8029689: (spec) Reader.read(char[], int, int) throws unspecified IndexOutOfBoundsException

Reviewed-by: chegar, lancea

jdk/src/java.base/share/classes/java/io/BufferedReader.java

@@ -272,6 +272,7 @@ public class BufferedReader extends Reader {
      *             stream has been reached
      *
      * @exception  IOException  If an I/O error occurs
+     * @exception  IndexOutOfBoundsException {@inheritDoc}
      */
     public int read(char cbuf[], int off, int len) throws IOException {
         synchronized (lock) {

jdk/src/java.base/share/classes/java/io/CharArrayReader.java

@@ -116,6 +116,7 @@ public class CharArrayReader extends Reader {
      *          the end of the stream has been reached
      *
      * @exception   IOException  If an I/O error occurs
+     * @exception   IndexOutOfBoundsException {@inheritDoc}
      */
     public int read(char b[], int off, int len) throws IOException {
         synchronized (lock) {

jdk/src/java.base/share/classes/java/io/FilterReader.java

@@ -69,6 +69,7 @@ public abstract class FilterReader extends Reader {
      * Reads characters into a portion of an array.
      *
      * @exception  IOException  If an I/O error occurs
+     * @exception  IndexOutOfBoundsException {@inheritDoc}
      */
     public int read(char cbuf[], int off, int len) throws IOException {
         return in.read(cbuf, off, len);

jdk/src/java.base/share/classes/java/io/InputStreamReader.java

@@ -179,6 +179,7 @@ public class InputStreamReader extends Reader {
      *             stream has been reached
      *
      * @exception  IOException  If an I/O error occurs
+     * @exception  IndexOutOfBoundsException {@inheritDoc}
      */
     public int read(char cbuf[], int offset, int length) throws IOException {
         return sd.read(cbuf, offset, length);

jdk/src/java.base/share/classes/java/io/LineNumberReader.java

@@ -159,6 +159,8 @@ public class LineNumberReader extends BufferedReader {
      *
      * @throws  IOException
      *          If an I/O error occurs
+     *
+     * @throws  IndexOutOfBoundsException {@inheritDoc}
      */
     @SuppressWarnings("fallthrough")
     public int read(char cbuf[], int off, int len) throws IOException {

jdk/src/java.base/share/classes/java/io/PipedReader.java

@@ -286,6 +286,7 @@ public class PipedReader extends Reader {
      *                  <a href=PipedInputStream.html#BROKEN> <code>broken</code></a>,
      *                  {@link #connect(java.io.PipedWriter) unconnected}, closed,
      *                  or an I/O error occurs.
+     * @exception  IndexOutOfBoundsException {@inheritDoc}
      */
     public synchronized int read(char cbuf[], int off, int len)  throws IOException {
         if (!connected) {

jdk/src/java.base/share/classes/java/io/PushbackReader.java

@@ -102,6 +102,7 @@ public class PushbackReader extends FilterReader {
      *             stream has been reached
      *
      * @exception  IOException  If an I/O error occurs
+     * @exception  IndexOutOfBoundsException {@inheritDoc}
      */
     public int read(char cbuf[], int off, int len) throws IOException {
         synchronized (lock) {

jdk/src/java.base/share/classes/java/io/Reader.java

@@ -153,6 +153,9 @@ public abstract class Reader implements Readable, Closeable {
      *             stream has been reached
      *
      * @exception  IOException  If an I/O error occurs
+     * @exception  IndexOutOfBoundsException
+     *             If {@code off} is negative, or {@code len} is negative,
+     *             or {@code len} is greater than {@code cbuf.length - off}
      */
     abstract public int read(char cbuf[], int off, int len) throws IOException;
 

jdk/src/java.base/share/classes/java/io/StringReader.java

@@ -84,6 +84,7 @@ public class StringReader extends Reader {
      *             stream has been reached
      *
      * @exception  IOException  If an I/O error occurs
+     * @exception  IndexOutOfBoundsException {@inheritDoc}
      */
     public int read(char cbuf[], int off, int len) throws IOException {
         synchronized (lock) {

