/*
    * Copyright (C) 2008-2009, Google Inc. and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  
  package org.eclipse.jgit.util;
  
  import static org.eclipse.jgit.junit.JGitTestUtil.getName;
  import static org.junit.Assert.assertArrayEquals;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNotNull;
  import static org.junit.Assert.fail;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.eclipse.jgit.junit.TestRng;
  import org.eclipse.jgit.util.TemporaryBuffer.Block;
  import org.junit.Test;
  
  public class TemporaryBufferTest {
  	@Test
  	public void testEmpty() throws IOException {
  		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
  		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
  		try {
  			b.close();
  			assertEquals(0, b.length());
  			final byte[] r = b.toByteArray();
  			assertNotNull(r);
  			assertEquals(0, r.length);
  		} finally {
  			b.destroy();
  		}
  	}
  
  	@Test
  	public void testOneByte() throws IOException {
  		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
  		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
  		final byte test = (byte) new TestRng(getName()).nextInt();
  		try {
  			b.write(test);
  			b.close();
  			assertEquals(1, b.length());
  			{
  				final byte[] r = b.toByteArray();
  				assertNotNull(r);
  				assertEquals(1, r.length);
  				assertEquals(test, r[0]);
  			}
  			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
  				b.writeTo(o, null);
  				final byte[] r = o.toByteArray();
  				assertEquals(1, r.length);
  				assertEquals(test, r[0]);
  			}
  		} finally {
  			b.destroy();
  		}
  	}
  
  	@Test
  	public void testOneBlock_BulkWrite() throws IOException {
  		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
  		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
  		final byte[] test = new TestRng(getName())
  				.nextBytes(TemporaryBuffer.Block.SZ);
  		try {
  			b.write(test, 0, 2);
  			b.write(test, 2, 4);
  			b.write(test, 6, test.length - 6 - 2);
  			b.write(test, test.length - 2, 2);
  			b.close();
  			assertEquals(test.length, b.length());
  			{
  				final byte[] r = b.toByteArray();
  				assertNotNull(r);
  				assertEquals(test.length, r.length);
  				assertArrayEquals(test, r);
  			}
  			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
  				b.writeTo(o, null);
  				final byte[] r = o.toByteArray();
  				assertEquals(test.length, r.length);
  				assertArrayEquals(test, r);
  			}
  		} finally {
  			b.destroy();
  		}
  	}
  
 	@Test
 	public void testOneBlockAndHalf_BulkWrite() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final byte[] test = new TestRng(getName())
 				.nextBytes(TemporaryBuffer.Block.SZ * 3 / 2);
 		try {
 			b.write(test, 0, 2);
 			b.write(test, 2, 4);
 			b.write(test, 6, test.length - 6 - 2);
 			b.write(test, test.length - 2, 2);
 			b.close();
 			assertEquals(test.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testOneBlockAndHalf_SingleWrite() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final byte[] test = new TestRng(getName())
 				.nextBytes(TemporaryBuffer.Block.SZ * 3 / 2);
 		try {
 			for (int i = 0; i < test.length; i++)
 				b.write(test[i]);
 			b.close();
 			assertEquals(test.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testOneBlockAndHalf_Copy() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final byte[] test = new TestRng(getName())
 				.nextBytes(TemporaryBuffer.Block.SZ * 3 / 2);
 		try {
 			final ByteArrayInputStream in = new ByteArrayInputStream(test);
 			b.write(in.read());
 			b.copy(in);
 			b.close();
 			assertEquals(test.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testLarge_SingleWrite() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final byte[] test = new TestRng(getName())
 				.nextBytes(TemporaryBuffer.DEFAULT_IN_CORE_LIMIT * 3);
 		try {
 			b.write(test);
 			b.close();
 			assertEquals(test.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testInCoreInputStream() throws IOException {
 		final int cnt = 256;
 		final byte[] test = new TestRng(getName()).nextBytes(cnt);
 		try (TemporaryBuffer.Heap b = new TemporaryBuffer.Heap(cnt + 4)) {
 			b.write(test);
 			InputStream in = b.openInputStream();
 			byte[] act = new byte[cnt];
 			IO.readFully(in, act, 0, cnt);
 			assertArrayEquals(test, act);
 		}
 	}
 
