From: Damien Neil Date: Wed, 24 Apr 2024 17:58:56 +0000 (-0700) Subject: path/filepath, internal/filepathlite: move parts of filepath to filepathlite X-Git-Tag: go1.23rc1~507 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=ceef0633b3c5bbf5d17a12d6e663c136b30b3f36;p=gostls13.git path/filepath, internal/filepathlite: move parts of filepath to filepathlite The path/filepath package needs to depend on the os package to implement Abs, Walk, and other functions. Move the implementation of purely lexical functions from path/filepath into internal/filepathlite, so they can be used by os and other low-level packages. Change-Id: Id211e547d6f1f58c82419695ff2d75cd6cd14a12 Reviewed-on: https://go-review.googlesource.com/c/go/+/566556 Reviewed-by: Behroz Karimpor Reviewed-by: Ian Lance Taylor LUCI-TryBot-Result: Go LUCI --- diff --git a/src/internal/filepathlite/path.go b/src/internal/filepathlite/path.go index b452987b6b..e3daa447d9 100644 --- a/src/internal/filepathlite/path.go +++ b/src/internal/filepathlite/path.go @@ -1,26 +1,274 @@ -// Copyright 2022 The Go Authors. All rights reserved. +// Copyright 2024 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 filepathlite manipulates operating-system file paths. +// Package filepathlite implements a subset of path/filepath, +// only using packages which may be imported by "os". +// +// Tests for these functions are in path/filepath. package filepathlite import ( "errors" + "internal/stringslite" "io/fs" + "slices" ) var errInvalidPath = errors.New("invalid path") +// A lazybuf is a lazily constructed path buffer. +// It supports append, reading previously appended bytes, +// and retrieving the final string. It does not allocate a buffer +// to hold the output until that output diverges from s. +type lazybuf struct { + path string + buf []byte + w int + volAndPath string + volLen int +} + +func (b *lazybuf) index(i int) byte { + if b.buf != nil { + return b.buf[i] + } + return b.path[i] +} + +func (b *lazybuf) append(c byte) { + if b.buf == nil { + if b.w < len(b.path) && b.path[b.w] == c { + b.w++ + return + } + b.buf = make([]byte, len(b.path)) + copy(b.buf, b.path[:b.w]) + } + b.buf[b.w] = c + b.w++ +} + +func (b *lazybuf) prepend(prefix ...byte) { + b.buf = slices.Insert(b.buf, 0, prefix...) + b.w += len(prefix) +} + +func (b *lazybuf) string() string { + if b.buf == nil { + return b.volAndPath[:b.volLen+b.w] + } + return b.volAndPath[:b.volLen] + string(b.buf[:b.w]) +} + +// Clean is filepath.Clean. +func Clean(path string) string { + originalPath := path + volLen := volumeNameLen(path) + path = path[volLen:] + if path == "" { + if volLen > 1 && IsPathSeparator(originalPath[0]) && IsPathSeparator(originalPath[1]) { + // should be UNC + return FromSlash(originalPath) + } + return originalPath + "." + } + rooted := IsPathSeparator(path[0]) + + // Invariants: + // reading from path; r is index of next byte to process. + // writing to buf; w is index of next byte to write. + // dotdot is index in buf where .. must stop, either because + // it is the leading slash or it is a leading ../../.. prefix. + n := len(path) + out := lazybuf{path: path, volAndPath: originalPath, volLen: volLen} + r, dotdot := 0, 0 + if rooted { + out.append(Separator) + r, dotdot = 1, 1 + } + + for r < n { + switch { + case IsPathSeparator(path[r]): + // empty path element + r++ + case path[r] == '.' && (r+1 == n || IsPathSeparator(path[r+1])): + // . element + r++ + case path[r] == '.' && path[r+1] == '.' && (r+2 == n || IsPathSeparator(path[r+2])): + // .. element: remove to last separator + r += 2 + switch { + case out.w > dotdot: + // can backtrack + out.w-- + for out.w > dotdot && !IsPathSeparator(out.index(out.w)) { + out.w-- + } + case !rooted: + // cannot backtrack, but not rooted, so append .. element. + if out.w > 0 { + out.append(Separator) + } + out.append('.') + out.append('.') + dotdot = out.w + } + default: + // real path element. + // add slash if needed + if rooted && out.w != 1 || !rooted && out.w != 0 { + out.append(Separator) + } + // copy element + for ; r < n && !IsPathSeparator(path[r]); r++ { + out.append(path[r]) + } + } + } + + // Turn empty string into "." + if out.w == 0 { + out.append('.') + } + + postClean(&out) // avoid creating absolute paths on Windows + return FromSlash(out.string()) +} + +// IsLocal is filepath.IsLocal. +func IsLocal(path string) bool { + return isLocal(path) +} + +func unixIsLocal(path string) bool { + if IsAbs(path) || path == "" { + return false + } + hasDots := false + for p := path; p != ""; { + var part string + part, p, _ = stringslite.Cut(p, "/") + if part == "." || part == ".." { + hasDots = true + break + } + } + if hasDots { + path = Clean(path) + } + if path == ".." || stringslite.HasPrefix(path, "../") { + return false + } + return true +} + // Localize is filepath.Localize. -// -// It is implemented in this package to avoid a dependency cycle -// between os and file/filepath. -// -// Tests for this function are in path/filepath. func Localize(path string) (string, error) { if !fs.ValidPath(path) { return "", errInvalidPath } return localize(path) } + +// ToSlash is filepath.ToSlash. +func ToSlash(path string) string { + if Separator == '/' { + return path + } + return replaceStringByte(path, Separator, '/') +} + +// FromSlash is filepath.ToSlash. +func FromSlash(path string) string { + if Separator == '/' { + return path + } + return replaceStringByte(path, '/', Separator) +} + +func replaceStringByte(s string, old, new byte) string { + if stringslite.IndexByte(s, old) == -1 { + return s + } + n := []byte(s) + for i := range n { + if n[i] == old { + n[i] = new + } + } + return string(n) +} + +// Split is filepath.Split. +func Split(path string) (dir, file string) { + vol := VolumeName(path) + i := len(path) - 1 + for i >= len(vol) && !IsPathSeparator(path[i]) { + i-- + } + return path[:i+1], path[i+1:] +} + +// Ext is filepath.Ext. +func Ext(path string) string { + for i := len(path) - 1; i >= 0 && !IsPathSeparator(path[i]); i-- { + if path[i] == '.' { + return path[i:] + } + } + return "" +} + +// Base is filepath.Base. +func Base(path string) string { + if path == "" { + return "." + } + // Strip trailing slashes. + for len(path) > 0 && IsPathSeparator(path[len(path)-1]) { + path = path[0 : len(path)-1] + } + // Throw away volume name + path = path[len(VolumeName(path)):] + // Find the last element + i := len(path) - 1 + for i >= 0 && !IsPathSeparator(path[i]) { + i-- + } + if i >= 0 { + path = path[i+1:] + } + // If empty now, it had only slashes. + if path == "" { + return string(Separator) + } + return path +} + +// Dir is filepath.Dir. +func Dir(path string) string { + vol := VolumeName(path) + i := len(path) - 1 + for i >= len(vol) && !IsPathSeparator(path[i]) { + i-- + } + dir := Clean(path[len(vol) : i+1]) + if dir == "." && len(vol) > 2 { + // must be UNC + return vol + } + return vol + dir +} + +// VolumeName is filepath.VolumeName. +func VolumeName(path string) string { + return FromSlash(path[:volumeNameLen(path)]) +} + +// VolumeNameLen returns the length of the leading volume name on Windows. +// It returns 0 elsewhere. +func VolumeNameLen(path string) int { + return volumeNameLen(path) +} diff --git a/src/path/filepath/path_nonwindows.go b/src/internal/filepathlite/path_nonwindows.go similarity index 91% rename from src/path/filepath/path_nonwindows.go rename to src/internal/filepathlite/path_nonwindows.go index db69f0228b..c9c4c02a3d 100644 --- a/src/path/filepath/path_nonwindows.go +++ b/src/internal/filepathlite/path_nonwindows.go @@ -4,6 +4,6 @@ //go:build !windows -package filepath +package filepathlite func postClean(out *lazybuf) {} diff --git a/src/internal/filepathlite/path_plan9.go b/src/internal/filepathlite/path_plan9.go index 91a95ddb06..5bbb724f91 100644 --- a/src/internal/filepathlite/path_plan9.go +++ b/src/internal/filepathlite/path_plan9.go @@ -1,10 +1,26 @@ -// Copyright 2023 The Go Authors. All rights reserved. +// Copyright 2010 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 filepathlite -import "internal/bytealg" +import ( + "internal/bytealg" + "internal/stringslite" +) + +const ( + Separator = '/' // OS-specific path separator + ListSeparator = '\000' // OS-specific path list separator +) + +func IsPathSeparator(c uint8) bool { + return Separator == c +} + +func isLocal(path string) bool { + return unixIsLocal(path) +} func localize(path string) (string, error) { if path[0] == '#' || bytealg.IndexByteString(path, 0) >= 0 { @@ -12,3 +28,14 @@ func localize(path string) (string, error) { } return path, nil } + +// IsAbs reports whether the path is absolute. +func IsAbs(path string) bool { + return stringslite.HasPrefix(path, "/") || stringslite.HasPrefix(path, "#") +} + +// volumeNameLen returns length of the leading volume name on Windows. +// It returns 0 elsewhere. +func volumeNameLen(path string) int { + return 0 +} diff --git a/src/internal/filepathlite/path_unix.go