt;
 421
 422         strbuf_grow(sb, hint ? hint : 8192);
 423         cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
 424         if (cnt > 0)
 425                 strbuf_setlen(sb, sb->len + cnt);
 426         else if (oldalloc == 0)
 427                 strbuf_release(sb);
 428         return cnt;
 429 }
 430
 431 ssize_t strbuf_write(struct strbuf *sb, FILE *f)
 432 {
 433         return sb->len ? fwrite(sb->buf, 1, sb->len, f) : 0;
 434 }
 435
 436
 437 #define STRBUF_MAXLINK (2*PATH_MAX)
 438
 439 int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 440 {
 441         size_t oldalloc = sb->alloc;
 442
 443         if (hint < 32)
 444                 hint = 32;
 445
 446         while (hint < STRBUF_MAXLINK) {
 447                 int len;
 448
 449                 strbuf_grow(sb, hint);
 450                 len = readlink(path, sb->buf, hint);
 451                 if (len < 0) {
 452                         if (errno != ERANGE)
 453                                 break;
 454                 } else if (len < hint) {
 455                         strbuf_setlen(sb, len);
 456                         return 0;
 457                 }
 458
 459                 /* .. the buffer was too small - try again */
 460                 hint *= 2;
 461         }
 462         if (oldalloc == 0)
 463                 strbuf_release(sb);
 464         return -1;
 465 }
 466
 467 int strbuf_getcwd(struct strbuf *sb)
 468 {
 469         size_t oldalloc = sb->alloc;
 470         size_t guessed_len = 128;
 471
 472         for (;; guessed_len *= 2) {
 473                 strbuf_grow(sb, guessed_len);
 474                 if (getcwd(sb->buf, sb->alloc)) {
 475                         strbuf_setlen(sb, strlen(sb->buf));
 476                         return 0;
 477                 }
 478
 479                 /*
 480                  * If getcwd(3) is implemented as a syscall that falls
 481                  * back to a regular lookup using readdir(3) etc. then
 482                  * we may be able to avoid EACCES by providing enough
 483                  * space to the syscall as it's not necessarily bound
 484                  * to the same restrictions as the fallback.
 485                  */
 486                 if (errno == EACCES && guessed_len < PATH_MAX)
 487                         continue;
 488
 489                 if (errno != ERANGE)
 490                         break;
 491         }
 492         if (oldalloc == 0)
 493                 strbuf_release(sb);
 494         else
 495                 strbuf_reset(sb);
 496         return -1;
 497 }
 498
 499 #ifdef HAVE_GETDELIM
 500 int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
 501 {
 502         ssize_t r;
 503
 504         if (feof(fp))
 505                 return EOF;
 506
 507         strbuf_reset(sb);
 508
 509         /* Translate slopbuf to NULL, as we cannot call realloc on it */
 510         if (!sb->alloc)
 511                 sb->buf = NULL;
 512         errno = 0;
 513         r = getdelim(&sb->buf, &sb->alloc, term, fp);
 514
 515         if (r > 0) {
 516                 sb->len = r;
 517                 return 0;
 518         }
 519         assert(r == -1);
 520
 521         /*
 522          * Normally we would have called xrealloc, which will try to free
 523          * memory and recover. But we have no way to tell getdelim() to do so.
 524          * Worse, we cannot try to recover ENOMEM ourselves, because we have
 525          * no idea how many bytes were read by getdelim.
 526          *
 527          * Dying here is reasonable. It mirrors what xrealloc would do on
 528          * catastrophic memory failure. We skip the opportunity to free pack
 529          * memory and retry, but that's unlikely to help for a malloc small
 530          * enough to hold a single line of input, anyway.
 531          */
 532         if (errno == ENOMEM)
 533                 die("Out of memory, getdelim failed");
 534
 535         /*
 536          * Restore strbuf invariants; if getdelim left us with a NULL pointer,
 537          * we can just re-init, but otherwise we should make sure that our
 538          * length is empty, and that the result is NUL-terminated.
