[PATCH JGIT 5/5] Treat gitlink tree entries similar to symlink tree entries

[Jonas Fonseca <fonseca@diku.dk>]

Adds minimal support for gitlinks, based on the existing code for
handling symlinks. The goal is to avoid exceptions when reading trees
with gitlinks.

Signed-off-by: Jonas Fonseca <fonseca@diku.dk>
---
 .../jgit/errors/GitlinksNotSupportedException.java |   58 +++++++++++++
 .../src/org/spearce/jgit/lib/ForceModified.java    |    4 +
 .../src/org/spearce/jgit/lib/GitlinkTreeEntry.java |   85 ++++++++++++++++++++
 .../src/org/spearce/jgit/lib/TreeVisitor.java      |    8 ++
 .../src/org/spearce/jgit/lib/WriteTree.java        |    7 ++
 5 files changed, 162 insertions(+), 0 deletions(-)
 create mode 100644 org.spearce.jgit/src/org/spearce/jgit/errors/GitlinksNotSupportedException.java
 create mode 100644 org.spearce.jgit/src/org/spearce/jgit/lib/GitlinkTreeEntry.java

diff --git a/org.spearce.jgit/src/org/spearce/jgit/errors/GitlinksNotSupportedException.java b/org.spearce.jgit/src/org/spearce/jgit/errors/GitlinksNotSupportedException.java
new file mode 100644
index 0000000..8f8883f
--- /dev/null
+++ b/org.spearce.jgit/src/org/spearce/jgit/errors/GitlinksNotSupportedException.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
+ * Copyright (C) 2007, Shawn O. Pearce <spearce@spearce.org>
+ *
+ * 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 Git Development Community 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.spearce.jgit.errors;
+
+import java.io.IOException;
+
+/**
+ * An exception thrown when a gitlink entry is found and cannot be
+ * handled.
+ */
+public class GitlinksNotSupportedException extends IOException {
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * Construct a GitlinksNotSupportedException for the specified link
+	 *
+	 * @param s name of link in tree or workdir
+	 */
+	public GitlinksNotSupportedException(final String s) {
+		super(s);
+	}
+}
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/ForceModified.java b/org.spearce.jgit/src/org/spearce/jgit/lib/ForceModified.java
index 6d38068..9c94e13 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/ForceModified.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/ForceModified.java
@@ -61,4 +61,8 @@ public void visitSymlink(final SymlinkTreeEntry s) throws IOException {
 		// Eclipse
 		// and Pure Java does not know what to do about symbolic links.
 	}
+
+	public void visitGitlink(GitlinkTreeEntry s) throws IOException {
+		// TODO: handle gitlinks.
+	}
 }
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/GitlinkTreeEntry.java b/org.spearce.jgit/src/org/spearce/jgit/lib/GitlinkTreeEntry.java
new file mode 100644
index 0000000..babbc26
--- /dev/null
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/GitlinkTreeEntry.java
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
+ * Copyright (C) 2007, Shawn O. Pearce <spearce@spearce.org>
+ *
+ * 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 Git Development Community 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.spearce.jgit.lib;
+
+import java.io.IOException;
+
+/**
+ * A tree entry representing a symbolic link.
+ *
+ * Note. Java cannot really handle these as file system objects.
+ */
+public class GitlinkTreeEntry extends TreeEntry {
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * Construct a {@link SymlinkTreeEntry} with the specified name and SHA-1 in
+	 * the specified parent
+	 *
+	 * @param parent
+	 * @param id
+	 * @param nameUTF8
+	 */
+	public GitlinkTreeEntry(final Tree parent, final ObjectId id,
+			final byte[] nameUTF8) {
+		super(parent, id, nameUTF8);
+	}
+
+	public FileMode getMode() {
+		return FileMode.GITLINK;
+	}
+
+	public void accept(final TreeVisitor tv, final int flags)
+			throws IOException {
+		if ((MODIFIED_ONLY & flags) == MODIFIED_ONLY && !isModified()) {
+			return;
+		}
+
+		tv.visitGitlink(this);
+	}
+
+	@Override
+	public String toString() {
+		final StringBuffer r = new StringBuffer();
+		r.append(ObjectId.toString(getId()));
+		r.append(" G ");
+		r.append(getFullName());
+		return r.toString();
+	}
+}
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/TreeVisitor.java b/org.spearce.jgit/src/org/spearce/jgit/lib/TreeVisitor.java
index 78a6c22..8293c24 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/TreeVisitor.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/TreeVisitor.java
@@ -77,4 +77,12 @@
 	 * @throws IOException
 	 */
 	public void visitSymlink(final SymlinkTreeEntry s) throws IOException;
+
+	/**
+	 * Visit to a gitlink.
+	 *
+	 * @param s Gitlink entry
+	 * @throws IOException
+	 */
+	public void visitGitlink(final GitlinkTreeEntry s) throws IOException;
 }
diff --git a/org.spearce.jgit/src/org/spearce/jgit/lib/WriteTree.java b/org.spearce.jgit/src/org/spearce/jgit/lib/WriteTree.java
index 9841678..d6725a9 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/lib/WriteTree.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/lib/WriteTree.java
@@ -41,6 +41,7 @@
 import java.io.File;
 import java.io.IOException;
 
+import org.spearce.jgit.errors.GitlinksNotSupportedException;
 import org.spearce.jgit.errors.SymlinksNotSupportedException;
 
 /**
@@ -78,4 +79,10 @@ public void endVisitTree(final Tree t) throws IOException {
 		super.endVisitTree(t);
 		t.setId(ow.writeTree(t));
 	}
+
+	public void visitGitlink(GitlinkTreeEntry s) throws IOException {
+		if (s.isModified()) {
+			throw new GitlinksNotSupportedException(s.getFullName());
+		}
+	}
 }
-- 
1.6.4.rc3.195.g2b05f