PySide6: Add QSharedMemory

Return a buffer from data()/constData(), from which a memoryview can
be constructed.

[ChangeLog][PySide6] QSharedMemory was added.

Fixes: PYSIDE-1370
Task-number: PYSIDE-1482
Change-Id: I089801c55ed696d3dd59ef64da0e52e538e9b54d
Reviewed-by: Christian Tismer <tismer@stackless.com>
(cherry picked from commit 4ee3c492e3fd19d7f863f0e2853901e0cb8f2c9e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

5 files changed, 185 insertions, 1 deletions

diff --git a/sources/pyside6/PySide6/QtCore/CMakeLists.txt b/sources/pyside6/PySide6/QtCore/CMakeLists.txt
index a6d523e89..66b15b060 100644
--- a/sources/pyside6/PySide6/QtCore/CMakeLists.txt
+++ b/sources/pyside6/PySide6/QtCore/CMakeLists.txt
@@ -128,6 +128,7 @@ ${QtCore_GEN_DIR}/qsemaphore_wrapper.cpp
 ${QtCore_GEN_DIR}/qsemaphorereleaser_wrapper.cpp
 ${QtCore_GEN_DIR}/qsequentialanimationgroup_wrapper.cpp
 ${QtCore_GEN_DIR}/qsettings_wrapper.cpp
+${QtCore_GEN_DIR}/qsharedmemory_wrapper.cpp
 ${QtCore_GEN_DIR}/qsignalblocker_wrapper.cpp
 ${QtCore_GEN_DIR}/qsignalmapper_wrapper.cpp
 ${QtCore_GEN_DIR}/qsize_wrapper.cpp
diff --git a/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml b/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml
index bec575e54..16d739056 100644
--- a/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml
+++ b/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml
@@ -513,7 +513,7 @@
 
   <rejection class="*" function-name="d_func"/>
   <rejection class="*" function-name="data_ptr"/>
-  <rejection class="*" function-name="detach"/>
+  <rejection class="^(?!QSharedMemory).*$" function-name="detach"/>
   <rejection class="*" function-name="isDetached"/>
   <rejection class="*" field-name="d_ptr"/>
   <rejection class="*" field-name="d"/>
@@ -3020,6 +3020,20 @@
   <object-type name="QPluginLoader"/>
   <object-type name="QStringListModel"/>
 