 	@Test
 	public void testInCoreLimit_SwitchOnAppendByte() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final byte[] test = new TestRng(getName())
 				.nextBytes(TemporaryBuffer.DEFAULT_IN_CORE_LIMIT + 1);
 		try {
 			b.write(test, 0, test.length - 1);
 			b.write(test[test.length - 1]);
 			b.close();
 			assertEquals(test.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testInCoreLimit_SwitchBeforeAppendByte() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final byte[] test = new TestRng(getName())
 				.nextBytes(TemporaryBuffer.DEFAULT_IN_CORE_LIMIT * 3);
 		try {
 			b.write(test, 0, test.length - 1);
 			b.write(test[test.length - 1]);
 			b.close();
 			assertEquals(test.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testInCoreLimit_SwitchOnCopy() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final byte[] test = new TestRng(getName())
 				.nextBytes(TemporaryBuffer.DEFAULT_IN_CORE_LIMIT * 2);
 		try {
 			final ByteArrayInputStream in = new ByteArrayInputStream(test,
 					TemporaryBuffer.DEFAULT_IN_CORE_LIMIT, test.length
 							- TemporaryBuffer.DEFAULT_IN_CORE_LIMIT);
 			b.write(test, 0, TemporaryBuffer.DEFAULT_IN_CORE_LIMIT);
 			b.copy(in);
 			b.close();
 			assertEquals(test.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(test.length, r.length);
 				assertArrayEquals(test, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testDestroyWhileOpen() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		try {
 			b.write(new TestRng(getName())
 					.nextBytes(TemporaryBuffer.DEFAULT_IN_CORE_LIMIT * 2));
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testRandomWrites() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		final TemporaryBuffer b = new TemporaryBuffer.LocalFile(null);
 		final TestRng rng = new TestRng(getName());
 		final int max = TemporaryBuffer.DEFAULT_IN_CORE_LIMIT * 2;
 		final byte[] expect = new byte[max];
 		try {
 			int written = 0;
 			boolean onebyte = true;
 			while (written < max) {
 				if (onebyte) {
 					final byte v = (byte) rng.nextInt();
 					b.write(v);
 					expect[written++] = v;
 				} else {
 					final int len = Math
 							.min(rng.nextInt() & 127, max - written);
 					final byte[] tmp = rng.nextBytes(len);
 					b.write(tmp, 0, len);
 					System.arraycopy(tmp, 0, expect, written, len);
 					written += len;
 				}
 				onebyte = !onebyte;
 			}
 			assertEquals(expect.length, written);
 			b.close();
 
 			assertEquals(expect.length, b.length());
 			{
 				final byte[] r = b.toByteArray();
 				assertNotNull(r);
 				assertEquals(expect.length, r.length);
 				assertArrayEquals(expect, r);
 			}
 			try (ByteArrayOutputStream o = new ByteArrayOutputStream()) {
 				b.writeTo(o, null);
 				final byte[] r = o.toByteArray();
 				assertEquals(expect.length, r.length);
 				assertArrayEquals(expect, r);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 
 	@Test
 	public void testHeap() throws IOException {
 		try (TemporaryBuffer b = new TemporaryBuffer.Heap(2 * 8 * 1024)) {
 			final byte[] r = new byte[8 * 1024];
 			b.write(r);
 			b.write(r);
 			try {
 				b.write(1);
 				fail("accepted too many bytes of data");
 			} catch (IOException e) {
 				assertEquals("In-memory buffer limit exceeded", e.getMessage());
 			}
 		}
 	}
 
 	@Test
 	public void testHeapWithEstimatedSize() throws IOException {
 		int sz = 2 * Block.SZ;
 		try (TemporaryBuffer b = new TemporaryBuffer.Heap(sz / 2, sz)) {
 			for (int i = 0; i < sz; i++) {
 				b.write('x');
 			}
 			try {
 				b.write(1);
 				fail("accepted too many bytes of data");
 			} catch (IOException e) {
 				assertEquals("In-memory buffer limit exceeded", e.getMessage());
 			}
 
 			try (InputStream in = b.openInputStream()) {
 				for (int i = 0; i < sz; i++) {
 					assertEquals('x', in.read());
 				}
 				assertEquals(-1, in.read());
 			}
 		}
 	}
 
 	@Test
 	public void testHeapToByteArrayWithLimit() throws IOException {
 		int sz = 2 * Block.SZ;
 		try (TemporaryBuffer b = new TemporaryBuffer.Heap(sz / 2, sz)) {
 			for (int i = 0; i < sz; i++) {
 				b.write('a' + i % 26);
 			}
 			byte[] prefix = b.toByteArray(5);
 			assertEquals(5, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 			prefix = b.toByteArray(Block.SZ + 37);
 			assertEquals(Block.SZ + 37, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 			prefix = b.toByteArray(sz);
 			assertEquals(sz, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 			prefix = b.toByteArray(sz + 37);
 			assertEquals(sz, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 		}
 	}
 
 	@Test
 	public void testFileToByteArrayWithLimit() throws IOException {
 		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
 		TemporaryBuffer b = new TemporaryBuffer.LocalFile(null, 2 * Block.SZ);
 		int sz = 3 * Block.SZ;
 		try {
 			for (int i = 0; i < sz; i++) {
 				b.write('a' + i % 26);
 			}
 			b.close();
 			byte[] prefix = b.toByteArray(5);
 			assertEquals(5, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 			prefix = b.toByteArray(Block.SZ + 37);
 			assertEquals(Block.SZ + 37, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 			prefix = b.toByteArray(sz);
 			assertEquals(sz, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 			prefix = b.toByteArray(sz + 37);
 			assertEquals(sz, prefix.length);
 			for (int i = 0; i < prefix.length; i++) {
 				assertEquals('a' + i % 26, prefix[i]);
 			}
 		} finally {
 			b.destroy();
 		}
 	}
 }