FastByteArrayInputStream returns correct count from read(byte[])

Issue: SPR-14209

Author: jhoeller

spring-core/src/main/java/org/springframework/util/FastByteArrayOutputStream.java

@@ -421,7 +421,8 @@ else if (off < 0) {
 						System.arraycopy(this.currentBuffer, this.nextIndexInCurrentBuffer, b, off, bytesToCopy);
 						this.totalBytesRead += bytesToCopy;
 						this.nextIndexInCurrentBuffer += bytesToCopy;
-						return (bytesToCopy + read(b, off + bytesToCopy, len - bytesToCopy));
+						int remaining = read(b, off + bytesToCopy, len - bytesToCopy);
+						return bytesToCopy + Math.max(remaining, 0);
 					}
 					else {
 						if (this.buffersIterator.hasNext()) {

spring-core/src/test/java/org/springframework/util/FastByteArrayOutputStreamTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,15 +16,15 @@
 
 package org.springframework.util;
 
-import static org.junit.Assert.*;
-
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
 import org.junit.Before;
 import org.junit.Test;
 
+import static org.junit.Assert.*;
+
 /**
  * Test suite for {@link FastByteArrayOutputStream}
  * @author Craig Andrews
@@ -37,21 +37,23 @@ public class FastByteArrayOutputStreamTests {
 
 	private byte[] helloBytes;
 
+
 	@Before
 	public void setUp() throws Exception {
 		this.os = new FastByteArrayOutputStream(INITIAL_CAPACITY);
 		this.helloBytes = "Hello World".getBytes("UTF-8");
 	}
 
+
 	@Test
 	public void size() throws Exception {
-		this.os.write(helloBytes);
-		assertEquals(this.os.size(), helloBytes.length);
+		this.os.write(this.helloBytes);
+		assertEquals(this.os.size(), this.helloBytes.length);
 	}
 
 	@Test
 	public void resize() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		int sizeBefore = this.os.size();
 		this.os.resize(64);
 		assertByteArrayEqualsString(this.os);
@@ -70,104 +72,118 @@ public void autoGrow() throws IOException {
 
 	@Test
 	public void write() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		assertByteArrayEqualsString(this.os);
 	}
 
 	@Test
 	public void reset() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		assertByteArrayEqualsString(this.os);
 		this.os.reset();
 		assertEquals(0, this.os.size());
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		assertByteArrayEqualsString(this.os);
 	}
 
 	@Test(expected = IOException.class)
 	public void close() throws Exception {
 		this.os.close();
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 	}
 
 	@Test
 	public void toByteArrayUnsafe() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		assertByteArrayEqualsString(this.os);
 		assertSame(this.os.toByteArrayUnsafe(), this.os.toByteArrayUnsafe());
-		assertArrayEquals(this.os.toByteArray(), helloBytes);
+		assertArrayEquals(this.os.toByteArray(), this.helloBytes);
 	}
 
 	@Test
 	public void writeTo() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		assertByteArrayEqualsString(this.os);
 		ByteArrayOutputStream baos = new ByteArrayOutputStream();
 		this.os.writeTo(baos);
-		assertArrayEquals(baos.toByteArray(), helloBytes);
+		assertArrayEquals(baos.toByteArray(), this.helloBytes);
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void failResize() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		this.os.resize(5);
 	}
 
 	@Test
 	public void getInputStream() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		assertNotNull(this.os.getInputStream());
 	}
 
 	@Test
 	public void getInputStreamAvailable() throws Exception {
-		this.os.write(helloBytes);
-		assertEquals(this.os.getInputStream().available(), helloBytes.length);
+		this.os.write(this.helloBytes);
+		assertEquals(this.os.getInputStream().available(), this.helloBytes.length);
 	}
 
