[pigeon] Switch Indent class to manage all writes with a StringBuffer

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 26.1.10
+
+* Dramatically reduces the number of File write operations sent to the operating
+  system during code-generation. This improves performance of IDEs and the Dart
+  analysis server.
+
 ## 26.1.9
 
 * [dart] Reduces much duplication in reply-handling code.

packages/pigeon/lib/src/ast_generator.dart

@@ -7,7 +7,7 @@ import 'generator_tools.dart';
 
 /// Writes the AST representation of [root] to [sink].
 void generateAst(Root root, StringSink sink) {
-  final indent = Indent(sink);
+  final indent = Indent();
   final output = root.toString();
   var isFirst = true;
   for (final int ch in output.runes) {
@@ -26,4 +26,5 @@ void generateAst(Root root, StringSink sink) {
     indent.add(chStr);
   }
   indent.addln('');
+  sink.write(indent.toString());
 }

packages/pigeon/lib/src/dart/dart_generator.dart

@@ -774,9 +774,9 @@ final BinaryMessenger? ${varNamePrefix}binaryMessenger;
               ])
               ..body = cb.Block.of(
                 cb.Block((cb.BlockBuilder builder) {
-                  final messageHandlerSink = StringBuffer();
+                  final messageHandlerIndent = Indent();
                   writeFlutterMethodMessageHandler(
-                    Indent(messageHandlerSink),
+                    messageHandlerIndent,
                     name: 'removeStrongReferenceName',
                     parameters: <Parameter>[
                       Parameter(
@@ -805,7 +805,7 @@ final BinaryMessenger? ${varNamePrefix}binaryMessenger;
                         },
                   );
                   builder.statements.add(
-                    cb.Code(messageHandlerSink.toString()),
+                    cb.Code(messageHandlerIndent.toString()),
                   );
                 }).statements,
               );
@@ -825,9 +825,9 @@ final BinaryMessenger? ${varNamePrefix}binaryMessenger;
                 ),
               )
               ..body = cb.Block((cb.BlockBuilder builder) {
-                final messageCallSink = StringBuffer();
+                final messageCallIndent = Indent();
                 writeHostMethodMessageCall(
-                  Indent(messageCallSink),
+                  messageCallIndent,
                   addSuffixVariable: false,
                   channelName: makeRemoveStrongReferenceChannelName(
                     dartPackageName,
@@ -844,7 +844,7 @@ final BinaryMessenger? ${varNamePrefix}binaryMessenger;
                   returnType: const TypeDeclaration.voidDeclaration(),
                 );
                 builder.statements.addAll(<cb.Code>[
-                  cb.Code(messageCallSink.toString()),
+                  cb.Code(messageCallIndent.toString()),
                 ]);
               });
           }),
@@ -859,16 +859,16 @@ final BinaryMessenger? ${varNamePrefix}binaryMessenger;
                 '/// This is typically called after a hot restart.',
               ])
               ..body = cb.Block((cb.BlockBuilder builder) {
-                final messageCallSink = StringBuffer();
+                final messageCallIndent = Indent();
                 writeHostMethodMessageCall(
-                  Indent(messageCallSink),
+                  messageCallIndent,
                   addSuffixVariable: false,
                   channelName: makeClearChannelName(dartPackageName),
                   parameters: <Parameter>[],
                   returnType: const TypeDeclaration.voidDeclaration(),
                 );
                 builder.statements.addAll(<cb.Code>[
-                  cb.Code(messageCallSink.toString()),
+                  cb.Code(messageCallIndent.toString()),
                 ]);
               });
           }),
@@ -1029,7 +1029,7 @@ final BinaryMessenger? ${varNamePrefix}binaryMessenger;
     required String dartPackageName,
     required String dartOutputPackageName,
   }) {
-    final indent = Indent(sink);
+    final indent = Indent();
     final String sourceOutPath = generatorOptions.dartOut ?? '';
     final String testOutPath = generatorOptions.testOut ?? '';
     _writeTestPrologue(generatorOptions, root, indent);
@@ -1079,6 +1079,7 @@ final BinaryMessenger? ${varNamePrefix}binaryMessenger;
         );
       }
     }
+    sink.write(indent.toString());
   }
 
