git/utf8.c
Junio C Hamano dde843e737 utf8-bom: introduce skip_utf8_bom() helper
With the recent change to ignore the UTF8 BOM at the beginning of
.gitignore files, we now have two codepaths that do such a skipping
(the other one is for reading the configuration files).

Introduce utf8_bom[] constant string and skip_utf8_bom() helper
and teach .gitignore code how to use it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-16 11:35:06 -07:00

647 lines
15 KiB
C

#include "git-compat-util.h"
#include "strbuf.h"
#include "utf8.h"
/* This code is originally from http://www.cl.cam.ac.uk/~mgk25/ucs/ */
struct interval {
ucs_char_t first;
ucs_char_t last;
};
size_t display_mode_esc_sequence_len(const char *s)
{
const char *p = s;
if (*p++ != '\033')
return 0;
if (*p++ != '[')
return 0;
while (isdigit(*p) || *p == ';')
p++;
if (*p++ != 'm')
return 0;
return p - s;
}
/* auxiliary function for binary search in interval table */
static int bisearch(ucs_char_t ucs, const struct interval *table, int max)
{
int min = 0;
int mid;
if (ucs < table[0].first || ucs > table[max].last)
return 0;
while (max >= min) {
mid = (min + max) / 2;
if (ucs > table[mid].last)
min = mid + 1;
else if (ucs < table[mid].first)
max = mid - 1;
else
return 1;
}
return 0;
}
/* The following two functions define the column width of an ISO 10646
* character as follows:
*
* - The null character (U+0000) has a column width of 0.
*
* - Other C0/C1 control characters and DEL will lead to a return
* value of -1.
*
* - Non-spacing and enclosing combining characters (general
* category code Mn or Me in the Unicode database) have a
* column width of 0.
*
* - SOFT HYPHEN (U+00AD) has a column width of 1.
*
* - Other format characters (general category code Cf in the Unicode
* database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
*
* - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
* have a column width of 0.
*
* - Spacing characters in the East Asian Wide (W) or East Asian
* Full-width (F) category as defined in Unicode Technical
* Report #11 have a column width of 2.
*
* - All remaining characters (including all printable
* ISO 8859-1 and WGL4 characters, Unicode control characters,
* etc.) have a column width of 1.
*
* This implementation assumes that ucs_char_t characters are encoded
* in ISO 10646.
*/
static int git_wcwidth(ucs_char_t ch)
{
/*
* Sorted list of non-overlapping intervals of non-spacing characters,
*/
#include "unicode_width.h"
/* test for 8-bit control characters */
if (ch == 0)
return 0;
if (ch < 32 || (ch >= 0x7f && ch < 0xa0))
return -1;
/* binary search in table of non-spacing characters */
if (bisearch(ch, zero_width, sizeof(zero_width)
/ sizeof(struct interval) - 1))
return 0;
/* binary search in table of double width characters */
if (bisearch(ch, double_width, sizeof(double_width)
/ sizeof(struct interval) - 1))
return 2;
return 1;
}
/*
* Pick one ucs character starting from the location *start points at,
* and return it, while updating the *start pointer to point at the
* end of that character. When remainder_p is not NULL, the location
* holds the number of bytes remaining in the string that we are allowed
* to pick from. Otherwise we are allowed to pick up to the NUL that
* would eventually appear in the string. *remainder_p is also reduced
* by the number of bytes we have consumed.
*
* If the string was not a valid UTF-8, *start pointer is set to NULL
* and the return value is undefined.
*/
static ucs_char_t pick_one_utf8_char(const char **start, size_t *remainder_p)
{
unsigned char *s = (unsigned char *)*start;
ucs_char_t ch;
size_t remainder, incr;
/*
* A caller that assumes NUL terminated text can choose
* not to bother with the remainder length. We will
* stop at the first NUL.
