AspectD: An Effective AOP Solution for Flutter — Open Sourced by Alibaba Xianyu Tech Team

Background

AspectD: Dart-Oriented AOP Framework

Design Details

Typical AOP Scenarios

aop.dartimport 'package:example/main.dart' as app;
import 'aop_impl.dart';
void main()=> app.main();aop_impl.dartimport 'package:aspectd/aspectd.dart';@Aspect()
@pragma("vm:entry-point")
class ExecuteDemo {
@pragma("vm:entry-point")
ExecuteDemo();
@Execute("package:example/main.dart", "_MyHomePageState", "-_incrementCounter")
@pragma("vm:entry-point")
void _incrementCounter(PointCut pointcut) {
pointcut.proceed();
print('KWLM called!') ;
}
}

Developer-Oriented API design

Design of PointCut

@Call("package:app/calculator.dart","Calculator","-getCurTime")
@pragma('vm:entry-point')
class PointCut {
final Map<dynamic> sourceInfos;
final Object target;
final String function;
final String stubId;
final List<dynamic> positionalParams;
final Map<dynamic, dynamic> namedParams;
@pragma('vm:entry-point')
PointCut(this.sourceInfos, this.target, this.function, this.stubId,this.positionalParams, this.namedParams);
@pragma('vm:entry-point')
Object proceed(){
return null;
}
}

Design of Advice

@pragma("vm:entry-point")
Future<String> getCurTime(PointCut pointcut) async{
...
return result;
}

Design of Aspect

@Aspect()
@pragma("vm:entry-point")
class ExecuteDemo {
@pragma("vm:entry-point")
ExecuteDemo();
...
}

Compilation of AOP code

Contain the Main Entry in the Original Project

Compilation in Debug Mode

Compilation in Release Mode

Dill Operation

Structure of Dill

dart bin/dump_kernel.dart /Users/kylewong/Codes/AOP/aspectd/example/aop/build/app.dill /Users/kylewong/Codes/AOP/aspectd/example/aop/build/app.dill.txt

Transformation of Dill

@override
MethodInvocation visitMethodInvocation(MethodInvocation methodInvocation) {
methodInvocation.transformChildren(this);
Node node = methodInvocation.interfaceTargetReference?.node;
String uniqueKeyForMethod = null;
if (node is Procedure) {
Procedure procedure = node;
Class cls = procedure.parent as Class;
String procedureImportUri = cls.reference.canonicalName.parent.name;
uniqueKeyForMethod = AspectdItemInfo.uniqueKeyForMethod(
procedureImportUri, cls.name, methodInvocation.name.name, false, null);
}
else if(node == null) {
String importUri = methodInvocation?.interfaceTargetReference?.canonicalName?.reference?.canonicalName?.nonRootTop?.name;
String clsName = methodInvocation?.interfaceTargetReference?.canonicalName?.parent?.parent?.name;
String methodName = methodInvocation?.interfaceTargetReference?.canonicalName?.name;
uniqueKeyForMethod = AspectdItemInfo.uniqueKeyForMethod(
importUri, clsName, methodName, false, null);
}
if(uniqueKeyForMethod ! = null) {
AspectdItemInfo aspectdItemInfo = _aspectdInfoMap[uniqueKeyForMethod];
if (aspectdItemInfo?.mode == AspectdMode.Call &&
! _transformedInvocationSet.contains(methodInvocation) && AspectdUtils.checkIfSkipAOP(aspectdItemInfo, _curLibrary) == false) {
return transformInstanceMethodInvocation(
methodInvocation, aspectdItemInfo);
}
}
return methodInvocation;
}

Syntax Supported by AspectD

Call

import 'package:aspectd/aspectd.dart';@Aspect()
@pragma("vm:entry-point")
class CallDemo{
@Call("package:app/calculator.dart","Calculator","-getCurTime")
@pragma("vm:entry-point")
Future<String> getCurTime(PointCut pointcut) async{
print('Aspectd:KWLM02');
print('${pointcut.sourceInfos.toString()}');
Future<String> result = pointcut.proceed();
String test = await result;
print('Aspectd:KWLM03');
print('${test}');
return result;
}
}

Execute

import 'package:aspectd/aspectd.dart';@Aspect()
@pragma("vm:entry-point")
class ExecuteDemo{
@Execute("package:app/calculator.dart","Calculator","-getCurTime")
@pragma("vm:entry-point")
Future<String> getCurTime(PointCut pointcut) async{
print('Aspectd:KWLM12');
print('${pointcut.sourceInfos.toString()}');
Future<String> result = pointcut.proceed();
String test = await result;
print('Aspectd:KWLM13');
print('${test}');
return result;
}

Inject

@override
Widget build(BuildContext context) {
final Map<TapGestureRecognizer> gestures = <Type, GestureRecognizerFactory>{};
if (onTapDown ! = null || onTapUp ! = null || onTap ! = null || onTapCancel ! = null) {
gestures[TapGestureRecognizer] = GestureRecognizerFactoryWithHandlers<TapGestureRecognizer>(
() => TapGestureRecognizer(debugOwner: this),
(TapGestureRecognizer instance) {
instance
..onTapDown = onTapDown
..onTapUp = onTapUp
..onTap = onTap
..onTapCancel = onTapCancel;
},
);
}
import 'package:aspectd/aspectd.dart';@Aspect()
@pragma("vm:entry-point")
class InjectDemo{
@Inject("package:flutter/src/widgets/gesture_detector.dart","GestureDetector","-build", lineNum:452)
@pragma("vm:entry-point")
static void onTapBuild() {
Object instance; //Aspectd Ignore
Object context; //Aspectd Ignore
print(instance);
print(context);
print('Aspectd:KWLM25');
}
}

Build Process Support

kylewong@KyleWongdeMacBook-Pro fluttermaster % git apply --3way /Users/kylewong/Codes/AOP/aspectd/0001-aspectd.patch
kylewong@KyleWongdeMacBook-Pro fluttermaster % rm bin/cache/flutter_tools.stamp
kylewong@KyleWongdeMacBook-Pro fluttermaster % flutter doctor -v
Building flutter tool...

Practice and Consideration

Conclusion

Original Source

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