android/view/ViewDebug.java

/*
 * Copyright (C) 2007 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.view;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Debug;
import android.os.Environment;
import android.os.Looper;
import android.os.Message;
import android.os.ParcelFileDescriptor;
import android.os.RemoteException;
import android.os.SystemClock;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.Printer;

import java.io.BufferedOutputStream;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

/**
 * Various debugging/tracing tools related to {@link View} and the view hierarchy.
 */
public class ViewDebug {
    /**
     * Log tag used to log errors related to the consistency of the view hierarchy.
     *
     * @hide
     */
    public static final String CONSISTENCY_LOG_TAG = "ViewConsistency";

    /**
     * Flag indicating the consistency check should check layout-related properties.
     *
     * @hide
     */
    public static final int CONSISTENCY_LAYOUT = 0x1;

    /**
     * Flag indicating the consistency check should check drawing-related properties.
     *
     * @hide
     */
    public static final int CONSISTENCY_DRAWING = 0x2;

    /**
     * Enables or disables view hierarchy tracing. Any invoker of
     * {@link #trace(View, android.view.ViewDebug.HierarchyTraceType)} should first
     * check that this value is set to true as not to affect performance.
     */
    public static final boolean TRACE_HIERARCHY = false;

    /**
     * Enables or disables view recycler tracing. Any invoker of
     * {@link #trace(View, android.view.ViewDebug.RecyclerTraceType, int[])} should first
     * check that this value is set to true as not to affect performance.
     */
    public static final boolean TRACE_RECYCLER = false;

    /**
     * Profiles drawing times in the events log.
     *
     * @hide
     */
    public static final boolean DEBUG_PROFILE_DRAWING = false;

    /**
     * Profiles layout times in the events log.
     *
     * @hide
     */
    public static final boolean DEBUG_PROFILE_LAYOUT = false;

    /**
     * Enables detailed logging of drag/drop operations.
     * @hide
     */
    public static final boolean DEBUG_DRAG = false;

    /**
     * Enables logging of factors that affect the latency and responsiveness of an application.
     *
     * Logs the relative difference between the time an event was created and the time it
     * was delivered.
     *
     * Logs the time spent waiting for Surface.lockCanvas() or eglSwapBuffers().
     * This is time that the event loop spends blocked and unresponsive.  Ideally, drawing
     * and animations should be perfectly synchronized with VSYNC so that swap buffers
     * is instantaneous.
     *
     * Logs the time spent in ViewRoot.performTraversals() or ViewRoot.draw().
     * @hide
     */
    public static final boolean DEBUG_LATENCY = false;

    /**
     * <p>Enables or disables views consistency check. Even when this property is enabled,
     * view consistency checks happen only if {@link false} is set
     * to true. The value of this property can be configured externally in one of the
     * following files:</p>
     * <ul>
     *  <li>/system/debug.prop</li>
     *  <li>/debug.prop</li>
     *  <li>/data/debug.prop</li>
     * </ul>
     * @hide
     */
    @Debug.DebugProperty
    public static boolean consistencyCheckEnabled = false;

    /**
     * This annotation can be used to mark fields and methods to be dumped by
     * the view server. Only non-void methods with no arguments can be annotated
     * by this annotation.
     */
    @Target({ ElementType.FIELD, ElementType.METHOD })
    @Retention(RetentionPolicy.RUNTIME)
    public @interface ExportedProperty {
        /**
         * When resolveId is true, and if the annotated field/method return value
         * is an int, the value is converted to an Android's resource name.
         *
         * @return true if the property's value must be transformed into an Android
         *         resource name, false otherwise
         */
        boolean resolveId() default false;

        /**
         * A mapping can be defined to map int values to specific strings. For
         * instance, View.getVisibility() returns 0, 4 or 8. However, these values
         * actually mean VISIBLE, INVISIBLE and GONE. A mapping can be used to see
         * these human readable values:
         *
         * <pre>
         * @ViewDebug.ExportedProperty(mapping = {
         *     @ViewDebug.IntToString(from = 0, to = "VISIBLE"),
         *     @ViewDebug.IntToString(from = 4, to = "INVISIBLE"),
         *     @ViewDebug.IntToString(from = 8, to = "GONE")
         * })
         * public int getVisibility() { ...
         * <pre>
         *
         * @return An array of int to String mappings
         *
         * @see android.view.ViewDebug.IntToString
         */
        IntToString[] mapping() default { };

        /**
         * A mapping can be defined to map array indices to specific strings.
         * A mapping can be used to see human readable values for the indices
         * of an array:
         *
         * <pre>
         * @ViewDebug.ExportedProperty(indexMapping = {
         *     @ViewDebug.IntToString(from = 0, to = "INVALID"),
         *     @ViewDebug.IntToString(from = 1, to = "FIRST"),
         *     @ViewDebug.IntToString(from = 2, to = "SECOND")
         * })
         * private int[] mElements;
         * <pre>
         *
         * @return An array of int to String mappings
         *
         * @see android.view.ViewDebug.IntToString
         * @see #mapping()
         */
        IntToString[] indexMapping() default { };

        /**
         * A flags mapping can be defined to map flags encoded in an integer to
         * specific strings. A mapping can be used to see human readable values
         * for the flags of an integer:
         *
         * <pre>
         * @ViewDebug.ExportedProperty(flagMapping = {
         *     @ViewDebug.FlagToString(mask = ENABLED_MASK, equals = ENABLED, name = "ENABLED"),
         *     @ViewDebug.FlagToString(mask = ENABLED_MASK, equals = DISABLED, name = "DISABLED"),
         * })
         * private int mFlags;
         * <pre>
         *
         * A specified String is output when the following is true:
         *
         * @return An array of int to String mappings
         */
        FlagToString[] flagMapping() default { };

        /**
         * When deep export is turned on, this property is not dumped. Instead, the
         * properties contained in this property are dumped. Each child property
         * is prefixed with the name of this property.
         *
         * @return true if the properties of this property should be dumped
         *
         * @see #prefix()
         */
        boolean deepExport() default false;

        /**
         * The prefix to use on child properties when deep export is enabled
         *
         * @return a prefix as a String
         *
         * @see #deepExport()
         */
        String prefix() default "";

        /**
         * Specifies the category the property falls into, such as measurement,
         * layout, drawing, etc.
         *
         * @return the category as String
         */
        String category() default "";
    }

    /**
     * Defines a mapping from an int value to a String. Such a mapping can be used
     * in a @ExportedProperty to provide more meaningful values to the end user.
     *
     * @see android.view.ViewDebug.ExportedProperty
     */
    @Target({ ElementType.TYPE })
    @Retention(RetentionPolicy.RUNTIME)
    public @interface IntToString {
        /**
         * The original int value to map to a String.
         *
         * @return An arbitrary int value.
         */
        int from();

        /**
         * The String to use in place of the original int value.
         *
         * @return An arbitrary non-null String.
         */
        String to();
    }

    /**
     * Defines a mapping from an flag to a String. Such a mapping can be used
     * in a @ExportedProperty to provide more meaningful values to the end user.
     *
     * @see android.view.ViewDebug.ExportedProperty
     */
    @Target({ ElementType.TYPE })
    @Retention(RetentionPolicy.RUNTIME)
    public @interface FlagToString {
        /**
         * The mask to apply to the original value.
         *
         * @return An arbitrary int value.
         */
        int mask();

