Avoid using QString when converting headers between WTF::String and QByteArray

We should not convert Latin1 to UTF16 and back for each header of each
HTTP request and response. In older WebKit versions String was always
16-bit, but now 8-bit is used wherever possible, and this is usually the
case for HTTP headers.

Change-Id: I642f65c614702aca4ad7a673f5073a8eaed5b46d
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

2 files changed, 14 insertions, 7 deletions

diff --git a/Source/WebCore/platform/network/qt/QNetworkReplyHandler.cpp b/Source/WebCore/platform/network/qt/QNetworkReplyHandler.cpp
index e07bc76a9..4a2121907 100644
--- a/Source/WebCore/platform/network/qt/QNetworkReplyHandler.cpp
+++ b/Source/WebCore/platform/network/qt/QNetworkReplyHandler.cpp
@@ -601,7 +601,8 @@ void QNetworkReplyHandler::sendResponseIfNeeded()
     int statusCode = m_replyWrapper->reply()->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
 
     if (url.protocolIsInHTTPFamily()) {
-        String suggestedFilename = filenameFromHTTPContentDisposition(QString::fromLatin1(m_replyWrapper->reply()->rawHeader("Content-Disposition")));
+        QByteArray contentDisposition = m_replyWrapper->reply()->rawHeader("Content-Disposition");
+        String suggestedFilename = filenameFromHTTPContentDisposition(String(contentDisposition.constData(), contentDisposition.size()));
 
         if (!suggestedFilename.isEmpty())
             response.setSuggestedFilename(suggestedFilename);
@@ -626,7 +627,7 @@ void QNetworkReplyHandler::sendResponseIfNeeded()
 
         // Add remaining headers.
         foreach (const QNetworkReply::RawHeaderPair& pair, m_replyWrapper->reply()->rawHeaderPairs())
-            response.setHTTPHeaderField(QString::fromLatin1(pair.first), QString::fromLatin1(pair.second));
+            response.setHTTPHeaderField(String(pair.first.constData(), pair.first.size()), String(pair.second.constData(), pair.second.size()));
     }
 
     QUrl redirection = m_replyWrapper->reply()->attribute(QNetworkRequest::RedirectionTargetAttribute).toUrl();
diff --git a/Source/WebCore/platform/network/qt/ResourceRequestQt.cpp b/Source/WebCore/platform/network/qt/ResourceRequestQt.cpp
index 46229027e..83c50062d 100644
--- a/Source/WebCore/platform/network/qt/ResourceRequestQt.cpp
+++ b/Source/WebCore/platform/network/qt/ResourceRequestQt.cpp
@@ -89,6 +89,13 @@ static void resolveBlobUrl(const QUrl& url, QUrl& resolvedUrl)
 }
 #endif
 
+static inline QByteArray stringToByteArray(const String& string)
+{
+    if (string.is8Bit())
+        return QByteArray(reinterpret_cast<const char*>(string.characters8()), string.length());
+    return QString(string).toLatin1();
+}
+
 QNetworkRequest ResourceRequest::toNetworkRequest(NetworkingContext *context) const
 {
     QNetworkRequest request;
@@ -105,14 +112,13 @@ QNetworkRequest ResourceRequest::toNetworkRequest(NetworkingContext *context) co
     const HTTPHeaderMap &headers = httpHeaderFields();
     for (HTTPHeaderMap::const_iterator it = headers.begin(), end = headers.end();
          it != end; ++it) {
-        QByteArray name = QString(it->key).toLatin1();
-        QByteArray value = QString(it->value).toLatin1();
+        QByteArray name = stringToByteArray(it->key);
         // QNetworkRequest::setRawHeader() would remove the header if the value is null
         // Make sure to set an empty header instead of null header.
-        if (!value.isNull())
-            request.setRawHeader(name, value);
+        if (!it->value.isNull())
+            request.setRawHeader(name, stringToByteArray(it->value));
         else
-            request.setRawHeader(name, "");
+            request.setRawHeader(name, QByteArrayLiteral(""));
     }
 
     // Make sure we always have an Accept header; some sites require this to