Initializes _data in constructor

reflectable/lib/src/mirrors_unimpl.dart

Index: reflectable/lib/src/mirrors_unimpl.dart
diff --git a/reflectable/lib/src/mirrors_unimpl.dart b/reflectable/lib/src/mirrors_unimpl.dart
index 130c6b31fa07c31b3f9ae0da8b63f887f3504329..7dc5e65875808bb0a722362ea110ab6ed32f16a4 100644
--- a/reflectable/lib/src/mirrors_unimpl.dart
+++ b/reflectable/lib/src/mirrors_unimpl.dart
@@ -104,27 +104,24 @@ Map<Reflectable, ReflectorData> data =
         "Did you forget to add the main file to the "
         "reflectable transformer's entry_points in pubspec.yaml?");
 
-abstract class _DataCaching {
-  // TODO(eernst) clarify: When we have some substantial pieces of code using
-  // reflectable, perform some experiments to detect how useful it is to have
-  // this kind of caching.
+abstract class _DataCachingMirror {
+  /// The reflector which represents the mirror system that this
+  /// mirror belongs to.
+  final ReflectableImpl _reflector;
 
-  ReflectorData _dataCache;
-  ReflectableImpl get _reflector;
+  /// Reflector data associated with this mirror.
+  final ReflectorData _data;
 
-  ReflectorData get _data {
-    if (_dataCache == null) {
-      _dataCache = data[_reflector];
-    }
-    return _dataCache;
-  }
+  _DataCachingMirror(ReflectableImpl reflector)
+      : _reflector = reflector,
+        _data = data[reflector];
 }
 
-class _InstanceMirrorImpl extends _DataCaching implements InstanceMirror {
-  final ReflectableImpl _reflector;
+class _InstanceMirrorImpl extends _DataCachingMirror implements InstanceMirror {
   final Object reflectee;
 
-  _InstanceMirrorImpl(this.reflectee, this._reflector) {
+  _InstanceMirrorImpl(this.reflectee, ReflectableImpl reflector)
+      : super(reflector) {
     _type = _data.classMirrorForType(reflectee.runtimeType);
     if (_type == null) {
       throw new NoSuchCapabilityError(
@@ -226,11 +223,7 @@ MethodMirror _variableToSetterMirror(VariableMirrorImpl variableMirror) {
       []);
 }
 
-class ClassMirrorImpl extends _DataCaching implements ClassMirror {
-  /// The reflector which represents the mirror system that this
-  /// mirror belongs to.
-  final ReflectableImpl _reflector;
-
+class ClassMirrorImpl extends _DataCachingMirror implements ClassMirror {
   /// The index of this mirror in the [ReflectorData.classMirrors] table.
   /// Also this is the index of the Type of the reflected class in
   /// [ReflectorData.types].
@@ -263,7 +256,7 @@ class ClassMirrorImpl extends _DataCaching implements ClassMirror {
       this.simpleName,
       this.qualifiedName,
       this._classIndex,
-      this._reflector,
+      ReflectableImpl reflector,
       this._declarationIndices,
       this._instanceMemberIndices,
       this._superclassIndex,
@@ -272,7 +265,8 @@ class ClassMirrorImpl extends _DataCaching implements ClassMirror {
       this.constructors,
       metadata)
       : _metadata =
-            (metadata == null) ? null : new UnmodifiableListView(metadata);
+            (metadata == null) ? null : new UnmodifiableListView(metadata),
+        super(reflector);
 
   ClassMirror get superclass {
     if (_superclassIndex == null) return null;
@@ -452,7 +446,7 @@ class ClassMirrorImpl extends _DataCaching implements ClassMirror {
   // operations.
 }
 
-class MethodMirrorImpl extends _DataCaching implements MethodMirror {
+class MethodMirrorImpl extends _DataCachingMirror implements MethodMirror {
   /// An encoding of the attributes and kind of this mirror.
   final int _descriptor;
 
@@ -466,18 +460,16 @@ class MethodMirrorImpl extends _DataCaching implements MethodMirror {
   /// of this method.
   final List<int> _parameterIndices;
 
-  /// The [Reflectable] associated with this mirror.
-  final ReflectableImpl _reflector;
-
   /// A cache of the metadata of the mirrored method. The empty list means
   /// no metadata, null means that [_reflector] does not have
   /// [metadataCapability].
   final List<Object> _metadata;
 
   MethodMirrorImpl(this._name, this._descriptor, this._ownerIndex,
-      this._parameterIndices, this._reflector, List<Object> metadata)
+      this._parameterIndices, ReflectableImpl reflector, List<Object> metadata)
       : _metadata =
-            (metadata == null) ? null : new UnmodifiableListView(metadata);
+            (metadata == null) ? null : new UnmodifiableListView(metadata),
+        super(reflector);
 
   int get kind => constants.kindFromEncoding(_descriptor);
 
@@ -569,18 +561,18 @@ class MethodMirrorImpl extends _DataCaching implements MethodMirror {
   String toString() => "MethodMirror($_name)";
 }
 
-abstract class VariableMirrorBase extends _DataCaching
+abstract class VariableMirrorBase extends _DataCachingMirror
     implements VariableMirror {
   final String _name;
   final int _descriptor;
   final int _ownerIndex;
-  final ReflectableImpl _reflector;
   final List<Object> _metadata;
 
   VariableMirrorBase(this._name, this._descriptor, this._ownerIndex,
-      this._reflector, List<Object> metadata)
+      ReflectableImpl reflector, List<Object> metadata)
       : _metadata =
-            (metadata == null) ? null : new UnmodifiableListView(metadata);
+            (metadata == null) ? null : new UnmodifiableListView(metadata),
+        super(reflector);
 
   int get kind => constants.kindFromEncoding(_descriptor);