76 lines
1.3 KiB
Go
76 lines
1.3 KiB
Go
package sessionwriter
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import (
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"bufio"
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"io"
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"log"
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"os"
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)
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type File struct {
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file *os.File
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buffer *bufio.Writer
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updated bool
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}
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func NewFile(path string, bufSize int) (*File, error) {
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file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
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if err != nil {
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return nil, err
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}
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return &File{
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file: file,
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buffer: bufio.NewWriterSize(file, bufSize),
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updated: false,
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}, nil
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}
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func (f *File) Write(data []byte) error {
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f.updated = true
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if len(data) > f.buffer.Available()+f.buffer.Size() {
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// Flush buffer to file
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for i := 0; i < 3; i++ {
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err := f.buffer.Flush()
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if err == nil {
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break
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}
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log.Printf("can't flush buffer: %s", err)
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}
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// Write big message directly to file
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return f.write(f.file, data)
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}
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return f.write(f.buffer, data)
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}
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func (f *File) write(w io.Writer, data []byte) error {
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leftToWrite := len(data)
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for leftToWrite > 0 {
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from := len(data) - leftToWrite
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writtenDown, err := w.Write(data[from:])
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if err != nil {
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return err
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}
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leftToWrite -= writtenDown
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}
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return nil
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}
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func (f *File) Sync() error {
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if !f.updated {
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return nil
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}
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if err := f.buffer.Flush(); err != nil {
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return err
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}
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if err := f.file.Sync(); err != nil {
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return err
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}
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f.updated = false
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return nil
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}
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func (f *File) Close() error {
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_ = f.buffer.Flush()
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_ = f.file.Sync()
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return f.file.Close()
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}
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