bool EventThread::threadLoop() {
DisplayEventReceiver::Event event;
Vector< sp<EventThread::Connection> > signalConnections;
signalConnections = waitForEvent(&event);
// dispatch events to listeners...
const size_t count = signalConnections.size();
for (size_t i=0 ; i<count ; i++) {
const sp<Connection>& conn(signalConnections[i]);
// now see if we still need to report this event
status_t err = conn->postEvent(event);
if (err == -EAGAIN || err == -EWOULDBLOCK) {
// The destination doesn't accept events anymore, it's probably
// full. For now, we just drop the events on the floor.
// FIXME: Note that some events cannot be dropped and would have
// to be re-sent later.
// Right-now we don't have the ability to do this.
ALOGW("EventThread: dropping event (%08x) for connection %p",
event.header.type, conn.get());
} else if (err < 0) {
// handle any other error on the pipe as fatal. the only
// reasonable thing to do is to clean-up this connection.
// The most common error we'll get here is -EPIPE.
removeDisplayEventConnection(signalConnections[i]);
}
}
return true;
}
bool EventThread::threadLoop() {
DisplayEventReceiver::Event event;
Vector< sp<EventThread::Connection> > signalConnections; // 比如会有多个组件或者应用注册这个Connection
signalConnections = waitForEvent(&event); // 获取到一个Evente(vsync/hotplug)
// dispatch events to listeners...
const size_t count = signalConnections.size(); // 有多少路Layer/Display连接过来？
// 如果每路都是对不同的Event感兴趣怎么办？
for (size_t i = 0 ; i < count ; i++) {
const sp<Connection>& conn(signalConnections[i]);
// now see if we still need to report this event
status_t err = conn->postEvent(event); // 通过BitTube把收到的Event散播出去，每次就一个Event，如果有多个display和不同的event
// 岂不很繁忙？
if (err == -EAGAIN || err == -EWOULDBLOCK) {
// The destination doesn't accept events anymore, it's probably
// full. For now, we just drop the events on the floor.
// FIXME: Note that some events cannot be dropped and would have
// to be re-sent later.
// Right-now we don't have the ability to do this.
ALOGW("EventThread: dropping event (%08x) for connection %p",
event.header.type, conn.get());
} else if (err < 0) {
// handle any other error on the pipe as fatal. the only
// reasonable thing to do is to clean-up this connection.
// The most common error we'll get here is -EPIPE.
removeDisplayEventConnection(signalConnections[i]);
}
}
// Derived class must implement threadLoop(). The thread starts its life
// here. There are two ways of using the Thread object:
// 1) loop: if threadLoop() returns true, it will be called again if
// requestExit() wasn't called.
// 2) once: if threadLoop() returns false, the thread will exit upon return.
// virtual bool threadLoop() = 0;
return true;
}
