pkg/front_end/lib/src/base/name_space.dart

// Copyright (c) 2024, 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 '../builder/builder.dart';
import '../builder/library_builder.dart';
import 'lookup_result.dart';
import 'scope.dart';
import 'uris.dart';

abstract class NameSpace {
  /// Returns the [LookupResult] for the [Builder]s of the given [name] in the
  /// name space.
  LookupResult? lookup(String name);
}

abstract class MutableNameSpace implements NameSpace {
  void addLocalMember(String name, NamedBuilder member, {required bool setter});
}

abstract class ComputedNameSpace implements NameSpace {
  /// Returns a filtered iterator of members and setters mapped in this name
  /// space.
  ///
  /// Only members of type [T] are included. Duplicates are not included.
  Iterator<T> filteredIterator<T extends NamedBuilder>();
}

abstract class ComputedMutableNameSpace
    implements MutableNameSpace, ComputedNameSpace {
  factory() = ComputedMutableNameSpaceImpl._;

  void replaceLocalMember(
    String name,
    NamedBuilder member, {
    required bool setter,
  });
}

abstract class DeclarationNameSpace({
  required final Map<String, MemberLookupResult> _content,
  required final Map<String, MemberLookupResult> _constructors,
}) implements NameSpace {
  @override
  MemberLookupResult? lookup(String name) => _content[name];

  MemberLookupResult? lookupConstructor(String name) => _constructors[name];
}

base class ComputedMutableNameSpaceImpl implements ComputedMutableNameSpace {
  Map<String, LookupResult>? _content;

  new _();

  @override
  void addLocalMember(
    String name,
    NamedBuilder member, {
    required bool setter,
  }) {
    Map<String, LookupResult> content = _content ??= {};
    LookupResult? existing = content[name];
    if (existing != null) {
      if (setter) {
        assert(
          existing.setable == null ||
              // Coverage-ignore(suite): Not run.
              existing.setable == member,
          "Trying to map setable $member to $name "
          "replacing the existing value ${existing.setable}",
        );
        if (existing.getable != null) {
          content[name] = new GetableSetableResult(existing.getable!, member);
          return;
        }
      } else {
        assert(
          existing.getable == null || existing.getable == member,
          "Trying to map getable $member to $name "
          "replacing the existing value ${existing.getable}",
        );
        if (existing.setable != null) {
          content[name] = new GetableSetableResult(member, existing.setable!);
          return;
        }
      }
    }
    if (member is LookupResult) {
      content[name] = member as LookupResult;
    } else {
      content[name] = setter
          ?
            // Coverage-ignore(suite): Not run.
            new SetableResult(member)
          : new GetableResult(member);
    }
  }

  @override
  void replaceLocalMember(
    String name,
    NamedBuilder member, {
    required bool setter,
  }) {
    Map<String, LookupResult> content = _content!;
    LookupResult? existing = content[name];
    assert(existing != null, "No existing result for $name.");
    if (existing != null) {
      if (setter) {
        assert(
          existing.setable != null,
          "Trying to map setable $member to $name "
          "replacing the existing value ${existing.setable}",
        );
        if (existing.getable != null) {
          content[name] = new GetableSetableResult(existing.getable!, member);
          return;
        }
      } else {
        assert(
          existing.getable != null,
          "Trying to map setable $member to $name "
          "replacing the existing value ${existing.getable}",
        );
        if (existing.setable != null) {
          content[name] = new GetableSetableResult(member, existing.setable!);
          return;
        }
      }
    }
    if (member is LookupResult) {
      content[name] = member as LookupResult;
    } else {
      // Coverage-ignore-block(suite): Not run.
      content[name] = setter
          ? new SetableResult(member)
          : new GetableResult(member);
    }
  }

  @override
  Iterator<T> filteredIterator<T extends NamedBuilder>() {
    return new FilteredIterator<T>(
      new LookupResultIterator(_content?.values.iterator),
      includeDuplicates: false,
    );
  }

  @override
  LookupResult? lookup(String name) => _content?[name];
}

final class LibraryNameSpace({
  required final Map<String, LookupResult> _content,
}) implements NameSpace {
  void addLocalMember(String name, LookupResult member) {
    assert(
      !_content.containsKey(name),
      "Unexpected replacement of ${_content[name]} by $member.",
    );
    _content[name] = member;
  }

  @override
  LookupResult? lookup(String name) => _content[name];
}

// Coverage-ignore(suite): Not run.
/// Returns a string with an error message if [sourceNameSpace] and
/// [dillNameSpace] are not equivalent.
///
/// This should be used for assertions only.
String? areNameSpacesEquivalent({
  required Uri importUri,
  required NameSpace sourceNameSpace,
  required NameSpace dillNameSpace,
}) {
  sourceNameSpace as ComputedMutableNameSpaceImpl;
  dillNameSpace as ComputedMutableNameSpaceImpl;

  bool isEquivalent = true;
  StringBuffer sb = new StringBuffer();
  sb.writeln('Mismatch on ${importUri}:');