        /**
         * The value to compare to the result of:
         * <code>original value &amp; {@link #mask()}</code>.
         *
         * @return An arbitrary value.
         */
        int equals();

        /**
         * The String to use in place of the original int value.
         *
         * @return An arbitrary non-null String.
         */
        String name();

        /**
         * Indicates whether to output the flag when the test is true,
         * or false. Defaults to true.
         */
        boolean outputIf() default true;
    }

    /**
     * This annotation can be used to mark fields and methods to be dumped when
     * the view is captured. Methods with this annotation must have no arguments
     * and must return a valid type of data.
     */
    @Target({ ElementType.FIELD, ElementType.METHOD })
    @Retention(RetentionPolicy.RUNTIME)
    public @interface CapturedViewProperty {
        /**
         * When retrieveReturn is true, we need to retrieve second level methods
         * e.g., we need myView.getFirstLevelMethod().getSecondLevelMethod()
         * we will set retrieveReturn = true on the annotation of
         * myView.getFirstLevelMethod()
         * @return true if we need the second level methods
         */
        boolean retrieveReturn() default false;
    }

    private static HashMap<Class<?>, Method[]> mCapturedViewMethodsForClasses = null;
    private static HashMap<Class<?>, Field[]> mCapturedViewFieldsForClasses = null;

    // Maximum delay in ms after which we stop trying to capture a View's drawing
    private static final int CAPTURE_TIMEOUT = 4000;

    private static final String REMOTE_COMMAND_CAPTURE = "CAPTURE";
    private static final String REMOTE_COMMAND_DUMP = "DUMP";
    private static final String REMOTE_COMMAND_INVALIDATE = "INVALIDATE";
    private static final String REMOTE_COMMAND_REQUEST_LAYOUT = "REQUEST_LAYOUT";
    private static final String REMOTE_PROFILE = "PROFILE";
    private static final String REMOTE_COMMAND_CAPTURE_LAYERS = "CAPTURE_LAYERS";
    private static final String REMOTE_COMMAND_OUTPUT_DISPLAYLIST = "OUTPUT_DISPLAYLIST";

    private static HashMap<Class<?>, Field[]> sFieldsForClasses;
    private static HashMap<Class<?>, Method[]> sMethodsForClasses;
    private static HashMap<AccessibleObject, ExportedProperty> sAnnotations;

    /**
     * Defines the type of hierarhcy trace to output to the hierarchy traces file.
     */
    public enum HierarchyTraceType {
        INVALIDATE,
        INVALIDATE_CHILD,
        INVALIDATE_CHILD_IN_PARENT,
        REQUEST_LAYOUT,
        ON_LAYOUT,
        ON_MEASURE,
        DRAW,
        BUILD_CACHE
    }

    private static BufferedWriter sHierarchyTraces;
    private static ViewRootImpl sHierarhcyRoot;
    private static String sHierarchyTracePrefix;

    /**
     * Defines the type of recycler trace to output to the recycler traces file.
     */
    public enum RecyclerTraceType {
        NEW_VIEW,
        BIND_VIEW,
        RECYCLE_FROM_ACTIVE_HEAP,
        RECYCLE_FROM_SCRAP_HEAP,
        MOVE_TO_SCRAP_HEAP,
        MOVE_FROM_ACTIVE_TO_SCRAP_HEAP
    }

    private static class RecyclerTrace {
        public int view;
        public RecyclerTraceType type;
        public int position;
        public int indexOnScreen;
    }

    private static View sRecyclerOwnerView;
    private static List<View> sRecyclerViews;
    private static List<RecyclerTrace> sRecyclerTraces;
    private static String sRecyclerTracePrefix;

    private static final ThreadLocal<LooperProfiler> sLooperProfilerStorage =
            new ThreadLocal<LooperProfiler>();

    /**
     * Returns the number of instanciated Views.
     *
     * @return The number of Views instanciated in the current process.
     *
     * @hide
     */
    public static long getViewInstanceCount() {
        return Debug.countInstancesOfClass(View.class);
    }

    /**
     * Returns the number of instanciated ViewAncestors.
     *
     * @return The number of ViewAncestors instanciated in the current process.
     *
     * @hide
     */
    public static long getViewRootImplCount() {
        return Debug.countInstancesOfClass(ViewRootImpl.class);
    }

    /**
     * Starts profiling the looper associated with the current thread.
     * You must call {@link #stopLooperProfiling} to end profiling
     * and obtain the traces. Both methods must be invoked on the
     * same thread.
     *
     * @hide
     */
    public static void startLooperProfiling(String path, FileDescriptor fileDescriptor) {
        if (sLooperProfilerStorage.get() == null) {
            LooperProfiler profiler = new LooperProfiler(path, fileDescriptor);
            sLooperProfilerStorage.set(profiler);
            Looper.myLooper().setMessageLogging(profiler);
        }
    }

    /**
     * Stops profiling the looper associated with the current thread.
     *
     * @see #startLooperProfiling(String, java.io.FileDescriptor)
     *
     * @hide
     */
    public static void stopLooperProfiling() {
        LooperProfiler profiler = sLooperProfilerStorage.get();
        if (profiler != null) {
            sLooperProfilerStorage.remove();
            Looper.myLooper().setMessageLogging(null);
            profiler.save();
        }
    }

    private static class LooperProfiler implements Looper.Profiler, Printer {
        private static final String LOG_TAG = "LooperProfiler";

        private static final int TRACE_VERSION_NUMBER = 3;
        private static final int ACTION_EXIT_METHOD = 0x1;
        private static final int HEADER_SIZE = 32;
        private static final String HEADER_MAGIC = "SLOW";
        private static final short HEADER_RECORD_SIZE = (short) 14;

        private final long mTraceWallStart;
        private final long mTraceThreadStart;

        private final ArrayList<Entry> mTraces = new ArrayList<Entry>(512);

        private final HashMap<String, Integer> mTraceNames = new HashMap<String, Integer>(32);
        private int mTraceId = 0;

        private final String mPath;
        private ParcelFileDescriptor mFileDescriptor;

        LooperProfiler(String path, FileDescriptor fileDescriptor) {
            mPath = path;
            try {
                mFileDescriptor = ParcelFileDescriptor.dup(fileDescriptor);
            } catch (IOException e) {
                Log.e(LOG_TAG, "Could not write trace file " + mPath, e);
                throw new RuntimeException(e);
            }
            mTraceWallStart = SystemClock.currentTimeMicro();
            mTraceThreadStart = SystemClock.currentThreadTimeMicro();
        }

        @Override
        public void println(String x) {
            // Ignore messages
        }

