diff --git a/libs/gui/IGraphicBufferProducerFlattenables.cpp b/libs/gui/IGraphicBufferProducerFlattenables.cpp
new file mode 100644
index 0000000..c8b9b67
--- /dev/null
+++ b/libs/gui/IGraphicBufferProducerFlattenables.cpp
@@ -0,0 +1,413 @@
+/*
+ * Copyright 2021 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 <inttypes.h>
+#include <gui/IGraphicBufferProducer.h>
+
+namespace android {
+
+constexpr size_t IGraphicBufferProducer::QueueBufferInput::minFlattenedSize() {
+    return sizeof(timestamp) +
+            sizeof(isAutoTimestamp) +
+            sizeof(dataSpace) +
+            sizeof(crop) +
+            sizeof(scalingMode) +
+            sizeof(transform) +
+            sizeof(stickyTransform) +
+            sizeof(getFrameTimestamps) +
+            sizeof(slot);
+}
+
+size_t IGraphicBufferProducer::QueueBufferInput::getFlattenedSize() const {
+    return minFlattenedSize() +
+            fence->getFlattenedSize() +
+            surfaceDamage.getFlattenedSize() +
+            hdrMetadata.getFlattenedSize();
+}
+
+size_t IGraphicBufferProducer::QueueBufferInput::getFdCount() const {
+    return fence->getFdCount();
+}
+
+status_t IGraphicBufferProducer::QueueBufferInput::flatten(
+        void*& buffer, size_t& size, int*& fds, size_t& count) const
+{
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::write(buffer, size, timestamp);
+    FlattenableUtils::write(buffer, size, isAutoTimestamp);
+    FlattenableUtils::write(buffer, size, dataSpace);
+    FlattenableUtils::write(buffer, size, crop);
+    FlattenableUtils::write(buffer, size, scalingMode);
+    FlattenableUtils::write(buffer, size, transform);
+    FlattenableUtils::write(buffer, size, stickyTransform);
+    FlattenableUtils::write(buffer, size, getFrameTimestamps);
+
+    status_t result = fence->flatten(buffer, size, fds, count);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    result = surfaceDamage.flatten(buffer, size);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    FlattenableUtils::advance(buffer, size, surfaceDamage.getFlattenedSize());
+    result = hdrMetadata.flatten(buffer, size);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    FlattenableUtils::advance(buffer, size, hdrMetadata.getFlattenedSize());
+    FlattenableUtils::write(buffer, size, slot);
+    return NO_ERROR;
+}
+
+status_t IGraphicBufferProducer::QueueBufferInput::unflatten(
+        void const*& buffer, size_t& size, int const*& fds, size_t& count)
+{
+    if (size < minFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, timestamp);
+    FlattenableUtils::read(buffer, size, isAutoTimestamp);
+    FlattenableUtils::read(buffer, size, dataSpace);
+    FlattenableUtils::read(buffer, size, crop);
+    FlattenableUtils::read(buffer, size, scalingMode);
+    FlattenableUtils::read(buffer, size, transform);
+    FlattenableUtils::read(buffer, size, stickyTransform);
+    FlattenableUtils::read(buffer, size, getFrameTimestamps);
+
+    fence = new Fence();
+    status_t result = fence->unflatten(buffer, size, fds, count);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    result = surfaceDamage.unflatten(buffer, size);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    FlattenableUtils::advance(buffer, size, surfaceDamage.getFlattenedSize());
+    result =  hdrMetadata.unflatten(buffer, size);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    FlattenableUtils::advance(buffer, size, hdrMetadata.getFlattenedSize());
+    FlattenableUtils::read(buffer, size, slot);
+    return NO_ERROR;
+}
+
+////////////////////////////////////////////////////////////////////////
+constexpr size_t IGraphicBufferProducer::QueueBufferOutput::minFlattenedSize() {
+    return sizeof(width) + sizeof(height) + sizeof(transformHint) + sizeof(numPendingBuffers) +
+            sizeof(nextFrameNumber) + sizeof(bufferReplaced) + sizeof(maxBufferCount) +
+            sizeof(result);
+}
+size_t IGraphicBufferProducer::QueueBufferOutput::getFlattenedSize() const {
+    return minFlattenedSize() + frameTimestamps.getFlattenedSize();
+}
+
+size_t IGraphicBufferProducer::QueueBufferOutput::getFdCount() const {
+    return frameTimestamps.getFdCount();
+}
+
+status_t IGraphicBufferProducer::QueueBufferOutput::flatten(
+        void*& buffer, size_t& size, int*& fds, size_t& count) const
+{
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::write(buffer, size, width);
