Support large loose objects as streams

Big loose objects can now be streamed if they are over the large
object size threshold.  This prevents the JVM heap from exploding
with a very large byte array to hold the slurped file, and then
again with its uncompressed copy.

We may have slightly slowed down the simple case for small
loose objects, as the loader no longer slurps the entire thing
and decompresses in memory.  To try and keep good performance
for the very common small objects that are below 8 KiB in size,
buffers are set to 8 KiB, causing the reader to slurp most of the
file anyway.  However the data has to be copied at least once,
from the BufferedInputStream into the InflaterInputStream.

New unit tests are supplied to get nearly 100% code coverage on the
unpacked code paths, for both standard and pack style loose objects.
We tested a fair chunk of the code elsewhere, but these new tests
are better isolated to the specific branches in the code path.

Change-Id: I87b764ab1b84225e9b5619a2a55fd8eaa640e1fe
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 430 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/UnpackedObjectTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/UnpackedObjectTest.java
new file mode 100644
index 0000000000..4ca64d3eba
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/UnpackedObjectTest.java
@@ -0,0 +1,430 @@
+/*
+ * Copyright (C) 2010, Google Inc.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.storage.file;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.MessageFormat;
+import java.util.Arrays;
+import java.util.zip.DeflaterOutputStream;
+
+import org.eclipse.jgit.JGitText;
+import org.eclipse.jgit.errors.CorruptObjectException;
+import org.eclipse.jgit.errors.LargeObjectException;
+import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
+import org.eclipse.jgit.junit.TestRng;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
+import org.eclipse.jgit.lib.ObjectLoader;
+import org.eclipse.jgit.lib.ObjectStream;
+import org.eclipse.jgit.util.IO;
+
+public class UnpackedObjectTest extends LocalDiskRepositoryTestCase {
+	private TestRng rng;
+
+	private FileRepository repo;
+
+	private WindowCursor wc;
+
+	protected void setUp() throws Exception {
+		super.setUp();
+		rng = new TestRng(getName());
+		repo = createBareRepository();
+		wc = (WindowCursor) repo.newObjectReader();
+	}
+
+	protected void tearDown() throws Exception {
+		if (wc != null)
+			wc.release();
+		super.tearDown();
+	}
+
+	public void testStandardFormat_SmallObject() throws Exception {
+		final int type = Constants.OBJ_BLOB;
+		byte[] data = rng.nextBytes(300);
+		byte[] gz = compressStandardFormat(type, data);
+		ObjectId id = ObjectId.zeroId();
+
+		ObjectLoader ol = UnpackedObject.open(new ByteArrayInputStream(gz),
+				path(id), id, wc);
+		assertNotNull("created loader", ol);
+		assertEquals(type, ol.getType());
+		assertEquals(data.length, ol.getSize());
+		assertFalse("is not large", ol.isLarge());
+		assertTrue("same content", Arrays.equals(data, ol.getCachedBytes()));
+
+		ObjectStream in = ol.openStream();
+		assertNotNull("have stream", in);
+		assertEquals(type, in.getType());
+		assertEquals(data.length, in.getSize());
+		byte[] data2 = new byte[data.length];
+		IO.readFully(in, data2, 0, data.length);
+		assertTrue("same content", Arrays.equals(data2, data));
+		assertEquals("stream at EOF", -1, in.read());
+		in.close();
+	}
+
+	public void testStandardFormat_LargeObject() throws Exception {
+		final int type = Constants.OBJ_BLOB;
+		byte[] data = rng.nextBytes(UnpackedObject.LARGE_OBJECT + 5);
+		ObjectId id = new ObjectInserter.Formatter().idFor(type, data);
+		write(id, compressStandardFormat(type, data));
+
+		ObjectLoader ol;
+		{
+			FileInputStream fs = new FileInputStream(path(id));
+			try {
+				ol = UnpackedObject.open(fs, path(id), id, wc);
+			} finally {
+				fs.close();
+			}
+		}
+
+		assertNotNull("created loader", ol);
+		assertEquals(type, ol.getType());