jdk/test/java/io/Reader/ReaderBulkReadContract.java

@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2015, 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.
+ */
+
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
+import java.io.CharArrayReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.LineNumberReader;
+import java.io.PipedReader;
+import java.io.PipedWriter;
+import java.io.PushbackReader;
+import java.io.Reader;
+import java.io.StringReader;
+import java.io.UncheckedIOException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+
+import static java.lang.String.format;
+
+/*
+ * @test
+ * @bug 8029689
+ * @summary checks the bounds part of the contract of java.io.Reader.read(char[], int, int):
+ *
+ *              0 <= off <= off+len <= cbuf.length
+ *
+ *          for publicly exported subtypes of java.io.Reader
+ */
+public class ReaderBulkReadContract {
+
+    public static void main(String[] args) throws IOException {
+        ReaderBulkReadContract t = new ReaderBulkReadContract();
+        t.test();
+    }
+
+    private void test() throws IOException {
+        Iterator<Object[]> args = args();
+        while (args.hasNext()) {
+            Object[] a = args.next();
+            Reader r = (Reader) a[0];
+            int size = (int) a[1];
+            int off = (int) a[2];
+            int len = (int) a[3];
+            try {
+                read(r, size, off, len);
+            } finally {
+                r.close();
+            }
+        }
+    }
+
+    private Iterator<Object[]> args() {
+
+        Integer[] lens = {Integer.MIN_VALUE, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, Integer.MAX_VALUE};
+        Integer[] offs = {Integer.MIN_VALUE, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, Integer.MAX_VALUE};
+        Integer[] sizes = {0, 1, 2, 3, 4, 5};
+        String[] contents = {"", "a", "ab"};
+
+        List<Function<String, Reader>> fs = Arrays.asList(
+                (String s) -> new BufferedReader(new StringReader(s)),
+                (String s) -> new LineNumberReader(new StringReader(s)),
+                (String s) -> new CharArrayReader(s.toCharArray()),
+                (String s) -> new InputStreamReader(new ByteArrayInputStream(s.getBytes())),
+                (String s) -> newFileReader(s),
+                (String s) -> new PushbackReader(new StringReader(s)),
+                (String s) -> newPipedReader(s),
+                (String s) -> new StringReader(s)
+        );
+
+        // The easiest way to produce a cartesian product from a small fixed number of sets
+        List<Object[]> tuples = Collections.synchronizedList(new LinkedList<>());
+        for (Integer len : lens)
+            for (Integer off : offs)
+                for (String s : contents)
+                    for (Integer size : sizes)
+                        for (Function<String, Reader> f : fs)
+                            tuples.add(new Object[]{f.apply(s), size, off, len});
+
+        return tuples.iterator();
+    }
+
+    private void read(Reader r, int size, int off, int len) throws IOException {
+        IndexOutOfBoundsException ex = null;
+        try {
+            r.read(new char[size], off, len);
+        } catch (IndexOutOfBoundsException e) {
+            ex = e;
+        }
+
+        boolean incorrectBounds = off < 0 || len < 0 || len > size - off;
+        boolean exceptionThrown = ex != null;
+
+        if (incorrectBounds != exceptionThrown) { // incorrectBounds iff exceptionThrown
+            throw new AssertionError(format("r=%s, size=%s, off=%s, len=%s, incorrectBounds=%s, exceptionThrown=%s",
+                    r, size, off, len, incorrectBounds, exceptionThrown));
+        }
+    }
+
+    private static PipedReader newPipedReader(String contents) {
+        try (PipedWriter w = new PipedWriter()) {
+            PipedReader r = new PipedReader(w);
+            w.write(contents);
+            return r;
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    private FileReader newFileReader(String contents) {
+        try {
+            // To not create an enormous amount of files
+            File f = cache.computeIfAbsent(contents,
+                    ReaderBulkReadContract::createTempFileWithContents);
+            return new FileReader(f);
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    private static File createTempFileWithContents(String contents) {
+        try {
+            File file = File.createTempFile("ReaderContract", "");
+            try (FileWriter w = new FileWriter(file)) {
+                w.write(contents);
+            }
+            return file;
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    //
+    // To avoid myriads of tiny files a cache is used.
+    // ConcurrentHashMap.computeIfAbsent promises a crucial thing:
+    //
+    // ...The entire method invocation is performed atomically, so the
+    // function is applied at most once per key...
+    //  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    //
+    private final ConcurrentHashMap<String, File> cache = new ConcurrentHashMap<>();
+}