Merge "Refactor tree entry formatting into a common class"

3 files changed, 353 insertions, 8 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/FileMode.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/FileMode.java
index 43e4dd9c15..f295f5b72f 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/FileMode.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/FileMode.java
@@ -223,6 +223,23 @@ public abstract class FileMode {
 	}
 
 	/**
+	 * Copy this mode as a sequence of octal US-ASCII bytes.
+	 *
+	 * The mode is copied as a sequence of octal digits using the US-ASCII
+	 * character encoding. The sequence does not use a leading '0' prefix to
+	 * indicate octal notation. This method is suitable for generation of a mode
+	 * string within a GIT tree object.
+	 *
+	 * @param buf
+	 *            buffer to copy the mode to.
+	 * @param ptr
+	 *            position within {@code buf} for first digit.
+	 */
+	public void copyTo(byte[] buf, int ptr) {
+		System.arraycopy(octalBytes, 0, buf, ptr, octalBytes.length);
+	}
+
+	/**
 	 * @return the number of bytes written by {@link #copyTo(OutputStream)}.
 	 */
 	public int copyToLength() {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Tree.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Tree.java
index 2eb578b88e..06ef429974 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Tree.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Tree.java
@@ -45,7 +45,6 @@
 
 package org.eclipse.jgit.lib;
 
-import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.text.MessageFormat;
 
@@ -614,20 +613,16 @@ public class Tree extends TreeEntry implements Treeish {
 	 *             the tree cannot be loaded, or its not in a writable state.
 	 */
 	public byte[] format() throws IOException {
-		ByteArrayOutputStream o = new ByteArrayOutputStream();
+		TreeFormatter fmt = new TreeFormatter();
 		for (TreeEntry e : members()) {
 			ObjectId id = e.getId();
 			if (id == null)
 				throw new ObjectWritingException(MessageFormat.format(JGitText
 						.get().objectAtPathDoesNotHaveId, e.getFullName()));
 
-			e.getMode().copyTo(o);
-			o.write(' ');
-			o.write(e.getNameUTF8());
-			o.write(0);
-			id.copyRawTo(o);
+			fmt.append(e.getNameUTF8(), e.getMode(), id);
 		}
-		return o.toByteArray();
+		return fmt.toByteArray();
 	}
 
