Merge "SF: Carve out LayerHandle"
diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index b65f1b4..e76b191 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -156,6 +156,7 @@
         "Effects/Daltonizer.cpp",
         "EventLog/EventLog.cpp",
         "FrontEnd/LayerCreationArgs.cpp",
+        "FrontEnd/LayerHandle.cpp",
         "FrontEnd/TransactionHandler.cpp",
         "FlagManager.cpp",
         "FpsReporter.cpp",
diff --git a/services/surfaceflinger/FrontEnd/LayerHandle.cpp b/services/surfaceflinger/FrontEnd/LayerHandle.cpp
new file mode 100644
index 0000000..75e4e3a
--- /dev/null
+++ b/services/surfaceflinger/FrontEnd/LayerHandle.cpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "LayerHandle.h"
+#include <cstdint>
+#include "Layer.h"
+#include "LayerCreationArgs.h"
+#include "SurfaceFlinger.h"
+
+namespace android::surfaceflinger {
+
+LayerHandle::LayerHandle(const sp<android::SurfaceFlinger>& flinger,
+                         const sp<android::Layer>& layer)
+      : mFlinger(flinger), mLayer(layer), mLayerId(static_cast<uint32_t>(layer->getSequence())) {}
+
+LayerHandle::~LayerHandle() {
+    if (mFlinger) {
+        mFlinger->onHandleDestroyed(this, mLayer, mLayerId);
+    }
+}
+
+const String16 LayerHandle::kDescriptor = String16("android.Layer.LayerHandle");
+
+sp<LayerHandle> LayerHandle::fromIBinder(const sp<IBinder>& binder) {
+    if (binder == nullptr) {
+        return nullptr;
+    }
+
+    BBinder* b = binder->localBinder();
+    if (b == nullptr || b->getInterfaceDescriptor() != LayerHandle::kDescriptor) {
+        ALOGD("handle does not have a valid descriptor");
+        return nullptr;
+    }
+
+    // We can safely cast this binder since its local and we verified its interface descriptor.
+    return sp<LayerHandle>::cast(binder);
+}
+
+sp<android::Layer> LayerHandle::getLayer(const sp<IBinder>& binder) {
+    sp<LayerHandle> handle = LayerHandle::fromIBinder(binder);
+    return handle ? handle->mLayer : nullptr;
+}
+
+uint32_t LayerHandle::getLayerId(const sp<IBinder>& binder) {
+    sp<LayerHandle> handle = LayerHandle::fromIBinder(binder);
+    return handle ? handle->mLayerId : UNASSIGNED_LAYER_ID;
+}
+
+} // namespace android::surfaceflinger
diff --git a/services/surfaceflinger/FrontEnd/LayerHandle.h b/services/surfaceflinger/FrontEnd/LayerHandle.h
new file mode 100644
index 0000000..5d0f783
--- /dev/null
+++ b/services/surfaceflinger/FrontEnd/LayerHandle.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <binder/Binder.h>
+#include <utils/StrongPointer.h>
+
+namespace android {
+class SurfaceFlinger;
+class Layer;
+} // namespace android
+
+namespace android::surfaceflinger {
+
+/*
+ * The layer handle is just a BBinder object passed to the client
+ * (remote process) -- we don't keep any reference on our side such that
+ * the dtor is called when the remote side let go of its reference.
+ *
+ * ~LayerHandle ensures that mFlinger->onLayerDestroyed() is called for
+ * this layer when the handle is destroyed.
+ */
+class LayerHandle : public BBinder {
+public:
+    LayerHandle(const sp<android::SurfaceFlinger>& flinger, const sp<android::Layer>& layer);
+    // for testing
+    LayerHandle(uint32_t layerId) : mFlinger(nullptr), mLayer(nullptr), mLayerId(layerId) {}
+    ~LayerHandle();
+
+    // Static functions to access the layer and layer id safely from an incoming binder.
+    static sp<LayerHandle> fromIBinder(const sp<IBinder>& handle);
+    static sp<android::Layer> getLayer(const sp<IBinder>& handle);
+    static uint32_t getLayerId(const sp<IBinder>& handle);
+    static const String16 kDescriptor;
+
+    const String16& getInterfaceDescriptor() const override { return kDescriptor; }
+
+private:
+    sp<android::SurfaceFlinger> mFlinger;
+    sp<android::Layer> mLayer;
+    const uint32_t mLayerId;
+};
+
+} // namespace android::surfaceflinger
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index b47188f..9777092 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -70,6 +70,7 @@
 #include "FrameTimeline.h"
 #include "FrameTracer/FrameTracer.h"
 #include "FrontEnd/LayerCreationArgs.h"
+#include "FrontEnd/LayerHandle.h"
 #include "LayerProtoHelper.h"
 #include "SurfaceFlinger.h"
 #include "TimeStats/TimeStats.h"
@@ -332,7 +333,7 @@
         return nullptr;
     }
     mGetHandleCalled = true;
-    return sp<Handle>::make(mFlinger, sp<Layer>::fromExisting(this));
+    return sp<LayerHandle>::make(mFlinger, sp<Layer>::fromExisting(this));
 }
 
