diff --git a/graphics/composer/2.1/default/Android.bp b/graphics/composer/2.1/default/Android.bp
index 0d63c3c..a366fa2 100644
--- a/graphics/composer/2.1/default/Android.bp
+++ b/graphics/composer/2.1/default/Android.bp
@@ -1,7 +1,28 @@
+cc_library_static {
+    name: "libhwcomposer-client",
+    export_include_dirs: ["."],
+    srcs: ["ComposerClient.cpp"],
+    cppflags: ["-DBINDERIZED"],
+    shared_libs: [
+        "android.hardware.graphics.allocator@2.0",
+        "android.hardware.graphics.composer@2.1",
+        "libbase",
+        "libcutils",
+        "libfmq",
+        "libhardware",
+        "libhidlbase",
+        "libhidltransport",
+        "libhwbinder",
+        "liblog",
+        "libsync",
+        "libutils",
+    ],
+}
+
 cc_library_shared {
     name: "android.hardware.graphics.composer@2.1-impl",
     relative_install_path: "hw",
-    srcs: ["Hwc.cpp", "HwcClient.cpp"],
+    srcs: ["Hwc.cpp", "ComposerClient.cpp"],
     shared_libs: [
         "android.hardware.graphics.allocator@2.0",
         "android.hardware.graphics.composer@2.1",
@@ -21,10 +42,13 @@
 cc_binary {
     name: "android.hardware.graphics.composer@2.1-service",
     relative_install_path: "hw",
-    srcs: ["service.cpp", "Hwc.cpp", "HwcClient.cpp"],
+    srcs: ["service.cpp", "Hwc.cpp"],
     cppflags: ["-DBINDERIZED"],
     init_rc: ["android.hardware.graphics.composer@2.1-service.rc"],
 
+    static_libs: [
+        "libhwcomposer-client",
+    ],
     shared_libs: [
         "android.hardware.graphics.allocator@2.0",
         "android.hardware.graphics.composer@2.1",
diff --git a/graphics/composer/2.1/default/ComposerBase.h b/graphics/composer/2.1/default/ComposerBase.h
new file mode 100644
index 0000000..85b1a4d
--- /dev/null
+++ b/graphics/composer/2.1/default/ComposerBase.h
@@ -0,0 +1,130 @@
+/*
+ * Copyright 2017 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.
+ */
+
+#ifndef ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_COMPOSER_BASE_H
+#define ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_COMPOSER_BASE_H
+
+#include <android/hardware/graphics/composer/2.1/IComposer.h>
+#include <hardware/hwcomposer2.h>
+
+namespace android {
+namespace hardware {
+namespace graphics {
+namespace composer {
+namespace V2_1 {
+namespace implementation {
+
+using android::hardware::graphics::common::V1_0::PixelFormat;
+using android::hardware::graphics::common::V1_0::Transform;
+using android::hardware::graphics::common::V1_0::Dataspace;
+using android::hardware::graphics::common::V1_0::ColorMode;
+using android::hardware::graphics::common::V1_0::ColorTransform;
+using android::hardware::graphics::common::V1_0::Hdr;
+
+class ComposerBase {
+public:
+    virtual ~ComposerBase() {};
+
+    virtual void removeClient() = 0;
+    virtual void enableCallback(bool enable) = 0;
+    virtual uint32_t getMaxVirtualDisplayCount() = 0;
+    virtual Error createVirtualDisplay(uint32_t width, uint32_t height,
+        PixelFormat* format, Display* outDisplay) = 0;
+    virtual Error destroyVirtualDisplay(Display display) = 0;
+    virtual Error createLayer(Display display, Layer* outLayer) = 0;
+    virtual Error destroyLayer(Display display, Layer layer) = 0;
+
+    virtual Error getActiveConfig(Display display, Config* outConfig) = 0;
+    virtual Error getClientTargetSupport(Display display,
+            uint32_t width, uint32_t height,
+            PixelFormat format, Dataspace dataspace) = 0;
+    virtual Error getColorModes(Display display,
+            hidl_vec<ColorMode>* outModes) = 0;
+    virtual Error getDisplayAttribute(Display display, Config config,
+            IComposerClient::Attribute attribute, int32_t* outValue) = 0;
+    virtual Error getDisplayConfigs(Display display,
+            hidl_vec<Config>* outConfigs) = 0;
+    virtual Error getDisplayName(Display display, hidl_string* outName) = 0;
+    virtual Error getDisplayType(Display display,
+            IComposerClient::DisplayType* outType) = 0;
+    virtual Error getDozeSupport(Display display, bool* outSupport) = 0;
+    virtual Error getHdrCapabilities(Display display, hidl_vec<Hdr>* outTypes,
+            float* outMaxLuminance, float* outMaxAverageLuminance,
+            float* outMinLuminance) = 0;
+
+    virtual Error setActiveConfig(Display display, Config config) = 0;
+    virtual Error setColorMode(Display display, ColorMode mode) = 0;
+    virtual Error setPowerMode(Display display,
+            IComposerClient::PowerMode mode) = 0;
+    virtual Error setVsyncEnabled(Display display,
+            IComposerClient::Vsync enabled) = 0;
+
+    virtual Error setColorTransform(Display display, const float* matrix,
+            int32_t hint) = 0;
+    virtual Error setClientTarget(Display display, buffer_handle_t target,
+            int32_t acquireFence, int32_t dataspace,
+            const std::vector<hwc_rect_t>& damage) = 0;
+    virtual Error setOutputBuffer(Display display, buffer_handle_t buffer,
+            int32_t releaseFence) = 0;
+    virtual Error validateDisplay(Display display,
+            std::vector<Layer>* outChangedLayers,
+            std::vector<IComposerClient::Composition>* outCompositionTypes,
+            uint32_t* outDisplayRequestMask,
+            std::vector<Layer>* outRequestedLayers,
+            std::vector<uint32_t>* outRequestMasks) = 0;
+    virtual Error acceptDisplayChanges(Display display) = 0;
+    virtual Error presentDisplay(Display display, int32_t* outPresentFence,
+            std::vector<Layer>* outLayers,
+            std::vector<int32_t>* outReleaseFences) = 0;
+
+    virtual Error setLayerCursorPosition(Display display, Layer layer,
+            int32_t x, int32_t y) = 0;
+    virtual Error setLayerBuffer(Display display, Layer layer,
+            buffer_handle_t buffer, int32_t acquireFence) = 0;
+    virtual Error setLayerSurfaceDamage(Display display, Layer layer,
+            const std::vector<hwc_rect_t>& damage) = 0;
+    virtual Error setLayerBlendMode(Display display, Layer layer,
+            int32_t mode) = 0;
+    virtual Error setLayerColor(Display display, Layer layer,
+            IComposerClient::Color color) = 0;
+    virtual Error setLayerCompositionType(Display display, Layer layer,
+            int32_t type) = 0;
+    virtual Error setLayerDataspace(Display display, Layer layer,
+            int32_t dataspace) = 0;
+    virtual Error setLayerDisplayFrame(Display display, Layer layer,
+            const hwc_rect_t& frame) = 0;
+    virtual Error setLayerPlaneAlpha(Display display, Layer layer,
+            float alpha) = 0;
+    virtual Error setLayerSidebandStream(Display display, Layer layer,
+            buffer_handle_t stream) = 0;
+    virtual Error setLayerSourceCrop(Display display, Layer layer,
+            const hwc_frect_t& crop) = 0;
+    virtual Error setLayerTransform(Display display, Layer layer,
+            int32_t transform) = 0;
+    virtual Error setLayerVisibleRegion(Display display, Layer layer,
+            const std::vector<hwc_rect_t>& visible) = 0;
+    virtual Error setLayerZOrder(Display display, Layer layer,
+            uint32_t z) = 0;
+};
+
+}  // namespace implementation
+}  // namespace V2_1
+}  // namespace composer
+}  // namespace graphics
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_COMPOSER_BASE_H
diff --git a/graphics/composer/2.1/default/HwcClient.cpp b/graphics/composer/2.1/default/ComposerClient.cpp
similarity index 76%
rename from graphics/composer/2.1/default/HwcClient.cpp
rename to graphics/composer/2.1/default/ComposerClient.cpp
index edd161a..49415ee 100644
--- a/graphics/composer/2.1/default/HwcClient.cpp
+++ b/graphics/composer/2.1/default/ComposerClient.cpp
@@ -20,8 +20,8 @@
 #include <hardware/gralloc1.h>
 #include <log/log.h>
 
