fix encoding detection in StreamFilter

1 files changed, 9 insertions, 4 deletions

diff --git a/background/stream_filter.js b/background/stream_filter.js
index 921523a..b7879ea 100644
--- a/background/stream_filter.js
+++ b/background/stream_filter.js
@@ -35,7 +35,7 @@
 function validate_encoding(charset)
 {
     try {
-	new TextDecoder();
+	new TextDecoder(charset);
 	return charset;
     } catch(e) {
 	return undefined;
@@ -44,7 +44,7 @@ function validate_encoding(charset)
 
 function is_content_type_header(header)
 {
-    header.name.toLowerCase().trim() === "content-type";
+    return header.name.toLowerCase().trim() === "content-type";
 }
 
 const charset_reg = /;\s*charset\s*=\s*([\w-]+)/i;
@@ -55,7 +55,8 @@ function properties_from_headers(headers)
 
     for (const header of headers.filter(is_content_type_header)) {
 	const match = charset_reg.exec(header.value);
-	if (!properties.detected_charset && validate_encoding(match[1]))
+	if (match && !properties.detected_charset &&
+	    validate_encoding(match[1]))
 	    properties.detected_charset = match[1];
 
 	if (/html/i.test(header.value))
@@ -105,7 +106,11 @@ function charset_from_meta_tags(doc)
 function create_decoder(properties, data)
 {
     let charset = charset_from_BOM(data) || properties.detected_charset;
-    if (!charset && data.indexOf(0) !== -1) {
+
+    if (charset)
+	return new TextDecoder(charset);
+
+    if (data.indexOf(0) !== -1) {
         console.warn("Haketilo: zeroes in bytestream, probable cached encoding mismatch. Trying to decode it as UTF-16.",
 		     properties);
 	return new TextDecoder("utf-16be");