        @Override
        public void profile(Message message, long wallStart, long wallTime,
                long threadStart, long threadTime) {
            Entry entry = new Entry();
            entry.traceId = getTraceId(message);
            entry.wallStart = wallStart;
            entry.wallTime = wallTime;
            entry.threadStart = threadStart;
            entry.threadTime = threadTime;

            mTraces.add(entry);
        }

        private int getTraceId(Message message) {
            String name = message.getTarget().getMessageName(message);
            Integer traceId = mTraceNames.get(name);
            if (traceId == null) {
                traceId = mTraceId++ << 4;
                mTraceNames.put(name, traceId);
            }
            return traceId;
        }

        void save() {
            // Don't block the UI thread
            new Thread(new Runnable() {
                @Override
                public void run() {
                    saveTraces();
                }
            }, "LooperProfiler[" + mPath + "]").start();
        }

        private void saveTraces() {
            FileOutputStream fos = new FileOutputStream(mFileDescriptor.getFileDescriptor());
            DataOutputStream out = new DataOutputStream(new BufferedOutputStream(fos));

            try {
                writeHeader(out, mTraceWallStart, mTraceNames, mTraces);
                out.flush();

                writeTraces(fos, out.size(), mTraceWallStart, mTraceThreadStart, mTraces);

                Log.d(LOG_TAG, "Looper traces ready: " + mPath);
            } catch (IOException e) {
                Log.e(LOG_TAG, "Could not write trace file " + mPath, e);
            } finally {
                try {
                    out.close();
                } catch (IOException e) {
                    Log.e(LOG_TAG, "Could not write trace file " + mPath, e);
                }
                try {
                    mFileDescriptor.close();
                } catch (IOException e) {
                    Log.e(LOG_TAG, "Could not write trace file " + mPath, e);
                }
            }
        }

        private static void writeTraces(FileOutputStream out, long offset, long wallStart,
                long threadStart, ArrayList<Entry> entries) throws IOException {

            FileChannel channel = out.getChannel();

            // Header
            ByteBuffer buffer = ByteBuffer.allocateDirect(HEADER_SIZE);
            buffer.put(HEADER_MAGIC.getBytes());
            buffer = buffer.order(ByteOrder.LITTLE_ENDIAN);
            buffer.putShort((short) TRACE_VERSION_NUMBER);    // version
            buffer.putShort((short) HEADER_SIZE);             // offset to data
            buffer.putLong(wallStart);                        // start time in usec
            buffer.putShort(HEADER_RECORD_SIZE);              // size of a record in bytes
            // padding to 32 bytes
            for (int i = 0; i < HEADER_SIZE - 18; i++) {
                buffer.put((byte) 0);
            }

            buffer.flip();
            channel.position(offset).write(buffer);

            buffer = ByteBuffer.allocateDirect(14).order(ByteOrder.LITTLE_ENDIAN);
            for (Entry entry : entries) {
                buffer.putShort((short) 1);   // we simulate only one thread
                buffer.putInt(entry.traceId); // entering method
                buffer.putInt((int) (entry.threadStart - threadStart));
                buffer.putInt((int) (entry.wallStart - wallStart));

                buffer.flip();
                channel.write(buffer);
                buffer.clear();

                buffer.putShort((short) 1);
                buffer.putInt(entry.traceId | ACTION_EXIT_METHOD); // exiting method
                buffer.putInt((int) (entry.threadStart + entry.threadTime - threadStart));
                buffer.putInt((int) (entry.wallStart + entry.wallTime - wallStart));

                buffer.flip();
                channel.write(buffer);
                buffer.clear();
            }

            channel.close();
        }

        private static void writeHeader(DataOutputStream out, long start,
                HashMap<String, Integer> names, ArrayList<Entry> entries) throws IOException {

            Entry last = entries.get(entries.size() - 1);
            long wallTotal = (last.wallStart + last.wallTime) - start;

            startSection("version", out);
            addValue(null, Integer.toString(TRACE_VERSION_NUMBER), out);
            addValue("data-file-overflow", "false", out);
            addValue("clock", "dual", out);
            addValue("elapsed-time-usec", Long.toString(wallTotal), out);
            addValue("num-method-calls", Integer.toString(entries.size()), out);
            addValue("clock-call-overhead-nsec", "1", out);
            addValue("vm", "dalvik", out);

            startSection("threads", out);
            addThreadId(1, "main", out);

            startSection("methods", out);
            addMethods(names, out);

            startSection("end", out);
        }

        private static void addMethods(HashMap<String, Integer> names, DataOutputStream out)
                throws IOException {

            for (Map.Entry<String, Integer> name : names.entrySet()) {
                out.writeBytes(String.format("0x%08x\tEventQueue\t%s\t()V\tLooper\t-2\n",
                        name.getValue(), name.getKey()));
            }
        }

        private static void addThreadId(int id, String name, DataOutputStream out)
                throws IOException {

            out.writeBytes(Integer.toString(id) + '\t' + name + '\n');
        }

        private static void addValue(String name, String value, DataOutputStream out)
                throws IOException {

            if (name != null) {
                out.writeBytes(name + "=");
            }
            out.writeBytes(value + '\n');
        }

        private static void startSection(String name, DataOutputStream out) throws IOException {
            out.writeBytes("*" + name + '\n');
        }

        static class Entry {
            int traceId;
            long wallStart;
            long wallTime;
            long threadStart;
            long threadTime;
        }
    }

    /**
     * Outputs a trace to the currently opened recycler traces. The trace records the type of
     * recycler action performed on the supplied view as well as a number of parameters.
     *
     * @param view the view to trace
     * @param type the type of the trace
     * @param parameters parameters depending on the type of the trace
     */
    public static void trace(View view, RecyclerTraceType type, int... parameters) {
        if (sRecyclerOwnerView == null || sRecyclerViews == null) {
            return;
        }

        if (!sRecyclerViews.contains(view)) {
            sRecyclerViews.add(view);
        }

        final int index = sRecyclerViews.indexOf(view);

        RecyclerTrace trace = new RecyclerTrace();
        trace.view = index;
        trace.type = type;
        trace.position = parameters[0];
        trace.indexOnScreen = parameters[1];

        sRecyclerTraces.add(trace);
    }

    /**
     * Starts tracing the view recycler of the specified view. The trace is identified by a prefix,
     * used to build the traces files names: <code>/EXTERNAL/view-recycler/PREFIX.traces</code> and
     * <code>/EXTERNAL/view-recycler/PREFIX.recycler</code>.
     *
     * Only one view recycler can be traced at the same time. After calling this method, any
     * other invocation will result in a <code>IllegalStateException</code> unless
     * {@link #stopRecyclerTracing()} is invoked before.
     *
     * Traces files are created only after {@link #stopRecyclerTracing()} is invoked.
     *
     * This method will return immediately if TRACE_RECYCLER is false.
     *
     * @param prefix the traces files name prefix
     * @param view the view whose recycler must be traced
     *
     * @see #stopRecyclerTracing()
     * @see #trace(View, android.view.ViewDebug.RecyclerTraceType, int[])
     */
    public static void startRecyclerTracing(String prefix, View view) {
        //noinspection PointlessBooleanExpression,ConstantConditions
        if (!TRACE_RECYCLER) {
            return;
        }

        if (sRecyclerOwnerView != null) {
            throw new IllegalStateException("You must call stopRecyclerTracing() before running" +
                " a new trace!");
        }

        sRecyclerTracePrefix = prefix;
        sRecyclerOwnerView = view;
        sRecyclerViews = new ArrayList<View>();
        sRecyclerTraces = new LinkedList<RecyclerTrace>();
    }