+#include "ComposerClient.h"
 #include "Hwc.h"
-#include "HwcClient.h"
 #include "IComposerCommandBuffer.h"
 
 namespace android {
@@ -230,15 +230,12 @@
     }
 }
 
-HwcClient::HwcClient(HwcHal& hal)
-    : mHal(hal), mReader(*this), mWriter(kWriterInitialSize)
+ComposerClient::ComposerClient(ComposerBase& hal)
+    : mHal(hal), mWriter(kWriterInitialSize)
 {
-    if (!sHandleImporter.initialize()) {
-        LOG_ALWAYS_FATAL("failed to initialize handle importer");
-    }
 }
 
-HwcClient::~HwcClient()
+ComposerClient::~ComposerClient()
 {
     mHal.enableCallback(false);
     mHal.removeClient();
@@ -264,7 +261,15 @@
     sHandleImporter.cleanup();
 }
 
-void HwcClient::onHotplug(Display display,
+void ComposerClient::initialize()
+{
+    mReader = createCommandReader();
+    if (!sHandleImporter.initialize()) {
+        LOG_ALWAYS_FATAL("failed to initialize handle importer");
+    }
+}
+
+void ComposerClient::onHotplug(Display display,
         IComposerCallback::Connection connected)
 {
     {
@@ -280,17 +285,18 @@
     mCallback->onHotplug(display, connected);
 }
 
-void HwcClient::onRefresh(Display display)
+void ComposerClient::onRefresh(Display display)
 {
     mCallback->onRefresh(display);
 }
 
-void HwcClient::onVsync(Display display, int64_t timestamp)
+void ComposerClient::onVsync(Display display, int64_t timestamp)
 {
     mCallback->onVsync(display, timestamp);
 }
 
-Return<void> HwcClient::registerCallback(const sp<IComposerCallback>& callback)
+Return<void> ComposerClient::registerCallback(
+        const sp<IComposerCallback>& callback)
 {
     // no locking as we require this function to be called only once
     mCallback = callback;
@@ -299,13 +305,13 @@
     return Void();
 }
 