*/
remainder = (remainder_p ? *remainder_p : 999);
if (remainder < 1) {
goto invalid;
} else if (*s < 0x80) {
/* 0xxxxxxx */
ch = *s;
incr = 1;
} else if ((s[0] & 0xe0) == 0xc0) {
/* 110XXXXx 10xxxxxx */
if (remainder < 2 ||
(s[1] & 0xc0) != 0x80 ||
(s[0] & 0xfe) == 0xc0)
goto invalid;
ch = ((s[0] & 0x1f) << 6) | (s[1] & 0x3f);
incr = 2;
} else if ((s[0] & 0xf0) == 0xe0) {
/* 1110XXXX 10Xxxxxx 10xxxxxx */
if (remainder < 3 ||
(s[1] & 0xc0) != 0x80 ||
(s[2] & 0xc0) != 0x80 ||
/* overlong? */
(s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) ||
/* surrogate? */
(s[0] == 0xed && (s[1] & 0xe0) == 0xa0) ||
/* U+FFFE or U+FFFF? */
(s[0] == 0xef && s[1] == 0xbf &&
(s[2] & 0xfe) == 0xbe))
goto invalid;
ch = ((s[0] & 0x0f) << 12) |
((s[1] & 0x3f) << 6) | (s[2] & 0x3f);
incr = 3;
} else if ((s[0] & 0xf8) == 0xf0) {
/* 11110XXX 10XXxxxx 10xxxxxx 10xxxxxx */
if (remainder < 4 ||
(s[1] & 0xc0) != 0x80 ||
(s[2] & 0xc0) != 0x80 ||
(s[3] & 0xc0) != 0x80 ||
/* overlong? */
(s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) ||
/* > U+10FFFF? */
(s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4)
goto invalid;
ch = ((s[0] & 0x07) << 18) | ((s[1] & 0x3f) << 12) |
((s[2] & 0x3f) << 6) | (s[3] & 0x3f);
incr = 4;
} else {
invalid:
*start = NULL;
return 0;
}
*start += incr;
if (remainder_p)
*remainder_p = remainder - incr;
return ch;
}
/*
* This function returns the number of columns occupied by the character
* pointed to by the variable start. The pointer is updated to point at
* the next character. When remainder_p is not NULL, it points at the
* location that stores the number of remaining bytes we can use to pick
* a character (see pick_one_utf8_char() above).
*/
int utf8_width(const char **start, size_t *remainder_p)
{
ucs_char_t ch = pick_one_utf8_char(start, remainder_p);
if (!*start)
return 0;
return git_wcwidth(ch);
}
/*
* Returns the total number of columns required by a null-terminated
* string, assuming that the string is utf8. Returns strlen() instead
* if the string does not look like a valid utf8 string.
*/
int utf8_strnwidth(const char *string, int len, int skip_ansi)
{
int width = 0;
const char *orig = string;
if (len == -1)
len = strlen(string);
while (string && string < orig + len) {
int skip;
while (skip_ansi &&
(skip = display_mode_esc_sequence_len(string)) != 0)
string += skip;
width += utf8_width(&string, NULL);
}
return string ? width : len;
}
int utf8_strwidth(const char *string)
{
return utf8_strnwidth(string, -1, 0);
}
int is_utf8(const char *text)
{
while (*text) {
if (*text == '\n' || *text == '\t' || *text == '\r') {
text++;
continue;
}
utf8_width(&text, NULL);
if (!text)
return 0;
}
return 1;
}
static void strbuf_add_indented_text(struct strbuf *buf, const char *text,
int indent, int indent2)
{
if (indent < 0)
indent = 0;
while (*text) {
const char *eol = strchrnul(text, '\n');
if (*eol == '\n')
eol++;
strbuf_addchars(buf, ' ', indent);
strbuf_add(buf, text, eol - text);
text = eol;
indent = indent2;
}
}
/*
* Wrap the text, if necessary. The variable indent is the indent for the
* first line, indent2 is the indent for all other lines.
* If indent is negative, assume that already -indent columns have been
* consumed (and no extra indent is necessary for the first line).