 	public String toString() {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/TreeFormatter.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/TreeFormatter.java
new file mode 100644
index 0000000000..e14e81f6e0
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/TreeFormatter.java
@@ -0,0 +1,333 @@
+/*
+ * 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.OBJECT_ID_LENGTH;
+import static org.eclipse.jgit.lib.Constants.OBJ_TREE;
+import static org.eclipse.jgit.lib.Constants.encode;
+import static org.eclipse.jgit.lib.FileMode.GITLINK;
+import static org.eclipse.jgit.lib.FileMode.REGULAR_FILE;
+import static org.eclipse.jgit.lib.FileMode.TREE;
+
+import java.io.IOException;
+
+import org.eclipse.jgit.revwalk.RevBlob;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.util.TemporaryBuffer;
+
+/**
+ * Mutable formatter to construct a single tree object.
+ *
+ * This formatter does not process subtrees. Callers must handle creating each
+ * subtree on their own.
+ *
+ * To maintain good performance for bulk operations, this formatter does not
+ * validate its input. Callers are responsible for ensuring the resulting tree
+ * object is correctly well formed by writing entries in the correct order.
+ */
+public class TreeFormatter {
+	/**
+	 * Compute the size of a tree entry record.
+	 *
+	 * This method can be used to estimate the correct size of a tree prior to
+	 * allocating a formatter. Getting the size correct at allocation time
+	 * ensures the internal buffer is sized correctly, reducing copying.
+	 *
+	 * @param mode
+	 *            the mode the entry will have.
+	 * @param nameLen
+	 *            the length of the name, in bytes.
+	 * @return the length of the record.
+	 */
+	public static int entrySize(FileMode mode, int nameLen) {
+		return mode.copyToLength() + nameLen + OBJECT_ID_LENGTH + 2;
+	}
+
+	private byte[] buf;
+
+	private int ptr;
+
+	private TemporaryBuffer.Heap overflowBuffer;
+
+	/** Create an empty formatter with a default buffer size. */
+	public TreeFormatter() {
+		this(8192);
+	}
+
+	/**
+	 * Create an empty formatter with the specified buffer size.
+	 *
+	 * @param size
+	 *            estimated size of the tree, in bytes. Callers can use
+	 *            {@link #entrySize(FileMode, int)} to estimate the size of each
+	 *            entry in advance of allocating the formatter.
+	 */
+	public TreeFormatter(int size) {
+		buf = new byte[size];
+	}
+
+	/**
+	 * Add a link to a submodule commit, mode is {@link #GITLINK}.
+	 *
+	 * @param name
+	 *            name of the entry.
+	 * @param commit
+	 *            the ObjectId to store in this entry.
+	 */
+	public void append(String name, RevCommit commit) {
+		append(name, GITLINK, commit);
+	}
+
+	/**
+	 * Add a subtree, mode is {@link #TREE}.
+	 *
+	 * @param name
+	 *            name of the entry.
+	 * @param tree
+	 *            the ObjectId to store in this entry.
+	 */
+	public void append(String name, RevTree tree) {
+		append(name, TREE, tree);
+	}
+
+	/**
+	 * Add a regular file, mode is {@link #REGULAR_FILE}.
+	 *
+	 * @param name
+	 *            name of the entry.
+	 * @param blob
+	 *            the ObjectId to store in this entry.
+	 */
+	public void append(String name, RevBlob blob) {
+		append(name, REGULAR_FILE, blob);
+	}
+
+	/**
+	 * Append any entry to the tree.
+	 *
+	 * @param name
+	 *            name of the entry.
+	 * @param mode
+	 *            mode describing the treatment of {@code id}.
+	 * @param id
+	 *            the ObjectId to store in this entry.
+	 */
+	public void append(String name, FileMode mode, AnyObjectId id) {
+		append(encode(name), mode, id);
+	}
+
+	/**
+	 * Append any entry to the tree.
+	 *
+	 * @param name
+	 *            name of the entry. The name should be UTF-8 encoded, but file
+	 *            name encoding is not a well defined concept in Git.
+	 * @param mode
+	 *            mode describing the treatment of {@code id}.
+	 * @param id
+	 *            the ObjectId to store in this entry.
+	 */
+	public void append(byte[] name, FileMode mode, AnyObjectId id) {
+		append(name, 0, name.length, mode, id);
+	}
+
+	/**
+	 * Append any entry to the tree.
+	 *
+	 * @param nameBuf
+	 *            buffer holding the name of the entry. The name should be UTF-8
+	 *            encoded, but file name encoding is not a well defined concept
+	 *            in Git.
+	 * @param namePos
+	 *            first position within {@code nameBuf} of the name data.
+	 * @param nameLen
