git/strbuf.c
Junio C Hamano 0c493966ff Merge branch 'rs/strbuf-getwholeline-fix'
A helper function to read a single whole line into strbuf
mistakenly triggered OOM error at EOF under certain conditions,
which has been fixed.

* rs/strbuf-getwholeline-fix:
  strbuf: clear errno before calling getdelim(3)
2017-08-22 10:29:15 -07:00

941 lines
20 KiB
C

#include "cache.h"
#include "refs.h"
#include "utf8.h"
int starts_with(const char *str, const char *prefix)
{
for (; ; str++, prefix++)
if (!*prefix)
return 1;
else if (*str != *prefix)
return 0;
}
/*
* Used as the default ->buf value, so that people can always assume
* buf is non NULL and ->buf is NUL terminated even for a freshly
* initialized strbuf.
*/
char strbuf_slopbuf[1];
void strbuf_init(struct strbuf *sb, size_t hint)
{
sb->alloc = sb->len = 0;
sb->buf = strbuf_slopbuf;
if (hint)
strbuf_grow(sb, hint);
}
void strbuf_release(struct strbuf *sb)
{
if (sb->alloc) {
free(sb->buf);
strbuf_init(sb, 0);
}
}
char *strbuf_detach(struct strbuf *sb, size_t *sz)
{
char *res;
strbuf_grow(sb, 0);
res = sb->buf;
if (sz)
*sz = sb->len;
strbuf_init(sb, 0);
return res;
}
void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc)
{
strbuf_release(sb);
sb->buf = buf;
sb->len = len;
sb->alloc = alloc;
strbuf_grow(sb, 0);
sb->buf[sb->len] = '\0';
}
void strbuf_grow(struct strbuf *sb, size_t extra)
{
int new_buf = !sb->alloc;
if (unsigned_add_overflows(extra, 1) ||
unsigned_add_overflows(sb->len, extra + 1))
die("you want to use way too much memory");
if (new_buf)
sb->buf = NULL;
ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
if (new_buf)
sb->buf[0] = '\0';
}
void strbuf_trim(struct strbuf *sb)
{
strbuf_rtrim(sb);
strbuf_ltrim(sb);
}
void strbuf_rtrim(struct strbuf *sb)
{
while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
sb->len--;
sb->buf[sb->len] = '\0';
}
void strbuf_ltrim(struct strbuf *sb)
{
char *b = sb->buf;
while (sb->len > 0 && isspace(*b)) {
b++;
sb->len--;
}
memmove(sb->buf, b, sb->len);
sb->buf[sb->len] = '\0';
}
int strbuf_reencode(struct strbuf *sb, const char *from, const char *to)
{
char *out;
int len;
if (same_encoding(from, to))
return 0;
out = reencode_string_len(sb->buf, sb->len, to, from, &len);
if (!out)
return -1;
strbuf_attach(sb, out, len, len);
return 0;
}
void strbuf_tolower(struct strbuf *sb)
{
char *p = sb->buf, *end = sb->buf + sb->len;
for (; p < end; p++)
*p = tolower(*p);
}
struct strbuf **strbuf_split_buf(const char *str, size_t slen,
int terminator, int max)
{
struct strbuf **ret = NULL;
size_t nr = 0, alloc = 0;
struct strbuf *t;
while (slen) {
int len = slen;
if (max <= 0 || nr + 1 < max) {
const char *end = memchr(str, terminator, slen);
if (end)
len = end - str + 1;
}
t = xmalloc(sizeof(struct strbuf));
strbuf_init(t, len);
strbuf_add(t, str, len);
ALLOC_GROW(ret, nr + 2, alloc);
ret[nr++] = t;
str += len;
slen -= len;
}
ALLOC_GROW(ret, nr + 1, alloc); /* In case string was empty */
ret[nr] = NULL;
return ret;
}
void strbuf_list_free(struct strbuf **sbs)
{
struct strbuf **s = sbs;
while (*s) {
strbuf_release(*s);
free(*s++);
}
free(sbs);
}
int strbuf_cmp(const struct strbuf *a, const struct strbuf *b)
{
int len = a->len < b->len ? a->len: b->len;
int cmp = memcmp(a->buf, b->buf, len);
if (cmp)
return cmp;
return a->len < b->len ? -1: a->len != b->len;
