From 4dbce32738ac610f8cabc8db2133580f31dbadee Mon Sep 17 00:00:00 2001
From: Jakob Borg <jakob@nym.se>
Date: Wed, 18 Jun 2014 23:57:22 +0200
Subject: [PATCH] Simplify memory handling

---
 beacon/beacon.go     |  7 +++++--
 buffers/buffers.go   | 50 --------------------------------------------
 discover/discover.go |  6 +-----
 model/model.go       |  4 +---
 model/puller.go      |  6 +-----
 protocol/protocol.go |  1 -
 6 files changed, 8 insertions(+), 66 deletions(-)
 delete mode 100644 buffers/buffers.go

diff --git a/beacon/beacon.go b/beacon/beacon.go
index 8ad717611..f2bfd46a1 100644
--- a/beacon/beacon.go
+++ b/beacon/beacon.go
@@ -52,7 +52,7 @@ func (b *Beacon) Recv() ([]byte, net.Addr) {
 }
 
 func (b *Beacon) reader() {
-	var bs = make([]byte, 65536)
+	bs := make([]byte, 65536)
 	for {
 		n, addr, err := b.conn.ReadFrom(bs)
 		if err != nil {
@@ -62,8 +62,11 @@ func (b *Beacon) reader() {
 		if debug {
 			l.Debugf("recv %d bytes from %s", n, addr)
 		}
+
+		c := make([]byte, n)
+		copy(c, bs)
 		select {
-		case b.outbox <- recv{bs[:n], addr}:
+		case b.outbox <- recv{c, addr}:
 		default:
 			if debug {
 				l.Debugln("dropping message")
diff --git a/buffers/buffers.go b/buffers/buffers.go
deleted file mode 100644
index 51bedcdab..000000000
--- a/buffers/buffers.go
+++ /dev/null
@@ -1,50 +0,0 @@
-// Copyright (C) 2014 Jakob Borg and other contributors. All rights reserved.
-// Use of this source code is governed by an MIT-style license that can be
-// found in the LICENSE file.
-
-// Package buffers manages a set of reusable byte buffers.
-package buffers
-
-const (
-	largeMin = 1024
-)
-
-var (
-	smallBuffers = make(chan []byte, 32)
-	largeBuffers = make(chan []byte, 32)
-)
-
-func Get(size int) []byte {
-	var ch = largeBuffers
-	if size < largeMin {
-		ch = smallBuffers
-	}
-
-	var buf []byte
-	select {
-	case buf = <-ch:
-	default:
-	}
-
-	if len(buf) < size {
-		return make([]byte, size)
-	}
-	return buf[:size]
-}
-
-func Put(buf []byte) {
-	buf = buf[:cap(buf)]
-	if len(buf) == 0 {
-		return
-	}
-
-	var ch = largeBuffers
-	if len(buf) < largeMin {
-		ch = smallBuffers
-	}
-
-	select {
-	case ch <- buf:
-	default:
-	}
-}
diff --git a/discover/discover.go b/discover/discover.go
index decebe839..4eb82d388 100644
--- a/discover/discover.go
+++ b/discover/discover.go
@@ -14,7 +14,6 @@ import (
 	"time"
 
 	"github.com/calmh/syncthing/beacon"
-	"github.com/calmh/syncthing/buffers"
 )
 
 type Discoverer struct {
@@ -329,11 +328,8 @@ func (d *Discoverer) externalLookup(node string) []string {
 		}
 		return nil
 	}
-	buffers.Put(buf)
-
-	buf = buffers.Get(2048)
-	defer buffers.Put(buf)
 
+	buf = make([]byte, 2048)
 	n, err := conn.Read(buf)
 	if err != nil {
 		if err, ok := err.(net.Error); ok && err.Timeout() {
diff --git a/model/model.go b/model/model.go
index 08284baf3..9f581e23a 100644
--- a/model/model.go
+++ b/model/model.go
@@ -15,8 +15,6 @@ import (
 	"path/filepath"
 	"sync"
 	"time"
-
-	"github.com/calmh/syncthing/buffers"
 	"github.com/calmh/syncthing/cid"
 	"github.com/calmh/syncthing/config"
 	"github.com/calmh/syncthing/files"
@@ -433,7 +431,7 @@ func (m *Model) Request(nodeID, repo, name string, offset int64, size int) ([]by
 	}
 	defer fd.Close()
 
-	buf := buffers.Get(int(size))
+	buf := make([]byte, size)
 	_, err = fd.ReadAt(buf, offset)
 	if err != nil {
 		return nil, err
diff --git a/model/puller.go b/model/puller.go
index e13778f0f..77eba070a 100644
--- a/model/puller.go
+++ b/model/puller.go
@@ -11,8 +11,6 @@ import (
 	"path/filepath"
 	"runtime"
 	"time"
-
-	"github.com/calmh/syncthing/buffers"
 	"github.com/calmh/syncthing/cid"
 	"github.com/calmh/syncthing/config"
 	"github.com/calmh/syncthing/osutil"
@@ -339,7 +337,6 @@ func (p *puller) handleRequestResult(res requestResult) {
 	}
 
 	_, of.err = of.file.WriteAt(res.data, res.offset)
-	buffers.Put(res.data)
 
 	of.outstanding--
 	p.openFiles[f.Name] = of
@@ -490,12 +487,11 @@ func (p *puller) handleCopyBlock(b bqBlock) {
 	defer exfd.Close()
 
 	for _, b := range b.copy {
-		bs := buffers.Get(int(b.Size))
+		bs := make([]byte, b.Size)
 		_, of.err = exfd.ReadAt(bs, b.Offset)
 		if of.err == nil {
 			_, of.err = of.file.WriteAt(bs, b.Offset)
 		}
-		buffers.Put(bs)
 		if of.err != nil {
 			if debug {
 				l.Debugf("pull: error: %q / %q: %v", p.repoCfg.ID, f.Name, of.err)
diff --git a/protocol/protocol.go b/protocol/protocol.go
index 56f1338a5..75c304d08 100644
--- a/protocol/protocol.go
+++ b/protocol/protocol.go
@@ -12,7 +12,6 @@ import (
 	"io"
 	"sync"
 	"time"
-
 	"github.com/calmh/syncthing/xdr"
 )