| /* |
| * Copyright (C) 2019, Thomas Wolf <thomas.wolf@paranor.ch> 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.treewalk; |
| |
| import java.time.Instant; |
| import java.util.Comparator; |
| |
| /** |
| * Specialized comparator for {@link Instant}s. If either timestamp has a zero |
| * fraction, compares only seconds. If either timestamp has no time fraction |
| * smaller than a millisecond, compares only milliseconds. If either timestamp |
| * has no fraction smaller than a microsecond, compares only microseconds. |
| */ |
| class InstantComparator implements Comparator<Instant> { |
| |
| @Override |
| public int compare(Instant a, Instant b) { |
| return compare(a, b, false); |
| } |
| |
| /** |
| * Compares two {@link Instant}s to the lower resolution of the two |
| * instants. See {@link InstantComparator}. |
| * |
| * @param a |
| * first {@link Instant} to compare |
| * @param b |
| * second {@link Instant} to compare |
| * @param forceSecondsOnly |
| * whether to omit all fraction comparison |
| * @return a value < 0 if a < b, a value > 0 if a > b, and 0 if |
| * a == b |
| */ |
| public int compare(Instant a, Instant b, boolean forceSecondsOnly) { |
| long aSeconds = a.getEpochSecond(); |
| long bSeconds = b.getEpochSecond(); |
| int result = Long.compare(aSeconds, bSeconds); |
| if (result != 0) { |
| return result; |
| } |
| int aSubSecond = a.getNano(); |
| int bSubSecond = b.getNano(); |
| if (forceSecondsOnly || (aSubSecond == 0) |
| || (bSubSecond == 0)) { |
| // Don't check the subseconds part. |
| return 0; |
| } else if (aSubSecond != bSubSecond) { |
| // If either has nothing smaller than a millisecond, compare only |
| // milliseconds. |
| int aSubMillis = aSubSecond % 1_000_000; |
| int bSubMillis = bSubSecond % 1_000_000; |
| if (aSubMillis == 0) { |
| bSubSecond -= bSubMillis; |
| } else if (bSubMillis == 0) { |
| aSubSecond -= aSubMillis; |
| } else { |
| // Same again, but for microsecond resolution. NTFS has 100ns |
| // resolution, but WindowsFileAttributes may provide only |
| // microseconds (1000ns). Similar for some Unix file systems. |
| int aSubMicros = aSubSecond % 1000; |
| int bSubMicros = bSubSecond % 1000; |
| if (aSubMicros == 0) { |
| bSubSecond -= bSubMicros; |
| } else if (bSubMicros == 0) { |
| aSubSecond -= aSubMicros; |
| } |
| } |
| } |
| return Integer.compare(aSubSecond, bSubSecond); |
| } |
| |
| } |