Handle errors when streaming QJsonDocument through QDataStream

Change-Id: I96df896d446e89dc4f9733a6cc6cec61a6826a1f
Reviewed-by: Luca Beldi <v.ronin@yahoo.it>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/serialization/qjsondocument.cpp

@@ -47,6 +47,7 @@
 #include "qjsonwriter_p.h"
 #include "qjsonparser_p.h"
 #include "qjson_p.h"
+#include "qdatastream.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -680,7 +681,10 @@ QDataStream &operator>>(QDataStream &stream, QJsonDocument &doc)
 {
     QByteArray buffer;
     stream >> buffer;
-    doc = QJsonDocument::fromJson(buffer);
+    QJsonParseError parseError{};
+    doc = QJsonDocument::fromJson(buffer, &parseError);
+    if (parseError.error && !buffer.isEmpty())
+        stream.setStatus(QDataStream::ReadCorruptData);
     return stream;
 }
 #endif

tests/auto/corelib/serialization/qdatastream/tst_qdatastream.cpp

@@ -135,6 +135,8 @@ private slots:
 
     void stream_QByteArray2();
 
+    void stream_QJsonDocument();
+
     void setVersion_data();
     void setVersion();
 
@@ -2095,6 +2097,30 @@ void tst_QDataStream::stream_QByteArray2()
     }
 }
 
+void tst_QDataStream::stream_QJsonDocument()
+{
+    QByteArray buffer;
+    {
+        QDataStream save(&buffer, QIODevice::WriteOnly);
+        save << QByteArrayLiteral("invalidJson");
+        QDataStream load(&buffer, QIODevice::ReadOnly);
+        QJsonDocument doc;
+        load >> doc;
+        QVERIFY(doc.isEmpty());
+        QVERIFY(load.status() != QDataStream::Ok);
+        QCOMPARE(load.status(), QDataStream::ReadCorruptData);
+    }
+    {
+        QDataStream save(&buffer, QIODevice::WriteOnly);
+        QJsonDocument docSave(QJsonArray{1,2,3});
+        save << docSave;
+        QDataStream load(&buffer, QIODevice::ReadOnly);
+        QJsonDocument docLoad;
+        load >> docLoad;
+        QCOMPARE(docLoad, docSave);
+    }
+}
+
 void tst_QDataStream::setVersion_data()
 {
     QTest::addColumn<int>("vers");