[bindings] partial interfaces should not violate componentization

Source/bindings/scripts/utilities.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Utility functions (file reading, simple IDL parsing by regexes) for IDL build.
 
 Design doc: http://www.chromium.org/developers/design-documents/idl-build
 """
 
 import os
@@ skipping 13 matching lines @@
 
 def idl_filename_to_interface_name(idl_filename):
     # interface name is the root of the basename: InterfaceName.idl
     return os.path.splitext(os.path.basename(idl_filename))[0]
 
 
 def idl_filename_to_component(idl_filename):
     path = os.path.dirname(os.path.realpath(idl_filename))
     while path:
         dirname, basename = os.path.split(path)
+        if not basename:
+            break
         if basename.lower() in KNOWN_COMPONENTS:
             return basename.lower()
         path = dirname
-    raise 'Unknown component type for %s' % idl_filename
+    raise Exception('Unknown component type for %s' % idl_filename)
+
+
+# See whether "component" can depend on "referred_component" or not:
+# Suppose that we have interface X and Y:
+# - if X is a partial interface and Y is the original interface,
+#   use is_valid_component_dependency(X, Y).
+# - if X implements Y, use is_valid_component_dependency(X, Y)
+# Suppose that X is a cpp file and Y is a header file:
+# - if X includes Y, use is_valid_component_dependency(X, Y)
+def is_valid_component_dependency(component, referred_component):
+    assert component in KNOWN_COMPONENTS
+    assert referred_component in KNOWN_COMPONENTS
+    if component == 'core' and referred_component == 'modules':
+        return False
+    return True
 
 
 ################################################################################
 # Basic file reading/writing
 ################################################################################
 
 def get_file_contents(filename):
     with open(filename) as f:
         return f.read()
 
@@ skipping 164 matching lines @@
 
 def get_put_forward_interfaces_from_idl(file_contents):
     put_forwards_pattern = (r'\[[^\]]*PutForwards=[^\]]*\]\s+'
                             r'readonly\s+'
                             r'attribute\s+'
                             r'(\w+)')
     return sorted(set(match.group(1)
                       for match in re.finditer(put_forwards_pattern,
                                                file_contents,
                                                flags=re.DOTALL)))