}
void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
const void *data, size_t dlen)
{
if (unsigned_add_overflows(pos, len))
die("you want to use way too much memory");
if (pos > sb->len)
die("`pos' is too far after the end of the buffer");
if (pos + len > sb->len)
die("`pos + len' is too far after the end of the buffer");
if (dlen >= len)
strbuf_grow(sb, dlen - len);
memmove(sb->buf + pos + dlen,
sb->buf + pos + len,
sb->len - pos - len);
memcpy(sb->buf + pos, data, dlen);
strbuf_setlen(sb, sb->len + dlen - len);
}
void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len)
{
strbuf_splice(sb, pos, 0, data, len);
}
void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
{
strbuf_splice(sb, pos, len, "", 0);
}
void strbuf_add(struct strbuf *sb, const void *data, size_t len)
{
strbuf_grow(sb, len);
memcpy(sb->buf + sb->len, data, len);
strbuf_setlen(sb, sb->len + len);
}
void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
{
strbuf_grow(sb, sb2->len);
memcpy(sb->buf + sb->len, sb2->buf, sb2->len);
strbuf_setlen(sb, sb->len + sb2->len);
}
void strbuf_addchars(struct strbuf *sb, int c, size_t n)
{
strbuf_grow(sb, n);
memset(sb->buf + sb->len, c, n);
strbuf_setlen(sb, sb->len + n);
}
void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
strbuf_vaddf(sb, fmt, ap);
va_end(ap);
}
static void add_lines(struct strbuf *out,
const char *prefix1,
const char *prefix2,
const char *buf, size_t size)
{
while (size) {
const char *prefix;
const char *next = memchr(buf, '\n', size);
next = next ? (next + 1) : (buf + size);
prefix = ((prefix2 && (buf[0] == '\n' || buf[0] == '\t'))
? prefix2 : prefix1);
strbuf_addstr(out, prefix);
strbuf_add(out, buf, next - buf);
size -= next - buf;
buf = next;
}
strbuf_complete_line(out);
}
void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size)
{
static char prefix1[3];
static char prefix2[2];
if (prefix1[0] != comment_line_char) {
xsnprintf(prefix1, sizeof(prefix1), "%c ", comment_line_char);
xsnprintf(prefix2, sizeof(prefix2), "%c", comment_line_char);
}
add_lines(out, prefix1, prefix2, buf, size);
}
void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...)
{
va_list params;
struct strbuf buf = STRBUF_INIT;
int incomplete_line = sb->len && sb->buf[sb->len - 1] != '\n';
va_start(params, fmt);
strbuf_vaddf(&buf, fmt, params);
va_end(params);
strbuf_add_commented_lines(sb, buf.buf, buf.len);
if (incomplete_line)
sb->buf[--sb->len] = '\0';
strbuf_release(&buf);
}
void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap)
{
int len;
va_list cp;
if (!strbuf_avail(sb))
strbuf_grow(sb, 64);
va_copy(cp, ap);
len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, cp);
va_end(cp);
if (len < 0)
die("BUG: your vsnprintf is broken (returned %d)", len);
if (len > strbuf_avail(sb)) {
strbuf_grow(sb, len);
len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
if (len > strbuf_avail(sb))
die("BUG: your vsnprintf is broken (insatiable)");
}
strbuf_setlen(sb, sb->len + len);
}
void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
void *context)
{
for (;;) {
const char *percent;
size_t consumed;
percent = strchrnul(format, '%');
strbuf_add(sb, format, percent - format);
if (!*percent)
break;
format = percent + 1;
if (*format == '%') {
strbuf_addch(sb, '%');
format++;
continue;
}
