Implement Different Signature Layouts

With the extended signature API, it is now possible to create
different layouts, depending on the usecase.

The "layout" module defines the layouts which we will need
and also implements the variable signature generation.

Task-number: PYSIDE-510
Task-number: PYSIDE-795
Change-Id: I5b9f88d9feb92cc4c8dc0e212860b6eb4fc16484
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

4 files changed, 246 insertions, 53 deletions

diff --git a/sources/pyside2/PySide2/CMakeLists.txt b/sources/pyside2/PySide2/CMakeLists.txt
index 0a76b6344..4709dd073 100644
--- a/sources/pyside2/PySide2/CMakeLists.txt
+++ b/sources/pyside2/PySide2/CMakeLists.txt
@@ -40,6 +40,8 @@ configure_file("${CMAKE_CURRENT_SOURCE_DIR}/support/__init__.py"
                "${CMAKE_CURRENT_BINARY_DIR}/support/__init__.py" COPYONLY)
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/support/signature/__init__.py"
                "${CMAKE_CURRENT_BINARY_DIR}/support/signature/__init__.py" COPYONLY)
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/support/signature/layout.py"
+               "${CMAKE_CURRENT_BINARY_DIR}/support/signature/layout.py" COPYONLY)
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/support/signature/loader.py"
                "${CMAKE_CURRENT_BINARY_DIR}/support/signature/loader.py" COPYONLY)
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/support/signature/mapping.py"
diff --git a/sources/pyside2/PySide2/support/signature/layout.py b/sources/pyside2/PySide2/support/signature/layout.py
new file mode 100644
index 000000000..ac7833f03
--- /dev/null
+++ b/sources/pyside2/PySide2/support/signature/layout.py
@@ -0,0 +1,237 @@
+#############################################################################
+##
+## 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
+
+"""
+layout.py
+
+The signature module now has the capability to configure
+differently formatted versions of signatures. The default
+layout is known from the "__signature__" attribute.
+
+The function "get_signature(ob, modifier=None)" produces the same
+signatures by default. By passing different modifiers, you
+can select different layouts.
+
+This module configures the different layouts which can be used.
+It also implements them in this file. The configurations are
+used literally as strings like "signature", "existence", etc.
+"""
+
+from textwrap import dedent
+from .loader import inspect
+
+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__
+
+class SignatureLayout(SimpleNamespace):
+    """
+    Configure a signature.
+
+    The layout of signatures can have different layouts which are
+    controlled by keyword arguments:
+
+    definition=True         Determines if self will generated.
+    defaults=True
+    ellipsis=False          Replaces defaults by "...".
+    return_annotation=True
+    parameter_names=True    False removes names before ":".
+    """
+    allowed_keys = SimpleNamespace(definition=True,
+                                   defaults=True,
+                                   ellipsis=False,
+                                   return_annotation=True,
+                                   parameter_names=True)
+    allowed_values = True, False
+
+    def __init__(self, **kwds):
+        args = SimpleNamespace(**self.allowed_keys.__dict__)
+        args.__dict__.update(kwds)
+        self.__dict__.update(args.__dict__)
+        err_keys = list(set(self.__dict__) - set(self.allowed_keys.__dict__))
+        if err_keys:
+            self._attributeerror(err_keys)
+        err_values = list(set(self.__dict__.values()) - set(self.allowed_values))
+        if err_values:
+            self._valueerror(err_values)
+
+    def __setattr__(self, key, value):
+        if key not in self.allowed_keys.__dict__:
+            self._attributeerror([key])
+        if value not in self.allowed_values:
+            self._valueerror([value])
+        self.__dict__[key] = value
+
+    def _attributeerror(self, err_keys):
+        err_keys = ", ".join(err_keys)
+        allowed_keys = ", ".join(self.allowed_keys.__dict__.keys())
+        raise AttributeError(dedent("""\
+            Not allowed: '{err_keys}'.
+            The only allowed keywords are '{allowed_keys}'.
+            """.format(**locals())))
+
+    def _valueerror(self, err_values):
+        err_values = ", ".join(map(str, err_values))
+        allowed_values = ", ".join(map(str, self.allowed_values))
