dart2js: Rename metadata_emitter.dart to metadata_collector.dart.

pkg/compiler/lib/src/js_emitter/metadata_emitter.dart

-// Copyright (c) 2013, 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.
-
-part of dart2js.js_emitter;
-
-class MetadataCollector {
-  final Compiler _compiler;
-  final Emitter _emitter;
-
-  /// A list of JS expressions that represent metadata, parameter names and
-  /// type, and return types.
-  final List<String> globalMetadata = [];
-
-  /// A map used to canonicalize the entries of globalMetadata.
-  final Map<String, int> _globalMetadataMap = <String, int>{};
-
-  MetadataCollector(this._compiler, this._emitter);
-
-  JavaScriptBackend get _backend => _compiler.backend;
-  TypeVariableHandler get _typeVariableHandler => _backend.typeVariableHandler;
-
-  bool _mustEmitMetadataFor(Element element) {
-    return _backend.mustRetainMetadata &&
-        _backend.referencedFromMirrorSystem(element);
-  }
-
-  /// The metadata function returns the metadata associated with
-  /// [element] in generated code.  The metadata needs to be wrapped
-  /// in a function as it refers to constants that may not have been
-  /// constructed yet.  For example, a class is allowed to be
-  /// annotated with itself.  The metadata function is used by
-  /// mirrors_patch to implement DeclarationMirror.metadata.
-  jsAst.Fun buildMetadataFunction(Element element) {
-    if (!_mustEmitMetadataFor(element)) return null;
-    return _compiler.withCurrentElement(element, () {
-      List<jsAst.Expression> metadata = <jsAst.Expression>[];
-      Link link = element.metadata;
-      // TODO(ahe): Why is metadata sometimes null?
-      if (link != null) {
-        for (; !link.isEmpty; link = link.tail) {
-          MetadataAnnotation annotation = link.head;
-          ConstantExpression constant =
-              _backend.constants.getConstantForMetadata(annotation);
-          if (constant == null) {
-            _compiler.internalError(annotation, 'Annotation value is null.');
-          } else {
-            metadata.add(_emitter.constantReference(constant.value));
-          }
-        }
-      }
-      if (metadata.isEmpty) return null;
-      return js('function() { return # }',
-          new jsAst.ArrayInitializer(metadata));
-    });
-  }
-
-  List<int> reifyDefaultArguments(FunctionElement function) {
-    FunctionSignature signature = function.functionSignature;
-    if (signature.optionalParameterCount == 0) return const [];
-    List<int> defaultValues = <int>[];
-    for (ParameterElement element in signature.optionalParameters) {
-      ConstantExpression constant =
-          _backend.constants.getConstantForVariable(element);
-      String stringRepresentation = (constant == null)
-          ? "null"
-          : jsAst.prettyPrint(
-              _emitter.constantReference(constant.value), _compiler).getText();
-      defaultValues.add(addGlobalMetadata(stringRepresentation));
-    }
-    return defaultValues;
-  }
-
-  int reifyMetadata(MetadataAnnotation annotation) {
-    ConstantExpression constant =
-        _backend.constants.getConstantForMetadata(annotation);
-    if (constant == null) {
-      _compiler.internalError(annotation, 'Annotation value is null.');
-      return -1;
-    }
-    return addGlobalMetadata(
-        jsAst.prettyPrint(
-            _emitter.constantReference(constant.value), _compiler).getText());
-  }
-
-  int reifyType(DartType type) {
-    jsAst.Expression representation =
-        _backend.rti.getTypeRepresentation(
-            type,
-            (variable) {
-              return js.number(
-                  _typeVariableHandler.reifyTypeVariable(
-                      variable.element));
-            },
-            (TypedefType typedef) {
-              return _backend.isAccessibleByReflection(typedef.element);
-            });
-
-    return addGlobalMetadata(
-        jsAst.prettyPrint(representation, _compiler).getText());
-  }
-
-  int reifyName(String name) {
-    return addGlobalMetadata('"$name"');
-  }
-
-  int addGlobalMetadata(String string) {
-    return _globalMetadataMap.putIfAbsent(string, () {
-      globalMetadata.add(string);
-      return globalMetadata.length - 1;
-    });
-  }
-
-  List<int> computeMetadata(FunctionElement element) {
-    return _compiler.withCurrentElement(element, () {
-      if (!_mustEmitMetadataFor(element)) return const <int>[];
-      List<int> metadata = <int>[];
-      Link link = element.metadata;
-      // TODO(ahe): Why is metadata sometimes null?
-      if (link != null) {
-        for (; !link.isEmpty; link = link.tail) {
-          metadata.add(reifyMetadata(link.head));
-        }
-      }
-      return metadata;
-    });
-  }
-}