SF: Move HWComposerBufferCache in to CompositionEngine

This simply moves DisplayHardware/HWComposerBufferCache.* to
CompositionEngine/HwcBufferCache.*, adjusting the existing code to
reference the moved file and namespace.

This is a prelude to moving the layerBE state into CompositionEngine.

Test: atest libsurfaceflinger_unittest libcompositionengine_test
Bug: 121291683
Change-Id: Id1e907963d0453ec7beea285ab384a963c356f89
diff --git a/services/surfaceflinger/DisplayHardware/FramebufferSurface.h b/services/surfaceflinger/DisplayHardware/FramebufferSurface.h
index 18c524f..7f451a5 100644
--- a/services/surfaceflinger/DisplayHardware/FramebufferSurface.h
+++ b/services/surfaceflinger/DisplayHardware/FramebufferSurface.h
@@ -21,10 +21,10 @@
 #include <sys/types.h>
 
 #include <compositionengine/DisplaySurface.h>
+#include <compositionengine/impl/HwcBufferCache.h>
 #include <gui/ConsumerBase.h>
 
 #include "DisplayIdentification.h"
-#include "HWComposerBufferCache.h"
 
 // ---------------------------------------------------------------------------
 namespace android {
@@ -88,7 +88,7 @@
     // Hardware composer, owned by SurfaceFlinger.
     HWComposer& mHwc;
 
-    HWComposerBufferCache mHwcBufferCache;
+    compositionengine::impl::HwcBufferCache mHwcBufferCache;
 
     // Previous buffer to release after getting an updated retire fence
     bool mHasPendingRelease;
diff --git a/services/surfaceflinger/DisplayHardware/HWComposerBufferCache.cpp b/services/surfaceflinger/DisplayHardware/HWComposerBufferCache.cpp
deleted file mode 100644
index a234b63..0000000
--- a/services/surfaceflinger/DisplayHardware/HWComposerBufferCache.cpp
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright (C) 2017 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 "HWComposerBufferCache.h"
-
-#include <gui/BufferQueue.h>
-
-namespace android {
-
-HWComposerBufferCache::HWComposerBufferCache()
-{
-    mBuffers.reserve(BufferQueue::NUM_BUFFER_SLOTS);
-}
-
-void HWComposerBufferCache::getHwcBuffer(int slot,
-        const sp<GraphicBuffer>& buffer,
-        uint32_t* outSlot, sp<GraphicBuffer>* outBuffer)
-{
-    if (slot == BufferQueue::INVALID_BUFFER_SLOT || slot < 0) {
-        // default to slot 0
-        slot = 0;
-    }
-
-    if (static_cast<size_t>(slot) >= mBuffers.size()) {
-        mBuffers.resize(slot + 1);
-    }
-
-    *outSlot = slot;
-
-    if (mBuffers[slot] == buffer) {
-        // already cached in HWC, skip sending the buffer
-        *outBuffer = nullptr;
-    } else {
-        *outBuffer = buffer;
-
-        // update cache
-        mBuffers[slot] = buffer;
-    }
-}
-
-} // namespace android
diff --git a/services/surfaceflinger/DisplayHardware/HWComposerBufferCache.h b/services/surfaceflinger/DisplayHardware/HWComposerBufferCache.h
deleted file mode 100644
index a008ca9..0000000
--- a/services/surfaceflinger/DisplayHardware/HWComposerBufferCache.h
+++ /dev/null
@@ -1,61 +0,0 @@
-/*
- * Copyright (C) 2017 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.
- */
-
-#ifndef ANDROID_SF_HWCOMPOSERBUFFERCACHE_H
-#define ANDROID_SF_HWCOMPOSERBUFFERCACHE_H
-
-#include <stdint.h>
-
-#include <utils/StrongPointer.h>
-
-#include <vector>
-
-namespace android {
-// ---------------------------------------------------------------------------
-
-class GraphicBuffer;
-
-// With HIDLized hwcomposer HAL, the HAL can maintain a buffer cache for each
-// HWC display and layer.  When updating a display target or a layer buffer,
-// we have the option to send the buffer handle over or to request the HAL to
-// retrieve it from its cache.  The latter is cheaper since it eliminates the
-// overhead to transfer the handle over the trasport layer, and the overhead
-// for the HAL to clone and retain the handle.
-//
-// To be able to find out whether a buffer is already in the HAL's cache, we
-// use HWComposerBufferCache to mirror the cache in SF.
-class HWComposerBufferCache {
-public:
-    HWComposerBufferCache();
-
-    // Given a buffer queue slot and buffer, return the HWC cache slot and
-    // buffer to be sent to HWC.
-    //
-    // outBuffer is set to buffer when buffer is not in the HWC cache;
-    // otherwise, outBuffer is set to nullptr.
-    void getHwcBuffer(int slot, const sp<GraphicBuffer>& buffer,
-            uint32_t* outSlot, sp<GraphicBuffer>* outBuffer);
-
-private:
-    // a vector as we expect "slot" to be in the range of [0, 63] (that is,
-    // less than BufferQueue::NUM_BUFFER_SLOTS).
-    std::vector<sp<GraphicBuffer>> mBuffers;
-};
-
-// ---------------------------------------------------------------------------
-}; // namespace android
-
-#endif // ANDROID_SF_HWCOMPOSERBUFFERCACHE_H
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
index 87ae7dd..d6543d1 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
@@ -21,11 +21,11 @@
 #include <string>
 
 #include <compositionengine/DisplaySurface.h>
+#include <compositionengine/impl/HwcBufferCache.h>
 #include <gui/ConsumerBase.h>
 #include <gui/IGraphicBufferProducer.h>
 
 #include "DisplayIdentification.h"
-#include "HWComposerBufferCache.h"
 
 // ---------------------------------------------------------------------------
 namespace android {
@@ -253,7 +253,7 @@
 
     bool mMustRecompose;
 
-    HWComposerBufferCache mHwcBufferCache;
+    compositionengine::impl::HwcBufferCache mHwcBufferCache;
 
     bool mForceHwcCopy;
 };