Add QMetaType::type(QByteArray) function

QMetaType::type(const char *) requires that the string argument is
0-terminated. This new overload makes it possible to query the type
of a string with an explicit length.

In particular, QByteArrays constructed by QByteArray::fromRawData(),
for example from a substring of a normalized method signature (the
"int" part of "mySlot(int"), can now be queried without making a copy
of the string.

Also, Qt5 meta-objects represent type names as QByteArray literals,
which can be fed directly to this new QMetaType::type() overload (no
need to call strlen).

Change-Id: I60d35aa6bdc0f77e0997f98b0e30e12fd3d5e100
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

4 files changed, 101 insertions, 6 deletions

diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index 311648c33a..4540e96de6 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -801,7 +801,7 @@ static inline int qMetaTypeStaticType(const char *typeName, int length)
 {
     int i = 0;
     while (types[i].typeName && ((length != types[i].typeNameLength)
-                                 || strcmp(typeName, types[i].typeName))) {
+                                 || memcmp(typeName, types[i].typeName, length))) {
         ++i;
     }
     return types[i].type;
@@ -821,7 +821,7 @@ static int qMetaTypeCustomType_unlocked(const char *typeName, int length)
     for (int v = 0; v < ct->count(); ++v) {
         const QCustomTypeInfo &customInfo = ct->at(v);
         if ((length == customInfo.typeName.size())
-            && !strcmp(typeName, customInfo.typeName.constData())) {
+            && !memcmp(typeName, customInfo.typeName.constData(), length)) {
             if (customInfo.alias >= 0)
                 return customInfo.alias;
             return v + QMetaType::User;
@@ -1048,9 +1048,8 @@ bool QMetaType::isRegistered(int type)
     Implementation of QMetaType::type().
 */
 template <bool tryNormalizedType>
-static inline int qMetaTypeTypeImpl(const char *typeName)
+static inline int qMetaTypeTypeImpl(const char *typeName, int length)
 {
-    int length = qstrlen(typeName);
     if (!length)
         return QMetaType::UnknownType;
     int type = qMetaTypeStaticType(typeName, length);
@@ -1080,7 +1079,7 @@ static inline int qMetaTypeTypeImpl(const char *typeName)
 */
 int QMetaType::type(const char *typeName)
 {
-    return qMetaTypeTypeImpl</*tryNormalizedType=*/true>(typeName);
+    return qMetaTypeTypeImpl</*tryNormalizedType=*/true>(typeName, qstrlen(typeName));
 }
 
 /*!
@@ -1092,7 +1091,21 @@ int QMetaType::type(const char *typeName)
 */
 int qMetaTypeTypeInternal(const char *typeName)
 {
-    return qMetaTypeTypeImpl</*tryNormalizedType=*/false>(typeName);
+    return qMetaTypeTypeImpl</*tryNormalizedType=*/false>(typeName, qstrlen(typeName));
+}
+
+/*!
+    \since 5.5
+    \overload
+
+    Returns a handle to the type called \a typeName, or 0 if there is
+    no such type.
+
+    \sa isRegistered(), typeName()
+*/
+int QMetaType::type(const QT_PREPEND_NAMESPACE(QByteArray) &typeName)
+{
+    return qMetaTypeTypeImpl</*tryNormalizedType=*/true>(typeName.constData(), typeName.size());
 }
 
 #ifndef QT_NO_DATASTREAM
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 08b2fb083a..947bf77796 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -472,6 +472,11 @@ public:
     static int registerTypedef(const char *typeName, int aliasId);
     static int registerNormalizedTypedef(const QT_PREPEND_NAMESPACE(QByteArray) &normalizedTypeName, int aliasId);
     static int type(const char *typeName);
+#ifndef Q_QDOC
+    static int type(const QT_PREPEND_NAMESPACE(QByteArray) &typeName);
+#else
+    static int type(const QByteArray &typeName);
+#endif
     static const char *typeName(int type);
     static int sizeOf(int type);
     static TypeFlags typeFlags(int type);
diff --git a/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp b/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp
index a35896283a..fa328de619 100644
--- a/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp
+++ b/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp
@@ -79,6 +79,10 @@ private slots:
     void normalizedTypes();
     void typeName_data();
     void typeName();
+    void type_data();
+    void type();
+    void type_fromSubString_data();
+    void type_fromSubString();
     void create_data();
     void create();
     void createCopy_data();
@@ -385,6 +389,61 @@ void tst_QMetaType::typeName()
     QCOMPARE(name.toLatin1(), QMetaObject::normalizedType(name.toLatin1().constData()));
 }
 