+		assertEquals(data.length, ol.getSize());
+		assertTrue("is large", ol.isLarge());
+		try {
+			ol.getCachedBytes();
+			fail("Should have thrown LargeObjectException");
+		} catch (LargeObjectException tooBig) {
+			assertEquals(id.name(), tooBig.getMessage());
+		}
+
+		ObjectStream in = ol.openStream();
+		assertNotNull("have stream", in);
+		assertEquals(type, in.getType());
+		assertEquals(data.length, in.getSize());
+		byte[] data2 = new byte[data.length];
+		IO.readFully(in, data2, 0, data.length);
+		assertTrue("same content", Arrays.equals(data2, data));
+		assertEquals("stream at EOF", -1, in.read());
+		in.close();
+	}
+
+	public void testStandardFormat_NegativeSize() throws Exception {
+		ObjectId id = ObjectId.zeroId();
+		byte[] data = rng.nextBytes(300);
+
+		try {
+			byte[] gz = compressStandardFormat("blob", "-1", data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectNegativeSize), coe
+					.getMessage());
+		}
+	}
+
+	public void testStandardFormat_InvalidType() throws Exception {
+		ObjectId id = ObjectId.zeroId();
+		byte[] data = rng.nextBytes(300);
+
+		try {
+			byte[] gz = compressStandardFormat("not.a.type", "1", data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectInvalidType), coe
+					.getMessage());
+		}
+	}
+
+	public void testStandardFormat_NoHeader() throws Exception {
+		ObjectId id = ObjectId.zeroId();
+		byte[] data = {};
+
+		try {
+			byte[] gz = compressStandardFormat("", "", data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectNoHeader), coe
+					.getMessage());
+		}
+	}
+
+	public void testStandardFormat_GarbageAfterSize() throws Exception {
+		ObjectId id = ObjectId.zeroId();
+		byte[] data = rng.nextBytes(300);
+
+		try {
+			byte[] gz = compressStandardFormat("blob", "1foo", data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectGarbageAfterSize),
+					coe.getMessage());
+		}
+	}
+
+	public void testStandardFormat_SmallObject_CorruptZLibStream()
+			throws Exception {
+		ObjectId id = ObjectId.zeroId();
+		byte[] data = rng.nextBytes(300);
+
+		try {
+			byte[] gz = compressStandardFormat(Constants.OBJ_BLOB, data);
+			for (int i = 5; i < gz.length; i++)
+				gz[i] = 0;
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectBadStream), coe
+					.getMessage());
+		}
+	}
+
+	public void testStandardFormat_LargeObject_CorruptZLibStream()
+			throws Exception {
+		final int type = Constants.OBJ_BLOB;
+		byte[] data = rng.nextBytes(UnpackedObject.LARGE_OBJECT + 5);
+		ObjectId id = new ObjectInserter.Formatter().idFor(type, data);
+		byte[] gz = compressStandardFormat(type, data);
+		gz[gz.length - 1] = 0;
+		gz[gz.length - 2] = 0;
+
+		write(id, gz);
+
+		ObjectLoader ol;
+		{
+			FileInputStream fs = new FileInputStream(path(id));
+			try {
+				ol = UnpackedObject.open(fs, path(id), id, wc);
+			} finally {
+				fs.close();
+			}
+		}
+
+		try {
+			byte[] tmp = new byte[data.length];
+			InputStream in = ol.openStream();
+			try {
+				IO.readFully(in, tmp, 0, tmp.length);
+			} finally {
+				in.close();
+			}
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectBadStream), coe
+					.getMessage());
+		}
+	}
+
+	public void testPackFormat_SmallObject() throws Exception {
+		final int type = Constants.OBJ_BLOB;
+		byte[] data = rng.nextBytes(300);
+		byte[] gz = compressPackFormat(type, data);
+		ObjectId id = ObjectId.zeroId();
+
+		ObjectLoader ol = UnpackedObject.open(new ByteArrayInputStream(gz),
+				path(id), id, wc);
+		assertNotNull("created loader", ol);
+		assertEquals(type, ol.getType());
+		assertEquals(data.length, ol.getSize());
+		assertFalse("is not large", ol.isLarge());
+		assertTrue("same content", Arrays.equals(data, ol.getCachedBytes()));
+
+		ObjectStream in = ol.openStream();
+		assertNotNull("have stream", in);
+		assertEquals(type, in.getType());
+		assertEquals(data.length, in.getSize());
+		byte[] data2 = new byte[data.length];
+		IO.readFully(in, data2, 0, data.length);
+		assertTrue("same content", Arrays.equals(data, ol.getCachedBytes()));
