/*
* 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 static android.system.OsConstants.AF_UNIX;
import static android.system.OsConstants.SEEK_SET;
import static android.system.OsConstants.SOCK_STREAM;
import static android.system.OsConstants.S_ISLNK;
import static android.system.OsConstants.S_ISREG;
import android.content.BroadcastReceiver;
import android.content.ContentProvider;
import android.system.ErrnoException;
import android.system.Os;
import android.system.OsConstants;
import android.system.StructStat;
import android.util.Log;
import dalvik.system.CloseGuard;
import libcore.io.IoUtils;
import libcore.io.Memory;
import java.io.Closeable;
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.io.InterruptedIOException;
import java.net.DatagramSocket;
import java.net.Socket;
import java.nio.ByteOrder;
/**
* The FileDescriptor returned by {@link Parcel#readFileDescriptor}, allowing
* you to close it when done with it.
*/
public class ParcelFileDescriptor implements Parcelable, Closeable {
private static final String TAG = "ParcelFileDescriptor";
private final FileDescriptor mFd;
/**
* Optional socket used to communicate close events, status at close, and
* detect remote process crashes.
*/
private FileDescriptor mCommFd;
/**
* Wrapped {@link ParcelFileDescriptor}, if any. Used to avoid
* double-closing {@link #mFd}.
*/
private final ParcelFileDescriptor mWrapped;
/**
* Maximum {@link #mStatusBuf} size; longer status messages will be
* truncated.
*/
private static final int MAX_STATUS = 1024;
/**
* Temporary buffer used by {@link #readCommStatus(FileDescriptor, byte[])},
* allocated on-demand.
*/
private byte[] mStatusBuf;
/**
* Status read by {@link #checkError()}, or null if not read yet.
*/
private Status mStatus;
private volatile boolean mClosed;
private final CloseGuard mGuard = CloseGuard.get();
/**
* 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.
*
* @deprecated Creating world-readable files is very dangerous, and likely
* to cause security holes in applications. It is strongly
* discouraged; instead, applications should use more formal
* mechanism for interactions such as {@link ContentProvider},
* {@link BroadcastReceiver}, and {@link android.app.Service}.
* There are no guarantees that this access mode will remain on
* a file, such as when it goes through a backup and restore.
*/
@Deprecated
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.
*
* @deprecated Creating world-writable files is very dangerous, and likely
* to cause security holes in applications. It is strongly
* discouraged; instead, applications should use more formal
* mechanism for interactions such as {@link ContentProvider},
* {@link BroadcastReceiver}, and {@link android.app.Service}.
* There are no guarantees that this access mode will remain on
* a file, such as when it goes through a backup and restore.
*/
@Deprecated
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 wrapped around another descriptor. By
* default all method calls are delegated to the wrapped descriptor.
*/
public ParcelFileDescriptor(ParcelFileDescriptor wrapped) {
// We keep a strong reference to the wrapped PFD, and rely on its
// finalizer to trigger CloseGuard. All calls are delegated to wrapper.
mWrapped = wrapped;
mFd = null;
mCommFd = null;
mClosed = true;
}
/** {@hide} */
public ParcelFileDescriptor(FileDescriptor fd) {
this(fd, null);
}
/** {@hide} */
public ParcelFileDescriptor(FileDescriptor fd, FileDescriptor commChannel) {
if (fd == null) {
throw new NullPointerException("FileDescriptor must not be null");
}
mWrapped = null;
mFd = fd;
mCommFd = commChannel;
mGuard.open("close");
}
/**
* 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 a new ParcelFileDescriptor pointing to the given file.
* @throws FileNotFoundException if the given file does not exist or can not
* be opened with the requested mode.
* @see #parseMode(String)
*/
public static ParcelFileDescriptor open(File file, int mode) throws FileNotFoundException {
final FileDescriptor fd = openInternal(file, mode);
if (fd == null) return null;
return new ParcelFileDescriptor(fd);
}
/**
* 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}.
* @param handler to call listener from; must not be null.
* @param listener to be invoked when the returned descriptor has been
* closed; must not be null.
* @return a new ParcelFileDescriptor pointing to the given file.
* @throws FileNotFoundException if the given file does not exist or can not
* be opened with the requested mode.
