injector.js

'use strict';

/**
 * @ngdoc function
 * @module ng
 * @name angular.injector
 * @kind function
 *
 * @description
 * Creates an injector object that can be used for retrieving services as well as for
 * dependency injection (see {@link guide/di dependency injection}).
 *

 * @param {Array.<string|Function>} modules A list of module functions or their aliases. See
 *        {@link angular.module}. The `ng` module must be explicitly added.
 * @returns {injector} Injector object. See {@link auto.$injector $injector}.
 *
 * @example
 * Typical usage
 * ```js
 *   // create an injector
 *   var $injector = angular.injector(['ng']);
 *
 *   // use the injector to kick off your application
 *   // use the type inference to auto inject arguments, or use implicit injection
 *   $injector.invoke(function($rootScope, $compile, $document) {
 *     $compile($document)($rootScope);
 *     $rootScope.$digest();
 *   });
 * ```
 *
 * Sometimes you want to get access to the injector of a currently running Angular app
 * from outside Angular. Perhaps, you want to inject and compile some markup after the
 * application has been bootstrapped. You can do this using the extra `injector()` added
 * to JQuery/jqLite elements. See {@link angular.element}.
 *
 * *This is fairly rare but could be the case if a third party library is injecting the
 * markup.*
 *
 * In the following example a new block of HTML containing a `ng-controller`
 * directive is added to the end of the document body by JQuery. We then compile and link
 * it into the current AngularJS scope.
 *
 * ```js
 * var $div = $('<div ng-controller="MyCtrl">{{content.label}}</div>');
 * $(document.body).append($div);
 *
 * angular.element(document).injector().invoke(function($compile) {
 *   var scope = angular.element($div).scope();
 *   $compile($div)(scope);
 * });
 * ```
 */


/**
 * @ngdoc module
 * @name auto
 * @description
 *
 * Implicit module which gets automatically added to each {@link auto.$injector $injector}.
 */

var FN_ARGS = /^function\s*[^\(]*\(\s*([^\)]*)\)/m;
var FN_ARG_SPLIT = /,/;
var FN_ARG = /^\s*(_?)(\S+?)\1\s*$/;
var STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
var $injectorMinErr = minErr('$injector');

function anonFn(fn) {
  // For anonymous functions, showing at the very least the function signature can help in
  // debugging.
  var fnText = fn.toString().replace(STRIP_COMMENTS, ''),
      args = fnText.match(FN_ARGS);
  if (args) {
    return 'function(' + (args[1] || '').replace(/[\s\r\n]+/, ' ') + ')';
  }
  return 'fn';
}

function annotate(fn, strictDi, name) {
  var $inject,
      fnText,
      argDecl,
      last;

  if (typeof fn === 'function') {
    if (!($inject = fn.$inject)) {
      $inject = [];
      if (fn.length) {
        if (strictDi) {
          if (!isString(name) || !name) {
            name = fn.name || anonFn(fn);
          }
          throw $injectorMinErr('strictdi',
            '{0} is not using explicit annotation and cannot be invoked in strict mode', name);
        }
        fnText = fn.toString().replace(STRIP_COMMENTS, '');
        argDecl = fnText.match(FN_ARGS);
        forEach(argDecl[1].split(FN_ARG_SPLIT), function(arg) {
          arg.replace(FN_ARG, function(all, underscore, name) {
            $inject.push(name);
          });
        });
      }
      fn.$inject = $inject;
    }
  } else if (isArray(fn)) {
    last = fn.length - 1;
    assertArgFn(fn[last], 'fn');
    $inject = fn.slice(0, last);
  } else {
    assertArgFn(fn, 'fn', true);
  }
  return $inject;
}

///////////////////////////////////////

/**
 * @ngdoc service
 * @name $injector
 *
 * @description
 *
 * `$injector` is used to retrieve object instances as defined by
 * {@link auto.$provide provider}, instantiate types, invoke methods,
 * and load modules.
 *
 * The following always holds true:
 *
 * ```js
 *   var $injector = angular.injector();
 *   expect($injector.get('$injector')).toBe($injector);
 *   expect($injector.invoke(function($injector) {
 *     return $injector;
 *   })).toBe($injector);
 * ```
 *
 * # Injection Function Annotation
 *
 * JavaScript does not have annotations, and annotations are needed for dependency injection. The
 * following are all valid ways of annotating function with injection arguments and are equivalent.
 *
 * ```js
 *   // inferred (only works if code not minified/obfuscated)
 *   $injector.invoke(function(serviceA){});
 *
 *   // annotated
 *   function explicit(serviceA) {};
 *   explicit.$inject = ['serviceA'];
 *   $injector.invoke(explicit);
 *
 *   // inline
 *   $injector.invoke(['serviceA', function(serviceA){}]);
 * ```
 *
 * ## Inference
 *
 * In JavaScript calling `toString()` on a function returns the function definition. The definition
 * can then be parsed and the function arguments can be extracted. *NOTE:* This does not work with
 * minification, and obfuscation tools since these tools change the argument names.
 *
 * ## `$inject` Annotation
 * By adding an `$inject` property onto a function the injection parameters can be specified.
 *
 * ## Inline
 * As an array of injection names, where the last item in the array is the function to call.
 */

