v8/renderscript/RenderScript.java

/*
 * Copyright (C) 2012 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.
 */

package android.support.v8.renderscript;

import java.io.File;
import java.lang.reflect.Field;

import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.res.AssetManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Process;
import android.util.Log;
import android.view.Surface;


/**
 * Renderscript base master class.  An instance of this class creates native
 * worker threads for processing commands from this object.  This base class
 * does not provide any extended capabilities beyond simple data processing.
 * For extended capabilities use derived classes such as RenderScriptGL.
 *
 * <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>For more information about creating an application that uses Renderscript, read the
 * <a href="{@docRoot}guide/topics/graphics/renderscript.html">Renderscript</a> developer guide.</p>
 * </div>
 **/
public class RenderScript {
    static final String LOG_TAG = "RenderScript_jni";
    static final boolean DEBUG  = false;
    @SuppressWarnings({"UnusedDeclaration", "deprecation"})
    static final boolean LOG_ENABLED = false;

    private Context mApplicationContext;
    boolean mUseNativeRS;

    static class NRS {
        android.renderscript.RenderScript mRS;

        android.renderscript.RenderScript getRS() {
            return mRS;
        }
    }
    NRS mNRS;

    /*
     * We use a class initializer to allow the native code to cache some
     * field offsets.
     */
    @SuppressWarnings({"FieldCanBeLocal", "UnusedDeclaration"})
    static boolean sInitialized;
    native static void _nInit();


    static {
        sInitialized = false;
        try {
            System.loadLibrary("rsjni");
            _nInit();
            sInitialized = true;
        } catch (UnsatisfiedLinkError e) {
            Log.e(LOG_TAG, "Error loading RS jni library: " + e);
            throw new RSRuntimeException("Error loading RS jni library: " + e);
        }
    }

    // Non-threadsafe functions.
    native int  nDeviceCreate();
    native void nDeviceDestroy(int dev);
    native void nDeviceSetConfig(int dev, int param, int value);
    native int nContextGetUserMessage(int con, int[] data);
    native String nContextGetErrorMessage(int con);
    native int  nContextPeekMessage(int con, int[] subID);
    native void nContextInitToClient(int con);
    native void nContextDeinitToClient(int con);

    /**
     * Name of the file that holds the object cache.
     */
    private static final String CACHE_PATH = "com.android.renderscript.cache";
    static String mCachePath;

     /**
     * Sets the directory to use as a persistent storage for the
     * renderscript object file cache.
     *
     * @hide
     * @param cacheDir A directory the current process can write to
     */
    public static void setupDiskCache(File cacheDir) {
        File f = new File(cacheDir, CACHE_PATH);
        mCachePath = f.getAbsolutePath();
        f.mkdirs();
    }


    // Methods below are wrapped to protect the non-threadsafe
    // lockless fifo.
    native int  rsnContextCreate(int dev, int ver, int sdkVer);
    synchronized int nContextCreate(int dev, int ver, int sdkVer) {
        return rsnContextCreate(dev, ver, sdkVer);
    }
    native void rsnContextDestroy(int con);
    synchronized void nContextDestroy() {
        validate();
        rsnContextDestroy(mContext);
    }
    native void rsnContextSetPriority(int con, int p);
    synchronized void nContextSetPriority(int p) {
        validate();
        rsnContextSetPriority(mContext, p);
    }
    native void rsnContextDump(int con, int bits);
    synchronized void nContextDump(int bits) {
        validate();
        rsnContextDump(mContext, bits);
    }
    native void rsnContextFinish(int con);
    synchronized void nContextFinish() {
        validate();
        rsnContextFinish(mContext);
    }

    native void rsnObjDestroy(int con, int id);
    synchronized void nObjDestroy(int id) {
        // There is a race condition here.  The calling code may be run
        // by the gc while teardown is occuring.  This protects againts
        // deleting dead objects.
        if (mContext != 0) {
            rsnObjDestroy(mContext, id);
        }
    }