+    FlattenableUtils::write(buffer, size, height);
+    FlattenableUtils::write(buffer, size, transformHint);
+    FlattenableUtils::write(buffer, size, numPendingBuffers);
+    FlattenableUtils::write(buffer, size, nextFrameNumber);
+    FlattenableUtils::write(buffer, size, bufferReplaced);
+    FlattenableUtils::write(buffer, size, maxBufferCount);
+
+    status_t result = frameTimestamps.flatten(buffer, size, fds, count);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    FlattenableUtils::write(buffer, size, result);
+    return NO_ERROR;
+}
+
+status_t IGraphicBufferProducer::QueueBufferOutput::unflatten(
+        void const*& buffer, size_t& size, int const*& fds, size_t& count)
+{
+    if (size < minFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, width);
+    FlattenableUtils::read(buffer, size, height);
+    FlattenableUtils::read(buffer, size, transformHint);
+    FlattenableUtils::read(buffer, size, numPendingBuffers);
+    FlattenableUtils::read(buffer, size, nextFrameNumber);
+    FlattenableUtils::read(buffer, size, bufferReplaced);
+    FlattenableUtils::read(buffer, size, maxBufferCount);
+
+    status_t result = frameTimestamps.unflatten(buffer, size, fds, count);
+    if (result != NO_ERROR) {
+        return result;
+    }
+    FlattenableUtils::read(buffer, size, result);
+    return NO_ERROR;
+}
+
+////////////////////////////////////////////////////////////////////////
+constexpr size_t IGraphicBufferProducer::RequestBufferOutput::minFlattenedSize() {
+    return sizeof(result) +
+            sizeof(int32_t); // IsBufferNull
+}
+
+size_t IGraphicBufferProducer::RequestBufferOutput::getFlattenedSize() const {
+    return minFlattenedSize() + (buffer == nullptr ? 0 : buffer->getFlattenedSize());
+}
+
+size_t IGraphicBufferProducer::RequestBufferOutput::getFdCount() const {
+    return (buffer == nullptr ? 0 : buffer->getFdCount());
+}
+
+status_t IGraphicBufferProducer::RequestBufferOutput::flatten(
+        void*& fBuffer, size_t& size, int*& fds, size_t& count) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::write(fBuffer, size, result);
+    const int32_t isBufferNull = (buffer == nullptr ? 1 : 0);
+    FlattenableUtils::write(fBuffer, size, isBufferNull);
+
+    if (!isBufferNull) {
+        status_t status = buffer->flatten(fBuffer, size, fds, count);
+        if (status != NO_ERROR) {
+            return status;
+        }
+    }
+    return NO_ERROR;
+}
+
+status_t IGraphicBufferProducer::RequestBufferOutput::unflatten(
+        void const*& fBuffer, size_t& size, int const*& fds, size_t& count) {
+    if (size < minFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(fBuffer, size, result);
+    int32_t isBufferNull = 0;
+    FlattenableUtils::read(fBuffer, size, isBufferNull);
+    buffer = new GraphicBuffer();
+    if (!isBufferNull) {
+        status_t status = buffer->unflatten(fBuffer, size, fds, count);
+        if (status != NO_ERROR) {
+            return status;
+        }
+    }
+    return NO_ERROR;
+}
+
+////////////////////////////////////////////////////////////////////////
+
+size_t IGraphicBufferProducer::DequeueBufferInput::getFlattenedSize() const {
+    return sizeof(width) + sizeof(height) + sizeof(format) + sizeof(usage) +
+            sizeof(int32_t/*getTimestamps*/);
+}
+
+status_t IGraphicBufferProducer::DequeueBufferInput::flatten(void* buffer, size_t size) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::write(buffer, size, width);
+    FlattenableUtils::write(buffer, size, height);
+    FlattenableUtils::write(buffer, size, format);
+    FlattenableUtils::write(buffer, size, usage);
+    const int32_t getTimestampsInt = (getTimestamps ? 1 : 0);
+    FlattenableUtils::write(buffer, size, getTimestampsInt);
+
+    return NO_ERROR;
+}
+
+status_t IGraphicBufferProducer::DequeueBufferInput::unflatten(void const* buffer, size_t size) {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, width);
+    FlattenableUtils::read(buffer, size, height);
+    FlattenableUtils::read(buffer, size, format);
+    FlattenableUtils::read(buffer, size, usage);
+    int32_t getTimestampsInt = 0;
+    FlattenableUtils::read(buffer, size, getTimestampsInt);
+    getTimestamps = (getTimestampsInt == 1);
+
+    return NO_ERROR;
+}
+
+////////////////////////////////////////////////////////////////////////
+
+constexpr size_t IGraphicBufferProducer::DequeueBufferOutput::minFlattenedSize() {
