Merge pull request #581 from kevmoo/polymer

lib/src/observable_transform.dart

Index: lib/src/observable_transform.dart
diff --git a/lib/src/observable_transform.dart b/lib/src/observable_transform.dart
deleted file mode 100644
index 88b1cad3a5fb4339337c4e6a2816dc1be8923358..0000000000000000000000000000000000000000
--- a/lib/src/observable_transform.dart
+++ /dev/null
@@ -1,325 +0,0 @@
-// 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.
-
-/**
- * Code transform for @observable. The core transformation is relatively
- * straightforward, and essentially like an editor refactoring. You can find the
- * core implementation in [transformClass], which is ultimately called by
- * [transformObservables], the entry point to this library.
- */
-library observable_transform;
-
-import 'package:analyzer_experimental/src/generated/ast.dart';
-import 'package:analyzer_experimental/src/generated/error.dart';
-import 'package:analyzer_experimental/src/generated/scanner.dart';
-import 'package:source_maps/span.dart' show SourceFile;
-import 'dart_parser.dart';
-import 'messages.dart';
-import 'refactor.dart';
-
-/**
- * Transform types in Dart [userCode] marked with `@observable` by hooking all
- * field setters, and notifying the observation system of the change. If the
- * code was changed this returns true, otherwise returns false. Modified code
- * can be found in [userCode.code].
- *
- * Note: there is no special checking for transitive immutability. It is up to
- * the rest of the observation system to handle check for this condition and
- * handle it appropriately. We do not want to violate reference equality of
- * any fields that are set into the object.
- */
-TextEditTransaction transformObservables(DartCodeInfo userCode,
-    Messages messages) {
-
-  if (userCode == null || userCode.compilationUnit == null) return null;
-  var transaction = new TextEditTransaction(userCode.code, userCode.sourceFile);
-  transformCompilationUnit(userCode, transaction, messages);
-  return transaction;
-}
-
-void transformCompilationUnit(DartCodeInfo userCode, TextEditTransaction code,
-    Messages messages) {
-
-  var unit = userCode.compilationUnit;
-  for (var directive in unit.directives) {
-    if (directive is LibraryDirective && hasObservable(directive)) {
-      messages.warning('@observable on a library no longer has any effect. '
-          'It should be placed on individual fields.',
-          _getSpan(userCode.sourceFile, directive));
-      break;
-    }
-  }
-
-  for (var declaration in unit.declarations) {
-    if (declaration is ClassDeclaration) {
-      transformClass(declaration, code, userCode.sourceFile, messages);
-    } else if (declaration is TopLevelVariableDeclaration) {
-      if (hasObservable(declaration)) {
-        messages.warning('Top-level fields can no longer be observable. '
-            'Observable fields should be put in an observable objects.',
-            _getSpan(userCode.sourceFile, declaration));
-      }
-    }
-  }
-}
-
-_getSpan(SourceFile file, ASTNode node) => file.span(node.offset, node.end);
-
-/** True if the node has the `@observable` annotation. */
-bool hasObservable(AnnotatedNode node) => hasAnnotation(node, 'observable');
-
-bool hasAnnotation(AnnotatedNode node, String name) {
-  // TODO(jmesserly): this isn't correct if the annotation has been imported
-  // with a prefix, or cases like that. We should technically be resolving, but
-  // that is expensive.
-  return node.metadata.any((m) => m.name.name == name &&
-      m.constructorName == null && m.arguments == null);
-}
-
-void transformClass(ClassDeclaration cls, TextEditTransaction code,
-    SourceFile file, Messages messages) {
-
-  if (hasObservable(cls)) {
-    messages.warning('@observable on a class no longer has any effect. '
-        'It should be placed on individual fields.',
-        _getSpan(file, cls));
-  }
-
-  // We'd like to track whether observable was declared explicitly, otherwise
-  // report a warning later below. Because we don't have type analysis (only
-  // syntactic understanding of the code), we only report warnings that are
-  // known to be true.
