track embedded python distribution

python/gevent/util.py

@@ -0,0 +1,60 @@
+# Copyright (c) 2009 Denis Bilenko. See LICENSE for details.
+"""
+Low-level utilities.
+"""
+
+from __future__ import absolute_import
+
+import functools
+
+__all__ = ['wrap_errors']
+
+
+class wrap_errors(object):
+    """
+    Helper to make function return an exception, rather than raise it.
+
+    Because every exception that is unhandled by greenlet will be logged,
+    it is desirable to prevent non-error exceptions from leaving a greenlet.
+    This can done with a simple ``try/except`` construct::
+
+        def wrapped_func(*args, **kwargs):
+            try:
+                return func(*args, **kwargs)
+            except (TypeError, ValueError, AttributeError) as ex:
+                return ex
+
+    This class provides a shortcut to write that in one line::
+
+        wrapped_func = wrap_errors((TypeError, ValueError, AttributeError), func)
+
+    It also preserves ``__str__`` and ``__repr__`` of the original function.
+    """
+    # QQQ could also support using wrap_errors as a decorator
+
+    def __init__(self, errors, func):
+        """
+        Calling this makes a new function from *func*, such that it catches *errors* (an
+        :exc:`BaseException` subclass, or a tuple of :exc:`BaseException` subclasses) and
+        return it as a value.
+        """
+        self.__errors = errors
+        self.__func = func
+        # Set __doc__, __wrapped__, etc, especially useful on Python 3.
+        functools.update_wrapper(self, func)
+
+    def __call__(self, *args, **kwargs):
+        func = self.__func
+        try:
+            return func(*args, **kwargs)
+        except self.__errors as ex:
+            return ex
+
+    def __str__(self):
+        return str(self.__func)
+
+    def __repr__(self):
+        return repr(self.__func)
+
+    def __getattr__(self, name):
+        return getattr(self.__func, name)