Revert "Revert "Update ParcelFileDescriptor to use non-blocking I/O."" (6fd9f9af) · Commits · e / os / android_frameworks_base

core/java/android/os/ParcelFileDescriptor.java

+31 −39

Original line number	Original line	Diff line number	Diff line
	@@ -19,11 +19,13 @@ package android.os;
	import static android.system.OsConstants.AF_UNIX;		import static android.system.OsConstants.AF_UNIX;
	import static android.system.OsConstants.SEEK_SET;		import static android.system.OsConstants.SEEK_SET;
	import static android.system.OsConstants.SOCK_STREAM;		import static android.system.OsConstants.SOCK_STREAM;
			import static android.system.OsConstants.SOCK_SEQPACKET;
	import static android.system.OsConstants.S_ISLNK;		import static android.system.OsConstants.S_ISLNK;
	import static android.system.OsConstants.S_ISREG;		import static android.system.OsConstants.S_ISREG;

	import android.content.BroadcastReceiver;		import android.content.BroadcastReceiver;
	import android.content.ContentProvider;		import android.content.ContentProvider;
			import android.os.MessageQueue.FileDescriptorCallback;
	import android.system.ErrnoException;		import android.system.ErrnoException;
	import android.system.Os;		import android.system.Os;
	import android.system.OsConstants;		import android.system.OsConstants;
	@@ -31,7 +33,6 @@ import android.system.StructStat;
	import android.util.Log;		import android.util.Log;

	import dalvik.system.CloseGuard;		import dalvik.system.CloseGuard;

	import libcore.io.IoUtils;		import libcore.io.IoUtils;
	import libcore.io.Memory;		import libcore.io.Memory;

	@@ -220,8 +221,8 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
	* be opened with the requested mode.		* be opened with the requested mode.
	* @see #parseMode(String)		* @see #parseMode(String)
	*/		*/
	public static ParcelFileDescriptor open(		public static ParcelFileDescriptor open(File file, int mode, Handler handler,
	File file, int mode, Handler handler, OnCloseListener listener) throws IOException {		final OnCloseListener listener) throws IOException {
	if (handler == null) {		if (handler == null) {
	throw new IllegalArgumentException("Handler must not be null");		throw new IllegalArgumentException("Handler must not be null");
	}		}
	@@ -235,10 +236,25 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
	final FileDescriptor[] comm = createCommSocketPair();		final FileDescriptor[] comm = createCommSocketPair();
	final ParcelFileDescriptor pfd = new ParcelFileDescriptor(fd, comm[0]);		final ParcelFileDescriptor pfd = new ParcelFileDescriptor(fd, comm[0]);

	// Kick off thread to watch for status updates		handler.getLooper().getQueue().registerFileDescriptorCallback(comm[1],
	IoUtils.setBlocking(comm[1], true);		FileDescriptorCallback.EVENT_INPUT, new FileDescriptorCallback() {
	final ListenerBridge bridge = new ListenerBridge(comm[1], handler.getLooper(), listener);		@Override
	bridge.start();		public int onFileDescriptorEvents(FileDescriptor fd, int events) {
			Status status = null;
			if ((events & FileDescriptorCallback.EVENT_INPUT) != 0) {
			final byte[] buf = new byte[MAX_STATUS];
			status = readCommStatus(fd, buf);
			} else if ((events & FileDescriptorCallback.EVENT_ERROR) != 0) {
			status = new Status(Status.DEAD);
			}
			if (status != null) {
			IoUtils.closeQuietly(fd);
			listener.onClose(status.asIOException());
			return 0; // unregister the callback
			}
			return EVENT_INPUT;
			}
			});

	return pfd;		return pfd;
	}		}
	@@ -446,9 +462,12 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {

	private static FileDescriptor[] createCommSocketPair() throws IOException {		private static FileDescriptor[] createCommSocketPair() throws IOException {
	try {		try {
			// Use SOCK_SEQPACKET so that we have a guarantee that the status
			// is written and read atomically as one unit and is not split
			// across multiple IO operations.
	final FileDescriptor comm1 = new FileDescriptor();		final FileDescriptor comm1 = new FileDescriptor();
	final FileDescriptor comm2 = new FileDescriptor();		final FileDescriptor comm2 = new FileDescriptor();
	Os.socketpair(AF_UNIX, SOCK_STREAM, 0, comm1, comm2);		Os.socketpair(AF_UNIX, SOCK_SEQPACKET, 0, comm1, comm2);
	IoUtils.setBlocking(comm1, false);		IoUtils.setBlocking(comm1, false);
	IoUtils.setBlocking(comm2, false);		IoUtils.setBlocking(comm2, false);
	return new FileDescriptor[] { comm1, comm2 };		return new FileDescriptor[] { comm1, comm2 };
	@@ -709,6 +728,7 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
	writePtr += len;		writePtr += len;
	}		}

			// Must write the entire status as a single operation.
	Os.write(mCommFd, buf, 0, writePtr);		Os.write(mCommFd, buf, 0, writePtr);
	} catch (ErrnoException e) {		} catch (ErrnoException e) {
	// Reporting status is best-effort		// Reporting status is best-effort
	@@ -726,6 +746,7 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {

	private static Status readCommStatus(FileDescriptor comm, byte[] buf) {		private static Status readCommStatus(FileDescriptor comm, byte[] buf) {
	try {		try {
			// Must read the entire status as a single operation.
	final int n = Os.read(comm, buf, 0, buf.length);		final int n = Os.read(comm, buf, 0, buf.length);
	if (n == 0) {		if (n == 0) {
	// EOF means they're dead		// EOF means they're dead
	@@ -1014,39 +1035,10 @@ public class ParcelFileDescriptor implements Parcelable, Closeable {
	return new IOException("Unknown status: " + status);		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		@Override
	public void run() {		public String toString() {
	try {		return "{" + status + ": " + msg + "}";
	final byte[] buf = new byte[MAX_STATUS];
	final Status status = readCommStatus(mCommFd, buf);
	mHandler.obtainMessage(0, status).sendToTarget();
	} finally {
	IoUtils.closeQuietly(mCommFd);
	mCommFd = null;
	}
	}		}
	}		}
	}		}