 // ---------------------------------------------------------------------------
@@ -774,7 +775,7 @@
 }
 
 bool Layer::setRelativeLayer(const sp<IBinder>& relativeToHandle, int32_t relativeZ) {
-    sp<Layer> relative = fromHandle(relativeToHandle).promote();
+    sp<Layer> relative = LayerHandle::getLayer(relativeToHandle);
     if (relative == nullptr) {
         return false;
     }
@@ -1545,7 +1546,7 @@
 bool Layer::reparent(const sp<IBinder>& newParentHandle) {
     sp<Layer> newParent;
     if (newParentHandle != nullptr) {
-        newParent = fromHandle(newParentHandle).promote();
+        newParent = LayerHandle::getLayer(newParentHandle);
         if (newParent == nullptr) {
             ALOGE("Unable to promote Layer handle");
             return false;
@@ -1938,7 +1939,8 @@
 
 void Layer::setInputInfo(const WindowInfo& info) {
     mDrawingState.inputInfo = info;
-    mDrawingState.touchableRegionCrop = fromHandle(info.touchableRegionCropHandle.promote());
+    mDrawingState.touchableRegionCrop =
+            LayerHandle::getLayer(info.touchableRegionCropHandle.promote());
     mDrawingState.modified = true;
     mFlinger->mUpdateInputInfo = true;
     setTransactionFlags(eTransactionNeeded);
@@ -2585,23 +2587,6 @@
     mFlinger->mNumClones++;
 }
 
-const String16 Layer::Handle::kDescriptor = String16("android.Layer.Handle");
-
-wp<Layer> Layer::fromHandle(const sp<IBinder>& handleBinder) {
-    if (handleBinder == nullptr) {
-        return nullptr;
-    }
-
-    BBinder* b = handleBinder->localBinder();
-    if (b == nullptr || b->getInterfaceDescriptor() != Handle::kDescriptor) {
-        return nullptr;
-    }
-
-    // We can safely cast this binder since its local and we verified its interface descriptor.
-    sp<Handle> handle = sp<Handle>::cast(handleBinder);
-    return handle->owner;
-}
-
 bool Layer::setDropInputMode(gui::DropInputMode mode) {
     if (mDrawingState.dropInputMode == mode) {
         return false;
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 336b4ff..a3c4e59 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -226,46 +226,6 @@
         bool dimmingEnabled = true;
     };
 
