Porting zerobin to python 3

libs/cherrypy/lib/__init__.py

@@ -3,16 +3,54 @@
 # Deprecated in CherryPy 3.2 -- remove in CherryPy 3.3
 from cherrypy.lib.reprconf import unrepr, modules, attributes
 
-class file_generator(object):
-    """Yield the given input (a file object) in chunks (default 64k). (Core)"""
+def is_iterator(obj):
+    '''Returns a boolean indicating if the object provided implements
+     the iterator protocol (i.e. like a generator). This will return
+     false for objects which iterable, but not iterators themselves.'''
+    from types import GeneratorType
+    if isinstance(obj, GeneratorType):
+        return True
+    elif not hasattr(obj, '__iter__'):
+        return False
+    else:
+        # Types which implement the protocol must return themselves when
+        # invoking 'iter' upon them.
+        return iter(obj) is obj
+        
+def is_closable_iterator(obj):
     
+    # Not an iterator.
+    if not is_iterator(obj):
+        return False
+    
+    # A generator - the easiest thing to deal with.
+    import inspect
+    if inspect.isgenerator(obj):
+        return True
+    
+    # A custom iterator. Look for a close method...
+    if not (hasattr(obj, 'close') and callable(obj.close)):
+        return False
+    
+    #  ... which doesn't require any arguments.
+    try:
+        inspect.getcallargs(obj.close)
+    except TypeError:
+        return False
+    else:
+        return True
+
+class file_generator(object):
+
+    """Yield the given input (a file object) in chunks (default 64k). (Core)"""
+
     def __init__(self, input, chunkSize=65536):
         self.input = input
         self.chunkSize = chunkSize
-    
+
     def __iter__(self):
         return self
-    
+
     def __next__(self):
         chunk = self.input.read(self.chunkSize)
         if chunk:
@@ -23,6 +61,7 @@ class file_generator(object):
             raise StopIteration()
     next = __next__
 
+
 def file_generator_limited(fileobj, count, chunk_size=65536):
     """Yield the given file object in chunks, stopping after `count`
     bytes has been emitted.  Default chunk size is 64kB. (Core)
@@ -36,6 +75,7 @@ def file_generator_limited(fileobj, count, chunk_size=65536):
         remaining -= chunklen
         yield chunk
 
+
 def set_vary_header(response, header_name):
     "Add a Vary header to a response"
     varies = response.headers.get("Vary", "")