Add QtCore.Slot.__signature__ and much more manually

The signature of QtCore.Slot and other classes could not automatically
be generated because the function is not generated by cppgenerator.cpp .
We add it manually in the C++ code into the generation process.

The case of QtCore.Slot had diverse follow-up issues to be solved:

- Classes which did not inherit from Shiboken were not generated.
  This is a long-standing omission and creates very many new
  simple types.

- The arity of Slot has default arguments after the varargs parameter
  "*types". This needed an extended Python parser analysis that fixes
  the arguments given to the inspect module, accordingly.

- The signature generation was completely new implemented and
  relies no longer on the restricted syntax of a Python (2) function
  but generates signatures directly as Parameter instances.

Implemented classes with hand-made signatures:

    QtCore.ClassInfo
    QtCore.MetaFunction,
    QtCore.MetaSignal
    QtCore.Property
    QtCore.Signal
    QtCore.SignalInstance
    QtCore.Slot
    QtQml.ListProperty
    QtQml.VolatileBool

As a side effect, many more subtypes were published.
Enums are done, which concludes this work.

Fixes: PYSIDE-945
Fixes: PYSIDE-1052
Change-Id: Ic09f02ece3a90325519e42e4e39719beb0c27ae9
Reviewed-by: Christian Tismer <tismer@stackless.com>

1 files changed, 28 insertions, 10 deletions

diff --git a/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/layout.py b/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/layout.py
index bd827f1ee..af8ada065 100644
--- a/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/layout.py
+++ b/sources/shiboken2/shibokenmodule/files.dir/shibokensupport/signature/layout.py
@@ -174,6 +174,13 @@ def make_signature_nameless(signature):
         signature.parameters[key].__class__ = NamelessParameter
 
 
+_POSITIONAL_ONLY         = inspect._POSITIONAL_ONLY
+_POSITIONAL_OR_KEYWORD   = inspect._POSITIONAL_OR_KEYWORD
+_VAR_POSITIONAL          = inspect._VAR_POSITIONAL
+_KEYWORD_ONLY            = inspect._KEYWORD_ONLY
+_VAR_KEYWORD             = inspect._VAR_KEYWORD
+_empty                   = inspect._empty
+
 def create_signature(props, key):
     if not props:
         # empty signatures string
@@ -204,8 +211,8 @@ def create_signature(props, key):
         elif sig_kind == "classmethod":
             varnames = ("klass",) + varnames
         else:
-            raise SystemError("Methods must be function, method, staticmethod or "
-                              "classmethod")
+            raise SystemError("Methods must be function, method, staticmethod"
+                              " or classmethod")
     # calculate the modifications
     defaults = props["defaults"][:]
     if not layout.defaults:
@@ -216,14 +223,25 @@ def create_signature(props, key):
     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)
+    # Build a signature.
+    kind = inspect._POSITIONAL_OR_KEYWORD
+    params = []
+    for idx, name in enumerate(varnames):
+        if name.startswith("**"):
+            kind = _VAR_KEYWORD
+        elif name.startswith("*"):
+            kind = _VAR_POSITIONAL
+        ann = annotations.get(name, _empty)
+        name = name.lstrip("*")
+        defpos = idx - len(varnames) + len(defaults)
+        default = defaults[defpos] if defpos >= 0 else _empty
+        param = inspect.Parameter(name, kind, annotation=ann, default=default)
+        params.append(param)
+        if kind == _VAR_POSITIONAL:
+            kind = _KEYWORD_ONLY
+    sig = inspect.Signature(params,
+           return_annotation=annotations.get('return', _empty),
+           __validate_parameters__=False)
 
     # the special case of nameless parameters
     if not layout.parameter_names: