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- /*
- * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> and others
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Distribution License v. 1.0 which is available at
- * https://www.eclipse.org/org/documents/edl-v10.php.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
- 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 {
- super(s.firstParent);
- pending = new FIFORevQueue(firstParent);
- 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++;
- if (firstParent) {
- break;
- }
- }
- 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);
- }
- if (firstParent) {
- break;
- }
- }
- return c;
- }
- }
- }
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