1 files changed, 111 insertions, 13 deletions

diff --git a/Cython/Utility/CpdefEnums.pyx b/Cython/Utility/CpdefEnums.pyx
index 148d776c2..39377b30c 100644
--- a/Cython/Utility/CpdefEnums.pyx
+++ b/Cython/Utility/CpdefEnums.pyx
@@ -6,10 +6,11 @@ cdef extern from *:
     int PY_VERSION_HEX
 
 cdef object __Pyx_OrderedDict
-if PY_VERSION_HEX >= 0x02070000:
-    from collections import OrderedDict as __Pyx_OrderedDict
-else:
+
+if PY_VERSION_HEX >= 0x03060000:
     __Pyx_OrderedDict = dict
+else:
+    from collections import OrderedDict as __Pyx_OrderedDict
 
 @cython.internal
 cdef class __Pyx_EnumMeta(type):
@@ -23,8 +24,7 @@ cdef class __Pyx_EnumMeta(type):
 
 # @cython.internal
 cdef object __Pyx_EnumBase
-class __Pyx_EnumBase(int):
-    __metaclass__ = __Pyx_EnumMeta
+class __Pyx_EnumBase(int, metaclass=__Pyx_EnumMeta):
     def __new__(cls, value, name=None):
         for v in cls:
             if v == value:
@@ -44,23 +44,121 @@ class __Pyx_EnumBase(int):
 if PY_VERSION_HEX >= 0x03040000:
     from enum import IntEnum as __Pyx_EnumBase
 
+cdef object __Pyx_FlagBase
+class __Pyx_FlagBase(int, metaclass=__Pyx_EnumMeta):
+    def __new__(cls, value, name=None):
+        for v in cls:
+            if v == value:
+                return v
+        res = int.__new__(cls, value)
+        if name is None:
+            # some bitwise combination, no validation here
+            res.name = ""
+        else:
+            res.name = name
+            setattr(cls, name, res)
+            cls.__members__[name] = res
+        return res
+    def __repr__(self):
+        return "<%s.%s: %d>" % (self.__class__.__name__, self.name, self)
+    def __str__(self):
+        return "%s.%s" % (self.__class__.__name__, self.name)
+
+if PY_VERSION_HEX >= 0x03060000:
+    from enum import IntFlag as __Pyx_FlagBase
+
 #################### EnumType ####################
 #@requires: EnumBase
 
+cdef extern from *:
+    object {{enum_to_pyint_func}}({{name}} value)
+
 cdef dict __Pyx_globals = globals()
-if PY_VERSION_HEX >= 0x03040000:
-    # create new IntEnum()
-    {{name}} = __Pyx_EnumBase('{{name}}', __Pyx_OrderedDict([
+if PY_VERSION_HEX >= 0x03060000:
+    # create new IntFlag() - the assumption is that C enums are sufficiently commonly
+    # used as flags that this is the most appropriate base class
+    {{name}} = __Pyx_FlagBase('{{name}}', [
         {{for item in items}}
-        ('{{item}}', {{item}}),
+        ('{{item}}', {{enum_to_pyint_func}}({{item}})),
         {{endfor}}
-    ]))
+        # Try to look up the module name dynamically if possible
+    ], module=__Pyx_globals.get("__module__", '{{static_modname}}'))
+
+    if PY_VERSION_HEX >= 0x030B0000:
+        # Python 3.11 starts making the behaviour of flags stricter
+        # (only including powers of 2 when iterating). Since we're using
+        # "flag" because C enums *might* be used as flags, not because
+        # we want strict flag behaviour, manually undo some of this.
+        {{name}}._member_names_ = list({{name}}.__members__)
+
+    {{if enum_doc is not None}}
+    {{name}}.__doc__ = {{ repr(enum_doc) }}
+    {{endif}}
+
     {{for item in items}}
     __Pyx_globals['{{item}}'] = {{name}}.{{item}}
     {{endfor}}
 else:
-    class {{name}}(__Pyx_EnumBase):
-        pass
+    class {{name}}(__Pyx_FlagBase):
+        {{ repr(enum_doc) if enum_doc is not None else 'pass' }}
+    {{for item in items}}
+    __Pyx_globals['{{item}}'] = {{name}}({{enum_to_pyint_func}}({{item}}), '{{item}}')
+    {{endfor}}
+
+#################### CppScopedEnumType ####################
+#@requires: EnumBase
+cdef dict __Pyx_globals = globals()
+
+if PY_VERSION_HEX >= 0x03040000:
+    __Pyx_globals["{{name}}"] = __Pyx_EnumBase('{{name}}', [
+        {{for item in items}}
+        ('{{item}}', <{{underlying_type}}>({{name}}.{{item}})),
+        {{endfor}}
+    ], module=__Pyx_globals.get("__module__", '{{static_modname}}'))
+else:
+    __Pyx_globals["{{name}}"] = type('{{name}}', (__Pyx_EnumBase,), {})
     {{for item in items}}
-    __Pyx_globals['{{item}}'] = {{name}}({{item}}, '{{item}}')
+    __Pyx_globals["{{name}}"](<{{underlying_type}}>({{name}}.{{item}}), '{{item}}')
     {{endfor}}
+
+{{if enum_doc is not None}}
+__Pyx_globals["{{name}}"].__doc__ = {{ repr(enum_doc) }}
+{{endif}}
+
+
+#################### EnumTypeToPy ####################
+
+@cname("{{funcname}}")
+cdef {{funcname}}({{name}} c_val):
+    cdef object __pyx_enum
+    # There's a complication here: the Python enum wrapping is only generated
+    # for enums defined in the same module that they're used in. Therefore, if
+    # the enum was cimported from a different module, we try to import it.
+    # If that fails we return an int equivalent as the next best option.
+{{if module_name}}
+    try:
+        from {{module_name}} import {{name}} as __pyx_enum
+    except ImportError:
+        import warnings
+        warnings.warn(
+            f"enum class {{name}} not importable from {{module_name}}. "
+            "You are probably using a cpdef enum declared in a .pxd file that "
+            "does not have a .py  or .pyx file.")
+        return <{{underlying_type}}>c_val
+{{else}}
+    __pyx_enum = {{name}}
+{{endif}}
+    # TODO - Cython only manages to optimize C enums to a switch currently
+    if 0:
+        pass
+{{for item in items}}
+    elif c_val == {{name}}.{{item}}:
+        return __pyx_enum.{{item}}
+{{endfor}}
+    else:
+        underlying_c_val = <{{underlying_type}}>c_val
+{{if is_flag}}
+        return __pyx_enum(underlying_c_val)
+{{else}}
+        raise ValueError(f"{underlying_c_val} is not a valid {{name}}")
+{{endif}}