Port internal class QXmlUtils to QStringView

... and adapt callers.

In one case, port a use of QString::toLatin1() to QStringRef::
toLatin1() so together with this change and the addition of
QString::arg(QStringView) we can drop one more QStringRef::toString().

Change-Id: Iba898af8cc2a9e1a811e271789359395f595ad32
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

4 files changed, 23 insertions, 28 deletions

diff --git a/src/corelib/xml/qxmlstream.cpp b/src/corelib/xml/qxmlstream.cpp
index ecca5569f8..3d600c2380 100644
--- a/src/corelib/xml/qxmlstream.cpp
+++ b/src/corelib/xml/qxmlstream.cpp
@@ -1798,18 +1798,17 @@ void QXmlStreamReaderPrivate::startDocument()
         QStringRef value(symString(attrib.value));
 
         if (prefix.isEmpty() && key == QLatin1String("encoding")) {
-            const QString name(value.toString());
             documentEncoding = value;
 
             if(hasStandalone)
                 err = QXmlStream::tr("The standalone pseudo attribute must appear after the encoding.");
-            if(!QXmlUtils::isEncName(name))
+            if (!QXmlUtils::isEncName(value))
                 err = QXmlStream::tr("%1 is an invalid encoding name.").arg(value);
             else {
 #ifdef QT_NO_TEXTCODEC
                 readBuffer = QString::fromLatin1(rawReadBuffer.data(), nbytesread);
 #else
-                QTextCodec *const newCodec = QTextCodec::codecForName(name.toLatin1());
+                QTextCodec *const newCodec = QTextCodec::codecForName(value.toLatin1());
                 if (!newCodec)
                     err = QXmlStream::tr("Encoding %1 is unsupported").arg(value);
                 else if (newCodec != codec && !lockEncoding) {
diff --git a/src/corelib/xml/qxmlstream_p.h b/src/corelib/xml/qxmlstream_p.h
index b62cc9ac39..1edd716094 100644
--- a/src/corelib/xml/qxmlstream_p.h
+++ b/src/corelib/xml/qxmlstream_p.h
@@ -1636,7 +1636,7 @@ bool QXmlStreamReaderPrivate::parse()
         break;
 
         case 175: {
-            if (!QXmlUtils::isPublicID(symString(1).toString())) {
+            if (!QXmlUtils::isPublicID(symString(1))) {
                 raiseWellFormedError(QXmlStream::tr("%1 is an invalid PUBLIC identifier.").arg(symString(1).toString()));
                 resume(175);
                 return false;
diff --git a/src/corelib/xml/qxmlutils.cpp b/src/corelib/xml/qxmlutils.cpp
index 23caae2935..01c84251fd 100644
--- a/src/corelib/xml/qxmlutils.cpp
+++ b/src/corelib/xml/qxmlutils.cpp
@@ -227,19 +227,22 @@ bool QXmlUtils::isBaseChar(const QChar c)
     \sa {http://www.w3.org/TR/REC-xml/#NT-EncName},
            {Extensible Markup Language (XML) 1.0 (Fourth Edition), [81] EncName}
  */
-bool QXmlUtils::isEncName(const QString &encName)
+bool QXmlUtils::isEncName(QStringView encName)
 {
     // Valid encoding names are given by "[A-Za-z][A-Za-z0-9._\\-]*"
-    const ushort *c = encName.utf16();
-    int l = encName.length();
-    if (l < 1 || !((c[0] >= 'a' && c[0] <= 'z') || (c[0] >= 'A' && c[0] <= 'Z')))
+    if (encName.isEmpty())
         return false;
-    for (int i = 1; i < l; ++i) {
-        if ((c[i] >= 'a' && c[i] <= 'z')
-            || (c[i] >= 'A' && c[i] <= 'Z')
-            || (c[i] >= '0' && c[i] <= '9')
-            || c[i] == '.' || c[i] == '_' || c[i] == '-')
+    const auto first = encName.front().unicode();
+    if (!((first >= 'a' && first <= 'z') || (first >= 'A' && first <= 'Z')))
+        return false;
+    for (QChar ch : encName.mid(1)) {
+        const auto cp = ch.unicode();
+        if ((cp >= 'a' && cp <= 'z')
+            || (cp >= 'A' && cp <= 'Z')
+            || (cp >= '0' && cp <= '9')
+            || cp == '.' || cp == '_' || cp == '-') {
             continue;
+        }
         return false;
     }
     return true;
@@ -310,13 +313,10 @@ bool QXmlUtils::isNameChar(const QChar c)
     \sa {http://www.w3.org/TR/REC-xml/#NT-PubidLiteral},
            {Extensible Markup Language (XML) 1.0 (Fourth Edition), [12] PubidLiteral}
  */
-bool QXmlUtils::isPublicID(const QString &candidate)
+bool QXmlUtils::isPublicID(QStringView candidate)
 {
-    const int len = candidate.length();
-
-    for(int i = 0; i < len; ++i)
-    {
-        const ushort cp = candidate.at(i).unicode();
+    for (QChar ch : candidate) {
+        const ushort cp = ch.unicode();
 
         if ((cp >= 'a' && cp <= 'z')
             || (cp >= 'A' && cp <= 'Z')
@@ -369,7 +369,7 @@ bool QXmlUtils::isPublicID(const QString &candidate)
     \sa {http://www.w3.org/TR/REC-xml-names/#NT-NCName},
            {W3CNamespaces in XML 1.0 (Second Edition), [4] NCName}
  */
-bool QXmlUtils::isNCName(const QStringRef &ncName)
+bool QXmlUtils::isNCName(QStringView ncName)
 {
     if(ncName.isEmpty())
         return false;
@@ -379,10 +379,7 @@ bool QXmlUtils::isNCName(const QStringRef &ncName)
     if(!QXmlUtils::isLetter(first) && first.unicode() != '_' && first.unicode() != ':')
         return false;
 
-    const int len = ncName.size();
-    for(int i = 0; i < len; ++i)
-    {
-        const QChar at = ncName.at(i);
+    for (QChar at : ncName) {
         if(!QXmlUtils::isNameChar(at) || at == QLatin1Char(':'))
             return false;
     }
diff --git a/src/corelib/xml/qxmlutils_p.h b/src/corelib/xml/qxmlutils_p.h
index 6db347b3ee..db6bddd5be 100644
--- a/src/corelib/xml/qxmlutils_p.h
+++ b/src/corelib/xml/qxmlutils_p.h
@@ -68,13 +68,12 @@ class QXmlCharRange;
 class Q_CORE_EXPORT QXmlUtils
 {
 public:
-    static bool isEncName(const QString &encName);
+    static bool isEncName(QStringView encName);
     static bool isChar(const QChar c);
     static bool isNameChar(const QChar c);
     static bool isLetter(const QChar c);
-    static bool isNCName(const QStringRef &ncName);
-    static inline bool isNCName(const QString &ncName) { return isNCName(QStringRef(&ncName)); }
-    static bool isPublicID(const QString &candidate);
+    static bool isNCName(QStringView ncName);
+    static bool isPublicID(QStringView candidate);
 
 private:
     typedef const QXmlCharRange *RangeIter;