libs/gui/tests/DisplayEventStructLayout_test.cpp

/*
 * Copyright (C) 2020 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 <gtest/gtest.h>
#include <gui/DisplayEventReceiver.h>

namespace android::test {

#define CHECK_OFFSET(type, member, expected_offset) \
    static_assert((offsetof(type, member) == (expected_offset)))

TEST(DisplayEventStructLayoutTest, TestEventAlignment) {
    static_assert(std::is_pod<DisplayEventReceiver::Event::VSync>::value);
    CHECK_OFFSET(DisplayEventReceiver::Event, vsync, 24);
    CHECK_OFFSET(DisplayEventReceiver::Event, hotplug, 24);
    CHECK_OFFSET(DisplayEventReceiver::Event, modeChange, 24);

    CHECK_OFFSET(DisplayEventReceiver::Event::Header, type, 0);
    CHECK_OFFSET(DisplayEventReceiver::Event::Header, displayId, 8);
    CHECK_OFFSET(DisplayEventReceiver::Event::Header, timestamp, 16);

    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, count, 0);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, vsyncData.frameInterval, 8);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, vsyncData.preferredFrameTimelineIndex, 16);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, vsyncData.frameTimelinesLength, 20);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, vsyncData.frameTimelines, 24);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, vsyncData.frameTimelines[0].vsyncId, 24);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, vsyncData.frameTimelines[0].deadlineTimestamp,
                 32);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync,
                 vsyncData.frameTimelines[0].expectedPresentationTime, 40);
    // Also test the offsets of the last frame timeline. A loop is not used because the non-const
    // index cannot be used in static_assert.
    const int lastFrameTimelineOffset = /* Start of array */ 24 +
            (VsyncEventData::kFrameTimelinesCapacity - 1) * /* Size of FrameTimeline */ 24;
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync,
                 vsyncData.frameTimelines[VsyncEventData::kFrameTimelinesCapacity - 1].vsyncId,
                 lastFrameTimelineOffset);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync,
                 vsyncData.frameTimelines[VsyncEventData::kFrameTimelinesCapacity - 1]
                         .deadlineTimestamp,
                 lastFrameTimelineOffset + 8);
    CHECK_OFFSET(DisplayEventReceiver::Event::VSync,
                 vsyncData.frameTimelines[VsyncEventData::kFrameTimelinesCapacity - 1]
                         .expectedPresentationTime,
                 lastFrameTimelineOffset + 16);

    CHECK_OFFSET(DisplayEventReceiver::Event::Hotplug, connected, 0);

    CHECK_OFFSET(DisplayEventReceiver::Event::ModeChange, modeId, 0);
    CHECK_OFFSET(DisplayEventReceiver::Event::ModeChange, vsyncPeriod, 8);

    CHECK_OFFSET(DisplayEventReceiver::Event::FrameRateOverride, uid, 0);
    CHECK_OFFSET(DisplayEventReceiver::Event::FrameRateOverride, frameRateHz, 8);
}

} // namespace android::test