SF: Decouple MessageQueue

Define an ICompositor interface against which MessageQueue (which ought
to be an implementation detail of Scheduler) is implemented. Change the
equivocal invalidate/refresh nomenclature to commit/composite. Schedule
sampling only after composite.

Bug: 185535769
Test: libsurfaceflinger_unittest
Change-Id: I0c18f312459bae48531449f24f7b53c104fc5812
diff --git a/services/surfaceflinger/Scheduler/MessageQueue.cpp b/services/surfaceflinger/Scheduler/MessageQueue.cpp
index 4d51125..043a536 100644
--- a/services/surfaceflinger/Scheduler/MessageQueue.cpp
+++ b/services/surfaceflinger/Scheduler/MessageQueue.cpp
@@ -27,49 +27,55 @@
 #include "EventThread.h"
 #include "FrameTimeline.h"
 #include "MessageQueue.h"
-#include "SurfaceFlinger.h"
 
 namespace android::impl {
 
-void MessageQueue::Handler::dispatchRefresh() {
-    if ((mEventMask.fetch_or(eventMaskRefresh) & eventMaskRefresh) == 0) {
-        mQueue.mLooper->sendMessage(this, Message(MessageQueue::REFRESH));
+void MessageQueue::Handler::dispatchComposite() {
+    if ((mEventMask.fetch_or(kComposite) & kComposite) == 0) {
+        mQueue.mLooper->sendMessage(this, Message(kComposite));
     }
 }
 
-void MessageQueue::Handler::dispatchInvalidate(int64_t vsyncId, nsecs_t expectedVSyncTimestamp) {
-    if ((mEventMask.fetch_or(eventMaskInvalidate) & eventMaskInvalidate) == 0) {
+void MessageQueue::Handler::dispatchCommit(int64_t vsyncId, nsecs_t expectedVsyncTime) {
+    if ((mEventMask.fetch_or(kCommit) & kCommit) == 0) {
         mVsyncId = vsyncId;
-        mExpectedVSyncTime = expectedVSyncTimestamp;
-        mQueue.mLooper->sendMessage(this, Message(MessageQueue::INVALIDATE));
+        mExpectedVsyncTime = expectedVsyncTime;
+        mQueue.mLooper->sendMessage(this, Message(kCommit));
     }
 }
 
-bool MessageQueue::Handler::invalidatePending() {
-    constexpr auto pendingMask = eventMaskInvalidate | eventMaskRefresh;
-    return (mEventMask.load() & pendingMask) != 0;
+bool MessageQueue::Handler::isFramePending() const {
+    constexpr auto kPendingMask = kCommit | kComposite;
+    return (mEventMask.load() & kPendingMask) != 0;
 }
 
 void MessageQueue::Handler::handleMessage(const Message& message) {
+    const nsecs_t frameTime = systemTime();
     switch (message.what) {
-        case INVALIDATE:
-            mEventMask.fetch_and(~eventMaskInvalidate);
-            mQueue.mFlinger->onMessageReceived(message.what, mVsyncId, mExpectedVSyncTime);
-            break;
-        case REFRESH:
-            mEventMask.fetch_and(~eventMaskRefresh);
-            mQueue.mFlinger->onMessageReceived(message.what, mVsyncId, mExpectedVSyncTime);
+        case kCommit:
+            mEventMask.fetch_and(~kCommit);
+            if (!mQueue.mCompositor.commit(frameTime, mVsyncId, mExpectedVsyncTime)) {
+                return;
+            }
+            // Composite immediately, rather than after pending tasks through scheduleComposite.
+            [[fallthrough]];
+        case kComposite:
+            mEventMask.fetch_and(~kComposite);
+            mQueue.mCompositor.composite(frameTime);
+            mQueue.mCompositor.sample();
             break;
     }
 }
 
-// ---------------------------------------------------------------------------
+MessageQueue::MessageQueue(ICompositor& compositor)
+      : MessageQueue(compositor, sp<Handler>::make(*this)) {}
 
-void MessageQueue::init(const sp<SurfaceFlinger>& flinger) {
-    mFlinger = flinger;
-    mLooper = new Looper(true);
-    mHandler = new Handler(*this);
-}
+constexpr bool kAllowNonCallbacks = true;
+
+MessageQueue::MessageQueue(ICompositor& compositor, sp<Handler> handler)
+      : mCompositor(compositor),
+        mLooper(sp<Looper>::make(kAllowNonCallbacks)),
+        mHandler(std::move(handler)) {}
 
