Adding package:smoke. This CL includes the intial APIs, a mirror-based

pkg/smoke/lib/mirrors.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// Implementation of the smoke services using mirrors.
+library smoke.mirrors;
+
+import 'dart:mirrors';
+import 'package:smoke/smoke.dart';
+import 'package:logging/logging.dart';
+import 'src/common.dart';
+
+/// Set up the smoke package to use a mirror-based implementation. To tune what
+/// is preserved by `dart:mirrors`, use a @MirrorsUsed annotation and include
+/// 'smoke.mirrors' in your override arguments.
+useMirrors() {
+  configure(new ReflectiveObjectAccessorService(),
+      new ReflectiveTypeInspectorService(),
+      new ReflectiveSymbolConverterService());
+}
+
+var _logger = new Logger('smoke.mirrors');
+
+
+/// Implements [ObjectAccessorService] using mirrors.
+class ReflectiveObjectAccessorService implements ObjectAccessorService {
+  read(Object object, Symbol name) {
+    var decl = getDeclaration(object.runtimeType, name);
+    if (decl != null && decl.isMethod) {
+      // TODO(sigmund,jmesserly): remove this once dartbug.com/13002 is fixed.
+      return new _MethodClosure(object, name);
+    } else {
+      return reflect(object).getField(name).reflectee;
+    }
+  }
+
+  void write(Object object, Symbol name, value) {
+    reflect(object).setField(name, value);
+  }
+
+  invoke(receiver, Symbol methodName, List args,
+      {Map namedArgs, bool adjust: false}) {
+    var receiverMirror;
+    var method;
+    if (receiver is Type) {
+      receiverMirror = reflectType(receiver);
+      method = receiverMirror.declarations[methodName];
+    } else {
+      receiverMirror = reflect(receiver);
+      method = _findMethod(receiverMirror.type, methodName);
+    }
+    if (method != null && adjust) {
+      var required = 0;
+      var optional = 0;
+      for (var p in method.parameters) {
+        if (p.isOptional) {
+          if (!p.isNamed) optional++;
+        } else {
+          required++;
+        }
+      }
+      args = adjustList(args, required, required + optional);
+    }
+    return receiverMirror.invoke(methodName, args, namedArgs).reflectee;
+  }
+}
+
+/// Implements [TypeInspectorService] using mirrors.
+class ReflectiveTypeInspectorService implements TypeInspectorService {
+  bool hasGetter(Type type, Symbol name) {
+    var mirror = reflectType(type);
+    if (mirror is! ClassMirror) return false;
+    while (mirror != _objectType) {
+      final members = mirror.declarations;
+      if (members.containsKey(name)) return true;
+      mirror = _safeSuperclass(mirror);
+    }
+    return false;
+  }
+
+  bool hasSetter(Type type, Symbol name) {
+    var mirror = reflectType(type);
+    if (mirror is! ClassMirror) return false;
+    var setterName = _setterName(name);
+    while (mirror != _objectType) {
+      final members = mirror.declarations;
+      var declaration = members[name];
+      if (declaration is VariableMirror && !declaration.isFinal) return true;
+      if (members.containsKey(setterName)) return true;
+      mirror = _safeSuperclass(mirror);
+    }
+    return false;
+  }
+
+  bool hasInstanceMethod(Type type, Symbol name) {
+    var mirror = reflectType(type);
+    if (mirror is! ClassMirror) return false;
+    while (mirror != _objectType) {
+      final m = mirror.declarations[name];
+      if (m is MethodMirror && m.isRegularMethod && !m.isStatic) return true;
+      mirror = _safeSuperclass(mirror);
+    }
+    return false;
+  }
+
+  bool hasStaticMethod(Type type, Symbol name) {
+    var mirror = reflectType(type);
+    if (mirror is! ClassMirror) return false;
+    final m = mirror.declarations[name];
+    return m is MethodMirror && m.isRegularMethod && m.isStatic;
+  }
+
+  Declaration getDeclaration(Type type, Symbol name) {
+    var mirror = reflectType(type);
+    if (mirror is! ClassMirror) return null;
+
+    var declaration;
+    while (mirror != _objectType) {
+      final members = mirror.declarations;
+      if (members.containsKey(name)) {
+        declaration = members[name];
+        break;
+      }
+      mirror = _safeSuperclass(mirror);
+    }
+    if (declaration == null) {
+      _logger.severe("declaration doesn't exists ($type.$name).");
+      return null;
+    }
+    return new _MirrorDeclaration(mirror, declaration);
+  }
+
+  List<Declaration> query(Type type, QueryOptions options) {
+    var mirror = reflectType(type);
+    if (mirror is! ClassMirror) return null;
+    return _query(mirror, options);
+  }
+
+  List<Declaration> _query(ClassMirror cls, QueryOptions options) {
+    var result = (!options.includeInherited || cls.superclass == _objectType)
+        ? [] : _query(cls.superclass, options);
+    for (var member in cls.declarations.values) {
+      if (member is! VariableMirror && member is! MethodMirror) continue;
+      if (member.isStatic || member.isPrivate) continue;
+      var name = member.simpleName;
+      bool isMethod = false;
+      if (member is VariableMirror) {
+        if (!options.includeProperties) continue;
+        if (options.excludeFinal && member.isFinal) continue;
+      }
+
+      // TODO(sigmund): what if we have a setter but no getter?