* @see #parseMode(String)
*/
public static ParcelFileDescriptor open(
File file, int mode, Handler handler, OnCloseListener listener) throws IOException {
if (handler == null) {
throw new IllegalArgumentException("Handler must not be null");
}
if (listener == null) {
throw new IllegalArgumentException("Listener must not be null");
}
final FileDescriptor fd = openInternal(file, mode);
if (fd == null) return null;
final FileDescriptor[] comm = createCommSocketPair();
final ParcelFileDescriptor pfd = new ParcelFileDescriptor(fd, comm[0]);
// Kick off thread to watch for status updates
IoUtils.setBlocking(comm[1], true);
final ListenerBridge bridge = new ListenerBridge(comm[1], handler.getLooper(), listener);
bridge.start();
return pfd;
}
private static FileDescriptor openInternal(File file, int mode) throws FileNotFoundException {
if ((mode & MODE_READ_WRITE) == 0) {
throw new IllegalArgumentException(
"Must specify MODE_READ_ONLY, MODE_WRITE_ONLY, or MODE_READ_WRITE");
}
final String path = file.getPath();
return Parcel.openFileDescriptor(path, mode);
}
/**
* 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 {
try {
final FileDescriptor fd = Os.dup(orig);
return new ParcelFileDescriptor(fd);
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
/**
* 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 {
if (mWrapped != null) {
return mWrapped.dup();
} else {
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 {
final FileDescriptor original = new FileDescriptor();
original.setInt$(fd);
try {
final FileDescriptor dup = Os.dup(original);
return new ParcelFileDescriptor(dup);
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
/**
* Take ownership of a raw native fd in to a new ParcelFileDescriptor.
* The returned ParcelFileDescriptor now owns the given fd, and will be
* responsible for closing it. You must not close the fd yourself.
*
* @param fd The native fd that the ParcelFileDescriptor should adopt.
*
* @return Returns a new ParcelFileDescriptor holding a FileDescriptor
* for the given fd.
*/
public static ParcelFileDescriptor adoptFd(int fd) {
final FileDescriptor fdesc = new FileDescriptor();
fdesc.setInt$(fd);
return new ParcelFileDescriptor(fdesc);
}
/**
* 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 {
try {
final FileDescriptor[] fds = Os.pipe();
return new ParcelFileDescriptor[] {
new ParcelFileDescriptor(fds[0]),
new ParcelFileDescriptor(fds[1]) };
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
/**
* 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.
* <p>
* The write end has the ability to deliver an error message through
* {@link #closeWithError(String)} which can be handled by the read end
* calling {@link #checkError()}, usually after detecting an EOF.
* This can also be used to detect remote crashes.
*/
public static ParcelFileDescriptor[] createReliablePipe() throws IOException {
try {
final FileDescriptor[] comm = createCommSocketPair();
final FileDescriptor[] fds = Os.pipe();
return new ParcelFileDescriptor[] {
new ParcelFileDescriptor(fds[0], comm[0]),
new ParcelFileDescriptor(fds[1], comm[1]) };
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
/**
* Create two ParcelFileDescriptors structured as a pair of sockets
* connected to each other. The two sockets are indistinguishable.
*/
public static ParcelFileDescriptor[] createSocketPair() throws IOException {
try {
final FileDescriptor fd0 = new FileDescriptor();
final FileDescriptor fd1 = new FileDescriptor();
Os.socketpair(AF_UNIX, SOCK_STREAM, 0, fd0, fd1);
return new ParcelFileDescriptor[] {
new ParcelFileDescriptor(fd0),
new ParcelFileDescriptor(fd1) };
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
/**
* Create two ParcelFileDescriptors structured as a pair of sockets
* connected to each other. The two sockets are indistinguishable.
* <p>
* Both ends have the ability to deliver an error message through
* {@link #closeWithError(String)} which can be detected by the other end
* calling {@link #checkError()}, usually after detecting an EOF.
* This can also be used to detect remote crashes.
*/
public static ParcelFileDescriptor[] createReliableSocketPair() throws IOException {
try {
final FileDescriptor[] comm = createCommSocketPair();
final FileDescriptor fd0 = new FileDescriptor();
final FileDescriptor fd1 = new FileDescriptor();
Os.socketpair(AF_UNIX, SOCK_STREAM, 0, fd0, fd1);
return new ParcelFileDescriptor[] {
new ParcelFileDescriptor(fd0, comm[0]),
new ParcelFileDescriptor(fd1, comm[1]) };
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
private static FileDescriptor[] createCommSocketPair() throws IOException {
try {
final FileDescriptor comm1 = new FileDescriptor();
final FileDescriptor comm2 = new FileDescriptor();
Os.socketpair(AF_UNIX, SOCK_STREAM, 0, comm1, comm2);
IoUtils.setBlocking(comm1, false);
IoUtils.setBlocking(comm2, false);
return new FileDescriptor[] { comm1, comm2 };
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
/**
* @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;
}
/**
* Converts a string representing a file mode, such as "rw", into a bitmask suitable for use
* with {@link #open}.
