Second Patch for async RenderEngine

- pass a vector of <LayerSettings> instead of a vector of pointers to
drawLayers function to ensure lifecycle safety.
- capture all local variables to call drawLayerInternals in the render
engine thread to avoid of pointers being invalidated if it takes long
time to pop mFunctions calls.
- change renderScreenImplLocked return type as a shared_future
object to unblock SF main thread for screen capture events.
- block region sampling thread only when SF main thread hasn't
completed capture screen event.

Bug: 180657548
Test: SurfaceFlinger_test, android.hardware.graphics.composer@2.2-vts, libcompositionengine_test, librenderengine_test, libsurfaceflinger_unittest pass
Change-Id: I615f2927d30524988fb12df22fe331e7217c3058

1 files changed, 32 insertions, 0 deletions

diff --git a/services/surfaceflinger/TransactionCallbackInvoker.cpp b/services/surfaceflinger/TransactionCallbackInvoker.cpp
index c1eb8966d1..8fbf0b4d07 100644
--- a/services/surfaceflinger/TransactionCallbackInvoker.cpp
+++ b/services/surfaceflinger/TransactionCallbackInvoker.cpp
@@ -154,6 +154,38 @@ status_t TransactionCallbackInvoker::addCallbackHandle(const sp<CallbackHandle>&
     // destroyed the client side is dead and there won't be anyone to send the callback to.
     sp<IBinder> surfaceControl = handle->surfaceControl.promote();
     if (surfaceControl) {
+        sp<Fence> prevFence = nullptr;
+
+        for (const auto& futureStruct : handle->previousReleaseFences) {
+            sp<Fence> currentFence = sp<Fence>::make(dup(futureStruct.get().drawFence));
+            if (prevFence == nullptr && currentFence->getStatus() != Fence::Status::Invalid) {
+                prevFence = currentFence;
+                handle->previousReleaseFence = prevFence;
+            } else if (prevFence != nullptr) {
+                // If both fences are signaled or both are unsignaled, we need to merge
+                // them to get an accurate timestamp.
+                if (prevFence->getStatus() != Fence::Status::Invalid &&
+                    prevFence->getStatus() == currentFence->getStatus()) {
+                    char fenceName[32] = {};
+                    snprintf(fenceName, 32, "%.28s", handle->name.c_str());
+                    sp<Fence> mergedFence = Fence::merge(fenceName, prevFence, currentFence);
+                    if (mergedFence->isValid()) {
+                        handle->previousReleaseFence = mergedFence;
+                        prevFence = handle->previousReleaseFence;
+                    }
+                } else if (currentFence->getStatus() == Fence::Status::Unsignaled) {
+                    // If one fence has signaled and the other hasn't, the unsignaled
+                    // fence will approximately correspond with the correct timestamp.
+                    // There's a small race if both fences signal at about the same time
+                    // and their statuses are retrieved with unfortunate timing. However,
+                    // by this point, they will have both signaled and only the timestamp
+                    // will be slightly off; any dependencies after this point will
+                    // already have been met.
+                    handle->previousReleaseFence = currentFence;
+                }
+            }
+        }
+        handle->previousReleaseFences = {};
         FrameEventHistoryStats eventStats(handle->frameNumber,
                                           handle->gpuCompositionDoneFence->getSnapshot().fence,
                                           handle->compositorTiming, handle->refreshStartTime,