consumed = fn(sb, format, context);
if (consumed)
format += consumed;
else
strbuf_addch(sb, '%');
}
}
size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,
void *context)
{
struct strbuf_expand_dict_entry *e = context;
size_t len;
for (; e->placeholder && (len = strlen(e->placeholder)); e++) {
if (!strncmp(placeholder, e->placeholder, len)) {
if (e->value)
strbuf_addstr(sb, e->value);
return len;
}
}
return 0;
}
void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src)
{
int i, len = src->len;
for (i = 0; i < len; i++) {
if (src->buf[i] == '%')
strbuf_addch(dst, '%');
strbuf_addch(dst, src->buf[i]);
}
}
size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
{
size_t res;
size_t oldalloc = sb->alloc;
strbuf_grow(sb, size);
res = fread(sb->buf + sb->len, 1, size, f);
if (res > 0)
strbuf_setlen(sb, sb->len + res);
else if (oldalloc == 0)
strbuf_release(sb);
return res;
}
ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
{
size_t oldlen = sb->len;
size_t oldalloc = sb->alloc;
strbuf_grow(sb, hint ? hint : 8192);
for (;;) {
ssize_t want = sb->alloc - sb->len - 1;
ssize_t got = read_in_full(fd, sb->buf + sb->len, want);
if (got < 0) {
if (oldalloc == 0)
strbuf_release(sb);
else
strbuf_setlen(sb, oldlen);
return -1;
}
sb->len += got;
if (got < want)
break;
strbuf_grow(sb, 8192);
}
sb->buf[sb->len] = '\0';
return sb->len - oldlen;
}
ssize_t strbuf_read_once(struct strbuf *sb, int fd, size_t hint)
{
ssize_t cnt;
strbuf_grow(sb, hint ? hint : 8192);
cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
if (cnt > 0)
strbuf_setlen(sb, sb->len + cnt);
return cnt;
}
ssize_t strbuf_write(struct strbuf *sb, FILE *f)
{
return sb->len ? fwrite(sb->buf, 1, sb->len, f) : 0;
}
#define STRBUF_MAXLINK (2*PATH_MAX)
int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
{
size_t oldalloc = sb->alloc;
if (hint < 32)
hint = 32;
while (hint < STRBUF_MAXLINK) {
int len;
strbuf_grow(sb, hint);
len = readlink(path, sb->buf, hint);
if (len < 0) {
if (errno != ERANGE)
break;
} else if (len < hint) {
strbuf_setlen(sb, len);
return 0;
}
/* .. the buffer was too small - try again */
hint *= 2;
}
if (oldalloc == 0)
strbuf_release(sb);
return -1;
}
int strbuf_getcwd(struct strbuf *sb)
{
size_t oldalloc = sb->alloc;
size_t guessed_len = 128;
for (;; guessed_len *= 2) {
strbuf_grow(sb, guessed_len);
if (getcwd(sb->buf, sb->alloc)) {
strbuf_setlen(sb, strlen(sb->buf));
return 0;
}
/*
* If getcwd(3) is implemented as a syscall that falls
* back to a regular lookup using readdir(3) etc. then
* we may be able to avoid EACCES by providing enough
* space to the syscall as it's not necessarily bound
* to the same restrictions as the fallback.
*/
if (errno == EACCES && guessed_len < PATH_MAX)
continue;
if (errno != ERANGE)
break;
}
if (oldalloc == 0)
strbuf_release(sb);
else
strbuf_reset(sb);
return -1;
}
#ifdef HAVE_GETDELIM
int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
{
ssize_t r;
if (feof(fp))
return EOF;
strbuf_reset(sb);
/* Translate slopbuf to NULL, as we cannot call realloc on it */
if (!sb->alloc)
sb->buf = NULL;
errno = 0;
r = getdelim(&sb->buf, &sb->alloc, term, fp);
if (r > 0) {
sb->len = r;
return 0;
}
assert(r == -1);
/*
* Normally we would have called xrealloc, which will try to free
* memory and recover. But we have no way to tell getdelim() to do so.
