refactor(injector): change reflector to collect the resolving path only when an error occurs

modules/di/src/exceptions.js

@@ -1,23 +1,27 @@
 import {ListWrapper, List} from 'facade/collection';
 import {stringify} from 'facade/lang';
+import {Key} from './key';
 
 function constructResolvingPath(keys: List) {
   if (keys.length > 1) {
-    var tokenStrs = ListWrapper.map(keys, (k) => stringify(k.token));
+    var reversed = ListWrapper.reversed(keys);
+    var tokenStrs = ListWrapper.map(reversed, (k) => stringify(k.token));
     return " (" + tokenStrs.join(' -> ') + ")";
   } else {
     return "";
   }
 }
 
-export class NoProviderError extends Error {
-  constructor(keys:List){
-    this.message = this._constructResolvingMessage(keys);
+export class ProviderError extends Error {
+  constructor(key:Key, constructResolvingMessage:Function){
+    this.keys = [key];
+    this.constructResolvingMessage = constructResolvingMessage;
+    this.message = this.constructResolvingMessage(this.keys);
   }
 
-  _constructResolvingMessage(keys:List) {
-    var last = stringify(ListWrapper.last(keys).token);
-    return `No provider for ${last}!${constructResolvingPath(keys)}`;
+  addKey(key: Key) {
+    ListWrapper.push(this.keys, key);
+    this.message = this.constructResolvingMessage(this.keys);
   }
 
   toString() {
@@ -25,19 +29,22 @@ export class NoProviderError extends Error {
   }
 }
 
-export class AsyncProviderError extends Error {
-  constructor(keys:List){
-    this.message = this._constructResolvingMessage(keys);
+export class NoProviderError extends ProviderError {
+  constructor(key:Key){
+    super(key, function(keys:List) {
+      var first = stringify(ListWrapper.first(keys).token);
+      return `No provider for ${first}!${constructResolvingPath(keys)}`;
+    });
   }
+}
 
-  _constructResolvingMessage(keys:List) {
-    var last = stringify(ListWrapper.last(keys).token);
-    return `Cannot instantiate ${last} synchronously. ` +
-      `It is provided as a future!${constructResolvingPath(keys)}`;
-  }
-
-  toString() {
-    return this.message;
+export class AsyncProviderError extends ProviderError {
+  constructor(key:Key){
+    super(key, function(keys:List) {
+      var first = stringify(ListWrapper.first(keys).token);
+      return `Cannot instantiate ${first} synchronously. ` +
+        `It is provided as a future!${constructResolvingPath(keys)}`;
+    });
   }
 }
 

modules/di/src/injector.js

@@ -1,6 +1,6 @@
 import {Map, List, MapWrapper, ListWrapper} from 'facade/collection';
 import {Binding, BindingBuilder, bind} from './binding';
-import {NoProviderError, InvalidBindingError, AsyncProviderError} from './exceptions';
+import {ProviderError, NoProviderError, InvalidBindingError, AsyncProviderError} from './exceptions';
 import {Type, isPresent, isBlank} from 'facade/lang';
 import {Future, FutureWrapper} from 'facade/async';
 import {Key} from './key';
@@ -32,19 +32,15 @@ export class Injector {
   }
 
   getByKey(key:Key) {
-    return this._getByKey(key, [], false);
+    return this._getByKey(key, false);
   }
 
   asyncGetByKey(key:Key) {
-    return this._getByKey(key, [], true);
+    return this._getByKey(key, true);
   }
 
-  _getByKey(key:Key, resolving:List, async) {
+  _getByKey(key:Key, 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);
@@ -53,14 +49,14 @@ export class Injector {
     var binding = this._get(this._bindings, keyId);
 
     if (isPresent(binding)) {
-      return this._instantiate(key, binding, resolving, async);
+      return this._instantiate(key, binding, async);
     }
 
     if (isPresent(this._parent)) {
-      return this._parent._getByKey(key, resolving, async);
+      return this._parent._getByKey(key, async);
     }
 