    native int  rsnElementCreate(int con, int type, int kind, boolean norm, int vecSize);
    synchronized int nElementCreate(int type, int kind, boolean norm, int vecSize) {
        validate();
        return rsnElementCreate(mContext, type, kind, norm, vecSize);
    }
    native int  rsnElementCreate2(int con, int[] elements, String[] names, int[] arraySizes);
    synchronized int nElementCreate2(int[] elements, String[] names, int[] arraySizes) {
        validate();
        return rsnElementCreate2(mContext, elements, names, arraySizes);
    }
    native void rsnElementGetNativeData(int con, int id, int[] elementData);
    synchronized void nElementGetNativeData(int id, int[] elementData) {
        validate();
        rsnElementGetNativeData(mContext, id, elementData);
    }
    native void rsnElementGetSubElements(int con, int id,
                                         int[] IDs, String[] names, int[] arraySizes);
    synchronized void nElementGetSubElements(int id, int[] IDs, String[] names, int[] arraySizes) {
        validate();
        rsnElementGetSubElements(mContext, id, IDs, names, arraySizes);
    }

    native int rsnTypeCreate(int con, int eid, int x, int y, int z, boolean mips, boolean faces);
    synchronized int nTypeCreate(int eid, int x, int y, int z, boolean mips, boolean faces) {
        validate();
        return rsnTypeCreate(mContext, eid, x, y, z, mips, faces);
    }
    native void rsnTypeGetNativeData(int con, int id, int[] typeData);
    synchronized void nTypeGetNativeData(int id, int[] typeData) {
        validate();
        rsnTypeGetNativeData(mContext, id, typeData);
    }

    native int  rsnAllocationCreateTyped(int con, int type, int mip, int usage, int pointer);
    synchronized int nAllocationCreateTyped(int type, int mip, int usage, int pointer) {
        validate();
        return rsnAllocationCreateTyped(mContext, type, mip, usage, pointer);
    }
    native int  rsnAllocationCreateFromBitmap(int con, int type, int mip, Bitmap bmp, int usage);
    synchronized int nAllocationCreateFromBitmap(int type, int mip, Bitmap bmp, int usage) {
        validate();
        return rsnAllocationCreateFromBitmap(mContext, type, mip, bmp, usage);
    }
    native int  rsnAllocationCubeCreateFromBitmap(int con, int type, int mip, Bitmap bmp, int usage);
    synchronized int nAllocationCubeCreateFromBitmap(int type, int mip, Bitmap bmp, int usage) {
        validate();
        return rsnAllocationCubeCreateFromBitmap(mContext, type, mip, bmp, usage);
    }
    native int  rsnAllocationCreateBitmapRef(int con, int type, Bitmap bmp);
    synchronized int nAllocationCreateBitmapRef(int type, Bitmap bmp) {
        validate();
        return rsnAllocationCreateBitmapRef(mContext, type, bmp);
    }
    native int  rsnAllocationCreateFromAssetStream(int con, int mips, int assetStream, int usage);
    synchronized int nAllocationCreateFromAssetStream(int mips, int assetStream, int usage) {
        validate();
        return rsnAllocationCreateFromAssetStream(mContext, mips, assetStream, usage);
    }

    native void  rsnAllocationCopyToBitmap(int con, int alloc, Bitmap bmp);
    synchronized void nAllocationCopyToBitmap(int alloc, Bitmap bmp) {
        validate();
        rsnAllocationCopyToBitmap(mContext, alloc, bmp);
    }


    native void rsnAllocationSyncAll(int con, int alloc, int src);
    synchronized void nAllocationSyncAll(int alloc, int src) {
        validate();
        rsnAllocationSyncAll(mContext, alloc, src);
    }


    native void rsnAllocationGenerateMipmaps(int con, int alloc);
    synchronized void nAllocationGenerateMipmaps(int alloc) {
        validate();
        rsnAllocationGenerateMipmaps(mContext, alloc);
    }
    native void  rsnAllocationCopyFromBitmap(int con, int alloc, Bitmap bmp);
    synchronized void nAllocationCopyFromBitmap(int alloc, Bitmap bmp) {
        validate();
        rsnAllocationCopyFromBitmap(mContext, alloc, bmp);
    }


