Merge "Revert "Have AssetFileDescriptor.AutoCloseInputStream use pread"" into udc-dev
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TreeHugger Robot
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Android (Google) Code Review
Android (Google) Code Review
commit
138683c165
@@ -21,20 +21,12 @@ import android.os.Bundle;
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import android.os.Parcel;
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import android.os.ParcelFileDescriptor;
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import android.os.Parcelable;
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import android.system.ErrnoException;
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import android.system.Os;
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import java.io.Closeable;
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import java.io.FileDescriptor;
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import java.io.FileInputStream;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.nio.MappedByteBuffer;
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import java.nio.channels.FileChannel;
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import java.nio.channels.FileLock;
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import java.nio.channels.ReadableByteChannel;
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import java.nio.channels.WritableByteChannel;
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/**
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* File descriptor of an entry in the AssetManager. This provides your own
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@@ -211,26 +203,19 @@ public class AssetFileDescriptor implements Parcelable, Closeable {
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*/
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public static class AutoCloseInputStream
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extends ParcelFileDescriptor.AutoCloseInputStream {
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/** Size of current file. */
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private long mTotalSize;
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/** The absolute position of current file start point. */
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private final long mFileOffset;
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/** The relative position where input stream is against mFileOffset. */
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private long mOffset;
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private OffsetCorrectFileChannel mOffsetCorrectFileChannel;
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private long mRemaining;
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public AutoCloseInputStream(AssetFileDescriptor fd) throws IOException {
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super(fd.getParcelFileDescriptor());
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mTotalSize = fd.getLength();
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mFileOffset = fd.getStartOffset();
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super.skip(fd.getStartOffset());
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mRemaining = (int) fd.getLength();
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}
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@Override
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public int available() throws IOException {
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long available = mTotalSize - mOffset;
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return available >= 0
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? (available < 0x7fffffff ? (int) available : 0x7fffffff)
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: 0;
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return mRemaining >= 0
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? (mRemaining < 0x7fffffff ? (int) mRemaining : 0x7fffffff)
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: super.available();
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}
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@Override
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@@ -242,24 +227,15 @@ public class AssetFileDescriptor implements Parcelable, Closeable {
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@Override
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public int read(byte[] buffer, int offset, int count) throws IOException {
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int available = available();
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if (available <= 0) {
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return -1;
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if (mRemaining >= 0) {
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if (mRemaining == 0) return -1;
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if (count > mRemaining) count = (int) mRemaining;
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int res = super.read(buffer, offset, count);
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if (res >= 0) mRemaining -= res;
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return res;
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}
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if (count > available) count = available;
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try {
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int res = Os.pread(getFD(), buffer, offset, count, mFileOffset + mOffset);
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// pread returns 0 at end of file, while java's InputStream interface requires -1
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if (res == 0) res = -1;
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if (res > 0) {
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mOffset += res;
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updateChannelPosition(mOffset + mFileOffset);
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}
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return res;
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} catch (ErrnoException e) {
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throw new IOException(e);
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}
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return super.read(buffer, offset, count);
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}
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@Override
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@@ -269,185 +245,41 @@ public class AssetFileDescriptor implements Parcelable, Closeable {
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@Override
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public long skip(long count) throws IOException {
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int available = available();
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if (available <= 0) {
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return -1;
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if (mRemaining >= 0) {
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if (mRemaining == 0) return -1;
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if (count > mRemaining) count = mRemaining;
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long res = super.skip(count);
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if (res >= 0) mRemaining -= res;
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return res;
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}
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if (count > available) count = available;
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mOffset += count;
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updateChannelPosition(mOffset + mFileOffset);
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return count;
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return super.skip(count);
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}
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@Override
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public void mark(int readlimit) {
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// Not supported.
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return;
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if (mRemaining >= 0) {
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// Not supported.
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return;
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}
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super.mark(readlimit);
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}
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@Override
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public boolean markSupported() {
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return false;
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if (mRemaining >= 0) {
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return false;
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}
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return super.markSupported();
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}
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@Override
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public synchronized void reset() throws IOException {
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// Not supported.