/**
 * @ngdoc method
 * @name $injector#get
 *
 * @description
 * Return an instance of the service.
 *
 * @param {string} name The name of the instance to retrieve.
 * @return {*} The instance.
 */

/**
 * @ngdoc method
 * @name $injector#invoke
 *
 * @description
 * Invoke the method and supply the method arguments from the `$injector`.
 *
 * @param {!Function} fn The function to invoke. Function parameters are injected according to the
 *   {@link guide/di $inject Annotation} rules.
 * @param {Object=} self The `this` for the invoked method.
 * @param {Object=} locals Optional object. If preset then any argument names are read from this
 *                         object first, before the `$injector` is consulted.
 * @returns {*} the value returned by the invoked `fn` function.
 */

/**
 * @ngdoc method
 * @name $injector#has
 *
 * @description
 * Allows the user to query if the particular service exists.
 *
 * @param {string} name Name of the service to query.
 * @returns {boolean} `true` if injector has given service.
 */

/**
 * @ngdoc method
 * @name $injector#instantiate
 * @description
 * Create a new instance of JS type. The method takes a constructor function, invokes the new
 * operator, and supplies all of the arguments to the constructor function as specified by the
 * constructor annotation.
 *
 * @param {Function} Type Annotated constructor function.
 * @param {Object=} locals Optional object. If preset then any argument names are read from this
 * object first, before the `$injector` is consulted.
 * @returns {Object} new instance of `Type`.
 */

/**
 * @ngdoc method
 * @name $injector#annotate
 *
 * @description
 * Returns an array of service names which the function is requesting for injection. This API is
 * used by the injector to determine which services need to be injected into the function when the
 * function is invoked. There are three ways in which the function can be annotated with the needed
 * dependencies.
 *
 * # Argument names
 *
 * The simplest form is to extract the dependencies from the arguments of the function. This is done
 * by converting the function into a string using `toString()` method and extracting the argument
 * names.
 * ```js
 *   // Given
 *   function MyController($scope, $route) {
 *     // ...
 *   }
 *
 *   // Then
 *   expect(injector.annotate(MyController)).toEqual(['$scope', '$route']);
 * ```
 *
 * This method does not work with code minification / obfuscation. For this reason the following
 * annotation strategies are supported.
 *
 * # The `$inject` property
 *
 * If a function has an `$inject` property and its value is an array of strings, then the strings
 * represent names of services to be injected into the function.
 * ```js
 *   // Given
 *   var MyController = function(obfuscatedScope, obfuscatedRoute) {
 *     // ...
 *   }
 *   // Define function dependencies
 *   MyController['$inject'] = ['$scope', '$route'];
 *
 *   // Then
 *   expect(injector.annotate(MyController)).toEqual(['$scope', '$route']);
 * ```
 *
 * # The array notation
 *
 * It is often desirable to inline Injected functions and that's when setting the `$inject` property
 * is very inconvenient. In these situations using the array notation to specify the dependencies in
 * a way that survives minification is a better choice:
 *
 * ```js
 *   // We wish to write this (not minification / obfuscation safe)
 *   injector.invoke(function($compile, $rootScope) {
 *     // ...
 *   });
 *
 *   // We are forced to write break inlining
 *   var tmpFn = function(obfuscatedCompile, obfuscatedRootScope) {
 *     // ...
 *   };
 *   tmpFn.$inject = ['$compile', '$rootScope'];
 *   injector.invoke(tmpFn);
 *
 *   // To better support inline function the inline annotation is supported
 *   injector.invoke(['$compile', '$rootScope', function(obfCompile, obfRootScope) {
 *     // ...
 *   }]);
 *
 *   // Therefore
 *   expect(injector.annotate(
 *      ['$compile', '$rootScope', function(obfus_$compile, obfus_$rootScope) {}])
 *    ).toEqual(['$compile', '$rootScope']);
 * ```
 *
 * @param {Function|Array.<string|Function>} fn Function for which dependent service names need to
 * be retrieved as described above.
 *
 * @returns {Array.<string>} The names of the services which the function requires.
 */




