[macros] JSON benchmarks, JsonBuffer experiment. (#3883)

Author: davidmorgan

working/macros/dart_model/README.md

@@ -21,7 +21,7 @@ as a library;\
 The "macros" referred to in this exploration are independent of the in-progress
 macro implementation, hence the "scare quotes".
 
-## Benchmarks
+## End to End Benchmarks
 
 `testing/benchmark` is a tool to assist in benchmarking, it creates codebases
 of the specified size and codegen strategy.
@@ -65,3 +65,7 @@ $ dart bin/main.dart
 # files to see how the analyzer responds; you can watch the macro host terminal
 # to see when it is rewriting augmentation files.
 ```
+
+## Serialization Benchmarks
+
+`testing/json_benchmark` is benchmarking related to JSON serialization.

working/macros/dart_model/testing/json_benchmark/bin/main.dart

@@ -0,0 +1,3 @@
+import 'package:json_benchmark/json_benchmark.dart';
+
+Future<void> main() async => JsonBenchmark().run();

working/macros/dart_model/testing/json_benchmark/lib/json_benchmark.dart

@@ -0,0 +1,97 @@
+import 'dart:io';
+
+import 'json_buffer_subject.dart';
+import 'json_subject.dart';
+
+class JsonBenchmark {
+  Future<void> run() async {
+    final jsonSubject = JsonSubject();
+
+    print('Subject,Scenario,Data size/bytes,Time per/ms');
+    for (final subject in [
+      JsonBufferSubject(),
+      JsonBufferSubject(),
+      JsonBufferSubject(),
+      JsonBufferSubject(),
+      JsonBufferSubject(), /*JsonSubject()*/
+    ]) {
+      for (final size in [256]) {
+        final neutralData = jsonSubject.createData(libraryCount: size);
+        final subjectData = subject.deepCopyIn(neutralData);
+        final byteData = subject.serialize(subjectData);
+        final byteLength = byteData.length;
+
+        await benchmark(subject.name, 'create', byteLength,
+            () => subject.createData(libraryCount: size));
+        await benchmark(subject.name, 'deepCopyIn', byteLength,
+            () => subject.deepCopyIn(neutralData));
+        await benchmark(subject.name, 'serialize', byteLength,
+            () => subject.serialize(subjectData));
+        await benchmark(subject.name, 'writeSync', byteLength,
+            () => File('/tmp/benchmark').writeAsBytesSync(byteData));
+        await benchmark(
+            subject.name,
+            'copySerializeWrite',
+            byteLength,
+            () => File('/tmp/benchmark').writeAsBytesSync(
+                subject.serialize(subject.deepCopyIn(neutralData))));
+        await benchmark(
+            subject.name,
+            'createSerializeWrite',
+            byteLength,
+            () => File('/tmp/benchmark').writeAsBytesSync(
+                subject.serialize(subject.createData(libraryCount: size))));
+
+        await benchmark(
+            subject.name, 'process', byteLength, () => process(subjectData));
+        await benchmark(subject.name, 'deepCopyOut', byteLength,
+            () => subject.deepCopyOut(subjectData));
+        await benchmark(subject.name, 'readSync', byteLength,
+            () => File('/tmp/benchmark').readAsBytesSync());
+        await benchmark(subject.name, 'deserialize', byteLength,
+            () => subject.deserialize(byteData));
+        await benchmark(
+            subject.name,
+            'readDeserializeCopy',
+            byteLength,
+            () => subject.deepCopyOut(
+                subject.deserialize(File('/tmp/benchmark').readAsBytesSync())));
+        await benchmark(
+            subject.name,
+            'readDeserializeProcess',
+            byteLength,
+            () => process(
+                subject.deserialize(File('/tmp/benchmark').readAsBytesSync())));
+      }
+    }
+  }
+
+  int process(Map<String, Object?> data) {
+    var result = 0;
+    for (final entry in data.entries) {
+      final key = entry.key;
+      result ^= key.hashCode;
+      var value = entry.value;
+      if (value is Map<String, Object?>) {
+        result ^= process(value);
+      } else {
+        result ^= value.hashCode;
+      }
+    }
+    return result;
+  }
+
+  Future<void> benchmark(String subjectName, String scenarioName, int length,
+      Function subject) async {
+    final repetitions = 100;
+    for (var i = 0; i != repetitions; ++i) {
+      subject();
+    }
+    final stopwatch = Stopwatch()..start();
+    for (var i = 0; i != repetitions; ++i) {
+      subject();
+    }
+    final elapsed = stopwatch.elapsedMilliseconds;
+    print('$subjectName,$scenarioName,$length,${elapsed / repetitions}');
+  }
+}