   /// Writes file header to sink.

packages/pigeon/lib/src/dart/proxy_api_generator_helper.dart

@@ -461,9 +461,9 @@ Iterable<cb.Constructor> constructors(
             const cb.Code('super.${classMemberNamePrefix}detached()'),
         ])
         ..body = cb.Block((cb.BlockBuilder builder) {
-          final messageCallSink = StringBuffer();
+          final messageCallIndent = Indent();
           DartGenerator.writeHostMethodMessageCall(
-            Indent(messageCallSink),
+            messageCallIndent,
             addSuffixVariable: false,
             channelName: channelName,
             insideAsyncMethod: false,
@@ -492,7 +492,7 @@ Iterable<cb.Constructor> constructors(
             cb.Code(
               'final BinaryMessenger? ${varNamePrefix}binaryMessenger = ${binaryMessengerParameter.name};',
             ),
-            cb.Code(messageCallSink.toString()),
+            cb.Code(messageCallIndent.toString()),
           ]);
         });
     });
@@ -792,10 +792,10 @@ cb.Method setUpMessageHandlerMethod({
         ],
         if (hasCallbackConstructor)
           ...cb.Block((cb.BlockBuilder builder) {
-            final messageHandlerSink = StringBuffer();
+            final messageHandlerIndent = Indent();
             const methodName = '${classMemberNamePrefix}newInstance';
             DartGenerator.writeFlutterMethodMessageHandler(
-              Indent(messageHandlerSink),
+              messageHandlerIndent,
               name: methodName,
               parameters: <Parameter>[
                 Parameter(
@@ -844,13 +844,13 @@ cb.Method setUpMessageHandlerMethod({
                         ')';
                   },
             );
-            builder.statements.add(cb.Code(messageHandlerSink.toString()));
+            builder.statements.add(cb.Code(messageHandlerIndent.toString()));
           }).statements,
         for (final Method method in flutterMethods)
           ...cb.Block((cb.BlockBuilder builder) {
-            final messageHandlerSink = StringBuffer();
+            final messageHandlerIndent = Indent();
             DartGenerator.writeFlutterMethodMessageHandler(
-              Indent(messageHandlerSink),
+              messageHandlerIndent,
               name: method.name,
               parameters: <Parameter>[
                 Parameter(
@@ -885,7 +885,7 @@ cb.Method setUpMessageHandlerMethod({
                     return '($methodName ?? ${safeArgumentNames.first}.$methodName)$nullability.call(${safeArgumentNames.join(',')})';
                   },
             );
-            builder.statements.add(cb.Code(messageHandlerSink.toString()));
+            builder.statements.add(cb.Code(messageHandlerIndent.toString()));
           }).statements,
       ]),
   );
@@ -913,9 +913,9 @@ Iterable<cb.Method> attachedFieldMethods(
         ..static = field.isStatic
         ..returns = cb.refer(type)
         ..body = cb.Block((cb.BlockBuilder builder) {
-          final messageCallSink = StringBuffer();
+          final messageCallIndent = Indent();
           DartGenerator.writeHostMethodMessageCall(
-            Indent(messageCallSink),
+            messageCallIndent,
             addSuffixVariable: false,
             channelName: makeChannelNameWithStrings(
               apiName: apiName,
@@ -968,7 +968,7 @@ Iterable<cb.Method> attachedFieldMethods(
               ),
             ],
             const cb.Code('() async {'),
-            cb.Code(messageCallSink.toString()),
+            cb.Code(messageCallIndent.toString()),
             const cb.Code('}();'),
             const cb.Code('return $instanceName;'),
           ]);
@@ -1023,9 +1023,9 @@ Iterable<cb.Method> hostMethods(
           ],
         ])
         ..body = cb.Block((cb.BlockBuilder builder) {
-          final messageCallSink = StringBuffer();
+          final messageCallIndent = Indent();
           DartGenerator.writeHostMethodMessageCall(
-            Indent(messageCallSink),
+            messageCallIndent,
             addSuffixVariable: false,
             channelName: makeChannelNameWithStrings(
               apiName: apiName,
@@ -1073,7 +1073,7 @@ Iterable<cb.Method> hostMethods(
             const cb.Code(
               'final BinaryMessenger? ${varNamePrefix}binaryMessenger = ${classMemberNamePrefix}binaryMessenger;',
             ),
-            cb.Code(messageCallSink.toString()),
+            cb.Code(messageCallIndent.toString()),
           ]);
         }),
     );

