Update vendor (#1265)

vendor/github.com/mattermost/logr/levelcache.go

@@ -0,0 +1,98 @@
+package logr
+
+import (
+	"fmt"
+	"sync"
+)
+
+// LevelStatus represents whether a level is enabled and
+// requires a stack trace.
+type LevelStatus struct {
+	Enabled    bool
+	Stacktrace bool
+	empty      bool
+}
+
+type levelCache interface {
+	setup()
+	get(id LevelID) (LevelStatus, bool)
+	put(id LevelID, status LevelStatus) error
+	clear()
+}
+
+// syncMapLevelCache uses sync.Map which may better handle large concurrency
+// scenarios.
+type syncMapLevelCache struct {
+	m sync.Map
+}
+
+func (c *syncMapLevelCache) setup() {
+	c.clear()
+}
+
+func (c *syncMapLevelCache) get(id LevelID) (LevelStatus, bool) {
+	if id > MaxLevelID {
+		return LevelStatus{}, false
+	}
+	s, _ := c.m.Load(id)
+	status := s.(LevelStatus)
+	return status, !status.empty
+}
+
+func (c *syncMapLevelCache) put(id LevelID, status LevelStatus) error {
+	if id > MaxLevelID {
+		return fmt.Errorf("level id cannot exceed MaxLevelID (%d)", MaxLevelID)
+	}
+	c.m.Store(id, status)
+	return nil
+}
+
+func (c *syncMapLevelCache) clear() {
+	var i LevelID
+	for i = 0; i < MaxLevelID; i++ {
+		c.m.Store(i, LevelStatus{empty: true})
+	}
+}
+
+// arrayLevelCache using array and a mutex.
+type arrayLevelCache struct {
+	arr [MaxLevelID + 1]LevelStatus
+	mux sync.RWMutex
+}
+
+func (c *arrayLevelCache) setup() {
+	c.clear()
+}
+
+//var dummy = LevelStatus{}
+
+func (c *arrayLevelCache) get(id LevelID) (LevelStatus, bool) {
+	if id > MaxLevelID {
+		return LevelStatus{}, false
+	}
+	c.mux.RLock()
+	status := c.arr[id]
+	ok := !status.empty
+	c.mux.RUnlock()
+	return status, ok
+}
+
+func (c *arrayLevelCache) put(id LevelID, status LevelStatus) error {
+	if id > MaxLevelID {
+		return fmt.Errorf("level id cannot exceed MaxLevelID (%d)", MaxLevelID)
+	}
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	c.arr[id] = status
+	return nil
+}
+
+func (c *arrayLevelCache) clear() {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	for i := range c.arr {
+		c.arr[i] = LevelStatus{empty: true}
+	}
+}