--- /dev/null
+/*
+ * 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.pgm.debug;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.zip.InflaterInputStream;
+
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.errors.StoredObjectRepresentationNotAvailableException;
+import org.eclipse.jgit.lib.NullProgressMonitor;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.pgm.TextBuiltin;
+import org.eclipse.jgit.revwalk.RevObject;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.storage.pack.BinaryDelta;
+import org.eclipse.jgit.storage.pack.ObjectReuseAsIs;
+import org.eclipse.jgit.storage.pack.ObjectToPack;
+import org.eclipse.jgit.storage.pack.PackOutputStream;
+import org.eclipse.jgit.storage.pack.PackWriter;
+import org.eclipse.jgit.storage.pack.StoredObjectRepresentation;
+import org.eclipse.jgit.util.TemporaryBuffer;
+import org.kohsuke.args4j.Argument;
+
+class ShowPackDelta extends TextBuiltin {
+ @Argument(index = 0)
+ private ObjectId objectId;
+
+ @Override
+ protected void run() throws Exception {
+ ObjectReader reader = db.newObjectReader();
+ RevObject obj = new RevWalk(reader).parseAny(objectId);
+ byte[] delta = getDelta(reader, obj);
+
+ // We're crossing our fingers that this will be a delta. Double
+ // check the size field in the header, it should match.
+ //
+ long size = reader.getObjectSize(obj, obj.getType());
+ try {
+ if (BinaryDelta.getResultSize(delta) != size)
+ throw die("Object " + obj.name() + " is not a delta");
+ } catch (ArrayIndexOutOfBoundsException bad) {
+ throw die("Object " + obj.name() + " is not a delta");
+ }
+
+ out.println(BinaryDelta.format(delta));
+ }
+
+ private byte[] getDelta(ObjectReader reader, RevObject obj)
+ throws IOException, MissingObjectException,
+ StoredObjectRepresentationNotAvailableException {
+ ObjectReuseAsIs asis = (ObjectReuseAsIs) reader;
+ ObjectToPack target = asis.newObjectToPack(obj);
+
+ PackWriter pw = new PackWriter(reader) {
+ @Override
+ public void select(ObjectToPack otp, StoredObjectRepresentation next) {
+ otp.select(next);
+ }
+ };
+
+ ByteArrayOutputStream buf = new ByteArrayOutputStream();
+ asis.selectObjectRepresentation(pw, target);
+ asis.copyObjectAsIs(new PackOutputStream(NullProgressMonitor.INSTANCE,
+ buf, pw), target);
+
+ // At this point the object header has no delta information,
+ // because it was output as though it were a whole object.
+ // Skip over the header and inflate.
+ //
+ byte[] bufArray = buf.toByteArray();
+ int ptr = 0;
+ while ((bufArray[ptr] & 0x80) != 0)
+ ptr++;
+ ptr++;
+
+ TemporaryBuffer.Heap raw = new TemporaryBuffer.Heap(bufArray.length);
+ InflaterInputStream inf = new InflaterInputStream(
+ new ByteArrayInputStream(bufArray, ptr, bufArray.length));
+ raw.copy(inf);
+ inf.close();
+ return raw.toByteArray();
+ }
+}
projects / jgit.git / commitdiff