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03 · 读写信号全链路时序图

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03 · 读写信号全链路时序图

源码：SettingsCarPropertyManager.kt + VehicleControlManager.java + CarPropertyCacheManager.java

1. 读信号全链路（以 getIntProperty 为例）

sequenceDiagram
    autonumber
    participant Ctrl as 业务Controller
    participant SCPM as SettingsCarPropertyManager
    participant Cache as mPropertiesCache
    participant VCM as VehicleControlManager
    participant CPCM as CarPropertyCacheManager
    participant AOSP as AOSP CarPropertyManager
    participant Car as 车端

    Ctrl->>SCPM: getIntProperty(propId, areaId, default)<br/>[:331]
    SCPM->>SCPM: getProperty Int(propId, areaId)<br/>[:371]
    SCPM->>Cache: getCachedProp(propId, areaId)<br/>key = propId#areaId [:580]

    alt 缓存命中
        Cache-->>SCPM: CarPropertyValue
        SCPM-->>Ctrl: .value ?: default
    else 缓存未命中
        SCPM->>SCPM: remoteGetProperty(propId, areaId) [:391]
        SCPM->>SCPM: 检查 isConnected() [:392]
        alt 未连接
            SCPM-->>Ctrl: null (返回 default)
        else 已连接
            SCPM->>VCM: getProperty(propId, areaId) [:395]
            VCM->>CPCM: 取值(命中缓存直接返回)
            CPCM->>AOSP: getProperty(propId, areaId)
            AOSP->>Car: 读取信号
            Car-->>AOSP: CarPropertyValue
            AOSP-->>VCM: CarPropertyValue
            VCM-->>SCPM: CarPropertyValue

            SCPM->>Cache: cachePropVal(value) [:397]
            Note over Cache: 首次缓存可注入<br/>getPropValueForFirstCache 终态值

            SCPM->>SCPM: propId 是否在 observedSet? [:398]
            opt 不在观察集合(隐式注册)
                SCPM->>VCM: registerPropertyCallback(dispatcher, propId) [:400]
                VCM->>CPCM: registerPropertyCallback(cb, propId)
                CPCM->>AOSP: registerCallback(internalCb, propId)
                SCPM->>SCPM: mNoNeedObservedPropertyIdSet.add(propId) [:402]
            end
            SCPM-->>Ctrl: .value ?: default
        end
    end

要点

  • 缓存优先：getProperty 先查 mPropertiesCache（key=propId#areaId），命中直接返回，不走 binder。
  • 不缓存读：getPropertyWithoutCache 强制走 remoteGetProperty，绕过缓存（适合需要实时值的场景，如 CarConfigManager）。
  • 隐式注册：remoteGetProperty 拿到值后，若 propId 不在 mObservedPropertyIdSet，会自动注册底层回调并记到 mNoNeedObservedPropertyIdSet——意思是”你 get 过一次，后续变化就会被通知”。这会随 release() / unregisterPropertyCallback 一起清理。

2. 写信号全链路（以 setCarPropertyBySync 为例）

sequenceDiagram
    autonumber
    participant Ctrl as 业务Controller
    participant SCPM as SettingsCarPropertyManager
    participant VCM as VehicleControlManager
    participant AOSP as AOSP CarPropertyManager
    participant Car as 车端
    participant Handler as mTimeoutHandler
    participant Cb as SettingsCarPropertyEventCallback
    participant Cache as mPropertiesCache

    Ctrl->>SCPM: setCarPropertyBySync(propId, value, areaId) [:408]
    SCPM->>SCPM: setCarProperty(propId, val, areaId, isSync=true) [:413/423]
    SCPM->>SCPM: reportOneTrackWhenSetProperty(...) 埋点 [:429]
    SCPM->>SCPM: 检查 isConnected() [:430]
    alt 未连接
        SCPM->>SCPM: 打 w 日志后 return [:431]
    else 已连接
        SCPM->>SCPM: mNoNeedObservedPropertyIdSet.add(propId) [:435]
        SCPM->>SCPM: 按 propVal 类型分发 [:438-474]
        alt Int
            SCPM->>VCM: setIntPropertyBySync(propId, val, areaId) [:440]
        else Float
            SCPM->>VCM: setFloatPropertyBySync(propId, val, areaId) [:445]
        else Int 数组
            SCPM->>VCM: setIntArrayPropertyBySync(...) [:452]
        else List (BATCH_PROP 批量)
            SCPM->>VCM: setBatchPropertyBySync(list) [:466]
        else 其他类型
            SCPM->>SCPM: typeSupport=false, 打 e 日志 [:478]
        end
        VCM->>AOSP: setProperty(...) (异步线程 ThreadPoolUtils.ASYNC)
        AOSP->>Car: 下发控制指令