-Return<uint32_t> HwcClient::getMaxVirtualDisplayCount()
+Return<uint32_t> ComposerClient::getMaxVirtualDisplayCount()
 {
     return mHal.getMaxVirtualDisplayCount();
 }
 
-Return<void> HwcClient::createVirtualDisplay(uint32_t width, uint32_t height,
-        PixelFormat formatHint, uint32_t outputBufferSlotCount,
+Return<void> ComposerClient::createVirtualDisplay(uint32_t width,
+        uint32_t height, PixelFormat formatHint, uint32_t outputBufferSlotCount,
         createVirtualDisplay_cb hidl_cb)
 {
     Display display = 0;
@@ -322,7 +328,7 @@
     return Void();
 }
 
-Return<Error> HwcClient::destroyVirtualDisplay(Display display)
+Return<Error> ComposerClient::destroyVirtualDisplay(Display display)
 {
     Error err = mHal.destroyVirtualDisplay(display);
     if (err == Error::NONE) {
@@ -334,8 +340,8 @@
     return err;
 }
 
-Return<void> HwcClient::createLayer(Display display, uint32_t bufferSlotCount,
-        createLayer_cb hidl_cb)
+Return<void> ComposerClient::createLayer(Display display,
+        uint32_t bufferSlotCount, createLayer_cb hidl_cb)
 {
     Layer layer = 0;
     Error err = mHal.createLayer(display, &layer);
@@ -351,7 +357,7 @@
     return Void();
 }
 
-Return<Error> HwcClient::destroyLayer(Display display, Layer layer)
+Return<Error> ComposerClient::destroyLayer(Display display, Layer layer)
 {
     Error err = mHal.destroyLayer(display, layer);
     if (err == Error::NONE) {
@@ -364,7 +370,7 @@
     return err;
 }
 
-Return<void> HwcClient::getActiveConfig(Display display,
+Return<void> ComposerClient::getActiveConfig(Display display,
         getActiveConfig_cb hidl_cb)
 {
     Config config = 0;
@@ -374,7 +380,7 @@
     return Void();
 }
 
-Return<Error> HwcClient::getClientTargetSupport(Display display,
+Return<Error> ComposerClient::getClientTargetSupport(Display display,
         uint32_t width, uint32_t height,
         PixelFormat format, Dataspace dataspace)
 {
@@ -383,7 +389,8 @@
     return err;
 }
 
-Return<void> HwcClient::getColorModes(Display display, getColorModes_cb hidl_cb)
+Return<void> ComposerClient::getColorModes(Display display,
+          getColorModes_cb hidl_cb)
 {
     hidl_vec<ColorMode> modes;
     Error err = mHal.getColorModes(display, &modes);
@@ -392,7 +399,7 @@
     return Void();
 }
 
-Return<void> HwcClient::getDisplayAttribute(Display display,
+Return<void> ComposerClient::getDisplayAttribute(Display display,
         Config config, Attribute attribute,
         getDisplayAttribute_cb hidl_cb)
 {
@@ -403,7 +410,7 @@
     return Void();
 }
 
-Return<void> HwcClient::getDisplayConfigs(Display display,
+Return<void> ComposerClient::getDisplayConfigs(Display display,
         getDisplayConfigs_cb hidl_cb)
 {
     hidl_vec<Config> configs;
@@ -413,7 +420,7 @@
     return Void();
 }
 
-Return<void> HwcClient::getDisplayName(Display display,
+Return<void> ComposerClient::getDisplayName(Display display,
         getDisplayName_cb hidl_cb)
 {
     hidl_string name;
@@ -423,7 +430,7 @@
     return Void();
 }
 
-Return<void> HwcClient::getDisplayType(Display display,
+Return<void> ComposerClient::getDisplayType(Display display,
         getDisplayType_cb hidl_cb)
 {
     DisplayType type = DisplayType::INVALID;
@@ -433,7 +440,7 @@
     return Void();
 }
 
-Return<void> HwcClient::getDozeSupport(Display display,
+Return<void> ComposerClient::getDozeSupport(Display display,
         getDozeSupport_cb hidl_cb)
 {
     bool support = false;
@@ -443,7 +450,7 @@
     return Void();
 }
 
-Return<void> HwcClient::getHdrCapabilities(Display display,
+Return<void> ComposerClient::getHdrCapabilities(Display display,
         getHdrCapabilities_cb hidl_cb)
 {
     hidl_vec<Hdr> types;
@@ -457,7 +464,7 @@
     return Void();
 }
 
-Return<Error> HwcClient::setClientTargetSlotCount(Display display,
+Return<Error> ComposerClient::setClientTargetSlotCount(Display display,
         uint32_t clientTargetSlotCount)
 {
     std::lock_guard<std::mutex> lock(mDisplayDataMutex);
@@ -472,39 +479,39 @@
     return Error::NONE;
 }
 
-Return<Error> HwcClient::setActiveConfig(Display display, Config config)
+Return<Error> ComposerClient::setActiveConfig(Display display, Config config)
 {
     Error err = mHal.setActiveConfig(display, config);
     return err;
 }
 
-Return<Error> HwcClient::setColorMode(Display display, ColorMode mode)
+Return<Error> ComposerClient::setColorMode(Display display, ColorMode mode)
 {
     Error err = mHal.setColorMode(display, mode);
     return err;
 }
 
