/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 java.io;
import java.nio.channels.FileChannel;
import org.apache.harmony.luni.platform.IFileSystem;
import org.apache.harmony.luni.platform.Platform;
import org.apache.harmony.luni.util.Msg;
import org.apache.harmony.nio.FileChannelFactory;
/**
* A specialized {@link InputStream} that reads from a file in the file system.
* All read requests made by calling methods in this class are directly
* forwarded to the equivalent function of the underlying operating system.
* Since this may induce some performance penalty, in particular if many small
* read requests are made, a FileInputStream is often wrapped by a
* BufferedInputStream.
*
* @see BufferedInputStream
* @see FileOutputStream
*
* @since Android 1.0
*/
public class FileInputStream extends InputStream implements Closeable {
/**
* The {@link FileDescriptor} representing this {@code FileInputStream}.
*/
FileDescriptor fd;
// The unique file channel associated with this FileInputStream (lazily
// initialized).
private FileChannel channel;
boolean innerFD;
private IFileSystem fileSystem = Platform.getFileSystem();
private static class RepositioningLock {
}
private Object repositioningLock = new RepositioningLock();
/**
* Constructs a new {@code FileInputStream} based on {@code file}.
*
* @param file
* the file from which this stream reads.
* @throws FileNotFoundException
* if {@code file} does not exist.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies the
* read request.
* @since Android 1.0
*/
public FileInputStream(File file) throws FileNotFoundException {
super();
SecurityManager security = System.getSecurityManager();
if (security != null) {
String filePath = (null == file ? null : file.getPath());
security.checkRead(filePath);
}
fd = new FileDescriptor();
fd.readOnly = true;
fd.descriptor = fileSystem.open(file.properPath(true),
IFileSystem.O_RDONLY);
innerFD = true;
// BEGIN android-removed
// channel = FileChannelFactory.getFileChannel(this, fd.descriptor,
// IFileSystem.O_RDONLY);
// END android-removed
}
/**
* Constructs a new {@code FileInputStream} on the {@link FileDescriptor}
* {@code fd}. The file must already be open, therefore no
* {@code FileNotFoundException} will be thrown.
*
* @param fd
* the FileDescriptor from which this stream reads.
* @throws NullPointerException
* if {@code fd} is {@code null}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies the
* read request.
* @since Android 1.0
*/
public FileInputStream(FileDescriptor fd) {
super();
if (fd == null) {
throw new NullPointerException();
}
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(fd);
}
this.fd = fd;
innerFD = false;
// BEGIN android-removed
// channel = FileChannelFactory.getFileChannel(this, fd.descriptor,
// IFileSystem.O_RDONLY);
// END android-removed
}
/**
* Constructs a new {@code FileInputStream} on the file named
* {@code fileName}. The path of {@code fileName} may be absolute or
* relative to the system property {@code "user.dir"}.
*
* @param fileName
* the path and name of the file from which this stream reads.
* @throws FileNotFoundException
* if there is no file named {@code fileName}.
* @throws SecurityException
* if a {@code SecurityManager} is installed and it denies the
* read request.
* @since Android 1.0
*/
public FileInputStream(String fileName) throws FileNotFoundException {
this(null == fileName ? (File) null : new File(fileName));
}
/**
* Returns the number of bytes that are available before this stream will
* block. This method always returns the size of the file minus the current
* position.
*
* @return the number of bytes available before blocking.
* @throws IOException
* if an error occurs in this stream.
* @since Android 1.0
*/
@Override
public int available() throws IOException {
openCheck();
// BEGIN android-added
// Android always uses the ioctl() method of determining bytes
// available. See the long discussion in
// org_apache_harmony_luni_platform_OSFileSystem.cpp about its
// use.
return fileSystem.ioctlAvailable(fd.descriptor);
// END android-added
// BEGIN android-deleted
// synchronized (repositioningLock) {
// // stdin requires special handling
// if (fd == FileDescriptor.in) {
// return (int) fileSystem.ttyAvailable();
// }
//
// long currentPosition = fileSystem.seek(fd.descriptor, 0L,
// IFileSystem.SEEK_CUR);
// long endOfFilePosition = fileSystem.seek(fd.descriptor, 0L,
// IFileSystem.SEEK_END);
// fileSystem.seek(fd.descriptor, currentPosition,
// IFileSystem.SEEK_SET);
// return (int) (endOfFilePosition - currentPosition);
// }
// END android-deleted
}
/**
* Closes this stream.
*
* @throws IOException
* if an error occurs attempting to close this stream.
* @since Android 1.0
*/
@Override
public void close() throws IOException {
// BEGIN android-changed
synchronized (this) {
if (channel != null && channel.isOpen()) {
channel.close();
channel = null;
}
if (fd != null && fd.descriptor >= 0 && innerFD) {
fileSystem.close(fd.descriptor);
fd.descriptor = -1;
}
}
// END android-changed
}
/**
* Ensures that all resources for this stream are released when it is about
* to be garbage collected.
*
* @throws IOException
* if an error occurs attempting to finalize this stream.