        SCPM->>SCPM: startTimeOutMonitor(propId, val, areaId) [:476]
        opt BATCH_PROP
            SCPM->>SCPM: 遍历集合逐个 startTimeOutMonitorReal [:531-535]
        end
        SCPM->>SCPM: startTimeOutMonitorReal [:541]
        Note over SCPM: 取 timeoutPropId / timeoutValue<br/>仅对 observedSet 内的 propId 计时<br/>TIMEOUT_IGNORE 跳过 [:546-553]
        SCPM->>Handler: sendMessageDelayed(msgId, timeout) [:557]
        Note over Handler: msgId = (propId#areaId).hashCode()

        Car-->>AOSP: 车端回弹
        AOSP-->>Cb: onChangeEvent(value)
        Cb->>Cb: mockError? / mockTimeout? 拦截 [:664-672]
        Cb->>Cache: cachePropVal(value) [:673]
        Cb->>Cb: processTimeout(value, getTimeoutFlag) [:674]
        alt CONTINUE
            Note over Cb: 继续等待，不动计时
        else RESTART
            Cb->>Handler: 重启计时 [:167-177]
        else REMOVE(默认)
            Cb->>Handler: removeMessages(msgId) [:181-186]
        end
        Cb->>Cb: propId 是否在 observedSet? [:675]
        alt 在观察集合
            Cb-->>Ctrl: onPropertyChanged(value) [:680]
        else 不在
            Note over Cb: 打 w 日志，不上抛 [:682]
        end
    end

超时触发分支（回弹没在窗口内到达）

sequenceDiagram
    Handler->>Handler: 延时到期 handleMessage [:150]
    Handler->>Handler: handlePropertyTimeout(propId, areaId, propVal) [:191]
    Handler-->>Ctrl: mCallback.onSetPropertyTimeout(propId, areaId) [:194]
    Handler->>Cache: 取下发时缓存值 vs 当前缓存值 [:196]
    alt 下发值 != 缓存值
        Handler-->>Ctrl: mCallback.onDataVerifyFailed(propId, areaId, propVal) [:199]
        Note over Handler: 数据校验失败:车端最终态与下发不一致
    end

3. setCarProperty vs setCarPropertyWithoutDelayCheck

两者代码高度相似，关键差异：

特性setCarProperty (423)setCarPropertyWithoutDelayCheck (482)
超时监控✅ 调 startTimeOutMonitor (476)❌ 不调，无超时检测
类型校验✅ typeSupport 校验，不支持打 e 日志 (475)❌ 无校验，静默跳过不支持的类型
埋点✅✅
连接检查✅✅
自动注册 observedSet✅✅
类型分发Int/Float/Array/ListInt/Float/Array/List

选用建议：

  • 大多数控制信号用 setCarProperty / setCarPropertyBySync——需要回弹确认，超时能提示用户”操作未生效”。
  • 只读状态查询、或不需要确认的指令用 setCarPropertyWithoutDelayCheck。

4. 关键文件位置

文件路径
SettingsCarPropertyManagerbase/settingsVehicleLib/.../vehicle/SettingsCarPropertyManager.kt
VehicleControlManagerbase/settingsVehicleLib/.../vehicle/VehicleControlManager.java
CarPropertyCacheManagerbase/settingsVehicleLib/.../vehicle/CarPropertyCacheManager.java
NewBaseCarServiceManagerbase/settingsVehicleLib/.../vehicle/NewBaseCarServiceManager.java
LocalCarManagerbase/settingsVehicleLib/.../vehicle/LocalCarManager.java
CarPropertyManagerCallbackbase/settingsVehicleLib/.../vehicle/CarPropertyManagerCallback.java

下一篇：04-超时监控与回调机制.md

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