ARouter源码解析（四）
arouter-compiler version : 1.2.2
前言
之前对 arouter-api 做了整个流程的分析，今天来看看 arouter-compiler 。
arouter-compiler 主要是利用 apt 在编译期自动生成代码的。之前我们看到的 ARouter$$Root$$app 、 ARouter$$Group$$test 和 Test1Activity$$ARouter$$Autowired 等都是 arouter-compiler 生成的。
那接下来就分析分析 arouter-compiler 是怎么生成这些源码的。
arouter-compiler
arouter-compiler 中 processor 有三种：
- AutowiredProcessor : 用来生成像
Test1Activity$$ARouter$$Autowired这种类型； - InterceptorProcessor : 用来生成像
ARouter$$Interceptors$$app这种类型； - RouteProcessor : 用来生成像
ARouter$$Root$$app，ARouter$$Providers$$app和ARouter$$Group$$test这种类型；
RouteProcessor
在这里我们就只分析 RouteProcessor 了。
RouteProcessor 相比其他两个 Processor 来说，代码更长，逻辑更加复杂。并且 RouteProcessor 主要处理的是路由映射这一块。其他两个 RouteProcessor 也是大同小异，有兴趣的同学可以自行阅读源码。
先来看看 RouteProcessor 的定义：
@AutoService(Processor.class)
@SupportedOptions({KEY_MODULE_NAME, KEY_GENERATE_DOC_NAME})
@SupportedSourceVersion(SourceVersion.RELEASE_7)
@SupportedAnnotationTypes({ANNOTATION_TYPE_ROUTE, ANNOTATION_TYPE_AUTOWIRED})
public class RouteProcessor extends AbstractProcessor {
...
}RouteProcessor 类上面的注解很多，我们一个一个来看：
- @AutoService 会自动在 META-INF 文件夹下生成 Processor 配置信息文件，避免手动配置的麻烦;
- @SupportedOptions 指定 Processor 支持的选项参数名称，KEY_MODULE_NAME 就是 AROUTER_MODULE_NAME ，KEY_GENERATE_DOC_NAME 就是 AROUTER_GENERATE_DOC；没错，这两个就是我们一开始在 build.gradle 中配置的。
- @SupportedSourceVersion 指定 Processor 支持的 JDK 的版本；
- @SupportedAnnotationTypes 指定 Processor 处理的注解；
接着，趁热打铁。来瞧瞧 RouteProcessor 的 init 方法。
@Override
public synchronized void init(ProcessingEnvironment processingEnv) {
super.init(processingEnv);
mFiler = processingEnv.getFiler(); // Generate class.
types = processingEnv.getTypeUtils(); // Get type utils.
elements = processingEnv.getElementUtils(); // Get class meta.
typeUtils = new TypeUtils(types, elements);
logger = new Logger(processingEnv.getMessager()); // Package the log utils.
// Attempt to get user configuration [moduleName]
Map<String, String> options = processingEnv.getOptions();
if (MapUtils.isNotEmpty(options)) {
moduleName = options.get(KEY_MODULE_NAME);
generateDoc = VALUE_ENABLE.equals(options.get(KEY_GENERATE_DOC_NAME));
}
if (StringUtils.isNotEmpty(moduleName)) {
moduleName = moduleName.replaceAll("[^0-9a-zA-Z_]+", "");
logger.info("The user has configuration the module name, it was [" + moduleName + "]");
} else {
logger.error(NO_MODULE_NAME_TIPS);
throw new RuntimeException("ARouter::Compiler >>> No module name, for more information, look at gradle log.");
}
// 如果需要生成路由 doc
if (generateDoc) {
try {
docWriter = mFiler.createResource(
StandardLocation.SOURCE_OUTPUT,
PACKAGE_OF_GENERATE_DOCS,
"arouter-map-of-" + moduleName + ".json"
).openWriter();
} catch (IOException e) {
logger.error("Create doc writer failed, because " + e.getMessage());
}
}
iProvider = elements.getTypeElement(Consts.IPROVIDER).asType();
logger.info(">>> RouteProcessor init. <<<");
}在 init 方法中，主要获取了 KEY_MODULE_NAME 和 KEY_GENERATE_DOC_NAME 这两个编译选项参数。然后判断一下是否需要生成路由文档。
在 init 方法中获取参数后，接着就是 process 方法。
process 方法就好像是 main 方法一样，在这里面都是 processer 处理注解自动生成代码的逻辑。
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
if (CollectionUtils.isNotEmpty(annotations)) {
// 获取 @Route 注解的集合
Set<? extends Element> routeElements = roundEnv.getElementsAnnotatedWith(Route.class);
try {
logger.info(">>> Found routes, start... <<<");
this.parseRoutes(routeElements);
} catch (Exception e) {
logger.error(e);
}
return true;
}
return false;
}在 process 中调用了 parseRoutes ，parseRoutes 方法实在是太长了，在这里我们进行分段讲解吧。
private void parseRoutes(Set<? extends Element> routeElements) throws IOException {
if (CollectionUtils.isNotEmpty(routeElements)) {
// prepare the type an so on.
