Small refactoring of duplicate code.

bonobo/execution/node.py

@@ -88,6 +88,12 @@ class NodeExecutionContext(WithStatistics, LoopingExecutionContext):
         # todo add timer
         self.handle_results(input_bag, input_bag.apply(self.wrapped, *self._context))
 
+    def push(self, bag):
+        # MAKE THIS PUBLIC API FOR CONTEXT PROCESSORS !!!
+        # xxx handle error or send in first call to apply(...)?
+        # xxx return value ?
+        bag.apply(self.handle_error) if is_error(bag) else self.send(bag)
+
     def handle_results(self, input_bag, results):
         # self._exec_time += timer.duration
         # Put data onto output channels
@@ -95,10 +101,7 @@ class NodeExecutionContext(WithStatistics, LoopingExecutionContext):
             results = iter_if_not_sequence(results)
         except TypeError:  # not an iterator
             if results:
-                if isinstance(results, ErrorBag):
-                    results.apply(self.handle_error)
-                else:
-                    self.send(_resolve(input_bag, results))
+                self.push(_resolve(input_bag, results))
             else:
                 # case with no result, an execution went through anyway, use for stats.
                 # self._exec_count += 1
@@ -106,21 +109,23 @@ class NodeExecutionContext(WithStatistics, LoopingExecutionContext):
         else:
             while True:  # iterator
                 try:
-                    output = next(results)
+                    result = next(results)
                 except StopIteration:
                     break
                 else:
-                    if isinstance(output, ErrorBag):
-                        output.apply(self.handle_error)
-                    else:
-                        self.send(_resolve(input_bag, output))
+                    self.push(_resolve(input_bag, result))
 
+def is_error(bag):
+    return isinstance(bag, ErrorBag)
 
 def _resolve(input_bag, output):
     # NotModified means to send the input unmodified to output.
     if output is NOT_MODIFIED:
         return input_bag
 
+    if is_error(output):
+        return output
+
     # If it does not look like a bag, let's create one for easier manipulation
     if hasattr(output, 'apply'):
         # Already a bag? Check if we need to set parent.