pkg/front_end/lib/src/fasta/builder/prefix_builder.dart

// Copyright (c) 2016, 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 fasta.prefix_builder;

import 'builder.dart' show Builder, LibraryBuilder, MemberBuilder;

import '../messages.dart' show warning;

import 'package:kernel/ast.dart' show Member;

import '../dill/dill_member_builder.dart' show DillMemberBuilder;

import '../errors.dart' show internalError;

class PrefixBuilder extends Builder {
  final String name;

  final Map<String, Builder> exports;

  final LibraryBuilder parent;

  PrefixBuilder(this.name, this.exports, LibraryBuilder parent, int charOffset)
      : parent = parent,
        super(parent, charOffset, parent.fileUri);

  Member findTopLevelMember(String name) {
    // TODO(ahe): Move this to KernelPrefixBuilder.
    Builder builder = exports[name];
    if (builder == null) {
      warning(
          parent.fileUri, -1, "'${this.name}' has no member named '$name'.");
    }
    if (builder is DillMemberBuilder) {
      return builder.member.isInstanceMember
          ? internalError("Unexpected instance member in export scope")
          : builder.member;
    } else if (builder is MemberBuilder) {
      return builder.target;
    } else {
      return null;
    }
  }

  Builder combineAmbiguousImport(
      String name, Builder other, LibraryBuilder library) {
    if (other is PrefixBuilder) {
      /// Handles the case where the same prefix is used for different imports.
      other.exports.forEach((String name, Builder member) {
        Builder existing = exports[name];
        if (existing != null) {
          member = existing.combineAmbiguousImport(name, member, library);
        }
        exports[name] = member;
      });
      return this;
    }
    return super.combineAmbiguousImport(name, other, library);
  }
}