1 /* 2 * Copyright (C) 2020 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #include <cstdint> 20 #include <deque> 21 22 #include <compositionengine/LayerFE.h> 23 #include <renderengine/DisplaySettings.h> 24 #include <renderengine/LayerSettings.h> 25 26 namespace android { 27 28 namespace compositionengine::impl { 29 30 // The cache is used to skip duplicate client composition requests. We do so by keeping track 31 // of every composition request and the buffer that the request is rendered into. During the 32 // next composition request, if the request matches what was rendered into the buffer, then 33 // we can skip of the request, pass back an empty fence, and let HWC use the previous render 34 // result. 35 // 36 // The cache is a mapping of the RenderSurface buffer id (unique per process) and a snapshot of 37 // the composition request. We need to make sure the request, including the order of the 38 // layers, do not change from call to call. The snapshot removes strong references to the 39 // client buffer id so we don't extend the lifetime of the buffer by storing it in the cache. 40 class ClientCompositionRequestCache { 41 public: ClientCompositionRequestCache(uint32_t cacheSize)42 explicit ClientCompositionRequestCache(uint32_t cacheSize) : mMaxCacheSize(cacheSize){}; 43 ~ClientCompositionRequestCache() = default; 44 bool exists(uint64_t bufferId, const renderengine::DisplaySettings& display, 45 const std::vector<LayerFE::LayerSettings>& layerSettings) const; 46 void add(uint64_t bufferId, const renderengine::DisplaySettings& display, 47 const std::vector<LayerFE::LayerSettings>& layerSettings); 48 void remove(uint64_t bufferId); 49 50 private: 51 uint32_t mMaxCacheSize; 52 struct ClientCompositionRequest { 53 renderengine::DisplaySettings display; 54 std::vector<LayerFE::LayerSettings> layerSettings; 55 ClientCompositionRequest(const renderengine::DisplaySettings& _display, 56 const std::vector<LayerFE::LayerSettings>& _layerSettings); 57 bool equals(const renderengine::DisplaySettings& _display, 58 const std::vector<LayerFE::LayerSettings>& _layerSettings) const; 59 }; 60 61 // Cache of requests, keyed by corresponding GraphicBuffer ID. 62 std::deque<std::pair<uint64_t /* bufferId */, ClientCompositionRequest>> mCache; 63 }; 64 65 } // namespace compositionengine::impl 66 } // namespace android 67