+        raise ValueError(dedent("""\
+            Not allowed: '{err_values}'.
+            The only allowed values are '{allowed_values}'.
+            """.format(**locals())))
+
+# The following names are used literally in this module.
+# This way, we avoid the dict hashing problem.
+signature = SignatureLayout()
+
+existence = SignatureLayout(definition=False,
+                            defaults=False,
+                            return_annotation=False,
+                            parameter_names=False)
+
+hintingstub = SignatureLayout(ellipsis=True)
+
+typeerror = SignatureLayout(definition=False,
+                            return_annotation=False,
+                            parameter_names=False)
+
+def define_nameless_parameter():
+    """
+    Create Nameless Parameters
+
+    A nameless parameter has a reduced string representation.
+    This is done by cloning the parameter type and overwriting its
+    __str__ method. The inner structure is still a valid parameter.
+    """
+    def __str__(self):
+        # for Python 2, we must change self to be an instance of P
+        klass = self.__class__
+        self.__class__ = P
+        txt = P.__str__(self)
+        self.__class__ = klass
+        txt = txt[txt.index(":") + 1:].strip() if ":" in txt else txt
+        return txt
+
+    P = inspect.Parameter
+    newname = "NamelessParameter"
+    bases = P.__bases__
+    body = dict(P.__dict__) # get rid of mappingproxy
+    if "__slots__" in body:
+        # __slots__ would create duplicates
+        for name in body["__slots__"]:
+            del body[name]
+    body["__str__"] = __str__
+    return type(newname, bases, body)
+
+NamelessParameter = define_nameless_parameter()
+
+def make_signature_nameless(signature):
+    """
+    Make a Signature Nameless
+
+    We use an existing signature and change the type of its parameters.
+    The signature looks different, but is totally intact.
+    """
+    for key in signature.parameters.keys():
+        Signature.parameters[key].__class__ = NamelessParameter
+
+def create_signature(props, key):
+    if not props:
+        # empty signatures string
+        return
+    if isinstance(props["multi"], list):
+        # multi sig: call recursively
+        return list(create_signature(elem, key)
+                    for elem in props["multi"])
+    if type(key) is tuple:
+        sig_kind, modifier = key
+    else:
+        sig_kind, modifier = key, "signature"
+
+    layout = globals()[modifier]  # lookup of the modifier, here
+    if not isinstance(layout, SignatureLayout):
+        raise SystemError("Modifiers must be names of a SignatureLayout "
+                          "instance")
+
+    # this is the basic layout of a signature
+    varnames = props["varnames"]
+    if layout.definition:
+        if sig_kind == "method":
+            varnames = ("self",) + varnames
+        elif sig_kind == "staticmethod":
+            pass
+        elif sig_kind == "classmethod":
+            varnames = ("klass",) + varnames
+        else:
+            raise SystemError("Methods must be normal, staticmethod or "
+                              "classmethod")
+    # calculate the modifications
+    defaults = props["defaults"][:]
+    if not layout.defaults:
+        defaults = ()
+    if layout.ellipsis:
+        defaults = ("...",) * len(defaults)
+    annotations = props["annotations"].copy()
+    if not layout.return_annotation and "return" in annotations:
+        del annotations["return"]
+
+    # attach parameters to a fake function and build a signature
+    argstr = ", ".join(varnames)
+    fakefunc = eval("lambda {}: None".format(argstr))
+    fakefunc.__name__ = props["name"]
+    fakefunc.__defaults__ = defaults
+    fakefunc.__kwdefaults__ = props["kwdefaults"]
+    fakefunc.__annotations__ = annotations
+    sig = inspect._signature_from_function(inspect.Signature, fakefunc)
+
+    # the special case of nameless parameters
+    if not layout.parameter_names:
+        make_signature_nameless(sig)
+    return sig
+
+# end of file
diff --git a/sources/pyside2/PySide2/support/signature/lib/enum_sig.py b/sources/pyside2/PySide2/support/signature/lib/enum_sig.py
index ddc03c097..702ee7ebd 100644
--- a/sources/pyside2/PySide2/support/signature/lib/enum_sig.py
+++ b/sources/pyside2/PySide2/support/signature/lib/enum_sig.py
@@ -38,7 +38,7 @@
 #############################################################################
 