    /**
     * Stops the current view recycer tracing.
     *
     * Calling this method creates the file <code>/EXTERNAL/view-recycler/PREFIX.traces</code>
     * containing all the traces (or method calls) relative to the specified view's recycler.
     *
     * Calling this method creates the file <code>/EXTERNAL/view-recycler/PREFIX.recycler</code>
     * containing all of the views used by the recycler of the view supplied to
     * {@link #startRecyclerTracing(String, View)}.
     *
     * This method will return immediately if TRACE_RECYCLER is false.
     *
     * @see #startRecyclerTracing(String, View)
     * @see #trace(View, android.view.ViewDebug.RecyclerTraceType, int[])
     */
    public static void stopRecyclerTracing() {
        //noinspection PointlessBooleanExpression,ConstantConditions
        if (!TRACE_RECYCLER) {
            return;
        }

        if (sRecyclerOwnerView == null || sRecyclerViews == null) {
            throw new IllegalStateException("You must call startRecyclerTracing() before" +
                " stopRecyclerTracing()!");
        }

        File recyclerDump = new File(Environment.getExternalStorageDirectory(), "view-recycler/");
        //noinspection ResultOfMethodCallIgnored
        recyclerDump.mkdirs();

        recyclerDump = new File(recyclerDump, sRecyclerTracePrefix + ".recycler");
        try {
            final BufferedWriter out = new BufferedWriter(new FileWriter(recyclerDump), 8 * 1024);

            for (View view : sRecyclerViews) {
                final String name = view.getClass().getName();
                out.write(name);
                out.newLine();
            }

            out.close();
        } catch (IOException e) {
            Log.e("View", "Could not dump recycler content");
            return;
        }

        recyclerDump = new File(Environment.getExternalStorageDirectory(), "view-recycler/");
        recyclerDump = new File(recyclerDump, sRecyclerTracePrefix + ".traces");
        try {
            if (recyclerDump.exists()) {
                //noinspection ResultOfMethodCallIgnored
                recyclerDump.delete();
            }
            final FileOutputStream file = new FileOutputStream(recyclerDump);
            final DataOutputStream out = new DataOutputStream(file);

            for (RecyclerTrace trace : sRecyclerTraces) {
                out.writeInt(trace.view);
                out.writeInt(trace.type.ordinal());
                out.writeInt(trace.position);
                out.writeInt(trace.indexOnScreen);
                out.flush();
            }

            out.close();
        } catch (IOException e) {
            Log.e("View", "Could not dump recycler traces");
            return;
        }

        sRecyclerViews.clear();
        sRecyclerViews = null;

        sRecyclerTraces.clear();
        sRecyclerTraces = null;

        sRecyclerOwnerView = null;
    }

    /**
     * Outputs a trace to the currently opened traces file. The trace contains the class name
     * and instance's hashcode of the specified view as well as the supplied trace type.
     *
     * @param view the view to trace
     * @param type the type of the trace
     */
    public static void trace(View view, HierarchyTraceType type) {
        if (sHierarchyTraces == null) {
            return;
        }

        try {
            sHierarchyTraces.write(type.name());
            sHierarchyTraces.write(' ');
            sHierarchyTraces.write(view.getClass().getName());
            sHierarchyTraces.write('@');
            sHierarchyTraces.write(Integer.toHexString(view.hashCode()));
            sHierarchyTraces.newLine();
        } catch (IOException e) {
            Log.w("View", "Error while dumping trace of type " + type + " for view " + view);
        }
    }

    /**
     * Starts tracing the view hierarchy of the specified view. The trace is identified by a prefix,
     * used to build the traces files names: <code>/EXTERNAL/view-hierarchy/PREFIX.traces</code> and
     * <code>/EXTERNAL/view-hierarchy/PREFIX.tree</code>.
     *
     * Only one view hierarchy can be traced at the same time. After calling this method, any
     * other invocation will result in a <code>IllegalStateException</code> unless
     * {@link #stopHierarchyTracing()} is invoked before.
     *
     * Calling this method creates the file <code>/EXTERNAL/view-hierarchy/PREFIX.traces</code>
     * containing all the traces (or method calls) relative to the specified view's hierarchy.
     *
     * This method will return immediately if TRACE_HIERARCHY is false.
     *
     * @param prefix the traces files name prefix
     * @param view the view whose hierarchy must be traced
     *
     * @see #stopHierarchyTracing()
     * @see #trace(View, android.view.ViewDebug.HierarchyTraceType)
     */
    public static void startHierarchyTracing(String prefix, View view) {
        //noinspection PointlessBooleanExpression,ConstantConditions
        if (!TRACE_HIERARCHY) {
            return;
        }

        if (sHierarhcyRoot != null) {
            throw new IllegalStateException("You must call stopHierarchyTracing() before running" +
                " a new trace!");
        }

        File hierarchyDump = new File(Environment.getExternalStorageDirectory(), "view-hierarchy/");
        //noinspection ResultOfMethodCallIgnored
        hierarchyDump.mkdirs();

        hierarchyDump = new File(hierarchyDump, prefix + ".traces");
        sHierarchyTracePrefix = prefix;

        try {
            sHierarchyTraces = new BufferedWriter(new FileWriter(hierarchyDump), 8 * 1024);
        } catch (IOException e) {
            Log.e("View", "Could not dump view hierarchy");
            return;
        }

        sHierarhcyRoot = (ViewRootImpl) view.getRootView().getParent();
    }

    /**
     * Stops the current view hierarchy tracing. This method closes the file
     * <code>/EXTERNAL/view-hierarchy/PREFIX.traces</code>.
     *
     * Calling this method creates the file <code>/EXTERNAL/view-hierarchy/PREFIX.tree</code>
     * containing the view hierarchy of the view supplied to
     * {@link #startHierarchyTracing(String, View)}.
     *
     * This method will return immediately if TRACE_HIERARCHY is false.
     *
     * @see #startHierarchyTracing(String, View)
     * @see #trace(View, android.view.ViewDebug.HierarchyTraceType)
     */
    public static void stopHierarchyTracing() {
        //noinspection PointlessBooleanExpression,ConstantConditions
        if (!TRACE_HIERARCHY) {
            return;
        }

        if (sHierarhcyRoot == null || sHierarchyTraces == null) {
            throw new IllegalStateException("You must call startHierarchyTracing() before" +
                " stopHierarchyTracing()!");
        }

        try {
            sHierarchyTraces.close();
        } catch (IOException e) {
            Log.e("View", "Could not write view traces");
        }
        sHierarchyTraces = null;

        File hierarchyDump = new File(Environment.getExternalStorageDirectory(), "view-hierarchy/");
        //noinspection ResultOfMethodCallIgnored
        hierarchyDump.mkdirs();
        hierarchyDump = new File(hierarchyDump, sHierarchyTracePrefix + ".tree");

        BufferedWriter out;
        try {
            out = new BufferedWriter(new FileWriter(hierarchyDump), 8 * 1024);
        } catch (IOException e) {
            Log.e("View", "Could not dump view hierarchy");
            return;
        }

        View view = sHierarhcyRoot.getView();
        if (view instanceof ViewGroup) {
            ViewGroup group = (ViewGroup) view;
            dumpViewHierarchy(group, out, 0);
            try {
                out.close();
            } catch (IOException e) {
                Log.e("View", "Could not dump view hierarchy");
            }
        }

        sHierarhcyRoot = null;
    }

    static void dispatchCommand(View view, String command, String parameters,
            OutputStream clientStream) throws IOException {