* <p>
* @param mode The string representation of the file mode.
* @return A bitmask representing the given file mode.
* @throws IllegalArgumentException if the given string does not match a known file mode.
*/
public static int parseMode(String mode) {
final int modeBits;
if ("r".equals(mode)) {
modeBits = ParcelFileDescriptor.MODE_READ_ONLY;
} else if ("w".equals(mode) || "wt".equals(mode)) {
modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY
| ParcelFileDescriptor.MODE_CREATE
| ParcelFileDescriptor.MODE_TRUNCATE;
} else if ("wa".equals(mode)) {
modeBits = ParcelFileDescriptor.MODE_WRITE_ONLY
| ParcelFileDescriptor.MODE_CREATE
| ParcelFileDescriptor.MODE_APPEND;
} else if ("rw".equals(mode)) {
modeBits = ParcelFileDescriptor.MODE_READ_WRITE
| ParcelFileDescriptor.MODE_CREATE;
} else if ("rwt".equals(mode)) {
modeBits = ParcelFileDescriptor.MODE_READ_WRITE
| ParcelFileDescriptor.MODE_CREATE
| ParcelFileDescriptor.MODE_TRUNCATE;
} else {
throw new IllegalArgumentException("Bad mode '" + mode + "'");
}
return modeBits;
}
/**
* Retrieve the actual FileDescriptor associated with this object.
*
* @return Returns the FileDescriptor associated with this object.
*/
public FileDescriptor getFileDescriptor() {
if (mWrapped != null) {
return mWrapped.getFileDescriptor();
} else {
return mFd;
}
}
/**
* Return the total size of the file representing this fd, as determined by
* {@code stat()}. Returns -1 if the fd is not a file.
*/
public long getStatSize() {
if (mWrapped != null) {
return mWrapped.getStatSize();
} else {
try {
final StructStat st = Os.fstat(mFd);
if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
return st.st_size;
} else {
return -1;
}
} catch (ErrnoException e) {
Log.w(TAG, "fstat() failed: " + e);
return -1;
}
}
}
/**
* This is needed for implementing AssetFileDescriptor.AutoCloseOutputStream,
* and I really don't think we want it to be public.
* @hide
*/
public long seekTo(long pos) throws IOException {
if (mWrapped != null) {
return mWrapped.seekTo(pos);
} else {
try {
return Os.lseek(mFd, pos, SEEK_SET);
} catch (ErrnoException e) {
throw e.rethrowAsIOException();
}
}
}
/**
* 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 (mWrapped != null) {
return mWrapped.getFd();
} else {
if (mClosed) {
throw new IllegalStateException("Already closed");
}
return mFd.getInt$();
}
}
/**
* 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.
* <p>
* You should not detach when the original creator of the descriptor is
* expecting a reliable signal through {@link #close()} or
* {@link #closeWithError(String)}.
*
* @see #canDetectErrors()
*/
public int detachFd() {
if (mWrapped != null) {
return mWrapped.detachFd();
} else {
if (mClosed) {
throw new IllegalStateException("Already closed");
}
final int fd = getFd();
Parcel.clearFileDescriptor(mFd);
writeCommStatusAndClose(Status.DETACHED, null);
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.
*/
@Override
public void close() throws IOException {
if (mWrapped != null) {
try {
mWrapped.close();
} finally {
releaseResources();
}
} else {
closeWithStatus(Status.OK, null);
}
}
/**
* Close the ParcelFileDescriptor, informing any peer that an error occurred
* while processing. If the creator of this descriptor is not observing
* errors, it will close normally.
*
* @param msg describing the error; must not be null.
*/
public void closeWithError(String msg) throws IOException {
if (mWrapped != null) {
try {
mWrapped.closeWithError(msg);
} finally {
releaseResources();
}
} else {
if (msg == null) {
throw new IllegalArgumentException("Message must not be null");
}
closeWithStatus(Status.ERROR, msg);
}
}
private void closeWithStatus(int status, String msg) {
if (mClosed) return;
mClosed = true;
mGuard.close();
// Status MUST be sent before closing actual descriptor
writeCommStatusAndClose(status, msg);
IoUtils.closeQuietly(mFd);
releaseResources();
}
/**
* Called when the fd is being closed, for subclasses to release any other resources
* associated with it, such as acquired providers.
* @hide
*/
public void releaseResources() {
}
private byte[] getOrCreateStatusBuffer() {
if (mStatusBuf == null) {
mStatusBuf = new byte[MAX_STATUS];
}
return mStatusBuf;
}
private void writeCommStatusAndClose(int status, String msg) {
if (mCommFd == null) {
// Not reliable, or someone already sent status
if (msg != null) {
Log.w(TAG, "Unable to inform peer: " + msg);
}
return;
}
if (status == Status.DETACHED) {
Log.w(TAG, "Peer expected signal when closed; unable to deliver after detach");
}
try {
if (status == Status.SILENCE) return;
// Since we're about to close, read off any remote status. It's
// okay to remember missing here.
mStatus = readCommStatus(mCommFd, getOrCreateStatusBuffer());
// Skip writing status when other end has already gone away.
if (mStatus != null) return;
try {
final byte[] buf = getOrCreateStatusBuffer();
int writePtr = 0;
Memory.pokeInt(buf, writePtr, status, ByteOrder.BIG_ENDIAN);
writePtr += 4;
if (msg != null) {
final byte[] rawMsg = msg.getBytes();
final int len = Math.min(rawMsg.length, buf.length - writePtr);
System.arraycopy(rawMsg, 0, buf, writePtr, len);
writePtr += len;
}
Os.write(mCommFd, buf, 0, writePtr);
} catch (ErrnoException e) {
// Reporting status is best-effort
Log.w(TAG, "Failed to report status: " + e);
} catch (InterruptedIOException e) {
// Reporting status is best-effort
Log.w(TAG, "Failed to report status: " + e);
}
} finally {
IoUtils.closeQuietly(mCommFd);
mCommFd = null;
}
}
private static Status readCommStatus(FileDescriptor comm, byte[] buf) {
try {
final int n = Os.read(comm, buf, 0, buf.length);
if (n == 0) {
// EOF means they're dead
return new Status(Status.DEAD);
} else {
final int status = Memory.peekInt(buf, 0, ByteOrder.BIG_ENDIAN);
if (status == Status.ERROR) {
final String msg = new String(buf, 4, n - 4);
return new Status(status, msg);
}
return new Status(status);
}
} catch (ErrnoException e) {
if (e.errno == OsConstants.EAGAIN) {
// Remote is still alive, but no status written yet
return null;
} else {
Log.d(TAG, "Failed to read status; assuming dead: " + e);
return new Status(Status.DEAD);
}
} catch (InterruptedIOException e) {
Log.d(TAG, "Failed to read status; assuming dead: " + e);
return new Status(Status.DEAD);
}
}
/**
* Indicates if this ParcelFileDescriptor can communicate and detect remote
* errors/crashes.
*
* @see #checkError()
*/
public boolean canDetectErrors() {
if (mWrapped != null) {
return mWrapped.canDetectErrors();
} else {
return mCommFd != null;
}
}
/**
* Detect and throw if the other end of a pipe or socket pair encountered an
* error or crashed. This allows a reader to distinguish between a valid EOF
* and an error/crash.
* <p>
* If this ParcelFileDescriptor is unable to detect remote errors, it will
* return silently.
*
* @throws IOException for normal errors.
* @throws FileDescriptorDetachedException
* if the remote side called {@link #detachFd()}. Once detached, the remote
* side is unable to communicate any errors through
* {@link #closeWithError(String)}.
* @see #canDetectErrors()
*/
public void checkError() throws IOException {
if (mWrapped != null) {
mWrapped.checkError();
} else {
if (mStatus == null) {
if (mCommFd == null) {
Log.w(TAG, "Peer didn't provide a comm channel; unable to check for errors");
return;
}
// Try reading status; it might be null if nothing written yet.
// Either way, we keep comm open to write our status later.
mStatus = readCommStatus(mCommFd, getOrCreateStatusBuffer());
}
if (mStatus == null || mStatus.status == Status.OK) {
// No status yet, or everything is peachy!
return;
} else {
throw mStatus.asIOException();
}
}
}
/**
* 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 mPfd;
public AutoCloseInputStream(ParcelFileDescriptor pfd) {
super(pfd.getFileDescriptor());
mPfd = pfd;
}
@Override
public void close() throws IOException {
try {
mPfd.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 mPfd;
public AutoCloseOutputStream(ParcelFileDescriptor pfd) {
super(pfd.getFileDescriptor());
mPfd = pfd;
}
@Override
public void close() throws IOException {
try {
mPfd.close();
} finally {
super.close();
}
}
}
@Override
public String toString() {
if (mWrapped != null) {
return mWrapped.toString();
} else {
return "{ParcelFileDescriptor: " + mFd + "}";
}
}
@Override
protected void finalize() throws Throwable {
if (mWrapped != null) {
releaseResources();
}
if (mGuard != null) {
mGuard.warnIfOpen();
}
try {
if (!mClosed) {
closeWithStatus(Status.LEAKED, null);
}
} finally {
super.finalize();
}
}
@Override
public int describeContents() {
if (mWrapped != null) {
return mWrapped.describeContents();
} else {
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.