+void tst_QMetaType::type_data()
+{
+    QTest::addColumn<QMetaType::Type>("aType");
+    QTest::addColumn<QByteArray>("aTypeName");
+
+#define TST_QMETATYPE_TYPE_DATA(MetaTypeName, MetaTypeId, RealType)\
+    QTest::newRow(#RealType) << QMetaType::MetaTypeName << QByteArray( #RealType );
+#define TST_QMETATYPE_TYPE_DATA_ALIAS(MetaTypeName, MetaTypeId, AliasType, RealTypeString)\
+    QTest::newRow(RealTypeString) << QMetaType::MetaTypeName << QByteArray( #AliasType );
+
+    QTest::newRow("empty") << QMetaType::UnknownType << QByteArray();
+
+    QT_FOR_EACH_STATIC_TYPE(TST_QMETATYPE_TYPE_DATA)
+    QT_FOR_EACH_STATIC_ALIAS_TYPE(TST_QMETATYPE_TYPE_DATA_ALIAS)
+
+#undef TST_QMETATYPE_TYPE_DATA
+#undef TST_METATYPE_TYPE_DATA_ALIAS
+}
+
+void tst_QMetaType::type()
+{
+    QFETCH(QMetaType::Type, aType);
+    QFETCH(QByteArray, aTypeName);
+
+    // QMetaType::type(QByteArray)
+    QCOMPARE(QMetaType::type(aTypeName), int(aType));
+    // QMetaType::type(const char *)
+    QCOMPARE(QMetaType::type(aTypeName.constData()), int(aType));
+}
+
+void tst_QMetaType::type_fromSubString_data()
+{
+    QTest::addColumn<int>("offset");
+    QTest::addColumn<int>("size");
+    QTest::addColumn<int>("expectedType");
+
+    // The test string is defined in the test function below
+    QTest::newRow("int") << 0 << 3 << int(QMetaType::Int);
+    QTest::newRow("boo") << 3 << 3 << 0;
+    QTest::newRow("bool") << 3 << 4 << int(QMetaType::Bool);
+    QTest::newRow("intbool") << 0 << 7 << 0;
+    QTest::newRow("QMetaType::Type") << 7 << 15 << ::qMetaTypeId<QMetaType::Type>();
+    QTest::newRow("double") << 22 << 6 << int(QMetaType::Double);
+}
+
+void tst_QMetaType::type_fromSubString()
+{
+    static const char *types = "intboolQMetaType::Typedoublexxx";
+    QFETCH(int, offset);
+    QFETCH(int, size);
+    QFETCH(int, expectedType);
+    QByteArray ba = QByteArray::fromRawData(types + offset, size);
+    QCOMPARE(QMetaType::type(ba), expectedType);
+}
+
 #define FOR_EACH_PRIMITIVE_METATYPE(F) \
     QT_FOR_EACH_STATIC_PRIMITIVE_TYPE(F) \
     QT_FOR_EACH_STATIC_CORE_POINTER(F) \
diff --git a/tests/benchmarks/corelib/kernel/qmetatype/tst_qmetatype.cpp b/tests/benchmarks/corelib/kernel/qmetatype/tst_qmetatype.cpp
index 9403c3fbb4..53cf26d0f1 100644
--- a/tests/benchmarks/corelib/kernel/qmetatype/tst_qmetatype.cpp
+++ b/tests/benchmarks/corelib/kernel/qmetatype/tst_qmetatype.cpp
@@ -45,6 +45,8 @@ public:
 private slots:
     void typeBuiltin_data();
     void typeBuiltin();
+    void typeBuiltin_QByteArray_data();
+    void typeBuiltin_QByteArray();
     void typeBuiltinNotNormalized_data();
     void typeBuiltinNotNormalized();
     void typeCustom();
@@ -94,6 +96,7 @@ void tst_QMetaType::typeBuiltin_data()
     }
 }
 
+// QMetaType::type(const char *)
 void tst_QMetaType::typeBuiltin()
 {
     QFETCH(QByteArray, typeName);
@@ -104,6 +107,21 @@ void tst_QMetaType::typeBuiltin()
     }
 }
 
+void tst_QMetaType::typeBuiltin_QByteArray_data()
+{
+    typeBuiltin_data();
+}
+
+// QMetaType::type(QByteArray)
+void tst_QMetaType::typeBuiltin_QByteArray()
+{
+    QFETCH(QByteArray, typeName);
+    QBENCHMARK {
+        for (int i = 0; i < 100000; ++i)
+            QMetaType::type(typeName);
+    }
+}
+
 void tst_QMetaType::typeBuiltinNotNormalized_data()
 {
     QTest::addColumn<QByteArray>("typeName");