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The Save methods of the BlobSaver, FileSaver and TreeSaver return early on when the archiver is stopped due to an error. For that they select on both the tomb.Dying() and context.Done() channels, which can lead to a race condition when the tomb is killed due to an error: The tomb first closes its Dying channel before canceling all child contexts. Archiver.SaveDir only aborts its execution once the context was canceled. When the tomb killing is paused between closing its Dying channel and canceling the child contexts, this lets the FileSaver/TreeSaver.Save methods return immediately, however, ScanDir still reads further files causing the test case to fail. As a killed tomb always cancels all child contexts and as the Savers always use a context bound to the tomb, it is sufficient to just use context.Done() as escape hatch in the Save functions. This fixes the mismatch between SaveDir and Save. Adjust the tests to use contexts bound to the tomb for all interactions with the Savers.
243 lines
5.2 KiB
Go
243 lines
5.2 KiB
Go
package archiver
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import (
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"context"
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"io"
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"os"
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"github.com/restic/chunker"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/fs"
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"github.com/restic/restic/internal/restic"
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tomb "gopkg.in/tomb.v2"
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)
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// FutureFile is returned by Save and will return the data once it
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// has been processed.
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type FutureFile struct {
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ch <-chan saveFileResponse
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res saveFileResponse
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}
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// Wait blocks until the result of the save operation is received or ctx is
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// cancelled.
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func (s *FutureFile) Wait(ctx context.Context) {
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select {
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case res, ok := <-s.ch:
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if ok {
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s.res = res
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}
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case <-ctx.Done():
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return
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}
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}
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// Node returns the node once it is available.
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func (s *FutureFile) Node() *restic.Node {
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return s.res.node
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}
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// Stats returns the stats for the file once they are available.
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func (s *FutureFile) Stats() ItemStats {
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return s.res.stats
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}
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// Err returns the error in case an error occurred.
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func (s *FutureFile) Err() error {
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return s.res.err
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}
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// SaveBlobFn saves a blob to a repo.
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type SaveBlobFn func(context.Context, restic.BlobType, *Buffer) FutureBlob
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// FileSaver concurrently saves incoming files to the repo.
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type FileSaver struct {
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saveFilePool *BufferPool
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saveBlob SaveBlobFn
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pol chunker.Pol
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ch chan<- saveFileJob
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CompleteBlob func(filename string, bytes uint64)
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NodeFromFileInfo func(filename string, fi os.FileInfo) (*restic.Node, error)
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}
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// NewFileSaver returns a new file saver. A worker pool with fileWorkers is
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// started, it is stopped when ctx is cancelled.
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func NewFileSaver(ctx context.Context, t *tomb.Tomb, save SaveBlobFn, pol chunker.Pol, fileWorkers, blobWorkers uint) *FileSaver {
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ch := make(chan saveFileJob)
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debug.Log("new file saver with %v file workers and %v blob workers", fileWorkers, blobWorkers)
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poolSize := fileWorkers + blobWorkers
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s := &FileSaver{
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saveBlob: save,
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saveFilePool: NewBufferPool(ctx, int(poolSize), chunker.MaxSize),
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pol: pol,
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ch: ch,
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CompleteBlob: func(string, uint64) {},
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}
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for i := uint(0); i < fileWorkers; i++ {
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t.Go(func() error {
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s.worker(t.Context(ctx), ch)
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return nil
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})
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}
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return s
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}
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// CompleteFunc is called when the file has been saved.
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type CompleteFunc func(*restic.Node, ItemStats)
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// Save stores the file f and returns the data once it has been completed. The
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// file is closed by Save.
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func (s *FileSaver) Save(ctx context.Context, snPath string, file fs.File, fi os.FileInfo, start func(), complete CompleteFunc) FutureFile {
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ch := make(chan saveFileResponse, 1)
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job := saveFileJob{
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snPath: snPath,
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file: file,
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fi: fi,
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start: start,
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complete: complete,
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ch: ch,
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}
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select {
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case s.ch <- job:
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case <-ctx.Done():
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debug.Log("not sending job, context is cancelled: %v", ctx.Err())
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_ = file.Close()
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close(ch)
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return FutureFile{ch: ch}
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}
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return FutureFile{ch: ch}
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}
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type saveFileJob struct {
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snPath string
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file fs.File
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fi os.FileInfo
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ch chan<- saveFileResponse
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complete CompleteFunc
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start func()
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}
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type saveFileResponse struct {
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node *restic.Node
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stats ItemStats
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err error
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}
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// saveFile stores the file f in the repo, then closes it.
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func (s *FileSaver) saveFile(ctx context.Context, chnker *chunker.Chunker, snPath string, f fs.File, fi os.FileInfo, start func()) saveFileResponse {
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start()
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stats := ItemStats{}
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debug.Log("%v", snPath)
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node, err := s.NodeFromFileInfo(f.Name(), fi)
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if err != nil {
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_ = f.Close()
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return saveFileResponse{err: err}
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}
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if node.Type != "file" {
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_ = f.Close()
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return saveFileResponse{err: errors.Errorf("node type %q is wrong", node.Type)}
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}
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// reuse the chunker
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chnker.Reset(f, s.pol)
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var results []FutureBlob
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node.Content = []restic.ID{}
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var size uint64
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for {
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buf := s.saveFilePool.Get()
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chunk, err := chnker.Next(buf.Data)
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if errors.Cause(err) == io.EOF {
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buf.Release()
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break
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}
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buf.Data = chunk.Data
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size += uint64(chunk.Length)
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if err != nil {
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_ = f.Close()
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return saveFileResponse{err: err}
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}
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// test if the context has been cancelled, return the error
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if ctx.Err() != nil {
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_ = f.Close()
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return saveFileResponse{err: ctx.Err()}
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}
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res := s.saveBlob(ctx, restic.DataBlob, buf)
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results = append(results, res)
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// test if the context has been cancelled, return the error
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if ctx.Err() != nil {
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_ = f.Close()
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return saveFileResponse{err: ctx.Err()}
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}
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s.CompleteBlob(f.Name(), uint64(len(chunk.Data)))
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}
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err = f.Close()
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if err != nil {
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return saveFileResponse{err: err}
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}
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for _, res := range results {
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res.Wait(ctx)
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if !res.Known() {
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stats.DataBlobs++
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stats.DataSize += uint64(res.Length())
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}
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node.Content = append(node.Content, res.ID())
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}
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node.Size = size
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return saveFileResponse{
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node: node,
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stats: stats,
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}
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}
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func (s *FileSaver) worker(ctx context.Context, jobs <-chan saveFileJob) {
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// a worker has one chunker which is reused for each file (because it contains a rather large buffer)
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chnker := chunker.New(nil, s.pol)
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for {
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var job saveFileJob
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select {
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case <-ctx.Done():
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return
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case job = <-jobs:
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}
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res := s.saveFile(ctx, chnker, job.snPath, job.file, job.fi, job.start)
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if job.complete != nil {
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job.complete(res.node, res.stats)
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}
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job.ch <- res
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close(job.ch)
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}
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}
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