-Return<Error> HwcClient::setPowerMode(Display display, PowerMode mode)
+Return<Error> ComposerClient::setPowerMode(Display display, PowerMode mode)
 {
     Error err = mHal.setPowerMode(display, mode);
     return err;
 }
 
-Return<Error> HwcClient::setVsyncEnabled(Display display, Vsync enabled)
+Return<Error> ComposerClient::setVsyncEnabled(Display display, Vsync enabled)
 {
     Error err = mHal.setVsyncEnabled(display, enabled);
     return err;
 }
 
-Return<Error> HwcClient::setInputCommandQueue(
+Return<Error> ComposerClient::setInputCommandQueue(
         const MQDescriptorSync<uint32_t>& descriptor)
 {
     std::lock_guard<std::mutex> lock(mCommandMutex);
-    return mReader.setMQDescriptor(descriptor) ?
+    return mReader->setMQDescriptor(descriptor) ?
         Error::NONE : Error::NO_RESOURCES;
 }
 
-Return<void> HwcClient::getOutputCommandQueue(
+Return<void> ComposerClient::getOutputCommandQueue(
         getOutputCommandQueue_cb hidl_cb)
 {
     // no locking as we require this function to be called inside
@@ -520,7 +527,7 @@
     return Void();
 }
 
-Return<void> HwcClient::executeCommands(uint32_t inLength,
+Return<void> ComposerClient::executeCommands(uint32_t inLength,
         const hidl_vec<hidl_handle>& inHandles,
         executeCommands_cb hidl_cb)
 {
@@ -530,12 +537,12 @@
     uint32_t outLength = 0;
     hidl_vec<hidl_handle> outHandles;
 
-    if (!mReader.readQueue(inLength, inHandles)) {
+    if (!mReader->readQueue(inLength, inHandles)) {
         hidl_cb(Error::BAD_PARAMETER, outChanged, outLength, outHandles);
         return Void();
     }
 
-    Error err = mReader.parse();
+    Error err = mReader->parse();
     if (err == Error::NONE &&
             !mWriter.writeQueue(&outChanged, &outLength, &outHandles)) {
         err = Error::NO_RESOURCES;
@@ -543,18 +550,29 @@
 
     hidl_cb(err, outChanged, outLength, outHandles);
 
-    mReader.reset();
+    mReader->reset();
     mWriter.reset();
 
     return Void();
 }
 
-HwcClient::CommandReader::CommandReader(HwcClient& client)
+std::unique_ptr<ComposerClient::CommandReader>
+ComposerClient::createCommandReader()
+{
+    return std::unique_ptr<ComposerClient::CommandReader>(
+        new CommandReader(*this));
+}
+
+ComposerClient::CommandReader::CommandReader(ComposerClient& client)
     : mClient(client), mHal(client.mHal), mWriter(client.mWriter)
 {
 }
 
-Error HwcClient::CommandReader::parse()
+ComposerClient::CommandReader::~CommandReader()
+{
+}
+
+Error ComposerClient::CommandReader::parse()
 {
     IComposerClient::Command command;
     uint16_t length = 0;
@@ -564,79 +582,7 @@
             break;
         }
 
-        bool parsed = false;
-        switch (command) {
-        case IComposerClient::Command::SELECT_DISPLAY:
-            parsed = parseSelectDisplay(length);
-            break;
-        case IComposerClient::Command::SELECT_LAYER:
-            parsed = parseSelectLayer(length);
-            break;
-        case IComposerClient::Command::SET_COLOR_TRANSFORM:
-            parsed = parseSetColorTransform(length);
-            break;
-        case IComposerClient::Command::SET_CLIENT_TARGET:
-            parsed = parseSetClientTarget(length);
-            break;
-        case IComposerClient::Command::SET_OUTPUT_BUFFER:
-            parsed = parseSetOutputBuffer(length);
-            break;
-        case IComposerClient::Command::VALIDATE_DISPLAY:
-            parsed = parseValidateDisplay(length);
-            break;
-        case IComposerClient::Command::ACCEPT_DISPLAY_CHANGES:
-            parsed = parseAcceptDisplayChanges(length);
-            break;
-        case IComposerClient::Command::PRESENT_DISPLAY:
-            parsed = parsePresentDisplay(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_CURSOR_POSITION:
-            parsed = parseSetLayerCursorPosition(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_BUFFER:
-            parsed = parseSetLayerBuffer(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_SURFACE_DAMAGE:
-            parsed = parseSetLayerSurfaceDamage(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_BLEND_MODE:
-            parsed = parseSetLayerBlendMode(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_COLOR:
-            parsed = parseSetLayerColor(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_COMPOSITION_TYPE:
-            parsed = parseSetLayerCompositionType(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_DATASPACE:
-            parsed = parseSetLayerDataspace(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_DISPLAY_FRAME:
-            parsed = parseSetLayerDisplayFrame(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_PLANE_ALPHA:
-            parsed = parseSetLayerPlaneAlpha(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_SIDEBAND_STREAM:
-            parsed = parseSetLayerSidebandStream(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_SOURCE_CROP:
-            parsed = parseSetLayerSourceCrop(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_TRANSFORM:
-            parsed = parseSetLayerTransform(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_VISIBLE_REGION:
-            parsed = parseSetLayerVisibleRegion(length);
-            break;
-        case IComposerClient::Command::SET_LAYER_Z_ORDER:
-            parsed = parseSetLayerZOrder(length);
-            break;
-        default:
-            parsed = false;
-            break;
-        }
-
+        bool parsed = parseCommand(command, length);
         endCommand();
 
         if (!parsed) {
@@ -649,7 +595,59 @@
     return (isEmpty()) ? Error::NONE : Error::BAD_PARAMETER;
 }
 