/**
 * @ngdoc service
 * @name $provide
 *
 * @description
 *
 * The {@link auto.$provide $provide} service has a number of methods for registering components
 * with the {@link auto.$injector $injector}. Many of these functions are also exposed on
 * {@link angular.Module}.
 *
 * An Angular **service** is a singleton object created by a **service factory**.  These **service
 * factories** are functions which, in turn, are created by a **service provider**.
 * The **service providers** are constructor functions. When instantiated they must contain a
 * property called `$get`, which holds the **service factory** function.
 *
 * When you request a service, the {@link auto.$injector $injector} is responsible for finding the
 * correct **service provider**, instantiating it and then calling its `$get` **service factory**
 * function to get the instance of the **service**.
 *
 * Often services have no configuration options and there is no need to add methods to the service
 * provider.  The provider will be no more than a constructor function with a `$get` property. For
 * these cases the {@link auto.$provide $provide} service has additional helper methods to register
 * services without specifying a provider.
 *
 * * {@link auto.$provide#provider provider(provider)} - registers a **service provider** with the
 *     {@link auto.$injector $injector}
 * * {@link auto.$provide#constant constant(obj)} - registers a value/object that can be accessed by
 *     providers and services.
 * * {@link auto.$provide#value value(obj)} - registers a value/object that can only be accessed by
 *     services, not providers.
 * * {@link auto.$provide#factory factory(fn)} - registers a service **factory function**, `fn`,
 *     that will be wrapped in a **service provider** object, whose `$get` property will contain the
 *     given factory function.
 * * {@link auto.$provide#service service(class)} - registers a **constructor function**, `class`
 *     that will be wrapped in a **service provider** object, whose `$get` property will instantiate
 *      a new object using the given constructor function.
 *
 * See the individual methods for more information and examples.
 */

/**
 * @ngdoc method
 * @name $provide#provider
 * @description
 *
 * Register a **provider function** with the {@link auto.$injector $injector}. Provider functions
 * are constructor functions, whose instances are responsible for "providing" a factory for a
 * service.
 *
 * Service provider names start with the name of the service they provide followed by `Provider`.
 * For example, the {@link ng.$log $log} service has a provider called
 * {@link ng.$logProvider $logProvider}.
 *
 * Service provider objects can have additional methods which allow configuration of the provider
 * and its service. Importantly, you can configure what kind of service is created by the `$get`
 * method, or how that service will act. For example, the {@link ng.$logProvider $logProvider} has a
 * method {@link ng.$logProvider#debugEnabled debugEnabled}
 * which lets you specify whether the {@link ng.$log $log} service will log debug messages to the
 * console or not.
 *
 * @param {string} name The name of the instance. NOTE: the provider will be available under `name +
                        'Provider'` key.
 * @param {(Object|function())} provider If the provider is:
 *
 *   - `Object`: then it should have a `$get` method. The `$get` method will be invoked using
 *     {@link auto.$injector#invoke $injector.invoke()} when an instance needs to be created.
 *   - `Constructor`: a new instance of the provider will be created using
 *     {@link auto.$injector#instantiate $injector.instantiate()}, then treated as `object`.
 *
 * @returns {Object} registered provider instance