logger.info(">>> Found routes, size is " + routeElements.size() + " <<<");
rootMap.clear();
// Activity 类型
TypeMirror type_Activity = elements.getTypeElement(ACTIVITY).asType();
// Service 类型
TypeMirror type_Service = elements.getTypeElement(SERVICE).asType();
// Fragment 类型
TypeMirror fragmentTm = elements.getTypeElement(FRAGMENT).asType();
// v4 Fragment 类型
TypeMirror fragmentTmV4 = elements.getTypeElement(Consts.FRAGMENT_V4).asType();
// IRouteGroup 类型
TypeElement type_IRouteGroup = elements.getTypeElement(IROUTE_GROUP);
// IProviderGroup 类型
TypeElement type_IProviderGroup = elements.getTypeElement(IPROVIDER_GROUP);
// 获取 RouteMeta 和 RouteType 的类名
ClassName routeMetaCn = ClassName.get(RouteMeta.class);
ClassName routeTypeCn = ClassName.get(RouteType.class);
/*
构造 ARouter$$Root$$xxx 的 loadInto 方法入参类型
Build input type, format as :
Map<String, Class<? extends IRouteGroup>>
*/
ParameterizedTypeName inputMapTypeOfRoot = ParameterizedTypeName.get(
ClassName.get(Map.class),
ClassName.get(String.class),
ParameterizedTypeName.get(
ClassName.get(Class.class),
WildcardTypeName.subtypeOf(ClassName.get(type_IRouteGroup))
)
);
/*
构造 ARouter$$Group$$xxx 的 loadInto 方法入参类型
Map<String, RouteMeta>
*/
ParameterizedTypeName inputMapTypeOfGroup = ParameterizedTypeName.get(
ClassName.get(Map.class),
ClassName.get(String.class),
ClassName.get(RouteMeta.class)
);
/*
构造方法入参参数名称
Build input param name.
*/
ParameterSpec rootParamSpec = ParameterSpec.builder(inputMapTypeOfRoot, "routes").build();
ParameterSpec groupParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "atlas").build();
ParameterSpec providerParamSpec = ParameterSpec.builder(inputMapTypeOfGroup, "providers").build(); // Ps. its param type same as groupParamSpec!
/*
构造 ARouter$$Root$$xxx 的 loadInto 方法
Build method : 'loadInto'
*/
MethodSpec.Builder loadIntoMethodOfRootBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
.addAnnotation(Override.class)
.addModifiers(PUBLIC)
.addParameter(rootParamSpec);
...
}
}parseRoutes 方法一开始，做足了准备。下面就到了放大招的时候了。
// Follow a sequence, find out metas of group first, generate java file, then statistics them as root.
for (Element element : routeElements) {
TypeMirror tm = element.asType();
Route route = element.getAnnotation(Route.class);
RouteMeta routeMeta;
// 如果 element 修饰的类是 Activity 类型的
if (types.isSubtype(tm, type_Activity)) { // Activity
logger.info(">>> Found activity route: " + tm.toString() + " <<<");
// 获取 Activity 中 @Autowired 注解的属性，IProvider 类型的除外
Map<String, Integer> paramsType = new HashMap<>();
Map<String, Autowired> injectConfig = new HashMap<>();
for (Element field : element.getEnclosedElements()) {
if (field.getKind().isField() && field.getAnnotation(Autowired.class) != null && !types.isSubtype(field.asType(), iProvider)) {
// It must be field, then it has annotation, but it not be provider.
