Doc: Fix occurrences of \Q_OBJECT in code snippets

'Q_OBJECT', even in a comment, interferes with automoc.
Prefixing it with a backslash solves the automoc issue,
but documentation looks wrong as content inside \code
is taken verbatim.

Move code snippets to doc/snippets and refer to them
with \snippet commands.

Change-Id: Ied7fdf87ef5edd2b237498b91b162c19bf7bc636
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
(cherry picked from commit ed6f55ca126c80514e886b3b400a22ba5d443589)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

6 files changed, 260 insertions, 73 deletions

diff --git a/src/qml/doc/snippets/code/src_qml_qqmlengine.cpp b/src/qml/doc/snippets/code/src_qml_qqmlengine.cpp
new file mode 100644
index 0000000000..228275e120
--- /dev/null
+++ b/src/qml/doc/snippets/code/src_qml_qqmlengine.cpp
@@ -0,0 +1,91 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//! [0]
+class MySingleton : public QObject {
+    Q_OBJECT
+
+    // Register as default constructed singleton.
+    QML_ELEMENT
+    QML_SINGLETON
+
+    static int typeId;
+    // ...
+};
+//! [0]
+
+/*
+//! [1]
+    MySingleton::typeId = qmlTypeId(...);
+//! [1]
+*/
+
+void wrapper2() {
+//! [2]
+    // Retrieve as QObject*
+    QQmlEngine engine;
+    MySingleton* instance = engine.singletonInstance<MySingleton*>(MySingleton::typeId);
+//! [2]
+}
+
+/*
+//! [3]
+    // Register with QJSValue callback
+    int typeId = qmlRegisterSingletonType(...);
+//! [3]
+*/
+
+void wrapper4(int typeId) {
+//! [4]
+    // Retrieve as QJSValue
+    QQmlEngine engine;
+    QJSValue instance = engine.singletonInstance<QJSValue>(typeId);
+//! [4]
+}
diff --git a/src/qml/doc/snippets/code/src_qml_qqmllist.cpp b/src/qml/doc/snippets/code/src_qml_qqmllist.cpp
new file mode 100644
index 0000000000..7fd6664dd7
--- /dev/null
+++ b/src/qml/doc/snippets/code/src_qml_qqmllist.cpp
@@ -0,0 +1,94 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+namespace DocWrapper0 {
+//! [0]
+class FruitBasket : QObject {
+    Q_OBJECT
+    QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND
+    Q_PROPERTY(QQmlListProperty<Fruit> fruit READ fruit)
+
+    public:
+    // ...
+    QQmlListProperty<Fruit> fruit();
+    // ...
+};
+//! [0]
+}
+
+namespace DocWrapper1 {
+//! [1]
+class FruitBasket : QObject {
+    Q_OBJECT
+    QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT
+    Q_PROPERTY(QQmlListProperty<Fruit> fruit READ fruit)
+
+    public:
+    // ...
+    QQmlListProperty<Fruit> fruit();
+    // ...
+};
+//! [1]
+}
+
+namespace DocWrapper2 {
+//! [2]
+class FruitBasket : QObject {
+    Q_OBJECT
+    QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE
+    Q_PROPERTY(QQmlListProperty<Fruit> fruit READ fruit)
+
+    public:
+    // ...
+    QQmlListProperty<Fruit> fruit();
+    // ...
+};
+//! [2]
+}
diff --git a/src/qml/doc/snippets/code/src_qml_qqmlparserstatus.cpp b/src/qml/doc/snippets/code/src_qml_qqmlparserstatus.cpp
new file mode 100644
index 0000000000..259ea15b3f
--- /dev/null
+++ b/src/qml/doc/snippets/code/src_qml_qqmlparserstatus.cpp
@@ -0,0 +1,63 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//! [0]
+class MyObject : public QObject, public QQmlParserStatus
+{
+    Q_OBJECT
+    Q_INTERFACES(QQmlParserStatus)
+
+public:
+    MyObject(QObject *parent = 0);
+    // ...
+    void classBegin();
+    void componentComplete();
+};
+//! [0]
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 0b6b456473..0208b99621 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -1368,34 +1368,18 @@ void QQmlEngine::captureProperty(QObject *object, const QMetaProperty &property)
   type, either a default constructed QJSValue or a \c nullptr is returned.
 