b/src/internal/filepathlite/path_unix.go index edad20817f..e31f1ae74f 100644 --- a/src/internal/filepathlite/path_unix.go +++ b/src/internal/filepathlite/path_unix.go @@ -1,4 +1,4 @@ -// Copyright 2023 The Go Authors. All rights reserved. +// Copyright 2010 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. @@ -6,7 +6,23 @@ package filepathlite -import "internal/bytealg" +import ( + "internal/bytealg" + "internal/stringslite" +) + +const ( + Separator = '/' // OS-specific path separator + ListSeparator = ':' // OS-specific path list separator +) + +func IsPathSeparator(c uint8) bool { + return Separator == c +} + +func isLocal(path string) bool { + return unixIsLocal(path) +} func localize(path string) (string, error) { if bytealg.IndexByteString(path, 0) >= 0 { @@ -14,3 +30,14 @@ func localize(path string) (string, error) { } return path, nil } + +// IsAbs reports whether the path is absolute. +func IsAbs(path string) bool { + return stringslite.HasPrefix(path, "/") +} + +// volumeNameLen returns length of the leading volume name on Windows. +// It returns 0 elsewhere. +func volumeNameLen(path string) int { + return 0 +} diff --git a/src/internal/filepathlite/path_windows.go b/src/internal/filepathlite/path_windows.go index 3d7290b14c..8f34838a98 100644 --- a/src/internal/filepathlite/path_windows.go +++ b/src/internal/filepathlite/path_windows.go @@ -1,4 +1,4 @@ -// Copyright 2022 The Go Authors. All rights reserved. +// Copyright 2010 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. @@ -6,9 +6,52 @@ package filepathlite import ( "internal/bytealg" + "internal/stringslite" "syscall" ) +const ( + Separator = '\\' // OS-specific path separator + ListSeparator = ';' // OS-specific path list separator +) + +func IsPathSeparator(c uint8) bool { + return c == '\\' || c == '/' +} + +func isLocal(path string) bool { + if path == "" { + return false + } + if IsPathSeparator(path[0]) { + // Path rooted in the current drive. + return false + } + if stringslite.IndexByte(path, ':') >= 0 { + // Colons are only valid when marking a drive letter ("C:foo"). + // Rejecting any path with a colon is conservative but safe. + return false + } + hasDots := false // contains . or .. path elements + for p := path; p != ""; { + var part string + part, p, _ = cutPath(p) + if part == "." || part == ".." { + hasDots = true + } + if isReservedName(part) { + return false + } + } + if hasDots { + path = Clean(path) + } + if path == ".." || stringslite.HasPrefix(path, `..\`) { + return false + } + return true +} + func localize(path string) (string, error) { for i := 0; i < len(path); i++ { switch path[i] { @@ -29,7 +72,7 @@ func localize(path string) (string, error) { element = p[:i] p = p[i+1:] } - if IsReservedName(element) { + if isReservedName(element) { return "", errInvalidPath } } @@ -46,12 +89,12 @@ func localize(path string) (string, error) { return path, nil } -// IsReservedName reports if name is a Windows reserved device name. +// isReservedName reports if name is a Windows reserved device name. // It does not detect names with an extension, which are also reserved on some Windows versions. // // For details, search for PRN in // https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file. -func IsReservedName(name string) bool { +func isReservedName(name string) bool { // Device names can have arbitrary trailing characters following a dot or colon. base := name for i := 0; i < len(base); i++ { @@ -134,3 +177,153 @@ func toUpper(c byte) byte { } return c } + +// IsAbs reports whether the path is absolute. +func IsAbs(path string) (b bool) { + l := volumeNameLen(path) + if l == 0 { + return false + } + // If the volume name starts with a double slash, this is an absolute path. + if IsPathSeparator(path[0]) && IsPathSeparator(path[1]) { + return true + } + path = path[l:] + if path == "" { + return false + } + return IsPathSeparator(path[0]) +} + +// volumeNameLen returns length of the leading volume name on Windows. +// It returns 0 elsewhere. +// +// See: +// https://learn.microsoft.com/en-us/dotnet/standard/io/file-path-formats +// https://googleprojectzero.blogspot.com/2016/02/the-definitive-guide-on-win32-to-nt.html +func volumeNameLen(path string) int { + switch { + case len(path) >= 2 && path[1] == ':': + // Path starts with a drive letter. + // + // Not all Windows functions necessarily enforce the requirement that + // drive letters be in the set A-Z, and we don't try to here. + // + // We don't handle the case of a path starting with a non-ASCII character, + // in which case the "drive letter" might be multiple bytes long. + return 2 + + case len(path) == 0 || !IsPathSeparator(path[0]): + // Path does not have a volume component. + return 0 + + case pathHasPrefixFold(path, `\\.