-bool HwcClient::CommandReader::parseSelectDisplay(uint16_t length)
+bool ComposerClient::CommandReader::parseCommand(
+        IComposerClient::Command command, uint16_t length) {
+    switch (command) {
+    case IComposerClient::Command::SELECT_DISPLAY:
+        return parseSelectDisplay(length);
+    case IComposerClient::Command::SELECT_LAYER:
+        return parseSelectLayer(length);
+    case IComposerClient::Command::SET_COLOR_TRANSFORM:
+        return parseSetColorTransform(length);
+    case IComposerClient::Command::SET_CLIENT_TARGET:
+        return parseSetClientTarget(length);
+    case IComposerClient::Command::SET_OUTPUT_BUFFER:
+        return parseSetOutputBuffer(length);
+    case IComposerClient::Command::VALIDATE_DISPLAY:
+        return parseValidateDisplay(length);
+    case IComposerClient::Command::ACCEPT_DISPLAY_CHANGES:
+        return parseAcceptDisplayChanges(length);
+    case IComposerClient::Command::PRESENT_DISPLAY:
+        return parsePresentDisplay(length);
+    case IComposerClient::Command::SET_LAYER_CURSOR_POSITION:
+        return parseSetLayerCursorPosition(length);
+    case IComposerClient::Command::SET_LAYER_BUFFER:
+        return parseSetLayerBuffer(length);
+    case IComposerClient::Command::SET_LAYER_SURFACE_DAMAGE:
+        return parseSetLayerSurfaceDamage(length);
+    case IComposerClient::Command::SET_LAYER_BLEND_MODE:
+        return parseSetLayerBlendMode(length);
+    case IComposerClient::Command::SET_LAYER_COLOR:
+        return parseSetLayerColor(length);
+    case IComposerClient::Command::SET_LAYER_COMPOSITION_TYPE:
+        return parseSetLayerCompositionType(length);
+    case IComposerClient::Command::SET_LAYER_DATASPACE:
+        return parseSetLayerDataspace(length);
+    case IComposerClient::Command::SET_LAYER_DISPLAY_FRAME:
+        return parseSetLayerDisplayFrame(length);
+    case IComposerClient::Command::SET_LAYER_PLANE_ALPHA:
+        return parseSetLayerPlaneAlpha(length);
+    case IComposerClient::Command::SET_LAYER_SIDEBAND_STREAM:
+        return parseSetLayerSidebandStream(length);
+    case IComposerClient::Command::SET_LAYER_SOURCE_CROP:
+        return parseSetLayerSourceCrop(length);
+    case IComposerClient::Command::SET_LAYER_TRANSFORM:
+        return parseSetLayerTransform(length);
+    case IComposerClient::Command::SET_LAYER_VISIBLE_REGION:
+        return parseSetLayerVisibleRegion(length);
+    case IComposerClient::Command::SET_LAYER_Z_ORDER:
+        return parseSetLayerZOrder(length);
+    default:
+        return false;
+    }
+}
+
+bool ComposerClient::CommandReader::parseSelectDisplay(uint16_t length)
 {
     if (length != CommandWriterBase::kSelectDisplayLength) {
         return false;
@@ -661,7 +659,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSelectLayer(uint16_t length)
+bool ComposerClient::CommandReader::parseSelectLayer(uint16_t length)
 {
     if (length != CommandWriterBase::kSelectLayerLength) {
         return false;
@@ -672,7 +670,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetColorTransform(uint16_t length)
+bool ComposerClient::CommandReader::parseSetColorTransform(uint16_t length)
 {
     if (length != CommandWriterBase::kSetColorTransformLength) {
         return false;
@@ -692,7 +690,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetClientTarget(uint16_t length)
+bool ComposerClient::CommandReader::parseSetClientTarget(uint16_t length)
 {
     // 4 parameters followed by N rectangles
     if ((length - 4) % 4 != 0) {
@@ -720,7 +718,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetOutputBuffer(uint16_t length)
+bool ComposerClient::CommandReader::parseSetOutputBuffer(uint16_t length)
 {
     if (length != CommandWriterBase::kSetOutputBufferLength) {
         return false;
@@ -744,7 +742,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseValidateDisplay(uint16_t length)
+bool ComposerClient::CommandReader::parseValidateDisplay(uint16_t length)
 {
     if (length != CommandWriterBase::kValidateDisplayLength) {
         return false;
@@ -771,7 +769,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseAcceptDisplayChanges(uint16_t length)
+bool ComposerClient::CommandReader::parseAcceptDisplayChanges(uint16_t length)
 {
     if (length != CommandWriterBase::kAcceptDisplayChangesLength) {
         return false;
@@ -785,7 +783,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parsePresentDisplay(uint16_t length)
+bool ComposerClient::CommandReader::parsePresentDisplay(uint16_t length)
 {
     if (length != CommandWriterBase::kPresentDisplayLength) {
         return false;
@@ -805,7 +803,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerCursorPosition(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerCursorPosition(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerCursorPositionLength) {
         return false;
@@ -820,7 +818,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerBuffer(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerBuffer(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerBufferLength) {
         return false;
@@ -844,7 +842,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerSurfaceDamage(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerSurfaceDamage(uint16_t length)
 {
     // N rectangles
     if (length % 4 != 0) {
@@ -860,7 +858,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerBlendMode(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerBlendMode(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerBlendModeLength) {
         return false;
@@ -874,7 +872,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerColor(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerColor(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerColorLength) {
         return false;
@@ -888,7 +886,8 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerCompositionType(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerCompositionType(
+        uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerCompositionTypeLength) {
         return false;
@@ -902,7 +901,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerDataspace(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerDataspace(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerDataspaceLength) {
         return false;
@@ -916,7 +915,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerDisplayFrame(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerDisplayFrame(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerDisplayFrameLength) {
         return false;
@@ -930,7 +929,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerPlaneAlpha(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerPlaneAlpha(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerPlaneAlphaLength) {
         return false;
@@ -944,7 +943,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerSidebandStream(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerSidebandStream(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerSidebandStreamLength) {
         return false;
@@ -963,7 +962,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerSourceCrop(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerSourceCrop(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerSourceCropLength) {
         return false;
@@ -977,7 +976,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerTransform(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerTransform(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerTransformLength) {
         return false;
@@ -991,7 +990,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerVisibleRegion(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerVisibleRegion(uint16_t length)
 {
     // N rectangles
     if (length % 4 != 0) {
@@ -1007,7 +1006,7 @@
     return true;
 }
 
