Merge "Revert "Have AssetFileDescriptor.AutoCloseInputStream use pread"" into... (96fc0a49) · Commits · e / os / android_frameworks_base

core/java/android/content/res/AssetFileDescriptor.java

+33 −201

Original line number	Original line	Diff line number	Diff line
	@@ -21,20 +21,12 @@ import android.os.Bundle;
	import android.os.Parcel;		import android.os.Parcel;
	import android.os.ParcelFileDescriptor;		import android.os.ParcelFileDescriptor;
	import android.os.Parcelable;		import android.os.Parcelable;
	import android.system.ErrnoException;
	import android.system.Os;

	import java.io.Closeable;		import java.io.Closeable;
	import java.io.FileDescriptor;		import java.io.FileDescriptor;
	import java.io.FileInputStream;		import java.io.FileInputStream;
	import java.io.FileOutputStream;		import java.io.FileOutputStream;
	import java.io.IOException;		import java.io.IOException;
	import java.nio.ByteBuffer;
	import java.nio.MappedByteBuffer;
	import java.nio.channels.FileChannel;
	import java.nio.channels.FileLock;
	import java.nio.channels.ReadableByteChannel;
	import java.nio.channels.WritableByteChannel;

	/**		/**
	* File descriptor of an entry in the AssetManager. This provides your own		* File descriptor of an entry in the AssetManager. This provides your own
	@@ -211,26 +203,19 @@ public class AssetFileDescriptor implements Parcelable, Closeable {
	*/		*/
	public static class AutoCloseInputStream		public static class AutoCloseInputStream
	extends ParcelFileDescriptor.AutoCloseInputStream {		extends ParcelFileDescriptor.AutoCloseInputStream {
	/** Size of current file. */		private long mRemaining;
	private long mTotalSize;
	/** The absolute position of current file start point. */
	private final long mFileOffset;
	/** The relative position where input stream is against mFileOffset. */
	private long mOffset;
	private OffsetCorrectFileChannel mOffsetCorrectFileChannel;

	public AutoCloseInputStream(AssetFileDescriptor fd) throws IOException {		public AutoCloseInputStream(AssetFileDescriptor fd) throws IOException {
	super(fd.getParcelFileDescriptor());		super(fd.getParcelFileDescriptor());
	mTotalSize = fd.getLength();		super.skip(fd.getStartOffset());
	mFileOffset = fd.getStartOffset();		mRemaining = (int) fd.getLength();
	}		}

	@Override		@Override
	public int available() throws IOException {		public int available() throws IOException {
	long available = mTotalSize - mOffset;		return mRemaining >= 0
	return available >= 0		? (mRemaining < 0x7fffffff ? (int) mRemaining : 0x7fffffff)
	? (available < 0x7fffffff ? (int) available : 0x7fffffff)		: super.available();
	: 0;
	}		}

	@Override		@Override
	@@ -242,24 +227,15 @@ public class AssetFileDescriptor implements Parcelable, Closeable {

	@Override		@Override
	public int read(byte[] buffer, int offset, int count) throws IOException {		public int read(byte[] buffer, int offset, int count) throws IOException {
	int available = available();		if (mRemaining >= 0) {
	if (available <= 0) {		if (mRemaining == 0) return -1;
	return -1;		if (count > mRemaining) count = (int) mRemaining;
	}		int res = super.read(buffer, offset, count);
			if (res >= 0) mRemaining -= res;
	if (count > available) count = available;
	try {
	int res = Os.pread(getFD(), buffer, offset, count, mFileOffset + mOffset);
	// pread returns 0 at end of file, while java's InputStream interface requires -1
	if (res == 0) res = -1;
	if (res > 0) {
	mOffset += res;
	updateChannelPosition(mOffset + mFileOffset);
	}
	return res;		return res;
	} catch (ErrnoException e) {
	throw new IOException(e);
	}		}

			return super.read(buffer, offset, count);
	}		}

	@Override		@Override
	@@ -269,185 +245,41 @@ public class AssetFileDescriptor implements Parcelable, Closeable {

	@Override		@Override
	public long skip(long count) throws IOException {		public long skip(long count) throws IOException {
	int available = available();		if (mRemaining >= 0) {
	if (available <= 0) {		if (mRemaining == 0) return -1;
	return -1;		if (count > mRemaining) count = mRemaining;
			long res = super.skip(count);
			if (res >= 0) mRemaining -= res;
			return res;
	}		}

	if (count > available) count = available;		return super.skip(count);
	mOffset += count;
	updateChannelPosition(mOffset + mFileOffset);
	return count;
	}		}