\UNC`): + // We're going to treat the UNC host and share as part of the volume + // prefix for historical reasons, but this isn't really principled; + // Windows's own GetFullPathName will happily remove the first + // component of the path in this space, converting + // \\.\unc\a\b\..\c into \\.\unc\a\c. + return uncLen(path, len(`\\.\UNC\`)) + + case pathHasPrefixFold(path, `\\.`) || + pathHasPrefixFold(path, `\\?`) || pathHasPrefixFold(path, `\??`): + // Path starts with \\.\, and is a Local Device path; or + // path starts with \\?\ or \??\ and is a Root Local Device path. + // + // We treat the next component after the \\.\ prefix as + // part of the volume name, which means Clean(`\\?\c:\`) + // won't remove the trailing \. (See #64028.) + if len(path) == 3 { + return 3 // exactly \\. + } + _, rest, ok := cutPath(path[4:]) + if !ok { + return len(path) + } + return len(path) - len(rest) - 1 + + case len(path) >= 2 && IsPathSeparator(path[1]): + // Path starts with \\, and is a UNC path. + return uncLen(path, 2) + } + return 0 +} + +// pathHasPrefixFold tests whether the path s begins with prefix, +// ignoring case and treating all path separators as equivalent. +// If s is longer than prefix, then s[len(prefix)] must be a path separator. +func pathHasPrefixFold(s, prefix string) bool { + if len(s) < len(prefix) { + return false + } + for i := 0; i < len(prefix); i++ { + if IsPathSeparator(prefix[i]) { + if !IsPathSeparator(s[i]) { + return false + } + } else if toUpper(prefix[i]) != toUpper(s[i]) { + return false + } + } + if len(s) > len(prefix) && !IsPathSeparator(s[len(prefix)]) { + return false + } + return true +} + +// uncLen returns the length of the volume prefix of a UNC path. +// prefixLen is the prefix prior to the start of the UNC host; +// for example, for "//host/share", the prefixLen is len("//")==2. +func uncLen(path string, prefixLen int) int { + count := 0 + for i := prefixLen; i < len(path); i++ { + if IsPathSeparator(path[i]) { + count++ + if count == 2 { + return i + } + } + } + return len(path) +} + +// cutPath slices path around the first path separator. +func cutPath(path string) (before, after string, found bool) { + for i := range path { + if IsPathSeparator(path[i]) { + return path[:i], path[i+1:], true + } + } + return path, "", false +} + +// isUNC reports whether path is a UNC path. +func isUNC(path string) bool { + return len(path) > 1 && IsPathSeparator(path[0]) && IsPathSeparator(path[1]) +} + +// postClean adjusts the results of Clean to avoid turning a relative path +// into an absolute or rooted one. +func postClean(out *lazybuf) { + if out.volLen != 0 || out.buf == nil { + return + } + // If a ':' appears in the path element at the start of a path, + // insert a .\ at the beginning to avoid converting relative paths + // like a/../c: into c:. + for _, c := range out.buf { + if IsPathSeparator(c) { + break + } + if c == ':' { + out.prepend('.', Separator) + return + } + } + // If a path begins with \??\, insert a \. at the beginning + // to avoid converting paths like \a\..\??\c:\x into \??\c:\x + // (equivalent to c:\x). + if len(out.buf) >= 3 && IsPathSeparator(out.buf[0]) && out.buf[1] == '?' && out.buf[2] == '?' { + out.prepend(Separator, '.') + } +} diff --git a/src/path/filepath/match.go b/src/path/filepath/match.go index 12f0bfa7d3..67124796db 100644 --- a/src/path/filepath/match.go +++ b/src/path/filepath/match.go @@ -6,6 +6,7 @@ package filepath import ( "errors" + "internal/filepathlite" "os" "runtime" "sort" @@ -307,7 +308,7 @@ func cleanGlobPath(path string) string { // cleanGlobPathWindows is windows version of cleanGlobPath. func cleanGlobPathWindows(path string) (prefixLen int, cleaned string) { - vollen := volumeNameLen(path) + vollen := filepathlite.VolumeNameLen(path) switch { case path == "": return 0, "." diff --git a/src/path/filepath/path.go b/src/path/filepath/path.go index cd70c2b318..b0f3cbbfe9 100644 --- a/src/path/filepath/path.go +++ b/src/path/filepath/path.go @@ -13,58 +13,13 @@ package filepath import ( "errors" + "internal/bytealg" "internal/filepathlite" "io/fs" "os" - "slices" "sort" - "strings" ) -// A lazybuf is a lazily constructed path buffer. -// It