-    /*
-     * Trivial class, used to ensure that mFlinger->onLayerDestroyed(mLayer)
-     * is called.
-     */
-    class LayerCleaner {
-        sp<SurfaceFlinger> mFlinger;
-        sp<Layer> mLayer;
-        BBinder* mHandle;
-
-    protected:
-        ~LayerCleaner() {
-            // destroy client resources
-            mFlinger->onHandleDestroyed(mHandle, mLayer);
-        }
-
-    public:
-        LayerCleaner(const sp<SurfaceFlinger>& flinger, const sp<Layer>& layer, BBinder* handle)
-              : mFlinger(flinger), mLayer(layer), mHandle(handle) {}
-    };
-
-    /*
-     * The layer handle is just a BBinder object passed to the client
-     * (remote process) -- we don't keep any reference on our side such that
-     * the dtor is called when the remote side let go of its reference.
-     *
-     * LayerCleaner ensures that mFlinger->onLayerDestroyed() is called for
-     * this layer when the handle is destroyed.
-     */
-    class Handle : public BBinder, public LayerCleaner {
-    public:
-        Handle(const sp<SurfaceFlinger>& flinger, const sp<Layer>& layer)
-              : LayerCleaner(flinger, layer, this), owner(layer) {}
-        const String16& getInterfaceDescriptor() const override { return kDescriptor; }
-
-        static const String16 kDescriptor;
-        wp<Layer> owner;
-    };
-
-    static wp<Layer> fromHandle(const sp<IBinder>& handle);
-
     explicit Layer(const LayerCreationArgs& args);
     virtual ~Layer();
 
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index c1eda17..cfebec7 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -124,6 +124,7 @@
 #include "FrameTimeline/FrameTimeline.h"
 #include "FrameTracer/FrameTracer.h"
 #include "FrontEnd/LayerCreationArgs.h"
+#include "FrontEnd/LayerHandle.h"
 #include "HdrLayerInfoReporter.h"
 #include "Layer.h"
 #include "LayerProtoHelper.h"
@@ -1577,7 +1578,10 @@
         return BAD_VALUE;
     }
 
-    const wp<Layer> stopLayer = fromHandle(stopLayerHandle);
+    // LayerHandle::getLayer promotes the layer object in a binder thread but we will not destroy
+    // the layer here since the caller has a strong ref to the layer's handle.
+    // TODO (b/238781169): replace layer with layer id
+    const wp<Layer> stopLayer = LayerHandle::getLayer(stopLayerHandle);
     mRegionSamplingThread->addListener(samplingArea, stopLayer, listener);
     return NO_ERROR;
 }
@@ -3698,7 +3702,7 @@
     using TransactionReadiness = TransactionHandler::TransactionReadiness;
     auto ready = TransactionReadiness::Ready;
     flushState.transaction->traverseStatesWithBuffersWhileTrue([&](const layer_state_t& s) -> bool {
-        sp<Layer> layer = Layer::fromHandle(s.surface).promote();
+        sp<Layer> layer = LayerHandle::getLayer(s.surface);
         const auto& transaction = *flushState.transaction;
         // check for barrier frames
         if (s.bufferData->hasBarrier &&
@@ -3966,7 +3970,7 @@
                 setClientStateLocked(frameTimelineInfo, state, desiredPresentTime, isAutoTimestamp,
                                      postTime, permissions, transactionId);
         if ((flags & eAnimation) && state.state.surface) {
-            if (const auto layer = fromHandle(state.state.surface).promote()) {
+            if (const auto layer = LayerHandle::getLayer(state.state.surface)) {
                 using LayerUpdateType = scheduler::LayerHistory::LayerUpdateType;
                 mScheduler->recordLayerHistory(layer.get(),
                                                isAutoTimestamp ? 0 : desiredPresentTime,
@@ -4107,7 +4111,7 @@
     uint32_t flags = 0;
     sp<Layer> layer = nullptr;
     if (s.surface) {
-        layer = fromHandle(s.surface).promote();
+        layer = LayerHandle::getLayer(s.surface);
     } else {
         // The client may provide us a null handle. Treat it as if the layer was removed.
         ALOGW("Attempt to set client state with a null layer handle");
@@ -4414,7 +4418,7 @@
     LayerCreationArgs mirrorArgs(args);
     {
         Mutex::Autolock _l(mStateLock);
-        mirrorFrom = fromHandle(mirrorFromHandle).promote();
+        mirrorFrom = LayerHandle::getLayer(mirrorFromHandle);
         if (!mirrorFrom) {
             return NAME_NOT_FOUND;
         }
@@ -4520,19 +4524,15 @@
     }
 
     args.addToRoot = args.addToRoot && callingThreadHasUnscopedSurfaceFlingerAccess();
-    wp<Layer> parent = fromHandle(args.parentHandle.promote());
+    // We can safely promote the parent layer in binder thread because we have a strong reference
+    // to the layer's handle inside this scope.
+    sp<Layer> parent = LayerHandle::getLayer(args.parentHandle.promote());
     if (args.parentHandle != nullptr && parent == nullptr) {
-        ALOGE("Invalid parent handle %p.", args.parentHandle.promote().get());
+        ALOGE("Invalid parent handle %p", args.parentHandle.promote().get());
         args.addToRoot = false;
     }
 
