Fixed RegExp.prototype.exec() with global regexp and unicode input.

Previously, when exactly 32 characters unicode string was provided and
the "lastIndex" value of "this" regexp was equal to 32 too, the
njs_string_utf8_offset() was called with invalid index argument (longer
than a size of the string).  As a result njs_string_utf8_offset()
returned garbage values.

This was manifested in the following ways:
1) InternalError: pcre2_match() failed: bad offset value

2) Very slow replace calls with global regexps, for
   example in expressions like: str.replace(/<re>/g).

This fixes #677 on Github.

diff --git a/src/njs_regexp.c b/src/njs_regexp.c
index 970041d6283d95e5dba7e19a641330eb7f89ca03..e61bf54ceaa2bfdcdd366d59c99c2757ff368ac8 100644 (file)
--- a/src/njs_regexp.c
+++ b/src/njs_regexp.c
@@ -936,9 +936,14 @@ njs_regexp_builtin_exec(njs_vm_t *vm, njs_value_t *r, njs_value_t *s,
         offset = last_index;
 
     } else {
-        offset = njs_string_utf8_offset(string.start,
-                                        string.start + string.size, last_index)
-                 - string.start;
+        if ((size_t) last_index < string.length) {
+            offset = njs_string_utf8_offset(string.start,
+                                            string.start + string.size,
+                                            last_index)
+                     - string.start;
+        } else {
+            offset = string.size;
+        }
     }
 
     ret = njs_regexp_match(vm, &pattern->regex[type], string.start, offset,

diff --git a/src/test/njs_unit_test.c b/src/test/njs_unit_test.c
index fbe9043eb54888397bbc0f47010773606699308d..bec1f53f0f80be63e293f09e7693976787241cf3 100644 (file)
--- a/src/test/njs_unit_test.c
+++ b/src/test/njs_unit_test.c
@@ -9261,6 +9261,12 @@ static njs_unit_test_t  njs_test[] =
     { njs_str("'abc'.replaceAll(/^/g, '|$&|')"),
       njs_str("||abc") },
 
+    { njs_str("('α'.repeat(30) + 'aa').replace(/a/g, '#')"),
+      njs_str("αααααααααααααααααααααααααααααα##") },
+
+    { njs_str("('α'.repeat(30) + 'aa').replaceAll(/a/g, '#')"),
+      njs_str("αααααααααααααααααααααααααααααα##") },
+
     { njs_str("var uri ='/u/v1/Aa/bB?type=m3u8&mt=42';"
               "uri.replace(/^\\/u\\/v1\\/[^/]*\\/([^\?]*)\\?.*(mt=[^&]*).*$/, '$1|$2')"),
       njs_str("bB|mt=42") },