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XuanwoXuanwo
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pkg: Implement wrapper for fs.FS and http.FileSystem (#538)
* pkg: Implement wrapper for fs.FS Signed-off-by: Xuanwo <github@xuanwo.io> * Rename tp fswrap Signed-off-by: Xuanwo <github@xuanwo.io> * Fix build Signed-off-by: Xuanwo <github@xuanwo.io> * Add convert function Signed-off-by: Xuanwo <github@xuanwo.io>
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‎pkg/fswrap/doc.go‎

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/*
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package iofswrap is a wrapper that convert go-storage services to fs.FS.
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*/
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package fswrap

‎pkg/fswrap/fileinfo.go‎

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package fswrap
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import (
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"os"
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"time"
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"github.com/aos-dev/go-storage/v3/types"
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)
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type fileInfoWrapper struct {
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object *types.Object
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}
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func (o fileInfoWrapper) Name() string {
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return o.object.Path
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}
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func (o fileInfoWrapper) Size() int64 {
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return o.object.MustGetContentLength()
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}
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func (o fileInfoWrapper) Mode() os.FileMode {
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return formatFileMode(o.object.Mode)
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}
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func (o fileInfoWrapper) ModTime() time.Time {
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return o.object.MustGetLastModified()
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}
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func (o fileInfoWrapper) IsDir() bool {
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return o.object.Mode.IsDir()
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}
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// Sys will return internal Object.
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func (o fileInfoWrapper) Sys() interface{} {
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return o.object
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}
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func formatFileMode(om types.ObjectMode) os.FileMode {
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var m os.FileMode
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if om.IsDir() {
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m |= os.ModeDir
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}
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if om.IsAppend() {
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m |= os.ModeAppend
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}
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if om.IsLink() {
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m |= os.ModeSymlink
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}
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return m
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}

‎pkg/fswrap/httpfs.go‎

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package fswrap
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import (
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"bytes"
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"errors"
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"io"
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"net/http"
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"os"
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"github.com/aos-dev/go-storage/v3/pairs"
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"github.com/aos-dev/go-storage/v3/types"
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)
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var (
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_ http.FileSystem = httpFsWrapper{}
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_ http.File = httpFileWrapper{}
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)
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// HttpFs convert a Storager to http.FileSystem
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func HttpFs(s types.Storager) http.FileSystem {
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return httpFsWrapper{s}
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}
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type httpFsWrapper struct {
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store types.Storager
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}
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func (h httpFsWrapper) Open(name string) (http.File, error) {
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o, err := h.store.Stat(name)
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if err != nil {
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return nil, err
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}
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return &httpFileWrapper{store: h.store, object: o}, nil
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}
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type httpFileWrapper struct {
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store types.Storager
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object *types.Object
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offset int64
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buf bytes.Buffer
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}
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func (h httpFileWrapper) Close() error {
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h.store = nil
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h.object = nil
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h.offset = 0
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return nil
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}
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func (h httpFileWrapper) Read(bs []byte) (int, error) {
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size := int64(len(bs))
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n, err := h.store.Read(h.object.Path, &h.buf, pairs.WithSize(size), pairs.WithOffset(h.offset))
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if err != nil {
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return int(n), err
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}
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h.offset += n
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nn := copy(bs, h.buf.Bytes())
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h.buf.Reset() // Reset internal buffer after copy
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return nn, nil
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}
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func (h httpFileWrapper) Seek(offset int64, whence int) (int64, error) {
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size := h.object.MustGetContentLength()
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switch whence {
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case io.SeekStart:
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h.offset = offset
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case io.SeekCurrent:
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h.offset += offset
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case io.SeekEnd:
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// TODO: Do we need to check value here?
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h.offset = size - offset
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}
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return h.offset, nil
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}
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func (h httpFileWrapper) Readdir(count int) ([]os.FileInfo, error) {
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if !h.object.Mode.IsDir() {
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return nil, os.ErrInvalid
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}
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it, err := h.store.List(h.object.Path, pairs.WithListMode(types.ListModeDir))
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if err != nil {
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return nil, err
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}
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// Change the meaning of n for the implementation below.
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//
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// The n above was for the public interface of "if n <= 0,
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// Readdir returns all the FileInfo from the directory in a
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// single slice".
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//
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// But below, we use only negative to mean looping until the
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// end and positive to mean bounded, with positive
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// terminating at 0.
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if count == 0 {
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count = -1
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}
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fi := make([]os.FileInfo, 0)
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for count != 0 {
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o, err := it.Next()
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if err != nil && errors.Is(err, types.IterateDone) {
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break
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}
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if err != nil {
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return nil, err
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}
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fi = append(fi, fileInfoWrapper{o})
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if count > 0 {
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count--
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}
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}
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return fi, nil
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}
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func (h httpFileWrapper) Stat() (os.FileInfo, error) {
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return &fileInfoWrapper{object: h.object}, nil
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}

