Cleanup signature module before substantial change

There were some refinements applied while developing
"Support Pointer Primitive Types by Arrays or Result Tuples".
This patch moves these changes out which are not essential
for that patch. They include

- sort all mapping groups by name
- replace huge regex by a pattern generator
- replace dictionary string entries by SimpleNameSpace
- improve PEP 563 handling
- simplify "zero(sometype)" substantially
- better handling of "QGenericMatrix" (preview)

A test for the generated pattern against a reference parser
was added.

Task-number: PYSIDE-795
Task-number: PYSIDE-951
Change-Id: I5a6b236850c63a7db77b7f7b88881486fd1e61be
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

1 files changed, 135 insertions, 0 deletions

diff --git a/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/lib/tool.py b/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/lib/tool.py
new file mode 100644
index 000000000..b34bfb404
--- /dev/null
+++ b/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/lib/tool.py
@@ -0,0 +1,135 @@
+#############################################################################
+##
+## Copyright (C) 2019 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
+
+"""
+tool.py
+
+Some useful stuff, see below.
+"""
+
+from textwrap import dedent
+
+
+class SimpleNamespace(object):
+    # From types.rst, because the builtin is implemented in Python 3, only.
+    def __init__(self, **kwargs):
+        self.__dict__.update(kwargs)
+
+    def __repr__(self):
+        keys = sorted(self.__dict__)
+        items = ("{}={!r}".format(k, self.__dict__[k]) for k in keys)
+        return "{}({})".format(type(self).__name__, ", ".join(items))
+
+    def __eq__(self, other):
+        return self.__dict__ == other.__dict__
+
+try:
+    from types import SimpleNamespace
+except ImportError:
+    pass
+
+
+def build_brace_pattern(level, separators=""):
+    """
+    Build a brace pattern upto a given depth
+
+    The brace pattern parses any pattern with round, square, curly, or angle
+    brackets. Inside those brackets, any characters are allowed.
+
+    The structure is quite simple and is recursively repeated as needed.
+    When separators are given, the match stops at that separator.
+
+    Reason to use this instead of some Python function:
+    The resulting regex is _very_ fast!
+
+    A faster replacement would be written in C, but this solution is
+    sufficient when the nesting level is not too large.
+
+    Because of the recursive nature of the pattern, the size grows by a factor
+    of 4 at every level, as does the creation time. Up to a level of 6, this
+    is below 10 ms.
+
+    There are other regex engines available which allow recursive patterns,
+    avoiding this problem completely. It might be considered to switch to
+    such an engine if the external module is not a problem.
+    """
+    def escape(str):
+        return "".join("\\" + c for c in str)
+
+    ro, rc = round  = "()"
+    so, sc = square = "[]"
+    co, cc = curly  = "CD"      # we insert "{}", later...
+    ao, ac = angle  = "<>"
+    qu, bs = '"', "\\"
+    all = round + square + curly + angle
+    __ = "  "
+    ro, rc, so, sc, co, cc, ao, ac, separators, qu, bs, all = map(
+        escape, (ro, rc, so, sc, co, cc, ao, ac, separators, qu, bs, all))
+
+    no_brace_sep_q = r"[^{all}{separators}{qu}{bs}]".format(**locals())
+    no_quote = r"(?: [^{qu}{bs}] | {bs}. )*".format(**locals())
+    pattern = dedent(r"""
+        (
+          (?: {__} {no_brace_sep_q}
+            | {qu} {no_quote} {qu}
+            | {ro} {replacer} {rc}
+            | {so} {replacer} {sc}
+            | {co} {replacer} {cc}
+            | {ao} {replacer} {ac}
+          )*
+        )
+        """)
+    no_braces_q = "[^{all}{qu}{bs}]*".format(**locals())
+    repeated = dedent(r"""
+        {indent}  (?: {__} {no_braces_q}
+        {indent}    | {qu} {no_quote} {qu}
+        {indent}    | {ro} {replacer} {rc}
+        {indent}    | {so} {replacer} {sc}
+        {indent}    | {co} {replacer} {cc}
+        {indent}    | {ao} {replacer} {ac}
+        {indent}  )*
+        """)
+    for idx in range(level):
+        pattern = pattern.format(replacer = repeated if idx < level-1 else no_braces_q,
+                                 indent = idx * "    ", **locals())
+    return pattern.replace("C", "{").replace("D", "}")
+
+# eof