feat(injector): initial implementaion of dynamic injector

modules/di/src/annotations.js

@@ -0,0 +1,7 @@
+//TODO: vsavkin: uncomment once const constructor are supported
+//export class Inject {
+//  @CONST
+//  constructor(token){
+//    this.token = token;
+//  }
+//}

modules/di/src/binding.js

@@ -0,0 +1,64 @@
+import {Type} from 'facade/lang';
+import {List, MapWrapper, ListWrapper} from 'facade/collection';
+import {Reflector} from 'facade/di/reflector';
+import {Key} from './key';
+
+export class Binding {
+  constructor(key:Key, factory:Function, dependencies:List, async) {
+    this.key = key;
+    this.factory = factory;
+    this.dependencies = dependencies;
+    this.async = async;
+  }
+}
+
+export function bind(token):BindingBuilder {
+  return new BindingBuilder(token);
+}
+
+export class BindingBuilder {
+  constructor(token) {
+    this.token = token;
+    this.reflector = new Reflector();
+  }
+
+  toClass(type:Type):Binding {
+    return new Binding(
+      Key.get(this.token),
+      this.reflector.factoryFor(type),
+      this._wrapKeys(this.reflector.dependencies(type)),
+      false
+    );
+  }
+
+  toValue(value):Binding {
+    return new Binding(
+      Key.get(this.token),
+      (_) => value,
+      [],
+      false
+    );
+  }
+
+  toFactory(dependencies:List, factoryFunction:Function):Binding {
+    return new Binding(
+      Key.get(this.token),
+      this.reflector.convertToFactory(factoryFunction),
+      this._wrapKeys(dependencies),
+      false
+    );
+  }
+
+  toAsyncFactory(dependencies:List, factoryFunction:Function):Binding {
+    return new Binding(
+      Key.get(this.token),
+      this.reflector.convertToFactory(factoryFunction),
+      this._wrapKeys(dependencies),
+      true
+    );
+  }
+
+  _wrapKeys(deps:List) {
+    return ListWrapper.map(deps, (t) => Key.get(t));
+  }
+}

modules/di/src/di.js

@@ -1 +1,5 @@
-export * from './module';
+export * from './injector';
+export * from './binding';
+export * from './key';
+export * from './module';
+export {Inject} from 'facade/di/reflector';

modules/di/src/exceptions.js

@@ -0,0 +1,52 @@
+import {ListWrapper, List} from 'facade/collection';
+import {humanize} from 'facade/lang';
+
+function constructResolvingPath(keys: List) {
+  if (keys.length > 1) {
+    var tokenStrs = ListWrapper.map(keys, (k) => humanize(k.token));
+    return " (" + tokenStrs.join(' -> ') + ")";
+  } else {
+    return "";
+  }
+}
+
+export class NoProviderError extends Error {
+  constructor(keys:List){
+    this.message = this._constructResolvingMessage(keys);
+  }
+
+  _constructResolvingMessage(keys:List) {
+    var last = humanize(ListWrapper.last(keys).token);
+    return `No provider for ${last}!${constructResolvingPath(keys)}`;
+  }
+
+  toString() {
+    return this.message;
+  }
+}
+
+export class AsyncProviderError extends Error {
+  constructor(keys:List){
+    this.message = this._constructResolvingMessage(keys);
+  }
+
+  _constructResolvingMessage(keys:List) {
+    var last = humanize(ListWrapper.last(keys).token);
+    return `Cannot instantiate ${last} synchronously. ` +
+      `It is provided as a future!${constructResolvingPath(keys)}`;
+  }
+
+  toString() {
+    return this.message;
+  }
+}
+
+export class InvalidBindingError extends Error {
+  constructor(binding){
+    this.message = `Invalid binding ${binding}`;
+  }
+
+  toString() {
+    return this.message;
+  }
+}

