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/*
* Copyright (C) 2014 The Android Open Source Project
* Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.io;
import static android.system.OsConstants.O_RDONLY;
import java.nio.channels.FileChannel;
import dalvik.annotation.optimization.ReachabilitySensitive;
import dalvik.system.BlockGuard;
import dalvik.system.CloseGuard;
import sun.nio.ch.FileChannelImpl;
import libcore.io.IoBridge;
import libcore.io.IoTracker;
import libcore.io.IoUtils;
/**
* A FileInputStream obtains input bytes
* from a file in a file system. What files
* are available depends on the host environment.
*
* FileInputStream is meant for reading streams of raw bytes
* such as image data. For reading streams of characters, consider using
* FileReader.
*
* @author Arthur van Hoff
* @see java.io.File
* @see java.io.FileDescriptor
* @see java.io.FileOutputStream
* @see java.nio.file.Files#newInputStream
* @since JDK1.0
*/
public
class FileInputStream extends InputStream
{
/* File Descriptor - handle to the open file */
// Android-added: @ReachabilitySensitive
@ReachabilitySensitive
private final FileDescriptor fd;
/**
* The path of the referenced file
* (null if the stream is created with a file descriptor)
*/
private final String path;
private FileChannel channel = null;
private final Object closeLock = new Object();
private volatile boolean closed = false;
// Android-added: Field for tracking whether the stream owns the underlying FileDescriptor.
private final boolean isFdOwner;
// Android-added: CloseGuard support.
@ReachabilitySensitive
private final CloseGuard guard = CloseGuard.get();
// Android-added: Tracking of unbuffered I/O.
private final IoTracker tracker = new IoTracker();
/**
* Creates a FileInputStream by
* opening a connection to an actual file,
* the file named by the path name name
* in the file system. A new FileDescriptor
* object is created to represent this file
* connection.
*
* First, if there is a security
* manager, its checkRead method
* is called with the name argument
* as its argument.
*
* If the named file does not exist, is a directory rather than a regular
* file, or for some other reason cannot be opened for reading then a
* FileNotFoundException is thrown.
*
* @param name the system-dependent file name.
* @exception FileNotFoundException if the file does not exist,
* is a directory rather than a regular file,
* or for some other reason cannot be opened for
* reading.
* @exception SecurityException if a security manager exists and its
* checkRead method denies read access
* to the file.
* @see java.lang.SecurityManager#checkRead(java.lang.String)
*/
public FileInputStream(String name) throws FileNotFoundException {
this(name != null ? new File(name) : null);
}
/**
* Creates a FileInputStream by
* opening a connection to an actual file,
* the file named by the File
* object file in the file system.
* A new FileDescriptor object
* is created to represent this file connection.
*
* First, if there is a security manager,
* its checkRead method is called
* with the path represented by the file
* argument as its argument.
*
* If the named file does not exist, is a directory rather than a regular
* file, or for some other reason cannot be opened for reading then a
* FileNotFoundException is thrown.
*
* @param file the file to be opened for reading.
* @exception FileNotFoundException if the file does not exist,
* is a directory rather than a regular file,
* or for some other reason cannot be opened for
* reading.
* @exception SecurityException if a security manager exists and its
* checkRead method denies read access to the file.
* @see java.io.File#getPath()
* @see java.lang.SecurityManager#checkRead(java.lang.String)
*/
public FileInputStream(File file) throws FileNotFoundException {
String name = (file != null ? file.getPath() : null);
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(name);
}
if (name == null) {
throw new NullPointerException();
}
if (file.isInvalid()) {
throw new FileNotFoundException("Invalid file path");
}
// BEGIN Android-changed: Open files using IoBridge to share BlockGuard & StrictMode logic.
// http://b/112107427
// fd = new FileDescriptor();
fd = IoBridge.open(name, O_RDONLY);
// END Android-changed: Open files using IoBridge to share BlockGuard & StrictMode logic.
// Android-changed: Tracking mechanism for FileDescriptor sharing.
// fd.attach(this);
isFdOwner = true;
path = name;
// Android-removed: Open files using IoBridge to share BlockGuard & StrictMode logic.
// open(name);
// Android-added: File descriptor ownership tracking.
IoUtils.setFdOwner(this.fd, this);
// Android-added: CloseGuard support.
guard.open("close");
}
// Android-removed: Documentation around SecurityException. Not thrown on Android.
/**
* Creates a FileInputStream by using the file descriptor
* fdObj, which represents an existing connection to an
* actual file in the file system.
