forked from TrueCloudLab/restic
70 lines
1.8 KiB
Go
70 lines
1.8 KiB
Go
package restorer
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import (
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"io"
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"os"
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"sync"
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"github.com/hashicorp/golang-lru/simplelru"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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)
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type filesWriter struct {
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lock sync.Mutex // guards concurrent access
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inprogress map[*fileInfo]struct{} // (logically) opened file writers
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writers simplelru.LRUCache // key: *fileInfo, value: *os.File
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}
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func newFilesWriter(count int) *filesWriter {
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writers, _ := simplelru.NewLRU(count, func(key interface{}, value interface{}) {
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value.(*os.File).Close()
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debug.Log("Closed and purged cached writer for %v", key)
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})
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return &filesWriter{inprogress: make(map[*fileInfo]struct{}), writers: writers}
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}
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func (w *filesWriter) writeToFile(file *fileInfo, buf []byte) error {
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acquireWriter := func() (io.Writer, error) {
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w.lock.Lock()
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defer w.lock.Unlock()
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if wr, ok := w.writers.Get(file); ok {
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debug.Log("Used cached writer for %s", file.path)
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return wr.(*os.File), nil
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}
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var flags int
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if _, append := w.inprogress[file]; append {
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flags = os.O_APPEND | os.O_WRONLY
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} else {
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w.inprogress[file] = struct{}{}
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flags = os.O_CREATE | os.O_TRUNC | os.O_WRONLY
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}
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wr, err := os.OpenFile(file.path, flags, 0600)
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if err != nil {
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return nil, err
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}
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w.writers.Add(file, wr)
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debug.Log("Opened and cached writer for %s", file.path)
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return wr, nil
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}
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wr, err := acquireWriter()
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if err != nil {
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return err
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}
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n, err := wr.Write(buf)
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if err != nil {
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return err
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}
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if n != len(buf) {
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return errors.Errorf("error writing file %v: wrong length written, want %d, got %d", file.path, len(buf), n)
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}
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return nil
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}
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func (w *filesWriter) close(file *fileInfo) {
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w.lock.Lock()
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defer w.lock.Unlock()
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w.writers.Remove(file)
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delete(w.inprogress, file)
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}
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