HBASE-6316 Confirm can upgrade to 0.96 from 0.94 by just stopping and restarting

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1396428 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/io/Reference.java

@@ -20,12 +20,12 @@ package org.apache.hadoop.hbase.io;
 
 import java.io.BufferedInputStream;
 import java.io.DataInput;
+import java.io.DataInputStream;
 import java.io.DataOutput;
 import java.io.IOException;
 import java.io.InputStream;
 
 import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
@@ -175,9 +175,27 @@ public class Reference implements Writable {
    */
   public static Reference read(final FileSystem fs, final Path p)
   throws IOException {
-    FSDataInputStream in = fs.open(p);
+    InputStream in = fs.open(p);
     try {
-      return parseFrom(in);
+      // I need to be able to move back in the stream if this is not a pb serialization so I can
+      // do the Writable decoding instead.
+      in = in.markSupported()? in: new BufferedInputStream(in);
+      int pblen = ProtobufUtil.lengthOfPBMagic();
+      in.mark(pblen);
+      byte [] pbuf = new byte[pblen];
+      int read = in.read(pbuf);
+      if (read != pblen) throw new IOException("read=" + read + ", wanted=" + pblen);
+      // WATCHOUT! Return in middle of function!!!
+      if (ProtobufUtil.isPBMagicPrefix(pbuf)) return convert(FSProtos.Reference.parseFrom(in));
+      // Else presume Writables.  Need to reset the stream since it didn't start w/ pb.
+      // We won't bother rewriting thie Reference as a pb since Reference is transitory.
+      in.reset();
+      Reference r = new Reference();
+      DataInputStream dis = new DataInputStream(in);
+      // Set in = dis so it gets the close below in the finally on our way out.
+      in = dis;
+      r.readFields(dis);
+      return r;
     } finally {
       in.close();
     }
@@ -208,32 +226,4 @@ public class Reference implements Writable {
   byte [] toByteArray() throws IOException {
     return ProtobufUtil.prependPBMagic(convert().toByteArray());
   }
-
-  /**
-   * Parses an {@link Reference} instance from the passed in stream.  Presumes the
-   * Reference was serialized to the stream with {@link #toDelimitedByteArray()}
-   * @param in
-   * @return An instance of Reference.
-   * @throws IOException
-   */
-  static Reference parseFrom(final FSDataInputStream in) throws IOException {
-    // I need to be able to move back in the stream if this is not a pb serialization so I can
-    // do the Writable decoding instead.
-    InputStream is = in.markSupported()? in: new BufferedInputStream(in);
-    int pblen = ProtobufUtil.lengthOfPBMagic();
-    is.mark(pblen);
-    byte [] pbuf = new byte[pblen];
-    int read = is.read(pbuf);
-    if (read != pblen) throw new IOException("read=" + read + ", wanted=" + pblen);
-    if (ProtobufUtil.isPBMagicPrefix(pbuf)) {
-      return convert(FSProtos.Reference.parseFrom(is));
-    } else {
-      // Presume Writables.  Need to reset the stream since it didn't start w/ pb.
-      // We won't bother rewriting thie Reference as a pb since Reference is transitory.
-      in.reset();
-      Reference r = new Reference();
-      r.readFields(in);
-      return r;
-    }
-  }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/io/TestReference.java

@@ -0,0 +1,51 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.hbase.io;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.SmallTests;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+/**
+ * Reference tests that run on local fs.
+ */
+@Category(SmallTests.class)
+public class TestReference {
+  private final HBaseTestingUtility HTU = new HBaseTestingUtility();
+
+  /**
+   * See if we can parse a Reference that was written pre-0.96, i.e. a serialized Writable.
+   * Exercises the code path that parses Writables.
+   * @throws IOException
+   */
+  @Test
+  public void testParsingWritableReference() throws IOException {
+    // Read a Reference written w/ 0.94 out of the test data dir.
+    final String datafile = System.getProperty("project.build.testSourceDirectory", "src/test") +
+      File.separator + "data" + File.separator +
+      "a6a6562b777440fd9c34885428f5cb61.21e75333ada3d5bafb34bb918f29576c";
+    FileSystem fs = FileSystem.get(HTU.getConfiguration());
+    Reference.read(fs, new Path(datafile));
+  }
+}