    native void rsnAllocationData1D(int con, int id, int off, int mip, int count, int[] d, int sizeBytes);
    synchronized void nAllocationData1D(int id, int off, int mip, int count, int[] d, int sizeBytes) {
        validate();
        rsnAllocationData1D(mContext, id, off, mip, count, d, sizeBytes);
    }
    native void rsnAllocationData1D(int con, int id, int off, int mip, int count, short[] d, int sizeBytes);
    synchronized void nAllocationData1D(int id, int off, int mip, int count, short[] d, int sizeBytes) {
        validate();
        rsnAllocationData1D(mContext, id, off, mip, count, d, sizeBytes);
    }
    native void rsnAllocationData1D(int con, int id, int off, int mip, int count, byte[] d, int sizeBytes);
    synchronized void nAllocationData1D(int id, int off, int mip, int count, byte[] d, int sizeBytes) {
        validate();
        rsnAllocationData1D(mContext, id, off, mip, count, d, sizeBytes);
    }
    native void rsnAllocationData1D(int con, int id, int off, int mip, int count, float[] d, int sizeBytes);
    synchronized void nAllocationData1D(int id, int off, int mip, int count, float[] d, int sizeBytes) {
        validate();
        rsnAllocationData1D(mContext, id, off, mip, count, d, sizeBytes);
    }

    native void rsnAllocationElementData1D(int con, int id, int xoff, int mip, int compIdx, byte[] d, int sizeBytes);
    synchronized void nAllocationElementData1D(int id, int xoff, int mip, int compIdx, byte[] d, int sizeBytes) {
        validate();
        rsnAllocationElementData1D(mContext, id, xoff, mip, compIdx, d, sizeBytes);
    }

    native void rsnAllocationData2D(int con,
                                    int dstAlloc, int dstXoff, int dstYoff,
                                    int dstMip, int dstFace,
                                    int width, int height,
                                    int srcAlloc, int srcXoff, int srcYoff,
                                    int srcMip, int srcFace);
    synchronized void nAllocationData2D(int dstAlloc, int dstXoff, int dstYoff,
                                        int dstMip, int dstFace,
                                        int width, int height,
                                        int srcAlloc, int srcXoff, int srcYoff,
                                        int srcMip, int srcFace) {
        validate();
        rsnAllocationData2D(mContext,
                            dstAlloc, dstXoff, dstYoff,
                            dstMip, dstFace,
                            width, height,
                            srcAlloc, srcXoff, srcYoff,
                            srcMip, srcFace);
    }

    native void rsnAllocationData2D(int con, int id, int xoff, int yoff, int mip, int face, int w, int h, byte[] d, int sizeBytes);
    synchronized void nAllocationData2D(int id, int xoff, int yoff, int mip, int face, int w, int h, byte[] d, int sizeBytes) {
        validate();
        rsnAllocationData2D(mContext, id, xoff, yoff, mip, face, w, h, d, sizeBytes);
    }
    native void rsnAllocationData2D(int con, int id, int xoff, int yoff, int mip, int face, int w, int h, short[] d, int sizeBytes);
    synchronized void nAllocationData2D(int id, int xoff, int yoff, int mip, int face, int w, int h, short[] d, int sizeBytes) {
        validate();
        rsnAllocationData2D(mContext, id, xoff, yoff, mip, face, w, h, d, sizeBytes);
    }
    native void rsnAllocationData2D(int con, int id, int xoff, int yoff, int mip, int face, int w, int h, int[] d, int sizeBytes);
    synchronized void nAllocationData2D(int id, int xoff, int yoff, int mip, int face, int w, int h, int[] d, int sizeBytes) {
        validate();
        rsnAllocationData2D(mContext, id, xoff, yoff, mip, face, w, h, d, sizeBytes);
    }
    native void rsnAllocationData2D(int con, int id, int xoff, int yoff, int mip, int face, int w, int h, float[] d, int sizeBytes);
    synchronized void nAllocationData2D(int id, int xoff, int yoff, int mip, int face, int w, int h, float[] d, int sizeBytes) {
        validate();
        rsnAllocationData2D(mContext, id, xoff, yoff, mip, face, w, h, d, sizeBytes);
    }
    native void rsnAllocationData2D(int con, int id, int xoff, int yoff, int mip, int face, Bitmap b);
    synchronized void nAllocationData2D(int id, int xoff, int yoff, int mip, int face, Bitmap b) {
        validate();
        rsnAllocationData2D(mContext, id, xoff, yoff, mip, face, b);
    }