        // Paranoid but safe...
        view = view.getRootView();

        if (REMOTE_COMMAND_DUMP.equalsIgnoreCase(command)) {
            dump(view, clientStream);
        } else if (REMOTE_COMMAND_CAPTURE_LAYERS.equalsIgnoreCase(command)) {
            captureLayers(view, new DataOutputStream(clientStream));
        } else {
            final String[] params = parameters.split(" ");
            if (REMOTE_COMMAND_CAPTURE.equalsIgnoreCase(command)) {
                capture(view, clientStream, params[0]);
            } else if (REMOTE_COMMAND_OUTPUT_DISPLAYLIST.equalsIgnoreCase(command)) {
                outputDisplayList(view, params[0]);
            } else if (REMOTE_COMMAND_INVALIDATE.equalsIgnoreCase(command)) {
                invalidate(view, params[0]);
            } else if (REMOTE_COMMAND_REQUEST_LAYOUT.equalsIgnoreCase(command)) {
                requestLayout(view, params[0]);
            } else if (REMOTE_PROFILE.equalsIgnoreCase(command)) {
                profile(view, clientStream, params[0]);
            }
        }
    }

    private static View findView(View root, String parameter) {
        // Look by type/hashcode
        if (parameter.indexOf('@') != -1) {
            final String[] ids = parameter.split("@");
            final String className = ids[0];
            final int hashCode = (int) Long.parseLong(ids[1], 16);

            View view = root.getRootView();
            if (view instanceof ViewGroup) {
                return findView((ViewGroup) view, className, hashCode);
            }
        } else {
            // Look by id
            final int id = root.getResources().getIdentifier(parameter, null, null);
            return root.getRootView().findViewById(id);
        }

        return null;
    }

    private static void invalidate(View root, String parameter) {
        final View view = findView(root, parameter);
        if (view != null) {
            view.postInvalidate();
        }
    }

    private static void requestLayout(View root, String parameter) {
        final View view = findView(root, parameter);
        if (view != null) {
            root.post(new Runnable() {
                public void run() {
                    view.requestLayout();
                }
            });
        }
    }

    private static void profile(View root, OutputStream clientStream, String parameter)
            throws IOException {

        final View view = findView(root, parameter);
        BufferedWriter out = null;
        try {
            out = new BufferedWriter(new OutputStreamWriter(clientStream), 32 * 1024);

            if (view != null) {
                profileViewAndChildren(view, out);
            } else {
                out.write("-1 -1 -1");
                out.newLine();
            }
            out.write("DONE.");
            out.newLine();
        } catch (Exception e) {
            android.util.Log.w("View", "Problem profiling the view:", e);
        } finally {
            if (out != null) {
                out.close();
            }
        }
    }

    private static void profileViewAndChildren(final View view, BufferedWriter out)
            throws IOException {
        profileViewAndChildren(view, out, true);
    }

    private static void profileViewAndChildren(final View view, BufferedWriter out, boolean root)
            throws IOException {

        long durationMeasure =
                (root || (view.mPrivateFlags & View.MEASURED_DIMENSION_SET) != 0) ? profileViewOperation(
                        view, new ViewOperation<Void>() {
                            public Void[] pre() {
                                forceLayout(view);
                                return null;
                            }

                            private void forceLayout(View view) {
                                view.forceLayout();
                                if (view instanceof ViewGroup) {
                                    ViewGroup group = (ViewGroup) view;
                                    final int count = group.getChildCount();
                                    for (int i = 0; i < count; i++) {
                                        forceLayout(group.getChildAt(i));
                                    }
                                }
                            }

                            public void run(Void... data) {
                                view.measure(view.mOldWidthMeasureSpec, view.mOldHeightMeasureSpec);
                            }

                            public void post(Void... data) {
                            }
                        })
                        : 0;
        long durationLayout =
                (root || (view.mPrivateFlags & View.LAYOUT_REQUIRED) != 0) ? profileViewOperation(
                        view, new ViewOperation<Void>() {
                            public Void[] pre() {
                                return null;
                            }

                            public void run(Void... data) {
                                view.layout(view.mLeft, view.mTop, view.mRight, view.mBottom);
                            }

                            public void post(Void... data) {
                            }
                        }) : 0;
        long durationDraw =
                (root || !view.willNotDraw() || (view.mPrivateFlags & View.DRAWN) != 0) ? profileViewOperation(
                        view,
                        new ViewOperation<Object>() {
                            public Object[] pre() {
                                final DisplayMetrics metrics =
                                        (view != null && view.getResources() != null) ?
                                                view.getResources().getDisplayMetrics() : null;
                                final Bitmap bitmap = metrics != null ?
                                        Bitmap.createBitmap(metrics.widthPixels,
                                                metrics.heightPixels, Bitmap.Config.RGB_565) : null;
                                final Canvas canvas = bitmap != null ? new Canvas(bitmap) : null;
                                return new Object[] {
                                        bitmap, canvas
                                };
                            }

                            public void run(Object... data) {
                                if (data[1] != null) {
                                    view.draw((Canvas) data[1]);
                                }
                            }

                            public void post(Object... data) {
                                if (data[1] != null) {
                                    ((Canvas) data[1]).setBitmap(null);
                                }
                                if (data[0] != null) {
                                    ((Bitmap) data[0]).recycle();
                                }
                            }
                        }) : 0;
        out.write(String.valueOf(durationMeasure));
        out.write(' ');
        out.write(String.valueOf(durationLayout));
        out.write(' ');
        out.write(String.valueOf(durationDraw));
        out.newLine();
        if (view instanceof ViewGroup) {
            ViewGroup group = (ViewGroup) view;
            final int count = group.getChildCount();
            for (int i = 0; i < count; i++) {
                profileViewAndChildren(group.getChildAt(i), out, false);
            }
        }
    }

    interface ViewOperation<T> {
        T[] pre();
        void run(T... data);
        void post(T... data);
    }

    private static <T> long profileViewOperation(View view, final ViewOperation<T> operation) {
        final CountDownLatch latch = new CountDownLatch(1);
        final long[] duration = new long[1];

        view.post(new Runnable() {
            public void run() {
                try {
                    T[] data = operation.pre();
                    long start = Debug.threadCpuTimeNanos();
                    //noinspection unchecked
                    operation.run(data);
                    duration[0] = Debug.threadCpuTimeNanos() - start;
                    //noinspection unchecked
                    operation.post(data);
                } finally {
                    latch.countDown();
                }
            }
        });

        try {
            if (!latch.await(CAPTURE_TIMEOUT, TimeUnit.MILLISECONDS)) {
                Log.w("View", "Could not complete the profiling of the view " + view);
                return -1;
            }
        } catch (InterruptedException e) {
            Log.w("View", "Could not complete the profiling of the view " + view);
            Thread.currentThread().interrupt();
            return -1;
        }

        return duration[0];
    }

    private static void captureLayers(View root, final DataOutputStream clientStream)
            throws IOException {

        try {
            Rect outRect = new Rect();
            try {
                root.mAttachInfo.mSession.getDisplayFrame(root.mAttachInfo.mWindow, outRect);
            } catch (RemoteException e) {
                // Ignore
            }

            clientStream.writeInt(outRect.width());
            clientStream.writeInt(outRect.height());

            captureViewLayer(root, clientStream, true);

            clientStream.write(2);
        } finally {
            clientStream.close();
        }
    }

    private static void captureViewLayer(View view, DataOutputStream clientStream, boolean visible)
            throws IOException {

        final boolean localVisible = view.getVisibility() == View.VISIBLE && visible;

        if ((view.mPrivateFlags & View.SKIP_DRAW) != View.SKIP_DRAW) {
            final int id = view.getId();
            String name = view.getClass().getSimpleName();
            if (id != View.NO_ID) {
                name = resolveId(view.getContext(), id).toString();
            }

            clientStream.write(1);
            clientStream.writeUTF(name);
            clientStream.writeByte(localVisible ? 1 : 0);

            int[] position = new int[2];
            // XXX: Should happen on the UI thread
            view.getLocationInWindow(position);

            clientStream.writeInt(position[0]);
            clientStream.writeInt(position[1]);
            clientStream.flush();

