/*
* returns the display length of the word beginning s, using the
* specified encoding.
*/
int
PQdsplen(const char *s, int encoding)
{
return pg_encoding_dsplen(encoding, s);
}
/*
* Add an error-location display to the error message under construction.
*
* The cursor location is measured in logical characters; the query string
* is presumed to be in the specified encoding.
*/
static void
reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
{
#define DISPLAY_SIZE 60 /* screen width limit, in screen cols */
#define MIN_RIGHT_CUT 10 /* try to keep this far away from EOL */
char *wquery;
int slen,
cno,
i,
*qidx,
*scridx,
qoffset,
scroffset,
ibeg,
iend,
loc_line;
bool mb_encoding,
beg_trunc,
end_trunc;
/* Convert loc from 1-based to 0-based; no-op if out of range */
loc--;
if (loc < 0)
return;
/* Need a writable copy of the query */
wquery = strdup(query);
if (wquery == NULL)
return; /* fail silently if out of memory */
/*
* Each character might occupy multiple physical bytes in the string, and
* in some Far Eastern character sets it might take more than one screen
* column as well. We compute the starting byte offset and starting
* screen column of each logical character, and store these in qidx[] and
* scridx[] respectively.
*/
/* we need a safe allocation size... */
slen = strlen(wquery) + 1;
qidx = (int *) malloc(slen * sizeof(int));
if (qidx == NULL)
{
free(wquery);
return;
}
scridx = (int *) malloc(slen * sizeof(int));
if (scridx == NULL)
{
free(qidx);
free(wquery);
return;
}
/* We can optimize a bit if it's a single-byte encoding */
mb_encoding = (pg_encoding_max_length(encoding) != 1);
/*
* Within the scanning loop, cno is the current character's logical
* number, qoffset is its offset in wquery, and scroffset is its starting
* logical screen column (all indexed from 0). "loc" is the logical
* character number of the error location. We scan to determine loc_line
* (the 1-based line number containing loc) and ibeg/iend (first character
* number and last+1 character number of the line containing loc). Note
* that qidx[] and scridx[] are filled only as far as iend.
*/
qoffset = 0;
scroffset = 0;
loc_line = 1;
ibeg = 0;
iend = -1; /* -1 means not set yet */
for (cno = 0; wquery[qoffset] != '\0'; cno++)
{
char ch = wquery[qoffset];
qidx[cno] = qoffset;
scridx[cno] = scroffset;
/*
* Replace tabs with spaces in the writable copy. (Later we might
* want to think about coping with their variable screen width, but
* not today.)
*/
if (ch == '\t')
wquery[qoffset] = ' ';
/*
* If end-of-line, count lines and mark positions. Each \r or \n
* counts as a line except when \r \n appear together.
*/
else if (ch == '\r' || ch == '\n')
{
if (cno < loc)
{
if (ch == '\r' ||
cno == 0 ||
wquery[qidx[cno - 1]] != '\r')
loc_line++;
/* extract beginning = last line start before loc. */
ibeg = cno + 1;
}
else
{
/* set extract end. */
iend = cno;
/* done scanning. */
break;
}
}
/* Advance */
if (mb_encoding)
{
int w;
w = pg_encoding_dsplen(encoding, &wquery[qoffset]);
/* treat any non-tab control chars as width 1 */
if (w <= 0)
w = 1;
scroffset += w;
qoffset += pg_encoding_mblen(encoding, &wquery[qoffset]);
}
else
{
/* We assume wide chars only exist in multibyte encodings */
scroffset++;
qoffset++;
}
}
/* Fix up if we didn't find an end-of-line after loc */
if (iend < 0)
{
iend = cno; /* query length in chars, +1 */
qidx[iend] = qoffset;
scridx[iend] = scroffset;
}
/* Print only if loc is within computed query length */
if (loc <= cno)
{
/* If the line extracted is too long, we truncate it. */
beg_trunc = false;
end_trunc = false;
if (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
{
/*
* We first truncate right if it is enough. This code might be
* off a space or so on enforcing MIN_RIGHT_CUT if there's a wide
* character right there, but that should be okay.
*/
if (scridx[ibeg] + DISPLAY_SIZE >= scridx[loc] + MIN_RIGHT_CUT)
{
while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
iend--;
end_trunc = true;
}
else
{
/* Truncate right if not too close to loc. */
while (scridx[loc] + MIN_RIGHT_CUT < scridx[iend])
{
iend--;
end_trunc = true;
}
/* Truncate left if still too long. */
while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
{
ibeg++;
beg_trunc = true;
}
}
}
/* truncate working copy at desired endpoint */
wquery[qidx[iend]] = '\0';
/* Begin building the finished message. */
i = msg->len;
appendPQExpBuffer(msg, libpq_gettext("LINE %d: "), loc_line);
if (beg_trunc)
appendPQExpBufferStr(msg, "...");
/*
* While we have the prefix in the msg buffer, compute its screen
* width.
*/
scroffset = 0;
for (; i < msg->len; i += pg_encoding_mblen(encoding, &msg->data[i]))
{
int w = pg_encoding_dsplen(encoding, &msg->data[i]);
if (w <= 0)
w = 1;
scroffset += w;
}
/* Finish up the LINE message line. */
appendPQExpBufferStr(msg, &wquery[qidx[ibeg]]);
if (end_trunc)
appendPQExpBufferStr(msg, "...");
appendPQExpBufferChar(msg, '\n');
/* Now emit the cursor marker line. */
scroffset += scridx[loc] - scridx[ibeg];
for (i = 0; i < scroffset; i++)
appendPQExpBufferChar(msg, ' ');
appendPQExpBufferChar(msg, '^');
appendPQExpBufferChar(msg, '\n');
}
/* Clean up. */
free(scridx);
free(qidx);
free(wquery);
}