    native void rsnAllocationRead(int con, int id, byte[] d);
    synchronized void nAllocationRead(int id, byte[] d) {
        validate();
        rsnAllocationRead(mContext, id, d);
    }
    native void rsnAllocationRead(int con, int id, short[] d);
    synchronized void nAllocationRead(int id, short[] d) {
        validate();
        rsnAllocationRead(mContext, id, d);
    }
    native void rsnAllocationRead(int con, int id, int[] d);
    synchronized void nAllocationRead(int id, int[] d) {
        validate();
        rsnAllocationRead(mContext, id, d);
    }
    native void rsnAllocationRead(int con, int id, float[] d);
    synchronized void nAllocationRead(int id, float[] d) {
        validate();
        rsnAllocationRead(mContext, id, d);
    }
    native int  rsnAllocationGetType(int con, int id);
    synchronized int nAllocationGetType(int id) {
        validate();
        return rsnAllocationGetType(mContext, id);
    }

    native void rsnAllocationResize1D(int con, int id, int dimX);
    synchronized void nAllocationResize1D(int id, int dimX) {
        validate();
        rsnAllocationResize1D(mContext, id, dimX);
    }
    native void rsnAllocationResize2D(int con, int id, int dimX, int dimY);
    synchronized void nAllocationResize2D(int id, int dimX, int dimY) {
        validate();
        rsnAllocationResize2D(mContext, id, dimX, dimY);
    }

    native void rsnScriptBindAllocation(int con, int script, int alloc, int slot);
    synchronized void nScriptBindAllocation(int script, int alloc, int slot) {
        validate();
        rsnScriptBindAllocation(mContext, script, alloc, slot);
    }
    native void rsnScriptSetTimeZone(int con, int script, byte[] timeZone);
    synchronized void nScriptSetTimeZone(int script, byte[] timeZone) {
        validate();
        rsnScriptSetTimeZone(mContext, script, timeZone);
    }
    native void rsnScriptInvoke(int con, int id, int slot);
    synchronized void nScriptInvoke(int id, int slot) {
        validate();
        rsnScriptInvoke(mContext, id, slot);
    }
    native void rsnScriptForEach(int con, int id, int slot, int ain, int aout, byte[] params);
    native void rsnScriptForEach(int con, int id, int slot, int ain, int aout);
    synchronized void nScriptForEach(int id, int slot, int ain, int aout, byte[] params) {
        validate();
        if (params == null) {
            rsnScriptForEach(mContext, id, slot, ain, aout);
        } else {
            rsnScriptForEach(mContext, id, slot, ain, aout, params);
        }
    }
    native void rsnScriptInvokeV(int con, int id, int slot, byte[] params);
    synchronized void nScriptInvokeV(int id, int slot, byte[] params) {
        validate();
        rsnScriptInvokeV(mContext, id, slot, params);
    }
    native void rsnScriptSetVarI(int con, int id, int slot, int val);
    synchronized void nScriptSetVarI(int id, int slot, int val) {
        validate();
        rsnScriptSetVarI(mContext, id, slot, val);
    }
    native void rsnScriptSetVarJ(int con, int id, int slot, long val);
    synchronized void nScriptSetVarJ(int id, int slot, long val) {
        validate();
        rsnScriptSetVarJ(mContext, id, slot, val);
    }
    native void rsnScriptSetVarF(int con, int id, int slot, float val);
    synchronized void nScriptSetVarF(int id, int slot, float val) {
        validate();
        rsnScriptSetVarF(mContext, id, slot, val);
    }
    native void rsnScriptSetVarD(int con, int id, int slot, double val);
    synchronized void nScriptSetVarD(int id, int slot, double val) {
        validate();
        rsnScriptSetVarD(mContext, id, slot, val);
    }
    native void rsnScriptSetVarV(int con, int id, int slot, byte[] val);
    synchronized void nScriptSetVarV(int id, int slot, byte[] val) {
        validate();
        rsnScriptSetVarV(mContext, id, slot, val);
    }
    native void rsnScriptSetVarVE(int con, int id, int slot, byte[] val,
                                  int e, int[] dims);
    synchronized void nScriptSetVarVE(int id, int slot, byte[] val,
                                      int e, int[] dims) {
        validate();
        rsnScriptSetVarVE(mContext, id, slot, val, e, dims);
    }
    native void rsnScriptSetVarObj(int con, int id, int slot, int val);
    synchronized void nScriptSetVarObj(int id, int slot, int val) {
        validate();
        rsnScriptSetVarObj(mContext, id, slot, val);
    }

