databricks-cli/libs/filer/fs.go

152 lines
2.7 KiB
Go
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package filer
import (
"bytes"
"context"
"io"
"io/fs"
)
// filerFS implements the fs.FS interface for a filer.
type filerFS struct {
ctx context.Context
filer Filer
}
// NewFS returns an fs.FS backed by a filer.
func NewFS(ctx context.Context, filer Filer) fs.FS {
return &filerFS{ctx: ctx, filer: filer}
}
func (fs *filerFS) Open(name string) (fs.File, error) {
stat, err := fs.filer.Stat(fs.ctx, name)
if err != nil {
return nil, err
}
if stat.IsDir() {
return &fsDir{fs: fs, name: name, stat: stat}, nil
}
return &fsFile{fs: fs, name: name, stat: stat}, nil
}
func (fs *filerFS) ReadDir(name string) ([]fs.DirEntry, error) {
return fs.filer.ReadDir(fs.ctx, name)
}
func (fs *filerFS) ReadFile(name string) ([]byte, error) {
reader, err := fs.filer.Read(fs.ctx, name)
if err != nil {
return nil, err
}
var buf bytes.Buffer
_, err = io.Copy(&buf, reader)
if err != nil {
return nil, err
}
return buf.Bytes(), nil
}
func (fs *filerFS) Stat(name string) (fs.FileInfo, error) {
return fs.filer.Stat(fs.ctx, name)
}
// Type that implements fs.File for a filer-backed fs.FS.
type fsFile struct {
fs *filerFS
name string
stat fs.FileInfo
reader io.Reader
}
func (f *fsFile) Stat() (fs.FileInfo, error) {
return f.stat, nil
}
func (f *fsFile) Read(buf []byte) (int, error) {
if f.reader == nil {
reader, err := f.fs.filer.Read(f.fs.ctx, f.name)
if err != nil {
return 0, err
}
f.reader = reader
}
return f.reader.Read(buf)
}
func (f *fsFile) Close() error {
if f.reader == nil {
return fs.ErrClosed
}
f.reader = nil
return nil
}
// Type that implements fs.ReadDirFile for a filer-backed fs.FS.
type fsDir struct {
fs *filerFS
name string
stat fs.FileInfo
open bool
entries []fs.DirEntry
}
func (f *fsDir) Stat() (fs.FileInfo, error) {
return f.stat, nil
}
func (f *fsDir) Read(buf []byte) (int, error) {
return 0, fs.ErrInvalid
}
func (f *fsDir) ReadDir(n int) ([]fs.DirEntry, error) {
// Load all directory entries if not already loaded.
if !f.open {
entries, err := f.fs.ReadDir(f.name)
if err != nil {
return nil, err
}
f.open = true
f.entries = entries
}
// Return all entries if n <= 0.
if n <= 0 {
entries := f.entries
f.entries = nil
return entries, nil
}
// If there are no more entries, return io.EOF.
if len(f.entries) == 0 {
return nil, io.EOF
}
// If there are less than n entries, return all entries.
if len(f.entries) < n {
entries := f.entries
f.entries = nil
return entries, nil
}
// Return n entries.
entries := f.entries[:n]
f.entries = f.entries[n:]
return entries, nil
}
func (f *fsDir) Close() error {
if !f.open {
return fs.ErrClosed
}
f.open = false
f.entries = nil
return nil
}