modules/di/src/injector.js

@@ -0,0 +1,133 @@
+import {Map, List, MapWrapper, ListWrapper} from 'facade/collection';
+import {Binding, BindingBuilder, bind} from './binding';
+import {NoProviderError, InvalidBindingError, AsyncProviderError} from './exceptions';
+import {Type, isPresent, isBlank} from 'facade/lang';
+import {Future, FutureWrapper} from 'facade/async';
+import {Key} from './key';
+
+export class Injector {
+  constructor(bindings:List) {
+    var flatten = _flattenBindings(bindings);
+    this._bindings = this._createListOfBindings(flatten);
+    this._instances = this._createInstances();
+    this._parent = null; //TODO: vsavkin make a parameter
+  }
+
+  _createListOfBindings(flattenBindings):List {
+    var bindings = ListWrapper.createFixedSize(Key.numberOfKeys() + 1);
+    MapWrapper.forEach(flattenBindings, (keyId, v) => bindings[keyId] = v);
+    return bindings;
+  }
+
+  _createInstances():List {
+    return ListWrapper.createFixedSize(Key.numberOfKeys() + 1);
+  }
+
+  get(token) {
+    return this.getByKey(Key.get(token));
+  }
+
+  asyncGet(token) {
+    return this.asyncGetByKey(Key.get(token));
+  }
+
+  getByKey(key:Key) {
+    return this._getByKey(key, [], false);
+  }
+
+  asyncGetByKey(key:Key) {
+    return this._getByKey(key, [], true);
+  }
+
+  _getByKey(key:Key, resolving:List, async) {
+    var keyId = key.id;
+    //TODO: vsavkin: use LinkedList to remove clone
+    resolving = ListWrapper.clone(resolving)
+    ListWrapper.push(resolving, key);
+
+    if (key.token === Injector) return this._injector(async);
+
+    var instance = this._get(this._instances, keyId);
+    if (isPresent(instance)) return instance;
+
+    var binding = this._get(this._bindings, keyId);
+
+    if (isPresent(binding)) {
+      return this._instantiate(key, binding, resolving, async);
+    }
+
+    if (isPresent(this._parent)) {
+      return this._parent._getByKey(key, resolving, async);
+    }
+
+    throw new NoProviderError(resolving);
+  }
+
+  createChild(bindings:List):Injector {
+    var inj = new Injector(bindings);
+    inj._parent = this; //TODO: vsavkin: change it when optional parameters are working
+    return inj;
+  }
+
+  _injector(async){
+    return async ? FutureWrapper.value(this) : this;
+  }
+
+  _get(list:List, index){
+    if (list.length <= index) return null;
+    return ListWrapper.get(list, index);
+  }
+
+  _instantiate(key:Key, binding:Binding, resolving:List, async) {
+    if (binding.async && !async) {
+      throw new AsyncProviderError(resolving);
+    }
+
+    if (async) {
+      return this._instantiateAsync(key, binding, resolving, async);
+    } else {
+      return this._instantiateSync(key, binding, resolving, async);
+    }
+  }
+
+  _instantiateSync(key:Key, binding:Binding, resolving:List, async) {
+    var deps = ListWrapper.map(binding.dependencies, d => this._getByKey(d, resolving, false));
+    var instance = binding.factory(deps);
+    ListWrapper.set(this._instances, key.id, instance);
+    if (!binding.async && async) {
+      return FutureWrapper.value(instance);
+    }
+    return instance;
+  }
+
+  _instantiateAsync(key:Key, binding:Binding, resolving:List, async):Future {
+    var instances = this._createInstances();
+    var futures = ListWrapper.map(binding.dependencies, d => this._getByKey(d, resolving, true));
+    return FutureWrapper.wait(futures).
+      then(binding.factory).
+      then(function(instance) {
+        ListWrapper.set(instances, key.id, instance);
+        return instance
+      });
+  }
+}
+
+function _flattenBindings(bindings:List) {
+  var res = {};
+  ListWrapper.forEach(bindings, function (b){
+    if (b instanceof Binding) {
+      MapWrapper.set(res, b.key.id, b);
+
+    } else if (b instanceof Type) {
+      var s = bind(b).toClass(b);
+      MapWrapper.set(res, s.key.id, s);
+
+    } else if (b instanceof BindingBuilder) {
+      throw new InvalidBindingError(b.token);
+
+    } else {
+      throw new InvalidBindingError(b);
+    }
+  });
+  return res;
+}

modules/di/src/key.js

@@ -1,3 +1,25 @@
-export class Key {
+import {MapWrapper} from 'facade/collection';
 
