跟着源码学习OpenHarmony应用启动流程-Application&Ability初始化

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跟着源码学习OpenHarmony应用启动流程-Application&Ability初始化

（文章已获得诚迈科技资深研发工程师-汪语授权）

一、引言

本文基于OpenAtom OpenHarmony（以下简称“OpenHarmony”） v4.0 Release版本的源码，对应用进程初始化后MainThread初始化及调用AttachApplication、LaunchApplication、LaunchAbility的过程做了分析和总结，该流程贯穿了应用程序的用户进程和系统服务进程。

二、启动框架与核心类简介

2.1 启动框架须知
如下图所示，OpenHarmony应用冷启动过程大致分为四个阶段：应用进程创建&初始化、Application&Ability初始化、Ability/AbilityStage生命周期、加载绘制首页。

2.2 应用启动流程的核心类须知
●AppMgrService是应用管理服务主线程类，实现了IPC调用IAppMgr的接口，并通过AMSEventHandler将进程内各类事件及任务发送到主线程。
●AppRunningManager记录了应用的信息、应用的运行状态、进程信息等，内部持有了模块运行信息列表，应用第一次启动时，会先创建。
●AppSpawn是app孵化器，通过监听本地socket，接收客户端的请求消息。创建Ability应用所在进程，为Ability应用设置相应的权限，并预加载一些通用的模块。
●AbilityLoader负责注册和加载开发者Ability模块。开发者开发的Ability先调用AbilityLoader的注册接口注册到框架中，接着Ability启动时会被实例化。
●AbilityManager负责AbilityKit和Ability管理服务进行IPC的通信。
●MainThread是应用进程的核心类。应用进程内各类事件及任务通过MainThread中mainHandler投递到主线程并调用MainThread中的方法执行。
●AbilityThread是应用线程的核心类，是操作各种Ability生命周期及方法的入口。

三、源码分析

1.主线程初始化，通过IPC机制，AMS调用AttachApplication，再回调AMS端
foundation\ability\ability_runtime\frameworks\native\appkit\app\main_thread.cpp

void MainThread::Start()
{
sptr<MainThread> thread = sptr<MainThread>(new (std::nothrow) MainThread());
......
thread->Init(runner);
thread->Attach(); }
void MainThread::Init()
{
auto task = [weak]() {
auto appThread = weak.promote();
appThread->SetRunnerStarted(true);
};
if (!mainHandler_->PostTask(task)) {
HILOG_ERROR("MainThread::Init PostTask task failed");
}
watchdog_->Init(mainHandler_);
extensionConfigMgr_->Init();
}
void MainThread::Attach()
{
if (!ConnectToAppMgr()) {
return;
}
mainThreadState_ = MainThreadState::ATTACH;
}
bool MainThread::ConnectToAppMgr()
{
auto object = OHOS::DelayedSingleton<SysMrgClient>::GetInstance()->GetSystemAbility(APP_MGR_SERVICE_ID);
appMgr_ = iface_cast<IAppMgr>(object);
appMgr_->AttachApplication(this);
}

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客户端发送 attach application 请求

foundation\ability\ability_runtime\interfaces\inner_api\app_manager\src\appmgr\app_mgr_proxy.cpp

AppMgrProxy::AttachApplication(const sptr<IRemoteObject> &obj)
{
sptr<IRemoteObject> remote = Remote();
remote->SendRequest(static_cast<uint32_t>(IAppMgr::Message::APP_ATTACH_APPLICATION), ...);
}

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服务端收到 attach application 请求

foundation\ability\ability_runtime\interfaces\inner_api\app_manager\src\appmgr\app_mgr_stub.cpp

int32_t AppMgrStub::HandleAttachApplication(MessageParcel &data, MessageParcel &reply)
{
sptr<IRemoteObject> client = data.ReadRemoteObject();
AttachApplication(client);
}

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foundation\ability\ability_runtime\services\appmgr\src\app_mgr_service.cpp

void AppMgrService::AttachApplication(const sptr<IRemoteObject> &app)
{
pid_t pid = IPCSkeleton::GetCallingPid();
AddAppDeathRecipient(pid);
std::function<void()> attachApplicationFunc =
std::bind(&AppMgrServiceInner::AttachApplication, appMgrServiceInner_, pid, iface_cast<IAppScheduler>(app));
taskHandler_->SubmitTask(attachApplicationFunc, TASK_ATTACH_APPLICATION);
}

