forked from TrueCloudLab/restic
153 lines
3 KiB
Go
153 lines
3 KiB
Go
// +build !openbsd
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// +build !windows
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package fuse
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import (
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"sync"
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"github.com/restic/restic"
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"github.com/restic/restic/backend"
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"github.com/restic/restic/pack"
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"bazil.org/fuse"
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"bazil.org/fuse/fs"
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"golang.org/x/net/context"
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)
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// The default block size to report in stat
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const blockSize = 512
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// Statically ensure that *file implements the given interface
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var _ = fs.HandleReader(&file{})
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var _ = fs.HandleReleaser(&file{})
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// BlobLoader is an abstracted repository with a reduced set of methods used
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// for fuse operations.
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type BlobLoader interface {
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LookupBlobSize(backend.ID) (uint, error)
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LoadBlob(pack.BlobType, backend.ID, []byte) ([]byte, error)
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}
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type file struct {
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repo BlobLoader
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node *restic.Node
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ownerIsRoot bool
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sizes []uint
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blobs [][]byte
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}
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const defaultBlobSize = 128 * 1024
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var blobPool = sync.Pool{
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New: func() interface{} {
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return make([]byte, defaultBlobSize)
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},
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}
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func newFile(repo BlobLoader, node *restic.Node, ownerIsRoot bool) (*file, error) {
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sizes := make([]uint, len(node.Content))
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for i, id := range node.Content {
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size, err := repo.LookupBlobSize(id)
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if err != nil {
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return nil, err
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}
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sizes[i] = size
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}
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return &file{
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repo: repo,
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node: node,
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sizes: sizes,
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blobs: make([][]byte, len(node.Content)),
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ownerIsRoot: ownerIsRoot,
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}, nil
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}
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func (f *file) Attr(ctx context.Context, a *fuse.Attr) error {
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a.Inode = f.node.Inode
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a.Mode = f.node.Mode
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a.Size = f.node.Size
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a.Blocks = (f.node.Size / blockSize) + 1
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a.BlockSize = blockSize
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if !f.ownerIsRoot {
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a.Uid = f.node.UID
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a.Gid = f.node.GID
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}
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a.Atime = f.node.AccessTime
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a.Ctime = f.node.ChangeTime
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a.Mtime = f.node.ModTime
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return nil
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}
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func (f *file) getBlobAt(i int) (blob []byte, err error) {
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if f.blobs[i] != nil {
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return f.blobs[i], nil
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}
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buf := blobPool.Get().([]byte)
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buf = buf[:cap(buf)]
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if uint(len(buf)) < f.sizes[i] {
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if len(buf) > defaultBlobSize {
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blobPool.Put(buf)
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}
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buf = make([]byte, f.sizes[i])
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}
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blob, err = f.repo.LoadBlob(pack.Data, f.node.Content[i], buf)
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if err != nil {
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return nil, err
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}
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f.blobs[i] = blob
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return blob, nil
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}
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func (f *file) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
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offset := req.Offset
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// Skip blobs before the offset
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startContent := 0
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for offset > int64(f.sizes[startContent]) {
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offset -= int64(f.sizes[startContent])
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startContent++
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}
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dst := resp.Data[0:req.Size]
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readBytes := 0
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remainingBytes := req.Size
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for i := startContent; remainingBytes > 0 && i < len(f.sizes); i++ {
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blob, err := f.getBlobAt(i)
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if err != nil {
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return err
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}
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if offset > 0 {
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blob = blob[offset:len(blob)]
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offset = 0
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}
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copied := copy(dst, blob)
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remainingBytes -= copied
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readBytes += copied
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dst = dst[copied:]
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}
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resp.Data = resp.Data[:readBytes]
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return nil
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}
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func (f *file) Release(ctx context.Context, req *fuse.ReleaseRequest) error {
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for i := range f.blobs {
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if f.blobs[i] != nil {
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blobPool.Put(f.blobs[i])
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f.blobs[i] = nil
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}
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}
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return nil
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}
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