Thread-safe impl for CacheRegion

maker/golang/xdb/editor.go

@@ -108,7 +108,7 @@ func (e *Editor) loadSegments() error {
 				e.segments.PushBack(&Segment{
 					StartIP: e.verison.Min,
 					EndIP:   IPSubOne(seg.StartIP),
-					Region:  REmpty(),
+					Region:  EmptyRegion,
 				})
 			}
 		} else if err := seg.RightBehind(last); err == nil {
@@ -121,7 +121,7 @@ func (e *Editor) loadSegments() error {
 			e.segments.PushBack(&Segment{
 				StartIP: IPAddOne(last.EndIP),
 				EndIP:   IPSubOne(seg.StartIP),
-				Region:  REmpty(),
+				Region:  EmptyRegion,
 			})
 		}
 
@@ -138,7 +138,7 @@ func (e *Editor) loadSegments() error {
 			e.segments.PushBack(&Segment{
 				StartIP: IPAddOne(back.Value.(*Segment).EndIP),
 				EndIP:   e.verison.Max,
-				Region:  REmpty(),
+				Region:  EmptyRegion,
 			})
 		}
 	}

maker/golang/xdb/region.go

@@ -3,31 +3,32 @@ package xdb
 import (
 	"fmt"
 	"strings"
+	"sync"
 )
 
 // region manager with:
 // 1, content cache.
 // 2, util functions
 
+// global cache map
+var rcLock sync.Mutex
+var regionCache = map[string]*Region{}
+
 type Region struct {
 	Str    string   // region string
 	fields []string // region fields
 }
 
-// global cache map
-var regionCache = map[string]*Region{}
+var EmptyRegion = CacheRegion("")
 
-func RNew(str string) *Region {
-	return NewRegion(str)
-}
-
-func REmpty() *Region {
-	return NewRegion("")
-}
-
-func NewRegion(str string) *Region {
+// Create or get the region from the global cache.
+// And it is a thread-safe implementation.
+func CacheRegion(str string) *Region {
 	// check the cache and return it directly
 	// if there is a cache available
+	rcLock.Lock()
+	defer rcLock.Unlock()
+
 	region, ok := regionCache[str]
 	if ok {
 		return region
@@ -43,6 +44,14 @@ func NewRegion(str string) *Region {
 	return region
 }
 
+// Create a new region without checking cache info
+func NewRegion(str string) *Region {
+	return &Region{
+		Str:    str,
+		fields: nil,
+	}
+}
+
 func (r *Region) Fields() []string {
 	if r.fields == nil {
 		r.fields = strings.Split(r.Str, "|")
@@ -51,7 +60,7 @@ func (r *Region) Fields() []string {
 	return r.fields
 }
 
-func (r *Region) JoinBy(sep string) string {
+func (r *Region) Join(sep string) string {
 	if sep == "|" {
 		return r.Str
 	}
@@ -78,7 +87,7 @@ func (r *Region) Filtering(fields []int) (*Region, error) {
 		sb = append(sb, fs[idx])
 	}
 
-	new := RNew(strings.Join(sb, "|"))
+	new := CacheRegion(strings.Join(sb, "|"))
 	if new.fields == nil {
 		new.fields = sb
 	}

maker/golang/xdb/segment.go

@@ -38,7 +38,7 @@ func SegmentFrom(seg string) (*Segment, error) {
 	return &Segment{
 		StartIP: sip,
 		EndIP:   eip,
-		Region:  RNew(ps[2]),
+		Region:  CacheRegion(ps[2]),
 	}, nil
 }
 

maker/golang/xdb/util.go

@@ -200,7 +200,7 @@ func IterateSegments(handle *os.File, autoMerge bool, before func(l string), fil
 		var seg = &Segment{
 			StartIP: sip,
 			EndIP:   eip,
-			Region:  RNew(region),
+			Region:  CacheRegion(region),
 		}
 
 		// check and automatic merging the Consecutive Segments, which means: