rewrite SF's message loop on top of Looper

Change-Id: Ib56139f87a5c0b124e34da5c8151207219b2577b
diff --git a/services/surfaceflinger/MessageQueue.cpp b/services/surfaceflinger/MessageQueue.cpp
index aebe1b8..1846ccb 100644
--- a/services/surfaceflinger/MessageQueue.cpp
+++ b/services/surfaceflinger/MessageQueue.cpp
@@ -29,169 +29,81 @@
 
 // ---------------------------------------------------------------------------
 
-void MessageList::insert(const sp<MessageBase>& node) 
-{
-    LIST::iterator cur(mList.begin());
-    LIST::iterator end(mList.end());
-    while (cur != end) {
-        if (*node < **cur) {
-            mList.insert(cur, node);
-            return;
-        }
-        ++cur;
-    }
-    mList.insert(++end, node);
+MessageBase::MessageBase()
+    : MessageHandler() {
 }
 
-void MessageList::remove(MessageList::LIST::iterator pos) 
-{
-    mList.erase(pos);
+MessageBase::~MessageBase() {
 }
 
+void MessageBase::handleMessage(const Message&) {
+    this->handler();
+    barrier.open();
+};
+
 // ---------------------------------------------------------------------------
 
 MessageQueue::MessageQueue()
-    : mInvalidate(false)
-{
-    mInvalidateMessage = new MessageBase(INVALIDATE);
-}
-
-MessageQueue::~MessageQueue()
+    : mLooper(new Looper(true)),
+      mInvalidatePending(0)
 {
 }
 
-sp<MessageBase> MessageQueue::waitMessage(nsecs_t timeout)
-{
-    sp<MessageBase> result;
+MessageQueue::~MessageQueue() {
+}
 
-    bool again;
+void MessageQueue::waitMessage() {
     do {
-        const nsecs_t timeoutTime = systemTime() + timeout;
-        while (true) {
-            Mutex::Autolock _l(mLock);
-            nsecs_t now = systemTime();
-            nsecs_t nextEventTime = -1;
-
-            LIST::iterator cur(mMessages.begin());
-            if (cur != mMessages.end()) {
-                result = *cur;
-            }
-            
-            if (result != 0) {
-                if (result->when <= now) {
-                    // there is a message to deliver
-                    mMessages.remove(cur);
-                    break;
-                }
-                nextEventTime = result->when;
-                result = 0;
-            }
-
-            // see if we have an invalidate message
-            if (mInvalidate) {
-                mInvalidate = false;
-                mInvalidateMessage->when = now;
-                result = mInvalidateMessage;
-                break;
-            }
-
-            if (timeout >= 0) {
-                if (timeoutTime < now) {
-                    // we timed-out, return a NULL message
-                    result = 0;
-                    break;
-                }
-                if (nextEventTime > 0) {
-                    if (nextEventTime > timeoutTime) {
-                        nextEventTime = timeoutTime;
-                    }
-                } else {
-                    nextEventTime = timeoutTime;
-                }
-            }
-
-            if (nextEventTime >= 0) {
-                //LOGD("nextEventTime = %lld ms", nextEventTime);
-                if (nextEventTime > 0) {
-                    // we're about to wait, flush the binder command buffer
-                    IPCThreadState::self()->flushCommands();
-                    const nsecs_t reltime = nextEventTime - systemTime();
-                    if (reltime > 0) {
-                        mCondition.waitRelative(mLock, reltime);
-                    }
-                }
-            } else {
-                //LOGD("going to wait");
-                // we're about to wait, flush the binder command buffer
-                IPCThreadState::self()->flushCommands();
-                mCondition.wait(mLock);
-            }
-        } 
-        // here we're not holding the lock anymore
-
-        if (result == 0)
+        // handle invalidate events first
+        if (android_atomic_and(0, &mInvalidatePending) != 0)
             break;
 
-        again = result->handler();
-        if (again) {
-            // the message has been processed. release our reference to it
-            // without holding the lock.
-            result->notify();
-            result = 0;
-        }
-        
-    } while (again);
+        IPCThreadState::self()->flushCommands();
 
-    return result;
+        int32_t ret = mLooper->pollOnce(-1);
+        switch (ret) {
+            case ALOOPER_POLL_WAKE:
+                // we got woken-up there is work to do in the main loop
+                continue;
+
+            case ALOOPER_POLL_CALLBACK:
+                // callback was handled, loop again
+                continue;
+
+            case ALOOPER_POLL_TIMEOUT:
+                // timeout (should not happen)
+                continue;
+
+            case ALOOPER_POLL_ERROR:
+                LOGE("ALOOPER_POLL_ERROR");
+                continue;
+
+            default:
+                // should not happen
+                LOGE("Looper::pollOnce() returned unknown status %d", ret);
+                continue;
+        }
+    } while (true);
 }
 
 status_t MessageQueue::postMessage(
-        const sp<MessageBase>& message, nsecs_t relTime, uint32_t flags)
+        const sp<MessageBase>& messageHandler, nsecs_t relTime)
 {
-    return queueMessage(message, relTime, flags);
+    const Message dummyMessage;
+    if (relTime > 0) {
+        mLooper->sendMessageDelayed(relTime, messageHandler, dummyMessage);
+    } else {
+        mLooper->sendMessage(messageHandler, dummyMessage);
+    }
+    return NO_ERROR;
 }
 
 status_t MessageQueue::invalidate() {
-    Mutex::Autolock _l(mLock);
-    mInvalidate = true;
-    mCondition.signal();
+    android_atomic_or(1, &mInvalidatePending);
+    mLooper->wake();
     return NO_ERROR;
 }
 
