Android 7.1.1短信接收流程解析-优快云博客

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Platform:Android-7.1.1_r22

FW中短信接收流程

注：本文基于Android_7.1.1原生代码。

当有新短信时，RIL会收到RIL_UNSOL_RESPONSE_NEW_SMS消息。
private void processUnsolicited (Parcel p, int type) {
......
case RIL_UNSOL_RESPONSE_NEW_SMS: {
......
// 通知RIL_UNSOL_RESPONSE_NEW_SMS事件的监听者
if (mGsmSmsRegistrant != null) {
mGsmSmsRegistrant
.notifyRegistrant(new AsyncResult(null, sms, null));
}
break;
}
......
}

GsmInboundSmsHandler中会注册监听RIL_UNSOL_RESPONSE_NEW_SMS事件。
private GsmInboundSmsHandler(Context context, SmsStorageMonitor storageMonitor,
Phone phone) {
......
phone.mCi.setOnNewGsmSms(getHandler(), EVENT_NEW_SMS, null);
......
}

BaseCommands.java
public void setOnNewGsmSms(Handler h, int what, Object obj) {
mGsmSmsRegistrant = new Registrant (h, what, obj);
}

GsmInboundSmsHandler收到RIL的通知后，在其父类InboundSmsHandler中进行处理。
InboundSmsHandler是一个状态机，此类的作用是将收到的短信存储后再通过广播发出去，
并发送相应给短信中心，发送广播后，就会删除短信内容。如果向短信中心发送相应后，
还未发送广播时，程序就crash了，在程序再次启动后会重新发送广播。

TODO:补充状态机流程

private class IdleState extends State {
......
public boolean processMessage(Message msg) {
log("IdleState.processMessage:" + msg.what);
if (DBG) log("Idle state processing message type " + msg.what);
switch (msg.what) {
case EVENT_NEW_SMS:
case EVENT_INJECT_SMS:
case EVENT_BROADCAST_SMS:
// 这里并没有对消息进行处理，而是把消息推迟，到Delivering状态再进行处理
deferMessage(msg);
transitionTo(mDeliveringState);
return HANDLED;
......
}
}

在退出IdleState时会获取mWakeLock锁。
public void exit() {
mWakeLock.acquire();
if (DBG) log("acquired wakelock, leaving Idle state");
}

接下来在DeliveringState中处理EVENT_NEW_SMS事件。

private class DeliveringState extends State {
......
public boolean processMessage(Message msg) {
log("DeliveringState.processMessage:" + msg.what);
switch (msg.what) {
case EVENT_NEW_SMS:
// handle new SMS from RIL
handleNewSms((AsyncResult) msg.obj);
sendMessage(EVENT_RETURN_TO_IDLE);
return HANDLED;
......
}
}

private void handleNewSms(AsyncResult ar) {
......
try {
SmsMessage sms = (SmsMessage) ar.result;
result = dispatchMessage(sms.mWrappedSmsMessage);
} catch (RuntimeException ex) {
......
}

// RESULT_OK means that the SMS will be acknowledged by special handling,
// e.g. for SMS-PP data download. Any other result, we should ack here.
if (result != Activity.RESULT_OK) {
boolean handled = (result == Intents.RESULT_SMS_HANDLED);
notifyAndAcknowledgeLastIncomingSms(handled, result, null);
}
}