    native int  rsnScriptCCreate(int con, String resName, String cacheDir,
                                 byte[] script, int length);
    synchronized int nScriptCCreate(String resName, String cacheDir, byte[] script, int length) {
        validate();
        return rsnScriptCCreate(mContext, resName, cacheDir, script, length);
    }

    native int  rsnScriptIntrinsicCreate(int con, int id, int eid);
    synchronized int nScriptIntrinsicCreate(int id, int eid) {
        validate();
        return rsnScriptIntrinsicCreate(mContext, id, eid);
    }

    native int  rsnScriptKernelIDCreate(int con, int sid, int slot, int sig);
    synchronized int nScriptKernelIDCreate(int sid, int slot, int sig) {
        validate();
        return rsnScriptKernelIDCreate(mContext, sid, slot, sig);
    }

    native int  rsnScriptFieldIDCreate(int con, int sid, int slot);
    synchronized int nScriptFieldIDCreate(int sid, int slot) {
        validate();
        return rsnScriptFieldIDCreate(mContext, sid, slot);
    }

    native int  rsnScriptGroupCreate(int con, int[] kernels, int[] src, int[] dstk, int[] dstf, int[] types);
    synchronized int nScriptGroupCreate(int[] kernels, int[] src, int[] dstk, int[] dstf, int[] types) {
        validate();
        return rsnScriptGroupCreate(mContext, kernels, src, dstk, dstf, types);
    }

    native void rsnScriptGroupSetInput(int con, int group, int kernel, int alloc);
    synchronized void nScriptGroupSetInput(int group, int kernel, int alloc) {
        validate();
        rsnScriptGroupSetInput(mContext, group, kernel, alloc);
    }

    native void rsnScriptGroupSetOutput(int con, int group, int kernel, int alloc);
    synchronized void nScriptGroupSetOutput(int group, int kernel, int alloc) {
        validate();
        rsnScriptGroupSetOutput(mContext, group, kernel, alloc);
    }

    native void rsnScriptGroupExecute(int con, int group);
    synchronized void nScriptGroupExecute(int group) {
        validate();
        rsnScriptGroupExecute(mContext, group);
    }

    native int  rsnSamplerCreate(int con, int magFilter, int minFilter,
                                 int wrapS, int wrapT, int wrapR, float aniso);
    synchronized int nSamplerCreate(int magFilter, int minFilter,
                                 int wrapS, int wrapT, int wrapR, float aniso) {
        validate();
        return rsnSamplerCreate(mContext, magFilter, minFilter, wrapS, wrapT, wrapR, aniso);
    }


    int     mDev;
    int     mContext;
    @SuppressWarnings({"FieldCanBeLocal"})
    MessageThread mMessageThread;

    Element mElement_U8;
    Element mElement_I8;
    Element mElement_U16;
    Element mElement_I16;
    Element mElement_U32;
    Element mElement_I32;
    Element mElement_U64;
    Element mElement_I64;
    Element mElement_F32;
    Element mElement_F64;
    Element mElement_BOOLEAN;

    Element mElement_ELEMENT;
    Element mElement_TYPE;
    Element mElement_ALLOCATION;
    Element mElement_SAMPLER;
    Element mElement_SCRIPT;

    Element mElement_A_8;
    Element mElement_RGB_565;
    Element mElement_RGB_888;
    Element mElement_RGBA_5551;
    Element mElement_RGBA_4444;
    Element mElement_RGBA_8888;

    Element mElement_FLOAT_2;
    Element mElement_FLOAT_3;
    Element mElement_FLOAT_4;

    Element mElement_DOUBLE_2;
    Element mElement_DOUBLE_3;
    Element mElement_DOUBLE_4;

    Element mElement_UCHAR_2;
    Element mElement_UCHAR_3;
    Element mElement_UCHAR_4;

    Element mElement_CHAR_2;
    Element mElement_CHAR_3;
    Element mElement_CHAR_4;

    Element mElement_USHORT_2;
    Element mElement_USHORT_3;
    Element mElement_USHORT_4;

    Element mElement_SHORT_2;
    Element mElement_SHORT_3;
    Element mElement_SHORT_4;

