PySide6: Add QSharedMemory example

Task-number: PYSIDE-1370
Change-Id: Ica8cf855f59bed40b0d2c7ba5dfa1323871337bb
Reviewed-by: Christian Tismer <tismer@stackless.com>

7 files changed, 309 insertions, 0 deletions

diff --git a/examples/corelib/ipc/sharedmemory/dialog.py b/examples/corelib/ipc/sharedmemory/dialog.py
new file mode 100644
index 000000000..8045330e2
--- /dev/null
+++ b/examples/corelib/ipc/sharedmemory/dialog.py
@@ -0,0 +1,140 @@
+############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples 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."
+##
+## $QT_END_LICENSE$
+##
+############################################################################
+
+import os
+from pathlib import Path
+
+from PySide6.QtWidgets import QFileDialog, QDialog
+from PySide6.QtCore import QBuffer, QIODeviceBase, Slot, QSharedMemory, QDataStream, qVersion
+from PySide6.QtGui import QImage, QPixmap
+from ui_dialog import Ui_Dialog
+
+
+class Dialog(QDialog):
+    def __init__(self, parent=None):
+        super().__init__(parent)
+
+        v = qVersion()
+        name = f"QSharedMemoryExample_v{v}"
+        self._shared_memory = QSharedMemory(name)
+
+        self.ui = Ui_Dialog()
+        self.ui.setupUi(self)
+        self.ui.loadFromFileButton.clicked.connect(self.load_from_file)
+        self.ui.loadFromSharedMemoryButton.clicked.connect(self.load_from_memory)
+        self.setWindowTitle("SharedMemory Example")
+
+    def ensure_detached(self):
+        if self._shared_memory.isAttached():
+            self.detach()
+
+    def closeEvent(self, e):
+        self.ensure_detached()
+        e.accept()
+
+    @Slot()
+    def load_from_file(self):
+        self.ensure_detached()
+
+        self.ui.label.setText("Select an image file")
+        dir = Path(__file__).resolve().parent
+        fileName, _ = QFileDialog.getOpenFileName(self, "Choose Image",
+                                                  os.fspath(dir),
+                                                  "Images (*.png *.jpg)")
+        if not fileName:
+            return
+        image = QImage()
+        if not image.load(fileName):
+            self.ui.label.setText("Selected file is not an image, please select another.")
+            return
+        self.ui.label.setPixmap(QPixmap.fromImage(image))
+
+        # load into shared memory
+        buffer = QBuffer()
+        buffer.open(QIODeviceBase.WriteOnly)
+        out = QDataStream(buffer)
+        out << image
+        buffer.close()
+        size = buffer.size()
+
+        if not self._shared_memory.create(size):
+            self.ui.label.setText("Unable to create shared memory segment.")
+            return
+
+        self._shared_memory.lock()
+        _to = memoryview(self._shared_memory.data())
+        _from = buffer.data().data()
+        _to[0:size] = _from[0:size]
+        self._shared_memory.unlock()
+
+    @Slot()
+    def load_from_memory(self):
+        if not self._shared_memory.isAttached() and not self._shared_memory.attach():
+            self.ui.label.setText("Unable to attach to shared memory segment.\n"
+                                  "Load an image first.")
+            return
+
+        self._shared_memory.lock()
+        mv = memoryview(self._shared_memory.constData())
+        buffer = QBuffer()
+        buffer.setData(mv.tobytes())
+        buffer.open(QBuffer.ReadOnly)
+        _in = QDataStream(buffer)
+        image = QImage()
+        _in >> image
+        buffer.close()
+        self._shared_memory.unlock()
+        self._shared_memory.detach()
+
+        self.ui.label.setPixmap(QPixmap.fromImage(image))
+
+    def detach(self):
+        if not self._shared_memory.detach():
+            self.ui.label.setText(tr("Unable to detach from shared memory."))
diff --git a/examples/corelib/ipc/sharedmemory/dialog.ui b/examples/corelib/ipc/sharedmemory/dialog.ui
new file mode 100644
index 000000000..e99d6fb3c
--- /dev/null
+++ b/examples/corelib/ipc/sharedmemory/dialog.ui
@@ -0,0 +1,47 @@
+<ui version="4.0" >
+ <class>Dialog</class>
+ <widget class="QDialog" name="Dialog" >
+  <property name="geometry" >
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>451</width>
+    <height>322</height>
+   </rect>
+  </property>
+  <property name="windowTitle" >
+   <string>Dialog</string>
+  </property>
+  <layout class="QGridLayout" >
+   <item row="0" column="0" >
+    <widget class="QPushButton" name="loadFromFileButton" >
+     <property name="text" >
+      <string>Load Image From File...</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="0" >
+    <widget class="QLabel" name="label" >
+     <property name="text" >
+      <string>Launch two of these dialogs.  In the first, press the top button and load an image from a file.  In the second, press the bottom button and display the loaded image from shared memory.</string>