* Worse, we cannot try to recover ENOMEM ourselves, because we have
* no idea how many bytes were read by getdelim.
*
* Dying here is reasonable. It mirrors what xrealloc would do on
* catastrophic memory failure. We skip the opportunity to free pack
* memory and retry, but that's unlikely to help for a malloc small
* enough to hold a single line of input, anyway.
*/
if (errno == ENOMEM)
die("Out of memory, getdelim failed");
/*
* Restore strbuf invariants; if getdelim left us with a NULL pointer,
* we can just re-init, but otherwise we should make sure that our
* length is empty, and that the result is NUL-terminated.
*/
if (!sb->buf)
strbuf_init(sb, 0);
else
strbuf_reset(sb);
return EOF;
}
#else
int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
{
int ch;
if (feof(fp))
return EOF;
strbuf_reset(sb);
flockfile(fp);
while ((ch = getc_unlocked(fp)) != EOF) {
if (!strbuf_avail(sb))
strbuf_grow(sb, 1);
sb->buf[sb->len++] = ch;
if (ch == term)
break;
}
funlockfile(fp);
if (ch == EOF && sb->len == 0)
return EOF;
sb->buf[sb->len] = '\0';
return 0;
}
#endif
static int strbuf_getdelim(struct strbuf *sb, FILE *fp, int term)
{
if (strbuf_getwholeline(sb, fp, term))
return EOF;
if (sb->buf[sb->len - 1] == term)
strbuf_setlen(sb, sb->len - 1);
return 0;
}
int strbuf_getline(struct strbuf *sb, FILE *fp)
{
if (strbuf_getwholeline(sb, fp, '\n'))
return EOF;
if (sb->buf[sb->len - 1] == '\n') {
strbuf_setlen(sb, sb->len - 1);
if (sb->len && sb->buf[sb->len - 1] == '\r')
strbuf_setlen(sb, sb->len - 1);
}
return 0;
}
int strbuf_getline_lf(struct strbuf *sb, FILE *fp)
{
return strbuf_getdelim(sb, fp, '\n');
}
int strbuf_getline_nul(struct strbuf *sb, FILE *fp)
{
return strbuf_getdelim(sb, fp, '\0');
}
int strbuf_getwholeline_fd(struct strbuf *sb, int fd, int term)
{
strbuf_reset(sb);
while (1) {
char ch;
ssize_t len = xread(fd, &ch, 1);
if (len <= 0)
return EOF;
strbuf_addch(sb, ch);
if (ch == term)
break;
}
return 0;
}
ssize_t strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
{
int fd;
ssize_t len;
fd = open(path, O_RDONLY);
if (fd < 0)
return -1;
len = strbuf_read(sb, fd, hint);
close(fd);
if (len < 0)
return -1;
return len;
}
void strbuf_add_lines(struct strbuf *out, const char *prefix,
const char *buf, size_t size)
{
add_lines(out, prefix, NULL, buf, size);
}
void strbuf_addstr_xml_quoted(struct strbuf *buf, const char *s)
{
while (*s) {
size_t len = strcspn(s, "\"<>&");
strbuf_add(buf, s, len);
s += len;
switch (*s) {
case '"':
strbuf_addstr(buf, "&quot;");
break;
case '<':
strbuf_addstr(buf, "&lt;");
break;
case '>':
strbuf_addstr(buf, "&gt;");
break;
case '&':
strbuf_addstr(buf, "&amp;");
break;
case 0:
return;
}
s++;
}
}
static int is_rfc3986_reserved(char ch)
{
switch (ch) {
case '!': case '*': case '\'': case '(': case ')': case ';':
case ':': case '@': case '&': case '=': case '+': case '$':
case ',': case '/': case '?': case '#': case '[': case ']':
return 1;
}
return 0;
}
static int is_rfc3986_unreserved(char ch)
{
return isalnum(ch) ||
