Add brute force byte array loading to ObjectLoader

Some algorithms are coded in a way that requires us to provide them
the entire object contents as a contiguous byte array.  The parsers
in RevCommit and RevTag, or our RawText objects are really good
examples of these.

Instead of duplicating this logic everywhere, lets put it into the
base ObjectLoader type.  That way the caller only needs to give us
their upper size bound, and we'll do the rest of the heavy work to
figure out if the object still fits within that bound, and get them
an array that has the complete contents.

Change-Id: Id95a7f79d2b97e39f6949370ccca2f2c9cfb1a0f
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Chris Aniszczyk <caniszczyk@gmail.com>

1 files changed, 270 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectLoaderTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectLoaderTest.java
new file mode 100644
index 0000000000..0280b4a45a
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ObjectLoaderTest.java
@@ -0,0 +1,270 @@
+/*
+ * 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.lib;
+
+import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Arrays;
+
+import junit.framework.TestCase;
+
+import org.eclipse.jgit.errors.LargeObjectException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.junit.TestRng;
+
+public class ObjectLoaderTest extends TestCase {
+	private TestRng rng;
+
+	protected void setUp() throws Exception {
+		super.setUp();
+		rng = new TestRng(getName());
+	}
+
+	public void testSmallObjectLoader() throws MissingObjectException,
+			IOException {
+		final byte[] act = rng.nextBytes(512);
+		final ObjectLoader ldr = new ObjectLoader.SmallObject(OBJ_BLOB, act);
+
+		assertEquals(OBJ_BLOB, ldr.getType());
+		assertEquals(act.length, ldr.getSize());
+		assertFalse("not is large", ldr.isLarge());
+		assertSame(act, ldr.getCachedBytes());
+		assertSame(act, ldr.getCachedBytes(1));
+		assertSame(act, ldr.getCachedBytes(Integer.MAX_VALUE));
+
+		byte[] copy = ldr.getBytes();
+		assertNotSame(act, copy);
+		assertTrue("same content", Arrays.equals(act, copy));
+
+		copy = ldr.getBytes(1);
+		assertNotSame(act, copy);
+		assertTrue("same content", Arrays.equals(act, copy));
+
+		copy = ldr.getBytes(Integer.MAX_VALUE);
+		assertNotSame(act, copy);
+		assertTrue("same content", Arrays.equals(act, copy));
+
+		ObjectStream in = ldr.openStream();
+		assertNotNull("has stream", in);
+		assertTrue("is small stream", in instanceof ObjectStream.SmallStream);
+		assertEquals(OBJ_BLOB, in.getType());
+		assertEquals(act.length, in.getSize());
+		assertEquals(act.length, in.available());
+		assertTrue("mark supported", in.markSupported());
+		copy = new byte[act.length];
+		assertEquals(act.length, in.read(copy));
+		assertEquals(0, in.available());
+		assertEquals(-1, in.read());
+		assertTrue("same content", Arrays.equals(act, copy));
+
+		ByteArrayOutputStream tmp = new ByteArrayOutputStream();
+		ldr.copyTo(tmp);
+		assertTrue("same content", Arrays.equals(act, tmp.toByteArray()));
+	}
+
+	public void testLargeObjectLoader() throws MissingObjectException,
+			IOException {
+		final byte[] act = rng.nextBytes(512);
+		final ObjectLoader ldr = new ObjectLoader() {
+			@Override
+			public byte[] getCachedBytes() throws LargeObjectException {
+				throw new LargeObjectException();
+			}
+
+			@Override
+			public long getSize() {
+				return act.length;
+			}
+
+			@Override
+			public int getType() {
+				return OBJ_BLOB;
+			}
+
+			@Override
+			public ObjectStream openStream() throws MissingObjectException,
