json: Add operator[] to QJsonValue for implicit object and array access

Saves a lot of manual toArray() and toObject() calls when the
JSON structure is usually known anyways. Read only access for now.

Change-Id: I5fd787144198e0443e4da285a11ce2597b66f99f
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 30 insertions, 0 deletions

diff --git a/tests/auto/corelib/json/tst_qtjson.cpp b/tests/auto/corelib/json/tst_qtjson.cpp
index b215364f0e..32f68c4292 100644
--- a/tests/auto/corelib/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/json/tst_qtjson.cpp
@@ -145,6 +145,8 @@ private Q_SLOTS:
     void parseErrorOffset_data();
     void parseErrorOffset();
 
+    void implicitValueType();
+
 private:
     QString testDataDir;
 };
@@ -2908,5 +2910,33 @@ void tst_QtJson::parseErrorOffset()
     QCOMPARE(error.offset, errorOffset);
 }
 
+void tst_QtJson::implicitValueType()
+{
+    QJsonObject rootObject{
+        {"object", QJsonObject{{"value", 42}}},
+        {"array", QJsonArray{665, 666, 667}}
+    };
+
+    QJsonValue objectValue = rootObject["object"];
+    QCOMPARE(objectValue["value"].toInt(), 42);
+    QCOMPARE(objectValue["missingValue"], QJsonValue(QJsonValue::Undefined));
+    QCOMPARE(objectValue[123], QJsonValue(QJsonValue::Undefined));
+    QCOMPARE(objectValue["missingValue"].toInt(123), 123);
+
+    QJsonValue arrayValue = rootObject["array"];
+    QCOMPARE(arrayValue[1].toInt(), 666);
+    QCOMPARE(arrayValue[-1], QJsonValue(QJsonValue::Undefined));
+    QCOMPARE(arrayValue["asObject"], QJsonValue(QJsonValue::Undefined));
+    QCOMPARE(arrayValue[-1].toInt(123), 123);
+
+    const QJsonObject constObject = rootObject;
+    QCOMPARE(constObject["object"]["value"].toInt(), 42);
+    QCOMPARE(constObject["array"][1].toInt(), 666);
+
+    QJsonValue objectAsValue(rootObject);
+    QCOMPARE(objectAsValue["object"]["value"].toInt(), 42);
+    QCOMPARE(objectAsValue["array"][1].toInt(), 666);
+}
+
 QTEST_MAIN(tst_QtJson)
 #include "tst_qtjson.moc"