‎pkg/fswrap/iofs.go‎

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//+build go1.16
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package fswrap
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import (
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"bytes"
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"errors"
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"io/fs"
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"path"
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"github.com/aos-dev/go-storage/v3/pairs"
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"github.com/aos-dev/go-storage/v3/types"
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)
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var (
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_ fs.FS = fsWrapper{}
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_ fs.GlobFS = fsWrapper{}
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_ fs.ReadDirFS = fsWrapper{}
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_ fs.ReadFileFS = fsWrapper{}
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_ fs.StatFS = fsWrapper{}
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_ fs.SubFS = fsWrapper{}
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_ fs.File = &fileWrapper{}
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_ fs.FileInfo = &fileInfoWrapper{}
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_ fs.DirEntry = &dirEntryWrapper{}
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)
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// Fs convert a Storager to fs.FS
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func Fs(s types.Storager) fs.FS {
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return fsWrapper{s}
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}
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type fsWrapper struct {
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store types.Storager
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}
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func (w fsWrapper) Open(name string) (fs.File, error) {
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o, err := w.store.Stat(name)
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if err != nil {
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return nil, err
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}
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return &fileWrapper{store: w.store, object: o}, nil
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}
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func (w fsWrapper) Glob(name string) ([]string, error) {
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it, err := w.store.List("", pairs.WithListMode(types.ListModePrefix))
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if err != nil {
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return nil, err
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}
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s := make([]string, 0)
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for {
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o, err := it.Next()
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if err != nil && errors.Is(err, types.IterateDone) {
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break
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}
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if err != nil {
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return nil, err
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}
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ok, err := path.Match(name, o.Path)
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if err != nil {
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return nil, err
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}
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if ok {
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s = append(s, o.Path)
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}
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}
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return s, nil
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}
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func (w fsWrapper) ReadDir(name string) ([]fs.DirEntry, error) {
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it, err := w.store.List(name, pairs.WithListMode(types.ListModeDir))
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if err != nil {
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return nil, err
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}
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ds := make([]fs.DirEntry, 0)
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for {
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o, err := it.Next()
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if err != nil && errors.Is(err, types.IterateDone) {
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break
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}
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if err != nil {
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return nil, err
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}
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ds = append(ds, dirEntryWrapper{o})
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}
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return ds, nil
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}
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func (w fsWrapper) ReadFile(name string) ([]byte, error) {
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var buf bytes.Buffer
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_, err := w.store.Read(name, &buf)
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if err != nil {
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return nil, err
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}
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return buf.Bytes(), nil
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}
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func (w fsWrapper) Stat(name string) (fs.FileInfo, error) {
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o, err := w.store.Stat(name)
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if err != nil {
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return nil, err
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}
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return &fileInfoWrapper{object: o}, nil
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}
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func (w fsWrapper) Sub(dir string) (fs.FS, error) {
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panic("implement me")
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}
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type fileWrapper struct {
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store types.Storager
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object *types.Object
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offset int64
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buf bytes.Buffer
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}
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func (o fileWrapper) Stat() (fs.FileInfo, error) {
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return &fileInfoWrapper{o.object}, nil
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}
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func (o fileWrapper) Read(bs []byte) (int, error) {
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size := int64(len(bs))
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n, err := o.store.Read(o.object.Path, &o.buf, pairs.WithSize(size), pairs.WithOffset(o.offset))
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if err != nil {
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return int(n), err
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}
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o.offset += n
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nn := copy(bs, o.buf.Bytes())
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o.buf.Reset() // Reset internal buffer after copy
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return nn, nil
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}
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func (o fileWrapper) Close() error {
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o.store = nil
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o.object = nil
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o.offset = 0
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return nil
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}
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type dirEntryWrapper struct {
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object *types.Object
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}
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func (d dirEntryWrapper) Name() string {
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return d.object.Path
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}
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func (d dirEntryWrapper) IsDir() bool {
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return d.object.Mode.IsDir()
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}
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func (d dirEntryWrapper) Type() fs.FileMode {
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return formatFileMode(d.object.Mode)
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}
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func (d dirEntryWrapper) Info() (fs.FileInfo, error) {
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return &fileInfoWrapper{d.object}, nil
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}

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