string_bytes: Guarantee valid utf-8 output

Previously v8's WriteUtf8 function would produce invalid utf-8 output
when encountering unmatched surrogate code units [1]. The new
REPLACE_INVALID_UTF8 option fixes that by replacing invalid code points
with the unicode replacement character.

[1]: JS Strings are defined as arrays of 16 bit unsigned integers. There
is no unicode enforcement, so one can easily end up with invalid unicode
code unit sequences inside a string.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/string_bytes.h b/src/string_bytes.h
index 8071a494ae9..31f04bbe4b3 100644
--- a/src/string_bytes.h
+++ b/src/string_bytes.h
@@ -29,6 +29,8 @@
 
 namespace node {
 
+extern int WRITE_UTF8_FLAGS;
+
 using v8::Handle;
 using v8::Local;
 using v8::String;