    Element mElement_UINT_2;
    Element mElement_UINT_3;
    Element mElement_UINT_4;

    Element mElement_INT_2;
    Element mElement_INT_3;
    Element mElement_INT_4;

    Element mElement_ULONG_2;
    Element mElement_ULONG_3;
    Element mElement_ULONG_4;

    Element mElement_LONG_2;
    Element mElement_LONG_3;
    Element mElement_LONG_4;

    Element mElement_MATRIX_4X4;
    Element mElement_MATRIX_3X3;
    Element mElement_MATRIX_2X2;

    Sampler mSampler_CLAMP_NEAREST;
    Sampler mSampler_CLAMP_LINEAR;
    Sampler mSampler_CLAMP_LINEAR_MIP_LINEAR;
    Sampler mSampler_WRAP_NEAREST;
    Sampler mSampler_WRAP_LINEAR;
    Sampler mSampler_WRAP_LINEAR_MIP_LINEAR;

    ///////////////////////////////////////////////////////////////////////////////////
    //

    /**
     * Base class application should derive from for handling RS messages
     * coming from their scripts.  When a script calls sendToClient the data
     * fields will be filled in and then the run method called by a message
     * handling thread.  This will occur some time after sendToClient completes
     * in the script.
     *
     */
    public static class RSMessageHandler implements Runnable {
        protected int[] mData;
        protected int mID;
        protected int mLength;
        public void run() {
        }
    }
    /**
     * If an application is expecting messages it should set this field to an
     * instance of RSMessage.  This instance will receive all the user messages
     * sent from sendToClient by scripts from this context.
     *
     */
    RSMessageHandler mMessageCallback = null;

    public void setMessageHandler(RSMessageHandler msg) {
        mMessageCallback = msg;
    }
    public RSMessageHandler getMessageHandler() {
        return mMessageCallback;
    }

    /**
     * Runtime error base class.  An application should derive from this class
     * if it wishes to install an error handler.  When errors occur at runtime
     * the fields in this class will be filled and the run method called.
     *
     */
    public static class RSErrorHandler implements Runnable {
        protected String mErrorMessage;
        protected int mErrorNum;
        public void run() {
        }
    }

    /**
     * Application Error handler.  All runtime errors will be dispatched to the
     * instance of RSAsyncError set here.  If this field is null a
     * RSRuntimeException will instead be thrown with details about the error.
     * This will cause program termaination.
     *
     */
    RSErrorHandler mErrorCallback = null;

    public void setErrorHandler(RSErrorHandler msg) {
        mErrorCallback = msg;
    }
    public RSErrorHandler getErrorHandler() {
        return mErrorCallback;
    }

    /**
     * RenderScript worker threads priority enumeration.  The default value is
     * NORMAL.  Applications wishing to do background processing such as
     * wallpapers should set their priority to LOW to avoid starving forground
     * processes.
     */
    public enum Priority {
        LOW (Process.THREAD_PRIORITY_BACKGROUND + (5 * Process.THREAD_PRIORITY_LESS_FAVORABLE)),
        NORMAL (Process.THREAD_PRIORITY_DISPLAY);

        int mID;
        Priority(int id) {
            mID = id;
        }
    }

    void validate() {
        if (mContext == 0) {
            throw new RSInvalidStateException("Calling RS with no Context active.");
        }
    }


    /**
     * Change the priority of the worker threads for this context.
     *
     * @param p New priority to be set.
     */
    public void setPriority(Priority p) {
        validate();
        nContextSetPriority(p.mID);
    }

    static class MessageThread extends Thread {
        RenderScript mRS;
        boolean mRun = true;
        int[] mAuxData = new int[2];

        static final int RS_MESSAGE_TO_CLIENT_NONE = 0;
        static final int RS_MESSAGE_TO_CLIENT_EXCEPTION = 1;
        static final int RS_MESSAGE_TO_CLIENT_RESIZE = 2;
        static final int RS_MESSAGE_TO_CLIENT_ERROR = 3;
        static final int RS_MESSAGE_TO_CLIENT_USER = 4;

        static final int RS_ERROR_FATAL_UNKNOWN = 0x1000;

        MessageThread(RenderScript rs) {
            super("RSMessageThread");
            mRS = rs;

