1.4.5.2

EdgeNode/internal/utils/mmap/shared_mmap.go

@@ -0,0 +1,89 @@
+// Copyright 2024 GoEdge CDN goedge.cdn@gmail.com. All rights reserved. Official site: https://goedge.cn .
+//go:build plus
+
+package mmap
+
+import (
+	"io"
+	"os"
+)
+
+type SharedMMAP struct {
+	filename  string
+	stat      os.FileInfo
+	rawReader *ReaderAt
+	countRefs int32
+	mod       uint64
+}
+
+func NewSharedMMAP(filename string, stat os.FileInfo, reader *ReaderAt, mod uint64) *SharedMMAP {
+	return &SharedMMAP{
+		filename:  filename,
+		stat:      stat,
+		rawReader: reader,
+		countRefs: 1,
+		mod:       mod,
+	}
+}
+
+func (this *SharedMMAP) ReadAt(p []byte, off int64) (n int, err error) {
+	n, err = this.rawReader.ReadAt(p, off)
+	return
+}
+
+func (this *SharedMMAP) Size() int64 {
+	return this.stat.Size()
+}
+
+func (this *SharedMMAP) Stat() os.FileInfo {
+	return this.stat
+}
+
+func (this *SharedMMAP) Name() string {
+	return this.filename
+}
+
+// AddRef increase one reference
+func (this *SharedMMAP) AddRef() (ok bool) {
+	mmapMapMu[this.mod].Lock()
+	if this.countRefs > 0 { // not closing
+		this.countRefs++
+		ok = true
+	}
+	mmapMapMu[this.mod].Unlock()
+
+	return
+}
+
+func (this *SharedMMAP) Write(writer io.Writer, offset int) (int, error) {
+	return this.rawReader.Write(writer, offset)
+}
+
+// Close release one reference
+// 单个引用 必须 只能close一次，防止提前close
+func (this *SharedMMAP) Close() error {
+	if !enableShareMode {
+		return this.rawReader.Close()
+	}
+
+	mmapMapMu[this.mod].Lock()
+
+	this.countRefs--
+	var shouldClose = this.countRefs == 0
+
+	if shouldClose {
+		var mmapMap = mmapMaps[this.mod]
+		delete(mmapMap[this.filename], this)
+		if len(mmapMap[this.filename]) == 0 {
+			delete(mmapMap, this.filename)
+		}
+	}
+
+	mmapMapMu[this.mod].Unlock()
+
+	if shouldClose {
+		return this.rawReader.Close()
+	}
+
+	return nil
+}