1 files changed, 34 insertions, 0 deletions
diff --git a/paste/wareweb/event.py b/paste/wareweb/event.py
new file mode 100644
index 0000000..5376d63
--- /dev/null
+++ b/paste/wareweb/event.py
@@ -0,0 +1,34 @@
+class Continue:
+    """
+    This class is a singleton (never meant to be instantiated) that
+    represents a kind of no-op return from a class.
+    """
+    def __init__(self):
+        assert False, (
+            "Continue cannot be instantiated (use the class object "
+            "itself)")
+
+def wrap_func(func):
+    name = func.__name__
+    def replacement_func(actor, *args, **kw):
+        # @@: It's really more of an "inner_value" than "next_method"
+        kw['next_method'] = func
+        result = raise_event('start_%s' % name, actor, *args, **kw)
+        del kw['next_method']
+        if result is Continue:
+            value = func(actor, *args, **kw)
+        else:
+            return result
+        result = raise_event('end_%s' % name, actor, value, *args, **kw)
+        if result is Continue:
+            return value
+        return result
+    replacement_func.__name__ = name
+    return replacement_func
+
+def raise_event(name, actor, *args, **kw):
+    for listener in actor.listeners:
+        value = listener(name, actor, *args, **kw)
+        if value is not Continue:
+            return value
+    return Continue