Elements. Make PrefixFragmentImpl.name2 nullable.

Change-Id: Ifddd477184333e62622615c44da58e51b94f0b92
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/390809
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/lib/dart/element/element2.dart

@@ -917,7 +917,7 @@ abstract class FragmentName {
   String get name;
 
   /// The offset of the end of the name.
-  int? get nameEnd;
+  int get nameEnd;
 
   /// The offset of the name in the file.
   int get nameOffset;

pkg/analyzer/lib/src/dart/analysis/driver.dart

@@ -96,7 +96,7 @@ import 'package:meta/meta.dart';
 // TODO(scheglov): Clean up the list of implicitly analyzed files.
 class AnalysisDriver {
   /// The version of data format, should be incremented on every format change.
-  static const int DATA_VERSION = 400;
+  static const int DATA_VERSION = 401;
 
   /// The number of exception contexts allowed to write. Once this field is
   /// zero, we stop writing any new exception contexts in this process.

pkg/analyzer/lib/src/dart/analysis/file_state.dart

@@ -1219,11 +1219,19 @@ class FileState {
     UnlinkedLibraryImportPrefix? unlinkedPrefix;
     var prefix = node.prefix;
     if (prefix != null) {
+      UnlinkedLibraryImportPrefixName? name;
+      if (!prefix.isSynthetic) {
+        name = UnlinkedLibraryImportPrefixName(
+          name: prefix.name,
+          nameOffset: prefix.offset,
+        );
+      }
+
       unlinkedPrefix = UnlinkedLibraryImportPrefix(
         deferredOffset: node.deferredKeyword?.offset,
         asOffset: node.asKeyword!.offset,
-        name: prefix.name,
         nameOffset: prefix.offset,
+        name: name,
       );
     }
 

pkg/analyzer/lib/src/dart/analysis/unlinked_data.dart

@@ -260,28 +260,54 @@ class UnlinkedLibraryImportDirective extends UnlinkedNamespaceDirective {
 class UnlinkedLibraryImportPrefix {
   final int? deferredOffset;
   final int asOffset;
-  final String name;
   final int nameOffset;
+  final UnlinkedLibraryImportPrefixName? name;
 
   UnlinkedLibraryImportPrefix({
     required this.deferredOffset,
     required this.asOffset,
-    required this.name,
     required this.nameOffset,
+    required this.name,
   });
 
   factory UnlinkedLibraryImportPrefix.read(SummaryDataReader reader) {
     return UnlinkedLibraryImportPrefix(
       deferredOffset: reader.readOptionalUInt30(),
       asOffset: reader.readUInt30(),
-      name: reader.readStringUtf8(),
       nameOffset: reader.readUInt30(),
+      name: reader.readOptionalObject((reader) {
+        return UnlinkedLibraryImportPrefixName.read(reader);
+      }),
     );
   }
 
   void write(BufferedSink sink) {
     sink.writeOptionalUInt30(deferredOffset);
     sink.writeUInt30(asOffset);
+    sink.writeUInt30(nameOffset);
+    sink.writeOptionalObject(name, (name) {
+      name.write(sink);
+    });
+  }
+}
+
+class UnlinkedLibraryImportPrefixName {
+  final String name;
+  final int nameOffset;
+
+  UnlinkedLibraryImportPrefixName({
+    required this.name,
+    required this.nameOffset,
+  });
+
+  factory UnlinkedLibraryImportPrefixName.read(SummaryDataReader reader) {
+    return UnlinkedLibraryImportPrefixName(
+      name: reader.readStringUtf8(),
+      nameOffset: reader.readUInt30(),
+    );
+  }
+
+  void write(BufferedSink sink) {
     sink.writeStringUtf8(name);
     sink.writeUInt30(nameOffset);
   }

pkg/analyzer/lib/src/dart/element/element.dart

@@ -4738,7 +4738,7 @@ class FragmentNameImpl implements FragmentName {
   });
 
   @override
-  int? get nameEnd => nameOffset + name.length;
+  int get nameEnd => nameOffset + name.length;
 }
 
 /// A concrete implementation of a [FunctionElement].
@@ -9152,7 +9152,7 @@ class PrefixFragmentImpl implements PrefixFragment {
   int nameOffset;
 
   @override
-  FragmentNameImpl name2;
+  FragmentNameImpl? name2;
 
