1 files changed, 150 insertions, 0 deletions
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/DateRevPriorityQueue.java b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/DateRevPriorityQueue.java
new file mode 100644
index 0000000000..233dd64a3c
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/DateRevPriorityQueue.java
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2023, GerritForge Ltd
+ *
+ * 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.util.concurrent.atomic.AtomicInteger;
+
+import org.eclipse.jgit.annotations.Nullable;
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.internal.JGitText;
+
+import java.io.IOException;
+import java.util.Comparator;
+import java.util.PriorityQueue;
+
+/**
+ * A queue of commits sorted by commit time order using a Java PriorityQueue.
+ * For the commits with the same commit time insertion order will be preserved.
+ */
+class DateRevPriorityQueue extends DateRevQueue {
+	private PriorityQueue<RevCommitEntry> queue;
+
+	private final AtomicInteger sequence = new AtomicInteger(1);
+
+	/**
+	 * Create an empty queue of commits sorted by commit time order.
+	 */
+	public DateRevPriorityQueue() {
+		this(false);
+	}
+
+	/**
+	 * Create an empty queue of commits sorted by commit time order.
+	 *
+	 * @param firstParent
+	 *            treat first element as a parent
+	 */
+	DateRevPriorityQueue(boolean firstParent) {
+		super(firstParent);
+		initPriorityQueue();
+	}
+
+	private void initPriorityQueue() {
+		sequence.set(1);
+		queue = new PriorityQueue<>(Comparator.comparingInt(
+						(RevCommitEntry ent) -> ent.getEntry().getCommitTime())
+				.reversed()
+				.thenComparingInt(RevCommitEntry::getInsertSequenceNumber));
+	}
+
+    DateRevPriorityQueue(Generator s) throws MissingObjectException,
+			IncorrectObjectTypeException, IOException {
+		this(s.firstParent);
+		for (;;) {
+			final RevCommit c = s.next();
+			if (c == null) {
+				break;
+			}
+			add(c);
+		}
+	}
+
+	@Override
+	public void add(RevCommit c) {
+		// PriorityQueue does not accept null values. To keep the same behaviour
+		// do the same check and throw the same exception before creating entry
+		if (c == null) {
+			throw new NullPointerException(JGitText.get().nullRevCommit);
+		}
+		queue.add(new RevCommitEntry(sequence.getAndIncrement(), c));
+	}
+
+	@Override
+	public RevCommit next() {
+		RevCommitEntry entry = queue.poll();
+		return entry == null ? null : entry.getEntry();
+	}
+
+	/**
+	 * Peek at the next commit, without removing it.
+	 *
+	 * @return the next available commit; null if there are no commits left.
+	 */
+	@Override
+	public @Nullable RevCommit peek() {
+		RevCommitEntry entry = queue.peek();
+		return entry == null ? null : entry.getEntry();
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public void clear() {
+		sequence.set(1);
+		queue.clear();
+	}
+
+	@Override
+	boolean everbodyHasFlag(int f) {
+		return queue.stream().map(RevCommitEntry::getEntry)
+				.noneMatch(c -> (c.flags & f) == 0);
+	}
+
+	@Override
+	boolean anybodyHasFlag(int f) {
+		return queue.stream().map(RevCommitEntry::getEntry)
+				.anyMatch(c -> (c.flags & f) != 0);
+	}
+
+	@Override
+	int outputType() {
+		return outputType | SORT_COMMIT_TIME_DESC;
+	}
+
+	@Override
+	public String toString() {
+		final StringBuilder s = new StringBuilder();
+		for (RevCommitEntry e : queue) {
+			describe(s, e.getEntry());
+		}
+		return s.toString();
+	}
+
+	private static class RevCommitEntry {
+		private final int insertSequenceNumber;
+
+		private final RevCommit entry;
+
+		public RevCommitEntry(int insertSequenceNumber, RevCommit entry) {
+			this.insertSequenceNumber = insertSequenceNumber;
+			this.entry = entry;
+		}
+
+		public int getInsertSequenceNumber() {
+			return insertSequenceNumber;
+		}
+
+		public RevCommit getEntry() {
+			return entry;
+		}
+	}
+}