-    throw new NoProviderError(resolving);
+    throw new NoProviderError(key);
   }
 
   createChild(bindings:List):Injector {
@@ -78,31 +74,37 @@ export class Injector {
     return ListWrapper.get(list, index);
   }
 
-  _instantiate(key:Key, binding:Binding, resolving:List, async) {
+  _instantiate(key:Key, binding:Binding, async) {
     if (binding.async && !async) {
-      throw new AsyncProviderError(resolving);
+      throw new AsyncProviderError(key);
     }
 
     if (async) {
-      return this._instantiateAsync(key, binding, resolving, async);
+      return this._instantiateAsync(key, binding, async);
     } else {
-      return this._instantiateSync(key, binding, resolving, async);
+      return this._instantiateSync(key, binding, 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);
+  _instantiateSync(key:Key, binding:Binding, async) {
+    try {
+      var deps = ListWrapper.map(binding.dependencies, d => this._getByKey(d, false));
+      var instance = binding.factory(deps);
+      ListWrapper.set(this._instances, key.id, instance);
+      if (!binding.async && async) {
+        return FutureWrapper.value(instance);
+      }
+      return instance;
+
+    } catch (e) {
+      if (e instanceof ProviderError) e.addKey(key);
+      throw e;
     }
-    return instance;
   }
 
-  _instantiateAsync(key:Key, binding:Binding, resolving:List, async):Future {
+  _instantiateAsync(key:Key, binding:Binding, async):Future {
     var instances = this._createInstances();
-    var futures = ListWrapper.map(binding.dependencies, d => this._getByKey(d, resolving, true));
+    var futures = ListWrapper.map(binding.dependencies, d => this._getByKey(d, true));
     return FutureWrapper.wait(futures).
       then(binding.factory).
       then(function(instance) {

modules/di/test/di/async_spec.js

@@ -72,5 +72,7 @@ export function main () {
       expect(() => injector.get(UserController))
         .toThrowError('Cannot instantiate UserList synchronously. It is provided as a future! (UserController -> UserList)');
     });
+
+    // resolve exceptions and async
   });
 }

modules/di/test/di/injector_spec.js

@@ -2,7 +2,10 @@ import {describe, it, expect, beforeEach} from 'test_lib/test_lib';
 import {Injector, Inject, bind} from 'di/di';
 
 class Engine {}
-class Dashboard {}
+class DashboardSoftware {}
+class Dashboard {
+  constructor(software: DashboardSoftware){}
+}
 class TurboEngine extends Engine{}
 
 class Car {
@@ -135,10 +138,9 @@ export function main() {
     });
 
     it('should show the full path when no provider', function() {
-      var injector = new Injector([CarWithDashboard, Engine]);
-
+      var injector = new Injector([CarWithDashboard, Engine, Dashboard]);
       expect(() => injector.get(CarWithDashboard)).
-        toThrowError('No provider for Dashboard! (CarWithDashboard -> Dashboard)');
+        toThrowError('No provider for DashboardSoftware! (CarWithDashboard -> Dashboard -> DashboardSoftware)');
     });
   });
 }

modules/facade/src/collection.dart

@@ -24,9 +24,15 @@ class ListWrapper {
   static forEach(list, fn) {
     list.forEach(fn);
   }
-  static last(list) {
+  static first(List list) {
+    return list.first;
+  }
+  static last(List list) {
     return list.last;
   }
+  static reversed(List list) {
+    return list.reversed;
+  }
   static void push(List l, e) { l.add(e); }
 }
 

modules/facade/src/collection.es6

@@ -34,10 +34,18 @@ export class ListWrapper {
   static push(array, el) {
     array.push(el);
   }
+  static first(array) {
+    if (!array) return null;
+    return array[0];
+  }
   static last(array) {
     if (!array || array.length == 0) return null;
     return array[array.length - 1];
   }
+  static reversed(array) {
+    var a = ListWrapper.clone(array);
+    return a.reverse();
+  }
 }
 
 export class SetWrapper {