 539          */
 540         if (!sb->buf)
 541                 strbuf_init(sb, 0);
 542         else
 543                 strbuf_reset(sb);
 544         return EOF;
 545 }
 546 #else
 547 int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
 548 {
 549         int ch;
 550
 551         if (feof(fp))
 552                 return EOF;
 553
 554         strbuf_reset(sb);
 555         flockfile(fp);
 556         while ((ch = getc_unlocked(fp)) != EOF) {
 557                 if (!strbuf_avail(sb))
 558                         strbuf_grow(sb, 1);
 559                 sb->buf[sb->len++] = ch;
 560                 if (ch == term)
 561                         break;
 562         }
 563         funlockfile(fp);
 564         if (ch == EOF && sb->len == 0)
 565                 return EOF;
 566
 567         sb->buf[sb->len] = '\0';
 568         return 0;
 569 }
 570 #endif
 571
 572 static int strbuf_getdelim(struct strbuf *sb, FILE *fp, int term)
 573 {
 574         if (strbuf_getwholeline(sb, fp, term))
 575                 return EOF;
 576         if (sb->buf[sb->len - 1] == term)
 577                 strbuf_setlen(sb, sb->len - 1);
 578         return 0;
 579 }
 580
 581 int strbuf_getline(struct strbuf *sb, FILE *fp)
 582 {
 583         if (strbuf_getwholeline(sb, fp, '\n'))
 584                 return EOF;
 585         if (sb->buf[sb->len - 1] == '\n') {
 586                 strbuf_setlen(sb, sb->len - 1);
 587                 if (sb->len && sb->buf[sb->len - 1] == '\r')
 588                         strbuf_setlen(sb, sb->len - 1);
 589         }
 590         return 0;
 591 }
 592
 593 int strbuf_getline_lf(struct strbuf *sb, FILE *fp)
 594 {
 595         return strbuf_getdelim(sb, fp, '\n');
 596 }
 597
 598 int strbuf_getline_nul(struct strbuf *sb, FILE *fp)
 599 {
 600         return strbuf_getdelim(sb, fp, '\0');
 601 }
 602
 603 int strbuf_getwholeline_fd(struct strbuf *sb, int fd, int term)
 604 {
 605         strbuf_reset(sb);
 606
 607         while (1) {
 608                 char ch;
 609                 ssize_t len = xread(fd, &ch, 1);
 610                 if (len <= 0)
 611                         return EOF;
 612                 strbuf_addch(sb, ch);
 613                 if (ch == term)
 614                         break;
 615         }
 616         return 0;
 617 }
 618
 619 ssize_t strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
 620 {
 621         int fd;
 622         ssize_t len;
 623         int saved_errno;
 624
 625         fd = open(path, O_RDONLY);
 626         if (fd < 0)
 627                 return -1;
 628         len = strbuf_read(sb, fd, hint);
 629         saved_errno = errno;
 630         close(fd);
 631         if (len < 0) {
 632                 errno = saved_errno;
 633                 return -1;
 634         }
 635
 636         return len;
 637 }
 638
 639 void strbuf_add_lines(struct strbuf *out, const char *prefix,
 640                       const char *buf, size_t size)
 641 {
 642         add_lines(out, prefix, NULL, buf, size);
 643 }
 644
 645 void strbuf_addstr_xml_quoted(struct strbuf *buf, const char *s)
 646 {
 647         while (*s) {
 648                 size_t len = strcspn(s, "\"<>&");
 649                 strbuf_add(buf, s, len);
 650                 s += len;
 651                 switch (*s) {
 652                 case '"':
 653                         strbuf_addstr(buf, "&quot;");
 654                         break;
 655                 case '<':
 656                         strbuf_addstr(buf, "&lt;");
 657                         break;
 658                 case '>':
 659                         strbuf_addstr(buf, "&gt;");
 660                         break;
 661                 case '&':
 662                         strbuf_addstr(buf, "&amp;");
 663                         break;
 664                 case 0:
 665                         return;
 666                 }
 667                 s++;
 668         }
 669 }
 670
 671 static int is_rfc3986_reserved(char ch)
 672 {
 673         switch (ch) {
 674                 case '!': case '*': case '\'': case '(': case ')': case ';':
 675                 case ':': case '@': case '&': case '=': case '+': case '$':
 676                 case ',': case '/': case '?': case '#': case '[': case ']':
 677                         return 1;
 678         }
 679         return 0;
 680 }
 681
 682 static int is_rfc3986_unreserved(char ch)
 683 {
 684         return isalnum(ch) ||
 685                 ch == '-' || ch == '_' || ch == '.' || ch == '~';
 686 }
 687
 688 static void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
 689                                  int reserved)
 690 {
 691         strbuf_grow(sb, len);
 692         while (len--) {
 693                 char ch = *s++;
