syncthing/lib/scanner/infinitefs_test.go
Jakob Borg d6fbfc3545 lib/fs, lib/model, lib/scanner: Make scans cancellable (fixes #3965)
The folder already knew how to stop properly, but the fs.Walk() didn't
and can potentially take a very long time. This adds context support to
Walk and the underlying scanning stuff, and passes in an appropriate
context from above. The stop channel in model.folder is replaced with a
context for this purpose.

To test I added an infiniteFS that represents a large amount of data
(not actually infinite, but close) and verify that walking it is
properly stopped. For that to be implemented smoothly I moved out the
Walk function to it's own type, as typically the implementer of a new
filesystem type might not need or want to reimplement Walk.

It's somewhat tricky to test that this actually works properly on the
actual sendReceiveFolder and so on, as those are started from inside the
model and the filesystem isn't easily pluggable etc. Instead I've tested
that part manually by adding a huge folder and verifying that pause,
resume and reconfig do the right things by looking at debug output.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4117
2017-04-26 00:15:23 +00:00

104 lines
3.6 KiB
Go

// Copyright (C) 2017 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package scanner
import (
"errors"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"time"
"github.com/syncthing/syncthing/lib/fs"
)
type infiniteFS struct {
width int // number of files and directories per level
depth int // number of tree levels to simulate
filesize int64 // size of each file in bytes
}
var errNotSupp = errors.New("not supported")
func (i infiniteFS) Lstat(name string) (fs.FileInfo, error) {
return fakeInfo{name, i.filesize}, nil
}
func (i infiniteFS) DirNames(name string) ([]string, error) {
// Returns a list of fake files and directories. Names are such that
// files appear before directories - this makes it so the scanner will
// actually see a few files without having to reach the max depth.
var names []string
for j := 0; j < i.width; j++ {
names = append(names, fmt.Sprintf("aa-file-%d", j))
}
if len(strings.Split(name, string(os.PathSeparator))) < i.depth {
for j := 0; j < i.width; j++ {
names = append(names, fmt.Sprintf("zz-dir-%d", j))
}
}
return names, nil
}
func (i infiniteFS) Open(name string) (fs.File, error) {
return &fakeFile{name, i.filesize, 0}, nil
}
func (infiniteFS) Chmod(name string, mode fs.FileMode) error { return errNotSupp }
func (infiniteFS) Chtimes(name string, atime time.Time, mtime time.Time) error { return errNotSupp }
func (infiniteFS) Create(name string) (fs.File, error) { return nil, errNotSupp }
func (infiniteFS) CreateSymlink(name, target string) error { return errNotSupp }
func (infiniteFS) Mkdir(name string, perm fs.FileMode) error { return errNotSupp }
func (infiniteFS) ReadSymlink(name string) (string, error) { return "", errNotSupp }
func (infiniteFS) Remove(name string) error { return errNotSupp }
func (infiniteFS) Rename(oldname, newname string) error { return errNotSupp }
func (infiniteFS) Stat(name string) (fs.FileInfo, error) { return nil, errNotSupp }
func (infiniteFS) SymlinksSupported() bool { return false }
func (infiniteFS) Walk(root string, walkFn fs.WalkFunc) error { return errNotSupp }
type fakeInfo struct {
name string
size int64
}
func (f fakeInfo) Name() string { return f.name }
func (f fakeInfo) Mode() fs.FileMode { return 0755 }
func (f fakeInfo) Size() int64 { return f.size }
func (f fakeInfo) ModTime() time.Time { return time.Unix(1234567890, 0) }
func (f fakeInfo) IsDir() bool { return strings.Contains(filepath.Base(f.name), "dir") }
func (f fakeInfo) IsRegular() bool { return !f.IsDir() }
func (f fakeInfo) IsSymlink() bool { return false }
type fakeFile struct {
name string
size int64
readOffset int64
}
func (f *fakeFile) Read(bs []byte) (int, error) {
remaining := f.size - f.readOffset
if remaining == 0 {
return 0, io.EOF
}
if remaining < int64(len(bs)) {
f.readOffset = f.size
return int(remaining), nil
}
f.readOffset += int64(len(bs))
return len(bs), nil
}
func (f *fakeFile) Stat() (fs.FileInfo, error) {
return fakeInfo{f.name, f.size}, nil
}
func (f *fakeFile) WriteAt(bs []byte, offs int64) (int, error) { return 0, errNotSupp }
func (f *fakeFile) Close() error { return nil }
func (f *fakeFile) Truncate(size int64) error { return errNotSupp }