expvar: add Value methods

Closes #15815

Change-Id: I08154dbff416198cf7787e446b1e00e62c03a972
Reviewed-on: https://go-review.googlesource.com/30917
Reviewed-by: Brad Fitzpatrick <[email protected]>
Run-TryBot: Brad Fitzpatrick <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>

Author: FiloSottile

src/expvar/expvar.go

@@ -49,6 +49,10 @@ type Int struct {
 	i int64
 }
 
+func (v *Int) Value() int64 {
+	return atomic.LoadInt64(&v.i)
+}
+
 func (v *Int) String() string {
 	return strconv.FormatInt(atomic.LoadInt64(&v.i), 10)
 }
@@ -66,6 +70,10 @@ type Float struct {
 	f uint64
 }
 
+func (v *Float) Value() float64 {
+	return math.Float64frombits(atomic.LoadUint64(&v.f))
+}
+
 func (v *Float) String() string {
 	return strconv.FormatFloat(
 		math.Float64frombits(atomic.LoadUint64(&v.f)), 'g', -1, 64)
@@ -219,6 +227,14 @@ type String struct {
 	s  string
 }
 
+func (v *String) Value() string {
+	v.mu.RLock()
+	defer v.mu.RUnlock()
+	return v.s
+}
+
+// String implements the Val interface. To get the unquoted string
+// use Value.
 func (v *String) String() string {
 	v.mu.RLock()
 	s := v.s
@@ -237,6 +253,10 @@ func (v *String) Set(value string) {
 // and formatting the returned value using JSON.
 type Func func() interface{}
 
+func (f Func) Value() interface{} {
+	return f()
+}
+
 func (f Func) String() string {
 	v, _ := json.Marshal(f())
 	return string(v)

src/expvar/expvar_test.go

@@ -7,13 +7,12 @@ package expvar
 import (
 	"bytes"
 	"encoding/json"
-	"math"
 	"net"
 	"net/http/httptest"
+	"reflect"
 	"runtime"
 	"strconv"
 	"sync"
-	"sync/atomic"
 	"testing"
 )
 
@@ -58,6 +57,10 @@ func TestInt(t *testing.T) {
 	if reqs.i != -2 {
 		t.Errorf("reqs.i = %v, want -2", reqs.i)
 	}
+
+	if v, want := reqs.Value(), int64(-2); v != want {
+		t.Errorf("reqs.Value() = %q, want %q", v, want)
+	}
 }
 
 func BenchmarkIntAdd(b *testing.B) {
@@ -80,10 +83,6 @@ func BenchmarkIntSet(b *testing.B) {
 	})
 }
 
-func (v *Float) val() float64 {
-	return math.Float64frombits(atomic.LoadUint64(&v.f))
-}
-
 func TestFloat(t *testing.T) {
 	RemoveAll()
 	reqs := NewFloat("requests-float")
@@ -96,17 +95,17 @@ func TestFloat(t *testing.T) {
 
 	reqs.Add(1.5)
 	reqs.Add(1.25)
-	if v := reqs.val(); v != 2.75 {
-		t.Errorf("reqs.val() = %v, want 2.75", v)
+	if v := reqs.Value(); v != 2.75 {
+		t.Errorf("reqs.Value() = %v, want 2.75", v)
 	}
 
 	if s := reqs.String(); s != "2.75" {
 		t.Errorf("reqs.String() = %q, want \"4.64\"", s)
 	}
 
 	reqs.Add(-2)
-	if v := reqs.val(); v != 0.75 {
-		t.Errorf("reqs.val() = %v, want 0.75", v)
+	if v := reqs.Value(); v != 0.75 {
+		t.Errorf("reqs.Value() = %v, want 0.75", v)
 	}
 }
 
@@ -146,6 +145,10 @@ func TestString(t *testing.T) {
 		t.Errorf("from %q, name.String() = %q, want %q", name.s, s, want)
 	}
 
+	if s, want := name.Value(), "Mike"; s != want {
+		t.Errorf("from %q, name.Value() = %q, want %q", name.s, s, want)
+	}
+
 	// Make sure we produce safe JSON output.
 	name.Set(`<`)
 	if s, want := name.String(), "\"\\u003c\""; s != want {
@@ -177,7 +180,7 @@ func TestMapCounter(t *testing.T) {
 	if x := colors.m["blue"].(*Int).i; x != 4 {
 		t.Errorf("colors.m[\"blue\"] = %v, want 4", x)
 	}
-	if x := colors.m[`green "midori"`].(*Float).val(); x != 4.125 {
+	if x := colors.m[`green "midori"`].(*Float).Value(); x != 4.125 {
 		t.Errorf("colors.m[`green \"midori\"] = %v, want 4.125", x)
 	}
 
@@ -242,6 +245,9 @@ func TestFunc(t *testing.T) {
 	if s, exp := f.String(), `["a","b"]`; s != exp {
 		t.Errorf(`f.String() = %q, want %q`, s, exp)
 	}
+	if v := f.Value(); !reflect.DeepEqual(v, x) {
+		t.Errorf(`f.Value() = %q, want %q`, v, x)
+	}
 
 	x = 17
 	if s, exp := f.String(), `17`; s != exp {