*/
@Override
public void writeToParcel(Parcel out, int flags) {
// WARNING: This must stay in sync with Parcel::readParcelFileDescriptor()
// in frameworks/native/libs/binder/Parcel.cpp
if (mWrapped != null) {
try {
mWrapped.writeToParcel(out, flags);
} finally {
releaseResources();
}
} else {
out.writeFileDescriptor(mFd);
if (mCommFd != null) {
out.writeInt(1);
out.writeFileDescriptor(mCommFd);
} else {
out.writeInt(0);
}
if ((flags & PARCELABLE_WRITE_RETURN_VALUE) != 0 && !mClosed) {
// Not a real close, so emit no status
closeWithStatus(Status.SILENCE, null);
}
}
}
public static final Parcelable.Creator<ParcelFileDescriptor> CREATOR
= new Parcelable.Creator<ParcelFileDescriptor>() {
@Override
public ParcelFileDescriptor createFromParcel(Parcel in) {
// WARNING: This must stay in sync with Parcel::writeParcelFileDescriptor()
// in frameworks/native/libs/binder/Parcel.cpp
final FileDescriptor fd = in.readRawFileDescriptor();
FileDescriptor commChannel = null;
if (in.readInt() != 0) {
commChannel = in.readRawFileDescriptor();
}
return new ParcelFileDescriptor(fd, commChannel);
}
@Override
public ParcelFileDescriptor[] newArray(int size) {
return new ParcelFileDescriptor[size];
}
};
/**
* Callback indicating that a ParcelFileDescriptor has been closed.
*/
public interface OnCloseListener {
/**
* Event indicating the ParcelFileDescriptor to which this listener was
* attached has been closed.
*
* @param e error state, or {@code null} if closed cleanly.
* If the close event was the result of
* {@link ParcelFileDescriptor#detachFd()}, this will be a
* {@link FileDescriptorDetachedException}. After detach the
* remote side may continue reading/writing to the underlying
* {@link FileDescriptor}, but they can no longer deliver
* reliable close/error events.
*/
public void onClose(IOException e);
}
/**
* Exception that indicates that the file descriptor was detached.
*/
public static class FileDescriptorDetachedException extends IOException {
private static final long serialVersionUID = 0xDe7ac4edFdL;
public FileDescriptorDetachedException() {
super("Remote side is detached");
}
}
/**
* Internal class representing a remote status read by
* {@link ParcelFileDescriptor#readCommStatus(FileDescriptor, byte[])}.
*/
private static class Status {
/** Special value indicating remote side died. */
public static final int DEAD = -2;
/** Special value indicating no status should be written. */
public static final int SILENCE = -1;
/** Remote reported that everything went better than expected. */
public static final int OK = 0;
/** Remote reported error; length and message follow. */
public static final int ERROR = 1;
/** Remote reported {@link #detachFd()} and went rogue. */
public static final int DETACHED = 2;
/** Remote reported their object was finalized. */
public static final int LEAKED = 3;
public final int status;
public final String msg;
public Status(int status) {
this(status, null);
}
public Status(int status, String msg) {
this.status = status;
this.msg = msg;
}
public IOException asIOException() {
switch (status) {
case DEAD:
return new IOException("Remote side is dead");
case OK:
return null;
case ERROR:
return new IOException("Remote error: " + msg);
case DETACHED:
return new FileDescriptorDetachedException();
case LEAKED:
return new IOException("Remote side was leaked");
default:
return new IOException("Unknown status: " + status);
}
}
}
/**
* Bridge to watch for remote status, and deliver to listener. Currently
* requires that communication socket is <em>blocking</em>.
*/
private static final class ListenerBridge extends Thread {
// TODO: switch to using Looper to avoid burning a thread
private FileDescriptor mCommFd;
private final Handler mHandler;
public ListenerBridge(FileDescriptor comm, Looper looper, final OnCloseListener listener) {
mCommFd = comm;
mHandler = new Handler(looper) {
@Override
public void handleMessage(Message msg) {
final Status s = (Status) msg.obj;
listener.onClose(s != null ? s.asIOException() : null);
}
};
}
@Override
public void run() {
try {
final byte[] buf = new byte[MAX_STATUS];
final Status status = readCommStatus(mCommFd, buf);
mHandler.obtainMessage(0, status).sendToTarget();
} finally {
IoUtils.closeQuietly(mCommFd);
mCommFd = null;
}
}
}
}