        }

        public void run() {
            // This function is a temporary solution.  The final solution will
            // used typed allocations where the message id is the type indicator.
            int[] rbuf = new int[16];
            mRS.nContextInitToClient(mRS.mContext);
            while(mRun) {
                rbuf[0] = 0;
                int msg = mRS.nContextPeekMessage(mRS.mContext, mAuxData);
                int size = mAuxData[1];
                int subID = mAuxData[0];

                if (msg == RS_MESSAGE_TO_CLIENT_USER) {
                    if ((size>>2) >= rbuf.length) {
                        rbuf = new int[(size + 3) >> 2];
                    }
                    if (mRS.nContextGetUserMessage(mRS.mContext, rbuf) !=
                        RS_MESSAGE_TO_CLIENT_USER) {
                        throw new RSDriverException("Error processing message from Renderscript.");
                    }

                    if(mRS.mMessageCallback != null) {
                        mRS.mMessageCallback.mData = rbuf;
                        mRS.mMessageCallback.mID = subID;
                        mRS.mMessageCallback.mLength = size;
                        mRS.mMessageCallback.run();
                    } else {
                        throw new RSInvalidStateException("Received a message from the script with no message handler installed.");
                    }
                    continue;
                }

                if (msg == RS_MESSAGE_TO_CLIENT_ERROR) {
                    String e = mRS.nContextGetErrorMessage(mRS.mContext);

                    if (subID >= RS_ERROR_FATAL_UNKNOWN) {
                        throw new RSRuntimeException("Fatal error " + subID + ", details: " + e);
                    }

                    if(mRS.mErrorCallback != null) {
                        mRS.mErrorCallback.mErrorMessage = e;
                        mRS.mErrorCallback.mErrorNum = subID;
                        mRS.mErrorCallback.run();
                    } else {
                        // Do not throw here. In these cases, we do not have
                        // a fatal error.
                    }
                    continue;
                }

                // 2: teardown.
                // But we want to avoid starving other threads during
                // teardown by yielding until the next line in the destructor
                // can execute to set mRun = false
                try {
                    sleep(1, 0);
                } catch(InterruptedException e) {
                }
            }
            Log.d(LOG_TAG, "MessageThread exiting.");
        }
    }

    RenderScript(Context ctx) {
        if (ctx != null) {
            mApplicationContext = ctx.getApplicationContext();
        }
    }

    /**
     * Gets the application context associated with the RenderScript context.
     *
     * @return The application context.
     */
    public final Context getApplicationContext() {
        return mApplicationContext;
    }

    /**
     * Create a basic RenderScript context.
     *
     * @hide
     * @param ctx The context.
     * @return RenderScript
     */
    public static RenderScript create(Context ctx, int sdkVersion) {
        RenderScript rs = new RenderScript(ctx);

        rs.mDev = rs.nDeviceCreate();
        rs.mContext = rs.nContextCreate(rs.mDev, 0, sdkVersion);
        if (rs.mContext == 0) {
            throw new RSDriverException("Failed to create RS context.");
        }
        rs.mMessageThread = new MessageThread(rs);
        rs.mMessageThread.start();
        return rs;
    }

    /**
     * Create a basic RenderScript context.
     *
     * @param ctx The context.
     * @return RenderScript
     */
    public static RenderScript create(Context ctx) {
        int v = ctx.getApplicationInfo().targetSdkVersion;
        return create(ctx, v);
    }

    /**
     * Print the currently available debugging information about the state of
     * the RS context to the log.
     *
     */
    public void contextDump() {
        validate();
        nContextDump(0);
    }

    /**
     * Wait for any commands in the fifo between the java bindings and native to
     * be processed.
     *
     */
    public void finish() {
        nContextFinish();
    }

    /**
     * Destroy this renderscript context.  Once this function is called its no
     * longer legal to use this or any objects created by this context.
     *
     */
    public void destroy() {
        validate();
        nContextDeinitToClient(mContext);
        mMessageThread.mRun = false;
        try {
            mMessageThread.join();
        } catch(InterruptedException e) {
        }

        nContextDestroy();
        mContext = 0;

        nDeviceDestroy(mDev);
        mDev = 0;
    }

    boolean isAlive() {
        return mContext != 0;
    }

    int safeID(BaseObj o) {
        if(o != null) {
            return o.getID(this);
        }
        return 0;
    }
}