From 1771cec23d036987d9b384c891e40a0cf901014b Mon Sep 17 00:00:00 2001
From: qsyqian <qsyqian@gmail.com>
Date: Wed, 19 Oct 2022 18:26:41 +0800
Subject: [PATCH] lessor: refactor expireExists to make it more clear

Signed-off-by: qsyqian <qsyqian@gmail.com>
---
 server/lease/lease_queue_test.go | 12 ++++++------
 server/lease/lessor.go           | 19 ++++++++-----------
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/server/lease/lease_queue_test.go b/server/lease/lease_queue_test.go
index 9b9bb772f..a25af1a4f 100644
--- a/server/lease/lease_queue_test.go
+++ b/server/lease/lease_queue_test.go
@@ -45,13 +45,13 @@ func TestLeaseQueue(t *testing.T) {
 	}
 
 	existExpiredEvent := func() {
-		l, ok, more := le.expireExists()
+		l, more := le.expireExists()
+		if l == nil {
+			t.Fatalf("expect expiry lease exists")
+		}
 		if l.ID != 1 {
 			t.Fatalf("first item expected lease ID %d, got %d", 1, l.ID)
 		}
-		if !ok {
-			t.Fatal("expect expiry lease exists")
-		}
 		if more {
 			t.Fatal("expect no more expiry lease")
 		}
@@ -67,8 +67,8 @@ func TestLeaseQueue(t *testing.T) {
 
 	noExpiredEvent := func() {
 		// re-acquire the expired item, nothing exists
-		_, ok, more := le.expireExists()
-		if ok {
+		l, more := le.expireExists()
+		if l != nil {
 			t.Fatal("expect no expiry lease exists")
 		}
 		if more {
diff --git a/server/lease/lessor.go b/server/lease/lessor.go
index 613bee215..0dd8f9e6d 100644
--- a/server/lease/lessor.go
+++ b/server/lease/lessor.go
@@ -675,12 +675,12 @@ func (le *lessor) clearLeaseExpiredNotifier() {
 	le.leaseExpiredNotifier = newLeaseExpiredNotifier()
 }
 
-// expireExists returns true if expiry items exist.
+// expireExists returns "l" which is not nil if expiry items exist.
 // It pops only when expiry item exists.
 // "next" is true, to indicate that it may exist in next attempt.
-func (le *lessor) expireExists() (l *Lease, ok bool, next bool) {
+func (le *lessor) expireExists() (l *Lease, next bool) {
 	if le.leaseExpiredNotifier.Len() == 0 {
-		return nil, false, false
+		return nil, false
 	}
 
 	item := le.leaseExpiredNotifier.Peek()
@@ -689,19 +689,19 @@ func (le *lessor) expireExists() (l *Lease, ok bool, next bool) {
 		// lease has expired or been revoked
 		// no need to revoke (nothing is expiry)
 		le.leaseExpiredNotifier.Unregister() // O(log N)
-		return nil, false, true
+		return nil, true
 	}
 	now := time.Now()
 	if now.Before(item.time) /* item.time: expiration time */ {
 		// Candidate expirations are caught up, reinsert this item
 		// and no need to revoke (nothing is expiry)
-		return l, false, false
+		return nil, false
 	}
 
 	// recheck if revoke is complete after retry interval
 	item.time = now.Add(le.expiredLeaseRetryInterval)
 	le.leaseExpiredNotifier.RegisterOrUpdate(item)
-	return l, true, false
+	return l, false
 }
 
 // findExpiredLeases loops leases in the leaseMap until reaching expired limit
@@ -710,13 +710,10 @@ func (le *lessor) findExpiredLeases(limit int) []*Lease {
 	leases := make([]*Lease, 0, 16)
 
 	for {
-		l, ok, next := le.expireExists()
-		if !ok && !next {
+		l, next := le.expireExists()
+		if l == nil && !next {
 			break
 		}
-		if !ok {
-			continue
-		}
 		if next {
 			continue
 		}