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author | hiddenpath <hiddenpath@yandex-team.com> | 2024-04-02 23:50:23 +0300 |
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committer | hiddenpath <hiddenpath@yandex-team.com> | 2024-04-03 00:02:31 +0300 |
commit | 8923c6d2c438e0aeed2e06b8b0275e1864eeee33 (patch) | |
tree | 6b5e476699fc0be5091cb650654ef5f602c8afff /contrib/go/_std_1.22/src/io/fs/sub.go | |
parent | d18afd09df2a08cd023012593b46109b77713a6c (diff) | |
download | ydb-8923c6d2c438e0aeed2e06b8b0275e1864eeee33.tar.gz |
Update golang to 1.22.1
2967d19c907adf59101a1f47b4208bd0b04a6186
Diffstat (limited to 'contrib/go/_std_1.22/src/io/fs/sub.go')
-rw-r--r-- | contrib/go/_std_1.22/src/io/fs/sub.go | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/contrib/go/_std_1.22/src/io/fs/sub.go b/contrib/go/_std_1.22/src/io/fs/sub.go new file mode 100644 index 0000000000..9999e63b26 --- /dev/null +++ b/contrib/go/_std_1.22/src/io/fs/sub.go @@ -0,0 +1,138 @@ +// Copyright 2020 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package fs + +import ( + "errors" + "path" +) + +// A SubFS is a file system with a Sub method. +type SubFS interface { + FS + + // Sub returns an FS corresponding to the subtree rooted at dir. + Sub(dir string) (FS, error) +} + +// Sub returns an [FS] corresponding to the subtree rooted at fsys's dir. +// +// If dir is ".", Sub returns fsys unchanged. +// Otherwise, if fs implements [SubFS], Sub returns fsys.Sub(dir). +// Otherwise, Sub returns a new [FS] implementation sub that, +// in effect, implements sub.Open(name) as fsys.Open(path.Join(dir, name)). +// The implementation also translates calls to ReadDir, ReadFile, and Glob appropriately. +// +// Note that Sub(os.DirFS("/"), "prefix") is equivalent to os.DirFS("/prefix") +// and that neither of them guarantees to avoid operating system +// accesses outside "/prefix", because the implementation of [os.DirFS] +// does not check for symbolic links inside "/prefix" that point to +// other directories. That is, [os.DirFS] is not a general substitute for a +// chroot-style security mechanism, and Sub does not change that fact. +func Sub(fsys FS, dir string) (FS, error) { + if !ValidPath(dir) { + return nil, &PathError{Op: "sub", Path: dir, Err: errors.New("invalid name")} + } + if dir == "." { + return fsys, nil + } + if fsys, ok := fsys.(SubFS); ok { + return fsys.Sub(dir) + } + return &subFS{fsys, dir}, nil +} + +type subFS struct { + fsys FS + dir string +} + +// fullName maps name to the fully-qualified name dir/name. +func (f *subFS) fullName(op string, name string) (string, error) { + if !ValidPath(name) { + return "", &PathError{Op: op, Path: name, Err: errors.New("invalid name")} + } + return path.Join(f.dir, name), nil +} + +// shorten maps name, which should start with f.dir, back to the suffix after f.dir. +func (f *subFS) shorten(name string) (rel string, ok bool) { + if name == f.dir { + return ".", true + } + if len(name) >= len(f.dir)+2 && name[len(f.dir)] == '/' && name[:len(f.dir)] == f.dir { + return name[len(f.dir)+1:], true + } + return "", false +} + +// fixErr shortens any reported names in PathErrors by stripping f.dir. +func (f *subFS) fixErr(err error) error { + if e, ok := err.(*PathError); ok { + if short, ok := f.shorten(e.Path); ok { + e.Path = short + } + } + return err +} + +func (f *subFS) Open(name string) (File, error) { + full, err := f.fullName("open", name) + if err != nil { + return nil, err + } + file, err := f.fsys.Open(full) + return file, f.fixErr(err) +} + +func (f *subFS) ReadDir(name string) ([]DirEntry, error) { + full, err := f.fullName("read", name) + if err != nil { + return nil, err + } + dir, err := ReadDir(f.fsys, full) + return dir, f.fixErr(err) +} + +func (f *subFS) ReadFile(name string) ([]byte, error) { + full, err := f.fullName("read", name) + if err != nil { + return nil, err + } + data, err := ReadFile(f.fsys, full) + return data, f.fixErr(err) +} + +func (f *subFS) Glob(pattern string) ([]string, error) { + // Check pattern is well-formed. + if _, err := path.Match(pattern, ""); err != nil { + return nil, err + } + if pattern == "." { + return []string{"."}, nil + } + + full := f.dir + "/" + pattern + list, err := Glob(f.fsys, full) + for i, name := range list { + name, ok := f.shorten(name) + if !ok { + return nil, errors.New("invalid result from inner fsys Glob: " + name + " not in " + f.dir) // can't use fmt in this package + } + list[i] = name + } + return list, f.fixErr(err) +} + +func (f *subFS) Sub(dir string) (FS, error) { + if dir == "." { + return f, nil + } + full, err := f.fullName("sub", dir) + if err != nil { + return nil, err + } + return &subFS{f.fsys, full}, nil +} |