pkg/pool: no need for double pointer for sync.Pool

Signed-off-by: Stephen J Day <stephen.day@docker.com>

pkg/pools/pools.go

@@ -19,30 +19,26 @@ import (
 
 var (
 	// BufioReader32KPool is a pool which returns bufio.Reader with a 32K buffer.
-	BufioReader32KPool *BufioReaderPool
+	BufioReader32KPool = newBufioReaderPoolWithSize(buffer32K)
 	// BufioWriter32KPool is a pool which returns bufio.Writer with a 32K buffer.
-	BufioWriter32KPool *BufioWriterPool
+	BufioWriter32KPool = newBufioWriterPoolWithSize(buffer32K)
 )
 
 const buffer32K = 32 * 1024
 
 // BufioReaderPool is a bufio reader that uses sync.Pool.
 type BufioReaderPool struct {
-	pool *sync.Pool
-}
-
-func init() {
-	BufioReader32KPool = newBufioReaderPoolWithSize(buffer32K)
-	BufioWriter32KPool = newBufioWriterPoolWithSize(buffer32K)
+	pool sync.Pool
 }
 
 // newBufioReaderPoolWithSize is unexported because new pools should be
 // added here to be shared where required.
 func newBufioReaderPoolWithSize(size int) *BufioReaderPool {
-	pool := &sync.Pool{
-		New: func() interface{} { return bufio.NewReaderSize(nil, size) },
+	return &BufioReaderPool{
+		pool: sync.Pool{
+			New: func() interface{} { return bufio.NewReaderSize(nil, size) },
+		},
 	}
-	return &BufioReaderPool{pool: pool}
 }
 
 // Get returns a bufio.Reader which reads from r. The buffer size is that of the pool.
@@ -80,16 +76,17 @@ func (bufPool *BufioReaderPool) NewReadCloserWrapper(buf *bufio.Reader, r io.Rea
 
 // BufioWriterPool is a bufio writer that uses sync.Pool.
 type BufioWriterPool struct {
-	pool *sync.Pool
+	pool sync.Pool
 }
 
 // newBufioWriterPoolWithSize is unexported because new pools should be
 // added here to be shared where required.
 func newBufioWriterPoolWithSize(size int) *BufioWriterPool {
-	pool := &sync.Pool{
-		New: func() interface{} { return bufio.NewWriterSize(nil, size) },
+	return &BufioWriterPool{
+		pool: sync.Pool{
+			New: func() interface{} { return bufio.NewWriterSize(nil, size) },
+		},
 	}
-	return &BufioWriterPool{pool: pool}
 }
 
 // Get returns a bufio.Writer which writes to w. The buffer size is that of the pool.