supports append, reading previously appended bytes, -// and retrieving the final string. It does not allocate a buffer -// to hold the output until that output diverges from s. -type lazybuf struct { - path string - buf []byte - w int - volAndPath string - volLen int -} - -func (b *lazybuf) index(i int) byte { - if b.buf != nil { - return b.buf[i] - } - return b.path[i] -} - -func (b *lazybuf) append(c byte) { - if b.buf == nil { - if b.w < len(b.path) && b.path[b.w] == c { - b.w++ - return - } - b.buf = make([]byte, len(b.path)) - copy(b.buf, b.path[:b.w]) - } - b.buf[b.w] = c - b.w++ -} - -func (b *lazybuf) prepend(prefix ...byte) { - b.buf = slices.Insert(b.buf, 0, prefix...) - b.w += len(prefix) -} - -func (b *lazybuf) string() string { - if b.buf == nil { - return b.volAndPath[:b.volLen+b.w] - } - return b.volAndPath[:b.volLen] + string(b.buf[:b.w]) -} - const ( Separator = os.PathSeparator ListSeparator = os.PathListSeparator @@ -98,78 +53,7 @@ const ( // Getting Dot-Dot Right,” // https://9p.io/sys/doc/lexnames.html func Clean(path string) string { - originalPath := path - volLen := volumeNameLen(path) - path = path[volLen:] - if path == "" { - if volLen > 1 && os.IsPathSeparator(originalPath[0]) && os.IsPathSeparator(originalPath[1]) { - // should be UNC - return FromSlash(originalPath) - } - return originalPath + "." - } - rooted := os.IsPathSeparator(path[0]) - - // Invariants: - // reading from path; r is index of next byte to process. - // writing to buf; w is index of next byte to write. - // dotdot is index in buf where .. must stop, either because - // it is the leading slash or it is a leading ../../.. prefix. - n := len(path) - out := lazybuf{path: path, volAndPath: originalPath, volLen: volLen} - r, dotdot := 0, 0 - if rooted { - out.append(Separator) - r, dotdot = 1, 1 - } - - for r < n { - switch { - case os.IsPathSeparator(path[r]): - // empty path element - r++ - case path[r] == '.' && (r+1 == n || os.IsPathSeparator(path[r+1])): - // . element - r++ - case path[r] == '.' && path[r+1] == '.' && (r+2 == n || os.IsPathSeparator(path[r+2])): - // .. element: remove to last separator - r += 2 - switch { - case out.w > dotdot: - // can backtrack - out.w-- - for out.w > dotdot && !os.IsPathSeparator(out.index(out.w)) { - out.w-- - } - case !rooted: - // cannot backtrack, but not rooted, so append .. element. - if out.w > 0 { - out.append(Separator) - } - out.append('.') - out.append('.') - dotdot = out.w - } - default: - // real path element. - // add slash if needed - if rooted && out.w != 1 || !rooted && out.w != 0 { - out.append(Separator) - } - // copy element - for ; r < n && !os.IsPathSeparator(path[r]); r++ { - out.append(path[r]) - } - } - } - - // Turn empty string into "." - if out.w == 0 { - out.append('.') - } - - postClean(&out) // avoid creating absolute paths on Windows - return FromSlash(out.string()) + return filepathlite.Clean(path) } // IsLocal reports whether path, using lexical analysis only, has all of these properties: @@ -187,29 +71,7 @@ func Clean(path string) string { // In particular, it does not account for the effect of any symbolic links // that may exist in the filesystem. func IsLocal(path string) bool { - return isLocal(path) -} - -func unixIsLocal(path string) bool { - if IsAbs(path) || path == "" { - return false - } - hasDots := false - for p := path; p != ""; { - var part string - part, p, _ = strings.Cut(p, "/") - if part == "." || part == ".." { - hasDots = true - break - } - } - if hasDots { - path = Clean(path) - } - if path == ".." || strings.HasPrefix(path, "../") { - return false - } - return true + return filepathlite.IsLocal(path) } // Localize converts a slash-separated path into an operating system path. @@ -228,10 +90,7 @@ func Localize(path string) (string, error) { // in path with a slash ('/') character. Multiple separators are // replaced by multiple slashes. func ToSlash(path string) string { - if Separator == '/' { - return path - } - return strings.ReplaceAll(path, string(Separator), "/") + return filepathlite.ToSlash(path) } // FromSlash returns the result of replacing each slash ('/') character @@ -241,10 +100,7 @@ func ToSlash(path string) string { // See also the Localize function, which converts a slash-separated path // as used by the io/fs package to an operating system path. func FromSlash(path string) string { - if Separator == '/' { - return path - } - return strings.ReplaceAll(path, "/", string(Separator)) + return