 	@Test
 	public void getInputStreamRead() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		InputStream inputStream = this.os.getInputStream();
-		assertEquals(inputStream.read(), helloBytes[0]);
-		assertEquals(inputStream.read(), helloBytes[1]);
-		assertEquals(inputStream.read(), helloBytes[2]);
-		assertEquals(inputStream.read(), helloBytes[3]);
+		assertEquals(inputStream.read(), this.helloBytes[0]);
+		assertEquals(inputStream.read(), this.helloBytes[1]);
+		assertEquals(inputStream.read(), this.helloBytes[2]);
+		assertEquals(inputStream.read(), this.helloBytes[3]);
 	}
 
 	@Test
 	public void getInputStreamReadAll() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		InputStream inputStream = this.os.getInputStream();
 		byte[] actual = new byte[inputStream.available()];
 		int bytesRead = inputStream.read(actual);
-		assertEquals(bytesRead, helloBytes.length);
-		assertArrayEquals(actual, helloBytes);
+		assertEquals(this.helloBytes.length, bytesRead);
+		assertArrayEquals(this.helloBytes, actual);
+		assertEquals(0, inputStream.available());
+	}
+
+	@Test
+	public void getInputStreamReadBeyondEndOfStream() throws Exception {
+		this.os.write(this.helloBytes);
+		InputStream inputStream = os.getInputStream();
+		byte[] actual = new byte[inputStream.available() + 1];
+		int bytesRead = inputStream.read(actual);
+		assertEquals(this.helloBytes.length, bytesRead);
+		for (int i = 0; i < bytesRead; i++) {
+			assertEquals(this.helloBytes[i], actual[i]);
+		}
+		assertEquals(0, actual[this.helloBytes.length]);
 		assertEquals(0, inputStream.available());
 	}
 
 	@Test
 	public void getInputStreamSkip() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		InputStream inputStream = this.os.getInputStream();
-		assertEquals(inputStream.read(), helloBytes[0]);
+		assertEquals(inputStream.read(), this.helloBytes[0]);
 		assertEquals(inputStream.skip(1), 1);
-		assertEquals(inputStream.read(), helloBytes[2]);
-		assertEquals(helloBytes.length - 3, inputStream.available());
+		assertEquals(inputStream.read(), this.helloBytes[2]);
+		assertEquals(this.helloBytes.length - 3, inputStream.available());
 	}
 
 	@Test
 	public void getInputStreamSkipAll() throws Exception {
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		InputStream inputStream = this.os.getInputStream();
-		assertEquals(inputStream.skip(1000), helloBytes.length);
+		assertEquals(inputStream.skip(1000), this.helloBytes.length);
 		assertEquals(0, inputStream.available());
 	}
 
 	@Test
 	public void updateMessageDigest() throws Exception {
 		StringBuilder builder = new StringBuilder("\"0");
-		this.os.write(helloBytes);
+		this.os.write(this.helloBytes);
 		InputStream inputStream = this.os.getInputStream();
 		DigestUtils.appendMd5DigestAsHex(inputStream, builder);
 		builder.append("\"");
@@ -180,7 +196,7 @@ public void updateMessageDigestManyBuffers() throws Exception {
 		StringBuilder builder = new StringBuilder("\"0");
 		// filling at least one 256 buffer
 		for ( int i = 0; i < 30; i++) {
-			this.os.write(helloBytes);
+			this.os.write(this.helloBytes);
 		}
 		InputStream inputStream = this.os.getInputStream();
 		DigestUtils.appendMd5DigestAsHex(inputStream, builder);
@@ -189,8 +205,9 @@ public void updateMessageDigestManyBuffers() throws Exception {
 		assertEquals("\"06225ca1e4533354c516e74512065331d\"", actual);
 	}
 
+
 	private void assertByteArrayEqualsString(FastByteArrayOutputStream actual) {
-		assertArrayEquals(helloBytes, actual.toByteArray());
+		assertArrayEquals(this.helloBytes, actual.toByteArray());
 	}
 
 }