 * @example
 *
 * The following example shows how to create a simple event tracking service and register it using
 * {@link auto.$provide#provider $provide.provider()}.
 *
 * ```js
 *  // Define the eventTracker provider
 *  function EventTrackerProvider() {
 *    var trackingUrl = '/track';
 *
 *    // A provider method for configuring where the tracked events should been saved
 *    this.setTrackingUrl = function(url) {
 *      trackingUrl = url;
 *    };
 *
 *    // The service factory function
 *    this.$get = ['$http', function($http) {
 *      var trackedEvents = {};
 *      return {
 *        // Call this to track an event
 *        event: function(event) {
 *          var count = trackedEvents[event] || 0;
 *          count += 1;
 *          trackedEvents[event] = count;
 *          return count;
 *        },
 *        // Call this to save the tracked events to the trackingUrl
 *        save: function() {
 *          $http.post(trackingUrl, trackedEvents);
 *        }
 *      };
 *    }];
 *  }
 *
 *  describe('eventTracker', function() {
 *    var postSpy;
 *
 *    beforeEach(module(function($provide) {
 *      // Register the eventTracker provider
 *      $provide.provider('eventTracker', EventTrackerProvider);
 *    }));
 *
 *    beforeEach(module(function(eventTrackerProvider) {
 *      // Configure eventTracker provider
 *      eventTrackerProvider.setTrackingUrl('/custom-track');
 *    }));
 *
 *    it('tracks events', inject(function(eventTracker) {
 *      expect(eventTracker.event('login')).toEqual(1);
 *      expect(eventTracker.event('login')).toEqual(2);
 *    }));
 *
 *    it('saves to the tracking url', inject(function(eventTracker, $http) {
 *      postSpy = spyOn($http, 'post');
 *      eventTracker.event('login');
 *      eventTracker.save();
 *      expect(postSpy).toHaveBeenCalled();
 *      expect(postSpy.mostRecentCall.args[0]).not.toEqual('/track');
 *      expect(postSpy.mostRecentCall.args[0]).toEqual('/custom-track');
 *      expect(postSpy.mostRecentCall.args[1]).toEqual({ 'login': 1 });
 *    }));
 *  });
 * ```
 */

/**
 * @ngdoc method
 * @name $provide#factory
 * @description
 *
 * Register a **service factory**, which will be called to return the service instance.
 * This is short for registering a service where its provider consists of only a `$get` property,
 * which is the given service factory function.
 * You should use {@link auto.$provide#factory $provide.factory(getFn)} if you do not need to
 * configure your service in a provider.
 *
 * @param {string} name The name of the instance.
 * @param {function()} $getFn The $getFn for the instance creation. Internally this is a short hand
 *                            for `$provide.provider(name, {$get: $getFn})`.
 * @returns {Object} registered provider instance
 *
 * @example
 * Here is an example of registering a service
 * ```js
 *   $provide.factory('ping', ['$http', function($http) {
 *     return function ping() {
 *       return $http.send('/ping');
 *     };
 *   }]);
 * ```
 * You would then inject and use this service like this:
 * ```js
 *   someModule.controller('Ctrl', ['ping', function(ping) {
 *     ping();
 *   }]);
 * ```
 */


/**
 * @ngdoc method
 * @name $provide#service
 * @description
 *
 * Register a **service constructor**, which will be invoked with `new` to create the service
 * instance.
 * This is short for registering a service where its provider's `$get` property is the service
 * constructor function that will be used to instantiate the service instance.
 *
 * You should use {@link auto.$provide#service $provide.service(class)} if you define your service
 * as a type/class.
 *
 * @param {string} name The name of the instance.
 * @param {Function} constructor A class (constructor function) that will be instantiated.
 * @returns {Object} registered provider instance
 *
 * @example
 * Here is an example of registering a service using
 * {@link auto.$provide#service $provide.service(class)}.
 * ```js
 *   var Ping = function($http) {
 *     this.$http = $http;
 *   };
 *
 *   Ping.$inject = ['$http'];
 *
 *   Ping.prototype.send = function() {
 *     return this.$http.get('/ping');
 *   };
 *   $provide.service('ping', Ping);
 * ```
 * You would then inject and use this service like this:
 * ```js
 *   someModule.controller('Ctrl', ['ping', function(ping) {
 *     ping.send();
 *   }]);
 * ```
 */


/**
 * @ngdoc method
 * @name $provide#value
 * @description
 *
 * Register a **value service** with the {@link auto.$injector $injector}, such as a string, a
 * number, an array, an object or a function.  This is short for registering a service where its
 * provider's `$get` property is a factory function that takes no arguments and returns the **value
 * service**.
 *
 * Value services are similar to constant services, except that they cannot be injected into a
 * module configuration function (see {@link angular.Module#config}) but they can be overridden by
 * an Angular
 * {@link auto.$provide#decorator decorator}.
 *
 * @param {string} name The name of the instance.
 * @param {*} value The value.
 * @returns {Object} registered provider instance
 *
 * @example
 * Here are some examples of creating value services.
 * ```js
 *   $provide.value('ADMIN_USER', 'admin');
 *
 *   $provide.value('RoleLookup', { admin: 0, writer: 1, reader: 2 });
 *
 *   $provide.value('halfOf', function(value) {
 *     return value / 2;
 *   });
 * ```
 */


