mojom: Add associative arrays to the mojom language.

mojo/public/tools/bindings/pylib/mojom/parse/translate.py

Index: mojo/public/tools/bindings/pylib/mojom/parse/translate.py
diff --git a/mojo/public/tools/bindings/pylib/mojom/parse/translate.py b/mojo/public/tools/bindings/pylib/mojom/parse/translate.py
index 77e92c5b8b2065c59ebb7453aa18b7b298cce3f9..f5de48a4952325ed81e10e6bc2b4f15551ba55f1 100644
--- a/mojo/public/tools/bindings/pylib/mojom/parse/translate.py
+++ b/mojo/public/tools/bindings/pylib/mojom/parse/translate.py
@@ -18,7 +18,7 @@ def _MapTreeForType(func, tree, type_to_map):
 
 _FIXED_ARRAY_REGEXP = re.compile(r'\[[0-9]+\]')
 
-def _MapKind(kind):
+def MapKind(kind):
   map_to_kind = {'bool': 'b',
                  'int8': 'i8',
                  'int16': 'i16',
@@ -37,27 +37,36 @@ def _MapKind(kind):
                  'handle<message_pipe>': 'h:m',
                  'handle<shared_buffer>': 'h:s'}
   if kind.endswith('?'):
-    base_kind = _MapKind(kind[0:-1])
+    base_kind = MapKind(kind[0:-1])
     # NOTE: This doesn't rule out enum types. Those will be detected later, when
     # cross-reference is established.
-    reference_kinds = ('s', 'h', 'a', 'r', 'x')
+    reference_kinds = ('m', 's', 'h', 'a', 'r', 'x')
     if base_kind[0] not in reference_kinds:
       raise Exception(
           'A type (spec "%s") cannot be made nullable' % base_kind)
     return '?' + base_kind
+  first_curly = kind.find('{')
+  if first_curly != -1:
+    # We want to parse associative arrays from left to right as much as
+    # possible. So remove remove the first associative array key as the key
+    # type, and pass the rest (which may be an array) to ourselves recursively.
+    closing_curly = kind.find('}', first_curly)
+    key = kind[first_curly+1:closing_curly]
+    rest = kind[0:first_curly] + kind[closing_curly+1:]
+    return 'm[' + MapKind(key) + '][' + MapKind(rest) + ']'
   if kind.endswith('[]'):
     typename = kind[0:-2]
     if _FIXED_ARRAY_REGEXP.search(typename):
       raise Exception('Arrays of fixed sized arrays not supported')
-    return 'a:' + _MapKind(typename)
+    return 'a:' + MapKind(typename)
   if kind.endswith(']'):
     lbracket = kind.rfind('[')
     typename = kind[0:lbracket]
     if typename.find('[') != -1:
       raise Exception('Fixed sized arrays of arrays not supported')
-    return 'a' + kind[lbracket+1:-1] + ':' + _MapKind(typename)
+    return 'a' + kind[lbracket+1:-1] + ':' + MapKind(typename)
   if kind.endswith('&'):
-    return 'r:' + _MapKind(kind[0:-1])
+    return 'r:' + MapKind(kind[0:-1])
   if kind in map_to_kind:
     return map_to_kind[kind]
   return 'x:' + kind
@@ -83,7 +92,7 @@ def _EnumToDict(enum):
 def _ConstToDict(const):
   assert isinstance(const, ast.Const)
   return {'name': const.name,
-          'kind': _MapKind(const.typename),
+          'kind': MapKind(const.typename),
           'value': const.value}
 
 
@@ -96,7 +105,7 @@ class _MojomBuilder(object):
       def StructFieldToDict(struct_field):
         assert isinstance(struct_field, ast.StructField)
         return {'name': struct_field.name,
-                'kind': _MapKind(struct_field.typename),
+                'kind': MapKind(struct_field.typename),
                 'ordinal': struct_field.ordinal.value \
                     if struct_field.ordinal else None,
                 'default': struct_field.default_value}
@@ -115,7 +124,7 @@ class _MojomBuilder(object):
         def ParameterToDict(param):
           assert isinstance(param, ast.Parameter)
           return {'name': param.name,
-                  'kind': _MapKind(param.typename),
+                  'kind': MapKind(param.typename),
                   'ordinal': param.ordinal.value if param.ordinal else None}
 
         assert isinstance(method, ast.Method)