   QObject* example:
-  \code
-  class MySingleton : public QObject {
-    \Q_OBJECT
-
-    // Register as default constructed singleton.
-    QML_ELEMENT
-    QML_SINGLETON
-
-    static int typeId;
-    // ...
-  };
 
-  MySingleton::typeId = qmlTypeId(...);
-
-  // Retrieve as QObject*
-  QQmlEngine engine;
-  MySingleton* instance = engine.singletonInstance<MySingleton*>(MySingleton::typeId);
-  \endcode
+  \snippet code/src_qml_qqmlengine.cpp 0
+  \codeline
+  \snippet code/src_qml_qqmlengine.cpp 1
+  \codeline
+  \snippet code/src_qml_qqmlengine.cpp 2
 
   QJSValue example:
-  \code
-  // Register with QJSValue callback
-  int typeId = qmlRegisterSingletonType(...);
 
-  // Retrieve as QJSValue
-  QQmlEngine engine;
-  QJSValue instance = engine.singletonInstance<QJSValue>(typeId);
-  \endcode
+  \snippet code/src_qml_qqmlengine.cpp 3
+  \codeline
+  \snippet code/src_qml_qqmlengine.cpp 4
 
   It is recommended to store the QML type id, e.g. as a static member in the
   singleton class. The lookup via qmlTypeId() is costly.
diff --git a/src/qml/qml/qqmllist.cpp b/src/qml/qml/qqmllist.cpp
index 51499f816d..a3380a6c22 100644
--- a/src/qml/qml/qqmllist.cpp
+++ b/src/qml/qml/qqmllist.cpp
@@ -436,18 +436,7 @@ QML list properties are type-safe - in this case \c {Fruit} is a QObject type th
     When assigning the property in a derived type, the values are appended
     to those of the base class. This is the default behavior.
 
-    \code
-    class FruitBasket : QObject {
-        \Q_OBJECT
-        QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND
-        Q_PROPERTY(QQmlListProperty<Fruit> fruit READ fruit)
-
-        public:
-        // ...
-        QQmlListProperty<Fruit> fruit();
-        // ...
-    };
-    \endcode
+    \snippet code/src_qml_qqmllist.cpp 0
 
     \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT
     \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE
@@ -463,18 +452,7 @@ QML list properties are type-safe - in this case \c {Fruit} is a QObject type th
     the base class unless it's the default property.
     In the case of the default property, values are appended to those of the base class.
 
-    \code
-    class FruitBasket : QObject {
-        \Q_OBJECT
-        QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT
-        Q_PROPERTY(QQmlListProperty<Fruit> fruit READ fruit)
-
-        public:
-        // ...
-        QQmlListProperty<Fruit> fruit();
-        // ...
-    };
-    \endcode
+    \snippet code/src_qml_qqmllist.cpp 1
 
     \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND
     \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE
@@ -488,18 +466,7 @@ QML list properties are type-safe - in this case \c {Fruit} is a QObject type th
     When assigning the property in a derived type, the values replace those
     of the base class.
 
-    \code
-    class FruitBasket : QObject {
-        \Q_OBJECT
-        QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE
-        Q_PROPERTY(QQmlListProperty<Fruit> fruit READ fruit)
-
-        public:
-        // ...
-        QQmlListProperty<Fruit> fruit();
-        // ...
-    };
-    \endcode
+    \snippet code/src_qml_qqmllist.cpp 2
 
     \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND
     \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT
diff --git a/src/qml/qml/qqmlparserstatus.cpp b/src/qml/qml/qqmlparserstatus.cpp
index cd45e6668b..d2aa679a95 100644
--- a/src/qml/qml/qqmlparserstatus.cpp
+++ b/src/qml/qml/qqmlparserstatus.cpp
@@ -68,19 +68,7 @@ QT_BEGIN_NAMESPACE
     To use QQmlParserStatus, you must inherit both a QObject-derived class
     and QQmlParserStatus, and use the Q_INTERFACES() macro.
 
-    \code
-    class MyObject : public QObject, public QQmlParserStatus
-    {
-        \Q_OBJECT
-        Q_INTERFACES(QQmlParserStatus)
-
-    public:
-        MyObject(QObject *parent = 0);
-        ...
-        void classBegin();
-        void componentComplete();
-    }
-    \endcode
+    \snippet code/src_qml_qqmlparserstatus.cpp 0
 */
 
 /*! \internal */