123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169 |
- /*
- * 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.revwalk;
-
- import java.io.IOException;
-
- import org.eclipse.jgit.errors.IncorrectObjectTypeException;
- import org.eclipse.jgit.errors.MissingObjectException;
-
- abstract class BlockRevQueue extends AbstractRevQueue {
- protected BlockFreeList free;
-
- /** Create an empty revision queue. */
- protected BlockRevQueue() {
- free = new BlockFreeList();
- }
-
- BlockRevQueue(final Generator s) throws MissingObjectException,
- IncorrectObjectTypeException, IOException {
- free = new BlockFreeList();
- outputType = s.outputType();
- s.shareFreeList(this);
- for (;;) {
- final RevCommit c = s.next();
- if (c == null)
- break;
- add(c);
- }
- }
-
- /**
- * Reconfigure this queue to share the same free list as another.
- * <p>
- * Multiple revision queues can be connected to the same free list, making
- * it less expensive for applications to shuttle commits between them. This
- * method arranges for the receiver to take from / return to the same free
- * list as the supplied queue.
- * <p>
- * Free lists are not thread-safe. Applications must ensure that all queues
- * sharing the same free list are doing so from only a single thread.
- *
- * @param q
- * the other queue we will steal entries from.
- */
- public void shareFreeList(final BlockRevQueue q) {
- free = q.free;
- }
-
- static final class BlockFreeList {
- private Block next;
-
- Block newBlock() {
- Block b = next;
- if (b == null)
- return new Block();
- next = b.next;
- b.clear();
- return b;
- }
-
- void freeBlock(final Block b) {
- b.next = next;
- next = b;
- }
-
- void clear() {
- next = null;
- }
- }
-
- static final class Block {
- static final int BLOCK_SIZE = 256;
-
- /** Next block in our chain of blocks; null if we are the last. */
- Block next;
-
- /** Our table of queued commits. */
- final RevCommit[] commits = new RevCommit[BLOCK_SIZE];
-
- /** Next valid entry in {@link #commits}. */
- int headIndex;
-
- /** Next free entry in {@link #commits} for addition at. */
- int tailIndex;
-
- boolean isFull() {
- return tailIndex == BLOCK_SIZE;
- }
-
- boolean isEmpty() {
- return headIndex == tailIndex;
- }
-
- boolean canUnpop() {
- return headIndex > 0;
- }
-
- void add(final RevCommit c) {
- commits[tailIndex++] = c;
- }
-
- void unpop(final RevCommit c) {
- commits[--headIndex] = c;
- }
-
- RevCommit pop() {
- return commits[headIndex++];
- }
-
- RevCommit peek() {
- return commits[headIndex];
- }
-
- void clear() {
- next = null;
- headIndex = 0;
- tailIndex = 0;
- }
-
- void resetToMiddle() {
- headIndex = tailIndex = BLOCK_SIZE / 2;
- }
-
- void resetToEnd() {
- headIndex = tailIndex = BLOCK_SIZE;
- }
- }
- }
|