From 91c331e476b5090d4dd4fb85b82f45c890d39e46 Mon Sep 17 00:00:00 2001
From: hossinasaadi <hossin.asaadi@gmail.com>
Date: Tue, 30 Dec 2025 17:50:54 +0330
Subject: [PATCH 1/2] Implement mmap in filesystem to reduce ram usage

---
 common/platform/filesystem/file.go | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/common/platform/filesystem/file.go b/common/platform/filesystem/file.go
index e4fe2a9aaea1..f7f434ded3f4 100644
--- a/common/platform/filesystem/file.go
+++ b/common/platform/filesystem/file.go
@@ -4,6 +4,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"syscall"
 
 	"github.com/xtls/xray-core/common/buf"
 	"github.com/xtls/xray-core/common/platform"
@@ -16,6 +17,29 @@ var NewFileReader FileReaderFunc = func(path string) (io.ReadCloser, error) {
 }
 
 func ReadFile(path string) ([]byte, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	stat, err := file.Stat()
+	if err != nil {
+		return nil, err
+	}
+
+	size := stat.Size()
+	if size == 0 {
+		return []byte{}, nil
+	}
+
+	// use mmap to save RAM
+	bs, err := syscall.Mmap(int(file.Fd()), 0, int(size), syscall.PROT_READ, syscall.MAP_SHARED)
+	if err == nil {
+		return bs, nil
+	}
+
+	// fallback
 	reader, err := NewFileReader(path)
 	if err != nil {
 		return nil, err

From d66d752146e5b1f79819b9590201e1687a4daa74 Mon Sep 17 00:00:00 2001
From: hossinasaadi <hossin.asaadi@gmail.com>
Date: Tue, 30 Dec 2025 18:00:44 +0330
Subject: [PATCH 2/2] fix filesystem for other platforms

---
 common/platform/filesystem/file.go       |  2 +
 common/platform/filesystem/file_other.go | 54 ++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 common/platform/filesystem/file_other.go

diff --git a/common/platform/filesystem/file.go b/common/platform/filesystem/file.go
index f7f434ded3f4..ebe9b0f10be0 100644
--- a/common/platform/filesystem/file.go
+++ b/common/platform/filesystem/file.go
@@ -1,3 +1,5 @@
+//go:build !windows && !wasm
+
 package filesystem
 
 import (
diff --git a/common/platform/filesystem/file_other.go b/common/platform/filesystem/file_other.go
new file mode 100644
index 000000000000..d3cbdcc7b8c6
--- /dev/null
+++ b/common/platform/filesystem/file_other.go
@@ -0,0 +1,54 @@
+//go:build windows || wasm
+
+package filesystem
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/xtls/xray-core/common/buf"
+	"github.com/xtls/xray-core/common/platform"
+)
+
+type FileReaderFunc func(path string) (io.ReadCloser, error)
+
+var NewFileReader FileReaderFunc = func(path string) (io.ReadCloser, error) {
+	return os.Open(path)
+}
+
+func ReadFile(path string) ([]byte, error) {
+	reader, err := NewFileReader(path)
+	if err != nil {
+		return nil, err
+	}
+	defer reader.Close()
+
+	return buf.ReadAllToBytes(reader)
+}
+
+func ReadAsset(file string) ([]byte, error) {
+	return ReadFile(platform.GetAssetLocation(file))
+}
+
+func ReadCert(file string) ([]byte, error) {
+	if filepath.IsAbs(file) {
+		return ReadFile(file)
+	}
+	return ReadFile(platform.GetCertLocation(file))
+}
+
+func CopyFile(dst string, src string) error {
+	bytes, err := ReadFile(src)
+	if err != nil {
+		return err
+	}
+	f, err := os.OpenFile(dst, os.O_CREATE|os.O_WRONLY, 0o644)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	_, err = f.Write(bytes)
+	return err
+}