-bool HwcClient::CommandReader::parseSetLayerZOrder(uint16_t length)
+bool ComposerClient::CommandReader::parseSetLayerZOrder(uint16_t length)
 {
     if (length != CommandWriterBase::kSetLayerZOrderLength) {
         return false;
@@ -1021,7 +1020,7 @@
     return true;
 }
 
-hwc_rect_t HwcClient::CommandReader::readRect()
+hwc_rect_t ComposerClient::CommandReader::readRect()
 {
     return hwc_rect_t{
         readSigned(),
@@ -1031,7 +1030,7 @@
     };
 }
 
-std::vector<hwc_rect_t> HwcClient::CommandReader::readRegion(size_t count)
+std::vector<hwc_rect_t> ComposerClient::CommandReader::readRegion(size_t count)
 {
     std::vector<hwc_rect_t> region;
     region.reserve(count);
@@ -1043,7 +1042,7 @@
     return region;
 }
 
-hwc_frect_t HwcClient::CommandReader::readFRect()
+hwc_frect_t ComposerClient::CommandReader::readFRect()
 {
     return hwc_frect_t{
         readFloat(),
@@ -1053,8 +1052,8 @@
     };
 }
 
-Error HwcClient::CommandReader::lookupBuffer(BufferCache cache, uint32_t slot,
-        bool useCache, buffer_handle_t& handle)
+Error ComposerClient::CommandReader::lookupBuffer(BufferCache cache,
+        uint32_t slot, bool useCache, buffer_handle_t& handle)
 {
     std::lock_guard<std::mutex> lock(mClient.mDisplayDataMutex);
 
diff --git a/graphics/composer/2.1/default/HwcClient.h b/graphics/composer/2.1/default/ComposerClient.h
similarity index 89%
rename from graphics/composer/2.1/default/HwcClient.h
rename to graphics/composer/2.1/default/ComposerClient.h
index 35a0450..d351cfb 100644
--- a/graphics/composer/2.1/default/HwcClient.h
+++ b/graphics/composer/2.1/default/ComposerClient.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_HWC_CLIENT_H
-#define ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_HWC_CLIENT_H
+#ifndef ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_COMPOSER_CLIENT_H
+#define ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_COMPOSER_CLIENT_H
 
 #include <mutex>
 #include <unordered_map>
@@ -50,10 +50,12 @@
     buffer_handle_t mHandle;
 };
 
-class HwcClient : public IComposerClient {
+class ComposerClient : public IComposerClient {
 public:
-    HwcClient(HwcHal& hal);
-    virtual ~HwcClient();
+    ComposerClient(ComposerBase& hal);
+    virtual ~ComposerClient();
+
+    void initialize();
 
     void onHotplug(Display display, IComposerCallback::Connection connected);
     void onRefresh(Display display);
@@ -104,7 +106,7 @@
             const hidl_vec<hidl_handle>& inHandles,
             executeCommands_cb hidl_cb) override;
 
-private:
+protected:
     struct LayerBuffers {
         std::vector<BufferClone> Buffers;
         BufferClone SidebandStream;
@@ -123,10 +125,15 @@
 
     class CommandReader : public CommandReaderBase {
     public:
-        CommandReader(HwcClient& client);
+        CommandReader(ComposerClient& client);
+        virtual ~CommandReader();
+
         Error parse();
 
-    private:
+    protected:
+        virtual bool parseCommand(IComposerClient::Command command,
+                uint16_t length);
+
         bool parseSelectDisplay(uint16_t length);
         bool parseSelectLayer(uint16_t length);
         bool parseSetColorTransform(uint16_t length);
@@ -169,21 +176,23 @@
                     0, false, handle);
         }
 