	@Override		@Override
	public void mark(int readlimit) {		public void mark(int readlimit) {
			if (mRemaining >= 0) {
	// Not supported.		// Not supported.
	return;		return;
	}		}
			super.mark(readlimit);
			}

	@Override		@Override
	public boolean markSupported() {		public boolean markSupported() {
			if (mRemaining >= 0) {
	return false;		return false;
	}		}
			return super.markSupported();
			}

	@Override		@Override
	public synchronized void reset() throws IOException {		public synchronized void reset() throws IOException {
			if (mRemaining >= 0) {
	// Not supported.		// Not supported.
	return;		return;
	}		}
			super.reset();
	@Override
	public FileChannel getChannel() {
	if (mOffsetCorrectFileChannel == null) {
	mOffsetCorrectFileChannel = new OffsetCorrectFileChannel(super.getChannel());
	}
	try {
	updateChannelPosition(mOffset + mFileOffset);
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	return mOffsetCorrectFileChannel;
	}

	/**
	* Update the position of mOffsetCorrectFileChannel only after it is constructed.
	*
	* @param newPosition The absolute position mOffsetCorrectFileChannel needs to be moved to.
	*/
	private void updateChannelPosition(long newPosition) throws IOException {
	if (mOffsetCorrectFileChannel != null) {
	mOffsetCorrectFileChannel.position(newPosition);
	}
	}

	/**
	* A FileChannel wrapper that will update mOffset of the AutoCloseInputStream
	* to correct position when using FileChannel to read. All occurrence of position
	* should be using absolute solution and each override method just do Delegation
	* besides additional check. All methods related to write mode have been disabled
	* and will throw UnsupportedOperationException with customized message.
	*/
	private class OffsetCorrectFileChannel extends FileChannel {
	private final FileChannel mDelegate;
	private static final String METHOD_NOT_SUPPORTED_MESSAGE =
	"This Method is not supported in AutoCloseInputStream FileChannel.";

	OffsetCorrectFileChannel(FileChannel fc) {
	mDelegate = fc;
	}

	@Override
	public int read(ByteBuffer dst) throws IOException {
	if (available() <= 0) return -1;
	int bytesRead = mDelegate.read(dst);
	if (bytesRead != -1) mOffset += bytesRead;
	return bytesRead;
	}

	@Override
	public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
	if (available() <= 0) return -1;
	if (mOffset + length > mTotalSize) {
	length = (int) (mTotalSize - mOffset);
	}
	long bytesRead = mDelegate.read(dsts, offset, length);
	if (bytesRead != -1) mOffset += bytesRead;
	return bytesRead;
	}

	@Override
	/*The only read method that does not move channel position/
	public int read(ByteBuffer dst, long position) throws IOException {
	if (position - mFileOffset > mTotalSize) return -1;
	return mDelegate.read(dst, position);
	}

	@Override
	public long position() throws IOException {
	return mDelegate.position();
	}

	@Override
	public FileChannel position(long newPosition) throws IOException {
	mOffset = newPosition - mFileOffset;
	return mDelegate.position(newPosition);
	}

	@Override
	public long size() throws IOException {
	return mTotalSize;
	}

	@Override
	public long transferTo(long position, long count, WritableByteChannel target)
	throws IOException {
	if (position - mFileOffset > mTotalSize) {
	return 0;
	}
	if (position - mFileOffset + count > mTotalSize) {
	count = mTotalSize - (position - mFileOffset);
	}
	return mDelegate.transferTo(position, count, target);
	}

	@Override
	public MappedByteBuffer map(MapMode mode, long position, long size) throws IOException {
	if (position - mFileOffset > mTotalSize) {
	throw new IOException(
	"Cannot map to buffer because position exceed current file size.");
	}
	if (position - mFileOffset + size > mTotalSize) {
	size = mTotalSize - (position - mFileOffset);
	}
	return mDelegate.map(mode, position, size);
	}

	@Override
	protected void implCloseChannel() throws IOException {
	mDelegate.close();
	}

	@Override
	public int write(ByteBuffer src) throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}

	@Override
	public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}

	@Override
	public int write(ByteBuffer src, long position) throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}

	@Override
	public long transferFrom(ReadableByteChannel src, long position, long count)
	throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}

	@Override
	public FileChannel truncate(long size) throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}

	@Override
	public void force(boolean metaData) throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}

	@Override
	public FileLock lock(long position, long size, boolean shared) throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}

	@Override
	public FileLock tryLock(long position, long size, boolean shared) throws IOException {
	throw new UnsupportedOperationException(METHOD_NOT_SUPPORTED_MESSAGE);
	}
	}		}
	}		}