*/
void strbuf_add_wrapped_text(struct strbuf *buf,
const char *text, int indent1, int indent2, int width)
{
int indent, w, assume_utf8 = 1;
const char *bol, *space, *start = text;
size_t orig_len = buf->len;
if (width <= 0) {
strbuf_add_indented_text(buf, text, indent1, indent2);
return;
}
retry:
bol = text;
w = indent = indent1;
space = NULL;
if (indent < 0) {
w = -indent;
space = text;
}
for (;;) {
char c;
size_t skip;
while ((skip = display_mode_esc_sequence_len(text)))
text += skip;
c = *text;
if (!c || isspace(c)) {
if (w <= width || !space) {
const char *start = bol;
if (!c && text == start)
return;
if (space)
start = space;
else
strbuf_addchars(buf, ' ', indent);
strbuf_add(buf, start, text - start);
if (!c)
return;
space = text;
if (c == '\t')
w |= 0x07;
else if (c == '\n') {
space++;
if (*space == '\n') {
strbuf_addch(buf, '\n');
goto new_line;
}
else if (!isalnum(*space))
goto new_line;
else
strbuf_addch(buf, ' ');
}
w++;
text++;
}
else {
new_line:
strbuf_addch(buf, '\n');
text = bol = space + isspace(*space);
space = NULL;
w = indent = indent2;
}
continue;
}
if (assume_utf8) {
w += utf8_width(&text, NULL);
if (!text) {
assume_utf8 = 0;
text = start;
strbuf_setlen(buf, orig_len);
goto retry;
}
} else {
w++;
text++;
}
}
}
void strbuf_add_wrapped_bytes(struct strbuf *buf, const char *data, int len,
int indent, int indent2, int width)
{
char *tmp = xstrndup(data, len);
strbuf_add_wrapped_text(buf, tmp, indent, indent2, width);
free(tmp);
}
void strbuf_utf8_replace(struct strbuf *sb_src, int pos, int width,
const char *subst)
{
struct strbuf sb_dst = STRBUF_INIT;
char *src = sb_src->buf;
char *end = src + sb_src->len;
char *dst;
int w = 0, subst_len = 0;
if (subst)
subst_len = strlen(subst);
strbuf_grow(&sb_dst, sb_src->len + subst_len);
dst = sb_dst.buf;
while (src < end) {
char *old;
size_t n;
while ((n = display_mode_esc_sequence_len(src))) {
memcpy(dst, src, n);
src += n;
dst += n;
}
if (src >= end)
break;
old = src;
n = utf8_width((const char**)&src, NULL);
if (!src) /* broken utf-8, do nothing */
return;
if (n && w >= pos && w < pos + width) {
if (subst) {
memcpy(dst, subst, subst_len);
dst += subst_len;
subst = NULL;
}
w += n;
continue;
}
memcpy(dst, old, src - old);
dst += src - old;
w += n;
}
strbuf_setlen(&sb_dst, dst - sb_dst.buf);
strbuf_swap(sb_src, &sb_dst);
strbuf_release(&sb_dst);
}
int is_encoding_utf8(const char *name)
{
if (!name)
return 1;
if (!strcasecmp(name, "utf-8") || !strcasecmp(name, "utf8"))
return 1;
return 0;
}
int same_encoding(const char *src, const char *dst)
{
if (is_encoding_utf8(src) && is_encoding_utf8(dst))
return 1;
return !strcasecmp(src, dst);
}
/*
* Wrapper for fprintf and returns the total number of columns required
* for the printed string, assuming that the string is utf8.
*/
int utf8_fprintf(FILE *stream, const char *format, ...)
{
struct strbuf buf = STRBUF_INIT;
va_list arg;
int columns;
va_start(arg, format);
strbuf_vaddf(&buf, format, arg);
va_end(arg);
columns = fputs(buf.buf, stream);
if (0 <= columns) /* keep the error from the I/O */
columns = utf8_strwidth(buf.buf);
strbuf_release(&buf);
return columns;
}
/*
* Given a buffer and its encoding, return it re-encoded
* with iconv. If the conversion fails, returns NULL.
*/
#ifndef NO_ICONV
#if defined(OLD_ICONV) || (defined(__sun__) && !defined(_XPG6))
typedef const char * iconv_ibp;
#else
typedef char * iconv_ibp;
#endif
char *reencode_string_iconv(const char *in, size_t insz, iconv_t conv, int *outsz_p)
{
size_t outsz, outalloc;
char *out, *outpos;
iconv_ibp cp;
outsz = insz;
outalloc = outsz + 1; /* for terminating NUL */
out = xmalloc(outalloc);
outpos = out;
cp = (iconv_ibp)in;
while (1) {
size_t cnt = iconv(conv, &cp, &insz, &outpos, &outsz);
if (cnt == (size_t) -1) {
size_t sofar;
if (errno != E2BIG) {
free(out);
return NULL;
}
/* insz has remaining number of bytes.
* since we started outsz the same as insz,
* it is likely that insz is not enough for
* converting the rest.
*/
sofar = outpos - out;
outalloc = sofar + insz * 2 + 32;
out = xrealloc(out, outalloc);
outpos = out + sofar;
outsz = outalloc - sofar - 1;
}
else {
*outpos = '\0';
if (outsz_p)
*outsz_p = outpos - out;
break;
}
}
return out;
}
char *reencode_string_len(const char *in, int insz,
const char *out_encoding, const char *in_encoding,
int *outsz)
{
iconv_t conv;
char *out;
if (!in_encoding)
return NULL;
conv = iconv_open(out_encoding, in_encoding);
if (conv == (iconv_t) -1) {
/*
* Some platforms do not have the variously spelled variants of
* UTF-8, so let's fall back to trying the most official
* spelling. We do so only as a fallback in case the platform
* does understand the user's spelling, but not our official
* one.
