A visitor that builds a map from node to "Usage".

lib/compiler/implementation/dart_backend/placeholder_collector.dart

+// Copyright (c) 2012, 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.
+
+class SendVisitor extends ResolvedVisitor {
+  final PlaceholderCollector collector;
+
+  SendVisitor(this.collector, TreeElements elements) : super(elements);
+
+  visitSuperSend(Send node) {}
+  visitOperatorSend(Send node) {}
+  visitClosureSend(Send node) {}
+  visitDynamicSend(Send node) {}
+  visitForeignSend(Send node) {}
+
+  visitGetterSend(Send node) {
+    final element = elements[node];
+    // element === null means dynamic property access.

[Anton Muhin, 2012/08/08 08:27:20]

what !isTopLevel() means?

[Roman, 2012/08/09 05:02:35]

added comment that we don't want to rename non-top-level element access.

+    if (element === null || !element.isTopLevel()) return;
+    // Unqualified <class> in static invocation, why it's not a type annotation?
+    // Another option would be to process in visitStaticSend, NB:
+    // those elements are not top-level.
+    // OR: unqualified top level.
+    collector.placeholderForElement(node.selector, element);

[Anton Muhin, 2012/08/08 08:27:20]

nit: placeholderForElement makes me think it should return something and it's
weird to see the result is discarded.

If you just want to update internal structures, maybe give it some other name:
makeElementPlaceholder/markElementPlaceholder/registerElementPlaceholder?

[Roman, 2012/08/09 05:02:35]

Done.

+    if (node.receiver !== null) {
+      // <lib prefix>.<top level>.
+      collector.placeholderForNull(node.receiver);  // Cut library prefix.
+    }
+  }
+
+  visitStaticSend(Send node) {
+    final element = elements[node];
+    if (!element.isTopLevel()) return;
+    // Another ugly case: <lib prefix>.<top level> is represented as
+    // receiver: lib prefix, selector: top level.
+    collector.placeholderForMethod(node.selector, element);
+    if (node.receiver !== null) {
+      assert(elements[node.receiver].isPrefix());
+      // Hack: putting null into map overrides receiver of original node.
+      collector.placeholderForNull(node.receiver);
+    }
+  }
+}
+
+class PlaceholderCollector extends AbstractVisitor {
+  final Compiler compiler;
+  final Map<Node, Placeholder> placeholders;
+  Element currentElement;
+  TreeElements treeElements;
+
+  PlaceholderCollector(this.compiler) :
+      placeholders = new Map<Node, Placeholder>();
+
+  void processFunction(FunctionElement element, Node node) {

[Anton Muhin, 2012/08/08 08:27:20]

nit: process (here and in the method below) is too generic, can we give it more
precise meaning?  As an idea: process -> collect (fits well
PlaceholderCollector), processFunction ->
{make,mark,registr}FunctionDeclarationPlaceholder?

[Roman, 2012/08/09 05:02:35]

Done.

+    if (element.isGenerativeConstructor() || element.isFactoryConstructor()) {
+      // Two complicated cases for class/interface renaming:
+      // 1) class which implements constructors of other interfaces, but not
+      //    implements interfaces themselves:
+      //      0.dart: class C { I(); }
+      //      1.dart and 2.dart: interface I default C { I(); }
+      //    now we have to duplicate our I() constructor in C class with
+      //    proper names.
+      // 2) (even worse for us):
+      //      0.dart: class C { C(); }
+      //      1.dart: interface C default p0.C { C(); }
+      //    the second case is just a bug now.
+      final enclosingClass = element.getEnclosingClass();
+      Node nameNode = node.name;
+      if (nameNode is Send) nameNode = nameNode.receiver;
+      // For cases like class C implements I { I(); }
+      if (nameNode.token.slowToString() == enclosingClass.name.slowToString()) {
+        placeholderForType(nameNode, enclosingClass.type);
+      }
+    } else {
+      placeholderForElement(node.name, element);
+    }
+  }
+
+  void process(Element element, TreeElements elements) {
+    if (element.isField()) {
+      // TODO(smok): In the future make sure we don't process same
+      // variable list element twice, better merge this with emitter logic.
+      element = element.variables;
+    }
+    currentElement = element;
+    treeElements = elements;
+    Node elementNode = element.parseNode(compiler);
+    if (element is FunctionElement) {
+      processFunction(element, elementNode);
+    }
+    elementNode.accept(this);
+  }
+
+  Type resolveType(TypeAnnotation typeAnnotation) {
+    if (treeElements === null) return null;
+    var result = treeElements.getType(typeAnnotation);
+    // TODO: Have better type resolution.
+    if (result === null) {
+      result = compiler.resolveTypeAnnotation(currentElement, typeAnnotation);
+    }
+    return result;
+  }
+
+  void placeholderForType(Node node, Type type) {
+    assert(type !== null);
+    placeholders[node] = new TypePlaceholder(type);
+  }

[Anton Muhin, 2012/08/08 08:27:20]

nit: blank lines between methods, please

[Roman, 2012/08/09 05:02:35]

Done.

+  void placeholderForMethod(Node node, Element method) {
+    assert(method !== null);
+    assert(method is FunctionElement || method is VariableElement);
+    placeholders[node] = new MethodPlaceholder(method);
+  }
+  void placeholderForNull(Node node) {
+    placeholders[node] = new NullPlaceholder();
+  }
+  void placeholderForElement(Node node, Element element) {
+    assert(element !== null);
+    placeholders[node] = new ElementPlaceholder(element);
+  }
+
+  void internalError(String reason, [Node node]) {
+    compiler.cancel(reason: reason, node: node);
+  }
+
+  visit(Node node) => (node === null) ? null : node.accept(this);
+  visitNode(Node node) { node.visitChildren(this); }  // We must go deeper.

[Anton Muhin, 2012/08/08 08:27:20]

memegen link? :)

+
+  visitClassNode(ClassNode node) {
+    internalError('Should never meet ClassNode', node);
+  }
+
+  visitSend(Send send) {
+    new SendVisitor(this, treeElements).visitSend(send);
+    send.visitChildren(this);

[Anton Muhin, 2012/08/08 08:27:20]

super.visitSend(send)?

[Roman, 2012/08/09 05:02:35]

Done.

+  }
+
+  visitTypeAnnotation(TypeAnnotation node) {
+    final type = compiler.resolveTypeAnnotation(currentElement, node);
+    if (type is !InterfaceType) return null;
+    var target = node.typeName;
+    if (node.typeName is Send) {
+      final element = treeElements[node];
+      if (element !== null) {
+        final send = node.typeName.asSend();
+        final isPrefixed = element.lookupConstructor(

[Anton Muhin, 2012/08/08 08:27:20]

nit: please, rename isPrefixed -> hasPrefix

[Roman, 2012/08/09 05:02:35]

Done.

+          send.receiver.source, send.selector.source) === null;
+        if (!isPrefixed) target = send.receiver;
+      }
+    }
+    placeholderForType(target, type);
+    visit(node.typeArguments);

[Anton Muhin, 2012/08/08 08:27:20]

super.visitTypeAnnotation(node)?

[Roman, 2012/08/09 05:02:35]

Done.

+  }
+}