 694                 if (is_rfc3986_unreserved(ch) ||
 695                     (!reserved && is_rfc3986_reserved(ch)))
 696                         strbuf_addch(sb, ch);
 697                 else
 698                         strbuf_addf(sb, "%%%02x", (unsigned char)ch);
 699         }
 700 }
 701
 702 void strbuf_addstr_urlencode(struct strbuf *sb, const char *s,
 703                              int reserved)
 704 {
 705         strbuf_add_urlencode(sb, s, strlen(s), reserved);
 706 }
 707
 708 void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes)
 709 {
 710         if (bytes > 1 << 30) {
 711                 strbuf_addf(buf, "%u.%2.2u GiB",
 712                             (int)(bytes >> 30),
 713                             (int)(bytes & ((1 << 30) - 1)) / 10737419);
 714         } else if (bytes > 1 << 20) {
 715                 int x = bytes + 5243;  /* for rounding */
 716                 strbuf_addf(buf, "%u.%2.2u MiB",
 717                             x >> 20, ((x & ((1 << 20) - 1)) * 100) >> 20);
 718         } else if (bytes > 1 << 10) {
 719                 int x = bytes + 5;  /* for rounding */
 720                 strbuf_addf(buf, "%u.%2.2u KiB",
 721                             x >> 10, ((x & ((1 << 10) - 1)) * 100) >> 10);
 722         } else {
 723                 strbuf_addf(buf, "%u bytes", (int)bytes);
 724         }
 725 }
 726
 727 void strbuf_add_absolute_path(struct strbuf *sb, const char *path)
 728 {
 729         if (!*path)
 730                 die("The empty string is not a valid path");
 731         if (!is_absolute_path(path)) {
 732                 struct stat cwd_stat, pwd_stat;
 733                 size_t orig_len = sb->len;
 734                 char *cwd = xgetcwd();
 735                 char *pwd = getenv("PWD");
 736                 if (pwd && strcmp(pwd, cwd) &&
 737                     !stat(cwd, &cwd_stat) &&
 738                     (cwd_stat.st_dev || cwd_stat.st_ino) &&
 739                     !stat(pwd, &pwd_stat) &&
 740                     pwd_stat.st_dev == cwd_stat.st_dev &&
 741                     pwd_stat.st_ino == cwd_stat.st_ino)
 742                         strbuf_addstr(sb, pwd);
 743                 else
 744                         strbuf_addstr(sb, cwd);
 745                 if (sb->len > orig_len && !is_dir_sep(sb->buf[sb->len - 1]))
 746                         strbuf_addch(sb, '/');
 747                 free(cwd);
 748         }
 749         strbuf_addstr(sb, path);
 750 }
 751
 752 void strbuf_add_real_path(struct strbuf *sb, const char *path)
 753 {
 754         if (sb->len) {
 755                 struct strbuf resolved = STRBUF_INIT;
 756                 strbuf_realpath(&resolved, path, 1);
 757                 strbuf_addbuf(sb, &resolved);
 758                 strbuf_release(&resolved);
 759         } else
 760                 strbuf_realpath(sb, path, 1);
 761 }
 762
 763 int printf_ln(const char *fmt, ...)
 764 {
 765         int ret;
 766         va_list ap;
 767         va_start(ap, fmt);
 768         ret = vprintf(fmt, ap);
 769         va_end(ap);
 770         if (ret < 0 || putchar('\n') == EOF)
 771                 return -1;
 772         return ret + 1;
 773 }
 774
 775 int fprintf_ln(FILE *fp, const char *fmt, ...)
 776 {
 777         int ret;
 778         va_list ap;
 779         va_start(ap, fmt);
 780         ret = vfprintf(fp, fmt, ap);
 781         va_end(ap);
 782         if (ret < 0 || putc('\n', fp) == EOF)
 783                 return -1;
 784         return ret + 1;
 785 }
 786
 787 char *xstrdup_tolower(const char *string)
 788 {
 789         char *result;
 790         size_t len, i;
 791
 792         len = strlen(string);
 793         result = xmallocz(len);
 794         for (i = 0; i < len; i++)
 795                 result[i] = tolower(string[i]);
 796         result[i] = '\0';
 797         return result;
 798 }
 799
 800 char *xstrvfmt(const char *fmt, va_list ap)
 801 {
 802         struct strbuf buf = STRBUF_INIT;
 803         strbuf_vaddf(&buf, fmt, ap);
 804         return strbuf_detach(&buf, NULL);
 805 }
 806
 807 char *xstrfmt(const char *fmt, ...)
 808 {
 809         va_list ap;
 810         char *ret;
 811
 812         va_start(ap, fmt);
 813         ret = xstrvfmt(fmt, ap);
 814         va_end(ap);
 815
 816         return ret;
 817 }
 818
 819 void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm,
 820                      int tz_offset, int suppress_tz_name)
 821 {
 822         struct strbuf munged_fmt = STRBUF_INIT;
 823         size_t hint = 128;
 824         size_t len;
 825
 826         if (!*fmt)
 827                 return;
 828
 829         /*
 830          * There is no portable way to pass timezone information to
 831          * strftime, so we handle %z and %Z here.
