1 files changed, 34 insertions, 58 deletions

diff --git a/src/gui/painting/qpainter_p.h b/src/gui/painting/qpainter_p.h
index 71e90c9717..0ddd78fb2a 100644
--- a/src/gui/painting/qpainter_p.h
+++ b/src/gui/painting/qpainter_p.h
@@ -1,41 +1,5 @@
-/****************************************************************************
-**
-** Copyright (C) 2016 The Qt Company Ltd.
-** Contact: https://www.qt.io/licensing/
-**
-** This file is part of the QtGui module of the Qt Toolkit.
-**
-** $QT_BEGIN_LICENSE:LGPL$
-** 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.
-**
-** GNU Lesser General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU Lesser
-** General Public License version 3 as published by the Free Software
-** Foundation and appearing in the file LICENSE.LGPL3 included in the
-** packaging of this file. Please review the following information to
-** ensure the GNU Lesser General Public License version 3 requirements
-** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
-**
-** GNU General Public License Usage
-** Alternatively, this file may be used under the terms of the GNU
-** General Public License version 2.0 or (at your option) the GNU General
-** Public license version 3 or any later version approved by the KDE Free
-** Qt Foundation. The licenses are as published by the Free Software
-** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
-** included in the packaging of this file. Please review the following
-** information to ensure the GNU General Public License requirements will
-** be met: https://www.gnu.org/licenses/gpl-2.0.html and
-** https://www.gnu.org/licenses/gpl-3.0.html.
-**
-** $QT_END_LICENSE$
-**
-****************************************************************************/
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #ifndef QPAINTER_P_H
 #define QPAINTER_P_H
@@ -66,6 +30,7 @@
 #include <private/qpen_p.h>
 
 #include <memory>
+#include <stack>
 
 QT_BEGIN_NAMESPACE
 
@@ -193,28 +158,29 @@ class QPainterPrivate
 {
     Q_DECLARE_PUBLIC(QPainter)
 public:
-    QPainterPrivate(QPainter *painter)
-    : q_ptr(painter), d_ptrs(nullptr), state(nullptr), dummyState(nullptr), txinv(0), inDestructor(false), d_ptrs_size(0),
-        refcount(1), device(nullptr), original_device(nullptr), helper_device(nullptr), engine(nullptr), emulationEngine(nullptr),
-        extended(nullptr)
-    {
-    }
-
+    explicit QPainterPrivate(QPainter *painter);
     ~QPainterPrivate();
 
     QPainter *q_ptr;
-    QPainterPrivate **d_ptrs;
-
-    QPainterState *state;
-    QVarLengthArray<QPainterState *, 8> states;
+    // Allocate space for 4 d-pointers (enough for up to 4 sub-sequent
+    // redirections within the same paintEvent(), which should be enough
+    // in 99% of all cases). E.g: A renders B which renders C which renders D.
+    static constexpr qsizetype NDPtrs = 4;
+    QVarLengthArray<QPainterPrivate*, NDPtrs> d_ptrs;
+
+    std::unique_ptr<QPainterState> state;
+    template <typename T, std::size_t N = 8>
+    struct SmallStack : std::stack<T, QVarLengthArray<T, N>> {
+        void clear() { this->c.clear(); }
+    };
+    SmallStack<std::unique_ptr<QPainterState>> savedStates;
 
     mutable std::unique_ptr<QPainterDummyState> dummyState;
 
     QTransform invMatrix;
     uint txinv:1;
     uint inDestructor : 1;
-    uint d_ptrs_size;
-    uint refcount;
+    uint refcount = 1;
 
     enum DrawOperation { StrokeDraw        = 0x1,
                          FillDraw          = 0x2,
@@ -230,6 +196,7 @@ public:
     void updateEmulationSpecifier(QPainterState *s);
     void updateStateImpl(QPainterState *state);
     void updateState(QPainterState *state);
+    void updateState(std::unique_ptr<QPainterState> &state) { updateState(state.get()); }
 
     void draw_helper(const QPainterPath &path, DrawOperation operation = StrokeAndFillDraw);
     void drawStretchedGradient(const QPainterPath &path, DrawOperation operation);
@@ -249,7 +216,7 @@ public:
 
     static QPainterPrivate *get(QPainter *painter)
     {
-        return painter->d_ptr.data();
+        return painter->d_ptr.get();
     }
 
     QTransform viewTransform() const;
@@ -259,12 +226,21 @@ public:
     void detachPainterPrivate(QPainter *q);
     void initFrom(const QPaintDevice *device);
 
-    QPaintDevice *device;
-    QPaintDevice *original_device;
-    QPaintDevice *helper_device;
-    QPaintEngine *engine;
-    QEmulationPaintEngine *emulationEngine;
-    QPaintEngineEx *extended;
+    QPaintDevice *device = nullptr;
+    QPaintDevice *original_device = nullptr;
+    QPaintDevice *helper_device = nullptr;
+
+    struct QPaintEngineDestructor {
+        void operator()(QPaintEngine *pe) const noexcept
+        {
+            if (pe && pe->autoDestruct())
+                delete pe;
+        }
+    };
+    std::unique_ptr<QPaintEngine, QPaintEngineDestructor> engine;
+
+    std::unique_ptr<QEmulationPaintEngine> emulationEngine;
+    QPaintEngineEx *extended = nullptr;
     QBrush colorBrush;          // for fill with solid color
 };