+     </property>
+     <property name="alignment" >
+      <set>Qt::AlignCenter</set>
+     </property>
+     <property name="wordWrap" >
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="0" >
+    <widget class="QPushButton" name="loadFromSharedMemoryButton" >
+     <property name="text" >
+      <string>Display Image From Shared Memory</string>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/examples/corelib/ipc/sharedmemory/image.png b/examples/corelib/ipc/sharedmemory/image.png
new file mode 100644
index 000000000..dd9345306
--- /dev/null
+++ b/examples/corelib/ipc/sharedmemory/image.png
diff --git a/examples/corelib/ipc/sharedmemory/main.py b/examples/corelib/ipc/sharedmemory/main.py
new file mode 100644
index 000000000..13e8f9dff
--- /dev/null
+++ b/examples/corelib/ipc/sharedmemory/main.py
@@ -0,0 +1,62 @@
+############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples 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."
+##
+## $QT_END_LICENSE$
+##
+############################################################################
+
+"""PySide6 port of the ipc/sharedmemory example from Qt v6.x"""
+
+import sys
+from PySide6.QtWidgets import QApplication
+from dialog import Dialog
+
+
+if __name__ == "__main__":
+    application = QApplication()
+    dialog = Dialog()
+    dialog.show()
+    sys.exit(application.exec())
diff --git a/examples/corelib/ipc/sharedmemory/qt.png b/examples/corelib/ipc/sharedmemory/qt.png
new file mode 100644
index 000000000..4f68e162d
--- /dev/null
+++ b/examples/corelib/ipc/sharedmemory/qt.png
diff --git a/examples/corelib/ipc/sharedmemory/sharedmemory.pyproject b/examples/corelib/ipc/sharedmemory/sharedmemory.pyproject
new file mode 100644
index 000000000..14fe88f13
--- /dev/null
+++ b/examples/corelib/ipc/sharedmemory/sharedmemory.pyproject
@@ -0,0 +1,3 @@
+{
+    "files": ["dialog.py", "dialog.ui", "image.png", "main.py", "qt.png"]
+}
diff --git a/examples/corelib/ipc/sharedmemory/ui_dialog.py b/examples/corelib/ipc/sharedmemory/ui_dialog.py
new file mode 100644
index 000000000..891c7b847
--- /dev/null
+++ b/examples/corelib/ipc/sharedmemory/ui_dialog.py
@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+
+################################################################################
+## Form generated from reading UI file 'dialog.ui'
+##
+## Created by: Qt User Interface Compiler version 6.2.0
+##
+## WARNING! All changes made in this file will be lost when recompiling UI file!
+################################################################################
+
+from PySide6.QtCore import (QCoreApplication, QDate, QDateTime, QLocale,
+    QMetaObject, QObject, QPoint, QRect,
+    QSize, QTime, QUrl, Qt)
+from PySide6.QtGui import (QBrush, QColor, QConicalGradient, QCursor,
+    QFont, QFontDatabase, QGradient, QIcon,
+    QImage, QKeySequence, QLinearGradient, QPainter,
+    QPalette, QPixmap, QRadialGradient, QTransform)
+from PySide6.QtWidgets import (QApplication, QDialog, QGridLayout, QLabel,
+    QPushButton, QSizePolicy)
+
+class Ui_Dialog(object):
+    def setupUi(self, Dialog):
+        if not Dialog.objectName():
+            Dialog.setObjectName(u"Dialog")
+        Dialog.resize(451, 322)
+        self.gridLayout = QGridLayout(Dialog)
+        self.gridLayout.setObjectName(u"gridLayout")
+        self.loadFromFileButton = QPushButton(Dialog)
+        self.loadFromFileButton.setObjectName(u"loadFromFileButton")
+
+        self.gridLayout.addWidget(self.loadFromFileButton, 0, 0, 1, 1)
+
+        self.label = QLabel(Dialog)
+        self.label.setObjectName(u"label")
+        self.label.setAlignment(Qt.AlignCenter)
+        self.label.setWordWrap(True)
+
+        self.gridLayout.addWidget(self.label, 1, 0, 1, 1)
+
+        self.loadFromSharedMemoryButton = QPushButton(Dialog)
+        self.loadFromSharedMemoryButton.setObjectName(u"loadFromSharedMemoryButton")
+
+        self.gridLayout.addWidget(self.loadFromSharedMemoryButton, 2, 0, 1, 1)
+
+
+        self.retranslateUi(Dialog)
+
+        QMetaObject.connectSlotsByName(Dialog)
+    # setupUi
+
+    def retranslateUi(self, Dialog):
+        Dialog.setWindowTitle(QCoreApplication.translate("Dialog", u"Dialog", None))
+        self.loadFromFileButton.setText(QCoreApplication.translate("Dialog", u"Load Image From File...", None))
+        self.label.setText(QCoreApplication.translate("Dialog", u"Launch two of these dialogs.  In the first, press the top button and load an image from a file.  In the second, press the bottom button and display the loaded image from shared memory.", None))
+        self.loadFromSharedMemoryButton.setText(QCoreApplication.translate("Dialog", u"Display Image From Shared Memory", None))
+    # retranslateUi
+