Initial commit (code only without large binaries)

EdgeNode/internal/utils/readers/readers_concurrent_file.go

@@ -0,0 +1,117 @@
+// Copyright 2023 GoEdge CDN goedge.cdn@gmail.com. All rights reserved. Official site: https://goedge.cn .
+
+package readers
+
+import (
+	"github.com/TeaOSLab/EdgeNode/internal/utils/zero"
+	"io"
+	"os"
+	"sync"
+)
+
+type subFileReader struct {
+	fp             *os.File
+	notify         chan zero.Zero
+	parentIsClosed bool
+}
+
+func newSubFileReader(fp *os.File) *subFileReader {
+	return &subFileReader{
+		fp:     fp,
+		notify: make(chan zero.Zero, 2),
+	}
+}
+
+func (this *subFileReader) Read(p []byte) (n int, err error) {
+	n, err = this.fp.Read(p)
+	if n > 0 {
+		return n, nil
+	}
+	if err != nil {
+		if this.parentIsClosed {
+			return
+		}
+
+		if err != io.EOF {
+			return
+		}
+
+		// try next read
+		<-this.notify
+		return this.Read(p)
+	}
+	return
+}
+
+func (this *subFileReader) Close() error {
+	close(this.notify)
+	return this.fp.Close()
+}
+
+func (this *subFileReader) NotifyRead() {
+	select {
+	case this.notify <- zero.Zero{}:
+	default:
+	}
+}
+
+func (this *subFileReader) NotifyClose() {
+	select {
+	case this.notify <- zero.Zero{}:
+	default:
+	}
+	this.parentIsClosed = true
+}
+
+type ConcurrentFileReaders struct {
+	filePath string
+	isClosed bool
+
+	subReaders []*subFileReader
+	locker     sync.RWMutex
+}
+
+func NewConcurrentFileReaders(filePath string) *ConcurrentFileReaders {
+	return &ConcurrentFileReaders{
+		filePath: filePath,
+	}
+}
+
+func (this *ConcurrentFileReaders) Get() (io.ReadCloser, error) {
+	this.locker.Lock()
+	if this.isClosed {
+		this.locker.Unlock()
+		return nil, os.ErrNotExist
+	}
+	this.locker.Unlock()
+
+	fp, err := os.OpenFile(this.filePath, os.O_RDONLY, 0444)
+	if err != nil {
+		return nil, os.ErrNotExist
+	}
+	var subReader = newSubFileReader(fp)
+	this.locker.Lock()
+	this.subReaders = append(this.subReaders, subReader)
+	this.locker.Unlock()
+	return subReader, nil
+}
+
+func (this *ConcurrentFileReaders) NotifyRead() {
+	this.locker.RLock()
+	for _, subReader := range this.subReaders {
+		subReader.NotifyRead()
+	}
+	this.locker.RUnlock()
+}
+
+func (this *ConcurrentFileReaders) NotifyClose() {
+	this.locker.Lock()
+	this.isClosed = true
+	this.locker.Unlock()
+
+	this.locker.RLock()
+	for _, subReader := range this.subReaders {
+		subReader.NotifyClose()
+	}
+	this.locker.RUnlock()
+}