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- /*
- * 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;
-
- /** Sorts commits in topological order. */
- class TopoSortGenerator extends Generator {
- private static final int TOPO_DELAY = RevWalk.TOPO_DELAY;
-
- private final FIFORevQueue pending;
-
- private final int outputType;
-
- /**
- * Create a new sorter and completely spin the generator.
- * <p>
- * When the constructor completes the supplied generator will have no
- * commits remaining, as all of the commits will be held inside of this
- * generator's internal buffer.
- *
- * @param s
- * generator to pull all commits out of, and into this buffer.
- * @throws MissingObjectException
- * @throws IncorrectObjectTypeException
- * @throws IOException
- */
- TopoSortGenerator(Generator s) throws MissingObjectException,
- IncorrectObjectTypeException, IOException {
- pending = new FIFORevQueue();
- outputType = s.outputType() | SORT_TOPO;
- s.shareFreeList(pending);
- for (;;) {
- final RevCommit c = s.next();
- if (c == null)
- break;
- for (RevCommit p : c.parents)
- p.inDegree++;
- pending.add(c);
- }
- }
-
- @Override
- int outputType() {
- return outputType;
- }
-
- @Override
- void shareFreeList(BlockRevQueue q) {
- q.shareFreeList(pending);
- }
-
- @Override
- RevCommit next() throws MissingObjectException,
- IncorrectObjectTypeException, IOException {
- for (;;) {
- final RevCommit c = pending.next();
- if (c == null)
- return null;
-
- if (c.inDegree > 0) {
- // At least one of our children is missing. We delay
- // production until all of our children are output.
- //
- c.flags |= TOPO_DELAY;
- continue;
- }
-
- // All of our children have already produced,
- // so it is OK for us to produce now as well.
- //
- for (RevCommit p : c.parents) {
- if (--p.inDegree == 0 && (p.flags & TOPO_DELAY) != 0) {
- // This parent tried to come before us, but we are
- // his last child. unpop the parent so it goes right
- // behind this child.
- //
- p.flags &= ~TOPO_DELAY;
- pending.unpop(p);
- }
- }
- return c;
- }
- }
- }
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