sync: add Map.Clear

Fixes #61696

Change-Id: I0a31afd3bc433fc84280d56f2798bda10da61eba
GitHub-Last-Rev: 17bedc864f1685178a42b59f7083677a6124f831
GitHub-Pull-Request: golang/go#61702
Reviewed-on: https://go-review.googlesource.com/c/go/+/515015
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: qiulaidongfeng <2645477756@qq.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/src/sync/map_reference_test.go b/src/sync/map_reference_test.go
index aa5ebf352f..283da0f3a9 100644
--- a/src/sync/map_reference_test.go
+++ b/src/sync/map_reference_test.go
@@ -13,7 +13,7 @@ import (
 
 // mapInterface is the interface Map implements.
 type mapInterface interface {
-	Load(any) (any, bool)
+	Load(key any) (value any, ok bool)
 	Store(key, value any)
 	LoadOrStore(key, value any) (actual any, loaded bool)
 	LoadAndDelete(key any) (value any, loaded bool)
@@ -22,6 +22,7 @@ type mapInterface interface {
 	CompareAndSwap(key, old, new any) (swapped bool)
 	CompareAndDelete(key, old any) (deleted bool)
 	Range(func(key, value any) (shouldContinue bool))
+	Clear()
 }
 
 var (
@@ -144,6 +145,13 @@ func (m *RWMutexMap) Range(f func(key, value any) (shouldContinue bool)) {
 	}
 }
 
+func (m *RWMutexMap) Clear() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	clear(m.dirty)
+}
+
 // DeepCopyMap is an implementation of mapInterface using a Mutex and
 // atomic.Value.  It makes deep copies of the map on every write to avoid
 // acquiring the Mutex in Load.
@@ -269,3 +277,10 @@ func (m *DeepCopyMap) dirty() map[any]any {
 	}
 	return dirty
 }
+
+func (m *DeepCopyMap) Clear() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.clean.Store((map[any]any)(nil))
+}