ch == '-' || ch == '_' || ch == '.' || ch == '~';
}
static void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
int reserved)
{
strbuf_grow(sb, len);
while (len--) {
char ch = *s++;
if (is_rfc3986_unreserved(ch) ||
(!reserved && is_rfc3986_reserved(ch)))
strbuf_addch(sb, ch);
else
strbuf_addf(sb, "%%%02x", ch);
}
}
void strbuf_addstr_urlencode(struct strbuf *sb, const char *s,
int reserved)
{
strbuf_add_urlencode(sb, s, strlen(s), reserved);
}
void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes)
{
if (bytes > 1 << 30) {
strbuf_addf(buf, "%u.%2.2u GiB",
(int)(bytes >> 30),
(int)(bytes & ((1 << 30) - 1)) / 10737419);
} else if (bytes > 1 << 20) {
int x = bytes + 5243; /* for rounding */
strbuf_addf(buf, "%u.%2.2u MiB",
x >> 20, ((x & ((1 << 20) - 1)) * 100) >> 20);
} else if (bytes > 1 << 10) {
int x = bytes + 5; /* for rounding */
strbuf_addf(buf, "%u.%2.2u KiB",
x >> 10, ((x & ((1 << 10) - 1)) * 100) >> 10);
} else {
strbuf_addf(buf, "%u bytes", (int)bytes);
}
}
void strbuf_add_absolute_path(struct strbuf *sb, const char *path)
{
if (!*path)
die("The empty string is not a valid path");
if (!is_absolute_path(path)) {
struct stat cwd_stat, pwd_stat;
size_t orig_len = sb->len;
char *cwd = xgetcwd();
char *pwd = getenv("PWD");
if (pwd && strcmp(pwd, cwd) &&
!stat(cwd, &cwd_stat) &&
(cwd_stat.st_dev || cwd_stat.st_ino) &&
!stat(pwd, &pwd_stat) &&
pwd_stat.st_dev == cwd_stat.st_dev &&
pwd_stat.st_ino == cwd_stat.st_ino)
strbuf_addstr(sb, pwd);
else
strbuf_addstr(sb, cwd);
if (sb->len > orig_len && !is_dir_sep(sb->buf[sb->len - 1]))
strbuf_addch(sb, '/');
free(cwd);
}
strbuf_addstr(sb, path);
}
void strbuf_add_real_path(struct strbuf *sb, const char *path)
{
if (sb->len) {
struct strbuf resolved = STRBUF_INIT;
strbuf_realpath(&resolved, path, 1);
strbuf_addbuf(sb, &resolved);
strbuf_release(&resolved);
} else
strbuf_realpath(sb, path, 1);
}
int printf_ln(const char *fmt, ...)
{
int ret;
va_list ap;
va_start(ap, fmt);
ret = vprintf(fmt, ap);
va_end(ap);
if (ret < 0 || putchar('\n') == EOF)
return -1;
return ret + 1;
}
int fprintf_ln(FILE *fp, const char *fmt, ...)
{
int ret;
va_list ap;
va_start(ap, fmt);
ret = vfprintf(fp, fmt, ap);
va_end(ap);
if (ret < 0 || putc('\n', fp) == EOF)
return -1;
return ret + 1;
}
char *xstrdup_tolower(const char *string)
{
char *result;
size_t len, i;
len = strlen(string);
result = xmallocz(len);
for (i = 0; i < len; i++)
result[i] = tolower(string[i]);
result[i] = '\0';
return result;
}
char *xstrvfmt(const char *fmt, va_list ap)
{
struct strbuf buf = STRBUF_INIT;
strbuf_vaddf(&buf, fmt, ap);
return strbuf_detach(&buf, NULL);
}
char *xstrfmt(const char *fmt, ...)
{
va_list ap;
char *ret;
va_start(ap, fmt);
ret = xstrvfmt(fmt, ap);
va_end(ap);
return ret;
}
void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm,
int tz_offset, int suppress_tz_name)
{
struct strbuf munged_fmt = STRBUF_INIT;
size_t hint = 128;
size_t len;
if (!*fmt)
return;
/*
* There is no portable way to pass timezone information to
* strftime, so we handle %z and %Z here.
