JNI: implement support for native functions taking a list

This didn't work yet because the partial specialization of the
JNITypeForArgImpl factory was missing. Add a test case for
QJniArray<double> and QList<double>.

What doesn't work (yet) is QStringList for a native Java function
taking a String[]. That will be added in a follow-up commit.

Change-Id: I4d3fa0ecc04b98b9749f8358792f86c02ddbbc14
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

src/corelib/kernel/qjnitypes.h

@@ -95,6 +95,33 @@ struct JNITypeForArgImpl<QString>
     }
 };
 
+template <typename T>
+struct JNITypeForArgImpl<QJniArray<T>>
+{
+    using Type = jobject;
+
+    static QJniArray<T> fromVarArg(Type t)
+    {
+        return QJniArray<T>(t);
+    }
+};
+
+template <typename T>
+struct JNITypeForArgImpl<QList<T>>
+{
+private:
+    using ArrayType = decltype(QJniArrayBase::fromContainer(std::declval<QList<T>>()));
+    using ArrayObjectType = decltype(std::declval<ArrayType>().arrayObject());
+    using ElementType = typename ArrayType::value_type;
+public:
+    using Type = ArrayObjectType;
+
+    static QList<T> fromVarArg(Type t)
+    {
+        return QJniArray<ElementType>(t).toContainer();
+    }
+};
+
 template <typename Arg>
 using JNITypeForArg = typename JNITypeForArgImpl<std::decay_t<Arg>>::Type;
 template <typename Arg, typename Type>

tests/auto/corelib/kernel/qjniobject/testdata/src/org/qtproject/qt/android/testdata/QtJniObjectTestClass.java

@@ -281,6 +281,8 @@ public class QtJniObjectTestClass
     native public int callbackWithBoolean(boolean value);
     native public int callbackWithInt(int value);
     native public int callbackWithDouble(double value);
+    native public int callbackWithJniArray(double[] value);
+    native public int callbackWithQList(double[] value);
 
     public int callMeBackWithObject(QtJniObjectTestClass that)
     {
@@ -316,4 +318,12 @@ public class QtJniObjectTestClass
     {
         return callbackWithDouble(value);
     }
+    public int callMeBackWithJniArray(double[] value)
+    {
+        return callbackWithJniArray(value);
+    }
+    public int callMeBackWithQList(double[] value)
+    {
+        return callbackWithQList(value);
+    }
 }

tests/auto/corelib/kernel/qjniobject/tst_qjniobject.cpp

@@ -1871,7 +1871,9 @@ enum class CallbackParameterType
     Byte,
     Boolean,
     Int,
-    Double
+    Double,
+    JniArray,
+    QList,
 };
 
 static std::optional<TestClass> calledWithObject;
@@ -1928,6 +1930,22 @@ static int callbackWithDouble(JNIEnv *, jobject, double value)
 }
 Q_DECLARE_JNI_NATIVE_METHOD(callbackWithDouble)
 
+static std::optional<QJniArray<jdouble>> calledWithJniArray;
+static int callbackWithJniArray(JNIEnv *, jobject, const QJniArray<jdouble> &value)
+{
+    calledWithJniArray.emplace(value);
+    return int(CallbackParameterType::JniArray);
+}
+Q_DECLARE_JNI_NATIVE_METHOD(callbackWithJniArray)
+
+static std::optional<QList<double>> calledWithQList;
+static int callbackWithQList(JNIEnv *, jobject, const QList<double> &value)
+{
+    calledWithQList.emplace(value);
+    return int(CallbackParameterType::QList);
+}
+Q_DECLARE_JNI_NATIVE_METHOD(callbackWithQList)
+
 void tst_QJniObject::callback_data()
 {
     QTest::addColumn<CallbackParameterType>("parameterType");
@@ -1939,6 +1957,8 @@ void tst_QJniObject::callback_data()
     QTest::addRow("Boolean")    << CallbackParameterType::Boolean;
     QTest::addRow("Int")        << CallbackParameterType::Int;
     QTest::addRow("Double")     << CallbackParameterType::Double;
+    QTest::addRow("JniArray")   << CallbackParameterType::JniArray;
+    QTest::addRow("QList")      << CallbackParameterType::QList;
 }
 
 void tst_QJniObject::callback()
@@ -2005,6 +2025,26 @@ void tst_QJniObject::callback()
         QVERIFY(calledWithDouble);
         QCOMPARE(calledWithDouble.value(), 1.2345);
         break;
+    case CallbackParameterType::JniArray: {
+        QVERIFY(TestClass::registerNativeMethods({
+            Q_JNI_NATIVE_METHOD(callbackWithJniArray)
+        }));
+        const QJniArray<double> doubles = QJniArrayBase::fromContainer(QList<double>{ 1.2, 3.4, 5.6 });
+        result = testObject.callMethod<int>("callMeBackWithJniArray", doubles);
+        QVERIFY(calledWithJniArray);
+        QCOMPARE(calledWithJniArray, doubles);
+        break;
+    }
+    case CallbackParameterType::QList: {
+        QVERIFY(TestClass::registerNativeMethods({
+            Q_JNI_NATIVE_METHOD(callbackWithQList)
+        }));
+        const QList<double> doubles = { 1.2, 3.4, 5.6 };
+        result = testObject.callMethod<int>("callMeBackWithQList", doubles);
+        QVERIFY(calledWithQList);
+        QCOMPARE(calledWithQList.value(), doubles);
+        break;
+    }
     }
     QCOMPARE(result, int(parameterType));
 }