Autowired paramConfig = field.getAnnotation(Autowired.class);
String injectName = StringUtils.isEmpty(paramConfig.name()) ? field.getSimpleName().toString() : paramConfig.name();
paramsType.put(injectName, typeUtils.typeExchange(field));
injectConfig.put(injectName, paramConfig);
}
}
// 构造 activity 类型的路由数据
routeMeta = new RouteMeta(route, element, RouteType.ACTIVITY, paramsType);
routeMeta.setInjectConfig(injectConfig);
} else if (types.isSubtype(tm, iProvider)) { // IProvider 类型
logger.info(">>> Found provider route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.PROVIDER, null);
} else if (types.isSubtype(tm, type_Service)) { // Service 类型
logger.info(">>> Found service route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.parse(SERVICE), null);
} else if (types.isSubtype(tm, fragmentTm) || types.isSubtype(tm, fragmentTmV4)) { // fragment 类型
logger.info(">>> Found fragment route: " + tm.toString() + " <<<");
routeMeta = new RouteMeta(route, element, RouteType.parse(FRAGMENT), null);
} else {
throw new RuntimeException("ARouter::Compiler >>> Found unsupported class type, type = [" + types.toString() + "].");
}
// 将生成好的 routeMeta 按组存放进入 groupMap 中
categories(routeMeta);
}上面这段代码主要将每个 routeElement 进行了分类，将 @Route 修饰的类信息封装进 RouteMeta 中。再把 RouteMeta 按照组名分好组存进 groupMap 中。
// 构造 ARouter$$Providers$$xxx 的 loadInto 方法
MethodSpec.Builder loadIntoMethodOfProviderBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
.addAnnotation(Override.class)
.addModifiers(PUBLIC)
.addParameter(providerParamSpec);
Map<String, List<RouteDoc>> docSource = new HashMap<>();
// Start generate java source, structure is divided into upper and lower levels, used for demand initialization.
for (Map.Entry<String, Set<RouteMeta>> entry : groupMap.entrySet()) {
// 每组的组名
String groupName = entry.getKey();
// 构造 ARouter$$Group$$xxx 的 loadInto 方法
MethodSpec.Builder loadIntoMethodOfGroupBuilder = MethodSpec.methodBuilder(METHOD_LOAD_INTO)
.addAnnotation(Override.class)
.addModifiers(PUBLIC)
.addParameter(groupParamSpec);
List<RouteDoc> routeDocList = new ArrayList<>();
// Build group method body
Set<RouteMeta> groupData = entry.getValue();
for (RouteMeta routeMeta : groupData) {
RouteDoc routeDoc = extractDocInfo(routeMeta);
// 类名。比如 com.alibaba.android.arouter.demo.testservice.HelloService
ClassName className = ClassName.get((TypeElement) routeMeta.getRawType());
switch (routeMeta.getType()) {
case PROVIDER: // Need cache provider's super class
// 获取该节点下的接口
List<? extends TypeMirror> interfaces = ((TypeElement) routeMeta.getRawType()).getInterfaces();
// 遍历接口
for (TypeMirror tm : interfaces) {
routeDoc.addPrototype(tm.toString());
// 如果接口是 iProvider 类型
if (types.isSameType(tm, iProvider)) { // Its implements iProvider interface himself.
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
(routeMeta.getRawType()).toString(),
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath(),
routeMeta.getGroup());
} else if (types.isSubtype(tm, iProvider)) { // 如果是 iProvider 的子接口
// This interface extend the IProvider, so it can be used for mark provider
loadIntoMethodOfProviderBuilder.addStatement(
"providers.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, null, " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
tm.toString(), // So stupid, will duplicate only save class name.