   @override
   final bool isDeferred;

pkg/analyzer/lib/src/summary2/bundle_reader.dart

@@ -1270,10 +1270,8 @@ class LibraryReader {
     required LibraryOrAugmentationElementImpl containerLibrary,
     required CompilationUnitElementImpl containerUnit,
   }) {
-    PrefixElementImpl buildElement(String name) {
+    PrefixElementImpl buildElement(String name, Reference reference) {
       // TODO(scheglov): Make reference required.
-      var containerRef = containerUnit.reference!;
-      var reference = containerRef.getChild('@prefix').getChild(name);
       var existing = reference.element;
       if (existing is PrefixElementImpl) {
         return existing;
@@ -1290,13 +1288,15 @@ class LibraryReader {
     switch (kind) {
       case ImportElementPrefixKind.isDeferred:
         var name = _reader.readStringReference();
+        var reference = _readReference();
         return DeferredImportElementPrefixImpl(
-          element: buildElement(name),
+          element: buildElement(name, reference),
         );
       case ImportElementPrefixKind.isNotDeferred:
         var name = _reader.readStringReference();
+        var reference = _readReference();
         return ImportElementPrefixImpl(
-          element: buildElement(name),
+          element: buildElement(name, reference),
         );
       case ImportElementPrefixKind.isNull:
         return null;
@@ -1322,20 +1322,19 @@ class LibraryReader {
     required CompilationUnitElementImpl libraryFragment,
   }) {
     return _reader.readOptionalObject((reader) {
+      var fragmentName = _readFragmentName();
+      var reference = _readReference();
       var name = _reader.readStringReference();
       var isDeferred = _reader.readBool();
       var fragment = PrefixFragmentImpl(
         enclosingFragment: libraryFragment,
         name: name,
         nameOffset: -1,
-        name2: FragmentNameImpl(name: name, nameOffset: -1),
+        name2: fragmentName,
         isDeferred: isDeferred,
       );
 
-      var containerRef = libraryFragment.reference!;
-      var reference = containerRef.getChild('@prefix2').getChild(name);
       var element = reference.element2 as PrefixElementImpl2?;
-
       if (element == null) {
         element = PrefixElementImpl2(
           reference: reference,

pkg/analyzer/lib/src/summary2/bundle_writer.dart

@@ -474,13 +474,15 @@ class BundleWriter {
     LibraryImportElementFlags.write(_sink, element);
   }
 
-  void _writeImportElementPrefix(ImportElementPrefix? prefix) {
-    if (prefix is DeferredImportElementPrefix) {
+  void _writeImportElementPrefix(ImportElementPrefixImpl? prefix) {
+    if (prefix is DeferredImportElementPrefixImpl) {
       _sink.writeByte(ImportElementPrefixKind.isDeferred.index);
       _sink._writeStringReference(prefix.element.name);
-    } else if (prefix is ImportElementPrefix) {
+      _writeReference(prefix.element);
+    } else if (prefix is ImportElementPrefixImpl) {
       _sink.writeByte(ImportElementPrefixKind.isNotDeferred.index);
       _sink._writeStringReference(prefix.element.name);
+      _writeReference(prefix.element);
     } else {
       _sink.writeByte(ImportElementPrefixKind.isNull.index);
     }
@@ -502,6 +504,8 @@ class BundleWriter {
 
   void _writeLibraryImportPrefixFragment(PrefixFragmentImpl? fragment) {
     _sink.writeOptionalObject(fragment, (fragment) {
+      _writeFragmentName(fragment.name2);
+      _writeReference2(fragment.element.reference);
       _sink._writeStringReference(fragment.name);
       _sink.writeBool(fragment.isDeferred);
     });
@@ -676,7 +680,10 @@ class BundleWriter {
 
   /// Write the reference of a non-local element.
   void _writeReference(ElementImpl element) {
-    var reference = element.reference;
+    _writeReference2(element.reference);
+  }
+
+  void _writeReference2(Reference? reference) {
     var index = _references._indexOfReference(reference);
     _sink.writeUInt30(index);
   }

pkg/analyzer/lib/src/summary2/element_builder.dart

@@ -30,7 +30,7 @@ class ElementBuilder extends ThrowingAstVisitor<void> {
   var _partDirectiveIndex = 0;
 
   _EnclosingContext _enclosingContext;
-  var _nextUnnamedId = 0;
+  int _nextUnnamedId = 0;
 
   ElementBuilder({
     required LibraryBuilder libraryBuilder,

pkg/analyzer/lib/src/summary2/informative_data.dart

@@ -674,7 +674,9 @@ class InformativeDataApplier {
 
         if (element.prefix2 case var prefixFragment?) {
           prefixFragment.nameOffset = info.prefixOffset;
-          prefixFragment.name2.nameOffset = info.prefixOffset;
+          if (prefixFragment.name2 case var name?) {
+            name.nameOffset = info.prefixOffset;
+          }
         }
         _applyToCombinators(element.combinators, info.combinators);
       },
@@ -1369,12 +1371,14 @@ class _InfoGenericTypeAlias {
 class _InfoImport {
   final int nameOffset;
   final int prefixOffset;
+  final int? prefixOffset2;
   final List<_InfoCombinator> combinators;
 