-status_t MessageQueue::queueMessage(
-        const sp<MessageBase>& message, nsecs_t relTime, uint32_t flags)
-{
-    Mutex::Autolock _l(mLock);
-    message->when = systemTime() + relTime;
-    mMessages.insert(message);
-    
-    //LOGD("MessageQueue::queueMessage time = %lld ms", message->when);
-    //dumpLocked(message);
-
-    mCondition.signal();
-    return NO_ERROR;
-}
-
-void MessageQueue::dump(const sp<MessageBase>& message)
-{
-    Mutex::Autolock _l(mLock);
-    dumpLocked(message);
-}
-
-void MessageQueue::dumpLocked(const sp<MessageBase>& message)
-{
-    LIST::const_iterator cur(mMessages.begin());
-    LIST::const_iterator end(mMessages.end());
-    int c = 0;
-    while (cur != end) {
-        const char tick = (*cur == message) ? '>' : ' ';
-        LOGD("%c %d: msg{.what=%08x, when=%lld}",
-                tick, c, (*cur)->what, (*cur)->when);
-        ++cur;
-        c++;
-    }
-}
-
 // ---------------------------------------------------------------------------
 
 }; // namespace android
diff --git a/services/surfaceflinger/MessageQueue.h b/services/surfaceflinger/MessageQueue.h
index 890f809..25030a6 100644
--- a/services/surfaceflinger/MessageQueue.h
+++ b/services/surfaceflinger/MessageQueue.h
@@ -23,7 +23,7 @@
 
 #include <utils/threads.h>
 #include <utils/Timers.h>
-#include <utils/List.h>
+#include <utils/Looper.h>
 
 #include "Barrier.h"
 
@@ -31,92 +31,39 @@
 
 // ---------------------------------------------------------------------------
 
-class MessageBase;
-
-class MessageList 
-{
-    List< sp<MessageBase> > mList;
-    typedef List< sp<MessageBase> > LIST;
-public:
-    inline LIST::iterator begin()                { return mList.begin(); }
-    inline LIST::const_iterator begin() const    { return mList.begin(); }
-    inline LIST::iterator end()                  { return mList.end(); }
-    inline LIST::const_iterator end() const      { return mList.end(); }
-    inline bool isEmpty() const { return mList.empty(); }
-    void insert(const sp<MessageBase>& node);
-    void remove(LIST::iterator pos);
-};
-
-// ============================================================================
-
-class MessageBase : 
-    public LightRefBase<MessageBase>
+class MessageBase : public MessageHandler
 {
 public:
-    nsecs_t     when;
-    uint32_t    what;
-    int32_t     arg0;    
-
-    MessageBase() : when(0), what(0), arg0(0) { }
-    MessageBase(uint32_t what, int32_t arg0=0)
-        : when(0), what(what), arg0(arg0) { }
+    MessageBase();
     
     // return true if message has a handler
-    virtual bool handler() { return false; }
+    virtual bool handler() = 0;
 
     // waits for the handler to be processed
     void wait() const { barrier.wait(); }
-    
-    // releases all waiters. this is done automatically if
-    // handler returns true
-    void notify() const { barrier.open(); }
 
 protected:
-    virtual ~MessageBase() { }
+    virtual ~MessageBase();
 
 private:
-    mutable Barrier barrier;
-    friend class LightRefBase<MessageBase>;
-};
+    virtual void handleMessage(const Message& message);
 
-inline bool operator < (const MessageBase& lhs, const MessageBase& rhs) {
-    return lhs.when < rhs.when;
-}
+    mutable Barrier barrier;
+};
 
 // ---------------------------------------------------------------------------
 
-class MessageQueue
-{
-    typedef List< sp<MessageBase> > LIST;
-public:
+class MessageQueue {
+    sp<Looper> mLooper;
+    volatile int32_t mInvalidatePending;
 
+public:
     MessageQueue();
     ~MessageQueue();
 
-    // pre-defined messages
-    enum {
-        INVALIDATE = '_upd'
-    };
-
-    sp<MessageBase> waitMessage(nsecs_t timeout = -1);
-    
-    status_t postMessage(const sp<MessageBase>& message,
-            nsecs_t reltime=0, uint32_t flags = 0);
-
+    void waitMessage();
+    status_t postMessage(const sp<MessageBase>& message, nsecs_t reltime=0);
     status_t invalidate();
-    
-    void dump(const sp<MessageBase>& message);
-
-private:
-    status_t queueMessage(const sp<MessageBase>& message,
-            nsecs_t reltime, uint32_t flags);
-    void dumpLocked(const sp<MessageBase>& message);
-    
-    Mutex           mLock;
-    Condition       mCondition;
-    MessageList     mMessages;
-    bool            mInvalidate;
-    sp<MessageBase> mInvalidateMessage;
 };
 
 // ---------------------------------------------------------------------------
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 1b00e93..39f0f40 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -311,19 +311,8 @@
 #pragma mark Events Handler
 #endif
 
-void SurfaceFlinger::waitForEvent()
-{
-    while (true) {
-        nsecs_t timeout = -1;
-        sp<MessageBase> msg = mEventQueue.waitMessage(timeout);
-        if (msg != 0) {
-            switch (msg->what) {
-                case MessageQueue::INVALIDATE:
-                    // invalidate message, just return to the main loop
-                    return;
-            }
-        }
-    }
+void SurfaceFlinger::waitForEvent() {
+    mEventQueue.waitMessage();
 }
 
 void SurfaceFlinger::signalEvent() {