Lazily load extension API schemas

tools/json_schema_compiler/schema_loader.py

Index: tools/json_schema_compiler/schema_loader.py
diff --git a/tools/json_schema_compiler/schema_loader.py b/tools/json_schema_compiler/schema_loader.py
new file mode 100644
index 0000000000000000000000000000000000000000..c434dc167462a26a6e913a28e50d8b9bb79a4126
--- /dev/null
+++ b/tools/json_schema_compiler/schema_loader.py
@@ -0,0 +1,53 @@
+# Copyright (c) 2012 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.
+
+import os
+import sys
+
+import idl_schema
+import json_schema
+from model import Model
+
+class SchemaLoader(object):
+  '''Resolves a type name into the namespace the type belongs to.
+  '''
+  def __init__(self, api_path):
+    self._api_path = api_path
+
+  def ResolveType(self, full_name, default_namespace):
+    name_parts = full_name.rsplit('.', 1)
+    if len(name_parts) == 1:
+      if full_name not in default_namespace.types:
+        return None
+      return default_namespace
+    namespace_name, type_name = name_parts
+    real_name = None
+    for ext in ['json', 'idl']:
+      filename = '%s.%s' % (namespace_name, ext)
+      if os.path.exists(filename):
+        real_name = filename
+        break
+    if real_name is None:
+      return None
+    namespace = Model().AddNamespace(self.LoadSchema(real_name)[0],
+                                     os.path.join(self._api_path, real_name))
+    if type_name not in namespace.types:
+      return None
+    return namespace
+
+  def LoadSchema(self, schema):
+    schema_filename, schema_extension = os.path.splitext(schema)
+
+    if schema_extension == '.json':
+      api_defs = json_schema.Load(schema)
+    elif schema_extension == '.idl':
+      api_defs = idl_schema.Load(schema)
+    else:
+      sys.exit('Did not recognize file extension %s for schema %s' %
+               (schema_extension, schema))
+    if len(api_defs) != 1:
+      sys.exit('File %s has multiple schemas. Files are only allowed to contain'
+               'a single schema.' % schema)
+
+    return api_defs