Get rid of System classes for backend generators.

lib/html/scripts/systembase.py

 #!/usr/bin/python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """This module provides base functionality for systems to generate
 Dart APIs from the IDL database."""
 
 import os
 from generator import *
 
 class System(object):
   """A System generates all the files for one implementation.
 
   This is a base class for all the specific systems.
   The life-cycle of a System is:
   - construction (__init__)
-  - (InterfaceGenerator | ProcessCallback)*  # for each IDL interface
+  - (ProcessInterface)*  # for each IDL interface
   """
 
   def __init__(self, options):
     self._templates = options.templates
     self._database = options.database
     self._type_registry = options.type_registry
     self._renamer = options.renamer
 
   def ProcessInterface(self, interface):
     """Processes an interface that is not a callback function."""
     pass
 
-  def ProcessCallback(self, interface, info):
-    """Processes an interface that is a callback function."""
-    pass
-
-
   # Helper methods used by several systems.
 
   def _BaseDefines(self, interface):
     """Returns a set of names (strings) for members defined in a base class.
     """
     def WalkParentChain(interface):
       if interface.parents:
         # Only consider primary parent, secondary parents are not on the
         # implementation class inheritance chain.
         parent = interface.parents[0]
         if IsDartCollectionType(parent.type.id):
           return
         if self._database.HasInterface(parent.type.id):
           parent_interface = self._database.GetInterface(parent.type.id)
           for attr in parent_interface.attributes:
             result.add(attr.id)
           for op in parent_interface.operations:
             result.add(op.id)
           WalkParentChain(parent_interface)
 
     result = set()
     WalkParentChain(interface)
     return result
 
 class BaseGenerator(object):
-  def __init__(self, database, interface):
+  def __init__(self, database, type_registry, interface):
     self._database = database
+    self._type_registry = type_registry
     self._interface = interface
 
   def Generate(self):
+    if 'Callback' in self._interface.ext_attrs:
+      handlers = [operation for operation in self._interface.operations
+                  if operation.id == 'handleEvent']
+      info = AnalyzeOperation(self._interface, handlers)
+      self.GenerateCallback(info)
+      return
+
     self.StartInterface()
     self.AddMembers(self._interface)
     self.AddSecondaryMembers(self._interface)
     self.FinishInterface()
 
+  def GenerateCallback(self, info):
+    pass
+
   def AddMembers(self, interface):
     for const in sorted(interface.constants, ConstantOutputOrder):
       self.AddConstant(const)
 
     for attr in interface.attributes:
       if attr.type.id != 'EventListener':
         self.AddAttribute(attr)
 
     # The implementation should define an indexer if the interface directly
     # extends List.
@@ skipping 83 matching lines @@
 
     result = []
     if interface.parents:
       parent = interface.parents[0]
       if IsPureInterface(parent.type.id):
         walk(interface.parents)
       else:
         walk(interface.parents[1:])
     return result
 
+  def _TypeInfo(self, type_name):
+    return self._type_registry.TypeInfo(type_name)
+
   def _DartType(self, type_name):
-    return self._system._type_registry.DartType(type_name)
+    return self._type_registry.DartType(type_name)
 
 
 class GeneratorOptions(object):
   def __init__(self, templates, database, type_registry, renamer):
     self.templates = templates
     self.database = database
     self.type_registry = type_registry
     self.renamer = renamer
 
 
 def IsReadOnly(attribute):
   return attribute.is_read_only or 'Replaceable' in attribute.ext_attrs