Make SchemaLoader independent of current working directory.

tools/json_schema_compiler/schema_loader.py

 # 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.
+
+  Properties:
+  - |display_path| path to the directory with the API header files, intended for
+  use with the Model.
+  - |real_path| path to the directory with the API header files, used for file
+  access.
   '''
-  def __init__(self, api_path):
-    self._api_path = api_path
+  def __init__(self, display_path, real_path):
+    self._display_path = display_path
+    self._real_path = real_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):
+      filepath = os.path.join(self._real_path, filename);
+      if os.path.exists(filepath):
         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))
+    namespace = Model().AddNamespace(
+        self.LoadSchema(real_name)[0],
+        os.path.join(self._display_path, real_name))
     if type_name not in namespace.types:
       return None
     return namespace
 
   def LoadSchema(self, schema):
+    '''Load a schema definition. The schema parameter must be a file name
+    without any path component - the file is loaded from the path defined by
+    the real_path argument passed to the constructor.'''
     schema_filename, schema_extension = os.path.splitext(schema)
 
+    schema_path = os.path.join(self._real_path, schema);
     if schema_extension == '.json':
-      api_defs = json_schema.Load(schema)
+      api_defs = json_schema.Load(schema_path)
     elif schema_extension == '.idl':
-      api_defs = idl_schema.Load(schema)
+      api_defs = idl_schema.Load(schema_path)
     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