+   <object-type name="QSharedMemory">
+       <enum-type name="AccessMode"/>
+       <enum-type name="SharedMemoryError"/>
+       <modify-function signature="data()">
+         <inject-code class="target" position="end"
+                      file="../glue/qtcore.cpp" snippet="qsharedmemory_data_readwrite"/>
+       </modify-function>
+       <modify-function signature="constData()const">
+         <inject-code class="target" position="end"
+                      file="../glue/qtcore.cpp" snippet="qsharedmemory_data_readonly"/>
+       </modify-function>
+       <modify-function signature="data()const" remove="all"/>
+   </object-type>
+
   <object-type name="QStringConverterBase">
     <enum-type name="Flag" flags="Flags"/>
     <object-type name="State"/>
diff --git a/sources/pyside6/PySide6/glue/qtcore.cpp b/sources/pyside6/PySide6/glue/qtcore.cpp
index a30c6635b..bbc18c59e 100644
--- a/sources/pyside6/PySide6/glue/qtcore.cpp
+++ b/sources/pyside6/PySide6/glue/qtcore.cpp
@@ -1913,3 +1913,13 @@ Py_DECREF(oldResult);
 Py_DECREF(suffix);
 #endif
 // @snippet qlibraryinfo_build
+
+// @snippet qsharedmemory_data_readonly
+%PYARG_0 = Shiboken::Buffer::newObject(%CPPSELF.%FUNCTION_NAME(), %CPPSELF.size());
+// @snippet qsharedmemory_data_readonly
+
+// @snippet qsharedmemory_data_readwrite
+// FIXME: There is no way to tell whether QSharedMemory was attached read/write
+%PYARG_0 = Shiboken::Buffer::newObject(%CPPSELF.%FUNCTION_NAME(), %CPPSELF.size(),
+                                       Shiboken::Buffer::ReadWrite);
+// @snippet qsharedmemory_data_readwrite
diff --git a/sources/pyside6/tests/QtCore/qsharedmemory_client.py b/sources/pyside6/tests/QtCore/qsharedmemory_client.py
new file mode 100644
index 000000000..fd994b0cb
--- /dev/null
+++ b/sources/pyside6/tests/QtCore/qsharedmemory_client.py
@@ -0,0 +1,61 @@
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of the test suite of Qt for Python.
+##
+## $QT_BEGIN_LICENSE:GPL-EXCEPT$
+## 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 General Public License Usage
+## Alternatively, this file may be used under the terms of the GNU
+## General Public License version 3 as published by the Free Software
+## Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+## 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-3.0.html.
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+'''Client for the unit test of QSharedMemory'''
+
+import sys
+
+from PySide6.QtCore import QSharedMemory
+
+
+def read_string(shared_memory):
+    """Read out a null-terminated string from the QSharedMemory"""
+    mv = memoryview(shared_memory.constData())
+    result = ''
+    for i in range(shared_memory.size()):
+        char = mv[i]
+        if not char:
+            break
+        result += chr(char)
+    return result
+
+
+if __name__ == '__main__':
+    if len(sys.argv) != 2:
+        print('Pass segment name', file=sys.stderr)
+        sys.exit(-1)
+    shared_memory = QSharedMemory(sys.argv[1])
+    if not shared_memory.attach(QSharedMemory.ReadOnly):
+        raise SystemError(f'attach to "{name}" failed')
+    if not shared_memory.lock():
+        raise SystemError(f'lock of "{name}" failed')
+    data = read_string(shared_memory)
+    shared_memory.unlock()
+    shared_memory.detach()
+    sys.stdout.write(data)
+    sys.exit(0)
diff --git a/sources/pyside6/tests/QtCore/qsharedmemory_test.py b/sources/pyside6/tests/QtCore/qsharedmemory_test.py
new file mode 100644
index 000000000..ee2e6c40a
--- /dev/null
+++ b/sources/pyside6/tests/QtCore/qsharedmemory_test.py
@@ -0,0 +1,98 @@
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of the test suite of Qt for Python.
+##
+## $QT_BEGIN_LICENSE:GPL-EXCEPT$
+## 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 General Public License Usage
+## Alternatively, this file may be used under the terms of the GNU
+## General Public License version 3 as published by the Free Software
+## Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+## 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-3.0.html.
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+'''Unit tests for QSharedMemory'''
+
+import ctypes
+import os
+import subprocess
+import sys
+import unittest
+
+from pathlib import Path
+FILE = Path(__file__).resolve()
+sys.path.append(os.fspath(FILE.parents[1]))
+from init_paths import init_test_paths
+init_test_paths(False)
+
+from PySide6.QtCore import QSharedMemory, QRandomGenerator, qVersion
+from qsharedmemory_client import read_string
+
+
+TEST_STRING = 'ABCD'
+
+
+def run(cmd):
+    # FIXME Python 3.7: Use subprocess.run()
+    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, shell=False,
+                            universal_newlines=True)
+    output, error = proc.communicate()
+    proc.wait()
+    return_code = proc.returncode
+    return (return_code, output, error)
+
+
+class QSharedMemoryTest(unittest.TestCase):
+
+    def setUp(self):
+        r = QRandomGenerator.global_().bounded(1000)
+        v = qVersion()
+        self._name = f"pyside{v}_test_{r}"
+        print(self._name)
+        self._shared_memory = QSharedMemory(self._name)
+
+    def tearDown(self):
+        if self._shared_memory.isAttached():
+            self._shared_memory.detach()
+
+    def test(self):
+        # Create and write
+        self.assertTrue(self._shared_memory.create(1024, QSharedMemory.ReadWrite))
+        self.assertTrue(self._shared_memory.lock())
+        mv = memoryview(self._shared_memory.data())
+        for idx, c in enumerate(TEST_STRING + chr(0)):
+            mv[idx] = ord(c)
+        mv = None
+        self.assertTrue(self._shared_memory.unlock())
+
+        # Read
+        self.assertTrue(self._shared_memory.lock())
+        self.assertEqual(read_string(self._shared_memory), TEST_STRING)
+        self.assertTrue(self._shared_memory.unlock())
+
+        # Run a subprocess and let it read
+        client = FILE.parent / 'qsharedmemory_client.py'
+        returncode, output, error = run([sys.executable, client, self._name])
+        if error:
+            print(error, file=sys.stderr)
+        self.assertEqual(returncode, 0)
+        self.assertEqual(output, TEST_STRING)
+
+
+if __name__ == '__main__':
+    unittest.main()