From 52fd0e53caf3bba4f2dd5c69880f8bb6caecd03a Mon Sep 17 00:00:00 2001
From: Carlo Alberto Ferraris <cafxx@strayorange.com>
Date: Fri, 28 Feb 2020 19:04:54 +0900
Subject: [PATCH] Make Buffer.EnsureSpace inlineable

Split the slow path into a separate function, so that the fast path in EnsureSpace becomes inlineable.

This allows code in jwriter to inline the fast path.
---
 buffer/pool.go | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/buffer/pool.go b/buffer/pool.go
index 07fb4bc..4c508f7 100644
--- a/buffer/pool.go
+++ b/buffer/pool.go
@@ -78,9 +78,12 @@ type Buffer struct {
 // EnsureSpace makes sure that the current chunk contains at least s free bytes,
 // possibly creating a new chunk.
 func (b *Buffer) EnsureSpace(s int) {
-	if cap(b.Buf)-len(b.Buf) >= s {
-		return
+	if cap(b.Buf)-len(b.Buf) < s {
+		b.ensureSpaceSlow(s)
 	}
+}
+
+func (b *Buffer) ensureSpaceSlow(s int) {
 	l := len(b.Buf)
 	if l > 0 {
 		if cap(b.toPool) != cap(b.Buf) {
@@ -105,18 +108,14 @@ func (b *Buffer) EnsureSpace(s int) {
 
 // AppendByte appends a single byte to buffer.
 func (b *Buffer) AppendByte(data byte) {
-	if cap(b.Buf) == len(b.Buf) { // EnsureSpace won't be inlined.
-		b.EnsureSpace(1)
-	}
+	b.EnsureSpace(1)
 	b.Buf = append(b.Buf, data)
 }
 
 // AppendBytes appends a byte slice to buffer.
 func (b *Buffer) AppendBytes(data []byte) {
 	for len(data) > 0 {
-		if cap(b.Buf) == len(b.Buf) { // EnsureSpace won't be inlined.
-			b.EnsureSpace(1)
-		}
+		b.EnsureSpace(1)
 
 		sz := cap(b.Buf) - len(b.Buf)
 		if sz > len(data) {
@@ -131,9 +130,7 @@ func (b *Buffer) AppendBytes(data []byte) {
 // AppendBytes appends a string to buffer.
 func (b *Buffer) AppendString(data string) {
 	for len(data) > 0 {
-		if cap(b.Buf) == len(b.Buf) { // EnsureSpace won't be inlined.
-			b.EnsureSpace(1)
-		}
+		b.EnsureSpace(1)
 
 		sz := cap(b.Buf) - len(b.Buf)
 		if sz > len(data) {