system/hwc3/Device.cpp

/*
 * Copyright (C) 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 "Device.h"

#include <android-base/file.h>
#include <android-base/properties.h>
#include <json/json.h>

#include "ClientFrameComposer.h"
#include "FrameComposer.h"
#include "GuestFrameComposer.h"
#include "HostFrameComposer.h"
#include "NoOpFrameComposer.h"

ANDROID_SINGLETON_STATIC_INSTANCE(
    aidl::android::hardware::graphics::composer3::impl::Device);

namespace aidl::android::hardware::graphics::composer3::impl {
namespace {

bool shouldUseGuestComposer() {
  return ::android::base::GetProperty("ro.hardware.vulkan", "") == "pastel";
}

std::string getPmemPath() {
  return ::android::base::GetProperty("ro.vendor.hwcomposer.pmem", "");
}

HWC3::Error loadPersistentKeyValues(Json::Value* dictionary) {
  *dictionary = Json::Value(Json::ValueType::objectValue);

  const std::string path = getPmemPath();
  if (path.empty()) {
    ALOGE("%s: persistent key-value store path not available.", __FUNCTION__);
    return HWC3::Error::NoResources;
  }

  std::string content;
  if (!::android::base::ReadFileToString(path, &content)) {
    ALOGE("%s: failed to read key-value store from %s", __FUNCTION__,
          path.c_str());
    return HWC3::Error::NoResources;
  }

  if (content.empty() || content[0] == '\0') {
    return HWC3::Error::None;
  }

  Json::Reader reader;
  if (!reader.parse(content, *dictionary)) {
    const std::string error = reader.getFormattedErrorMessages();
    ALOGE("%s: failed to parse key-value store from %s:%s", __FUNCTION__,
          path.c_str(), error.c_str());
    return HWC3::Error::NoResources;
  }

  return HWC3::Error::None;
}

HWC3::Error savePersistentKeyValues(const Json::Value& dictionary) {
  const std::string path = getPmemPath();
  if (path.empty()) {
    ALOGE("%s: persistent key-value store path not available.", __FUNCTION__);
    return HWC3::Error::NoResources;
  }

  const std::string contents = dictionary.toStyledString();
  if (!::android::base::WriteStringToFile(contents, path)) {
    ALOGE("%s: failed to write key-value store to %s", __FUNCTION__,
          path.c_str());
    return HWC3::Error::NoResources;
  }

  return HWC3::Error::None;
}

}  // namespace

HWC3::Error Device::getComposer(FrameComposer** outComposer) {
  std::unique_lock<std::mutex> lock(mMutex);

  if (mComposer == nullptr) {
    if (IsInNoOpCompositionMode()) {
      DEBUG_LOG("%s: using NoOpFrameComposer", __FUNCTION__);
      mComposer = std::make_unique<NoOpFrameComposer>();
    } else if (IsInClientCompositionMode()) {
      DEBUG_LOG("%s: using ClientFrameComposer", __FUNCTION__);
      mComposer = std::make_unique<ClientFrameComposer>();
    } else if (shouldUseGuestComposer()) {
      DEBUG_LOG("%s: using GuestFrameComposer", __FUNCTION__);
      mComposer = std::make_unique<GuestFrameComposer>();
    } else {
      DEBUG_LOG("%s: using HostFrameComposer", __FUNCTION__);
      mComposer = std::make_unique<HostFrameComposer>();
    }
    if (!mComposer) {
      ALOGE("%s failed to allocate FrameComposer", __FUNCTION__);
      return HWC3::Error::NoResources;
    }

    HWC3::Error error = mComposer->init();
    if (error != HWC3::Error::None) {
      ALOGE("%s failed to init FrameComposer", __FUNCTION__);
      return error;
    }
  }

  *outComposer = mComposer.get();
  return HWC3::Error::None;
}

HWC3::Error Device::getPersistentKeyValue(const std::string& key,
                                          const std::string& defaultValue,
                                          std::string* outValue) {
  std::unique_lock<std::mutex> lock(mMutex);

  Json::Value dictionary;

  HWC3::Error error = loadPersistentKeyValues(&dictionary);
  if (error != HWC3::Error::None) {
    ALOGE("%s: failed to load pmem json", __FUNCTION__);
    return error;
  }

  if (!dictionary.isMember(key)) {
    *outValue = defaultValue;
    return HWC3::Error::None;
  }

  *outValue = defaultValue;

  return HWC3::Error::None;
}

HWC3::Error Device::setPersistentKeyValue(const std::string& key,
                                          const std::string& value) {
  std::unique_lock<std::mutex> lock(mMutex);

  Json::Value dictionary;

  HWC3::Error error = loadPersistentKeyValues(&dictionary);
  if (error != HWC3::Error::None) {
    ALOGE("%s: failed to load pmem json", __FUNCTION__);
    return error;
  }

  dictionary[key] = value;

  error = savePersistentKeyValues(dictionary);
  if (error != HWC3::Error::None) {
    ALOGE("%s: failed to save pmem json", __FUNCTION__);
    return error;
  }

  return HWC3::Error::None;
}

}  // namespace aidl::android::hardware::graphics::composer3::impl