filepathlite.FromSlash(path) } // SplitList splits a list of paths joined by the OS-specific [ListSeparator], @@ -261,12 +117,7 @@ func SplitList(path string) []string { // and file set to path. // The returned values have the property that path = dir+file. func Split(path string) (dir, file string) { - vol := VolumeName(path) - i := len(path) - 1 - for i >= len(vol) && !os.IsPathSeparator(path[i]) { - i-- - } - return path[:i+1], path[i+1:] + return filepathlite.Split(path) } // Join joins any number of path elements into a single path, @@ -285,12 +136,7 @@ func Join(elem ...string) string { // in the final element of path; it is empty if there is // no dot. func Ext(path string) string { - for i := len(path) - 1; i >= 0 && !os.IsPathSeparator(path[i]); i-- { - if path[i] == '.' { - return path[i:] - } - } - return "" + return filepathlite.Ext(path) } // EvalSymlinks returns the path name after the evaluation of any symbolic @@ -302,6 +148,11 @@ func EvalSymlinks(path string) (string, error) { return evalSymlinks(path) } +// IsAbs reports whether the path is absolute. +func IsAbs(path string) bool { + return filepathlite.IsAbs(path) +} + // Abs returns an absolute representation of path. // If the path is not absolute it will be joined with the current // working directory to turn it into an absolute path. The absolute @@ -342,7 +193,7 @@ func Rel(basepath, targpath string) (string, error) { targ = targ[len(targVol):] if base == "." { base = "" - } else if base == "" && volumeNameLen(baseVol) > 2 /* isUNC */ { + } else if base == "" && filepathlite.VolumeNameLen(baseVol) > 2 /* isUNC */ { // Treat any targetpath matching `\\host\share` basepath as absolute path. base = string(Separator) } @@ -381,7 +232,7 @@ func Rel(basepath, targpath string) (string, error) { } if b0 != bl { // Base elements left. Must go up before going down. - seps := strings.Count(base[b0:bl], string(Separator)) + seps := bytealg.CountString(base[b0:bl], Separator) size := 2 + seps*3 if tl != t0 { size += 1 + tl - t0 @@ -602,28 +453,7 @@ func readDirNames(dirname string) ([]string, error) { // If the path is empty, Base returns ".". // If the path consists entirely of separators, Base returns a single separator. func Base(path string) string { - if path == "" { - return "." - } - // Strip trailing slashes. - for len(path) > 0 && os.IsPathSeparator(path[len(path)-1]) { - path = path[0 : len(path)-1] - } - // Throw away volume name - path = path[len(VolumeName(path)):] - // Find the last element - i := len(path) - 1 - for i >= 0 && !os.IsPathSeparator(path[i]) { - i-- - } - if i >= 0 { - path = path[i+1:] - } - // If empty now, it had only slashes. - if path == "" { - return string(Separator) - } - return path + return filepathlite.Base(path) } // Dir returns all but the last element of path, typically the path's directory. @@ -633,17 +463,7 @@ func Base(path string) string { // If the path consists entirely of separators, Dir returns a single separator. // The returned path does not end in a separator unless it is the root directory. func Dir(path string) string { - vol := VolumeName(path) - i := len(path) - 1 - for i >= len(vol) && !os.IsPathSeparator(path[i]) { - i-- - } - dir := Clean(path[len(vol) : i+1]) - if dir == "." && len(vol) > 2 { - // must be UNC - return vol - } - return vol + dir + return filepathlite.Dir(path) } // VolumeName returns leading volume name. @@ -651,5 +471,5 @@ func Dir(path string) string { // Given "\\host\share\foo" it returns "\\host\share". // On other platforms it returns "". func VolumeName(path string) string { - return FromSlash(path[:volumeNameLen(path)]) + return filepathlite.VolumeName(path) } diff --git a/src/path/filepath/path_plan9.go b/src/path/filepath/path_plan9.go index 453206aee3..0e5147b90b 100644 --- a/src/path/filepath/path_plan9.go +++ b/src/path/filepath/path_plan9.go @@ -4,22 +4,9 @@ package filepath -import "strings" - -func isLocal(path string) bool { - return unixIsLocal(path) -} - -// IsAbs reports whether the path is absolute. -func IsAbs(path string) bool { - return strings.HasPrefix(path, "/") || strings.HasPrefix(path, "#") -} - -// volumeNameLen returns length of the leading volume name on Windows. -// It returns 0 elsewhere. -func volumeNameLen(path string) int { - return 0 -} +import ( + "strings" +) // HasPrefix exists for historical compatibility and should not be used. // diff --git a/src/path/filepath/path_unix.go b/src/path/filepath/path_unix.go index 57e6217434..6bc974db3f 