From fc46c1e6e58ff5acdc72feea409e4aa03f978be9 Mon Sep 17 00:00:00 2001
From: Vishnu Nair <vishnun@google.com>
Date: Wed, 21 Apr 2021 08:31:32 -0700
Subject: Introduce ASurfaceTransaction_setOnCommit api

Introduce a new callback for SurfaceControl transactions that
fire after we commit a transaction in SurfaceFlinger. This
will help some clients pace when they should apply the next
transaction so it get applied on the next vsync. If they wait for
the existing transaction complete callback, there may not be
enough time between when the client applies the transaction
and surface flinger waking up and apply it on the new vsync.
This would mean the update would arrive a frame late.

This callback is guaranteed to fire before the transaction complete
callback. It includes all the stats as the transaction complete
callback with the exception of jank data, present fence
and the previous buffer release fence.

This callback piggybacks of the oncomplete callback implementation
by modifying the callback id to provide a callback type. The
callbacks are filtered in SurfaceFlinger to invoke them earlier. In
SurfaceComposerClient, they are filtered again to make sure the
callbacks are invoked in order, oncommit before oncomplete.

Bug: 185843251
Test: atest ASurfaceControlTest
Change-Id: I57e85d75214376935e366d3825a6f3f1a8a4e79b
---
 services/surfaceflinger/SurfaceFlinger.cpp | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

(limited to 'services/surfaceflinger/SurfaceFlinger.cpp')

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 5f5987f8a3..8e2d5e5253 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2029,6 +2029,9 @@ bool SurfaceFlinger::handleMessageInvalidate() {
     ATRACE_CALL();
     bool refreshNeeded = handlePageFlip();
 
+    // Send on commit callbacks
+    mTransactionCallbackInvoker.sendCallbacks();
+
     if (mVisibleRegionsDirty) {
         computeLayerBounds();
     }
@@ -3789,14 +3792,30 @@ bool SurfaceFlinger::callingThreadHasUnscopedSurfaceFlingerAccess(bool usePermis
 uint32_t SurfaceFlinger::setClientStateLocked(
         const FrameTimelineInfo& frameTimelineInfo, const ComposerState& composerState,
         int64_t desiredPresentTime, bool isAutoTimestamp, int64_t postTime, uint32_t permissions,
-        std::unordered_set<ListenerCallbacks, ListenerCallbacksHash>& listenerCallbacks) {
+        std::unordered_set<ListenerCallbacks, ListenerCallbacksHash>& outListenerCallbacks) {
     const layer_state_t& s = composerState.state;
     const bool privileged = permissions & Permission::ACCESS_SURFACE_FLINGER;
+
+    std::vector<ListenerCallbacks> filteredListeners;
     for (auto& listener : s.listeners) {
+        // Starts a registration but separates the callback ids according to callback type. This
+        // allows the callback invoker to send on latch callbacks earlier.
         // note that startRegistration will not re-register if the listener has
         // already be registered for a prior surface control
-        mTransactionCallbackInvoker.startRegistration(listener);
-        listenerCallbacks.insert(listener);
+
+        ListenerCallbacks onCommitCallbacks = listener.filter(CallbackId::Type::ON_COMMIT);
+        if (!onCommitCallbacks.callbackIds.empty()) {
+            mTransactionCallbackInvoker.startRegistration(onCommitCallbacks);
+            filteredListeners.push_back(onCommitCallbacks);
+            outListenerCallbacks.insert(onCommitCallbacks);
+        }
+
+        ListenerCallbacks onCompleteCallbacks = listener.filter(CallbackId::Type::ON_COMPLETE);
+        if (!onCompleteCallbacks.callbackIds.empty()) {
+            mTransactionCallbackInvoker.startRegistration(onCompleteCallbacks);
+            filteredListeners.push_back(onCompleteCallbacks);
+            outListenerCallbacks.insert(onCompleteCallbacks);
+        }
     }
 
     sp<Layer> layer = nullptr;
@@ -4049,8 +4068,8 @@ uint32_t SurfaceFlinger::setClientStateLocked(
         }
     }
     std::vector<sp<CallbackHandle>> callbackHandles;
-    if ((what & layer_state_t::eHasListenerCallbacksChanged) && (!s.listeners.empty())) {
-        for (auto& [listener, callbackIds] : s.listeners) {
+    if ((what & layer_state_t::eHasListenerCallbacksChanged) && (!filteredListeners.empty())) {
+        for (auto& [listener, callbackIds] : filteredListeners) {
             callbackHandles.emplace_back(new CallbackHandle(listener, callbackIds, s.surface));
         }
     }
-- 
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