packages/pigeon/lib/src/generator.dart

@@ -40,7 +40,7 @@ abstract class StructuredGenerator<T extends InternalOptions>
     StringSink sink, {
     required String dartPackageName,
   }) {
-    final indent = Indent(sink);
+    final indent = Indent();
 
     writeFilePrologue(
       generatorOptions,
@@ -117,6 +117,8 @@ abstract class StructuredGenerator<T extends InternalOptions>
       indent,
       dartPackageName: dartPackageName,
     );
+
+    sink.write(indent.toString());
   }
 
   /// Adds specified headers to [indent].

packages/pigeon/lib/src/generator_tools.dart

@@ -15,7 +15,7 @@ import 'generator.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '26.1.9';
+const String pigeonVersion = '26.1.10';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
@@ -31,13 +31,13 @@ String readStdin() {
 /// True if the generator line number should be printed out at the end of newlines.
 bool debugGenerators = false;
 
-/// A helper class for managing indentation, wrapping a [StringSink].
+/// A helper class for managing indentation, wrapping a [StringBuffer].
 class Indent {
-  /// Constructor which takes a [StringSink] which this [Indent] will wrap.
-  Indent(this._sink);
-
   int _count = 0;
-  final StringSink _sink;
+  final StringBuffer _buffer = StringBuffer();
+
+  @override
+  String toString() => _buffer.toString();
 
   /// String used for newlines (ex "\n").
   String get newline {
@@ -119,13 +119,13 @@ class Indent {
     int nestCount = 1,
   }) {
     if (begin != null) {
-      _sink.write(begin + newline);
+      _buffer.write(begin + newline);
     }
     nest(nestCount, func);
     if (end != null && end.isNotEmpty) {
-      _sink.write(str() + end);
+      _buffer.write(str() + end);
       if (addTrailingNewline) {
-        _sink.write(newline);
+        _buffer.write(newline);
       }
     }
   }
@@ -159,31 +159,31 @@ class Indent {
   /// Add [text] with indentation and a newline.
   void writeln(String text) {
     if (text.isEmpty) {
-      _sink.write(newline);
+      _buffer.write(newline);
     } else {
-      _sink.write(str() + text + newline);
+      _buffer.write(str() + text + newline);
     }
   }
 
   /// Add [text] with indentation.
   void write(String text) {
-    _sink.write(str() + text);
+    _buffer.write(str() + text);
   }
 
   /// Add [text] with a newline.
   void addln(String text) {
-    _sink.write(text + newline);
+    _buffer.write(text + newline);
   }
 
   /// Just adds [text].
   void add(String text) {
-    _sink.write(text);
+    _buffer.write(text);
   }
 
   /// Adds [lines] number of newlines.
   void newln([int lines = 1]) {
     for (; lines > 0; lines--) {
-      _sink.write(newline);
+      _buffer.write(newline);
     }
   }
 }

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 26.1.9 # This must match the version in lib/src/generator_tools.dart
+version: 26.1.10 # This must match the version in lib/src/generator_tools.dart
 
 environment:
   sdk: ^3.9.0

packages/pigeon/test/generator_tools_test.dart

@@ -500,16 +500,15 @@ void main() {
   });
 
   test('Indent.format trims indentation', () {
-    final buffer = StringBuffer();
-    final indent = Indent(buffer);
+    final indent = Indent();
 
     indent.format('''
       void myMethod() {
 
         print('hello');
       }''');
 
-    expect(buffer.toString(), '''
+    expect(indent.toString(), '''
 void myMethod() {
 
   print('hello');