-  var declaresObservable = false;
-  if (cls.extendsClause != null) {
-    var id = _getSimpleIdentifier(cls.extendsClause.superclass.name);
-    if (id.name == 'ObservableBase') {
-      code.edit(id.offset, id.end, 'ChangeNotifierBase');
-      declaresObservable = true;
-    } else if (id.name == 'ChangeNotifierBase') {
-      declaresObservable = true;
-    } else if (id.name != 'PolymerElement' && id.name != 'CustomElement'
-        && id.name != 'Object') {
-      // TODO(sigmund): this is conservative, consider using type-resolution to
-      // improve this check.
-      declaresObservable = true;
-    }
-  }
-
-  if (cls.withClause != null) {
-    for (var type in cls.withClause.mixinTypes) {
-      var id = _getSimpleIdentifier(type.name);
-      if (id.name == 'ObservableMixin') {
-        code.edit(id.offset, id.end, 'ChangeNotifierMixin');
-        declaresObservable = true;
-        break;
-      } else if (id.name == 'ChangeNotifierMixin') {
-        declaresObservable = true;
-        break;
-      } else {
-        // TODO(sigmund): this is conservative, consider using type-resolution
-        // to improve this check.
-        declaresObservable = true;
-      }
-    }
-  }
-
-  if (!declaresObservable && cls.implementsClause != null) {
-    // TODO(sigmund): consider adding type-resolution to give a more precise
-    // answer.
-    declaresObservable = true;
-  }
-
-  // Track fields that were transformed.
-  var instanceFields = new Set<String>();
-  var getters = new List<String>();
-  var setters = new List<String>();
-
-  for (var member in cls.members) {
-    if (member is FieldDeclaration) {
-      bool isStatic = hasKeyword(member.keyword, Keyword.STATIC);
-      if (isStatic) {
-        if (hasObservable(member)){
-          messages.warning('Static fields can no longer be observable. '
-              'Observable fields should be put in an observable objects.',
-              _getSpan(file, member));
-        }
-        continue;
-      }
-      if (hasObservable(member)) {
-        if (!declaresObservable) {
-          messages.warning('Observable fields should be put in an observable'
-              ' objects. Please declare that this class extends from '
-              'ObservableBase, includes ObservableMixin, or implements '
-              'Observable.',
-              _getSpan(file, member));
-
-        }
-        transformFields(member.fields, code, member.offset, member.end);
-
-        var names = member.fields.variables.map((v) => v.name.name);
-
-        getters.addAll(names);
-        if (!_isReadOnly(member.fields)) {
-          setters.addAll(names);
-          instanceFields.addAll(names);
-        }
-      }
-    }
-    // TODO(jmesserly): this is a temporary workaround until we can remove
-    // getValueWorkaround and setValueWorkaround.
-    if (member is MethodDeclaration) {
-      if (hasKeyword(member.propertyKeyword, Keyword.GET)) {
-        getters.add(member.name.name);
-      } else if (hasKeyword(member.propertyKeyword, Keyword.SET)) {
-        setters.add(member.name.name);
-      }
-    }
-  }
-
-  // If nothing was @observable, bail.
-  if (instanceFields.length == 0) return;
-
-  if (getters.length > 0 || setters.length > 0) {
-    mirrorWorkaround(cls, code, getters, setters);
-  }
-
-  // Fix initializers, because they aren't allowed to call the setter.
-  for (var member in cls.members) {
-    if (member is ConstructorDeclaration) {
-      fixConstructor(member, code, instanceFields);
-    }
-  }
-}
-
-SimpleIdentifier _getSimpleIdentifier(Identifier id) =>
-    id is PrefixedIdentifier ? id.identifier : id;
-
-
-/**
- * Generates `getValueWorkaround` and `setValueWorkaround`. These will go away
- * shortly once dart2js supports mirrors. For the moment they provide something
- * that the binding system can use.