100644 --- a/src/path/filepath/path_unix.go +++ b/src/path/filepath/path_unix.go @@ -6,22 +6,9 @@ package filepath -import "strings" - -func isLocal(path string) bool { - return unixIsLocal(path) -} - -// IsAbs reports whether the path is absolute. -func IsAbs(path string) bool { - return strings.HasPrefix(path, "/") -} - -// volumeNameLen returns length of the leading volume name on Windows. -// It returns 0 elsewhere. -func volumeNameLen(path string) int { - return 0 -} +import ( + "strings" +) // HasPrefix exists for historical compatibility and should not be used. // diff --git a/src/path/filepath/path_windows.go b/src/path/filepath/path_windows.go index 44037c45ac..d53f87f1ac 100644 --- a/src/path/filepath/path_windows.go +++ b/src/path/filepath/path_windows.go @@ -1,179 +1,11 @@ -// Copyright 2010 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 filepath import ( - "internal/filepathlite" "os" "strings" "syscall" ) -func isSlash(c uint8) bool { - return c == '\\' || c == '/' -} - -func toUpper(c byte) byte { - if 'a' <= c && c <= 'z' { - return c - ('a' - 'A') - } - return c -} - -func isLocal(path string) bool { - if path == "" { - return false - } - if isSlash(path[0]) { - // Path rooted in the current drive. - return false - } - if strings.IndexByte(path, ':') >= 0 { - // Colons are only valid when marking a drive letter ("C:foo"). - // Rejecting any path with a colon is conservative but safe. - return false - } - hasDots := false // contains . or .. path elements - for p := path; p != ""; { - var part string - part, p, _ = cutPath(p) - if part == "." || part == ".." { - hasDots = true - } - if filepathlite.IsReservedName(part) { - return false - } - } - if hasDots { - path = Clean(path) - } - if path == ".." || strings.HasPrefix(path, `..\`) { - return false - } - return true -} - -// IsAbs reports whether the path is absolute. -func IsAbs(path string) (b bool) { - l := volumeNameLen(path) - if l == 0 { - return false - } - // If the volume name starts with a double slash, this is an absolute path. - if isSlash(path[0]) && isSlash(path[1]) { - return true - } - path = path[l:] - if path == "" { - return false - } - return isSlash(path[0]) -} - -// volumeNameLen returns length of the leading volume name on Windows. -// It returns 0 elsewhere. -// -// See: -// https://learn.microsoft.com/en-us/dotnet/standard/io/file-path-formats -// https://googleprojectzero.blogspot.com/2016/02/the-definitive-guide-on-win32-to-nt.html -func volumeNameLen(path string) int { - switch { - case len(path) >= 2 && path[1] == ':': - // Path starts with a drive letter. - // - // Not all Windows functions necessarily enforce the requirement that - // drive letters be in the set A-Z, and we don't try to here. - // - // We don't handle the case of a path starting with a non-ASCII character, - // in which case the "drive letter" might be multiple bytes long. - return 2 - - case len(path) == 0 || !isSlash(path[0]): - // Path does not have a volume component. - return 0 - - case pathHasPrefixFold(path, `\\.\UNC`): - // We're going to treat the UNC host and share as part of the volume - // prefix for historical reasons, but this isn't really principled; - // Windows's own GetFullPathName will happily remove the first - // component of the path in this space, converting - // \\.\unc\a\b\..\c into \\.\unc\a\c. - return uncLen(path, len(`\\.\UNC\`)) - - case pathHasPrefixFold(path, `\\.`) || - pathHasPrefixFold(path, `\\?`) || pathHasPrefixFold(path, `\??`): - // Path starts with \\.\, and is a Local Device path; or - // path starts with \\?\ or \??\ and is a Root Local Device path. - // - // We treat the next component after the \\.\ prefix as - // part of the volume name, which means Clean(`\\?\c:\`) - // won't remove the trailing \. (See #64028.) - if len(path) == 3 { - return 3 // exactly \\. - } - _, rest, ok := cutPath(path[4:]) - if !ok { - return len(path) - } - return len(path) - len(rest) - 1 - - case len(path) >= 2 && isSlash(path[1]): - // Path starts with \\, and is a UNC path. - return uncLen(path, 2) - } - return 0 -} - -// pathHasPrefixFold tests whether the path s begins with prefix, -// ignoring case and treating all path separators as equivalent. -// If s is longer than prefix, then s[len(prefix)] must be a path separator. -func pathHasPrefixFold(s, prefix string) bool { - if len(s) < len(prefix) { - return false - } - for i := 0; i < len(prefix); i++ { - if isSlash(prefix[i]) { - if !isSlash(s[i]) { - return