            Bitmap b = performViewCapture(view, true);
            if (b != null) {
                ByteArrayOutputStream arrayOut = new ByteArrayOutputStream(b.getWidth() *
                        b.getHeight() * 2);
                b.compress(Bitmap.CompressFormat.PNG, 100, arrayOut);
                clientStream.writeInt(arrayOut.size());
                arrayOut.writeTo(clientStream);
            }
            clientStream.flush();
        }

        if (view instanceof ViewGroup) {
            ViewGroup group = (ViewGroup) view;
            int count = group.getChildCount();

            for (int i = 0; i < count; i++) {
                captureViewLayer(group.getChildAt(i), clientStream, localVisible);
            }
        }
    }

    private static void outputDisplayList(View root, String parameter) throws IOException {
        final View view = findView(root, parameter);
        view.getViewRootImpl().outputDisplayList(view);
    }

    private static void capture(View root, final OutputStream clientStream, String parameter)
            throws IOException {

        final View captureView = findView(root, parameter);
        Bitmap b = performViewCapture(captureView, false);

        if (b == null) {
            Log.w("View", "Failed to create capture bitmap!");
            // Send an empty one so that it doesn't get stuck waiting for
            // something.
            b = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888);
        }

        BufferedOutputStream out = null;
        try {
            out = new BufferedOutputStream(clientStream, 32 * 1024);
            b.compress(Bitmap.CompressFormat.PNG, 100, out);
            out.flush();
        } finally {
            if (out != null) {
                out.close();
            }
            b.recycle();
        }
    }

    private static Bitmap performViewCapture(final View captureView, final boolean skpiChildren) {
        if (captureView != null) {
            final CountDownLatch latch = new CountDownLatch(1);
            final Bitmap[] cache = new Bitmap[1];

            captureView.post(new Runnable() {
                public void run() {
                    try {
                        cache[0] = captureView.createSnapshot(
                                Bitmap.Config.ARGB_8888, 0, skpiChildren);
                    } catch (OutOfMemoryError e) {
                        Log.w("View", "Out of memory for bitmap");
                    } finally {
                        latch.countDown();
                    }
                }
            });

            try {
                latch.await(CAPTURE_TIMEOUT, TimeUnit.MILLISECONDS);
                return cache[0];
            } catch (InterruptedException e) {
                Log.w("View", "Could not complete the capture of the view " + captureView);
                Thread.currentThread().interrupt();
            }
        }

        return null;
    }

    private static void dump(View root, OutputStream clientStream) throws IOException {
        BufferedWriter out = null;
        try {
            out = new BufferedWriter(new OutputStreamWriter(clientStream, "utf-8"), 32 * 1024);
            View view = root.getRootView();
            if (view instanceof ViewGroup) {
                ViewGroup group = (ViewGroup) view;
                dumpViewHierarchyWithProperties(group.getContext(), group, out, 0);
            }
            out.write("DONE.");
            out.newLine();
        } catch (Exception e) {
            android.util.Log.w("View", "Problem dumping the view:", e);
        } finally {
            if (out != null) {
                out.close();
            }
        }
    }

    private static View findView(ViewGroup group, String className, int hashCode) {
        if (isRequestedView(group, className, hashCode)) {
            return group;
        }

        final int count = group.getChildCount();
        for (int i = 0; i < count; i++) {
            final View view = group.getChildAt(i);
            if (view instanceof ViewGroup) {
                final View found = findView((ViewGroup) view, className, hashCode);
                if (found != null) {
                    return found;
                }
            } else if (isRequestedView(view, className, hashCode)) {
                return view;
            }
        }

        return null;
    }

    private static boolean isRequestedView(View view, String className, int hashCode) {
        return view.getClass().getName().equals(className) && view.hashCode() == hashCode;
    }

    private static void dumpViewHierarchyWithProperties(Context context, ViewGroup group,
            BufferedWriter out, int level) {
        if (!dumpViewWithProperties(context, group, out, level)) {
            return;
        }

        final int count = group.getChildCount();
        for (int i = 0; i < count; i++) {
            final View view = group.getChildAt(i);
            if (view instanceof ViewGroup) {
                dumpViewHierarchyWithProperties(context, (ViewGroup) view, out, level + 1);
            } else {
                dumpViewWithProperties(context, view, out, level + 1);
            }
        }
    }

    private static boolean dumpViewWithProperties(Context context, View view,
            BufferedWriter out, int level) {

        try {
            for (int i = 0; i < level; i++) {
                out.write(' ');
            }
            out.write(view.getClass().getName());
            out.write('@');
            out.write(Integer.toHexString(view.hashCode()));
            out.write(' ');
            dumpViewProperties(context, view, out);
            out.newLine();
        } catch (IOException e) {
            Log.w("View", "Error while dumping hierarchy tree");
            return false;
        }
        return true;
    }

    private static Field[] getExportedPropertyFields(Class<?> klass) {
        if (sFieldsForClasses == null) {
            sFieldsForClasses = new HashMap<Class<?>, Field[]>();
        }
        if (sAnnotations == null) {
            sAnnotations = new HashMap<AccessibleObject, ExportedProperty>(512);
        }

        final HashMap<Class<?>, Field[]> map = sFieldsForClasses;

        Field[] fields = map.get(klass);
        if (fields != null) {
            return fields;
        }

        final ArrayList<Field> foundFields = new ArrayList<Field>();
        fields = klass.getDeclaredFields();

        int count = fields.length;
        for (int i = 0; i < count; i++) {
            final Field field = fields[i];
            if (field.isAnnotationPresent(ExportedProperty.class)) {
                field.setAccessible(true);
                foundFields.add(field);
                sAnnotations.put(field, field.getAnnotation(ExportedProperty.class));
            }
        }

        fields = foundFields.toArray(new Field[foundFields.size()]);
        map.put(klass, fields);

        return fields;
    }

    private static Method[] getExportedPropertyMethods(Class<?> klass) {
        if (sMethodsForClasses == null) {
            sMethodsForClasses = new HashMap<Class<?>, Method[]>(100);
        }
        if (sAnnotations == null) {
            sAnnotations = new HashMap<AccessibleObject, ExportedProperty>(512);
        }

        final HashMap<Class<?>, Method[]> map = sMethodsForClasses;

