bug: add a Lamport logical clock to be able to sort bugs by creation time and edit time without having to rely on a timestamp

1 files changed, 57 insertions, 0 deletions

diff --git a/bug/sorting.go b/bug/sorting.go
new file mode 100644
index 00000000..231055bd
--- /dev/null
+++ b/bug/sorting.go
@@ -0,0 +1,57 @@
+package bug
+
+type BugsByCreationTime []*Bug
+
+func (b BugsByCreationTime) Len() int {
+	return len(b)
+}
+
+func (b BugsByCreationTime) Less(i, j int) bool {
+	if b[i].createTime < b[j].createTime {
+		return true
+	}
+
+	if b[i].createTime > b[j].createTime {
+		return false
+	}
+
+	// When the logical clocks are identical, that means we had a concurrent
+	// edition. In this case we rely on the timestamp. While the timestamp might
+	// be incorrect due to a badly set clock, the drift in sorting is bounded
+	// by the first sorting using the logical clock. That means that if user
+	// synchronize their bugs regularly, the timestamp will rarely be used, and
+	// should still provide a kinda accurate sorting when needed.
+	return b[i].firstOp().Time().Before(b[j].firstOp().Time())
+}
+
+func (b BugsByCreationTime) Swap(i, j int) {
+	b[i], b[j] = b[j], b[i]
+}
+
+type BugsByEditTime []*Bug
+
+func (b BugsByEditTime) Len() int {
+	return len(b)
+}
+
+func (b BugsByEditTime) Less(i, j int) bool {
+	if b[i].editTime < b[j].editTime {
+		return true
+	}
+
+	if b[i].editTime > b[j].editTime {
+		return false
+	}
+
+	// When the logical clocks are identical, that means we had a concurrent
+	// edition. In this case we rely on the timestamp. While the timestamp might
+	// be incorrect due to a badly set clock, the drift in sorting is bounded
+	// by the first sorting using the logical clock. That means that if user
+	// synchronize their bugs regularly, the timestamp will rarely be used, and
+	// should still provide a kinda accurate sorting when needed.
+	return b[i].lastOp().Time().Before(b[j].lastOp().Time())
+}
+
+func (b BugsByEditTime) Swap(i, j int) {
+	b[i], b[j] = b[j], b[i]
+}