+		in.close();
+	}
+
+	public void testPackFormat_LargeObject() throws Exception {
+		final int type = Constants.OBJ_BLOB;
+		byte[] data = rng.nextBytes(UnpackedObject.LARGE_OBJECT + 5);
+		ObjectId id = new ObjectInserter.Formatter().idFor(type, data);
+		write(id, compressPackFormat(type, data));
+
+		ObjectLoader ol;
+		{
+			FileInputStream fs = new FileInputStream(path(id));
+			try {
+				ol = UnpackedObject.open(fs, path(id), id, wc);
+			} finally {
+				fs.close();
+			}
+		}
+
+		assertNotNull("created loader", ol);
+		assertEquals(type, ol.getType());
+		assertEquals(data.length, ol.getSize());
+		assertTrue("is large", ol.isLarge());
+		try {
+			ol.getCachedBytes();
+			fail("Should have thrown LargeObjectException");
+		} catch (LargeObjectException tooBig) {
+			assertEquals(id.name(), tooBig.getMessage());
+		}
+
+		ObjectStream in = ol.openStream();
+		assertNotNull("have stream", in);
+		assertEquals(type, in.getType());
+		assertEquals(data.length, in.getSize());
+		byte[] data2 = new byte[data.length];
+		IO.readFully(in, data2, 0, data.length);
+		assertTrue("same content", Arrays.equals(data2, data));
+		assertEquals("stream at EOF", -1, in.read());
+		in.close();
+	}
+
+	public void testPackFormat_DeltaNotAllowed() throws Exception {
+		ObjectId id = ObjectId.zeroId();
+		byte[] data = rng.nextBytes(300);
+
+		try {
+			byte[] gz = compressPackFormat(Constants.OBJ_OFS_DELTA, data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectInvalidType), coe
+					.getMessage());
+		}
+
+		try {
+			byte[] gz = compressPackFormat(Constants.OBJ_REF_DELTA, data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectInvalidType), coe
+					.getMessage());
+		}
+
+		try {
+			byte[] gz = compressPackFormat(Constants.OBJ_TYPE_5, data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectInvalidType), coe
+					.getMessage());
+		}
+
+		try {
+			byte[] gz = compressPackFormat(Constants.OBJ_EXT, data);
+			UnpackedObject.open(new ByteArrayInputStream(gz), path(id), id, wc);
+			fail("Did not throw CorruptObjectException");
+		} catch (CorruptObjectException coe) {
+			assertEquals(MessageFormat.format(JGitText.get().objectIsCorrupt,
+					id.name(), JGitText.get().corruptObjectInvalidType), coe
+					.getMessage());
+		}
+	}
+
+	private byte[] compressStandardFormat(int type, byte[] data)
+			throws IOException {
+		String typeString = Constants.typeString(type);
+		String length = String.valueOf(data.length);
+		return compressStandardFormat(typeString, length, data);
+	}
+
+	private byte[] compressStandardFormat(String type, String length,
+			byte[] data) throws IOException {
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		DeflaterOutputStream d = new DeflaterOutputStream(out);
+		d.write(Constants.encodeASCII(type));
+		d.write(' ');
+		d.write(Constants.encodeASCII(length));
+		d.write(0);
+		d.write(data);
+		d.finish();
+		return out.toByteArray();
+	}
+
+	private byte[] compressPackFormat(int type, byte[] data) throws IOException {
+		byte[] hdr = new byte[64];
+		int rawLength = data.length;
+		int nextLength = rawLength >>> 4;
+		hdr[0] = (byte) ((nextLength > 0 ? 0x80 : 0x00) | (type << 4) | (rawLength & 0x0F));
+		rawLength = nextLength;
+		int n = 1;
+		while (rawLength > 0) {
+			nextLength >>>= 7;
+			hdr[n++] = (byte) ((nextLength > 0 ? 0x80 : 0x00) | (rawLength & 0x7F));
+			rawLength = nextLength;
+		}
+
+		final ByteArrayOutputStream out = new ByteArrayOutputStream();
+		out.write(hdr, 0, n);
+
+		DeflaterOutputStream d = new DeflaterOutputStream(out);
+		d.write(data);
+		d.finish();
+		return out.toByteArray();
+	}
+
+	private File path(ObjectId id) {
+		return repo.getObjectDatabase().fileFor(id);
+	}
+
+	private void write(ObjectId id, byte[] data) throws IOException {
+		File path = path(id);
+		path.getParentFile().mkdirs();
+		FileOutputStream out = new FileOutputStream(path);
+		try {
+			out.write(data);
+		} finally {
+			out.close();
+		}
+	}
+}