From 14e5ea68ce7e08e3fc27ff237e66d41ed3e502ae Mon Sep 17 00:00:00 2001
From: Cristian Maglie <c.maglie@bug.st>
Date: Tue, 20 Feb 2024 15:24:08 +0100
Subject: [PATCH] Precompile port-filter regexp

---
 serial_darwin.go  | 9 +++++++--
 serial_freebsd.go | 9 +++++++--
 serial_linux.go   | 9 +++++++--
 serial_openbsd.go | 9 +++++++--
 serial_unix.go    | 7 +------
 5 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/serial_darwin.go b/serial_darwin.go
index 2817041..3baa489 100644
--- a/serial_darwin.go
+++ b/serial_darwin.go
@@ -6,10 +6,15 @@
 
 package serial
 
-import "golang.org/x/sys/unix"
+import (
+	"regexp"
+
+	"golang.org/x/sys/unix"
+)
 
 const devFolder = "/dev"
-const regexFilter = "^(cu|tty)\\..*"
+
+var osPortFiler = regexp.MustCompile("^(cu|tty)\\..*")
 
 const ioctlTcgetattr = unix.TIOCGETA
 const ioctlTcsetattr = unix.TIOCSETA
diff --git a/serial_freebsd.go b/serial_freebsd.go
index aceb08a..be0fa01 100644
--- a/serial_freebsd.go
+++ b/serial_freebsd.go
@@ -6,10 +6,15 @@
 
 package serial
 
-import "golang.org/x/sys/unix"
+import (
+	"regexp"
+
+	"golang.org/x/sys/unix"
+)
 
 const devFolder = "/dev"
-const regexFilter = "^(cu|tty)\\..*"
+
+var osPortFiler = regexp.MustCompile("^(cu|tty)\\..*")
 
 // termios manipulation functions
 
diff --git a/serial_linux.go b/serial_linux.go
index fe114d9..93482cd 100644
--- a/serial_linux.go
+++ b/serial_linux.go
@@ -6,10 +6,15 @@
 
 package serial
 
-import "golang.org/x/sys/unix"
+import (
+	"regexp"
+
+	"golang.org/x/sys/unix"
+)
 
 const devFolder = "/dev"
-const regexFilter = "(ttyS|ttyHS|ttyUSB|ttyACM|ttyAMA|rfcomm|ttyO|ttymxc)[0-9]{1,3}"
+
+var osPortFilter = regexp.MustCompile("(ttyS|ttyHS|ttyUSB|ttyACM|ttyAMA|rfcomm|ttyO|ttymxc)[0-9]{1,3}")
 
 // termios manipulation functions
 
diff --git a/serial_openbsd.go b/serial_openbsd.go
index 644dc92..e56a760 100644
--- a/serial_openbsd.go
+++ b/serial_openbsd.go
@@ -6,10 +6,15 @@
 
 package serial
 
-import "golang.org/x/sys/unix"
+import (
+	"regexp"
+
+	"golang.org/x/sys/unix"
+)
 
 const devFolder = "/dev"
-const regexFilter = "^(cu|tty)\\..*"
+
+var osPortFiler = regexp.MustCompile("^(cu|tty)\\..*")
 
 // termios manipulation functions
 
diff --git a/serial_unix.go b/serial_unix.go
index 9328656..dffdcb4 100644
--- a/serial_unix.go
+++ b/serial_unix.go
@@ -11,7 +11,6 @@ package serial
 import (
 	"fmt"
 	"os"
-	"regexp"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -298,10 +297,6 @@ func nativeGetPortsList() ([]string, error) {
 	}
 
 	ports := make([]string, 0, len(files))
-	regex, err := regexp.Compile(regexFilter)
-	if err != nil {
-		return nil, err
-	}
 	for _, f := range files {
 		// Skip folders
 		if f.IsDir() {
@@ -309,7 +304,7 @@ func nativeGetPortsList() ([]string, error) {
 		}
 
 		// Keep only devices with the correct name
-		if !regex.MatchString(f.Name()) {
+		if !osPortFilter.MatchString(f.Name()) {
 			continue
 		}