*/
for (;;) {
const char *percent = strchrnul(fmt, '%');
strbuf_add(&munged_fmt, fmt, percent - fmt);
if (!*percent)
break;
fmt = percent + 1;
switch (*fmt) {
case '%':
strbuf_addstr(&munged_fmt, "%%");
fmt++;
break;
case 'z':
strbuf_addf(&munged_fmt, "%+05d", tz_offset);
fmt++;
break;
case 'Z':
if (suppress_tz_name) {
fmt++;
break;
}
/* FALLTHROUGH */
default:
strbuf_addch(&munged_fmt, '%');
}
}
fmt = munged_fmt.buf;
strbuf_grow(sb, hint);
len = strftime(sb->buf + sb->len, sb->alloc - sb->len, fmt, tm);
if (!len) {
/*
* strftime reports "0" if it could not fit the result in the buffer.
* Unfortunately, it also reports "0" if the requested time string
* takes 0 bytes. So our strategy is to munge the format so that the
* output contains at least one character, and then drop the extra
* character before returning.
*/
strbuf_addch(&munged_fmt, ' ');
while (!len) {
hint *= 2;
strbuf_grow(sb, hint);
len = strftime(sb->buf + sb->len, sb->alloc - sb->len,
munged_fmt.buf, tm);
}
len--; /* drop munged space */
}
strbuf_release(&munged_fmt);
strbuf_setlen(sb, sb->len + len);
}
void strbuf_add_unique_abbrev(struct strbuf *sb, const unsigned char *sha1,
int abbrev_len)
{
int r;
strbuf_grow(sb, GIT_SHA1_HEXSZ + 1);
r = find_unique_abbrev_r(sb->buf + sb->len, sha1, abbrev_len);
strbuf_setlen(sb, sb->len + r);
}
/*
* Returns the length of a line, without trailing spaces.
*
* If the line ends with newline, it will be removed too.
*/
static size_t cleanup(char *line, size_t len)
{
while (len) {
unsigned char c = line[len - 1];
if (!isspace(c))
break;
len--;
}
return len;
}
/*
* Remove empty lines from the beginning and end
* and also trailing spaces from every line.
*
* Turn multiple consecutive empty lines between paragraphs
* into just one empty line.
*
* If the input has only empty lines and spaces,
* no output will be produced.
*
* If last line does not have a newline at the end, one is added.
*
* Enable skip_comments to skip every line starting with comment
* character.
*/
void strbuf_stripspace(struct strbuf *sb, int skip_comments)
{
int empties = 0;
size_t i, j, len, newlen;
char *eol;
/* We may have to add a newline. */
strbuf_grow(sb, 1);
for (i = j = 0; i < sb->len; i += len, j += newlen) {
eol = memchr(sb->buf + i, '\n', sb->len - i);
len = eol ? eol - (sb->buf + i) + 1 : sb->len - i;
if (skip_comments && len && sb->buf[i] == comment_line_char) {
newlen = 0;
continue;
}
newlen = cleanup(sb->buf + i, len);
/* Not just an empty line? */
if (newlen) {
if (empties > 0 && j > 0)
sb->buf[j++] = '\n';
empties = 0;
memmove(sb->buf + j, sb->buf + i, newlen);
sb->buf[newlen + j++] = '\n';
} else {
empties++;
}
}
strbuf_setlen(sb, j);
}
int strbuf_normalize_path(struct strbuf *src)
{
struct strbuf dst = STRBUF_INIT;
strbuf_grow(&dst, src->len);
if (normalize_path_copy(dst.buf, src->buf) < 0) {
strbuf_release(&dst);
return -1;
}
/*
* normalize_path does not tell us the new length, so we have to
* compute it by looking for the new NUL it placed
*/
strbuf_setlen(&dst, strlen(dst.buf));
strbuf_swap(src, &dst);
strbuf_release(&dst);
return 0;
}