+					IOException {
+				return new ObjectStream.Filter(getType(), act.length,
+						new ByteArrayInputStream(act));
+			}
+		};
+
+		assertEquals(OBJ_BLOB, ldr.getType());
+		assertEquals(act.length, ldr.getSize());
+		assertTrue("is large", ldr.isLarge());
+
+		try {
+			ldr.getCachedBytes();
+			fail("did not throw on getCachedBytes()");
+		} catch (LargeObjectException tooBig) {
+			// expected
+		}
+
+		try {
+			ldr.getBytes();
+			fail("did not throw on getBytes()");
+		} catch (LargeObjectException tooBig) {
+			// expected
+		}
+
+		try {
+			ldr.getCachedBytes(64);
+			fail("did not throw on getCachedBytes(64)");
+		} catch (LargeObjectException tooBig) {
+			// expected
+		}
+
+		byte[] copy = ldr.getCachedBytes(1024);
+		assertNotSame(act, copy);
+		assertTrue("same content", Arrays.equals(act, copy));
+
+		ObjectStream in = ldr.openStream();
+		assertNotNull("has stream", in);
+		assertEquals(OBJ_BLOB, in.getType());
+		assertEquals(act.length, in.getSize());
+		assertEquals(act.length, in.available());
+		assertTrue("mark supported", in.markSupported());
+		copy = new byte[act.length];
+		assertEquals(act.length, in.read(copy));
+		assertEquals(0, in.available());
+		assertEquals(-1, in.read());
+		assertTrue("same content", Arrays.equals(act, copy));
+
+		ByteArrayOutputStream tmp = new ByteArrayOutputStream();
+		ldr.copyTo(tmp);
+		assertTrue("same content", Arrays.equals(act, tmp.toByteArray()));
+	}
+
+	public void testLimitedGetCachedBytes() throws LargeObjectException,
+			MissingObjectException, IOException {
+		byte[] act = rng.nextBytes(512);
+		ObjectLoader ldr = new ObjectLoader.SmallObject(OBJ_BLOB, act) {
+			@Override
+			public boolean isLarge() {
+				return true;
+			}
+		};
+		assertTrue("is large", ldr.isLarge());
+
+		try {
+			ldr.getCachedBytes(10);
+			fail("Did not throw LargeObjectException");
+		} catch (LargeObjectException tooBig) {
+			// Expected result.
+		}
+
+		byte[] copy = ldr.getCachedBytes(512);
+		assertNotSame(act, copy);
+		assertTrue("same content", Arrays.equals(act, copy));
+
+		copy = ldr.getCachedBytes(1024);
+		assertNotSame(act, copy);
+		assertTrue("same content", Arrays.equals(act, copy));
+	}
+
+	public void testLimitedGetCachedBytesExceedsJavaLimits()
+			throws LargeObjectException, MissingObjectException, IOException {
+		ObjectLoader ldr = new ObjectLoader() {
+			@Override
+			public boolean isLarge() {
+				return true;
+			}
+
+			@Override
+			public byte[] getCachedBytes() throws LargeObjectException {
+				throw new LargeObjectException();
+			}
+
+			@Override
+			public long getSize() {
+				return Long.MAX_VALUE;
+			}
+
+			@Override
+			public int getType() {
+				return OBJ_BLOB;
+			}
+
+			@Override
+			public ObjectStream openStream() throws MissingObjectException,
+					IOException {
+				return new ObjectStream() {
+					@Override
+					public long getSize() {
+						return Long.MAX_VALUE;
+					}
+
+					@Override
+					public int getType() {
+						return OBJ_BLOB;
+					}
+
+					@Override
+					public int read() throws IOException {
+						fail("never should have reached read");
+						return -1;
+					}
+				};
+			}
+		};
+		assertTrue("is large", ldr.isLarge());
+
+		try {
+			ldr.getCachedBytes(10);
+			fail("Did not throw LargeObjectException");
+		} catch (LargeObjectException tooBig) {
+			// Expected result.
+		}
+
+		try {
+			ldr.getCachedBytes(Integer.MAX_VALUE);
+			fail("Did not throw LargeObjectException");
+		} catch (LargeObjectException tooBig) {
+			// Expected result.
+		}
+	}
+}