 // TODO(b/169865816): refactor VSyncInjections to use MessageQueue directly
 // and remove the EventThread from MessageQueue
@@ -110,11 +116,13 @@
     {
         std::lock_guard lock(mVsync.mutex);
         mVsync.lastCallbackTime = std::chrono::nanoseconds(vsyncTime);
-        mVsync.scheduled = false;
+        mVsync.scheduledFrameTime.reset();
     }
-    mHandler->dispatchInvalidate(mVsync.tokenManager->generateTokenForPredictions(
-                                         {targetWakeupTime, readyTime, vsyncTime}),
-                                 vsyncTime);
+
+    const auto vsyncId = mVsync.tokenManager->generateTokenForPredictions(
+            {targetWakeupTime, readyTime, vsyncTime});
+
+    mHandler->dispatchCommit(vsyncId, vsyncTime);
 }
 
 void MessageQueue::initVsync(scheduler::VSyncDispatch& dispatch,
@@ -135,8 +143,8 @@
     ATRACE_CALL();
     std::lock_guard lock(mVsync.mutex);
     mVsync.workDuration = workDuration;
-    if (mVsync.scheduled) {
-        mVsync.expectedWakeupTime = mVsync.registration->schedule(
+    if (mVsync.scheduledFrameTime) {
+        mVsync.scheduledFrameTime = mVsync.registration->schedule(
                 {mVsync.workDuration.get().count(),
                  /*readyDuration=*/0, mVsync.lastCallbackTime.count()});
     }
@@ -168,7 +176,7 @@
     mLooper->sendMessage(handler, Message());
 }
 
-void MessageQueue::invalidate() {
+void MessageQueue::scheduleCommit() {
     ATRACE_CALL();
 
     {
@@ -181,15 +189,14 @@
     }
 
     std::lock_guard lock(mVsync.mutex);
-    mVsync.scheduled = true;
-    mVsync.expectedWakeupTime =
+    mVsync.scheduledFrameTime =
             mVsync.registration->schedule({.workDuration = mVsync.workDuration.get().count(),
                                            .readyDuration = 0,
                                            .earliestVsync = mVsync.lastCallbackTime.count()});
 }
 
-void MessageQueue::refresh() {
-    mHandler->dispatchRefresh();
+void MessageQueue::scheduleComposite() {
+    mHandler->dispatchComposite();
 }
 
 void MessageQueue::injectorCallback() {
@@ -198,24 +205,22 @@
     while ((n = DisplayEventReceiver::getEvents(&mInjector.tube, buffer, 8)) > 0) {
         for (int i = 0; i < n; i++) {
             if (buffer[i].header.type == DisplayEventReceiver::DISPLAY_EVENT_VSYNC) {
-                mHandler->dispatchInvalidate(buffer[i].vsync.vsyncId,
-                                             buffer[i].vsync.expectedVSyncTimestamp);
+                mHandler->dispatchCommit(buffer[i].vsync.vsyncId,
+                                         buffer[i].vsync.expectedVSyncTimestamp);
                 break;
             }
         }
     }
 }
 
-std::optional<std::chrono::steady_clock::time_point> MessageQueue::nextExpectedInvalidate() {
-    if (mHandler->invalidatePending()) {
-        return std::chrono::steady_clock::now();
+auto MessageQueue::getScheduledFrameTime() const -> std::optional<Clock::time_point> {
+    if (mHandler->isFramePending()) {
+        return Clock::now();
     }
 
     std::lock_guard lock(mVsync.mutex);
-    if (mVsync.scheduled) {
-        LOG_ALWAYS_FATAL_IF(!mVsync.expectedWakeupTime.has_value(), "callback was never scheduled");
-        const auto expectedWakeupTime = std::chrono::nanoseconds(*mVsync.expectedWakeupTime);
-        return std::optional<std::chrono::steady_clock::time_point>(expectedWakeupTime);
+    if (const auto time = mVsync.scheduledFrameTime) {
+        return Clock::time_point(std::chrono::nanoseconds(*time));
     }
 
     return std::nullopt;