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return;
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}
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@Override
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public FileChannel getChannel() {
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if (mOffsetCorrectFileChannel == null) {
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mOffsetCorrectFileChannel = new OffsetCorrectFileChannel(super.getChannel());
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}
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try {
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updateChannelPosition(mOffset + mFileOffset);
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} catch (IOException e) {
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throw new RuntimeException(e);
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}
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return mOffsetCorrectFileChannel;
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}
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/**
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* Update the position of mOffsetCorrectFileChannel only after it is constructed.
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*
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* @param newPosition The absolute position mOffsetCorrectFileChannel needs to be moved to.
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*/
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private void updateChannelPosition(long newPosition) throws IOException {
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if (mOffsetCorrectFileChannel != null) {
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mOffsetCorrectFileChannel.position(newPosition);
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}
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}
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/**
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* A FileChannel wrapper that will update mOffset of the AutoCloseInputStream
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* to correct position when using FileChannel to read. All occurrence of position
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* should be using absolute solution and each override method just do Delegation
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* besides additional check. All methods related to write mode have been disabled
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* and will throw UnsupportedOperationException with customized message.
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*/
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private class OffsetCorrectFileChannel extends FileChannel {
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private final FileChannel mDelegate;
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private static final String METHOD_NOT_SUPPORTED_MESSAGE =
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"This Method is not supported in AutoCloseInputStream FileChannel.";
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OffsetCorrectFileChannel(FileChannel fc) {
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mDelegate = fc;
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}
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@Override
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public int read(ByteBuffer dst) throws IOException {
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if (available() <= 0) return -1;
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int bytesRead = mDelegate.read(dst);
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if (bytesRead != -1) mOffset += bytesRead;
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return bytesRead;
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}
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@Override
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public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
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if (available() <= 0) return -1;
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if (mOffset + length > mTotalSize) {
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length = (int) (mTotalSize - mOffset);
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}
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long bytesRead = mDelegate.read(dsts, offset, length);
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if (bytesRead != -1) mOffset += bytesRead;
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return bytesRead;
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}
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@Override
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/**The only read method that does not move channel position*/
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public int read(ByteBuffer dst, long position) throws IOException {
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if (position - mFileOffset > mTotalSize) return -1;
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return mDelegate.read(dst, position);
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}
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@Override
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public long position() throws IOException {
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return mDelegate.position();
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}
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@Override
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public FileChannel position(long newPosition) throws IOException {
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mOffset = newPosition - mFileOffset;
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return mDelegate.position(newPosition);
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}
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@Override
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public long size() throws IOException {
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return mTotalSize;
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}
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@Override
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public long transferTo(long position, long count, WritableByteChannel target)
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throws IOException {
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if (position - mFileOffset > mTotalSize) {
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return 0;
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}
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if (position - mFileOffset + count > mTotalSize) {
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count = mTotalSize - (position - mFileOffset);
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}
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return mDelegate.transferTo(position, count, target);
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}
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@Override
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public MappedByteBuffer map(MapMode mode, long position, long size) throws IOException {
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if (position - mFileOffset > mTotalSize) {
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throw new IOException(
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"Cannot map to buffer because position exceed current file size.");
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}
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if (position - mFileOffset + size > mTotalSize) {
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size = mTotalSize - (position - mFileOffset);
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}
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return mDelegate.map(mode, position, size);
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}
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@Override
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protected void implCloseChannel() throws IOException {
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mDelegate.close();
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}
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@Override
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public int write(ByteBuffer src) throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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}
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@Override
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public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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}
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@Override
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public int write(ByteBuffer src, long position) throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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}
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@Override
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public long transferFrom(ReadableByteChannel src, long position, long count)
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throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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}
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@Override
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public FileChannel truncate(long size) throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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}
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@Override
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public void force(boolean metaData) throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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}
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@Override
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public FileLock lock(long position, long size, boolean shared) throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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}
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@Override
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public FileLock tryLock(long position, long size, boolean shared) throws IOException {
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throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
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if (mRemaining >= 0) {
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// Not supported.
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return;
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}
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super.reset();
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}
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}
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