-    int parentId = -1;
-    // We can safely promote the layer in binder thread because we have a strong reference
-    // to the layer's handle inside this scope or we were passed in a sp reference to the layer.
-    sp<Layer> parentSp = parent.promote();
-    if (parentSp != nullptr) {
-        parentId = parentSp->getSequence();
-    }
+    const int parentId = parent ? parent->getSequence() : -1;
     if (mTransactionTracing) {
         mTransactionTracing->onLayerAdded(outResult.handle->localBinder(), layer->sequence,
                                           args.name, args.flags, parentId);
@@ -4571,7 +4571,7 @@
     setTransactionFlags(eTransactionNeeded);
 }
 
-void SurfaceFlinger::onHandleDestroyed(BBinder* handle, sp<Layer>& layer) {
+void SurfaceFlinger::onHandleDestroyed(BBinder* handle, sp<Layer>& layer, uint32_t /* layerId */) {
     Mutex::Autolock lock(mStateLock);
     markLayerPendingRemovalLocked(layer);
     mBufferCountTracker.remove(handle);
@@ -6176,7 +6176,7 @@
     {
         Mutex::Autolock lock(mStateLock);
 
-        parent = fromHandle(args.layerHandle).promote();
+        parent = LayerHandle::getLayer(args.layerHandle);
         if (parent == nullptr) {
             ALOGE("captureLayers called with an invalid or removed parent");
             return NAME_NOT_FOUND;
@@ -6207,7 +6207,7 @@
         reqSize = ui::Size(crop.width() * args.frameScaleX, crop.height() * args.frameScaleY);
 
         for (const auto& handle : args.excludeHandles) {
-            sp<Layer> excludeLayer = fromHandle(handle).promote();
+            sp<Layer> excludeLayer = LayerHandle::getLayer(handle);
             if (excludeLayer != nullptr) {
                 excludeLayers.emplace(excludeLayer);
             } else {
@@ -6723,10 +6723,6 @@
     return NO_ERROR;
 }
 
-wp<Layer> SurfaceFlinger::fromHandle(const sp<IBinder>& handle) const {
-    return Layer::fromHandle(handle);
-}
-
 void SurfaceFlinger::onLayerFirstRef(Layer* layer) {
     mNumLayers++;
     if (!layer->isRemovedFromCurrentState()) {
@@ -7015,7 +7011,7 @@
     for (const auto& mirrorDisplay : mirrorDisplays) {
         // Set mirror layer's default layer stack to -1 so it doesn't end up rendered on a display
         // accidentally.
-        sp<Layer> rootMirrorLayer = Layer::fromHandle(mirrorDisplay.rootHandle).promote();
+        sp<Layer> rootMirrorLayer = LayerHandle::getLayer(mirrorDisplay.rootHandle);
         rootMirrorLayer->setLayerStack(ui::LayerStack::fromValue(-1));
         for (const auto& layer : mDrawingState.layersSortedByZ) {
             if (layer->getLayerStack() != mirrorDisplay.layerStack ||
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 9ffe6ab..85c194b 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -273,6 +273,11 @@
     void removeHierarchyFromOffscreenLayers(Layer* layer);
     void removeFromOffscreenLayers(Layer* layer);
 
+    // Called when all clients have released all their references to
+    // this layer. The layer may still be kept alive by its parents but
+    // the client can no longer modify this layer directly.
+    void onHandleDestroyed(BBinder* handle, sp<Layer>& layer, uint32_t layerId);
+
     // TODO: Remove atomic if move dtor to main thread CL lands
     std::atomic<uint32_t> mNumClones;
 