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函数处理逻辑回到服务层

foundation\ability\ability_runtime\services\appmgr\src/app_mgr_service_inner.cpp

void AppMgrServiceInner::AttachApplication(const pid_t pid, const sptr<IAppScheduler> &appScheduler)
{
......
appRecord->SetApplicationClient(appScheduler);
appRecord->RegisterAppDeathRecipient();
if (appRecord->GetState() == ApplicationState::APP_STATE_CREATE) {
LaunchApplication(appRecord);
}
eventInfo.pid = appRecord->GetPriorityObject()->GetPid();
eventInfo.processName = appRecord->GetProcessName();
AAFwk::EventReport::SendAppEvent(AAFwk::EventName::APP_ATTACH, HiSysEventType::BEHAVIOR, eventInfo);
}<div class="document"><div class="section"><p class="paragraph text-align-type-left" style="margin: 3pt 0pt; font-family: 等线; font-size: 12pt;"><span data-font-family="default" style="font-size: 11pt; letter-spacing: 0pt; vertical-align: baseline;">
</span></p></div></div>void AppMgrServiceInner::LaunchApplication(const std::shared_ptr<AppRunningRecord> &appRecord)
{
appRecord->LaunchApplication(*configuration_);
appRecord->SetState(ApplicationState::APP_STATE_READY);
appRecord->SetRestartResidentProcCount(restartResidentProcCount);
......
appRecord->LaunchPendingAbilities();
AAFwk::EventReport::SendAppEvent(AAFwk::EventName::APP_LAUNCH, HiSysEventType::BEHAVIOR, eventInfo);
}

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2.应用初始化，通过AppRunningRecord调用LaunchApplication

应用第一次启动时，会先创建AppRunningRecord

foundation\ability\ability_runtime\services\appmgr\src\app_running_record.cpp

void AppRunningRecord::LaunchApplication(const Configuration &config)
{
appLifeCycleDeal_->GetApplicationClient()
......
launchData.SetProcessInfo(processInfo);
launchData.SetRecordId(appRecordId_);
launchData.SetUId(mainUid_);
launchData.SetUserTestInfo(userTestRecord_);
launchData.SetAppIndex(appIndex_);
appLifeCycleDeal_->LaunchApplication(launchData, config);
}

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foundation\ability\ability_runtime\services\appmgr\src\app_lifecycle_deal.cpp

void AppLifeCycleDeal::LaunchAbility(const std::shared_ptr<AbilityRunningRecord> &ability)
{
appThread_->ScheduleLaunchApplication(launchData, config);
}

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处理启动应用（加载依赖库、初始化资源管理器等）等逻辑

foundation\ability\ability_runtime\frameworks\native\appkit\app\main_thread.cpp

void MainThread::ScheduleLaunchApplication(const AppLaunchData &data, const Configuration &config)
{
appThread->HandleLaunchApplication(data, config);
}
void MainThread::HandleLaunchApplication(const AppLaunchData &data, const Configuration &config)
{
if (!InitCreate(contextDeal, appInfo, processInfo)) {
return;
}
if (IsNeedLoadLibrary(bundleName)) {
ChangeToLocalPath(bundleName, appInfo.moduleSourceDirs, localPaths);
LoadAbilityLibrary(localPaths);
LoadNativeLiabrary(bundleInfo, appInfo.nativeLibraryPath);
}
if (appInfo.needAppDetail) {
LoadAppDetailAbilityLibrary(appInfo.appDetailAbilityLibraryPath);
}
LoadAppLibrary();
if (isStageBased) {
AppRecovery::GetInstance().InitApplicationInfo(GetMainHandler(), GetApplicationInfo());
}
// create contextImpl
......
if (isStageBased) {
// Create runtime
......
application_->SetRuntime(std::move(runtime));
AbilityLoader::GetInstance().RegisterAbility("Ability", [application = application_]() {
return Ability::Create(application->GetRuntime());
});
LoadAllExtensions(jsEngine);
contextDeal->initResourceManager(resourceManager);
contextDeal->SetApplicationContext(application_);
application_->AttachBaseContext(contextDeal);
application_->SetAbilityRecordMgr(abilityRecordMgr_);
application_->SetConfiguration(config);
contextImpl->SetConfiguration(application_->GetConfiguration());
applicationImpl_->SetRecordId(appLaunchData.GetRecordId());
applicationImpl_->SetApplication(application_);
mainThreadState_ = MainThreadState::READY;
......
applicationImpl_->PerformAppReady()
nwebMgr->PreStartNWebSpawnProcess();
......
// init resourceManager.
......
}

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3. 通过RunningRecord调用LaunchPendingAbilities,最终创建Ability

foundation\ability\ability_runtime\services\appmgr\src/module_running_record.cpp

void ModuleRunningRecord::LaunchPendingAbilities()
{
for (const auto &item : abilities_) {
const auto &ability = item.second;
if (ability->GetState() == AbilityState::ABILITY_STATE_CREATE && ability->GetToken() &&
appLifeCycleDeal_->GetApplicationClient()) {
appLifeCycleDeal_->LaunchAbility(ability);
ability->SetState(AbilityState::ABILITY_STATE_READY);
}
}
}
void ModuleRunningRecord::LaunchAbility(const std::shared_ptr<AbilityRunningRecord> &ability)
{
appLifeCycleDeal_->LaunchAbility(ability);
ability->SetState(AbilityState::ABILITY_STATE_READY);
}

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通过IPC调用ScheduleLaunchAbility函数

foundation\ability\ability_runtime\services\appmgr\src/app_lifecycle_deal.cpp

AppLifeCycleDeal::LaunchAbility(const std::shared_ptr<AbilityRunningRecord> &ability)
{
if (appThread_ && ability) {
appThread_->ScheduleLaunchAbility(*(ability->GetAbilityInfo()), ability->GetToken(),
ability->GetWant());
}
}

