96 lines
1.8 KiB
Go
96 lines
1.8 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 && !windows
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package mmap
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import (
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"fmt"
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fsutils "github.com/TeaOSLab/EdgeNode/internal/utils/fs"
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"io"
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"os"
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"runtime"
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"sync/atomic"
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"syscall"
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)
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var totalMMAPFileSize int64
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func TotalMMAPFileSize() int64 {
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return atomic.LoadInt64(&totalMMAPFileSize)
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}
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// OpenFile memory-maps the file pointer for reading.
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func OpenFile(f *os.File, size int64) (r *ReaderAt, err error) {
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// update stat
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atomic.AddInt64(&totalMMAPFileSize, size)
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defer func() {
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if r == nil {
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atomic.AddInt64(&totalMMAPFileSize, -size)
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}
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}()
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defer func() {
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_ = f.Close()
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}()
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if size == 0 {
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return &ReaderAt{
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data: make([]byte, 0),
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}, nil
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}
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if size < 0 {
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return nil, fmt.Errorf("mmap: file %q has negative size", f.Name())
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}
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if size != int64(int(size)) {
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return nil, fmt.Errorf("mmap: file %q is too large", f.Name())
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}
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fsutils.ReaderLimiter.Ack()
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data, err := syscall.Mmap(int(f.Fd()), 0, int(size), syscall.PROT_READ, MMAPReadFlags)
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fsutils.ReaderLimiter.Release()
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if err != nil {
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return nil, err
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}
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r = &ReaderAt{
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data: data,
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size: size,
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}
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runtime.SetFinalizer(r, (*ReaderAt).Close)
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return r, nil
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}
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func (r *ReaderAt) Write(writer io.Writer, offset int) (int, error) {
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var l = len(r.data)
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const segmentSize = 16 << 10
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if l-offset <= segmentSize {
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return writer.Write(r.data[offset:])
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}
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var n int
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for {
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var n1 int
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var err error
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fsutils.ReaderLimiter.Ack()
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if offset+segmentSize <= l {
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n1, err = writer.Write(r.data[offset : offset+segmentSize])
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} else {
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n1, err = writer.Write(r.data[offset:])
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}
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fsutils.ReaderLimiter.Release()
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n += n1
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offset += n1
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if err != nil {
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return n, err
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}
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if offset >= l {
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break
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}
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}
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return n, nil
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}
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