  Map<String, LookupResult>? sourceContent = sourceNameSpace._content;
  Map<String, LookupResult>? dillContent = dillNameSpace._content;

  if (sourceContent != null) {
    for (MapEntry<String, LookupResult> sourceEntry in sourceContent.entries) {
      LookupResult sourceResult = sourceEntry.value;
      LookupResult? dillResult = dillContent?[sourceEntry.key];
      if (sourceResult.getable != null) {
        if (dillResult?.getable == null) {
          if ((sourceEntry.key == 'dynamic' || sourceEntry.key == 'Never') &&
              importUri == dartCore) {
            // The source library builder for dart:core has synthetically
            // injected builders for `dynamic` and `Never` which do not have
            // corresponding classes in the AST.
          } else {
            sb.writeln(
              'No dill getable for ${sourceEntry.key}: ${sourceResult}',
            );
            isEquivalent = false;
          }
        }
      }
      if (sourceResult.setable != null) {
        if (dillResult?.setable == null) {
          sb.writeln('No dill setable for ${sourceEntry.key}: ${sourceResult}');
          isEquivalent = false;
        }
      }
    }
  }
  if (dillContent != null) {
    for (MapEntry<String, LookupResult> dillEntry in dillContent.entries) {
      LookupResult dillResult = dillEntry.value;
      LookupResult? sourceResult = sourceContent?[dillEntry.key];
      if (dillResult.getable != null) {
        if (sourceResult?.getable != null) {
          sb.writeln('No source getable for ${dillEntry.key}=: ${dillResult}');
          isEquivalent = false;
        }
      }
      if (dillResult.setable != null) {
        if (sourceResult?.setable != null) {
          sb.writeln('No source setable for ${dillEntry.key}=: ${dillResult}');
          isEquivalent = false;
        }
      }
    }
  }

  if (isEquivalent) {
    return null;
  }
  return sb.toString();
}

final class SourceDeclarationNameSpace({
  required super.content,
  required super.constructors,
}) extends DeclarationNameSpace {
  void addConstructor(String name, MemberLookupResult constructor) {
    assert(
      !_constructors.containsKey(name),
      "Unexpected existing constructor ${_constructors[name]}, "
      "trying to add ${constructor}.",
    );
    _constructors[name] = constructor;
  }

  void addLocalMember(String name, MemberLookupResult member) {
    assert(
      !_content.containsKey(name),
      "Unexpected replacement of ${_content[name]} by $member.",
    );
    _content[name] = member;
  }
}

final class DillDeclarationNameSpace({
  required super.content,
  required super.constructors,
}) extends DeclarationNameSpace;

final class DillExportNameSpace extends ComputedMutableNameSpaceImpl {
  new() : super._();

  /// Patch up the scope, using the two replacement maps to replace builders in
  /// scope. The replacement maps from old LibraryBuilder to map, mapping
  /// from name to new (replacement) builder.
  void patchUpScope(Map<LibraryBuilder, NameSpace> replacementNameSpaceMap) {
    // In the following we refer to non-setters as 'getters' for brevity.
    //
    // We have to replace all getters and setters in [_locals] and [_setters]
    // with the corresponding getters and setters in [replacementMap]
    // and [replacementMapSetters].
    //
    // Since field builders can be replaced by getter and setter builders and
    // vice versa when going from source to dill builder and back, we might not
    // have a 1-to-1 relationship between the existing and replacing builders.
    //
    // For this reason we start by collecting the names of all getters/setters
    // that need (some) replacement. Afterwards we go through these names
    // handling both getters and setters at the same time.

    Set<String> replacedNames = {};
    _content?.forEach((String name, LookupResult result) {
      if (replacementNameSpaceMap.containsKey(result.getable?.parent)) {
        replacedNames.add(name);
      }
      if (replacementNameSpaceMap.containsKey(result.setable?.parent)) {
        replacedNames.add(name);
      }
    });
    if (replacedNames.isNotEmpty) {
      for (String name in replacedNames) {
        // We start be collecting the relation between an existing getter/setter
        // and the getter/setter that will replace it. This information is used
        // below to handle all the different cases that can occur.
        LookupResult existingResult = _content![name]!;
        NamedBuilder? existingGetter = existingResult.getable;
        NamedBuilder? existingSetter = existingResult.setable;
        LookupResult? replacementResult;
        if (existingGetter != null && existingSetter != null) {
          if (existingGetter == existingSetter) {
            replacementResult = replacementNameSpaceMap[existingGetter.parent]!
                .lookup(name);
          } else {
            NamedBuilder? replacementGetter =
                replacementNameSpaceMap[existingGetter.parent]
                    ?.lookup(name)
                    ?.getable;
            NamedBuilder? replacementSetter =
                replacementNameSpaceMap[existingSetter.parent]
                    ?.lookup(name)
                    ?.setable;
            replacementResult = LookupResult.createResult(
              replacementGetter ?? existingGetter,
              replacementSetter ?? existingSetter,
            );
          }
        } else if (existingGetter != null) {
          replacementResult = LookupResult.createResult(
            replacementNameSpaceMap[existingGetter.parent]
                ?.lookup(name)
                ?.getable,
            null,
          );
        } else if (existingSetter != null) {
          replacementResult = LookupResult.createResult(
            null,
            replacementNameSpaceMap[existingSetter.parent]
                ?.lookup(name)
                ?.setable,
          );
        }
        if (replacementResult != null) {
          (_content ??= // Coverage-ignore(suite): Not run.
                  {})[name] =
              replacementResult;
        } else {
          // Coverage-ignore-block(suite): Not run.
          _content?.remove(name);
        }
      }
    }
  }
}