+      if (member is MethodMirror && member.isSetter) continue;
+      if (member is MethodMirror && member.isConstructor) continue;
+
+      if (member is MethodMirror && member.isGetter) {
+        if (!options.includeProperties) continue;
+        if (options.excludeFinal && !_hasSetter(cls, member)) continue;
+      }
+
+      if (member is MethodMirror && member.isRegularMethod) {
+        if (!options.includeMethods) continue;
+        isMethod = true;
+      }
+
+      var annotations =
+          member.metadata.map((m) => m.reflectee).toList();
+      if (options.withAnnotations != null &&
+          !matchesAnnotation(annotations, options.withAnnotations)) {
+        continue;
+      }
+
+      // TODO(sigmund): should we cache parts of this declaration so we don't
+      // compute them twice?  For example, this chould be `new Declaration(name,
+      // type, ...)` and we could reuse what we computed above to implement the
+      // query filtering.  Note, when I tried to eagerly compute everything, I
+      // run into trouble with type (`type = _toType(member.type)`), dart2js
+      // failed when the underlying types had type-arguments (see
+      // dartbug.com/16925).
+      result.add(new _MirrorDeclaration(cls, member));
+    }
+
+    return result;
+  }
+}
+
+/// Implements [SymbolConverterService] using mirrors.
+class ReflectiveSymbolConverterService implements SymbolConverterService {
+  String symbolToName(Symbol symbol) => MirrorSystem.getName(symbol);
+  Symbol nameToSymbol(String name) => new Symbol(name);
+}
+
+
+// TODO(jmesserly): workaround for:
+// https://code.google.com/p/dart/issues/detail?id=10029
+Symbol _setterName(Symbol getter) =>
+    new Symbol('${MirrorSystem.getName(getter)}=');
+
+
+ClassMirror _safeSuperclass(ClassMirror type) {
+  try {
+    return type.superclass;
+  } on UnsupportedError catch (e) {
+    // Note: dart2js throws UnsupportedError when the type is not reflectable.
+    return _objectType;
+  }
+}
+
+MethodMirror _findMethod(ClassMirror type, Symbol name) {
+  do {
+    var member = type.declarations[name];
+    if (member is MethodMirror) return member;
+    type = type.superclass;
+  } while (type != null);
+}
+
+// When recursively looking for symbols up the type-hierarchy it's generally a
+// good idea to stop at Object, since we know it doesn't have what we want.
+// TODO(jmesserly): This is also a workaround for what appears to be a V8
+// bug introduced between Chrome 31 and 32. After 32
+// JsClassMirror.declarations on Object calls
+// JsClassMirror.typeVariables, which tries to get the _jsConstructor's
+// .prototype["<>"]. This ends up getting the "" property instead, maybe
+// because "<>" doesn't exist, and gets ";" which then blows up because
+// the code later on expects a List of ints.
+final _objectType = reflectClass(Object);
+
+bool _hasSetter(ClassMirror cls, MethodMirror getter) {
+  var mirror = cls.declarations[_setterName(getter.simpleName)];
+  return mirror is MethodMirror && mirror.isSetter;
+}
+
+Type _toType(TypeMirror t) {
+  // TODO(sigmund): this line can go away after dartbug.com/16962
+  if (t == _objectType) return Object;
+  if (t is ClassMirror) return t.reflectedType;
+  if (t == null || t.qualifiedName != #dynamic) {
+    _logger.warning('unknown type ($t).');
+  }
+  return dynamic;
+}
+
+class _MirrorDeclaration implements Declaration {
+  final ClassMirror _cls;
+  final _original;
+
+  _MirrorDeclaration(this._cls, DeclarationMirror this._original);
+
+  Symbol get name => _original.simpleName;
+
+  /// Whether the symbol is a property (either this or [isMethod] is true).
+  bool get isProperty => _original is VariableMirror ||
+      (_original is MethodMirror && !_original.isRegularMethod);
+
+  /// Whether the symbol is a method (either this or [isProperty] is true)
+  bool get isMethod => !isProperty;
+
+  /// If this is a property, whether it's read only (final fields or properties
+  /// with no setter).
+  bool get isFinal =>
+      (_original is VariableMirror && _original.isFinal) ||
+      (_original is MethodMirror && _original.isGetter &&
+           !_hasSetter(_cls, _original));
+
+  /// If this is a property, it's declared type (including dynamic if it's not
+  /// declared). For methods, the returned type.
+  Type get type {
+    if (_original is MethodMirror && _original.isRegularMethod) {
+      return Function;
+    }
+    var typeMirror = _original is VariableMirror ? _original.type
+        : _original.returnType;
+    return _toType(typeMirror);
+  }
+
+  /// Whether this symbol is static.
+  bool get isStatic => _original.isStatic;
+
+  /// List of annotations in this declaration.
+  List get annotations => _original.metadata.map((a) => a.reflectee).toList();
+
+  String toString() {
+    return (new StringBuffer()
+        ..write('[declaration ')
+        ..write(name)
+        ..write(isProperty ? ' (property) ' : ' (method) ')
+        ..write(isFinal ? 'final ' : '')
+        ..write(isStatic ? 'static ' : '')
+        ..write(annotations)
+        ..write(']')).toString();
+  }
+}
+
+class _MethodClosure extends Function {
+  final receiver;
+  final Symbol methodName;
+
+  _MethodClosure(this.receiver, this.methodName);
+
+  // We shouldn't need to include [call] here, but we do to work around an
+  // analyzer bug (see dartbug.com/16078). Interestingly, if [call] is invoked
+  // with the wrong number of arguments, then noSuchMethod is anyways invoked
+  // instead.
+  call() => invoke(receiver, methodName, const []);
+
+  noSuchMethod(Invocation inv) {
+    if (inv.memberName != #call) return null;
+    return invoke(receiver, methodName,
+        inv.positionalArguments, namedArgs: inv.namedArguments);
+  }
+}