false - } - } else if toUpper(prefix[i]) != toUpper(s[i]) { - return false - } - } - if len(s) > len(prefix) && !isSlash(s[len(prefix)]) { - return false - } - return true -} - -// uncLen returns the length of the volume prefix of a UNC path. -// prefixLen is the prefix prior to the start of the UNC host; -// for example, for "//host/share", the prefixLen is len("//")==2. -func uncLen(path string, prefixLen int) int { - count := 0 - for i := prefixLen; i < len(path); i++ { - if isSlash(path[i]) { - count++ - if count == 2 { - return i - } - } - } - return len(path) -} - -// cutPath slices path around the first path separator. -func cutPath(path string) (before, after string, found bool) { - for i := range path { - if isSlash(path[i]) { - return path[:i], path[i+1:], true - } - } - return path, "", false -} - // HasPrefix exists for historical compatibility and should not be used. // // Deprecated: HasPrefix does not respect path boundaries and @@ -237,7 +69,7 @@ func join(elem []string) string { switch { case b.Len() == 0: // Add the first non-empty path element unchanged. - case isSlash(lastChar): + case os.IsPathSeparator(lastChar): // If the path ends in a slash, strip any leading slashes from the next // path element to avoid creating a UNC path (any path starting with "\\") // from non-UNC elements. @@ -245,13 +77,13 @@ func join(elem []string) string { // The correct behavior for Join when the first element is an incomplete UNC // path (for example, "\\") is underspecified. We currently join subsequent // elements so Join("\\", "host", "share") produces "\\host\share". - for len(e) > 0 && isSlash(e[0]) { + for len(e) > 0 && os.IsPathSeparator(e[0]) { e = e[1:] } // If the path is \ and the next path element is ??, // add an extra .\ to create \.\?? rather than \??\ // (a Root Local Device path). - if b.Len() == 1 && pathHasPrefixFold(e, "??") { + if b.Len() == 1 && strings.HasPrefix(e, "??") && (len(e) == len("??") || os.IsPathSeparator(e[2])) { b.WriteString(`.\`) } case lastChar == ':': @@ -280,29 +112,3 @@ func join(elem []string) string { func sameWord(a, b string) bool { return strings.EqualFold(a, b) } - -// postClean adjusts the results of Clean to avoid turning a relative path -// into an absolute or rooted one. -func postClean(out *lazybuf) { - if out.volLen != 0 || out.buf == nil { - return - } - // If a ':' appears in the path element at the start of a path, - // insert a .\ at the beginning to avoid converting relative paths - // like a/../c: into c:. - for _, c := range out.buf { - if os.IsPathSeparator(c) { - break - } - if c == ':' { - out.prepend('.', Separator) - return - } - } - // If a path begins with \??\, insert a \. at the beginning - // to avoid converting paths like \a\..\??\c:\x into \??\c:\x - // (equivalent to c:\x). - if len(out.buf) >= 3 && os.IsPathSeparator(out.buf[0]) && out.buf[1] == '?' && out.buf[2] == '?' { - out.prepend(Separator, '.') - } -} diff --git a/src/path/filepath/symlink.go b/src/path/filepath/symlink.go index f9435e0d5b..a6047ae444 100644 --- a/src/path/filepath/symlink.go +++ b/src/path/filepath/symlink.go @@ -6,6 +6,7 @@ package filepath import ( "errors" + "internal/filepathlite" "io/fs" "os" "runtime" @@ -13,7 +14,7 @@ import ( ) func walkSymlinks(path string) (string, error) { - volLen := volumeNameLen(path) + volLen := filepathlite.VolumeNameLen(path) pathSeparator := string(os.PathSeparator) if volLen < len(path) && os.IsPathSeparator(path[volLen]) { @@ -34,7 +35,7 @@ func walkSymlinks(path string) (string, error) { // On Windows, "." can be a symlink. // We look it up, and use the value if it is absolute. // If not, we just return ".". - isWindowsDot := runtime.GOOS == "windows" && path[volumeNameLen(path):] == "." + isWindowsDot := runtime.GOOS == "windows" && path[filepathlite.VolumeNameLen(path):] == "." // The next path component is in path[start:end]. if end == start { @@ -73,7 +74,7 @@ func walkSymlinks(path string) (string, error) { // Ordinary path component. Add it to result. - if len(dest) > volumeNameLen(dest) && !os.IsPathSeparator(dest[len(dest)-1]) { + if len(dest) > filepathlite.VolumeNameLen(dest) && !os.IsPathSeparator(dest[len(dest)-1]) { dest += pathSeparator } @@ -113,7 +114,7 @@ func walkSymlinks(path string) (string, error) { path = link + path[end:] - v := volumeNameLen(link) + v := filepathlite.VolumeNameLen(link) if v > 0 { // Symlink to drive name is an absolute path. if v < len(link) && os.IsPathSeparator(link[v]) {