diff --git a/graphics/composer/aidl/include/android/hardware/graphics/composer3/ComposerServiceWriter.h b/graphics/composer/aidl/include/android/hardware/graphics/composer3/ComposerServiceWriter.h
new file mode 100644
index 0000000..34cda6a
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+++ b/graphics/composer/aidl/include/android/hardware/graphics/composer3/ComposerServiceWriter.h
@@ -0,0 +1,128 @@
+/*
+ * Copyright 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.
+ */
+
+#pragma once
+
+#include <aidl/android/hardware/graphics/composer3/CommandResultPayload.h>
+#include <aidl/android/hardware/graphics/composer3/IComposerClient.h>
+#include <inttypes.h>
+#include <string.h>
+
+#include <algorithm>
+#include <limits>
+#include <memory>
+#include <vector>
+
+#include "Util.h"
+
+namespace aidl::android::hardware::graphics::composer3::impl {
+
+class ComposerServiceWriter {
+  public:
+    ComposerServiceWriter() { reset(); }
+
+    virtual ~ComposerServiceWriter() { reset(); }
+
+    void reset() { mCommandsResults.clear(); }
+
+    void setError(int32_t index, int32_t errorCode) {
+        CommandError error;
+        error.commandIndex = index;
+        error.errorCode = errorCode;
+        mCommandsResults.emplace_back(std::move(error));
+    }
+
+    void setPresentOrValidateResult(int64_t display, PresentOrValidate::Result result) {
+        PresentOrValidate presentOrValidate;
+        presentOrValidate.display = display;
+        presentOrValidate.result = result;
+        mCommandsResults.emplace_back(std::move(presentOrValidate));
+    }
+
+    void setChangedCompositionTypes(int64_t display, const std::vector<int64_t>& layers,
+                                    const std::vector<Composition>& types) {
+        ChangedCompositionTypes changedCompositionTypes;
+        changedCompositionTypes.display = display;
+        changedCompositionTypes.layers.reserve(layers.size());
+        for (int i = 0; i < layers.size(); i++) {
+            auto layer = ChangedCompositionLayer{.layer = layers[i], .composition = types[i]};
+            changedCompositionTypes.layers.emplace_back(std::move(layer));
+        }
+        mCommandsResults.emplace_back(std::move(changedCompositionTypes));
+    }
+
+    void setDisplayRequests(int64_t display, int32_t displayRequestMask,
+                            const std::vector<int64_t>& layers,
+                            const std::vector<int32_t>& layerRequestMasks) {
+        DisplayRequest displayRequest;
+        displayRequest.display = display;
+        displayRequest.mask = displayRequestMask;
+        displayRequest.layerRequests.reserve(layers.size());
+        for (int i = 0; i < layers.size(); i++) {
+            auto layerRequest =
+                    DisplayRequest::LayerRequest{.layer = layers[i], .mask = layerRequestMasks[i]};
+            displayRequest.layerRequests.emplace_back(std::move(layerRequest));
+        }
+        mCommandsResults.emplace_back(std::move(displayRequest));
+    }
+
+    void setPresentFence(int64_t display, ::ndk::ScopedFileDescriptor presentFence) {
+        if (presentFence.get() >= 0) {
+            PresentFence presentFenceCommand;
+            presentFenceCommand.fence = std::move(presentFence);
+            presentFenceCommand.display = display;
+            mCommandsResults.emplace_back(std::move(presentFenceCommand));
+        } else {
+            LOG(WARNING) << __func__ << ": invalid present fence " << presentFence.get();
+        }
+    }
+
+    void setReleaseFences(int64_t display, const std::vector<int64_t>& layers,
+                          std::vector<::ndk::ScopedFileDescriptor> releaseFences) {
+        ReleaseFences releaseFencesCommand;
+        releaseFencesCommand.display = display;
+        for (int i = 0; i < layers.size(); i++) {
+            if (releaseFences[i].get() >= 0) {
+                ReleaseFences::Layer layer;
+                layer.layer = layers[i];
+                layer.fence = std::move(releaseFences[i]);
+                releaseFencesCommand.layers.emplace_back(std::move(layer));
+            } else {
+                LOG(WARNING) << __func__ << ": invalid release fence " << releaseFences[i].get();
+            }
+        }
+        mCommandsResults.emplace_back(std::move(releaseFencesCommand));
+    }
+
+    void setClientTargetProperty(int64_t display, const ClientTargetProperty& clientTargetProperty,
+                                 float brightness, const DimmingStage& dimmingStage) {
+        ClientTargetPropertyWithBrightness clientTargetPropertyWithBrightness;
+        clientTargetPropertyWithBrightness.display = display;
+        clientTargetPropertyWithBrightness.clientTargetProperty = clientTargetProperty;
+        clientTargetPropertyWithBrightness.brightness = brightness;
+        clientTargetPropertyWithBrightness.dimmingStage = dimmingStage;
+        mCommandsResults.emplace_back(std::move(clientTargetPropertyWithBrightness));
+    }
+
+    std::vector<CommandResultPayload> getPendingCommandResults() {
+        return std::move(mCommandsResults);
+    }
+
+  private:
+    std::vector<CommandResultPayload> mCommandsResults;
+};
+
+}  // namespace aidl::android::hardware::graphics::composer3::impl
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