[Do not submit] Add model digest

pkgs/dart_model/lib/src/dart_model.g.dart

@@ -1,6 +1,10 @@
 // This file is generated. To make changes edit tool/dart_model_generator
 // then run from the repo root: dart tool/dart_model_generator/bin/main.dart
 
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'dart:typed_data';
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'package:crypto/crypto.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports
 import 'package:dart_model/src/deep_cast_map.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports
@@ -251,6 +255,11 @@ extension type Model.fromJson(Map<String, Object?> node) implements Object {
           Scope.createGrowableMap(),
           types,
         ));
+// A digest of all the bytes in the current buffer.
+  Digest get digest => md5.convert(switch (node) {
+        MapInBuffer mapInBuffer => mapInBuffer.buffer.serialize(),
+        _ => (JsonBufferBuilder()..map.addAll(node)).serialize(),
+      });
 
   /// Libraries by URI.
   Map<String, Library> get uris =>

pkgs/dart_model/lib/src/json_buffer/iterables.dart

@@ -42,7 +42,7 @@ class _IteratorFunctionIterable<T> extends Iterable<T> {
 
 /// A `Map` in a `JsonBufferBuilder`.
 abstract interface class MapInBuffer {
-  /// The buffer backing this `Map`.
+  /// The buffer backing this [Map].
   JsonBufferBuilder get buffer;
 
   /// The `Map` that contains this value, or `null` if this value has not been

pkgs/dart_model/lib/src/macro_metadata.g.dart

@@ -1,6 +1,10 @@
 // This file is generated. To make changes edit tool/dart_model_generator
 // then run from the repo root: dart tool/dart_model_generator/bin/main.dart
 
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'dart:typed_data';
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'package:crypto/crypto.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports
 import 'package:dart_model/src/deep_cast_map.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports

pkgs/dart_model/pubspec.yaml

@@ -12,6 +12,7 @@ environment:
 
 dependencies:
   collection: ^1.19.0
+  crypto: ^3.0.6
 
 dev_dependencies:
   benchmark_harness: ^2.2.2

pkgs/dart_model/test/model_test.dart

@@ -201,6 +201,11 @@ void main() {
       expect(copiedModel.qualifiedNameOf(member.node), null);
       expect(model.qualifiedNameOf(copiedMember.node), null);
     });
+
+    test('can produce and compare digests for buffer and SDK maps', () {
+      final copiedModel = Model.fromJson(_copyMap(model.node));
+      expect(model.digest, copiedModel.digest);
+    });
   });
 
   group('QualifiedName', () {

pkgs/macro_service/lib/src/handshake.g.dart

@@ -1,6 +1,10 @@
 // This file is generated. To make changes edit tool/dart_model_generator
 // then run from the repo root: dart tool/dart_model_generator/bin/main.dart
 
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'dart:typed_data';
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'package:crypto/crypto.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports
 import 'package:dart_model/src/deep_cast_map.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports

pkgs/macro_service/lib/src/macro_service.g.dart

@@ -1,6 +1,10 @@
 // This file is generated. To make changes edit tool/dart_model_generator
 // then run from the repo root: dart tool/dart_model_generator/bin/main.dart
 
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'dart:typed_data';
+// ignore: implementation_imports,unused_import,prefer_relative_imports
+import 'package:crypto/crypto.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports
 import 'package:dart_model/src/dart_model.g.dart';
 // ignore: implementation_imports,unused_import,prefer_relative_imports

tool/dart_model_generator/lib/definitions.dart

@@ -183,16 +183,21 @@ static Protocol handshakeProtocol = Protocol(
                   description: 'The named parameters of this member, '
                       'if it has them.'),
             ]),
-        Definition.clazz('Model',
-            description: 'Partial model of a corpus of Dart source code.',
-            createInBuffer: true,
-            properties: [
-              Property('uris',
-                  type: 'Map<Library>', description: 'Libraries by URI.'),
-              Property('types',
-                  type: 'TypeHierarchy',
-                  description: 'The resolved static type hierarchy.'),
-            ]),
+        Definition.clazz(
+          'Model',
+          description: 'Partial model of a corpus of Dart source code.',
+          createInBuffer: true,
+          properties: [
+            Property('uris',
+                type: 'Map<Library>', description: 'Libraries by URI.'),
+            Property('types',
+                type: 'TypeHierarchy',
+                description: 'The resolved static type hierarchy.'),
+          ],
+          extraCode: '// A digest of all the bytes in the current buffer.\n'
+              'Digest get digest => '
+              'md5.convert((node as MapInBuffer).buffer.serialize());',
+        ),
         Definition.clazz('NamedFunctionTypeParameter',
             description:
                 'A resolved named parameter as part of a [FunctionTypeDesc].',

tool/dart_model_generator/lib/generate_dart_model.dart

@@ -65,6 +65,8 @@ class GenerationContext {
         lookupDeclaringSchema(typeName),
     }.nonNulls;
     return ([
+      "import 'dart:typed_data';",
+      "import 'package:crypto/crypto.dart';",
       "import 'package:dart_model/src/json_buffer/json_buffer_builder.dart';",
       "import 'package:dart_model/src/deep_cast_map.dart';",
       "import 'package:dart_model/src/scopes.dart';",