+    return sizeof(result) + sizeof(slot) + sizeof(bufferAge) + sizeof(int32_t/*hasTimestamps*/);
+}
+
+size_t IGraphicBufferProducer::DequeueBufferOutput::getFlattenedSize() const {
+    return minFlattenedSize() +
+            fence->getFlattenedSize() +
+            (timestamps.has_value() ? timestamps->getFlattenedSize() : 0);
+}
+
+size_t IGraphicBufferProducer::DequeueBufferOutput::getFdCount() const {
+    return fence->getFdCount() +
+            (timestamps.has_value() ? timestamps->getFdCount() : 0);
+}
+
+status_t IGraphicBufferProducer::DequeueBufferOutput::flatten(
+        void*& buffer, size_t& size, int*& fds, size_t& count) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::write(buffer, size, result);
+    FlattenableUtils::write(buffer, size, slot);
+    FlattenableUtils::write(buffer, size, bufferAge);
+    status_t status = fence->flatten(buffer, size, fds, count);
+    if (status != NO_ERROR) {
+        return result;
+    }
+    const int32_t hasTimestamps = timestamps.has_value() ? 1 : 0;
+    FlattenableUtils::write(buffer, size, hasTimestamps);
+    if (timestamps.has_value()) {
+        status = timestamps->flatten(buffer, size, fds, count);
+    }
+    return status;
+}
+
+status_t IGraphicBufferProducer::DequeueBufferOutput::unflatten(
+        void const*& buffer, size_t& size, int const*& fds, size_t& count) {
+    if (size < minFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, result);
+    FlattenableUtils::read(buffer, size, slot);
+    FlattenableUtils::read(buffer, size, bufferAge);
+
+    fence = new Fence();
+    status_t status = fence->unflatten(buffer, size, fds, count);
+    if (status != NO_ERROR) {
+        return status;
+    }
+    int32_t hasTimestamps = 0;
+    FlattenableUtils::read(buffer, size, hasTimestamps);
+    if (hasTimestamps) {
+        timestamps.emplace();
+        status = timestamps->unflatten(buffer, size, fds, count);
+    }
+    return status;
+}
+
+////////////////////////////////////////////////////////////////////////
+
+size_t IGraphicBufferProducer::AttachBufferOutput::getFlattenedSize() const {
+    return sizeof(result) + sizeof(slot);
+}
+
+status_t IGraphicBufferProducer::AttachBufferOutput::flatten(void* buffer, size_t size) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::write(buffer, size, result);
+    FlattenableUtils::write(buffer, size, slot);
+
+    return NO_ERROR;
+}
+
+status_t IGraphicBufferProducer::AttachBufferOutput::unflatten(void const* buffer, size_t size) {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::read(buffer, size, result);
+    FlattenableUtils::read(buffer, size, slot);
+
+    return NO_ERROR;
+}
+
+////////////////////////////////////////////////////////////////////////
+
+constexpr size_t IGraphicBufferProducer::CancelBufferInput::minFlattenedSize() {
+    return sizeof(slot);
+}
+
+size_t IGraphicBufferProducer::CancelBufferInput::getFlattenedSize() const {
+    return minFlattenedSize() + fence->getFlattenedSize();
+}
+
+size_t IGraphicBufferProducer::CancelBufferInput::getFdCount() const {
+    return fence->getFdCount();
+}
+
+status_t IGraphicBufferProducer::CancelBufferInput::flatten(
+        void*& buffer, size_t& size, int*& fds, size_t& count) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::write(buffer, size, slot);
+    return fence->flatten(buffer, size, fds, count);
+}
+
+status_t IGraphicBufferProducer::CancelBufferInput::unflatten(
+        void const*& buffer, size_t& size, int const*& fds, size_t& count) {
+    if (size < minFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, slot);
+
+    fence = new Fence();
+    return fence->unflatten(buffer, size, fds, count);
+}
+
+////////////////////////////////////////////////////////////////////////
+
+size_t IGraphicBufferProducer::QueryOutput::getFlattenedSize() const {
+    return sizeof(result) + sizeof(value);
+}
+
+status_t IGraphicBufferProducer::QueryOutput::flatten(void* buffer, size_t size) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::write(buffer, size, result);
+    FlattenableUtils::write(buffer, size, value);
+
+    return NO_ERROR;
+}
+
+status_t IGraphicBufferProducer::QueryOutput::unflatten(void const* buffer, size_t size) {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+    FlattenableUtils::read(buffer, size, result);
+    FlattenableUtils::read(buffer, size, value);
+
+    return NO_ERROR;
+}
+
+} // namespace android