pkg/compiler/lib/src/kernel/deferred_load.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.

library kernel.deferred_load_data;

import 'package:kernel/ast.dart' as ir;

import '../compiler.dart' show Compiler;
import '../constants/values.dart' show ConstantValue;
import '../deferred_load.dart';
import '../elements/entities.dart';
import 'element_map.dart';

class KernelDeferredLoadTask extends DeferredLoadTask {
  KernelToElementMapForImpact _elementMap;

  KernelDeferredLoadTask(Compiler compiler, this._elementMap) : super(compiler);

  @override
  Iterable<ImportEntity> importsTo(Entity element, LibraryEntity library) {
    if (element is! MemberEntity) return const <ImportEntity>[];
    List<ImportEntity> imports = [];
    ir.Library source = _elementMap.getLibraryNode(library);
    ir.Member member = _elementMap.getMemberDefinition(element).node;
    for (ir.LibraryDependency dependency in source.dependencies) {
      if (dependency.isExport) continue;
      if (!_isVisible(dependency.combinators, member.name.name)) continue;
      if (member.enclosingLibrary == dependency.targetLibrary ||
          dependency.targetLibrary.additionalExports
              .any((ir.Reference ref) => ref.node == member)) {
        imports.add(_elementMap.getImport(dependency));
      }
    }
    return imports;
  }

  @override
  void checkForDeferredErrorCases(LibraryEntity library) {
    // Nothing to do. The FE checks for error cases upfront.
  }

  @override
  void collectConstantsInBody(
      covariant MemberEntity element, Set<ConstantValue> constants) {
    // TODO(redemption): write visitor to extract constants.
  }

  /// Adds extra dependencies coming from mirror usage.
  @override
  void addDeferredMirrorElements(WorkQueue queue) {
    throw new UnsupportedError(
        "KernelDeferredLoadTask.addDeferredMirrorElements");
  }

  /// Add extra dependencies coming from mirror usage in [root] marking it with
  /// [newSet].
  @override
  void addMirrorElementsForLibrary(
      WorkQueue queue, LibraryEntity root, ImportSet newSet) {
    throw new UnsupportedError(
        "KernelDeferredLoadTask.addMirrorElementsForLibrary");
  }
}

/// Returns whether [name] would be visible according to the given list of
/// show/hide [combinators].
bool _isVisible(List<ir.Combinator> combinators, String name) {
  for (var c in combinators) {
    if (c.isShow && !c.names.contains(name)) return false;
    if (c.isHide && c.names.contains(name)) return false;
  }
  return true;
}