feat: implement annotations

cherrypick_generator/lib/cherrypick_generator.dart

@@ -0,0 +1,8 @@
+/// Support for doing something awesome.
+///
+/// More dartdocs go here.
+library;
+
+export 'src/cherrypick_generator_base.dart';
+
+// TODO: Export any libraries intended for clients of this package.

cherrypick_generator/lib/src/cherrypick_generator_base.dart

@@ -0,0 +1,6 @@
+// TODO: Put public facing types in this file.
+
+/// Checks if you are awesome. Spoiler: you are.
+class Awesome {
+  bool get isAwesome => true;
+}

cherrypick_generator/lib/src/inject_generator.dart

@@ -0,0 +1,28 @@
+import 'dart:async';
+import 'package:build/build.dart';
+import 'package:source_gen/source_gen.dart';
+import 'package:cherrypick_annotations/cherrypick_annotations.dart';
+import 'package:analyzer/dart/element/element.dart';
+
+class InjectGenerator extends GeneratorForAnnotation<Inject> {
+  @override
+  FutureOr<String> generateForAnnotatedElement(
+      Element element, ConstantReader annotation, BuildStep buildStep) {
+    if (element is! FieldElement) {
+      throw InvalidGenerationSourceError(
+        'Генератор не может работать с `${element.name}`.',
+      );
+    }
+
+    final named = annotation.peek('named')?.stringValue;
+    final resolveSnippet = named == null
+        ? 'CherryPickProvider.of(context).openRootScope().resolve<${element.type}>()'
+        : 'CherryPickProvider.of(context).openRootScope().resolve<${element.type}>(named: \'$named\')';
+
+    return '''
+void _initState(BuildContext context) {
+  ${element.name} = $resolveSnippet;
+}
+''';
+  }
+}