/**
 * @ngdoc method
 * @name $provide#constant
 * @description
 *
 * Register a **constant service**, such as a string, a number, an array, an object or a function,
 * with the {@link auto.$injector $injector}. Unlike {@link auto.$provide#value value} it can be
 * injected into a module configuration function (see {@link angular.Module#config}) and it cannot
 * be overridden by an Angular {@link auto.$provide#decorator decorator}.
 *
 * @param {string} name The name of the constant.
 * @param {*} value The constant value.
 * @returns {Object} registered instance
 *
 * @example
 * Here a some examples of creating constants:
 * ```js
 *   $provide.constant('SHARD_HEIGHT', 306);
 *
 *   $provide.constant('MY_COLOURS', ['red', 'blue', 'grey']);
 *
 *   $provide.constant('double', function(value) {
 *     return value * 2;
 *   });
 * ```
 */


/**
 * @ngdoc method
 * @name $provide#decorator
 * @description
 *
 * Register a **service decorator** with the {@link auto.$injector $injector}. A service decorator
 * intercepts the creation of a service, allowing it to override or modify the behaviour of the
 * service. The object returned by the decorator may be the original service, or a new service
 * object which replaces or wraps and delegates to the original service.
 *
 * @param {string} name The name of the service to decorate.
 * @param {function()} decorator This function will be invoked when the service needs to be
 *    instantiated and should return the decorated service instance. The function is called using
 *    the {@link auto.$injector#invoke injector.invoke} method and is therefore fully injectable.
 *    Local injection arguments:
 *
 *    * `$delegate` - The original service instance, which can be monkey patched, configured,
 *      decorated or delegated to.
 *
 * @example
 * Here we decorate the {@link ng.$log $log} service to convert warnings to errors by intercepting
 * calls to {@link ng.$log#error $log.warn()}.
 * ```js
 *   $provide.decorator('$log', ['$delegate', function($delegate) {
 *     $delegate.warn = $delegate.error;
 *     return $delegate;
 *   }]);
 * ```
 */


function createInjector(modulesToLoad, strictDi) {
  strictDi = (strictDi === true);
  var INSTANTIATING = {},
      providerSuffix = 'Provider',
      path = [],
      loadedModules = new HashMap([], true),
      providerCache = {
        $provide: {
            provider: supportObject(provider),
            factory: supportObject(factory),
            service: supportObject(service),
            value: supportObject(value),
            constant: supportObject(constant),
            decorator: decorator
          }
      },
      providerInjector = (providerCache.$injector =
          createInternalInjector(providerCache, function() {
            throw $injectorMinErr('unpr', "Unknown provider: {0}", path.join(' <- '));
          })),
      instanceCache = {},
      instanceInjector = (instanceCache.$injector =
          createInternalInjector(instanceCache, function(servicename) {
            var provider = providerInjector.get(servicename + providerSuffix);
            return instanceInjector.invoke(provider.$get, provider, undefined, servicename);
          }));


  forEach(loadModules(modulesToLoad), function(fn) { instanceInjector.invoke(fn || noop); });

  return instanceInjector;

  ////////////////////////////////////
  // $provider
  ////////////////////////////////////

  function supportObject(delegate) {
    return function(key, value) {
      if (isObject(key)) {
        forEach(key, reverseParams(delegate));
      } else {
        return delegate(key, value);
      }
    };
  }

  function provider(name, provider_) {
    assertNotHasOwnProperty(name, 'service');
    if (isFunction(provider_) || isArray(provider_)) {
      provider_ = providerInjector.instantiate(provider_);
    }
    if (!provider_.$get) {
      throw $injectorMinErr('pget', "Provider '{0}' must define $get factory method.", name);
    }
    return providerCache[name + providerSuffix] = provider_;
  }

  function enforceReturnValue(name, factory) {
    return function enforcedReturnValue() {
      var result = instanceInjector.invoke(factory, this, undefined, name);
      if (isUndefined(result)) {
        throw $injectorMinErr('undef', "Provider '{0}' must return a value from $get factory method.", name);
      }
      return result;
    };
  }

  function factory(name, factoryFn, enforce) {
    return provider(name, {
      $get: enforce !== false ? enforceReturnValue(name, factoryFn) : factoryFn
    });
  }

  function service(name, constructor) {
    return factory(name, ['$injector', function($injector) {
      return $injector.instantiate(constructor);
    }]);
  }

  function value(name, val) { return factory(name, valueFn(val), false); }

  function constant(name, value) {
    assertNotHasOwnProperty(name, 'constant');
    providerCache[name] = value;
    instanceCache[name] = value;
  }

  function decorator(serviceName, decorFn) {
    var origProvider = providerInjector.get(serviceName + providerSuffix),
        orig$get = origProvider.$get;

    origProvider.$get = function() {
      var origInstance = instanceInjector.invoke(orig$get, origProvider);
      return instanceInjector.invoke(decorFn, null, {$delegate: origInstance});
    };
  }