-        HwcClient& mClient;
-        HwcHal& mHal;
+        ComposerClient& mClient;
+        ComposerBase& mHal;
         CommandWriterBase& mWriter;
 
         Display mDisplay;
         Layer mLayer;
     };
 
-    HwcHal& mHal;
+    virtual std::unique_ptr<CommandReader> createCommandReader();
+
+    ComposerBase& mHal;
 
     // 64KiB minus a small space for metadata such as read/write pointers
     static constexpr size_t kWriterInitialSize =
         64 * 1024 / sizeof(uint32_t) - 16;
     std::mutex mCommandMutex;
-    CommandReader mReader;
+    std::unique_ptr<CommandReader> mReader;
     CommandWriterBase mWriter;
 
     sp<IComposerCallback> mCallback;
@@ -199,4 +208,4 @@
 } // namespace hardware
 } // namespace android
 
-#endif  // ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_HWC_CLIENT_H
+#endif  // ANDROID_HARDWARE_GRAPHICS_COMPOSER_V2_1_COMPOSER_CLIENT_H
diff --git a/graphics/composer/2.1/default/Hwc.cpp b/graphics/composer/2.1/default/Hwc.cpp
index 4efb12b..cf82967 100644
--- a/graphics/composer/2.1/default/Hwc.cpp
+++ b/graphics/composer/2.1/default/Hwc.cpp
@@ -20,8 +20,8 @@
 
 #include <log/log.h>
 
+#include "ComposerClient.h"
 #include "Hwc.h"
-#include "HwcClient.h"
 
 namespace android {
 namespace hardware {
@@ -184,14 +184,15 @@
 Return<void> HwcHal::createClient(createClient_cb hidl_cb)
 {
     Error err = Error::NONE;
-    sp<HwcClient> client;
+    sp<ComposerClient> client;
 
     {
         std::lock_guard<std::mutex> lock(mClientMutex);
 
         // only one client is allowed
         if (mClient == nullptr) {
-            client = new HwcClient(*this);
+            client = new ComposerClient(*this);
+            client->initialize();
             mClient = client;
         } else {
             err = Error::NO_RESOURCES;
@@ -203,7 +204,7 @@
     return Void();
 }
 
-sp<HwcClient> HwcHal::getClient()
+sp<ComposerClient> HwcHal::getClient()
 {
     std::lock_guard<std::mutex> lock(mClientMutex);
     return (mClient != nullptr) ? mClient.promote() : nullptr;
diff --git a/graphics/composer/2.1/default/Hwc.h b/graphics/composer/2.1/default/Hwc.h
index 6420b31..ca08cf0 100644
--- a/graphics/composer/2.1/default/Hwc.h
+++ b/graphics/composer/2.1/default/Hwc.h
@@ -24,6 +24,8 @@
 #include <android/hardware/graphics/composer/2.1/IComposer.h>
 #include <hardware/hwcomposer2.h>
 
+#include "ComposerBase.h"
+
 namespace android {
 namespace hardware {
 namespace graphics {
@@ -38,96 +40,101 @@
 using android::hardware::graphics::common::V1_0::ColorTransform;
 using android::hardware::graphics::common::V1_0::Hdr;
 
-class HwcClient;
+class ComposerClient;
 
-class HwcHal : public IComposer {
+class HwcHal : public IComposer, public ComposerBase {
 public:
     HwcHal(const hw_module_t* module);
     virtual ~HwcHal();
 
+    bool hasCapability(Capability capability) const;
+
     // IComposer interface
     Return<void> getCapabilities(getCapabilities_cb hidl_cb) override;
     Return<void> dumpDebugInfo(dumpDebugInfo_cb hidl_cb) override;
     Return<void> createClient(createClient_cb hidl_cb) override;
 
-    bool hasCapability(Capability capability) const;
-
-    void removeClient();
-
-    void enableCallback(bool enable);
-
-    uint32_t getMaxVirtualDisplayCount();
+    // ComposerBase interface
+    void removeClient() override;
+    void enableCallback(bool enable) override;
+    uint32_t getMaxVirtualDisplayCount() override;
     Error createVirtualDisplay(uint32_t width, uint32_t height,
-        PixelFormat* format, Display* outDisplay);
-    Error destroyVirtualDisplay(Display display);
+        PixelFormat* format, Display* outDisplay) override;
+    Error destroyVirtualDisplay(Display display) override;
 
-    Error createLayer(Display display, Layer* outLayer);
-    Error destroyLayer(Display display, Layer layer);
+    Error createLayer(Display display, Layer* outLayer) override;
+    Error destroyLayer(Display display, Layer layer) override;
 
-    Error getActiveConfig(Display display, Config* outConfig);
+    Error getActiveConfig(Display display, Config* outConfig) override;
     Error getClientTargetSupport(Display display,
             uint32_t width, uint32_t height,
-            PixelFormat format, Dataspace dataspace);
-    Error getColorModes(Display display, hidl_vec<ColorMode>* outModes);
+            PixelFormat format, Dataspace dataspace) override;
+    Error getColorModes(Display display,
+            hidl_vec<ColorMode>* outModes) override;
     Error getDisplayAttribute(Display display, Config config,
-            IComposerClient::Attribute attribute, int32_t* outValue);
-    Error getDisplayConfigs(Display display, hidl_vec<Config>* outConfigs);
-    Error getDisplayName(Display display, hidl_string* outName);
+            IComposerClient::Attribute attribute, int32_t* outValue) override;
+    Error getDisplayConfigs(Display display,
+            hidl_vec<Config>* outConfigs) override;
+    Error getDisplayName(Display display, hidl_string* outName) override;
     Error getDisplayType(Display display,
-            IComposerClient::DisplayType* outType);
-    Error getDozeSupport(Display display, bool* outSupport);
+            IComposerClient::DisplayType* outType) override;
+    Error getDozeSupport(Display display, bool* outSupport) override;
     Error getHdrCapabilities(Display display, hidl_vec<Hdr>* outTypes,
             float* outMaxLuminance, float* outMaxAverageLuminance,
-            float* outMinLuminance);
+            float* outMinLuminance) override;
 
