/*
* Copyright (C) 2006 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.os;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.DatagramSocket;
import java.net.Socket;
/**
* The FileDescriptor returned by {@link Parcel#readFileDescriptor}, allowing
* you to close it when done with it.
*/
public class ParcelFileDescriptor implements Parcelable {
private final FileDescriptor mFileDescriptor;
private boolean mClosed;
//this field is to create wrapper for ParcelFileDescriptor using another
//PartialFileDescriptor but avoid invoking close twice
//consider ParcelFileDescriptor A(fileDescriptor fd), ParcelFileDescriptor B(A)
//in this particular case fd.close might be invoked twice.
private final ParcelFileDescriptor mParcelDescriptor;
/**
* For use with {@link #open}: if {@link #MODE_CREATE} has been supplied
* and this file doesn't already exist, then create the file with
* permissions such that any application can read it.
*/
public static final int MODE_WORLD_READABLE = 0x00000001;
/**
* For use with {@link #open}: if {@link #MODE_CREATE} has been supplied
* and this file doesn't already exist, then create the file with
* permissions such that any application can write it.
*/
public static final int MODE_WORLD_WRITEABLE = 0x00000002;
/**
* For use with {@link #open}: open the file with read-only access.
*/
public static final int MODE_READ_ONLY = 0x10000000;
/**
* For use with {@link #open}: open the file with write-only access.
*/
public static final int MODE_WRITE_ONLY = 0x20000000;
/**
* For use with {@link #open}: open the file with read and write access.
*/
public static final int MODE_READ_WRITE = 0x30000000;
/**
* For use with {@link #open}: create the file if it doesn't already exist.
*/
public static final int MODE_CREATE = 0x08000000;
/**
* For use with {@link #open}: erase contents of file when opening.
*/
public static final int MODE_TRUNCATE = 0x04000000;
/**
* For use with {@link #open}: append to end of file while writing.
*/
public static final int MODE_APPEND = 0x02000000;
/**
* Create a new ParcelFileDescriptor accessing a given file.
*
* @param file The file to be opened.
* @param mode The desired access mode, must be one of
* {@link #MODE_READ_ONLY}, {@link #MODE_WRITE_ONLY}, or
* {@link #MODE_READ_WRITE}; may also be any combination of
* {@link #MODE_CREATE}, {@link #MODE_TRUNCATE},
* {@link #MODE_WORLD_READABLE}, and {@link #MODE_WORLD_WRITEABLE}.
*
* @return Returns a new ParcelFileDescriptor pointing to the given
* file.
*
* @throws FileNotFoundException Throws FileNotFoundException if the given
* file does not exist or can not be opened with the requested mode.
*/
public static ParcelFileDescriptor open(File file, int mode)
throws FileNotFoundException {
String path = file.getPath();
SecurityManager security = System.getSecurityManager();
if (security != null) {
security.checkRead(path);
if ((mode&MODE_WRITE_ONLY) != 0) {
security.checkWrite(path);
}
}
if ((mode&MODE_READ_WRITE) == 0) {
throw new IllegalArgumentException(
"Must specify MODE_READ_ONLY, MODE_WRITE_ONLY, or MODE_READ_WRITE");
}
FileDescriptor fd = Parcel.openFileDescriptor(path, mode);
return fd != null ? new ParcelFileDescriptor(fd) : null;
}
/**
* Create a new ParcelFileDescriptor that is a dup of an existing
* FileDescriptor. This obeys standard POSIX semantics, where the
* new file descriptor shared state such as file position with the
* original file descriptor.
*/
public static ParcelFileDescriptor dup(FileDescriptor orig) throws IOException {
FileDescriptor fd = Parcel.dupFileDescriptor(orig);
return fd != null ? new ParcelFileDescriptor(fd) : null;
}
/**
* Create a new ParcelFileDescriptor that is a dup of the existing
* FileDescriptor. This obeys standard POSIX semantics, where the
* new file descriptor shared state such as file position with the
* original file descriptor.
*/
public ParcelFileDescriptor dup() throws IOException {
return dup(getFileDescriptor());
}
/**
* Create a new ParcelFileDescriptor from a raw native fd. The new
* ParcelFileDescriptor holds a dup of the original fd passed in here,
* so you must still close that fd as well as the new ParcelFileDescriptor.