+	 *            number of bytes from {@code nameBuf} to use as the name.
+	 * @param mode
+	 *            mode describing the treatment of {@code id}.
+	 * @param id
+	 *            the ObjectId to store in this entry.
+	 */
+	public void append(byte[] nameBuf, int namePos, int nameLen, FileMode mode,
+			AnyObjectId id) {
+		if (fmtBuf(nameBuf, namePos, nameLen, mode)) {
+			id.copyRawTo(buf, ptr);
+			ptr += OBJECT_ID_LENGTH;
+
+		} else {
+			try {
+				fmtOverflowBuffer(nameBuf, namePos, nameLen, mode);
+				id.copyRawTo(overflowBuffer);
+			} catch (IOException badBuffer) {
+				// This should never occur.
+				throw new RuntimeException(badBuffer);
+			}
+		}
+	}
+
+	/**
+	 * Append any entry to the tree.
+	 *
+	 * @param nameBuf
+	 *            buffer holding the name of the entry. The name should be UTF-8
+	 *            encoded, but file name encoding is not a well defined concept
+	 *            in Git.
+	 * @param namePos
+	 *            first position within {@code nameBuf} of the name data.
+	 * @param nameLen
+	 *            number of bytes from {@code nameBuf} to use as the name.
+	 * @param mode
+	 *            mode describing the treatment of {@code id}.
+	 * @param idBuf
+	 *            buffer holding the raw ObjectId of the entry.
+	 * @param idPos
+	 *            first position within {@code idBuf} to copy the id from.
+	 */
+	public void append(byte[] nameBuf, int namePos, int nameLen, FileMode mode,
+			byte[] idBuf, int idPos) {
+		if (fmtBuf(nameBuf, namePos, nameLen, mode)) {
+			System.arraycopy(idBuf, idPos, buf, ptr, OBJECT_ID_LENGTH);
+			ptr += OBJECT_ID_LENGTH;
+
+		} else {
+			try {
+				fmtOverflowBuffer(nameBuf, namePos, nameLen, mode);
+				overflowBuffer.write(idBuf, idPos, OBJECT_ID_LENGTH);
+			} catch (IOException badBuffer) {
+				// This should never occur.
+				throw new RuntimeException(badBuffer);
+			}
+		}
+	}
+
+	private boolean fmtBuf(byte[] nameBuf, int namePos, int nameLen,
+			FileMode mode) {
+		if (buf == null || buf.length < ptr + entrySize(mode, nameLen))
+			return false;
+
+		mode.copyTo(buf, ptr);
+		ptr += mode.copyToLength();
+		buf[ptr++] = ' ';
+
+		System.arraycopy(nameBuf, namePos, buf, ptr, nameLen);
+		ptr += nameLen;
+		buf[ptr++] = 0;
+		return true;
+	}
+
+	private void fmtOverflowBuffer(byte[] nameBuf, int namePos, int nameLen,
+			FileMode mode) throws IOException {
+		if (buf != null) {
+			overflowBuffer = new TemporaryBuffer.Heap(Integer.MAX_VALUE);
+			overflowBuffer.write(buf, 0, ptr);
+			buf = null;
+		}
+
+		mode.copyTo(overflowBuffer);
+		overflowBuffer.write((byte) ' ');
+		overflowBuffer.write(nameBuf, namePos, nameLen);
+		overflowBuffer.write((byte) 0);
+	}
+
+	/**
+	 * Compute the current tree's ObjectId.
+	 *
+	 * @return computed ObjectId of the tree
+	 */
+	public ObjectId getTreeId() {
+		final ObjectInserter.Formatter fmt = new ObjectInserter.Formatter();
+		if (buf != null)
+			return fmt.idFor(OBJ_TREE, buf, 0, ptr);
+
+		try {
+			final long len = overflowBuffer.length();
+			return fmt.idFor(OBJ_TREE, len, overflowBuffer.openInputStream());
+		} catch (IOException err) {
+			// This should never happen, its read failure on a byte array.
+			throw new RuntimeException(err);
+		}
+	}
+
+	/**
+	 * Insert this tree and obtain its ObjectId.
+	 *
+	 * @param ins
+	 *            the inserter to store the tree.
+	 * @return computed ObjectId of the tree
+	 * @throws IOException
+	 *             the tree could not be stored.
+	 */
+	public ObjectId insert(ObjectInserter ins) throws IOException {
+		if (buf != null)
+			return ins.insert(OBJ_TREE, buf, 0, ptr);
+
+		final long len = overflowBuffer.length();
+		return ins.insert(OBJ_TREE, len, overflowBuffer.openInputStream());
+	}
+
+	/**
+	 * Copy this formatter's buffer into a byte array.
+	 *
+	 * This method is not efficient, as it needs to create a copy of the
+	 * internal buffer in order to supply an array of the correct size to the
+	 * caller. If the buffer is just to pass to an ObjectInserter, consider
+	 * using {@link #insert(ObjectInserter)} instead.
+	 *
+	 * @return a copy of this formatter's buffer.
+	 */
+	public byte[] toByteArray() {
+		if (buf != null) {
+			byte[] r = new byte[ptr];
+			System.arraycopy(buf, 0, r, 0, ptr);
+			return r;
+		}
+
+		try {
+			return overflowBuffer.toByteArray();
+		} catch (IOException err) {
+			// This should never happen, its read failure on a byte array.
+			throw new RuntimeException(err);
+		}
+	}
+}