Cache parsed library results. (#1307)

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+# 8.9.2
+
+- Improve build performance when there are lots of `built_value` classes.
+
 # 8.9.1
 
 - Fix for new warning about `operator==` param type.

built_value_generator/lib/built_value_generator.dart

@@ -5,8 +5,9 @@
 import 'package:analyzer/dart/element/element.dart';
 import 'package:build/build.dart';
 import 'package:built_value_generator/src/enum_source_library.dart';
-import 'package:built_value_generator/src/value_source_class.dart';
+import 'package:built_value_generator/src/parsed_library_results.dart';
 import 'package:built_value_generator/src/serializer_source_library.dart';
+import 'package:built_value_generator/src/value_source_class.dart';
 import 'package:source_gen/source_gen.dart';
 
 /// Generator for Enum Class and Built Values.
@@ -18,14 +19,16 @@ class BuiltValueGenerator extends Generator {
 
   @override
   Future<String?> generate(LibraryReader library, BuildStep buildStep) async {
+    var parsedLibraryResults = ParsedLibraryResults();
+
     // Workaround for https://github.com/google/built_value.dart/issues/941.
     LibraryElement libraryElement;
     var attempts = 0;
     while (true) {
       try {
         libraryElement = await buildStep.resolver.libraryFor(
             await buildStep.resolver.assetIdForElement(library.element));
-        libraryElement.session.getParsedLibraryByElement(libraryElement);
+        parsedLibraryResults.parsedLibraryResultOrThrowingMock(libraryElement);
         break;
       } catch (_) {
         ++attempts;
@@ -38,9 +41,11 @@ class BuiltValueGenerator extends Generator {
 
     var result = StringBuffer();
     try {
-      final enumCode = EnumSourceLibrary(libraryElement).generateCode();
+      final enumCode = EnumSourceLibrary(parsedLibraryResults, libraryElement)
+          .generateCode();
       if (enumCode != null) result.writeln(enumCode);
-      final serializerSourceLibrary = SerializerSourceLibrary(libraryElement);
+      final serializerSourceLibrary =
+          SerializerSourceLibrary(parsedLibraryResults, libraryElement);
       if (serializerSourceLibrary.needsBuiltJson ||
           serializerSourceLibrary.hasSerializers) {
         result.writeln(serializerSourceLibrary.generateCode());
@@ -64,7 +69,8 @@ class BuiltValueGenerator extends Generator {
     for (var element in libraryElement.units.expand((unit) => unit.classes)) {
       if (ValueSourceClass.needsBuiltValue(element)) {
         try {
-          result.writeln(ValueSourceClass(element).generateCode());
+          result.writeln(
+              ValueSourceClass(parsedLibraryResults, element).generateCode());
         } catch (e, st) {
           result.writeln(_error(e));
           log.severe('Error in BuiltValueGenerator for $element.', e, st);

built_value_generator/lib/src/dart_types.dart

@@ -6,6 +6,7 @@ import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/nullability_suffix.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:built_collection/built_collection.dart';
+import 'package:built_value_generator/src/parsed_library_results.dart';
 import 'package:built_value_generator/src/value_source_class.dart';
 
 BuiltSet<String> _builtCollectionNames = BuiltSet<String>([
@@ -17,13 +18,18 @@ BuiltSet<String> _builtCollectionNames = BuiltSet<String>([
 ]);
 
 class DartTypes {
-  static bool needsNestedBuilder(DartType type) {
-    return isInstantiableBuiltValue(type) || isBuiltCollection(type);
+  static bool needsNestedBuilder(
+      ParsedLibraryResults parsedLibraryResults, DartType type) {
+    return isInstantiableBuiltValue(parsedLibraryResults, type) ||
+        isBuiltCollection(type);
   }
 