        Method[] methods = map.get(klass);
        if (methods != null) {
            return methods;
        }

        final ArrayList<Method> foundMethods = new ArrayList<Method>();
        methods = klass.getDeclaredMethods();

        int count = methods.length;
        for (int i = 0; i < count; i++) {
            final Method method = methods[i];
            if (method.getParameterTypes().length == 0 &&
                    method.isAnnotationPresent(ExportedProperty.class) &&
                    method.getReturnType() != Void.class) {
                method.setAccessible(true);
                foundMethods.add(method);
                sAnnotations.put(method, method.getAnnotation(ExportedProperty.class));
            }
        }

        methods = foundMethods.toArray(new Method[foundMethods.size()]);
        map.put(klass, methods);

        return methods;
    }

    private static void dumpViewProperties(Context context, Object view,
            BufferedWriter out) throws IOException {

        dumpViewProperties(context, view, out, "");
    }

    private static void dumpViewProperties(Context context, Object view,
            BufferedWriter out, String prefix) throws IOException {

        Class<?> klass = view.getClass();

        do {
            exportFields(context, view, out, klass, prefix);
            exportMethods(context, view, out, klass, prefix);
            klass = klass.getSuperclass();
        } while (klass != Object.class);
    }

    private static void exportMethods(Context context, Object view, BufferedWriter out,
            Class<?> klass, String prefix) throws IOException {

        final Method[] methods = getExportedPropertyMethods(klass);

        int count = methods.length;
        for (int i = 0; i < count; i++) {
            final Method method = methods[i];
            //noinspection EmptyCatchBlock
            try {
                // TODO: This should happen on the UI thread
                Object methodValue = method.invoke(view, (Object[]) null);
                final Class<?> returnType = method.getReturnType();
                final ExportedProperty property = sAnnotations.get(method);
                String categoryPrefix =
                        property.category().length() != 0 ? property.category() + ":" : "";

                if (returnType == int.class) {

                    if (property.resolveId() && context != null) {
                        final int id = (Integer) methodValue;
                        methodValue = resolveId(context, id);
                    } else {
                        final FlagToString[] flagsMapping = property.flagMapping();
                        if (flagsMapping.length > 0) {
                            final int intValue = (Integer) methodValue;
                            final String valuePrefix =
                                    categoryPrefix + prefix + method.getName() + '_';
                            exportUnrolledFlags(out, flagsMapping, intValue, valuePrefix);
                        }

                        final IntToString[] mapping = property.mapping();
                        if (mapping.length > 0) {
                            final int intValue = (Integer) methodValue;
                            boolean mapped = false;
                            int mappingCount = mapping.length;
                            for (int j = 0; j < mappingCount; j++) {
                                final IntToString mapper = mapping[j];
                                if (mapper.from() == intValue) {
                                    methodValue = mapper.to();
                                    mapped = true;
                                    break;
                                }
                            }

                            if (!mapped) {
                                methodValue = intValue;
                            }
                        }
                    }
                } else if (returnType == int[].class) {
                    final int[] array = (int[]) methodValue;
                    final String valuePrefix = categoryPrefix + prefix + method.getName() + '_';
                    final String suffix = "()";

                    exportUnrolledArray(context, out, property, array, valuePrefix, suffix);

                    // Probably want to return here, same as for fields.
                    return;
                } else if (!returnType.isPrimitive()) {
                    if (property.deepExport()) {
                        dumpViewProperties(context, methodValue, out, prefix + property.prefix());
                        continue;
                    }
                }

                writeEntry(out, categoryPrefix + prefix, method.getName(), "()", methodValue);
            } catch (IllegalAccessException e) {
            } catch (InvocationTargetException e) {
            }
        }
    }

    private static void exportFields(Context context, Object view, BufferedWriter out,
            Class<?> klass, String prefix) throws IOException {

        final Field[] fields = getExportedPropertyFields(klass);

        int count = fields.length;
        for (int i = 0; i < count; i++) {
            final Field field = fields[i];

            //noinspection EmptyCatchBlock
            try {
                Object fieldValue = null;
                final Class<?> type = field.getType();
                final ExportedProperty property = sAnnotations.get(field);
                String categoryPrefix =
                        property.category().length() != 0 ? property.category() + ":" : "";

                if (type == int.class) {

                    if (property.resolveId() && context != null) {
                        final int id = field.getInt(view);
                        fieldValue = resolveId(context, id);
                    } else {
                        final FlagToString[] flagsMapping = property.flagMapping();
                        if (flagsMapping.length > 0) {
                            final int intValue = field.getInt(view);
                            final String valuePrefix =
                                    categoryPrefix + prefix + field.getName() + '_';
                            exportUnrolledFlags(out, flagsMapping, intValue, valuePrefix);
                        }

                        final IntToString[] mapping = property.mapping();
                        if (mapping.length > 0) {
                            final int intValue = field.getInt(view);
                            int mappingCount = mapping.length;
                            for (int j = 0; j < mappingCount; j++) {
                                final IntToString mapped = mapping[j];
                                if (mapped.from() == intValue) {
                                    fieldValue = mapped.to();
                                    break;
                                }
                            }

                            if (fieldValue == null) {
                                fieldValue = intValue;
                            }
                        }
                    }
                } else if (type == int[].class) {
                    final int[] array = (int[]) field.get(view);
                    final String valuePrefix = categoryPrefix + prefix + field.getName() + '_';
                    final String suffix = "";

                    exportUnrolledArray(context, out, property, array, valuePrefix, suffix);

                    // We exit here!
                    return;
                } else if (!type.isPrimitive()) {
                    if (property.deepExport()) {
                        dumpViewProperties(context, field.get(view), out, prefix
                                + property.prefix());
                        continue;
                    }
                }

                if (fieldValue == null) {
                    fieldValue = field.get(view);
                }

                writeEntry(out, categoryPrefix + prefix, field.getName(), "", fieldValue);
            } catch (IllegalAccessException e) {
            }
        }
    }

    private static void writeEntry(BufferedWriter out, String prefix, String name,
            String suffix, Object value) throws IOException {

        out.write(prefix);
        out.write(name);
        out.write(suffix);
        out.write("=");
        writeValue(out, value);
        out.write(' ');
    }

    private static void exportUnrolledFlags(BufferedWriter out, FlagToString[] mapping,
            int intValue, String prefix) throws IOException {

        final int count = mapping.length;
        for (int j = 0; j < count; j++) {
            final FlagToString flagMapping = mapping[j];
            final boolean ifTrue = flagMapping.outputIf();
            final int maskResult = intValue & flagMapping.mask();
            final boolean test = maskResult == flagMapping.equals();
            if ((test && ifTrue) || (!test && !ifTrue)) {
                final String name = flagMapping.name();
                final String value = "0x" + Integer.toHexString(maskResult);
                writeEntry(out, prefix, name, "", value);
            }
        }
    }

    private static void exportUnrolledArray(Context context, BufferedWriter out,
            ExportedProperty property, int[] array, String prefix, String suffix)
            throws IOException {

        final IntToString[] indexMapping = property.indexMapping();
        final boolean hasIndexMapping = indexMapping.length > 0;

