# HG changeset patch
# User igerasim
# Date 1394682737 -14400
# Node ID b979b2e97874f2c8121ee9f5b011511364e6be50
# Parent  e73c2fb244de4cfde9fda948d597adf4708d1540
7011804: SequenceInputStream with lots of empty substreams can cause StackOverflowError
Reviewed-by: chegar, alanb

diff -r e73c2fb244de -r b979b2e97874 src/share/classes/java/io/SequenceInputStream.java
--- a/src/share/classes/java/io/SequenceInputStream.java	Fri May 09 09:47:07 2014 +0100
+++ b/src/share/classes/java/io/SequenceInputStream.java	Thu Mar 13 07:52:17 2014 +0400
@@ -135,7 +135,7 @@
      * @since   JDK1.1
      */
     public int available() throws IOException {
-        if(in == null) {
+        if (in == null) {
             return 0; // no way to signal EOF from available()
         }
         return in.available();
@@ -160,15 +160,14 @@
      * @exception  IOException  if an I/O error occurs.
      */
     public int read() throws IOException {
-        if (in == null) {
-            return -1;
+        while (in != null) {
+            int c = in.read();
+            if (c != -1) {
+                return c;
+            }
+            nextStream();
         }
-        int c = in.read();
-        if (c == -1) {
-            nextStream();
-            return read();
-        }
-        return c;
+        return -1;
     }
 
     /**
@@ -204,13 +203,14 @@
         } else if (len == 0) {
             return 0;
         }
-
-        int n = in.read(b, off, len);
-        if (n <= 0) {
+        do {
+            int n = in.read(b, off, len);
+            if (n > 0) {
+                return n;
+            }
             nextStream();
-            return read(b, off, len);
-        }
-        return n;
+        } while (in != null);
+        return -1;
     }
 
     /**
diff -r e73c2fb244de -r b979b2e97874 test/java/io/SequenceInputStream/LotsOfStreams.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/java/io/SequenceInputStream/LotsOfStreams.java	Thu Mar 13 07:52:17 2014 +0400
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2014, 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
+ * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 7011804
+ * @summary SequenceInputStream#read() was implemented recursivly,
+ *          which may cause stack overflow
+ */
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.io.SequenceInputStream;
+import java.util.Enumeration;
+
+public class LotsOfStreams {
+
+    static final int MAX_SUBSTREAMS = 32000;
+
+    public static void main(String[] argv) throws Exception {
+        try (InputStream stream =
+                new SequenceInputStream(new LOSEnumeration())) {
+            stream.read();
+        }
+        try (InputStream stream =
+                new SequenceInputStream(new LOSEnumeration())) {
+            byte[] b = new byte[1];
+            stream.read(b, 0, 1);
+        }
+    }
+
+    static class LOSEnumeration
+            implements Enumeration<InputStream> {
+
+        private static InputStream inputStream =
+                new ByteArrayInputStream(new byte[0]);
+        private int left = MAX_SUBSTREAMS;
+
+        public boolean hasMoreElements() {
+            return (left > 0);
+        }
+        public InputStream nextElement() {
+            left--;
+            return inputStream;
+        }
+    }
+}