* @since Android 1.0
*/
@Override
protected void finalize() throws IOException {
close();
}
/**
* Returns the {@link FileChannel} equivalent to this input stream.
* <p>
* The file channel is read-only and has an initial position within the file
* that is the same as the current position of this stream within the file.
* All changes made to the underlying file descriptor state via the channel
* are visible by the input stream and vice versa.
* </p>
*
* @return the file channel for this stream.
* @since Android 1.0
*/
public FileChannel getChannel() {
// BEGIN android-changed
synchronized(this) {
if (channel == null) {
channel = FileChannelFactory.getFileChannel(this, fd.descriptor,
IFileSystem.O_RDONLY);
}
return channel;
}
// END android-changed
}
/**
* Returns the {@link FileDescriptor} representing the operating system
* resource for this stream.
*
* @return the {@code FileDescriptor} for this stream.
* @throws IOException
* if an error occurs while getting this stream's
* {@code FileDescriptor}.
* @since Android 1.0
*/
public final FileDescriptor getFD() throws IOException {
return fd;
}
/**
* Reads a single byte from this stream and returns it as an integer in the
* range from 0 to 255. Returns -1 if the end of this stream has been
* reached.
*
* @return the byte read or -1 if the end of this stream has been reached.
* @throws IOException
* if this stream is closed or another I/O error occurs.
* @since Android 1.0
*/
@Override
public int read() throws IOException {
byte[] readed = new byte[1];
int result = read(readed, 0, 1);
return result == -1 ? -1 : readed[0] & 0xff;
}
/**
* Reads bytes from this stream and stores them in the byte array
* {@code buffer}.
*
* @param buffer
* the byte array in which to store the bytes read.
* @return the number of bytes actually read or -1 if the end of the stream
* has been reached.
* @throws IOException
* if this stream is closed or another I/O error occurs.
* @since Android 1.0
*/
@Override
public int read(byte[] buffer) throws IOException {
return read(buffer, 0, buffer.length);
}
/**
* Reads at most {@code count} bytes from this stream and stores them in the
* byte array {@code buffer} starting at {@code offset}.
*
* @param buffer
* the byte array in which to store the bytes read.
* @param offset
* the initial position in {@code buffer} to store the bytes read
* from this stream.
* @param count
* the maximum number of bytes to store in {@code buffer}.
* @return the number of bytes actually read or -1 if the end of the stream
* has been reached.
* @throws IndexOutOfBoundsException
* if {@code offset < 0} or {@code count < 0}, or if
* {@code offset + count} is greater than the size of
* {@code buffer}.
* @throws IOException
* if the stream is closed or another IOException occurs.
* @since Android 1.0
*/
@Override
public int read(byte[] buffer, int offset, int count) throws IOException {
// BEGIN android-changed
// Exception priorities (in case of multiple errors) differ from
// RI, but are spec-compliant.
// made implicit null check explicit,
// used (offset | count) < 0 instead of (offset < 0) || (count < 0)
// to safe one operation
if (buffer == null) {
throw new NullPointerException(Msg.getString("K0047")); //$NON-NLS-1$
}
if ((count | offset) < 0 || count > buffer.length - offset) {
throw new IndexOutOfBoundsException(Msg.getString("K002f")); //$NON-NLS-1$
}
// END android-changed
if (0 == count) {
return 0;
}
openCheck();
synchronized (repositioningLock) {
// stdin requires special handling
if (fd == FileDescriptor.in) {
return (int) fileSystem.ttyRead(buffer, offset, count);
}
return (int) fileSystem.read(fd.descriptor, buffer, offset, count);
}
}
/**
* Skips {@code count} number of bytes in this stream. Subsequent
* {@code read()}'s will not return these bytes unless {@code reset()} is
* used. This method may perform multiple reads to read {@code count} bytes.
*
* @param count
* the number of bytes to skip.
* @return the number of bytes actually skipped.
* @throws IOException
* if {@code count < 0}, this stream is closed or another
* IOException occurs.
* @since Android 1.0
*/
@Override
public long skip(long count) throws IOException {
openCheck();
if (count == 0) {
return 0;
}
if (count < 0) {
// KA013=Number of bytes to skip cannot be negative
throw new IOException(Msg.getString("KA013")); //$NON-NLS-1$
}
// stdin requires special handling
if (fd == FileDescriptor.in) {
// Read and discard count bytes in 8k chunks
long skipped = 0, numRead;
int chunk = count < 8192 ? (int) count : 8192;
byte[] buffer = new byte[chunk];
for (long i = count / chunk; i >= 0; i--) {
numRead = fileSystem.ttyRead(buffer, 0, chunk);
skipped += numRead;
if (numRead < chunk) {
return skipped;
}
}
return skipped;
}
synchronized (repositioningLock) {
final long currentPosition = fileSystem.seek(fd.descriptor, 0L,
IFileSystem.SEEK_CUR);
final long newPosition = fileSystem.seek(fd.descriptor,
currentPosition + count, IFileSystem.SEEK_SET);
return newPosition - currentPosition;
}
}
private synchronized void openCheck() throws IOException {
if (fd.descriptor < 0) {
throw new IOException();
}
}
}
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