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