analyzer: Privatize ParsedFileState, follow-on work

Work towards #60635

I set out to rename `ParsedFileState.errors` and was concerned it might
be a breaking change, but it turned out that the class could be made
private. As well as ParsedFileStateCache.

But then `getParsed` would return a private type. That could be fixed
by making `getParsed` private.

Also the `parsedFileStateCache` getter seemed suspicious. Turned out it
was only used outside the library in order to clear the cache. So I make
the field private (at which point analyzer told me it should be
final), and added a clearing method.

Change-Id: Iaf30a9cc2a0cfb5c9168db243b7fb2f6c624d8e1
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/433264
Reviewed-by: Konstantin Shcheglov <[email protected]>
Reviewed-by: Paul Berry <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: srawlins

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

@@ -575,7 +575,7 @@ class AnalysisDriver {
   }
 
   void afterPerformWork() {
-    _fsState.parsedFileStateCache.clear();
+    _fsState.clearParsedFileStateCache();
   }
 
   /// Return a [Future] that completes after pending file changes are applied,

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

@@ -590,30 +590,6 @@ class FileState {
     return other is FileState && other.uri == uri;
   }
 
-  /// Returns either new, or cached parsed result for this file.
-  ParsedFileState getParsed({required OperationPerformanceImpl performance}) {
-    var result = _fsState.parsedFileStateCache.get(this);
-    if (result != null) {
-      return result;
-    }
-
-    var diagnosticListener = RecordingDiagnosticListener();
-    var unit = parseCode(
-      code: content,
-      diagnosticListener: diagnosticListener,
-      performance: performance,
-    );
-
-    result = ParsedFileState(
-      code: content,
-      unit: unit,
-      errors: diagnosticListener.diagnostics,
-    );
-    _fsState.parsedFileStateCache.put(this, result);
-
-    return result;
-  }
-
   /// Return a new parsed unresolved [CompilationUnit].
   CompilationUnitImpl parse({
     DiagnosticListener diagnosticListener = DiagnosticListener.NULL_LISTENER,
@@ -680,7 +656,7 @@ class FileState {
     var rawFileState = _fsState.fileContentStrategy.get(path);
     var contentChanged = _fileContent?.contentHash != rawFileState.contentHash;
     _fileContent = rawFileState;
-    _fsState.parsedFileStateCache.remove(this);
+    _fsState._parsedFileStateCache.remove(this);
 
     // Prepare the unlinked bundle key.
     var previousUnlinkedKey = _unlinkedKey;
@@ -826,6 +802,30 @@ class FileState {
     return _fsState.getFileForUri(absoluteUri);
   }
 
+  /// Returns either new, or cached parsed result for this file.
+  _ParsedFileState _getParsed({required OperationPerformanceImpl performance}) {
+    var result = _fsState._parsedFileStateCache.get(this);
+    if (result != null) {
+      return result;
+    }
+
+    var diagnosticListener = RecordingDiagnosticListener();
+    var unit = parseCode(
+      code: content,
+      diagnosticListener: diagnosticListener,
+      performance: performance,
+    );
+
+    result = _ParsedFileState(
+      code: content,
+      unit: unit,
+      diagnostics: diagnosticListener.diagnostics,
+    );
+    _fsState._parsedFileStateCache.put(this, result);
+
+    return result;
+  }
+
   /// Return the unlinked unit, freshly deserialized from bytes,
   /// previously deserialized from bytes, or new.
   AnalysisDriverUnlinkedUnit _getUnlinkedUnit(
@@ -855,7 +855,7 @@ class FileState {
       return result;
     }
 
-    var unit = getParsed(performance: performance).unit;
+    var unit = _getParsed(performance: performance).unit;
 
     return performance.run('compute', (performance) {
       var unlinkedUnit = performance.run('serializeAstUnlinked2', (
@@ -1284,7 +1284,7 @@ class FileSystemState {
   /// in the process of a single analysis operation. But after that, even
   /// if these results are still valid, they are often never used again. So,
   /// currently we clear the cache after each operation.
-  ParsedFileStateCache parsedFileStateCache = ParsedFileStateCache();
+  final _ParsedFileStateCache _parsedFileStateCache = _ParsedFileStateCache();
 
   FileSystemState(
     this._byteStore,
@@ -1340,6 +1340,11 @@ class FileSystemState {
     }
   }
 
+  /// Clears the parsed file state cache.
+  void clearParsedFileStateCache() {
+    _parsedFileStateCache.clear();
+  }
+
   /// Collected files that transitively reference a file with the [path].
   /// These files are potentially affected by the change.
   void collectAffected(String path, Set<FileState> affected) {
@@ -2105,39 +2110,6 @@ class LibraryResolutionResult {
   LibraryResolutionResult({required this.requirements, required this.bytes});
 }
 
-class ParsedFileState {
-  final String code;
-  final CompilationUnitImpl unit;
-  // TODO(srawlins): Rename to `diagnostics`.
-  final List<Diagnostic> errors;
-
-  ParsedFileState({
-    required this.code,
-    required this.unit,
-    required this.errors,
-  });
-}
-
-class ParsedFileStateCache {
-  final Map<FileState, ParsedFileState> _map = Map.identity();
-
-  void clear() {
-    _map.clear();
-  }
-
-  ParsedFileState? get(FileState file) {
-    return _map[file];
-  }
-
-  void put(FileState file, ParsedFileState result) {
-    _map[file] = result;
-  }
-
-  void remove(FileState file) {
-    _map.remove(file);
-  }
-}
-
 /// The file has `part of` directive.
 sealed class PartFileKind extends FileKind {
   PartFileKind({required super.file});
@@ -2427,6 +2399,38 @@ class _LibraryNameToFiles {
   }
 }
 
+class _ParsedFileState {
+  final String code;
+  final CompilationUnitImpl unit;
+  final List<Diagnostic> diagnostics;
+
+  _ParsedFileState({
+    required this.code,
+    required this.unit,
+    required this.diagnostics,
+  });
+}
+
+class _ParsedFileStateCache {
+  final Map<FileState, _ParsedFileState> _map = Map.identity();
+
+  void clear() {
+    _map.clear();
+  }
+
+  _ParsedFileState? get(FileState file) {
+    return _map[file];
+  }
+
+  void put(FileState file, _ParsedFileState result) {
+    _map[file] = result;
+  }
+
+  void remove(FileState file) {
+    _map.remove(file);
+  }
+}
+
 extension on List<DirectiveState> {
   void disposeAll() {
     for (var directive in this) {

pkg/analyzer/lib/src/dart/micro/resolve_file.dart

@@ -679,7 +679,7 @@ class FileResolver {
   }
 
   void _clearFileSystemStateParsedCache() {
-    fsState?.parsedFileStateCache.clear();
+    fsState?.clearParsedFileStateCache();
   }
 
   /// Make sure that [fsState], [contextObjects], and [libraryContext] are