expvar: add missing locking in String methods

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5726062

diff --git a/src/pkg/expvar/expvar.go b/src/pkg/expvar/expvar.go
index 1919296ea8f6495f0d72f7671dabc100509dce86..af5ce61aba632c7bcf6f0f5cfc4fde412070f8b8 100644 (file)
--- a/src/pkg/expvar/expvar.go
+++ b/src/pkg/expvar/expvar.go
@@ -44,7 +44,11 @@ type Int struct {
        mu sync.Mutex
 }
 
-func (v *Int) String() string { return strconv.FormatInt(v.i, 10) }
+func (v *Int) String() string {
+       v.mu.Lock()
+       defer v.mu.Unlock()
+       return strconv.FormatInt(v.i, 10)
+}
 
 func (v *Int) Add(delta int64) {
        v.mu.Lock()
@@ -64,7 +68,11 @@ type Float struct {
        mu sync.Mutex
 }
 
-func (v *Float) String() string { return strconv.FormatFloat(v.f, 'g', -1, 64) }
+func (v *Float) String() string {
+       v.mu.Lock()
+       defer v.mu.Unlock()
+       return strconv.FormatFloat(v.f, 'g', -1, 64)
+}
 
 // Add adds delta to v.
 func (v *Float) Add(delta float64) {
@@ -95,17 +103,17 @@ type KeyValue struct {
 func (v *Map) String() string {
        v.mu.RLock()
        defer v.mu.RUnlock()
-       b := new(bytes.Buffer)
-       fmt.Fprintf(b, "{")
+       var b bytes.Buffer
+       fmt.Fprintf(&b, "{")
        first := true
        for key, val := range v.m {
                if !first {
-                       fmt.Fprintf(b, ", ")
+                       fmt.Fprintf(&b, ", ")
                }
-               fmt.Fprintf(b, "\"%s\": %v", key, val)
+               fmt.Fprintf(&b, "\"%s\": %v", key, val)
                first = false
        }
-       fmt.Fprintf(b, "}")
+       fmt.Fprintf(&b, "}")
        return b.String()
 }