*
* If there is a security manager, its checkRead method is
* called with the file descriptor fdObj as its argument to
* see if it's ok to read the file descriptor. If read access is denied
* to the file descriptor a SecurityException is thrown.
*
* If fdObj is null then a NullPointerException
* is thrown.
*
* This constructor does not throw an exception if fdObj
* is {@link java.io.FileDescriptor#valid() invalid}.
* However, if the methods are invoked on the resulting stream to attempt
* I/O on the stream, an IOException is thrown.
*
* @param fdObj the file descriptor to be opened for reading.
*/
public FileInputStream(FileDescriptor fdObj) {
// Android-changed: Delegate to added hidden constructor.
this(fdObj, false /* isFdOwner */);
}
// Android-added: Internal/hidden constructor for specifying FileDescriptor ownership.
// Android-removed: SecurityManager calls.
/** @hide */
public FileInputStream(FileDescriptor fdObj, boolean isFdOwner) {
if (fdObj == null) {
// Android-changed: Improved NullPointerException message.
throw new NullPointerException("fdObj == null");
}
fd = fdObj;
path = null;
// Android-changed: FileDescriptor ownership tracking mechanism.
/*
/*
* FileDescriptor is being shared by streams.
* Register this stream with FileDescriptor tracker.
*
fd.attach(this);
*/
this.isFdOwner = isFdOwner;
if (isFdOwner) {
IoUtils.setFdOwner(this.fd, this);
}
}
// BEGIN Android-changed: Open files using IoBridge to share BlockGuard & StrictMode logic.
// http://b/112107427
/*
/**
* Opens the specified file for reading.
* @param name the name of the file
*
private native void open0(String name) throws FileNotFoundException;
// wrap native call to allow instrumentation
/**
* Opens the specified file for reading.
* @param name the name of the file
*
private void open(String name) throws FileNotFoundException {
open0(name);
}
*/
// END Android-changed: Open files using IoBridge to share BlockGuard & StrictMode logic.
/**
* Reads a byte of data from this input stream. This method blocks
* if no input is yet available.
*
* @return the next byte of data, or -1 if the end of the
* file is reached.
* @exception IOException if an I/O error occurs.
*/
public int read() throws IOException {
// Android-changed: Read methods delegate to read(byte[], int, int) to share Android logic.
byte[] b = new byte[1];
return (read(b, 0, 1) != -1) ? b[0] & 0xff : -1;
}
// Android-removed: Read methods delegate to read(byte[], int, int) to share Android logic.
// private native int read0() throws IOException;
// Android-removed: Read methods delegate to read(byte[], int, int) to share Android logic.
/*
/**
* Reads a subarray as a sequence of bytes.
* @param b the data to be written
* @param off the start offset in the data
* @param len the number of bytes that are written
* @exception IOException If an I/O error has occurred.
*
private native int readBytes(byte b[], int off, int len) throws IOException;
*/
/**
* Reads up to b.length bytes of data from this input
* stream into an array of bytes. This method blocks until some input
* is available.
*
* @param b the buffer into which the data is read.
* @return the total number of bytes read into the buffer, or
* -1 if there is no more data because the end of
* the file has been reached.
* @exception IOException if an I/O error occurs.
*/
public int read(byte b[]) throws IOException {
// Android-changed: Read methods delegate to read(byte[], int, int) to share Android logic.
return read(b, 0, b.length);
}
/**
* Reads up to len bytes of data from this input stream
* into an array of bytes. If len is not zero, the method
* blocks until some input is available; otherwise, no
* bytes are read and 0 is returned.
*
* @param b the buffer into which the data is read.
* @param off the start offset in the destination array b
* @param len the maximum number of bytes read.
* @return the total number of bytes read into the buffer, or
* -1 if there is no more data because the end of
* the file has been reached.
* @exception NullPointerException If b is null.
* @exception IndexOutOfBoundsException If off is negative,
* len is negative, or len is greater than
* b.length - off
* @exception IOException if an I/O error occurs.
*/
public int read(byte b[], int off, int len) throws IOException {
// Android-added: close() check before I/O.
if (closed && len > 0) {
throw new IOException("Stream Closed");
}
// Android-added: Tracking of unbuffered I/O.
tracker.trackIo(len);
// Android-changed: Use IoBridge instead of calling native method.
return IoBridge.read(fd, b, off, len);
}
/**
* Skips over and discards n bytes of data from the
* input stream.
*
*
The skip method may, for a variety of
* reasons, end up skipping over some smaller number of bytes,
* possibly 0. If n is negative, the method
* will try to skip backwards. In case the backing file does not support
* backward skip at its current position, an IOException is
* thrown. The actual number of bytes skipped is returned. If it skips
* forwards, it returns a positive value. If it skips backwards, it
* returns a negative value.
