Split The Signature Module After The Project Split

The PySide project has been split into three pieces, including
Shiboken. This had far-reaching consequences for the signature project.

Shiboken can be run together with PySide or alone,
with tests or without. In every configuration, the signature
module has to work correctly.

During tests, the shiboken binary also hides the shiboken module,
and we had to use extra efforts to always guarantee the accessibility
of all signature modules.

This commit is the preparation for typeerrors implemented with the
signature module. It has been split off because the splitting
is not directly related, besides these unawaited consequences.

I re-added and corrected voidptr_test and simplified the calls.
Remark.. We should rename shiboken to Shiboken in all imports.

I also simplified initialization. After "from PySide2 import QtCore",
now a simple access like "type.__signature__" triggers initialization.

Further, I removed all traces of "signature_loader" and allowed
loading everything from PySide2.support.signature, again. The
loader is now needed internally, only.

Also, moved the type patching into FinishSignatureInitialization
to support modules with no classes at all.

The "testbinding" problem was finally identified as a name clash
when the same function is also a signal. A further investigation
showed that there exists also a regular PySide method with
that problem. The test was extended to all methods, and it
maps now all these cases to "{name}.overload".

Updated the included typing27.py from https://pypi.org/project/typing/
from version 3.6.2 to version 3.6.6 .

Task-number: PYSIDE-749
Change-Id: Ie33b8c6b0df5640212f8991539088593a041a05c
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

1 files changed, 176 insertions, 0 deletions

diff --git a/sources/shiboken2/shibokenmodule/support/signature/loader.py b/sources/shiboken2/shibokenmodule/support/signature/loader.py
new file mode 100644
index 000000000..83493e511
--- /dev/null
+++ b/sources/shiboken2/shibokenmodule/support/signature/loader.py
@@ -0,0 +1,176 @@
+#############################################################################
+##
+## Copyright (C) 2018 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of Qt for Python.
+##
+## $QT_BEGIN_LICENSE:LGPL$
+## 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.
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+from __future__ import print_function, absolute_import
+
+"""
+loader.py
+
+The loader has to lazy-load the signature module and also provides a few
+Python modules to support Python 2.7 .
+
+This file was originally directly embedded into the C source.
+After it grew more and more, I now prefer to have it as Python file.
+The remaining stub loader in the C source is now only a short string.
+
+This version does no longer use an embedded .zip file but is a package.
+The old code without a package but with zip compression can still be found
+at https://codereview.qt-project.org/#/c/203533/ for reference.
+"""
+
+import sys
+import os
+import traceback
+import types
+from contextlib import contextmanager
+from distutils.sysconfig import get_python_lib
+
+"""
+A note on the import problem (solved):
+
+During the tests, the shiboken build structure has the layout
+
+    shiboken2/shibokenmodule/shiboken2.abi3.so
+
+and the name "shiboken2" in sys.modules points directly to the binary
+file, hiding the outer shiboken2 module.
+
+To fix that, we temporarily remove the binary from sys.path,
+do the needed imports and then restore the binary.
+This action was put into a context manager for readability.
+"""
+
+# On Python 2, we only have ImportError, which is way too coarse.
+# When problems occour, please use Python 3, because it has the finer
+# ModuleNotFoundError.
+
+try:
+    ModuleNotFoundError
+except NameError:
+    ModuleNotFoundError = ImportError
+
+@contextmanager
+def ensure_import_support():
+    # Make sure that we always have the shiboken containing package first.
+    # This is sometimes hidden by the ctest paths.
+    # We adjust the path in a way that the support folder comes first.
+    # This can be in "shiboken2/support" or in "shibokenmodule/support",
+    # so we use the "support" folder as toplevel.
+    sbk_support_dir = os.path.abspath(os.path.join(__file__, "..", "..", ".."))
+    sys.path.insert(0, sbk_support_dir)
+    sbk = "shiboken2"
+    save_sbk = sys.modules.pop(sbk) if sbk in sys.modules else None
+    # make sure that we get at the support folder
+    try:
+        import support
+        yield
+    except Exception as e:
+        print("Problem importing support:")
+        print(e)
+        traceback.print_exc()
+        sys.stdout.flush()
+        sys.exit(-1)
+    if save_sbk:
+        sys.modules[sbk] = save_sbk
+    sys.path.pop(0)
+
+
+with ensure_import_support():
+    # We store all needed modules in signature_loader.
+    # This way, they are always accessible.
+    import signature_loader
+
+    if sys.version_info >= (3,):
+        import typing
+        import inspect
+    else:
+        import inspect
+        namespace = inspect.__dict__
+        from support.signature import typing
+        from support.signature import backport_inspect as inspect
+        _doc = inspect.__doc__
+        inspect.__dict__.update(namespace)
+        inspect.__doc__ += _doc
+        # force inspect to find all attributes. See "heuristic" in pydoc.py!
+        inspect.__all__ = list(x for x in dir(inspect) if not x.startswith("_"))
+
+    def put_into_loader_package(module, loader=signature_loader):
+        # Note: the "with" statement hides that we are no longer in a
+        # global context, but inside ensure_import_support. Therefore,
+        # we need to explicitly pass the signature_loader in.
+
+        # take the last component of the module name
+        name = module.__name__.rsplit(".", 1)[-1]
+        # allow access as signature_loader.typing
+        setattr(loader, name, module)
+        # put into sys.modules as a package to allow all import options
+        fullname = "{}.{}".format(loader.__name__, name)
+        sys.modules[fullname] = module
+
+    put_into_loader_package(typing)
+    put_into_loader_package(inspect)
+    from support.signature import mapping as sbk_mapping
+    sbk_mapping.__name__ = "sbk_mapping"
+    put_into_loader_package(sbk_mapping)
+    # We may or may not use PySide.
+    try:
+        from PySide2.support.signature import mapping
+    except ModuleNotFoundError:
+        mapping = sbk_mapping
+        mapping.__name__ = "mapping"
+    put_into_loader_package(mapping)
+    from support.signature import layout
+    put_into_loader_package(layout)
+    from support.signature.lib import enum_sig
+    put_into_loader_package(enum_sig)
+    from support.signature.parser import pyside_type_init
+
+
+# Note also that during the tests we have a different encoding that would
+# break the Python license decorated files without an encoding line.
+
+# name used in signature.cpp
+def create_signature(props, key):
+    return layout.create_signature(props, key)
+
+# name used in signature.cpp
+def seterror_argument(args, func_name):
+    return errorhandler.seterror_argument(args, func_name)
+
+# end of file