chrome/renderer/resources/extensions/utils.js

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 var schemaRegistry = requireNative('schema_registry');
   6 var CHECK = requireNative('logging').CHECK;
   7 var WARNING = requireNative('logging').WARNING;
   8
   9 // An object forEach. Calls |f| with each (key, value) pair of |obj|, using
  10 // |self| as the target.
  11 function forEach(obj, f, self) {
  12   for (var key in obj) {
  13     if ($Object.hasOwnProperty(obj, key))
  14       $Function.call(f, self, key, obj[key]);
  15   }
  16 }
  17
  18 // Assuming |array_of_dictionaries| is structured like this:
  19 // [{id: 1, ... }, {id: 2, ...}, ...], you can use
  20 // lookup(array_of_dictionaries, 'id', 2) to get the dictionary with id == 2.
  21 function lookup(array_of_dictionaries, field, value) {
  22   var filter = function (dict) {return dict[field] == value;};
  23   var matches = array_of_dictionaries.filter(filter);
  24   if (matches.length == 0) {
  25     return undefined;
  26   } else if (matches.length == 1) {
  27     return matches[0]
  28   } else {
  29     throw new Error("Failed lookup of field '" + field + "' with value '" +
  30                     value + "'");
  31   }
  32 }
  33
  34 function loadTypeSchema(typeName, defaultSchema) {
  35   var parts = $String.split(typeName, '.');
  36   if (parts.length == 1) {
  37     if (defaultSchema == null) {
  38       WARNING('Trying to reference "' + typeName + '" ' +
  39               'with neither namespace nor default schema.');
  40       return null;
  41     }
  42     var types = defaultSchema.types;
  43   } else {
  44     var schemaName = $Array.join($Array.slice(parts, 0, parts.length - 1), '.');
  45     var types = schemaRegistry.GetSchema(schemaName).types;
  46   }
  47   for (var i = 0; i < types.length; ++i) {
  48     if (types[i].id == typeName)
  49       return types[i];
  50   }
  51   return null;
  52 }
  53
  54 // expose takes a private class implementation |cls| and exposes a subset of its
  55 // methods |funcs| and properties |props| in a public wrapper class that it
  56 // returns.
  57 function expose(cls, funcs, props) {
  58   function publicClass() {
  59     var privateObj = $Object.create(cls.prototype);
  60     $Function.apply(cls, privateObj, arguments);
  61     privateObj.wrapper = this;
  62     privates(this).impl = privateObj;
  63   }
  64
  65   if (funcs) {
  66     $Array.forEach(funcs, function(func) {
  67       publicClass.prototype[func] = function() {
  68         var impl = privates(this).impl;
  69         return $Function.apply(impl[func], impl, arguments);
  70       };
  71     });
  72   }
  73
  74   if (props) {
  75     $Array.forEach(props, function(prop) {
  76       $Object.defineProperty(publicClass.prototype, prop, {
  77         enumerable: true,
  78         get: function() {
  79           return privates(this).impl[prop];
  80         },
  81         set: function(value) {
  82           var impl = privates(this).impl;
  83           delete impl[prop];
  84           impl[prop] = value;
  85         }
  86       });
  87     });
  88   }
  89
  90   return publicClass;
  91 }
  92
  93 exports.forEach = forEach;
  94 exports.loadTypeSchema = loadTypeSchema;
  95 exports.lookup = lookup;
  96 exports.expose = expose;