shithub: libmujs

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Check for cyclic structures in JSON.stringify.

--- a/json.c

+++ b/json.c

@@ -210,10 +210,15 @@

 {

 	const char *key;

 	int save;

-	int n = 0;

+	int i, n;

-	/* TODO: check stack for duplicate value (cyclical structure) */

+	n = js_gettop(J) - 1;

+	for (i = 4; i < n; ++i)

+		if (js_isobject(J, i))

+			if (js_toobject(J, i) == js_toobject(J, -1))

+				js_typeerror(J, "cyclic object value");

+	n = 0;

 	js_putc(J, sb, '{');

 	js_pushiterator(J, -1, 1);

 	while ((key = js_nextiterator(J, -1))) {

@@ -237,17 +242,21 @@

 static void fmtarray(js_State *J, js_Buffer **sb, const char *gap, int level)

 {

-	int n, k;

+	int n, i;

 	char buf[32];

-	/* TODO: check stack for duplicate value (cyclical structure) */

+	n = js_gettop(J) - 1;

+	for (i = 4; i < n; ++i)

+		if (js_isobject(J, i))

+			if (js_toobject(J, i) == js_toobject(J, -1))

+				js_typeerror(J, "cyclic object value");

 	js_putc(J, sb, '[');

 	n = js_getlength(J, -1);

-	for (k = 0; k < n; ++k) {

-		if (k) js_putc(J, sb, ',');

+	for (i = 0; i < n; ++i) {

+		if (i) js_putc(J, sb, ',');

 		if (gap) fmtindent(J, sb, gap, level + 1);

-		if (!fmtvalue(J, sb, js_itoa(buf, k), gap, level + 1))

+		if (!fmtvalue(J, sb, js_itoa(buf, i), gap, level + 1))

 			js_puts(J, sb, "null");

 	}

 	if (gap && n) fmtindent(J, sb, gap, level);