*/
if (is_encoding_utf8(in_encoding))
in_encoding = "UTF-8";
if (is_encoding_utf8(out_encoding))
out_encoding = "UTF-8";
conv = iconv_open(out_encoding, in_encoding);
if (conv == (iconv_t) -1)
return NULL;
}
out = reencode_string_iconv(in, insz, conv, outsz);
iconv_close(conv);
return out;
}
#endif
/*
* Returns first character length in bytes for multi-byte `text` according to
* `encoding`.
*
* - The `text` pointer is updated to point at the next character.
* - When `remainder_p` is not NULL, on entry `*remainder_p` is how much bytes
* we can consume from text, and on exit `*remainder_p` is reduced by returned
* character length. Otherwise `text` is treated as limited by NUL.
*/
int mbs_chrlen(const char **text, size_t *remainder_p, const char *encoding)
{
int chrlen;
const char *p = *text;
size_t r = (remainder_p ? *remainder_p : SIZE_MAX);
if (r < 1)
return 0;
if (is_encoding_utf8(encoding)) {
pick_one_utf8_char(&p, &r);
chrlen = p ? (p - *text)
: 1 /* not valid UTF-8 -> raw byte sequence */;
}
else {
/*
* TODO use iconv to decode one char and obtain its chrlen
* for now, let's treat encodings != UTF-8 as one-byte
*/
chrlen = 1;
}
*text += chrlen;
if (remainder_p)
*remainder_p -= chrlen;
return chrlen;
}
/*
* Pick the next char from the stream, ignoring codepoints an HFS+ would.
* Note that this is _not_ complete by any means. It's just enough
* to make is_hfs_dotgit() work, and should not be used otherwise.
*/
static ucs_char_t next_hfs_char(const char **in)
{
while (1) {
ucs_char_t out = pick_one_utf8_char(in, NULL);
/*
* check for malformed utf8. Technically this
* gets converted to a percent-sequence, but
* returning 0 is good enough for is_hfs_dotgit
* to realize it cannot be .git
*/
if (!*in)
return 0;
/* these code points are ignored completely */
switch (out) {
case 0x200c: /* ZERO WIDTH NON-JOINER */
case 0x200d: /* ZERO WIDTH JOINER */
case 0x200e: /* LEFT-TO-RIGHT MARK */
case 0x200f: /* RIGHT-TO-LEFT MARK */
case 0x202a: /* LEFT-TO-RIGHT EMBEDDING */
case 0x202b: /* RIGHT-TO-LEFT EMBEDDING */
case 0x202c: /* POP DIRECTIONAL FORMATTING */
case 0x202d: /* LEFT-TO-RIGHT OVERRIDE */
case 0x202e: /* RIGHT-TO-LEFT OVERRIDE */
case 0x206a: /* INHIBIT SYMMETRIC SWAPPING */
case 0x206b: /* ACTIVATE SYMMETRIC SWAPPING */
case 0x206c: /* INHIBIT ARABIC FORM SHAPING */
case 0x206d: /* ACTIVATE ARABIC FORM SHAPING */
case 0x206e: /* NATIONAL DIGIT SHAPES */
case 0x206f: /* NOMINAL DIGIT SHAPES */
case 0xfeff: /* ZERO WIDTH NO-BREAK SPACE */
continue;
}
return out;
}
}
int is_hfs_dotgit(const char *path)
{
ucs_char_t c;
c = next_hfs_char(&path);
if (c != '.')
return 0;
c = next_hfs_char(&path);
/*
* there's a great deal of other case-folding that occurs
* in HFS+, but this is enough to catch anything that will
* convert to ".git"
*/
if (c != 'g' && c != 'G')
return 0;
c = next_hfs_char(&path);
if (c != 'i' && c != 'I')
return 0;
c = next_hfs_char(&path);
if (c != 't' && c != 'T')
return 0;
c = next_hfs_char(&path);
if (c && !is_dir_sep(c))
return 0;
return 1;
}
const char utf8_bom[] = "\357\273\277";
int skip_utf8_bom(char **text, size_t len)
{
if (len < strlen(utf8_bom) ||
memcmp(*text, utf8_bom, strlen(utf8_bom)))
return 0;
*text += strlen(utf8_bom);
return 1;
}