   factory _InfoImport(SummaryDataReader reader) {
     return _InfoImport._(
       nameOffset: reader.readUInt30(),
       prefixOffset: reader.readUInt30() - 1,
+      prefixOffset2: reader.readOptionalUInt30(),
       combinators: reader.readTypedList(
         () => _InfoCombinator(reader),
       ),
@@ -1384,6 +1388,7 @@ class _InfoImport {
   _InfoImport._({
     required this.nameOffset,
     required this.prefixOffset,
+    required this.prefixOffset2,
     required this.combinators,
   });
 }
@@ -1477,6 +1482,7 @@ class _InformativeDataWriter {
     sink.writeList2<ImportDirective>(unit.directives, (directive) {
       sink.writeUInt30(directive.importKeyword.offset);
       sink.writeUInt30(1 + (directive.prefix?.offset ?? -1));
+      sink.writeOptionalUInt30(directive.prefix?.token.offsetIfNotEmpty);
       _writeCombinators(directive.combinators);
     });
 

pkg/analyzer/lib/src/summary2/library_builder.dart

@@ -102,6 +102,9 @@ class LibraryBuilder with MacroApplicationsContainer {
   /// The `export` directives that export this library.
   final List<Export> exports = [];
 
+  /// The identifier of the reference used for unnamed fragments.
+  int _nextUnnamedId = 0;
+
   /// The fields that were speculatively created as [ConstFieldElementImpl],
   /// but we want to clear [ConstVariableElement.constantInitializer] for it
   /// if the class will not end up with a `const` constructor. We don't know
@@ -1074,8 +1077,8 @@ class LibraryBuilder with MacroApplicationsContainer {
   }) {
     var importPrefix = state.unlinked.prefix.mapOrNull((unlinked) {
       var prefix = _buildLibraryImportPrefix(
-        name: unlinked.name,
         nameOffset: unlinked.nameOffset,
+        name: unlinked.name,
         containerLibrary: containerLibrary,
         containerUnit: containerUnit,
       );
@@ -1093,8 +1096,7 @@ class LibraryBuilder with MacroApplicationsContainer {
     var prefixFragment = state.unlinked.prefix.mapOrNull((unlinked) {
       return _buildLibraryImportPrefixFragment(
         libraryFragment: containerUnit,
-        name: unlinked.name,
-        nameOffset: unlinked.nameOffset,
+        unlinkedName: unlinked.name,
         isDeferred: unlinked.deferredOffset != null,
       );
     });
@@ -1171,20 +1173,21 @@ class LibraryBuilder with MacroApplicationsContainer {
   }
 
   PrefixElementImpl _buildLibraryImportPrefix({
-    required String name,
     required int nameOffset,
+    required UnlinkedLibraryImportPrefixName? name,
     required LibraryOrAugmentationElementImpl containerLibrary,
     required CompilationUnitElementImpl containerUnit,
   }) {
     // TODO(scheglov): Make reference required.
     var containerRef = containerUnit.reference!;
-    var reference = containerRef.getChild('@prefix').getChild(name);
+    var refName = name?.name ?? '${_nextUnnamedId++}';
+    var reference = containerRef.getChild('@prefix').getChild(refName);
     var existing = reference.element;
     if (existing is PrefixElementImpl) {
       return existing;
     } else {
       var result = PrefixElementImpl(
-        name,
+        name?.name ?? '',
         nameOffset,
         reference: reference,
       );
@@ -1196,23 +1199,28 @@ class LibraryBuilder with MacroApplicationsContainer {
 
   PrefixFragmentImpl _buildLibraryImportPrefixFragment({
     required CompilationUnitElementImpl libraryFragment,
-    required String name,
-    required int nameOffset,
+    required UnlinkedLibraryImportPrefixName? unlinkedName,
     required bool isDeferred,
   }) {
+    FragmentNameImpl? fragmentName;
+    if (unlinkedName != null) {
+      fragmentName = FragmentNameImpl(
+        name: unlinkedName.name,
+        nameOffset: unlinkedName.nameOffset,
+      );
+    }
+
     var fragment = PrefixFragmentImpl(
       enclosingFragment: libraryFragment,
-      name: name,
-      name2: FragmentNameImpl(
-        name: name,
-        nameOffset: nameOffset,
-      ),
-      nameOffset: nameOffset,
+      name: unlinkedName?.name ?? '',
+      nameOffset: unlinkedName?.nameOffset ?? -1,
+      name2: fragmentName,
       isDeferred: isDeferred,
     );
 
     var containerRef = libraryFragment.reference!;
-    var reference = containerRef.getChild('@prefix2').getChild(name);
+    var refName = unlinkedName?.name ?? '${_nextUnnamedId++}';
+    var reference = containerRef.getChild('@prefix2').getChild(refName);
     var element = reference.element2 as PrefixElementImpl2?;
 
     if (element == null) {