text/template/parse: use strings.Builder in Chain and List nodes

This CL is a continuation of 198078. Benchmark output:

benchmark                     old ns/op     new ns/op     delta
BenchmarkParseLarge-8         24759165      24516563      -0.98%
BenchmarkVariableString-8     115           115           +0.00%
BenchmarkListString-8         924           680           -26.41%

benchmark                     old allocs     new allocs     delta
BenchmarkVariableString-8     3              3              +0.00%
BenchmarkListString-8         14             13             -7.14%

benchmark                     old bytes     new bytes     delta
BenchmarkVariableString-8     72            72            +0.00%
BenchmarkListString-8         512           424           -17.19%

Change-Id: I9ec48fe4832437c556a5fa94d4cbf6e29e28d944
Reviewed-on: https://go-review.googlesource.com/c/go/+/198080
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/text/template/parse/node.go b/src/text/template/parse/node.go
index 2eb1af0a952a741c9eb9151064b53b44c772c376..61c6853679a5b7dcba657e45c6aa6512e18aa959 100644 (file)
--- a/src/text/template/parse/node.go
+++ b/src/text/template/parse/node.go
@@ -7,7 +7,6 @@
 package parse
 
 import (
-       "bytes"
        "fmt"
        "strconv"
        "strings"
@@ -94,11 +93,11 @@ func (l *ListNode) tree() *Tree {
 }
 
 func (l *ListNode) String() string {
-       b := new(bytes.Buffer)
+       var sb strings.Builder
        for _, n := range l.Nodes {
-               fmt.Fprint(b, n)
+               sb.WriteString(n.String())
        }
-       return b.String()
+       return sb.String()
 }
 
 func (l *ListNode) CopyList() *ListNode {
@@ -472,14 +471,19 @@ func (c *ChainNode) Add(field string) {
 }
 
 func (c *ChainNode) String() string {
-       s := c.Node.String()
+       var sb strings.Builder
        if _, ok := c.Node.(*PipeNode); ok {
-               s = "(" + s + ")"
+               sb.WriteByte('(')
+               sb.WriteString(c.Node.String())
+               sb.WriteByte(')')
+       } else {
+               sb.WriteString(c.Node.String())
        }
        for _, field := range c.Field {
-               s += "." + field
+               sb.WriteByte('.')
+               sb.WriteString(field)
        }
-       return s
+       return sb.String()
 }
 
 func (c *ChainNode) tree() *Tree {

diff --git a/src/text/template/parse/parse_test.go b/src/text/template/parse/parse_test.go
index 371de5d67ccd5a9204a6ebae2e8a966c6560f35d..86a100bb5f83210dae4f4851465edafa80b5b88a 100644 (file)
--- a/src/text/template/parse/parse_test.go
+++ b/src/text/template/parse/parse_test.go
@@ -554,7 +554,7 @@ func BenchmarkParseLarge(b *testing.B) {
        }
 }
 
-var sink string
+var sinkv, sinkl string
 
 func BenchmarkVariableString(b *testing.B) {
        v := &VariableNode{
@@ -563,9 +563,25 @@ func BenchmarkVariableString(b *testing.B) {
        b.ResetTimer()
        b.ReportAllocs()
        for i := 0; i < b.N; i++ {
-               sink = v.String()
+               sinkv = v.String()
        }
-       if sink == "" {
+       if sinkv == "" {
+               b.Fatal("Benchmark was not run")
+       }
+}
+
+func BenchmarkListString(b *testing.B) {
+       text := `{{ (printf .Field1.Field2.Field3).Value }}`
+       tree, err := New("bench").Parse(text, "", "", make(map[string]*Tree), builtins)
+       if err != nil {
+               b.Fatal(err)
+       }
+       b.ResetTimer()
+       b.ReportAllocs()
+       for i := 0; i < b.N; i++ {
+               sinkl = tree.Root.String()
+       }
+       if sinkl == "" {
                b.Fatal("Benchmark was not run")
        }
 }