-    Error setActiveConfig(Display display, Config config);
-    Error setColorMode(Display display, ColorMode mode);
-    Error setPowerMode(Display display, IComposerClient::PowerMode mode);
-    Error setVsyncEnabled(Display display, IComposerClient::Vsync enabled);
+    Error setActiveConfig(Display display, Config config) override;
+    Error setColorMode(Display display, ColorMode mode) override;
+    Error setPowerMode(Display display,
+            IComposerClient::PowerMode mode) override;
+    Error setVsyncEnabled(Display display,
+            IComposerClient::Vsync enabled) override;
 
     Error setColorTransform(Display display, const float* matrix,
-            int32_t hint);
+            int32_t hint) override;
     Error setClientTarget(Display display, buffer_handle_t target,
             int32_t acquireFence, int32_t dataspace,
-            const std::vector<hwc_rect_t>& damage);
+            const std::vector<hwc_rect_t>& damage) override;
     Error setOutputBuffer(Display display, buffer_handle_t buffer,
-            int32_t releaseFence);
+            int32_t releaseFence) override;
     Error validateDisplay(Display display,
             std::vector<Layer>* outChangedLayers,
             std::vector<IComposerClient::Composition>* outCompositionTypes,
             uint32_t* outDisplayRequestMask,
             std::vector<Layer>* outRequestedLayers,
-            std::vector<uint32_t>* outRequestMasks);
-    Error acceptDisplayChanges(Display display);
+            std::vector<uint32_t>* outRequestMasks) override;
+    Error acceptDisplayChanges(Display display) override;
     Error presentDisplay(Display display, int32_t* outPresentFence,
             std::vector<Layer>* outLayers,
-            std::vector<int32_t>* outReleaseFences);
+            std::vector<int32_t>* outReleaseFences) override;
 
     Error setLayerCursorPosition(Display display, Layer layer,
-            int32_t x, int32_t y);
+            int32_t x, int32_t y) override;
     Error setLayerBuffer(Display display, Layer layer,
-            buffer_handle_t buffer, int32_t acquireFence);
+            buffer_handle_t buffer, int32_t acquireFence) override;
     Error setLayerSurfaceDamage(Display display, Layer layer,
-            const std::vector<hwc_rect_t>& damage);
-    Error setLayerBlendMode(Display display, Layer layer, int32_t mode);
+            const std::vector<hwc_rect_t>& damage) override;
+    Error setLayerBlendMode(Display display, Layer layer,
+            int32_t mode) override;
     Error setLayerColor(Display display, Layer layer,
-            IComposerClient::Color color);
+            IComposerClient::Color color) override;
     Error setLayerCompositionType(Display display, Layer layer,
-            int32_t type);
+            int32_t type) override;
     Error setLayerDataspace(Display display, Layer layer,
-            int32_t dataspace);
+            int32_t dataspace) override;
     Error setLayerDisplayFrame(Display display, Layer layer,
-            const hwc_rect_t& frame);
-    Error setLayerPlaneAlpha(Display display, Layer layer, float alpha);
+            const hwc_rect_t& frame) override;
+    Error setLayerPlaneAlpha(Display display, Layer layer,
+            float alpha) override;
     Error setLayerSidebandStream(Display display, Layer layer,
-            buffer_handle_t stream);
+            buffer_handle_t stream) override;
     Error setLayerSourceCrop(Display display, Layer layer,
-            const hwc_frect_t& crop);
+            const hwc_frect_t& crop) override;
     Error setLayerTransform(Display display, Layer layer,
-            int32_t transform);
+            int32_t transform) override;
     Error setLayerVisibleRegion(Display display, Layer layer,
-            const std::vector<hwc_rect_t>& visible);
-    Error setLayerZOrder(Display display, Layer layer, uint32_t z);
+            const std::vector<hwc_rect_t>& visible) override;
+    Error setLayerZOrder(Display display, Layer layer, uint32_t z) override;
 
 private:
     void initCapabilities();
@@ -136,7 +143,7 @@
     void initDispatch(hwc2_function_descriptor_t desc, T* outPfn);
     void initDispatch();
 
-    sp<HwcClient> getClient();
+    sp<ComposerClient> getClient();
 
     static void hotplugHook(hwc2_callback_data_t callbackData,
         hwc2_display_t display, int32_t connected);
@@ -196,7 +203,7 @@
     } mDispatch;
 
     std::mutex mClientMutex;
-    wp<HwcClient> mClient;
+    wp<ComposerClient> mClient;
 };
 
 extern "C" IComposer* HIDL_FETCH_IComposer(const char* name);