@@ -280,12 +285,6 @@
         return mTransactionCallbackInvoker;
     }
 
-    // Converts from a binder handle to a Layer
-    // Returns nullptr if the handle does not point to an existing layer.
-    // Otherwise, returns a weak reference so that callers off the main-thread
-    // won't accidentally hold onto the last strong reference.
-    wp<Layer> fromHandle(const sp<IBinder>& handle) const;
-
     // If set, disables reusing client composition buffers. This can be set by
     // debug.sf.disable_client_composition_cache
     bool mDisableClientCompositionCache = false;
@@ -768,10 +767,6 @@
     status_t mirrorDisplay(DisplayId displayId, const LayerCreationArgs& args,
                            gui::CreateSurfaceResult& outResult);
 
-    // called when all clients have released all their references to
-    // this layer meaning it is entirely safe to destroy all
-    // resources associated to this layer.
-    void onHandleDestroyed(BBinder* handle, sp<Layer>& layer);
     void markLayerPendingRemovalLocked(const sp<Layer>& layer);
 
     // add a layer to SurfaceFlinger
diff --git a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzer.cpp b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzer.cpp
index 22d80ca..14384a7 100644
--- a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzer.cpp
+++ b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzer.cpp
@@ -150,7 +150,7 @@
 
     sp<IBinder> handle = defaultServiceManager()->checkService(
             String16(mFdp.ConsumeRandomLengthString().c_str()));
-    mFlinger->fromHandle(handle);
+    LayerHandle::getLayer(handle);
     mFlinger->disableExpensiveRendering();
 }
 
diff --git a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
index 99279dc..e555867 100644
--- a/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
+++ b/services/surfaceflinger/fuzzer/surfaceflinger_fuzzers_utils.h
@@ -34,6 +34,7 @@
 #include "DisplayHardware/ComposerHal.h"
 #include "FrameTimeline/FrameTimeline.h"
 #include "FrameTracer/FrameTracer.h"
+#include "FrontEnd/LayerHandle.h"
 #include "Layer.h"
 #include "NativeWindowSurface.h"
 #include "Scheduler/EventThread.h"
@@ -766,7 +767,7 @@
     auto& mutableDisplays() { return mFlinger->mDisplays; }
     auto& mutableDrawingState() { return mFlinger->mDrawingState; }
 
-    auto fromHandle(const sp<IBinder> &handle) { return mFlinger->fromHandle(handle); }
+    auto fromHandle(const sp<IBinder> &handle) { return LayerHandle::getLayer(handle); }
 
     ~TestableSurfaceFlinger() {
         mutableDisplays().clear();
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 89812aa..7f471bc 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -34,6 +34,7 @@
 #include "FakeVsyncConfiguration.h"
 #include "FrameTracer/FrameTracer.h"
 #include "FrontEnd/LayerCreationArgs.h"
+#include "FrontEnd/LayerHandle.h"
 #include "Layer.h"
 #include "NativeWindowSurface.h"
 #include "Scheduler/MessageQueue.h"
@@ -530,9 +531,7 @@
     auto& mutablePrimaryHwcDisplayId() { return getHwComposer().mPrimaryHwcDisplayId; }
     auto& mutableActiveDisplayId() { return mFlinger->mActiveDisplayId; }
 
-    auto fromHandle(const sp<IBinder>& handle) {
-        return mFlinger->fromHandle(handle);
-    }
+    auto fromHandle(const sp<IBinder>& handle) { return LayerHandle::getLayer(handle); }
 
     ~TestableSurfaceFlinger() {
         // All these pointer and container clears help ensure that GMock does
diff --git a/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp b/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp
index de84faa..9888f00 100644
--- a/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp
+++ b/services/surfaceflinger/tests/unittests/TransactionApplicationTest.cpp
@@ -294,7 +294,7 @@
 TEST_F(TransactionApplicationTest, FromHandle) {
     sp<IBinder> badHandle;
     auto ret = mFlinger.fromHandle(badHandle);
-    EXPECT_EQ(nullptr, ret.promote().get());
+    EXPECT_EQ(nullptr, ret.get());
 }
 
 class LatchUnsignaledTest : public TransactionApplicationTest {