6448457: (ch) Channels.newOutputStream().write() does not write all data

Reviewed-by: iris, sherman

jdk/src/share/classes/java/nio/channels/Channels.java

@@ -66,7 +66,27 @@ public final class Channels {
     private Channels() { }              // No instantiation
 
 
-    private static int write(WritableByteChannel ch, ByteBuffer bb)
+    /**
+     * Write all remaining bytes in buffer to the given channel.
+     * If the channel is selectable then it must be configured blocking.
+     */
+    private static void writeFullyImpl(WritableByteChannel ch, ByteBuffer bb)
+        throws IOException
+    {
+        while (bb.remaining() > 0) {
+            int n = ch.write(bb);
+            if (n <= 0)
+                throw new RuntimeException("no bytes written");
+        }
+    }
+
+    /**
+     * Write all remaining bytes in buffer to the given channel.
+     *
+     * @throws  IllegalBlockingException
+     *          If the channel is selectable and configured non-blocking.
+     */
+    private static void writeFully(WritableByteChannel ch, ByteBuffer bb)
         throws IOException
     {
         if (ch instanceof SelectableChannel) {
@@ -74,14 +94,13 @@ public final class Channels {
             synchronized (sc.blockingLock()) {
                 if (!sc.isBlocking())
                     throw new IllegalBlockingModeException();
-                return ch.write(bb);
+                writeFullyImpl(ch, bb);
             }
         } else {
-            return ch.write(bb);
+            writeFullyImpl(ch, bb);
         }
     }
 
-
     // -- Byte streams from channels --
 
     /**
@@ -148,7 +167,7 @@ public final class Channels {
                     bb.position(off);
                     this.bb = bb;
                     this.bs = bs;
-                    Channels.write(ch, bb);
+                    Channels.writeFully(ch, bb);
                 }
 
                 public void close() throws IOException {

jdk/test/java/nio/channels/Channels/ShortWrite.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  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.
+ *
+ * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/* @test
+ * @bug 6448457
+ * @summary Test Channels.newOutputStream returns OutputStream that handles
+ *     short writes from the underlying channel
+ */
+
+import java.io.OutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.*;
+import java.util.Random;
+
+public class ShortWrite {
+
+    static Random rand = new Random();
+    static int bytesWritten = 0;
+
+    public static void main(String[] args) throws IOException {
+
+        WritableByteChannel wbc = new WritableByteChannel() {
+            public int write(ByteBuffer src) {
+                int rem = src.remaining();
+                if (rem > 0) {
+                    // short write
+                    int n = rand.nextInt(rem) + 1;
+                    src.position(src.position() + n);
+                    bytesWritten += n;
+                    return n;
+                } else {
+                    return 0;
+                }
+            }
+            public void close() throws IOException {
+                throw new RuntimeException("not implemented");
+            }
+            public boolean isOpen() {
+                throw new RuntimeException("not implemented");
+            }
+        };
+
+        // wrap Channel with OutputStream
+        OutputStream out = Channels.newOutputStream(wbc);
+
+
+        // write 100, 99, 98, ... 1
+        // and check that the expected number of bytes is written
+        int expected = 0;
+        byte[] buf = new byte[100];
+        for (int i=0; i<buf.length; i++) {
+            int len = buf.length-i;
+            out.write(buf, i, len);
+            expected += len;
+        }
+        System.out.format("Bytes written: %d, expected: %d\n", bytesWritten,
+            expected);
+        if (bytesWritten != expected)
+            throw new RuntimeException("incorrect number of bytes written");
+
+    }
+}