fix #21076: turn signal module constants into enums

1 files changed, 84 insertions, 0 deletions

diff --git a/Lib/signal.py b/Lib/signal.py
new file mode 100644
index 0000000..90e5313
--- /dev/null
+++ b/Lib/signal.py
@@ -0,0 +1,84 @@
+import _signal
+from _signal import *
+from functools import wraps as _wraps
+from enum import IntEnum as _IntEnum
+
+_globals = globals()
+
+Signals = _IntEnum(
+    'Signals',
+    {name: value for name, value in _globals.items()
+     if name.isupper()
+        and (name.startswith('SIG') and not name.startswith('SIG_'))
+        or name.startswith('CTRL_')})
+
+class Handlers(_IntEnum):
+    SIG_DFL = _signal.SIG_DFL
+    SIG_IGN = _signal.SIG_IGN
+
+_globals.update(Signals.__members__)
+_globals.update(Handlers.__members__)
+
+if 'pthread_sigmask' in _globals:
+    class Sigmasks(_IntEnum):
+        SIG_BLOCK = _signal.SIG_BLOCK
+        SIG_UNBLOCK = _signal.SIG_UNBLOCK
+        SIG_SETMASK = _signal.SIG_SETMASK
+
+    _globals.update(Sigmasks.__members__)
+
+
+def _int_to_enum(value, enum_klass):
+    """Convert a numeric value to an IntEnum member.
+    If it's not a known member, return the numeric value itself.
+    """
+    try:
+        return enum_klass(value)
+    except ValueError:
+        return value
+
+
+def _enum_to_int(value):
+    """Convert an IntEnum member to a numeric value.
+    If it's not a IntEnum member return the value itself.
+    """
+    try:
+        return int(value)
+    except (ValueError, TypeError):
+        return value
+
+
+@_wraps(_signal.signal)
+def signal(signalnum, handler):
+    handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))
+    return _int_to_enum(handler, Handlers)
+
+
+@_wraps(_signal.getsignal)
+def getsignal(signalnum):
+    handler = _signal.getsignal(signalnum)
+    return _int_to_enum(handler, Handlers)
+
+
+if 'pthread_sigmask' in _globals:
+    @_wraps(_signal.pthread_sigmask)
+    def pthread_sigmask(how, mask):
+        sigs_set = _signal.pthread_sigmask(how, mask)
+        return set(_int_to_enum(x, Signals) for x in sigs_set)
+    pthread_sigmask.__doc__ = _signal.pthread_sigmask.__doc__
+
+
+@_wraps(_signal.sigpending)
+def sigpending():
+    sigs = _signal.sigpending()
+    return set(_int_to_enum(x, Signals) for x in sigs)
+
+
+if 'sigwait' in _globals:
+    @_wraps(_signal.sigwait)
+    def sigwait(sigset):
+        retsig = _signal.sigwait(sigset)
+        return _int_to_enum(retsig, Signals)
+    sigwait.__doc__ = _signal.sigwait
+
+del _globals, _wraps