*
*
This method may skip more bytes than what are remaining in the
* backing file. This produces no exception and the number of bytes skipped
* may include some number of bytes that were beyond the EOF of the
* backing file. Attempting to read from the stream after skipping past
* the end will result in -1 indicating the end of the file.
*
* @param n the number of bytes to be skipped.
* @return the actual number of bytes skipped.
* @exception IOException if n is negative, if the stream does not
* support seek, or if an I/O error occurs.
*/
// BEGIN Android-changed: skip(long) implementation changed from bare native.
public long skip(long n) throws IOException {
// Android-added: close() check before I/O.
if (closed) {
throw new IOException("Stream Closed");
}
try {
// Android-added: BlockGuard support.
BlockGuard.getThreadPolicy().onReadFromDisk();
return skip0(n);
} catch(UseManualSkipException e) {
return super.skip(n);
}
}
private native long skip0(long n) throws IOException, UseManualSkipException;
/*
* Used to force manual skip when FileInputStream operates on pipe
*/
private static class UseManualSkipException extends Exception {
}
// END Android-changed: skip(long) implementation changed from bare native.
/**
* Returns an estimate of the number of remaining bytes that can be read (or
* skipped over) from this input stream without blocking by the next
* invocation of a method for this input stream. Returns 0 when the file
* position is beyond EOF. The next invocation might be the same thread
* or another thread. A single read or skip of this many bytes will not
* block, but may read or skip fewer bytes.
*
*
In some cases, a non-blocking read (or skip) may appear to be
* blocked when it is merely slow, for example when reading large
* files over slow networks.
*
* @return an estimate of the number of remaining bytes that can be read
* (or skipped over) from this input stream without blocking.
* @exception IOException if this file input stream has been closed by calling
* {@code close} or an I/O error occurs.
*/
// BEGIN Android-changed: available() implementation changed from bare native.
public int available() throws IOException {
// Android-added: close() check before I/O.
if (closed) {
throw new IOException("Stream Closed");
}
return available0();
}
private native int available0() throws IOException;
// END Android-changed: available() implementation changed from bare native.
/**
* Closes this file input stream and releases any system resources
* associated with the stream.
*
*
If this stream has an associated channel then the channel is closed
* as well.
*
* @exception IOException if an I/O error occurs.
*
* @revised 1.4
* @spec JSR-51
*/
public void close() throws IOException {
synchronized (closeLock) {
if (closed) {
return;
}
closed = true;
}
// Android-added: CloseGuard support.
guard.close();
if (channel != null) {
channel.close();
}
// BEGIN Android-changed: Close handling / notification of blocked threads.
if (isFdOwner) {
IoBridge.closeAndSignalBlockedThreads(fd);
}
// END Android-changed: Close handling / notification of blocked threads.
}
/**
* Returns the FileDescriptor
* object that represents the connection to
* the actual file in the file system being
* used by this FileInputStream.
*
* @return the file descriptor object associated with this stream.
* @exception IOException if an I/O error occurs.
* @see java.io.FileDescriptor
*/
public final FileDescriptor getFD() throws IOException {
if (fd != null) {
return fd;
}
throw new IOException();
}
/**
* Returns the unique {@link java.nio.channels.FileChannel FileChannel}
* object associated with this file input stream.
*
*
The initial {@link java.nio.channels.FileChannel#position()
* position} of the returned channel will be equal to the
* number of bytes read from the file so far. Reading bytes from this
* stream will increment the channel's position. Changing the channel's
* position, either explicitly or by reading, will change this stream's
* file position.
*
* @return the file channel associated with this file input stream
*
* @since 1.4
* @spec JSR-51
*/
public FileChannel getChannel() {
synchronized (this) {
if (channel == null) {
channel = FileChannelImpl.open(fd, path, true, false, this);
}
return channel;
}
}
// BEGIN Android-removed: Unused code.
/*
private static native void initIDs();
private native void close0() throws IOException;
static {
initIDs();
}
*/
// END Android-removed: Unused code.
/**
* Ensures that the close method of this file input stream is
* called when there are no more references to it.
*
* @exception IOException if an I/O error occurs.
* @see java.io.FileInputStream#close()
*/
protected void finalize() throws IOException {
// Android-added: CloseGuard support.
if (guard != null) {
guard.warnIfOpen();
}
if ((fd != null) && (fd != FileDescriptor.in)) {
// Android-removed: Obsoleted comment about shared FileDescriptor handling.
close();
}
}
}