 import sys
-from PySide2.support.signature import inspect
+from PySide2.support.signature import inspect, get_signature
 
 
 class ExactEnumerator(object):
@@ -92,26 +92,6 @@ class ExactEnumerator(object):
         return ret
 
 
-def simplify(signature):
-    if isinstance(signature, list):
-        # remove duplicates which still sometimes occour:
-        ret = set(simplify(sig) for sig in signature)
-        return sorted(ret) if len(ret) > 1 else list(ret)[0]
-    ret = []
-    for pv in signature.parameters.values():
-        txt = str(pv)
-        if ":" not in txt:   # 'self' or '*args'
-            continue
-        txt = txt[txt.index(":") + 1:]
-        if "=" in txt:
-            txt = txt[:txt.index("=")]
-        quote = txt[0]
-        if quote in ("'", '"') and txt[-1] == quote:
-            txt = txt[1:-1]
-        ret.append(txt.strip())
-    return tuple(ret)
-
-
 class SimplifyingEnumerator(ExactEnumerator):
     """
     SimplifyingEnumerator enumerates all signatures in a module filtered.
@@ -126,9 +106,8 @@ class SimplifyingEnumerator(ExactEnumerator):
 
     def function(self, func_name, func):
         ret = self.result_type()
-        signature = getattr(func, '__signature__', None)
-        sig = simplify(signature) if signature is not None else None
-        if sig is not None and func_name not in ("next", "__next__"):
-            with self.fmt.function(func_name, sig) as key:
-                ret[key] = sig
+        signature = get_signature(func, 'existence')
+        if signature is not None and func_name not in ("next", "__next__"):
+            with self.fmt.function(func_name, signature) as key:
+                ret[key] = signature
         return ret
diff --git a/sources/pyside2/PySide2/support/signature/loader.py b/sources/pyside2/PySide2/support/signature/loader.py
index a055337bf..21ecebcc8 100644
--- a/sources/pyside2/PySide2/support/signature/loader.py
+++ b/sources/pyside2/PySide2/support/signature/loader.py
@@ -80,35 +80,10 @@ from PySide2.support.signature.parser import pyside_type_init
 sys.path.pop(0)
 # Note also that during the tests we have a different encoding that would
 # break the Python license decorated files without an encoding line.
+from PySide2.support.signature import layout
 
 # name used in signature.cpp
 def create_signature(props, key):
-    if not props:
-        # empty signatures string
-        return
-    if isinstance(props["multi"], list):
-        return list(create_signature(elem, key)
-                    for elem in props["multi"])
-    if type(key) is tuple:
-        sig_kind, modifier = key
-    else:
-        sig_kind, modifier = key, None
-    varnames = props["varnames"]
-    if sig_kind == "method":
-        varnames = ("self",) + varnames
-    elif sig_kind == "staticmethod":
-        pass
-    elif sig_kind == "classmethod":
-        varnames = ("klass",) + varnames
-    else:
-        raise SystemError("Methods must be normal, staticmethod or "
-                          "classmethod")
-    argstr = ", ".join(varnames)
-    fakefunc = eval("lambda {}: None".format(argstr))
-    fakefunc.__name__ = props["name"]
-    fakefunc.__defaults__ = props["defaults"]
-    fakefunc.__kwdefaults__ = props["kwdefaults"]
-    fakefunc.__annotations__ = props["annotations"]
-    return inspect._signature_from_function(inspect.Signature, fakefunc)
+    return layout.create_signature(props, key)
 
 # end of file