*
* @param fd The native fd that the ParcelFileDescriptor should dup.
*
* @return Returns a new ParcelFileDescriptor holding a FileDescriptor
* for a dup of the given fd.
*/
public static ParcelFileDescriptor fromFd(int fd) throws IOException {
FileDescriptor fdesc = getFileDescriptorFromFd(fd);
return new ParcelFileDescriptor(fdesc);
}
// Extracts the file descriptor from the specified socket and returns it untouched
private static native FileDescriptor getFileDescriptorFromFd(int fd) throws IOException;
/**
* Take ownership of a raw native fd in to a new ParcelFileDescriptor.
* The returned ParcelFileDescriptor now owns the given fd, and will be
* responsible for closing it. You must not close the fd yourself.
*
* @param fd The native fd that the ParcelFileDescriptor should adopt.
*
* @return Returns a new ParcelFileDescriptor holding a FileDescriptor
* for the given fd.
*/
public static ParcelFileDescriptor adoptFd(int fd) {
FileDescriptor fdesc = getFileDescriptorFromFdNoDup(fd);
return new ParcelFileDescriptor(fdesc);
}
// Extracts the file descriptor from the specified socket and returns it untouched
private static native FileDescriptor getFileDescriptorFromFdNoDup(int fd);
/**
* Create a new ParcelFileDescriptor from the specified Socket. The new
* ParcelFileDescriptor holds a dup of the original FileDescriptor in
* the Socket, so you must still close the Socket as well as the new
* ParcelFileDescriptor.
*
* @param socket The Socket whose FileDescriptor is used to create
* a new ParcelFileDescriptor.
*
* @return A new ParcelFileDescriptor with the FileDescriptor of the
* specified Socket.
*/
public static ParcelFileDescriptor fromSocket(Socket socket) {
FileDescriptor fd = socket.getFileDescriptor$();
return fd != null ? new ParcelFileDescriptor(fd) : null;
}
/**
* Create a new ParcelFileDescriptor from the specified DatagramSocket.
*
* @param datagramSocket The DatagramSocket whose FileDescriptor is used
* to create a new ParcelFileDescriptor.
*
* @return A new ParcelFileDescriptor with the FileDescriptor of the
* specified DatagramSocket.
*/
public static ParcelFileDescriptor fromDatagramSocket(DatagramSocket datagramSocket) {
FileDescriptor fd = datagramSocket.getFileDescriptor$();
return fd != null ? new ParcelFileDescriptor(fd) : null;
}
/**
* Create two ParcelFileDescriptors structured as a data pipe. The first
* ParcelFileDescriptor in the returned array is the read side; the second
* is the write side.
*/
public static ParcelFileDescriptor[] createPipe() throws IOException {
FileDescriptor[] fds = new FileDescriptor[2];
createPipeNative(fds);
ParcelFileDescriptor[] pfds = new ParcelFileDescriptor[2];
pfds[0] = new ParcelFileDescriptor(fds[0]);
pfds[1] = new ParcelFileDescriptor(fds[1]);
return pfds;
}
private static native void createPipeNative(FileDescriptor[] outFds) throws IOException;
/**
* @hide Please use createPipe() or ContentProvider.openPipeHelper().
* Gets a file descriptor for a read-only copy of the given data.
*
* @param data Data to copy.
* @param name Name for the shared memory area that may back the file descriptor.
* This is purely informative and may be {@code null}.
* @return A ParcelFileDescriptor.
* @throws IOException if there is an error while creating the shared memory area.
*/
@Deprecated
public static ParcelFileDescriptor fromData(byte[] data, String name) throws IOException {
if (data == null) return null;
MemoryFile file = new MemoryFile(name, data.length);
if (data.length > 0) {
file.writeBytes(data, 0, 0, data.length);
}
file.deactivate();
FileDescriptor fd = file.getFileDescriptor();
return fd != null ? new ParcelFileDescriptor(fd) : null;
}
/**
* Retrieve the actual FileDescriptor associated with this object.
*
* @return Returns the FileDescriptor associated with this object.
*/
public FileDescriptor getFileDescriptor() {
return mFileDescriptor;
}
/**
* Return the total size of the file representing this fd, as determined
* by stat(). Returns -1 if the fd is not a file.