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath(),
routeMeta.getGroup());
}
}
break;
default:
break;
}上面的代码最终会生成 ARouter
Providers
xxx 的 loadInto 方法，比如像这样：
providers.put("com.alibaba.android.arouter.demo.testservice.HelloService", RouteMeta.build(RouteType.PROVIDER, HelloServiceImpl.class, "/yourservicegroupname/hello", "yourservicegroupname", null, -1, -2147483648));那我们接着看。
// 构造 RouteMeta 的 paramType 参数
StringBuilder mapBodyBuilder = new StringBuilder();
Map<String, Integer> paramsType = routeMeta.getParamsType();
Map<String, Autowired> injectConfigs = routeMeta.getInjectConfig();
if (MapUtils.isNotEmpty(paramsType)) {
List<RouteDoc.Param> paramList = new ArrayList<>();
for (Map.Entry<String, Integer> types : paramsType.entrySet()) {
mapBodyBuilder.append("put(\"").append(types.getKey()).append("\", ").append(types.getValue()).append("); ");
RouteDoc.Param param = new RouteDoc.Param();
Autowired injectConfig = injectConfigs.get(types.getKey());
param.setKey(types.getKey());
param.setType(TypeKind.values()[types.getValue()].name().toLowerCase());
param.setDescription(injectConfig.desc());
param.setRequired(injectConfig.required());
paramList.add(param);
}
routeDoc.setParams(paramList);
}
String mapBody = mapBodyBuilder.toString();
// 以下代码生成这种模版 atlas.put("/test/activity1", RouteMeta.build(RouteType.ACTIVITY, Test1Activity.class, "/test/activity1", "test", new java.util.HashMap<String, Integer>(){{put("ser", 9); }}, -1, -2147483648));
loadIntoMethodOfGroupBuilder.addStatement(
"atlas.put($S, $T.build($T." + routeMeta.getType() + ", $T.class, $S, $S, " + (StringUtils.isEmpty(mapBody) ? null : ("new java.util.HashMap<String, Integer>(){{" + mapBodyBuilder.toString() + "}}")) + ", " + routeMeta.getPriority() + ", " + routeMeta.getExtra() + "))",
routeMeta.getPath(),
routeMetaCn,
routeTypeCn,
className,
routeMeta.getPath().toLowerCase(),
routeMeta.getGroup().toLowerCase());
routeDoc.setClassName(className.toString());
routeDocList.add(routeDoc);
}
// 生成 ARouter$$Group$$xxx 类
String groupFileName = NAME_OF_GROUP + groupName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
TypeSpec.classBuilder(groupFileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(type_IRouteGroup))
.addModifiers(PUBLIC)
.addMethod(loadIntoMethodOfGroupBuilder.build())
.build()
).build().writeTo(mFiler);
logger.info(">>> Generated group: " + groupName + "<<<");
rootMap.put(groupName, groupFileName);
docSource.put(groupName, routeDocList);上面代码主要做的事情就是遍历 groupmap 集合给 ARouter
Group
xxx 类中的 loadInto 添加方法体，并生成 java 文件。
if (MapUtils.isNotEmpty(rootMap)) {
// Generate root meta by group name, it must be generated before root, then I can find out the class of group.
// 生成 ARouter$$Root$$app 的 loadInto 方法体
for (Map.Entry<String, String> entry : rootMap.entrySet()) {
loadIntoMethodOfRootBuilder.addStatement("routes.put($S, $T.class)", entry.getKey(), ClassName.get(PACKAGE_OF_GENERATE_FILE, entry.getValue()));
}
}
// Output route doc
if (generateDoc) {
docWriter.append(JSON.toJSONString(docSource, SerializerFeature.PrettyFormat));
docWriter.flush();
docWriter.close();
}
// 生成 ARouter$$Providers$$app 类
String providerMapFileName = NAME_OF_PROVIDER + SEPARATOR + moduleName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
TypeSpec.classBuilder(providerMapFileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(type_IProviderGroup))
.addModifiers(PUBLIC)
.addMethod(loadIntoMethodOfProviderBuilder.build())
.build()
).build().writeTo(mFiler);
logger.info(">>> Generated provider map, name is " + providerMapFileName + " <<<");
// 生成 ARouter$$Root$$app 类
String rootFileName = NAME_OF_ROOT + SEPARATOR + moduleName;
JavaFile.builder(PACKAGE_OF_GENERATE_FILE,
TypeSpec.classBuilder(rootFileName)
.addJavadoc(WARNING_TIPS)
.addSuperinterface(ClassName.get(elements.getTypeElement(ITROUTE_ROOT)))
.addModifiers(PUBLIC)
.addMethod(loadIntoMethodOfRootBuilder.build())
.build()
).build().writeTo(mFiler);
logger.info(">>> Generated root, name is " + rootFileName + " <<<");以上，就是整个 RouteProcessor 的流程。看完 RouteProcessor 之后，相信你对 ARouter 的的了解也更加深入了。
之后，也会对 ARouter 的 arouter-register 模块做一个深入解析，敬请期待吧。
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原始发表：2019.01.06 ，如有侵权请联系 cloudcommunity@tencent.com 删除
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