From ac400acfd0ed25169a0a9c80cbc611a73dffdad2 Mon Sep 17 00:00:00 2001
From: sinkingpoint <colin@quirl.co.nz>
Date: Thu, 11 Jul 2024 11:20:06 +1200
Subject: [PATCH] Re-use Syslog Readers

Signed-off-by: sinkingpoint <colin@quirl.co.nz>
---
 octetcounting/parser.go  |  4 ++--
 octetcounting/scanner.go | 36 +++++++++++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/octetcounting/parser.go b/octetcounting/parser.go
index 5a5d4f8..a8d63cc 100644
--- a/octetcounting/parser.go
+++ b/octetcounting/parser.go
@@ -5,15 +5,14 @@ import (
 	"io"
 
 	syslog "github.com/leodido/go-syslog/v4"
-	"github.com/leodido/go-syslog/v4/rfc5424"
 	"github.com/leodido/go-syslog/v4/rfc3164"
+	"github.com/leodido/go-syslog/v4/rfc5424"
 )
 
 // parser is capable to parse the input stream containing syslog messages with octetcounting framing.
 //
 // Use NewParser function to instantiate one.
 type parser struct {
-	msglen           int64
 	maxMessageLength int
 	s                Scanner
 	internal         syslog.Machine
@@ -96,6 +95,7 @@ func (p *parser) Parse(r io.Reader) {
 }
 
 func (p *parser) run() {
+	defer p.s.Release()
 	for {
 		var tok Token
 
diff --git a/octetcounting/scanner.go b/octetcounting/scanner.go
index 7926515..6317db0 100644
--- a/octetcounting/scanner.go
+++ b/octetcounting/scanner.go
@@ -5,8 +5,38 @@ import (
 	"bytes"
 	"io"
 	"strconv"
+	"sync"
 )
 
+var readerPool sync.Pool
+
+// getReader returns a *bufio.Reader that is guaranteed
+// to have a buffer of at least `size`.
+func getReader(r io.Reader, size int) *bufio.Reader {
+	if buf := readerPool.Get(); buf != nil {
+		buf := buf.(*bufio.Reader)
+
+		// If the buffer we get is smaller than the requested buffer, put it back
+		// and create a new one. stdlib has multiple buckets for various sizes to
+		// make this more efficient, but that's overkill here.
+		if buf.Size() < size {
+			readerPool.Put(buf)
+			buf = bufio.NewReaderSize(r, size)
+		} else {
+			buf.Reset(r)
+		}
+
+		return buf
+	}
+
+	return bufio.NewReaderSize(r, size)
+}
+
+// putReader returns the given bufio.Reader to the pool to be used again.
+func putReader(r *bufio.Reader) {
+	readerPool.Put(r)
+}
+
 // eof represents a marker byte for the end of the reader
 var eof = byte(0)
 
@@ -39,7 +69,7 @@ type Scanner struct {
 // NewScanner returns a pointer to a new instance of Scanner.
 func NewScanner(r io.Reader, maxLength int) *Scanner {
 	return &Scanner{
-		r: bufio.NewReaderSize(r, maxLength+20), // max uint64 is 19 characters + a space
+		r: getReader(r, maxLength+20), // max uint64 is 19 characters + a space
 	}
 }
 
@@ -151,3 +181,7 @@ func (s *Scanner) scanSyslogMsg() Token {
 		lit: b,
 	}
 }
+
+func (s *Scanner) Release() {
+	putReader(s.r)
+}