sdk/pkg/kernel/lib/binary/limited_ast_to_binary.dart

// Copyright (c) 2017, 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.

import 'package:kernel/ast.dart';
import 'package:kernel/binary/ast_to_binary.dart';

/// Writes libraries that satisfy the [predicate].
///
/// Only the referenced subset of canonical names is indexed and written,
/// so we don't waste time indexing all libraries of a program, when only
/// a tiny subset is used.
class LimitedBinaryPrinter extends BinaryPrinter {
  final LibraryFilter predicate;

  LimitedBinaryPrinter(Sink<List<int>> sink, this.predicate)
      : super(sink, stringIndexer: new ReferencesStringIndexer());

  @override
  void addCanonicalNamesForLinkTable(List<CanonicalName> list) {
    ReferencesStringIndexer stringIndexer = this.stringIndexer;
    stringIndexer.referencedNames.forEach((name) {
      if (name.index != -1) return;
      name.index = list.length;
      list.add(name);
    });
  }

  @override
  void buildStringIndex(Program program) {
    program.libraries.where(predicate).forEach((library) {
      stringIndexer.scanLibrary(library);
    });
    stringIndexer.finish();
  }

  @override
  bool shouldWriteLibraryCanonicalNames(Library library) {
    return predicate(library);
  }

  @override
  void writeLibraries(Program program) {
    var librariesToWrite = program.libraries.where(predicate).toList();
    writeList(librariesToWrite, writeNode);
  }

  @override
  void writeNode(Node node) {
    if (node is Library && !predicate(node)) return;
    node.accept(this);
  }
}

/// Extension of [StringIndexer] that also indexes canonical names of
/// referenced classes and members.
class ReferencesStringIndexer extends StringIndexer {
  final List<CanonicalName> referencedNames = <CanonicalName>[];

  defaultMemberReference(Member node) {
    _handleReferencedName(node.canonicalName);
  }

  visitClassReference(Class node) {
    _handleReferencedName(node.canonicalName);
  }

  void _handleReferencedName(CanonicalName name) {
    if (name == null || name.parent == null) return;
    _handleReferencedName(name.parent);
    referencedNames.add(name);
    name.index = -1;
    put(name.name);
  }
}