+var _allKeys = {};
+var _id = 0;
+
+export class Key {
+  constructor(token, id) {
+    this.token = token;
+    this.id = id;
+  }
+
+  static get(token) {
+    if (MapWrapper.contains(_allKeys, token)) {
+      return MapWrapper.get(_allKeys, token)
+    }
+
+    var newKey = new Key(token, ++_id);
+    MapWrapper.set(_allKeys, token, newKey);
+    return newKey;
+  }
+
+  static numberOfKeys() {
+    return _id;
+  }
 }

modules/di/src/module.js

@@ -1,26 +1 @@
-import {FIELD} from 'facade/lang';
-import {Type} from 'facade/lang';
-import {Map, MapWrapper} from 'facade/collection';
-import {Key} from './key';
-
-/// becouse we need to know when toValue was not set.
-/// (it could be that toValue is set to null or undefined in js)
-var _UNDEFINED = {}
-
-export class Module {
-
-  @FIELD('final bindings:Map<Key, Binding>')
-  constructor(){
-    this.bindings = new MapWrapper();
-  }
-
-  bind(type:Type,
-      {toValue/*=_UNDEFINED*/, toFactory, toImplementation, inject, toInstanceOf, withAnnotation}/*:
-        {toFactory:Function, toImplementation: Type, inject: Array, toInstanceOf:Type}*/) {}
-
-  bindByKey(key:Key,
-      {toValue/*=_UNDEFINED*/, toFactory, toImplementation, inject, toInstanceOf}/*:
-        {toFactory:Function, toImplementation: Type, inject: Array, toInstanceOf:Type}*/) {}
-
-  install(module:Module) {}
-}
+export class Module {}

modules/di/test/di/async_spec.js

@@ -0,0 +1,76 @@
+import {ddescribe, describe, it, iit, xit, expect, beforeEach} from 'test_lib/test_lib';
+import {Injector, Inject, bind, Key} from 'di/di';
+import {Future, FutureWrapper} from 'facade/async';
+
+class UserList {}
+
+function fetchUsers() {
+  return FutureWrapper.value(new UserList());
+}
+
+class SynchronousUserList {}
+
+
+class UserController {
+  constructor(list:UserList) {
+    this.list = list;
+  }
+}
+
+export function main () {
+  describe("async injection", function () {
+    it('should return a future', function() {
+      var injector = new Injector([
+        bind(UserList).toAsyncFactory([], fetchUsers)
+      ]);
+      var p = injector.asyncGet(UserList);
+      expect(p).toBeFuture();
+    });
+
+    it('should throw when instantiating async provider synchronously', function() {
+      var injector = new Injector([
+        bind(UserList).toAsyncFactory([], fetchUsers)
+      ]);
+
+      expect(() => injector.get(UserList))
+        .toThrowError('Cannot instantiate UserList synchronously. It is provided as a future!');
+    });
+
+    it('should return a future even if the provider is sync', function() {
+      var injector = new Injector([
+        SynchronousUserList
+      ]);
+      var p = injector.asyncGet(SynchronousUserList);
+      expect(p).toBeFuture();
+    });
+
+    it('should provide itself', function() {
+      var injector = new Injector([]);
+      var p = injector.asyncGet(Injector);
+      expect(p).toBeFuture();
+    });
+
+    it('should return a future when a dependency is async', function(done) {
+      var injector = new Injector([
+        bind(UserList).toAsyncFactory([], fetchUsers),
+        UserController
+      ]);
+
+      injector.asyncGet(UserController).then(function(userController) {
+        expect(userController).toBeAnInstanceOf(UserController);
+        expect(userController.list).toBeAnInstanceOf(UserList);
+        done();
+      });
+    });
+
+    it('should throw when a dependency is async', function() {
+      var injector = new Injector([
+        bind(UserList).toAsyncFactory([], fetchUsers),
+        UserController
+      ]);
+
+      expect(() => injector.get(UserController))
+        .toThrowError('Cannot instantiate UserList synchronously. It is provided as a future! (UserController -> UserList)');
+    });
+  });
+}

