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v0.5.1
Revision b2c2e4c22c6a4fe151f02380d247cf3d9a9d5d1e authored by Jakub Narebski on 24 January 2010, 18:05:23 UTC, committed by Junio C Hamano on 25 January 2010, 01:48:08 UTC
In Internet Explorer 8 (IE8) the 'blame_incremental' view, which uses
JavaScript to generate blame info using AJAX, sometimes hang at the
beginning (at 0%) of blaming, e.g. for larger files with long history
like git's own gitweb/gitweb.perl.

The error shown by JavaScript console is "Unspecified error" at char:2
of the following line in gitweb/gitweb.js:

  if (xhr.readyState === 3 && xhr.status !== 200) {

Debugging it using IE8 JScript debuger shown that the error occurs
when trying to access xhr.status (xhr is XMLHttpRequest object).
Watch for xhr object shows 'Unspecified error.' as "value" of
xhr.status, and trying to access xhr.status from console throws error.

This bug is some intermittent bug, depending on XMLHttpRequest timing,
as it doesn't occur in all cases.  It is probably caused by the fact
that handleResponse is called from timer (pollTimer), to work around
the fact that some browsers call onreadystatechange handler only once
for each state change, and not like required for 'blame_incremental'
as soon as new data is available from server.  It looks like xhr
object is not properly initialized; still it is a bug to throw an
error when accessing xhr.status (and not use 'null' or 'undefined' as
value).

Work around this bug in IE8 by using try-catch block when accessing
xhr.status.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 026680f
Raw File
base85.c
#include "cache.h"

#undef DEBUG_85

#ifdef DEBUG_85
#define say(a) fprintf(stderr, a)
#define say1(a,b) fprintf(stderr, a, b)
#define say2(a,b,c) fprintf(stderr, a, b, c)
#else
#define say(a) do {} while(0)
#define say1(a,b) do {} while(0)
#define say2(a,b,c) do {} while(0)
#endif

static const char en85[] = {
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
	'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
	'U', 'V', 'W', 'X', 'Y', 'Z',
	'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
	'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
	'u', 'v', 'w', 'x', 'y', 'z',
	'!', '#', '$', '%', '&', '(', ')', '*', '+', '-',
	';', '<', '=', '>', '?', '@', '^', '_',	'`', '{',
	'|', '}', '~'
};

static char de85[256];
static void prep_base85(void)
{
	int i;
	if (de85['Z'])
		return;
	for (i = 0; i < ARRAY_SIZE(en85); i++) {
		int ch = en85[i];
		de85[ch] = i + 1;
	}
}

int decode_85(char *dst, const char *buffer, int len)
{
	prep_base85();

	say2("decode 85 <%.*s>", len/4*5, buffer);
	while (len) {
		unsigned acc = 0;
		int de, cnt = 4;
		unsigned char ch;
		do {
			ch = *buffer++;
			de = de85[ch];
			if (--de < 0)
				return error("invalid base85 alphabet %c", ch);
			acc = acc * 85 + de;
		} while (--cnt);
		ch = *buffer++;
		de = de85[ch];
		if (--de < 0)
			return error("invalid base85 alphabet %c", ch);
		/* Detect overflow. */
		if (0xffffffff / 85 < acc ||
		    0xffffffff - de < (acc *= 85))
			return error("invalid base85 sequence %.5s", buffer-5);
		acc += de;
		say1(" %08x", acc);

		cnt = (len < 4) ? len : 4;
		len -= cnt;
		do {
			acc = (acc << 8) | (acc >> 24);
			*dst++ = acc;
		} while (--cnt);
	}
	say("\n");

	return 0;
}

void encode_85(char *buf, const unsigned char *data, int bytes)
{
	say("encode 85");
	while (bytes) {
		unsigned acc = 0;
		int cnt;
		for (cnt = 24; cnt >= 0; cnt -= 8) {
			unsigned ch = *data++;
			acc |= ch << cnt;
			if (--bytes == 0)
				break;
		}
		say1(" %08x", acc);
		for (cnt = 4; cnt >= 0; cnt--) {
			int val = acc % 85;
			acc /= 85;
			buf[cnt] = en85[val];
		}
		buf += 5;
	}
	say("\n");

	*buf = 0;
}

#ifdef DEBUG_85
int main(int ac, char **av)
{
	char buf[1024];

	if (!strcmp(av[1], "-e")) {
		int len = strlen(av[2]);
		encode_85(buf, av[2], len);
		if (len <= 26) len = len + 'A' - 1;
		else len = len + 'a' - 26 - 1;
		printf("encoded: %c%s\n", len, buf);
		return 0;
	}
	if (!strcmp(av[1], "-d")) {
		int len = *av[2];
		if ('A' <= len && len <= 'Z') len = len - 'A' + 1;
		else len = len - 'a' + 26 + 1;
		decode_85(buf, av[2]+1, len);
		printf("decoded: %.*s\n", len, buf);
		return 0;
	}
	if (!strcmp(av[1], "-t")) {
		char t[4] = { -1,-1,-1,-1 };
		encode_85(buf, t, 4);
		printf("encoded: D%s\n", buf);
		return 0;
	}
}
#endif
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