- */
-void mirrorWorkaround(ClassDeclaration cls, TextEditTransaction code,
-    List<String> getters, List<String> setters) {
-
-  var sb = new StringBuffer('\ngetValueWorkaround(key) {\n');
-  for (var name in getters) {
-    if (name.startsWith('_')) continue;
-    sb.write("  if (key == const Symbol('$name')) return this.$name;\n");
-  }
-  sb.write('  return null;\n}\n');
-  sb.write('\nsetValueWorkaround(key, value) {\n');
-  for (var name in setters) {
-    if (name.startsWith('_')) continue;
-    sb.write("  if (key == const Symbol('$name')) "
-        "{ this.$name = value; return; }\n");
-  }
-  sb.write('}\n');
-
-  int pos = cls.rightBracket.offset;
-  var indent = guessIndent(code.original, pos);
-
-  code.edit(pos, pos, sb.toString().replaceAll('\n', '\n$indent  '));
-}
-
-bool hasKeyword(Token token, Keyword keyword) =>
-    token is KeywordToken && (token as KeywordToken).keyword == keyword;
-
-String getOriginalCode(TextEditTransaction code, ASTNode node) =>
-    code.original.substring(node.offset, node.end);
-
-void fixConstructor(ConstructorDeclaration ctor, TextEditTransaction code,
-    Set<String> changedFields) {
-
-  // Fix normal initializers
-  for (var initializer in ctor.initializers) {
-    if (initializer is ConstructorFieldInitializer) {
-      var field = initializer.fieldName;
-      if (changedFields.contains(field.name)) {
-        code.edit(field.offset, field.end, '__\$${field.name}');
-      }
-    }
-  }
-
-  // Fix "this." initializer in parameter list. These are tricky:
-  // we need to preserve the name and add an initializer.
-  // Preserving the name is important for named args, and for dartdoc.
-  // BEFORE: Foo(this.bar, this.baz) { ... }
-  // AFTER:  Foo(bar, baz) : __$bar = bar, __$baz = baz { ... }
-
-  var thisInit = [];
-  for (var param in ctor.parameters.parameters) {
-    if (param is DefaultFormalParameter) {
-      param = param.parameter;
-    }
-    if (param is FieldFormalParameter) {
-      var name = param.identifier.name;
-      if (changedFields.contains(name)) {
-        thisInit.add(name);
-        // Remove "this." but keep everything else.
-        code.edit(param.thisToken.offset, param.period.end, '');
-      }
-    }
-  }
-
-  if (thisInit.length == 0) return;
-
-  // TODO(jmesserly): smarter formatting with indent, etc.
-  var inserted = thisInit.map((i) => '__\$$i = $i').join(', ');
-
-  int offset;
-  if (ctor.separator != null) {
-    offset = ctor.separator.end;
-    inserted = ' $inserted,';
-  } else {
-    offset = ctor.parameters.end;
-    inserted = ' : $inserted';
-  }
-
-  code.edit(offset, offset, inserted);
-}
-
-bool _isReadOnly(VariableDeclarationList fields) {
-  return hasKeyword(fields.keyword, Keyword.CONST) ||
-      hasKeyword(fields.keyword, Keyword.FINAL);
-}
-
-void transformFields(VariableDeclarationList fields, TextEditTransaction code,
-    int begin, int end) {
-
-  if (_isReadOnly(fields)) return;
-
-  var indent = guessIndent(code.original, begin);
-  var replace = new StringBuffer();
-
-  // Unfortunately "var" doesn't work in all positions where type annotations
-  // are allowed, such as "var get name". So we use "dynamic" instead.
-  var type = 'dynamic';
-  if (fields.type != null) {
-    type = getOriginalCode(code, fields.type);
-  }
-
-  for (var field in fields.variables) {
-    var initializer = '';
-    if (field.initializer != null) {
-      initializer = ' = ${getOriginalCode(code, field.initializer)}';
-    }
-
-    var name = field.name.name;
-
-    // TODO(jmesserly): should we generate this one one line, so source maps
-    // don't break?
-    if (replace.length > 0) replace.write('\n\n$indent');
-    replace.write('''
-$type __\$$name$initializer;
-$type get $name => __\$$name;
-set $name($type value) {
-  __\$$name = notifyPropertyChange(const Symbol('$name'), __\$$name, value);
-}
-'''.replaceAll('\n', '\n$indent'));
-  }
-
-  code.edit(begin, end, '$replace');
-}