modules/di/test/di/injector_spec.js

@@ -0,0 +1,144 @@
+import {describe, it, expect, beforeEach} from 'test_lib/test_lib';
+import {Injector, Inject, bind} from 'di/di';
+
+class Engine {}
+class Dashboard {}
+class TurboEngine extends Engine{}
+
+class Car {
+  constructor(engine:Engine) {
+    this.engine = engine;
+  }
+}
+
+class CarWithDashboard {
+  constructor(engine:Engine, dashboard:Dashboard) {
+    this.engine = engine;
+    this.dashboard = dashboard;
+  }
+}
+
+class SportsCar extends Car {
+  constructor(engine:Engine) {
+    super(engine);
+  }
+}
+
+class CarWithInject {
+  constructor(@Inject(TurboEngine) engine:Engine) {
+    this.engine = engine;
+  }
+}
+
+export function main() {
+  describe('injector', function() {
+    it('should instantiate a class without dependencies', function() {
+      var injector = new Injector([Engine]);
+      var engine = injector.get(Engine);
+
+      expect(engine).toBeAnInstanceOf(Engine);
+    });
+
+    it('should resolve dependencies based on type information', function() {
+      var injector = new Injector([Engine, Car]);
+      var car = injector.get(Car);
+
+      expect(car).toBeAnInstanceOf(Car);
+      expect(car.engine).toBeAnInstanceOf(Engine);
+    });
+
+    it('should resolve dependencies based on @Inject annotation', function() {
+      var injector = new Injector([TurboEngine, Engine, CarWithInject]);
+      var car = injector.get(CarWithInject);
+
+      expect(car).toBeAnInstanceOf(CarWithInject);
+      expect(car.engine).toBeAnInstanceOf(TurboEngine);
+    });
+
+    it('should cache instances', function() {
+      var injector = new Injector([Engine]);
+
+      var e1 = injector.get(Engine);
+      var e2 = injector.get(Engine);
+
+      expect(e1).toBe(e2);
+    });
+
+    it('should bind to a value', function() {
+      var injector = new Injector([
+        bind(Engine).toValue("fake engine")
+      ]);
+
+      var engine = injector.get(Engine);
+      expect(engine).toEqual("fake engine");
+    });
+
+    it('should bind to a factory', function() {
+      var injector = new Injector([
+        Engine,
+        bind(Car).toFactory([Engine], (e) => new SportsCar(e))
+      ]);
+
+      var car = injector.get(Car);
+      expect(car).toBeAnInstanceOf(SportsCar);
+      expect(car.engine).toBeAnInstanceOf(Engine);
+    });
+
+    it('should use non-type tokens', function() {
+      var injector = new Injector([
+        bind('token').toValue('value')
+      ]);
+
+      expect(injector.get('token')).toEqual('value');
+    });
+
+    it('should throw when given invalid bindings', function() {
+      expect(() => new Injector(["blah"])).toThrowError('Invalid binding blah');
+      expect(() => new Injector([bind("blah")])).toThrowError('Invalid binding blah');
+    });
+
+    describe("child", function () {
+      it('should load instances from parent injector', function() {
+        var parent = new Injector([Engine]);
+        var child = parent.createChild([]);
+
+        var engineFromParent = parent.get(Engine);
+        var engineFromChild = child.get(Engine);
+
+        expect(engineFromChild).toBe(engineFromParent);
+      });
+
+      it('should create new instance in a child injector', function() {
+        var parent = new Injector([Engine]);
+        var child = parent.createChild([
+          bind(Engine).toClass(TurboEngine)
+        ]);
+
+        var engineFromParent = parent.get(Engine);
+        var engineFromChild = child.get(Engine);
+
+        expect(engineFromParent).not.toBe(engineFromChild);
+        expect(engineFromChild).toBeAnInstanceOf(TurboEngine);
+      });
+    });
+
+    it('should provide itself', function() {
+      var parent = new Injector([]);
+      var child = parent.createChild([]);
+
+      expect(child.get(Injector)).toBe(child);
+    });
+
+    it('should throw when no provider defined', function() {
+      var injector = new Injector([]);
+      expect(() => injector.get('NonExisting')).toThrowError('No provider for NonExisting!');
+    });
+
+    it('should show the full path when no provider', function() {
+      var injector = new Injector([CarWithDashboard, Engine]);
+
+      expect(() => injector.get(CarWithDashboard)).
+        toThrowError('No provider for Dashboard! (CarWithDashboard -> Dashboard)');
+    });
+  });
+}

modules/di/test/di/key_spec.js

@@ -0,0 +1,14 @@
+import {describe, it, expect} from 'test_lib/test_lib';
+import {Key} from 'di/di';
+
+export function main () {
+  describe("key", function () {
+    it('should be equal to another key if type is the same', function () {
+      expect(Key.get('car')).toBe(Key.get('car'));
+    });
+
+    it('should not be equal to another key if types are different', function () {
+      expect(Key.get('car')).not.toBe(Key.get('porsche'));
+    });
+  });
+}