Add LfsPointerFilter TreeFilter

Add new variation of TreeFilter in order to detect LFS pointer files in
the repository.

Additionally, update LfsPointer to support the legacy version URL [1] as
described in [2], and to allow arbitrary fields in the pointer file.

[1] https://hawser.github.com/spec/v1
[2] https://github.com/git-lfs/git-lfs/blob/master/docs/spec.md

Change-Id: I621eb058619fb1b78888a54c4b60bb110a722fc3
Signed-off-by: Dariusz Luksza <dariusz@luksza.org>
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

2 files changed, 111 insertions, 3 deletions

diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java
index bbea53567f..0aee1aadde 100644
--- a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/LfsPointer.java
@@ -69,6 +69,12 @@ public class LfsPointer {
 	public static final String VERSION = "https://git-lfs.github.com/spec/v1"; //$NON-NLS-1$
 
 	/**
+	 * The version of the LfsPointer file format using legacy URL
+	 * @since 4.7
+	 */
+	public static final String VERSION_LEGACY = "https://hawser.github.com/spec/v1"; //$NON-NLS-1$
+
+	/**
 	 * The name of the hash function as used in the pointer files. This will
 	 * evaluate to "sha256"
 	 */
@@ -150,14 +156,13 @@ public class LfsPointer {
 				if (s.startsWith("#") || s.length() == 0) { //$NON-NLS-1$
 					continue;
 				} else if (s.startsWith("version") && s.length() > 8 //$NON-NLS-1$
-						&& s.substring(8).trim().equals(VERSION)) {
+						&& (s.substring(8).trim().equals(VERSION) ||
+								s.substring(8).trim().equals(VERSION_LEGACY))) {
 					versionLine = true;
 				} else if (s.startsWith("oid sha256:")) { //$NON-NLS-1$
 					id = LongObjectId.fromString(s.substring(11).trim());
 				} else if (s.startsWith("size") && s.length() > 5) { //$NON-NLS-1$
 					sz = Long.parseLong(s.substring(5).trim());
-				} else {
-					return null;
 				}
 			}
 			if (versionLine && id != null && sz > -1) {
diff --git a/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/LfsPointerFilter.java b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/LfsPointerFilter.java
new file mode 100644
index 0000000000..6f672b88f0
--- /dev/null
+++ b/org.eclipse.jgit.lfs/src/org/eclipse/jgit/lfs/lib/LfsPointerFilter.java
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2015, 2017, Dariusz Luksza <dariusz@luksza.org>
+ * 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.lfs.lib;
+
+import java.io.IOException;
+
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.lfs.LfsPointer;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectLoader;
+import org.eclipse.jgit.lib.ObjectStream;
+import org.eclipse.jgit.treewalk.TreeWalk;
+import org.eclipse.jgit.treewalk.filter.TreeFilter;
+
+/**
+ * Detects Large File pointers, as described in [1] in Git repository.
+ *
+ * [1] https://github.com/github/git-lfs/blob/master/docs/spec.md
+ *
+ * @since 4.7
+ */
+public class LfsPointerFilter extends TreeFilter {
+
+	private LfsPointer pointer;
+
+	/**
+	 * @return {@link LfsPointer} or {@code null}
+	 */
+	public LfsPointer getPointer() {
+		return pointer;
+	}
+
+	@Override
+	public boolean include(TreeWalk walk) throws MissingObjectException,
+			IncorrectObjectTypeException, IOException {
+		pointer = null;
+		if (walk.isSubtree()) {
+			return walk.isRecursive();
+		}
+		ObjectId objectId = walk.getObjectId(0);
+		ObjectLoader object = walk.getObjectReader().open(objectId);
+		if (object.getSize() > 1024) {
+			return false;
+		}
+
+		try (ObjectStream stream = object.openStream()) {
+			pointer = LfsPointer.parseLfsPointer(stream);
+			return pointer != null;
+		}
+	}
+
+	@Override
+	public boolean shouldBeRecursive() {
+		return false;
+	}
+
+	@Override
+	public TreeFilter clone() {
+		return new LfsPointerFilter();
+	}
+}