-  static bool isInstantiableBuiltValue(DartType type) {
+  static bool isInstantiableBuiltValue(
+      ParsedLibraryResults parsedLibraryResults, DartType type) {
     return isBuiltValue(type) &&
-        ValueSourceClass(type.element as ClassElement).settings.instantiable;
+        ValueSourceClass(parsedLibraryResults, type.element as ClassElement)
+            .settings
+            .instantiable;
   }
 
   static bool isBuiltValue(DartType type) =>

built_value_generator/lib/src/enum_source_class.dart

@@ -8,9 +8,9 @@ import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
-import 'package:built_value_generator/src/analyzer.dart';
 import 'package:built_value_generator/src/dart_types.dart';
 import 'package:built_value_generator/src/enum_source_field.dart';
+import 'package:built_value_generator/src/parsed_library_results.dart';
 import 'package:built_value_generator/src/strings.dart';
 import 'package:collection/collection.dart'
     show IterableExtension, IterableNullableExtension;
@@ -21,16 +21,19 @@ part 'enum_source_class.g.dart';
 
 abstract class EnumSourceClass
     implements Built<EnumSourceClass, EnumSourceClassBuilder> {
+  ParsedLibraryResults get parsedLibraryResults;
+
   InterfaceElement get element;
 
-  factory EnumSourceClass(
-          ParsedLibraryResult parsedLibrary, InterfaceElement element) =>
-      _$EnumSourceClass._(element: element);
+  factory EnumSourceClass(ParsedLibraryResults parsedLibraryResults,
+          InterfaceElement element) =>
+      _$EnumSourceClass._(
+          parsedLibraryResults: parsedLibraryResults, element: element);
   EnumSourceClass._();
 
   @memoized
   ParsedLibraryResult get parsedLibrary =>
-      parsedLibraryResultOrThrowingMock(element.library);
+      parsedLibraryResults.parsedLibraryResultOrThrowingMock(element.library);
 
   @memoized
   String get name => element.name;

built_value_generator/lib/src/enum_source_library.dart

@@ -8,24 +8,27 @@ import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
-import 'package:built_value_generator/src/analyzer.dart';
 import 'package:built_value_generator/src/enum_source_class.dart';
 import 'package:built_value_generator/src/library_elements.dart';
+import 'package:built_value_generator/src/parsed_library_results.dart';
 import 'package:source_gen/source_gen.dart';
 
 part 'enum_source_library.g.dart';
 
 abstract class EnumSourceLibrary
     implements Built<EnumSourceLibrary, EnumSourceLibraryBuilder> {
+  ParsedLibraryResults get parsedLibraryResults;
   LibraryElement get element;
 
-  factory EnumSourceLibrary(LibraryElement element) =>
-      _$EnumSourceLibrary._(element: element);
+  factory EnumSourceLibrary(
+          ParsedLibraryResults parsedLibraryResults, LibraryElement element) =>
+      _$EnumSourceLibrary._(
+          parsedLibraryResults: parsedLibraryResults, element: element);
   EnumSourceLibrary._();
 
   @memoized
   ParsedLibraryResult get parsedLibrary =>
-      parsedLibraryResultOrThrowingMock(element.library);
+      parsedLibraryResults.parsedLibraryResultOrThrowingMock(element.library);
 
   @memoized
   String get name => element.name;
@@ -42,7 +45,7 @@ abstract class EnumSourceLibrary
 
     for (var classElement in LibraryElements.getClassElements(element)) {
       if (EnumSourceClass.needsEnumClass(classElement)) {
-        result.add(EnumSourceClass(parsedLibrary, classElement));
+        result.add(EnumSourceClass(parsedLibraryResults, classElement));
       }
     }
     return result.build();

built_value_generator/lib/src/parsed_library_results.dart

@@ -0,0 +1,33 @@
+// Copyright (c) 2021, Google Inc. 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:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/dart/element/element.dart';
+
+/// Caches parsed library results across one generation.
+///
+/// Substitutes a "throwing mock" if no parsed library is available.
+class ParsedLibraryResults {
+  final Map<Uri, ParsedLibraryResult> _results = {};
+
+  ParsedLibraryResult parsedLibraryResultOrThrowingMock(
+      LibraryElement element) {
+    var uri = element.source.uri;
+    return _results[uri] ??= _parsedLibraryResultOrThrowingMock(element);
+  }
+
+  ParsedLibraryResult _parsedLibraryResultOrThrowingMock(
+      LibraryElement element) {
+    var result = element.session.getParsedLibraryByElement(element);
+    if (result is ParsedLibraryResult) {
+      return result;
+    }
+    return _ParsedLibraryResultMock();
+  }
+}
+
+class _ParsedLibraryResultMock implements ParsedLibraryResult {
+  @override
+  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}