8259956: jdk.jfr.internal.ChunkInputStream#available should return the sum of remaining available bytes

Reviewed-by: egahlin

src/jdk.jfr/share/classes/jdk/jfr/internal/ChunkInputStream.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2021, Oracle and/or its affiliates. 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
@@ -34,6 +34,7 @@ import java.util.List;
 
 final class ChunkInputStream extends InputStream {
     private final Iterator<RepositoryChunk> chunks;
+    private long unstreamedSize = 0;
     private RepositoryChunk currentChunk;
     private InputStream stream;
 
@@ -42,6 +43,7 @@ final class ChunkInputStream extends InputStream {
         for (RepositoryChunk c : chunks) {
             c.use(); // keep alive while we're reading.
             l.add(c);
+            unstreamedSize += c.getSize();
         }
 
         this.chunks = l.iterator();
@@ -50,10 +52,11 @@ final class ChunkInputStream extends InputStream {
 
     @Override
     public int available() throws IOException {
+        long total = unstreamedSize;
         if (stream != null) {
-            return stream.available();
+            total += stream.available();
         }
-        return 0;
+        return total <= Integer.MAX_VALUE ? (int) total : Integer.MAX_VALUE;
     }
 
     private boolean nextStream() throws IOException {
@@ -62,6 +65,7 @@ final class ChunkInputStream extends InputStream {
         }
 
         stream = new BufferedInputStream(SecuritySupport.newFileInputStream(currentChunk.getFile()));
+        unstreamedSize -= currentChunk.getSize();
         return true;
     }
 

test/jdk/jdk/jfr/api/consumer/TestChunkInputStreamAvailable.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2021, Alibaba Group Holding Limited. 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. Alibaba designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+
+/**
+ * @test TestChunkInputStreamAvailable
+ * @key jfr
+ * @requires vm.hasJFR
+ * @library /test/lib
+ * @run main/othervm jdk.jfr.api.consumer.TestChunkInputStreamAvailable
+ */
+package jdk.jfr.api.consumer;
+
+import java.io.InputStream;
+
+import jdk.jfr.Recording;
+import jdk.test.lib.Asserts;
+
+public class TestChunkInputStreamAvailable {
+
+    public static void main(String[] args) throws Exception {
+        try (Recording r = new Recording()) {
+            r.start();
+            try (Recording s = new Recording()) {
+                s.start();
+                s.stop();
+            }
+            r.stop();
+            try (InputStream stream = r.getStream(null, null)) {
+                int left = stream.available();
+                Asserts.assertEquals(r.getSize(), (long) left);
+                while (stream.read() != -1) {
+                    left--;
+                    Asserts.assertEquals(left, stream.available());
+                }
+                Asserts.assertEquals(0, left);
+            }
+        }
+    }
+}