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foundation\ability\ability_runtime\frameworks\native\appkit\app\main_thread.cpp

MainThread::ScheduleLaunchAbility(const AbilityInfo &info, const sptr<IRemoteObject> &token, const std::shared_ptr<AAFwk::Want> &want)
{
auto task = [weak, abilityRecord]() {
...
auto appThread = weak.promote();
appThread->HandleLaunchAbility(abilityRecord);
};
mainHandler_->PostTask(task);
}
MainThread::HandleLaunchAbility(const std::shared_ptr<AbilityLocalRecord> &abilityRecord)
{
abilityRecordMgr_->SetToken(abilityToken);
abilityRecordMgr_->AddAbilityRecord(abilityToken, abilityRecord);
//创建AbilityStage
std::shared_ptr<AbilityRuntime::Context> stageContext = application_->AddAbilityStage(abilityRecord);
//启动Ability线程
AbilityThread::AbilityThreadMain(application_, abilityRecord, stageContext);
}

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foundation\ability\ability_runtime\frameworks\native\appkit\app\ohos_application.cpp

bool OHOSApplication::AddAbilityStage(const AppExecFwk::HapModuleInfo &hapModuleInfo)
{
......
auto stageContext = std::make_shared<AbilityRuntime::ContextImpl>();
stageContext->SetParentContext(abilityRuntimeContext_);
stageContext->InitHapModuleInfo(hapModuleInfo);
stageContext->SetConfiguration(GetConfiguration());
auto abilityStage = AbilityRuntime::AbilityStage::Create(runtime_, *moduleInfo);
abilityStage->Init(stageContext);
Want want;
abilityStage->OnCreate(want);
abilityStages_[hapModuleInfo.moduleName] = abilityStage;
return true;
}

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foundation\ability\ability_runtime\frameworks\native\appkit\ability_runtime\app\ability_stage.cpp

std::shared_ptr<AbilityStage> AbilityStage::Create(
const std::unique_ptr<Runtime>& runtime, const AppExecFwk::HapModuleInfo& hapModuleInfo)
{
......
switch (runtime->GetLanguage()) {
case Runtime::Language::JS:
return JsAbilityStage::Create(runtime, hapModuleInfo);
default:
return std::make_shared<AbilityStage>();
}
}
void AbilityStage::AddAbility(const sptr<IRemoteObject> &token,
const std::shared_ptr<AppExecFwk::AbilityLocalRecord> &abilityRecord)
{
......
abilityRecords_[token] = abilityRecord;
}

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foundation\ability\ability_runtime\frameworks\native\appkit\ability_runtime\app\ability_stage.cpp

td::shared_ptr<AbilityStage> JsAbilityStage::Create(){
auto& jsRuntime = static_cast<JsRuntime&>(*runtime);
std::string srcPath(hapModuleInfo.name);
std::string moduleName(hapModuleInfo.moduleName);
moduleName.append("::").append("AbilityStage");
......
//srcPath.append("/assets/js/");
//srcPath.append("AbilityStage.abc");
srcPath.append(hapModuleInfo.srcPath);
srcPath.append("/AbilityStage.abc");
auto moduleObj = jsRuntime.LoadModule(moduleName, srcPath, hapModuleInfo.hapPath,
hapModuleInfo.compileMode == AppExecFwk::CompileMode::ES_MODULE, commonChunkFlag);
return std::make_shared<JsAbilityStage>(jsRuntime, std::move(moduleObj));
}
void JsAbilityStage::Init(const std::shared_ptr<Context> &context)
{
AbilityStage::Init(context);
}
void JsAbilityStage::OnCreate(const AAFwk::Want &want) const
{
AbilityStage::OnCreate(want);
......
auto& nativeEngine = jsRuntime_.GetNativeEngine();
NativeValue* value = jsAbilityStageObj_->Get();
nativeEngine.CallFunction(value, methodOnCreate, nullptr, 0);
}
//AbilityStage
void AbilityStage::Init(const std::shared_ptr<Context>& context){
context_ = context;
}
void AbilityStage::OnCreate(const AAFwk::Want &want) cons{
HILOG_DEBUG("AbilityStage OnCreate come.");
}

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foundation\ability\ability_runtime\frameworks\native\ability\native\ability_thread.cpp

至此，关于应用启动过程中application和ability初始化梳理清楚，OpenHarmony的源码关键Api和源码路径也都列举了出来，有疑问可自行获取源码加深理解。

四、总结-时序图
本文基于以上源码分析进行了总结，绘制了时序图，如下图所示。

五、参考链接
OpenHarmony 4.0 Release官方文档：
https://gitee.com/openharmony/do ... lease.mdOpenHarmony 应用模型介绍：https://gitee.com/openharmony/do ... lity-launch-type.md
OpenHarmony IPC / RPC通信开发指导：
https://gitee.com/openharmony/communication_ipc
OpenHarmony源码仓获取地址：
https://www.openharmony.cn/download
Ability启动过程：
https://ost.51cto.com/posts/22188

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