Add js_interface_generator for generating extensions interfaces

tools/json_schema_compiler/js_interface_generator.py

+# Copyright 2015 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.
+"""
+Generator that produces an interface file for the Closure Compiler.
+Note: This is a work in progress, and generated externs may require tweaking.

[michaelpg, 2015/12/04 21:02:19]

externs -> interfaces

[stevenjb, 2015/12/07 18:31:24]

Done.

+"""
+
+from code import Code
+from js_util import JsUtil
+from model import *
+from schema_util import *
+
+import os
+import sys
+import re
+
+class JsInterfaceGenerator(object):
+  def Generate(self, namespace):
+    return _Generator(namespace).Generate()
+
+  def GetHeader(tool, namespace):
+    """Returns the file header text.
+    """
+    js_util = JsUtil();
+    return (js_util.GetLicense() + '\n' +
+            js_util.GetInfo(tool) + '\n' +
+            ('/** @fileoverview Interface for %s that can be overriden. */' %
+             namespace))

[michaelpg, 2015/12/04 21:02:19]

can you add the assertNotReached like here?
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/res...

otherwise if someone tries to execute this file for some reason, they'll get an
unhelpful failure if it has any events since ChromeEvent is just an extern

[stevenjb, 2015/12/07 18:31:24]

Based on Devlin's confusion, yeah, I'll do that. It seemed a bit awkward to me,
but I guess it makes sense.

+  GetHeader = staticmethod(GetHeader)
+
+class _Generator(object):
+  def __init__(self, namespace):
+    self._namespace = namespace
+    first = namespace.name[0].upper()
+    rest = namespace.name[1:]
+    self._interface = first + rest
+    self._js_util = JsUtil()
+
+  def Generate(self):
+    """Generates a Code object with the schema for the entire namespace.
+    """
+    c = Code()
+    (c.Append(JsInterfaceGenerator.GetHeader(sys.argv[0],
+                                             self._namespace.name))
+        .Append())
+
+    c.Cblock(self._GenerateInterfaceObject())
+
+    c.Sblock('%s.prototype = {' % self._interface)
+
+    for function in self._namespace.functions.values():
+      c.Cblock(self._GenerateFunction(function))
+
+    for event in self._namespace.events.values():
+      c.Cblock(self._GenerateEvent(event))
+
+    c.TrimTrailingNewlines()
+
+    c.Eblock('};')
+
+    return c
+
+  def _GenerateInterfaceObject(self):
+    """Generates the code creating the interface object.
+       For example:
+       /** @interface */
+       function SettingsPrivate() {}
+    """
+    c = Code()
+    (c.Append('/** @interface */')
+      .Append('function %s() {}' % self._interface))
+    return c
+
+  def _GenerateFunction(self, function):
+    """Generates the inteface for a function, including a JSDoc comment.
+    """
+    c = Code()
+    if function.deprecated:
+      return c
+
+    (c.Concat(self._js_util.GenerateFunctionJsDoc(self._namespace.name,
+                                                  function))
+      .Append('%s: assertNotReached,' % (function.name)))
+
+    return c
+
+  def _GenerateEvent(self, event):
+    """Generates the interface for an event.
+    """
+    c = Code()
+    c.Sblock(line='/**', line_prefix=' * ')
+    if (event.description):
+      c.Comment(event.description, comment_prefix='')
+    c.Append('@type {!ChromeEvent}')
+    c.Append(self._js_util.GenerateSeeLink(self._namespace.name, 'event',
+                                           event.name))
+    c.Eblock(' */')
+    c.Append('%s: new ChromeEvent(),' % (event.name))
+    return c