[Extension API Extern Generation] Fix a few bugs in extern generation

Properly handle the case of an "object" (one deliberately left undefined in the
idl/json), and fix an off-by-one error in the comment wrapping.
Add tests for each.

BUG=469920

Review URL: https://codereview.chromium.org/1062573004

Cr-Commit-Position: refs/heads/master@{#324063}

tools/json_schema_compiler/code.py

@@ -132,7 +132,7 @@ class Code(object):
 
     # First line has the full maximum length.
     if not new_line and self._code:
-      max_len = self._comment_length - len(self._code[-1].value) - 1
+      max_len = self._comment_length - len(self._code[-1].value)
     else:
       max_len = (self._comment_length - len(''.join(self._line_prefixes)) -
                  len(comment_prefix))

tools/json_schema_compiler/code_test.py

@@ -191,7 +191,7 @@ class CodeTest(unittest.TestCase):
         ' */',
         output)
 
-  def testSameLineAppendAndConcat(self):
+  def testSameLineAppendConcatComment(self):
     c = Code()
     c.Append('This is a line.')
     c.Append('This too.', new_line=False)
@@ -199,6 +199,15 @@ class CodeTest(unittest.TestCase):
     d.Append('And this.')
     c.Concat(d, new_line=False)
     self.assertEquals('This is a line.This too.And this.', c.Render())
+    c = Code()
+    c.Append('This is a')
+    c.Comment(' spectacular 80-character line thingy ' +
+                  'that fits wonderfully everywhere.',
+              comment_prefix='',
+              new_line=False)
+    self.assertEquals('This is a spectacular 80-character line thingy that ' +
+                          'fits wonderfully everywhere.',
+                      c.Render())
 
 if __name__ == '__main__':
   unittest.main()

tools/json_schema_compiler/js_externs_generator.py

@@ -126,7 +126,7 @@ class _Generator(object):
     """Given an OrderedDict of properties, returns a Code containing the
        description of an object.
     """
-    if not properties: return ''
+    if not properties: return Code()
 
     c = Code()
     c.Sblock('{')
@@ -212,38 +212,39 @@ class _Generator(object):
 
   def _TypeToJsType(self, js_type):
     """Converts a model.Type to a JS type (number, Array, etc.)"""
-    c = Code()
     if js_type.property_type in (PropertyType.INTEGER, PropertyType.DOUBLE):
-      c.Append('number')
-    elif js_type.property_type is PropertyType.OBJECT:
-      c = self._GenerateObjectDefinition(js_type.properties)
-    elif js_type.property_type is PropertyType.ARRAY:
-      (c.Append('!Array<').
+      return Code().Append('number')
+    if js_type.property_type is PropertyType.OBJECT:
+      if js_type.properties:
+        return self._GenerateObjectDefinition(js_type.properties)
+      return Code().Append('Object')
+    if js_type.property_type is PropertyType.ARRAY:
+      return (Code().Append('!Array<').
            Concat(self._TypeToJsType(js_type.item_type), new_line=False).
            Append('>', new_line=False))
-    elif js_type.property_type is PropertyType.REF:
+    if js_type.property_type is PropertyType.REF:
       ref_type = js_type.ref_type
       # Enums are defined as chrome.fooAPI.MyEnum, but types are defined simply
       # as MyType.
       if self._namespace.types[ref_type].property_type is PropertyType.ENUM:
         ref_type = '!chrome.%s.%s' % (self._namespace.name, ref_type)
-      c.Append(ref_type)
-    elif js_type.property_type is PropertyType.CHOICES:
+      return Code().Append(ref_type)
+    if js_type.property_type is PropertyType.CHOICES:
+      c = Code()
       c.Append('(')
       for i, choice in enumerate(js_type.choices):
         c.Concat(self._TypeToJsType(choice), new_line=False)
         if i is not len(js_type.choices) - 1:
           c.Append('|', new_line=False)
       c.Append(')', new_line=False)
-    elif js_type.property_type is PropertyType.FUNCTION:
-      c = self._FunctionToJsFunction(js_type.function)
-    elif js_type.property_type is PropertyType.ANY:
-      c.Append('*')
-    elif js_type.property_type.is_fundamental:
-      c.Append(js_type.property_type.name)
-    else:
-      c.Append('?') # TODO(tbreisacher): Make this more specific.
-    return c
+      return c
+    if js_type.property_type is PropertyType.FUNCTION:
+      return self._FunctionToJsFunction(js_type.function)
+    if js_type.property_type is PropertyType.ANY:
+      return Code().Append('*')
+    if js_type.property_type.is_fundamental:
+      return Code().Append(js_type.property_type.name)
+    return Code().Append('?') # TODO(tbreisacher): Make this more specific.
 
   def _GenerateFunction(self, function):
     """Generates the code representing a function, including its documentation.

tools/json_schema_compiler/js_externs_generator_test.py

@@ -43,6 +43,7 @@ namespace fakeApi {
     Bar obj;
     long? maybe;
     (DOMString or Greek or long[]) choice;
+    object plainObj;
   };
 
   callback VoidCallback = void();
@@ -114,7 +115,8 @@ var Bar;
  *   anythingGoes: !Array<*>,
  *   obj: Bar,
  *   maybe: (number|undefined),
- *   choice: (string|!chrome.fakeApi.Greek|!Array<number>)
+ *   choice: (string|!chrome.fakeApi.Greek|!Array<number>),
+ *   plainObj: Object
  * }}
  * @see https://developer.chrome.com/extensions/fakeApi#type-Baz
  */