        final IntToString[] mapping = property.mapping();
        final boolean hasMapping = mapping.length > 0;

        final boolean resolveId = property.resolveId() && context != null;
        final int valuesCount = array.length;

        for (int j = 0; j < valuesCount; j++) {
            String name;
            String value = null;

            final int intValue = array[j];

            name = String.valueOf(j);
            if (hasIndexMapping) {
                int mappingCount = indexMapping.length;
                for (int k = 0; k < mappingCount; k++) {
                    final IntToString mapped = indexMapping[k];
                    if (mapped.from() == j) {
                        name = mapped.to();
                        break;
                    }
                }
            }

            if (hasMapping) {
                int mappingCount = mapping.length;
                for (int k = 0; k < mappingCount; k++) {
                    final IntToString mapped = mapping[k];
                    if (mapped.from() == intValue) {
                        value = mapped.to();
                        break;
                    }
                }
            }

            if (resolveId) {
                if (value == null) value = (String) resolveId(context, intValue);
            } else {
                value = String.valueOf(intValue);
            }

            writeEntry(out, prefix, name, suffix, value);
        }
    }

    static Object resolveId(Context context, int id) {
        Object fieldValue;
        final Resources resources = context.getResources();
        if (id >= 0) {
            try {
                fieldValue = resources.getResourceTypeName(id) + '/' +
                        resources.getResourceEntryName(id);
            } catch (Resources.NotFoundException e) {
                fieldValue = "id/0x" + Integer.toHexString(id);
            }
        } else {
            fieldValue = "NO_ID";
        }
        return fieldValue;
    }

    private static void writeValue(BufferedWriter out, Object value) throws IOException {
        if (value != null) {
            String output = value.toString().replace("\n", "\\n");
            out.write(String.valueOf(output.length()));
            out.write(",");
            out.write(output);
        } else {
            out.write("4,null");
        }
    }

    private static void dumpViewHierarchy(ViewGroup group, BufferedWriter out, int level) {
        if (!dumpView(group, out, level)) {
            return;
        }

        final int count = group.getChildCount();
        for (int i = 0; i < count; i++) {
            final View view = group.getChildAt(i);
            if (view instanceof ViewGroup) {
                dumpViewHierarchy((ViewGroup) view, out, level + 1);
            } else {
                dumpView(view, out, level + 1);
            }
        }
    }

    private static boolean dumpView(Object view, BufferedWriter out, int level) {
        try {
            for (int i = 0; i < level; i++) {
                out.write(' ');
            }
            out.write(view.getClass().getName());
            out.write('@');
            out.write(Integer.toHexString(view.hashCode()));
            out.newLine();
        } catch (IOException e) {
            Log.w("View", "Error while dumping hierarchy tree");
            return false;
        }
        return true;
    }

    private static Field[] capturedViewGetPropertyFields(Class<?> klass) {
        if (mCapturedViewFieldsForClasses == null) {
            mCapturedViewFieldsForClasses = new HashMap<Class<?>, Field[]>();
        }
        final HashMap<Class<?>, Field[]> map = mCapturedViewFieldsForClasses;

        Field[] fields = map.get(klass);
        if (fields != null) {
            return fields;
        }

        final ArrayList<Field> foundFields = new ArrayList<Field>();
        fields = klass.getFields();

        int count = fields.length;
        for (int i = 0; i < count; i++) {
            final Field field = fields[i];
            if (field.isAnnotationPresent(CapturedViewProperty.class)) {
                field.setAccessible(true);
                foundFields.add(field);
            }
        }

        fields = foundFields.toArray(new Field[foundFields.size()]);
        map.put(klass, fields);

        return fields;
    }

    private static Method[] capturedViewGetPropertyMethods(Class<?> klass) {
        if (mCapturedViewMethodsForClasses == null) {
            mCapturedViewMethodsForClasses = new HashMap<Class<?>, Method[]>();
        }
        final HashMap<Class<?>, Method[]> map = mCapturedViewMethodsForClasses;

        Method[] methods = map.get(klass);
        if (methods != null) {
            return methods;
        }

        final ArrayList<Method> foundMethods = new ArrayList<Method>();
        methods = klass.getMethods();

        int count = methods.length;
        for (int i = 0; i < count; i++) {
            final Method method = methods[i];
            if (method.getParameterTypes().length == 0 &&
                    method.isAnnotationPresent(CapturedViewProperty.class) &&
                    method.getReturnType() != Void.class) {
                method.setAccessible(true);
                foundMethods.add(method);
            }
        }

        methods = foundMethods.toArray(new Method[foundMethods.size()]);
        map.put(klass, methods);

        return methods;
    }

    private static String capturedViewExportMethods(Object obj, Class<?> klass,
            String prefix) {

        if (obj == null) {
            return "null";
        }

        StringBuilder sb = new StringBuilder();
        final Method[] methods = capturedViewGetPropertyMethods(klass);

        int count = methods.length;
        for (int i = 0; i < count; i++) {
            final Method method = methods[i];
            try {
                Object methodValue = method.invoke(obj, (Object[]) null);
                final Class<?> returnType = method.getReturnType();

                CapturedViewProperty property = method.getAnnotation(CapturedViewProperty.class);
                if (property.retrieveReturn()) {
                    //we are interested in the second level data only
                    sb.append(capturedViewExportMethods(methodValue, returnType, method.getName() + "#"));
                } else {
                    sb.append(prefix);
                    sb.append(method.getName());
                    sb.append("()=");

                    if (methodValue != null) {
                        final String value = methodValue.toString().replace("\n", "\\n");
                        sb.append(value);
                    } else {
                        sb.append("null");
                    }
                    sb.append("; ");
                }
              } catch (IllegalAccessException e) {
                  //Exception IllegalAccess, it is OK here
                  //we simply ignore this method
              } catch (InvocationTargetException e) {
                  //Exception InvocationTarget, it is OK here
                  //we simply ignore this method
              }
        }
        return sb.toString();
    }

    private static String capturedViewExportFields(Object obj, Class<?> klass, String prefix) {

        if (obj == null) {
            return "null";
        }

        StringBuilder sb = new StringBuilder();
        final Field[] fields = capturedViewGetPropertyFields(klass);

        int count = fields.length;
        for (int i = 0; i < count; i++) {
            final Field field = fields[i];
            try {
                Object fieldValue = field.get(obj);

                sb.append(prefix);
                sb.append(field.getName());
                sb.append("=");

                if (fieldValue != null) {
                    final String value = fieldValue.toString().replace("\n", "\\n");
                    sb.append(value);
                } else {
                    sb.append("null");
                }
                sb.append(' ');
            } catch (IllegalAccessException e) {
                //Exception IllegalAccess, it is OK here
                //we simply ignore this field
            }
        }
        return sb.toString();
    }

    /**
     * Dump view info for id based instrument test generation
     * (and possibly further data analysis). The results are dumped
     * to the log.
     * @param tag for log
     * @param view for dump
     */
    public static void dumpCapturedView(String tag, Object view) {
        Class<?> klass = view.getClass();
        StringBuilder sb = new StringBuilder(klass.getName() + ": ");
        sb.append(capturedViewExportFields(view, klass, ""));
        sb.append(capturedViewExportMethods(view, klass, ""));
        Log.d(tag, sb.toString());
    }
}