Initial JGit contribution to eclipse.org

Per CQ 3448 this is the initial contribution of the JGit project
to eclipse.org.  It is derived from the historical JGit repository
at commit 3a2dd9921c8a08740a9e02c421469e5b1a9e47cb.

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

1 files changed, 239 insertions, 0 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheIterator.java b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheIterator.java
new file mode 100644
index 0000000000..9c47187821
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheIterator.java
@@ -0,0 +1,239 @@
+/*
+ * Copyright (C) 2008-2009, Google Inc.
+ * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.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.dircache;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.FileMode;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.treewalk.AbstractTreeIterator;
+import org.eclipse.jgit.treewalk.EmptyTreeIterator;
+
+/**
+ * Iterate a {@link DirCache} as part of a <code>TreeWalk</code>.
+ * <p>
+ * This is an iterator to adapt a loaded <code>DirCache</code> instance (such as
+ * read from an existing <code>.git/index</code> file) to the tree structure
+ * used by a <code>TreeWalk</code>, making it possible for applications to walk
+ * over any combination of tree objects already in the object database, index
+ * files, or working directories.
+ *
+ * @see org.eclipse.jgit.treewalk.TreeWalk
+ */
+public class DirCacheIterator extends AbstractTreeIterator {
+	/** The cache this iterator was created to walk. */
+	protected final DirCache cache;
+
+	/** The tree this iterator is walking. */
+	private final DirCacheTree tree;
+
+	/** First position in this tree. */
+	private final int treeStart;
+
+	/** Last position in this tree. */
+	private final int treeEnd;
+
+	/** Special buffer to hold the ObjectId of {@link #currentSubtree}. */
+	private final byte[] subtreeId;
+
+	/** Index of entry within {@link #cache}. */
+	protected int ptr;
+
+	/** Next subtree to consider within {@link #tree}. */
+	private int nextSubtreePos;
+
+	/** The current file entry from {@link #cache}. */
+	protected DirCacheEntry currentEntry;
+
+	/** The subtree containing {@link #currentEntry} if this is first entry. */
+	protected DirCacheTree currentSubtree;
+
+	/**
+	 * Create a new iterator for an already loaded DirCache instance.
+	 * <p>
+	 * The iterator implementation may copy part of the cache's data during
+	 * construction, so the cache must be read in prior to creating the
+	 * iterator.
+	 *
+	 * @param dc
+	 *            the cache to walk. It must be already loaded into memory.
+	 */
+	public DirCacheIterator(final DirCache dc) {
+		cache = dc;
+		tree = dc.getCacheTree(true);
+		treeStart = 0;
+		treeEnd = tree.getEntrySpan();
+		subtreeId = new byte[Constants.OBJECT_ID_LENGTH];
+		if (!eof())
+			parseEntry();
+	}
+
+	DirCacheIterator(final DirCacheIterator p, final DirCacheTree dct) {
+		super(p, p.path, p.pathLen + 1);
+		cache = p.cache;
+		tree = dct;
+		treeStart = p.ptr;
+		treeEnd = treeStart + tree.getEntrySpan();
+		subtreeId = p.subtreeId;
+		ptr = p.ptr;
+		parseEntry();
+	}
+
+	@Override
+	public AbstractTreeIterator createSubtreeIterator(final Repository repo)
+			throws IncorrectObjectTypeException, IOException {
+		if (currentSubtree == null)
+			throw new IncorrectObjectTypeException(getEntryObjectId(),
+					Constants.TYPE_TREE);
+		return new DirCacheIterator(this, currentSubtree);
+	}
+
+	@Override
+	public EmptyTreeIterator createEmptyTreeIterator() {
+		final byte[] n = new byte[Math.max(pathLen + 1, DEFAULT_PATH_SIZE)];
+		System.arraycopy(path, 0, n, 0, pathLen);
+		n[pathLen] = '/';
+		return new EmptyTreeIterator(this, n, pathLen + 1);
+	}
+
+	@Override
+	public byte[] idBuffer() {
+		if (currentSubtree != null)
+			return subtreeId;
+		if (currentEntry != null)
+			return currentEntry.idBuffer();
+		return zeroid;
+	}
+
+	@Override
+	public int idOffset() {
+		if (currentSubtree != null)
+			return 0;
+		if (currentEntry != null)
+			return currentEntry.idOffset();
+		return 0;
+	}
+
+	@Override
+	public boolean first() {
+		return ptr == treeStart;
+	}
+
+	@Override
+	public boolean eof() {
+		return ptr == treeEnd;
+	}
+
+	@Override
+	public void next(int delta) {
+		while (--delta >= 0) {
+			if (currentSubtree != null)
+				ptr += currentSubtree.getEntrySpan();
+			else
+				ptr++;
+			if (eof())
+				break;
+			parseEntry();
+		}
+	}
+
+	@Override
+	public void back(int delta) {
+		while (--delta >= 0) {
+			if (currentSubtree != null)
+				nextSubtreePos--;
+			ptr--;
+			parseEntry();
+			if (currentSubtree != null)
+				ptr -= currentSubtree.getEntrySpan() - 1;
+		}
+	}
+
+	private void parseEntry() {
+		currentEntry = cache.getEntry(ptr);
+		final byte[] cep = currentEntry.path;
+
+		if (nextSubtreePos != tree.getChildCount()) {
+			final DirCacheTree s = tree.getChild(nextSubtreePos);
+			if (s.contains(cep, pathOffset, cep.length)) {
+				// The current position is the first file of this subtree.
+				// Use the subtree instead as the current position.
+				//
+				currentSubtree = s;
+				nextSubtreePos++;
+
+				if (s.isValid())
+					s.getObjectId().copyRawTo(subtreeId, 0);
+				else
+					Arrays.fill(subtreeId, (byte) 0);
+				mode = FileMode.TREE.getBits();
+				path = cep;
+				pathLen = pathOffset + s.nameLength();
+				return;
+			}
+		}
+
+		// The current position is a file/symlink/gitlink so we
+		// do not have a subtree located here.
+		//
+		mode = currentEntry.getRawMode();
+		path = cep;
+		pathLen = cep.length;
+		currentSubtree = null;
+	}
+
+	/**
+	 * Get the DirCacheEntry for the current file.
+	 *
+	 * @return the current cache entry, if this iterator is positioned on a
+	 *         non-tree.
+	 */
+	public DirCacheEntry getDirCacheEntry() {
+		return currentSubtree == null ? currentEntry : null;
+	}
+}