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abab0d4197
- Restyles tailfs -> tailFS - Defines interfaces for main TailFS types - Moves implemenatation of TailFS into tailfsimpl package Updates tailscale/corp#16827 Signed-off-by: Percy Wegmann <percy@tailscale.com>
112 lines
2.6 KiB
Go
112 lines
2.6 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// Package shared contains types and functions shared by different tailfs
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// packages.
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package shared
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import (
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"errors"
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"io"
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"io/fs"
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"sync"
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)
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// DirFile implements webdav.File for a virtual directory.
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// It mimics the behavior of an os.File that is pointing at a real directory.
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type DirFile struct {
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// Info provides the fs.FileInfo for this directory
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Info fs.FileInfo
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// LoadChildren is used to load the fs.FileInfos for this directory's
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// children. It is called at most once in order to support listing
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// children.
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LoadChildren func() ([]fs.FileInfo, error)
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// loadChildrenMu guards children and loadedChildren.
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loadChildrenMu sync.Mutex
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children []fs.FileInfo
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loadedChildren bool
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}
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// Readdir implements interface webdav.File. It lazily loads information about
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// children when it is called.
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func (d *DirFile) Readdir(count int) ([]fs.FileInfo, error) {
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err := d.loadChildrenIfNecessary()
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if err != nil {
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return nil, err
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}
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if count <= 0 {
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result := d.children
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d.children = nil
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return result, nil
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}
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n := len(d.children)
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if count < n {
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n = count
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}
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result := d.children[:n]
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d.children = d.children[n:]
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if len(d.children) == 0 {
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err = io.EOF
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}
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return result, err
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}
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func (d *DirFile) loadChildrenIfNecessary() error {
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d.loadChildrenMu.Lock()
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defer d.loadChildrenMu.Unlock()
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if !d.loadedChildren {
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var err error
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d.children, err = d.LoadChildren()
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if err != nil {
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return err
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}
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d.loadedChildren = true
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}
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return nil
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}
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// Stat implements interface webdav.File.
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func (d *DirFile) Stat() (fs.FileInfo, error) {
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return d.Info, nil
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}
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// Close implements interface webdav.File. It does nothing and never returns an
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// error.
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func (d *DirFile) Close() error {
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return nil
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}
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// Read implements interface webdav.File. As this is a directory, it always
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// fails with an fs.PathError.
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func (d *DirFile) Read(b []byte) (int, error) {
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return 0, &fs.PathError{
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Op: "read",
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Path: d.Info.Name(),
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Err: errors.New("is a directory"),
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}
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}
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// Write implements interface webdav.File. As this is a directory, it always
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// fails with an fs.PathError.
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func (d *DirFile) Write(b []byte) (int, error) {
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return 0, &fs.PathError{
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Op: "write",
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Path: d.Info.Name(),
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Err: errors.New("bad file descriptor"),
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}
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}
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// Seek implements interface webdav.File. As this is a directory, it always
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// fails with an fs.PathError.
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func (d *DirFile) Seek(offset int64, whence int) (int64, error) {
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return 0, &fs.PathError{
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Op: "seek",
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Path: d.Info.Name(),
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Err: errors.New("invalid argument"),
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}
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}
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