 832          */
 833         for (;;) {
 834                 const char *percent = strchrnul(fmt, '%');
 835                 strbuf_add(&munged_fmt, fmt, percent - fmt);
 836                 if (!*percent)
 837                         break;
 838                 fmt = percent + 1;
 839                 switch (*fmt) {
 840                 case '%':
 841                         strbuf_addstr(&munged_fmt, "%%");
 842                         fmt++;
 843                         break;
 844                 case 'z':
 845                         strbuf_addf(&munged_fmt, "%+05d", tz_offset);
 846                         fmt++;
 847                         break;
 848                 case 'Z':
 849                         if (suppress_tz_name) {
 850                                 fmt++;
 851                                 break;
 852                         }
 853                         /* FALLTHROUGH */
 854                 default:
 855                         strbuf_addch(&munged_fmt, '%');
 856                 }
 857         }
 858         fmt = munged_fmt.buf;
 859
 860         strbuf_grow(sb, hint);
 861         len = strftime(sb->buf + sb->len, sb->alloc - sb->len, fmt, tm);
 862
 863         if (!len) {
 864                 /*
 865                  * strftime reports "0" if it could not fit the result in the buffer.
 866                  * Unfortunately, it also reports "0" if the requested time string
 867                  * takes 0 bytes. So our strategy is to munge the format so that the
 868                  * output contains at least one character, and then drop the extra
 869                  * character before returning.
 870                  */
 871                 strbuf_addch(&munged_fmt, ' ');
 872                 while (!len) {
 873                         hint *= 2;
 874                         strbuf_grow(sb, hint);
 875                         len = strftime(sb->buf + sb->len, sb->alloc - sb->len,
 876                                        munged_fmt.buf, tm);
 877                 }
 878                 len--; /* drop munged space */
 879         }
 880         strbuf_release(&munged_fmt);
 881         strbuf_setlen(sb, sb->len + len);
 882 }
 883
 884 void strbuf_add_unique_abbrev(struct strbuf *sb, const struct object_id *oid,
 885                               int abbrev_len)
 886 {
 887         int r;
 888         strbuf_grow(sb, GIT_SHA1_HEXSZ + 1);
 889         r = find_unique_abbrev_r(sb->buf + sb->len, oid, abbrev_len);
 890         strbuf_setlen(sb, sb->len + r);
 891 }
 892
 893 /*
 894  * Returns the length of a line, without trailing spaces.
 895  *
 896  * If the line ends with newline, it will be removed too.
 897  */
 898 static size_t cleanup(char *line, size_t len)
 899 {
 900         while (len) {
 901                 unsigned char c = line[len - 1];
 902                 if (!isspace(c))
 903                         break;
 904                 len--;
 905         }
 906
 907         return len;
 908 }
 909
 910 /*
 911  * Remove empty lines from the beginning and end
 912  * and also trailing spaces from every line.
 913  *
 914  * Turn multiple consecutive empty lines between paragraphs
 915  * into just one empty line.
 916  *
 917  * If the input has only empty lines and spaces,
 918  * no output will be produced.
 919  *
 920  * If last line does not have a newline at the end, one is added.
 921  *
 922  * Enable skip_comments to skip every line starting with comment
 923  * character.
 924  */
 925 void strbuf_stripspace(struct strbuf *sb, int skip_comments)
 926 {
 927         int empties = 0;
 928         size_t i, j, len, newlen;
 929         char *eol;
 930
 931         /* We may have to add a newline. */
 932         strbuf_grow(sb, 1);
 933
 934         for (i = j = 0; i < sb->len; i += len, j += newlen) {
 935                 eol = memchr(sb->buf + i, '\n', sb->len - i);
 936                 len = eol ? eol - (sb->buf + i) + 1 : sb->len - i;
 937
 938                 if (skip_comments && len && sb->buf[i] == comment_line_char) {
 939                         newlen = 0;
 940                         continue;
 941                 }
 942                 newlen = cleanup(sb->buf + i, len);
 943
 944                 /* Not just an empty line? */
 945                 if (newlen) {
 946                         if (empties > 0 && j > 0)
 947                                 sb->buf[j++] = '\n';
 948                         empties = 0;
 949                         memmove(sb->buf + j, sb->buf + i, newlen);
 950                         sb->buf[newlen + j++] = '\n';
 951                 } else {
 952                         empties++;
 953                 }
 954         }
 955
 956         strbuf_setlen(sb, j);
 957 }
 958
 959 int strbuf_normalize_path(struct strbuf *src)
 960 {
 961         struct strbuf dst = STRBUF_INIT;
 962
 963         strbuf_grow(&dst, src->len);
 964         if (normalize_path_copy(dst.buf, src->buf) < 0) {
 965                 strbuf_release(&dst);
 966                 return -1;
 967         }
 968
 969         /*
 970          * normalize_path does not tell us the new length, so we have to
 971          * compute it by looking for the new NUL it placed
 972          */
 973         strbuf_setlen(&dst, strlen(dst.buf));
 974         strbuf_swap(src, &dst);
 975         strbuf_release(&dst);
 976         return 0;
 977 }