RIL层
RIL 首先这个是用来和CP（基带处理器）通信。可以把他看成是硬件层的抽象，这里的硬件当然是各式各样的模块，比如wcdma, gsm, evdo等等。这样ril上层即telephony就无需关心当前是何种模块，比如我要拨出一个电话，我只要下发一个请求号为RIL_REQUEST_DIAL的请求即可，无需关心发送什么AT命令，这是软件思想中隔离变化的体现。
【硬件抽象层，控制mode端,RIL则是将虚拟电话系统的标准功能转换成实际的所使用的Modem的AT指令 telephony 与ril层通过unix domain socket通信
/framework/base/telephony/java/com/android/internal/telephony/RIL.java】
RILD
是RIL(Radio Interface Layer) Deamon的简称。通过过socket将请求发送给RILD的消息循环，消息循环则将请求转发给底层通信模块（直接调用底层的库）来实现对通信模块功能的调用。反之，当通信模块有类似于来电的消息时，也会通过RILD的回调，将信息包装成消息，发送到RILD的消息循环中去处理，最后通过socket送给telephony
短信接收
从/framework/base/telephony/java/com/android/internal/telephony/RIL.java看起。
发送短信和接收短信是通过Receiver和Sender架构。这里讲Receiver。
class RILReceiver implements Runnable{
......
public void
run() {
.......
try {
for (;;) {
LocalSocket s = null;
LocalSocketAddress l;
.......
........
try {
s = new LocalSocket();
l = new LocalSocketAddress(socketRil,
LocalSocketAddress.Namespace.RESERVED);
s.connect(l);
.......
InputStream is = mSocket.getInputStream();
for (;;) {
Parcel p;
length = readRilMessage(is, buffer);
if (length < 0) {
// End-of-stream reached
break;
}
p = Parcel.obtain();
p.unmarshall(buffer, 0, length);
p.setDataPosition(0);
//Log.v(LOG_TAG, "Read packet: " + length + " bytes");
processResponse(p);
p.recycle();
..........
}
通过socket获取数据后，最后交给了processResponse(p);
private void processResponse (Parcel p) {
int type;
type = p.readInt();
if (type == RESPONSE_UNSOLICITED) {
processUnsolicited (p);
} else if (type == RESPONSE_SOLICITED) {
processSolicited (p);
}
releaseWakeLockIfDone();
}
这里有2种type.一种是主动上报，比如网络状态，短信，来电等都不需要经过请求，用unsolicited词语专门描述。RESPONSE_SOLICITED是必须先请求然后才响应的类型。当然这里是短信接收肯定会走前者。processUnsolicited该方法会根据当前的请求的类型，如果是短信则是RIL_UNSOL_RESPONSE_NEW_SMS，以下是其调用的代码；
case RIL_UNSOL_RESPONSE_NEW_SMS: {
if (RILJ_LOGD) unsljLog(response);
// FIXME this should move up a layer
String a[] = new String[2];
a[1] = (String)ret;
SmsMessage sms;
sms = SmsMessage.newFromCMT(a);
if (mSMSRegistrant != null) {
mSMSRegistrant
.notifyRegistrant(new AsyncResult(null, sms, null));
}
break;
}
因为 RIL extends BaseCommands 。其中mSMSRegistrant为BaseCommands 中的对象。 追踪.notifyRegistrant(new AsyncResult(null, sms, null));会发现
void
internalNotifyRegistrant (Object result, Throwable exception)
{
Handler h = getHandler();
if (h == null) {
clear();
} else {
Message msg = Message.obtain();
msg.what = what;
msg.obj = new AsyncResult(userObj, result, exception);
h.sendMessage(msg);
}
}
发送了一条mesage对象。而哪里接收这条消息并处理呢？ 在BaseCommands 中查看mSMSRegistrant的实例化会发现。
public void setOnNewSMS(Handler h, int what, Object obj) {。。。}
其中的handler h 就是接收message并处理的handler.追踪setOnNewSMS会发现最后是在
mCm.setOnNewSMS(this, EVENT_NEW_SMS, null);
framework/base/telephony/java/com/android/internal/telephony/SMSDispatcher.java中实现。
SMSDispatcher就是继承handler.所以处理函数为
@Override
public void handleMessage(Message msg) {
....
switch (msg.what) {
case EVENT_NEW_SMS:
....
SmsMessage sms;
ar = (AsyncResult) msg.obj;
......
sms = (SmsMessage) ar.result;
try {
int result = dispatchMessag(sms.mWrappedSmsMessage);
........
}
}
追踪dispatchMessag实现，会在GsmSMSDispatch和CdmaSMSDispatch中实现。这里只看GsmSMDispatch.经过dispatchNormalMessage，经一系列的判断处理最后普通短信将交给dispatchPdus(pdus);这个方法处理.
protected void dispatchPdus(byte[][] pdus) {
Intent intent = new Intent(Intents.SMS_RECEIVED_ACTION);
intent.putExtra("pdus", pdus);
dispatch(intent, "android.permission.RECEIVE_SMS");
}
void dispatch(Intent intent, String permission) {
mWakeLock.acquire(WAKE_LOCK_TIMEOUT);
mContext.sendOrderedBroadcast(intent, permission, mResultReceiver,
this, Activity.RESULT_OK, null, null);
}
【注：在dispatchPdus方法内，就可以处理防火墙相关事件。让他不发出接收到短信的广播】
然后短信app中PrivilegedSmsReceiver广播接收器接收到广播后会调用onReceiveWithPrivilege方法.此时进入APP层。
packages/apps/Mms/src/com/android/mms/transaction/PrivilegedSmsReceiver
intent.setClass(context, SmsReceiverService.class);
intent.putExtra("result", getResultCode());
beginStartingService(context, intent);
启动SmsReceiverService。跟踪源码可以看到如下代码
private final class ServiceHandler extends Handler {
public ServiceHandler(Looper looper) {
super(looper);
}
......
if (MESSAGE_SENT_ACTION.equals(intent.getAction())) {
handleSmsSent(intent, error);
} else if (SMS_RECEIVED_ACTION.equals(action)) {
handleSmsReceived(intent, error);
} else if (ACTION_BOOT_COMPLETED.equals(action)) {
handleBootCompleted();
} else if (TelephonyIntents.ACTION_SERVICE_STATE_CHANGED.equals(action)) {
handleServiceStateChanged(intent);
} else if (ACTION_SEND_MESSAGE.endsWith(action)) {
handleSendMessage(intent);
}
}
接收短信会走 handleSmsReceived(intent, error); 函数
private void handleSmsReceived(Intent intent, int error){
......
Uri messageUri = insertMessage(this, intent, error, format);
......
if (messageUri != null) {
MessagingNotification.blockingUpdateNewMessageIndicator(this, true, false);
} else {
SmsMessage sms = msgs[0];
SmsMessage msg = SmsMessage.createFromPdu(sms.getPdu());
CharSequence messageChars = msg.getMessageBody();
String message = messageChars.toString();
if (!TextUtils.isEmpty(message)) {
MessagingNotification.notifyClassZeroMessage(this, msgs[0]
.getOriginatingAddress());
}
......
}
这里做了2个操作。 insertMessage 插入数据库。插入成功后提示用户blockingUpdateNewMessageIndicator。插入失败也通知用户notifyClassZeroMessage