  ////////////////////////////////////
  // Module Loading
  ////////////////////////////////////
  function loadModules(modulesToLoad) {
    var runBlocks = [], moduleFn;
    forEach(modulesToLoad, function(module) {
      if (loadedModules.get(module)) return;
      loadedModules.put(module, true);

      function runInvokeQueue(queue) {
        var i, ii;
        for (i = 0, ii = queue.length; i < ii; i++) {
          var invokeArgs = queue[i],
              provider = providerInjector.get(invokeArgs[0]);

          provider[invokeArgs[1]].apply(provider, invokeArgs[2]);
        }
      }

      try {
        if (isString(module)) {
          moduleFn = angularModule(module);
          runBlocks = runBlocks.concat(loadModules(moduleFn.requires)).concat(moduleFn._runBlocks);
          runInvokeQueue(moduleFn._invokeQueue);
          runInvokeQueue(moduleFn._configBlocks);
        } else if (isFunction(module)) {
            runBlocks.push(providerInjector.invoke(module));
        } else if (isArray(module)) {
            runBlocks.push(providerInjector.invoke(module));
        } else {
          assertArgFn(module, 'module');
        }
      } catch (e) {
        if (isArray(module)) {
          module = module[module.length - 1];
        }
        if (e.message && e.stack && e.stack.indexOf(e.message) == -1) {
          // Safari & FF's stack traces don't contain error.message content
          // unlike those of Chrome and IE
          // So if stack doesn't contain message, we create a new string that contains both.
          // Since error.stack is read-only in Safari, I'm overriding e and not e.stack here.
          /* jshint -W022 */
          e = e.message + '\n' + e.stack;
        }
        throw $injectorMinErr('modulerr', "Failed to instantiate module {0} due to:\n{1}",
                  module, e.stack || e.message || e);
      }
    });
    return runBlocks;
  }

  ////////////////////////////////////
  // internal Injector
  ////////////////////////////////////

  function createInternalInjector(cache, factory) {

    function getService(serviceName) {
      if (cache.hasOwnProperty(serviceName)) {
        if (cache[serviceName] === INSTANTIATING) {
          throw $injectorMinErr('cdep', 'Circular dependency found: {0}',
                    serviceName + ' <- ' + path.join(' <- '));
        }
        return cache[serviceName];
      } else {
        try {
          path.unshift(serviceName);
          cache[serviceName] = INSTANTIATING;
          return cache[serviceName] = factory(serviceName);
        } catch (err) {
          if (cache[serviceName] === INSTANTIATING) {
            delete cache[serviceName];
          }
          throw err;
        } finally {
          path.shift();
        }
      }
    }

    function invoke(fn, self, locals, serviceName) {
      if (typeof locals === 'string') {
        serviceName = locals;
        locals = null;
      }

      var args = [],
          $inject = annotate(fn, strictDi, serviceName),
          length, i,
          key;

      for (i = 0, length = $inject.length; i < length; i++) {
        key = $inject[i];
        if (typeof key !== 'string') {
          throw $injectorMinErr('itkn',
                  'Incorrect injection token! Expected service name as string, got {0}', key);
        }
        args.push(
          locals && locals.hasOwnProperty(key)
          ? locals[key]
          : getService(key)
        );
      }
      if (isArray(fn)) {
        fn = fn[length];
      }

      // http://jsperf.com/angularjs-invoke-apply-vs-switch
      // #5388
      return fn.apply(self, args);
    }

    function instantiate(Type, locals, serviceName) {
      // Check if Type is annotated and use just the given function at n-1 as parameter
      // e.g. someModule.factory('greeter', ['$window', function(renamed$window) {}]);
      // Object creation: http://jsperf.com/create-constructor/2
      var instance = Object.create((isArray(Type) ? Type[Type.length - 1] : Type).prototype);
      var returnedValue = invoke(Type, instance, locals, serviceName);

      return isObject(returnedValue) || isFunction(returnedValue) ? returnedValue : instance;
    }

    return {
      invoke: invoke,
      instantiate: instantiate,
      get: getService,
      annotate: annotate,
      has: function(name) {
        return providerCache.hasOwnProperty(name + providerSuffix) || cache.hasOwnProperty(name);
      }
    };
  }
}

createInjector.$$annotate = annotate;