Move modules-dependent IDL statements out of core by supporting 'implements' in RHS interface

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 40 matching lines @@
 # We use regular expressions for parsing; this is incorrect (Web IDL is not a
 # regular language), but simple and sufficient in practice.
 # Leading and trailing context (e.g. following '{') used to avoid false matches.
 ################################################################################
 
 def get_partial_interface_name_from_idl(file_contents):
     match = re.search(r'partial\s+interface\s+(\w+)\s*{', file_contents)
     return match and match.group(1)
 
 
-def get_implemented_interfaces_from_idl(file_contents, interface_name):
+def get_implements_from_idl(file_contents, interface_name):
     # Rule is: identifier-A implements identifier-B;
     # http://www.w3.org/TR/WebIDL/#idl-implements-statements
-    def get_implemented(left_identifier, right_identifier):
-        # identifier-A must be the current interface
-        if left_identifier != interface_name:
-            raise IdlBadFilenameError("Identifier on the left of the 'implements' statement should be %s in %s.idl, but found %s" % (interface_name, interface_name, left_identifier))
-        return right_identifier
-
+    # Returns two lists of interfaces that contain identifier-As and identifier-Bs.

[Nils Barth (inactive), 2014/05/08 02:46:47]

Could you wrap at 80 cols?

Actually, could you make this into a docstring?
"""Returns lists of implementing and implemented interfaces.

Rule is: ...
"""

+    # The 'implements' statements are supported in both identifier-A IDL and identifier-B IDL
+    # to avoid potential layering violation.
     implements_re = (r'^\s*'
                      r'(\w+)\s+'
                      r'implements\s+'
                      r'(\w+)\s*'
                      r';')
     implements_matches = re.finditer(implements_re, file_contents, re.MULTILINE)
     implements_pairs = [(match.group(1), match.group(2))
                         for match in implements_matches]

[Nils Barth (inactive), 2014/05/08 02:46:47]

Could you add a check that *one* of the interfaces is included in the implements
statement?
foreign_implements = [(left, right) for left, right in implements_pairs
                      if interface_name not in (left, right)]
if foreign_implements:
    raise ...

-    return [get_implemented(left, right) for left, right in implements_pairs]
+    A_interfaces = []

[Nils Barth (inactive), 2014/05/08 02:46:47]

List comprehensions please:
A_interfaces = [left for left, right in implements_pairs
                if right == interface_name]
B_interfaces = [right for left, right in implements_pairs
                if left == interface_name]

+    B_interfaces = []
+    for left, right in implements_pairs:
+        if left == interface_name:
+            B_interfaces.append(right)
+        elif right == interface_name:
+            A_interfaces.append(left)
+    return (A_interfaces, B_interfaces)

[Nils Barth (inactive), 2014/05/08 02:46:47]

No parens.

 
 
 def is_callback_interface_from_idl(file_contents):
     match = re.search(r'callback\s+interface\s+\w+\s*{', file_contents)
     return bool(match)
 
 
 def get_parent_interface(file_contents):
     match = re.search(r'interface\s+'
                       r'\w+\s*'
@@ skipping 34 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)))