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- /*
- * Copyright (C) 2020, Google LLC. 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 without intermixing lines of history. */
- class TopoNonIntermixSortGenerator extends Generator {
- private static final int TOPO_QUEUED = RevWalk.TOPO_QUEUED;
-
- 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
- */
- TopoNonIntermixSortGenerator(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;
- }
- if ((c.flags & TOPO_QUEUED) == 0) {
- for (RevCommit p : c.parents) {
- p.inDegree++;
-
- if (firstParent) {
- break;
- }
- }
- }
- c.flags |= TOPO_QUEUED;
- 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.
- //
- continue;
- }
-
- if ((c.flags & TOPO_QUEUED) == 0) {
- // c is a parent that already produced or a parent that
- // was never in the priority queue and should never produce.
- //
- continue;
- }
-
- for (RevCommit p : c.parents) {
- if (--p.inDegree == 0 && (p.flags & TOPO_QUEUED) != 0) {
- // The parent has no unproduced interesting children. unpop
- // the parent so it goes right behind this child. This means
- // that this parent commit may appear in "pending" more than
- // once, but this is safe since upon the second and
- // subsequent iterations with this commit, it will no longer
- // have TOPO_QUEUED set, and thus will be skipped.
- //
- pending.unpop(p);
- }
- if (firstParent) {
- break;
- }
- }
-
- c.flags &= ~TOPO_QUEUED;
- return c;
- }
- }
- }
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