From 1b89a480bf4f4c91d16f6cdc31d77de34701237c Mon Sep 17 00:00:00 2001
From: Fedor <fedor@mail.ru>
Date: Thu, 16 Jul 2020 03:54:23 +0300
Subject: [PATCH] [js] Improve readability and control flow of js date string
 parser.

---
 js/src/jsdate.cpp | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/js/src/jsdate.cpp b/js/src/jsdate.cpp
index c6a369e2d..41722ffa9 100644
--- a/js/src/jsdate.cpp
+++ b/js/src/jsdate.cpp
@@ -21,6 +21,8 @@
 #include "mozilla/FloatingPoint.h"
 #include "mozilla/Sprintf.h"
 
+#include "nsCRT.h"
+
 #include <ctype.h>
 #include <math.h>
 #include <string.h>
@@ -958,11 +960,20 @@ ParseDate(const CharT* s, size_t length, ClippedTime* result)
     while (i < length) {
         int c = s[i];
         i++;
-        if (c <= ' ' || c == ',' || c == '-') {
-            if (c == '-' && '0' <= s[i] && s[i] <= '9')
+        
+        // Spaces, ASCII control characters, and commas are ignored.
+        if (c <= ' ' || c == ',')
+            continue;
+
+        // Dashes are delimiters if they're immediately followed by a number field.
+        // If they're not followed by a number field, they're simply ignored.
+        if (c == '-') {
+            if (i < length && nsCRT::IsAsciiDigit(s[i])) {
                 prevc = c;
+            }
             continue;
         }
+
         if (c == '(') { /* comments) */
             int depth = 1;
             while (i < length) {
@@ -977,7 +988,9 @@ ParseDate(const CharT* s, size_t length, ClippedTime* result)
             }
             continue;
         }
-        if ('0' <= c && c <= '9') {
+
+        // Parse a number field.
+        if (nsCRT::IsAsciiDigit(c)) {        
             int n = c - '0';
             while (i < length && '0' <= (c = s[i]) && c <= '9') {
                 n = n * 10 + c - '0';