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fmt: use sync.Pool

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Update #4720

R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/43990043
This commit is contained in:
Brad Fitzpatrick 2013-12-18 11:09:07 -08:00
parent 8c6ef061e3
commit 0f9311811c
2 changed files with 10 additions and 39 deletions
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40
src/pkg/fmt/print.go
View File

@ -124,45 +124,13 @@ type pp struct {
fmt fmt
}
// A cache holds a set of reusable objects.
// The slice is a stack (LIFO).
// If more are needed, the cache creates them by calling new.
type cache struct {
mu sync.Mutex
saved []interface{}
new func() interface{}
var ppFree = sync.Pool{
New: func() interface{} { return new(pp) },
}
func (c *cache) put(x interface{}) {
c.mu.Lock()
if len(c.saved) < cap(c.saved) {
c.saved = append(c.saved, x)
}
c.mu.Unlock()
}
func (c *cache) get() interface{} {
c.mu.Lock()
n := len(c.saved)
if n == 0 {
c.mu.Unlock()
return c.new()
}
x := c.saved[n-1]
c.saved = c.saved[0 : n-1]
c.mu.Unlock()
return x
}
func newCache(f func() interface{}) *cache {
return &cache{saved: make([]interface{}, 0, 100), new: f}
}
var ppFree = newCache(func() interface{} { return new(pp) })
// newPrinter allocates a new pp struct or grab a cached one.
func newPrinter() *pp {
p := ppFree.get().(*pp)
p := ppFree.Get().(*pp)
p.panicking = false
p.erroring = false
p.fmt.init(&p.buf)
@ -178,7 +146,7 @@ func (p *pp) free() {
p.buf = p.buf[:0]
p.arg = nil
p.value = reflect.Value{}
ppFree.put(p)
ppFree.Put(p)
}
func (p *pp) Width() (wid int, ok bool) { return p.fmt.wid, p.fmt.widPresent }

9
src/pkg/fmt/scan.go
View File

@ -11,6 +11,7 @@ import (
"os"
"reflect"
"strconv"
"sync"
"unicode/utf8"
)
@ -380,7 +381,9 @@ func (r *readRune) ReadRune() (rr rune, size int, err error) {
return
}
var ssFree = newCache(func() interface{} { return new(ss) })
var ssFree = sync.Pool{
New: func() interface{} { return new(ss) },
}
// newScanState allocates a new ss struct or grab a cached one.
func newScanState(r io.Reader, nlIsSpace, nlIsEnd bool) (s *ss, old ssave) {
@ -395,7 +398,7 @@ func newScanState(r io.Reader, nlIsSpace, nlIsEnd bool) (s *ss, old ssave) {
return
}
s = ssFree.get().(*ss)
s = ssFree.Get().(*ss)
if rr, ok := r.(io.RuneReader); ok {
s.rr = rr
} else {
@ -427,7 +430,7 @@ func (s *ss) free(old ssave) {
}
s.buf = s.buf[:0]
s.rr = nil
ssFree.put(s)
ssFree.Put(s)
}
// skipSpace skips spaces and maybe newlines.