*/
public native long getStatSize();
/**
* This is needed for implementing AssetFileDescriptor.AutoCloseOutputStream,
* and I really don't think we want it to be public.
* @hide
*/
public native long seekTo(long pos);
/**
* Return the native fd int for this ParcelFileDescriptor. The
* ParcelFileDescriptor still owns the fd, and it still must be closed
* through this API.
*/
public int getFd() {
if (mClosed) {
throw new IllegalStateException("Already closed");
}
return getFdNative();
}
private native int getFdNative();
/**
* Return the native fd int for this ParcelFileDescriptor and detach it
* from the object here. You are now responsible for closing the fd in
* native code.
*/
public int detachFd() {
if (mClosed) {
throw new IllegalStateException("Already closed");
}
if (mParcelDescriptor != null) {
int fd = mParcelDescriptor.detachFd();
mClosed = true;
return fd;
}
int fd = getFd();
mClosed = true;
Parcel.clearFileDescriptor(mFileDescriptor);
return fd;
}
/**
* Close the ParcelFileDescriptor. This implementation closes the underlying
* OS resources allocated to represent this stream.
*
* @throws IOException
* If an error occurs attempting to close this ParcelFileDescriptor.
*/
public void close() throws IOException {
synchronized (this) {
if (mClosed) return;
mClosed = true;
}
if (mParcelDescriptor != null) {
// If this is a proxy to another file descriptor, just call through to its
// close method.
mParcelDescriptor.close();
} else {
Parcel.closeFileDescriptor(mFileDescriptor);
}
}
/**
* An InputStream you can create on a ParcelFileDescriptor, which will
* take care of calling {@link ParcelFileDescriptor#close
* ParcelFileDescriptor.close()} for you when the stream is closed.
*/
public static class AutoCloseInputStream extends FileInputStream {
private final ParcelFileDescriptor mFd;
public AutoCloseInputStream(ParcelFileDescriptor fd) {
super(fd.getFileDescriptor());
mFd = fd;
}
@Override
public void close() throws IOException {
try {
mFd.close();
} finally {
super.close();
}
}
}
/**
* An OutputStream you can create on a ParcelFileDescriptor, which will
* take care of calling {@link ParcelFileDescriptor#close
* ParcelFileDescriptor.close()} for you when the stream is closed.
*/
public static class AutoCloseOutputStream extends FileOutputStream {
private final ParcelFileDescriptor mFd;
public AutoCloseOutputStream(ParcelFileDescriptor fd) {
super(fd.getFileDescriptor());
mFd = fd;
}
@Override
public void close() throws IOException {
try {
mFd.close();
} finally {
super.close();
}
}
}
@Override
public String toString() {
return "{ParcelFileDescriptor: " + mFileDescriptor + "}";
}
@Override
protected void finalize() throws Throwable {
try {
if (!mClosed) {
close();
}
} finally {
super.finalize();
}
}
public ParcelFileDescriptor(ParcelFileDescriptor descriptor) {
super();
mParcelDescriptor = descriptor;
mFileDescriptor = mParcelDescriptor.mFileDescriptor;
}
/*package */ParcelFileDescriptor(FileDescriptor descriptor) {
super();
if (descriptor == null) {
throw new NullPointerException("descriptor must not be null");
}
mFileDescriptor = descriptor;
mParcelDescriptor = null;
}
/* Parcelable interface */
public int describeContents() {
return Parcelable.CONTENTS_FILE_DESCRIPTOR;
}
/**
* {@inheritDoc}
* If {@link Parcelable#PARCELABLE_WRITE_RETURN_VALUE} is set in flags,
* the file descriptor will be closed after a copy is written to the Parcel.
*/
public void writeToParcel(Parcel out, int flags) {
out.writeFileDescriptor(mFileDescriptor);
if ((flags&PARCELABLE_WRITE_RETURN_VALUE) != 0 && !mClosed) {
try {
close();
} catch (IOException e) {
// Empty
}
}
}
public static final Parcelable.Creator<ParcelFileDescriptor> CREATOR
= new Parcelable.Creator<ParcelFileDescriptor>() {
public ParcelFileDescriptor createFromParcel(Parcel in) {
return in.readFileDescriptor();
}
public ParcelFileDescriptor[] newArray(int size) {
return new ParcelFileDescriptor[size];
}
};
}