// The filepath package uses either forward slashes or backslashes,
// depending on the operating system. To process paths such as URLs
// that always use forward slashes regardless of the operating
-// system, see the path package.
+// system, see the [path] package.
package filepath
import (
"errors"
"io/fs"
"os"
+ "slices"
"sort"
"strings"
)
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]
// by purely lexical processing. It applies the following rules
// iteratively until no further processing can be done:
//
-// 1. Replace multiple Separator elements with a single one.
-// 2. Eliminate each . path name element (the current directory).
-// 3. Eliminate each inner .. path name element (the parent directory)
-// along with the non-.. element that precedes it.
-// 4. Eliminate .. elements that begin a rooted path:
-// that is, replace "/.." by "/" at the beginning of a path,
-// assuming Separator is '/'.
+// 1. Replace multiple Separator elements with a single one.
+// 2. Eliminate each . path name element (the current directory).
+// 3. Eliminate each inner .. path name element (the parent directory)
+// along with the non-.. element that precedes it.
+// 4. Eliminate .. elements that begin a rooted path:
+// that is, replace "/.." by "/" at the beginning of a path,
+// assuming Separator is '/'.
//
// The returned path ends in a slash only if it represents a root directory,
// such as "/" on Unix or `C:\` on Windows.
// If the result of this process is an empty string, Clean
// returns the string ".".
//
-// See also Rob Pike, ``Lexical File Names in Plan 9 or
-// Getting Dot-Dot Right,''
+// On Windows, Clean does not modify the volume name other than to replace
+// occurrences of "/" with `\`.
+// For example, Clean("//host/share/../x") returns `\\host\share\x`.
+//
+// See also Rob Pike, “Lexical File Names in Plan 9 or
+// 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 && originalPath[1] != ':' {
+ if volLen > 1 && os.IsPathSeparator(originalPath[0]) && os.IsPathSeparator(originalPath[1]) {
// should be UNC
return FromSlash(originalPath)
}
out.append('.')
}
+ postClean(&out) // avoid creating absolute paths on Windows
return FromSlash(out.string())
}
+// IsLocal reports whether path, using lexical analysis only, has all of these properties:
+//
+// - is within the subtree rooted at the directory in which path is evaluated
+// - is not an absolute path
+// - is not empty
+// - on Windows, is not a reserved name such as "NUL"
+//
+// If IsLocal(path) returns true, then
+// Join(base, path) will always produce a path contained within base and
+// Clean(path) will always produce an unrooted path with no ".." path elements.
+//
+// IsLocal is a purely lexical operation.
+// 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
+}
+
// ToSlash returns the result of replacing each separator character
// in path with a slash ('/') character. Multiple separators are
// replaced by multiple slashes.
targ = targ[len(targVol):]
if base == "." {
base = ""
+ } else if base == "" && volumeNameLen(baseVol) > 2 /* isUNC */ {
+ // Treat any targetpath matching `\\host\share` basepath as absolute path.
+ base = string(Separator)
}
+
// Can't use IsAbs - `\a` and `a` are both relative in Windows.
baseSlashed := len(base) > 0 && base[0] == Separator
targSlashed := len(targ) > 0 && targ[0] == Separator
// SkipDir is used as a return value from WalkFuncs to indicate that
// the directory named in the call is to be skipped. It is not returned
// as an error by any function.
-var SkipDir = errors.New("skip this directory")
+var SkipDir error = fs.SkipDir
-// WalkDirFunc is the type of the function called by WalkDir to visit
-// each each file or directory.
-//
-// The path argument contains the argument to Walk as a prefix.
-// That is, if Walk is called with root argument "dir" and finds a file
-// named "a" in that directory, the walk function will be called with
-// argument "dir/a".
-//
-// The directory and file are joined with Join, which may clean the
-// directory name: if Walk is called with the root argument "x/../dir"
-// and finds a file named "a" in that directory, the walk function will
-// be called with argument "dir/a", not "x/../dir/a".
-//
-// The d argument is the fs.DirEntry for the named path.
-//
-// The error result returned by the function controls how WalkDir
-// continues. If the function returns the special value SkipDir, WalkDir
-// skips the current directory (path if d.IsDir() is true, otherwise
-// path's parent directory). Otherwise, if the function returns a non-nil
-// error, WalkDir stops entirely and returns that error.
-//
-// The err argument reports an error related to path, signaling that
-// WalkDir will not walk into that directory. The function can decide how
-// to handle that error; as described earlier, returning the error will
-// cause WalkDir to stop walking the entire tree.
-//
-// WalkDir calls the function with a non-nil err argument in two cases.
-//
-// First, if the initial os.Lstat on the root directory fails, WalkDir
-// calls the function with path set to root, d set to nil, and err set to
-// the error from os.Lstat.
-//
-// Second, if a directory's ReadDir method fails, WalkDir calls the
-// function with path set to the directory's path, d set to an
-// fs.DirEntry describing the directory, and err set to the error from
-// ReadDir. In this second case, the function is called twice with the
-// path of the directory: the first call is before the directory read is
-// attempted and has err set to nil, giving the function a chance to
-// return SkipDir and avoid the ReadDir entirely. The second call is
-// after a failed ReadDir and reports the error from ReadDir.
-// (If ReadDir succeeds, there is no second call.)
-//
-// The differences between WalkDirFunc compared to WalkFunc are:
-//
-// - The second argument has type fs.DirEntry instead of fs.FileInfo.
-// - The function is called before reading a directory, to allow SkipDir
-// to bypass the directory read entirely.
-// - If a directory read fails, the function is called a second time
-// for that directory to report the error.
-//
-type WalkDirFunc func(path string, d fs.DirEntry, err error) error
+// SkipAll is used as a return value from WalkFuncs to indicate that
+// all remaining files and directories are to be skipped. It is not returned
+// as an error by any function.
+var SkipAll error = fs.SkipAll
-// WalkFunc is the type of the function called by Walk to visit each each
+// WalkFunc is the type of the function called by Walk to visit each
// file or directory.
//
// The path argument contains the argument to Walk as a prefix.
// The error result returned by the function controls how Walk continues.
// If the function returns the special value SkipDir, Walk skips the
// current directory (path if info.IsDir() is true, otherwise path's
-// parent directory). Otherwise, if the function returns a non-nil error,
-// Walk stops entirely and returns that error.
+// parent directory). If the function returns the special value SkipAll,
+// Walk skips all remaining files and directories. Otherwise, if the function
+// returns a non-nil error, Walk stops entirely and returns that error.
//
// The err argument reports an error related to path, signaling that Walk
// will not walk into that directory. The function can decide how to
var lstat = os.Lstat // for testing
// walkDir recursively descends path, calling walkDirFn.
-func walkDir(path string, d fs.DirEntry, walkDirFn WalkDirFunc) error {
+func walkDir(path string, d fs.DirEntry, walkDirFn fs.WalkDirFunc) error {
if err := walkDirFn(path, d, nil); err != nil || !d.IsDir() {
if err == SkipDir && d.IsDir() {
// Successfully skipped directory.
return err
}
- dirs, err := readDir(path)
+ dirs, err := os.ReadDir(path)
if err != nil {
// Second call, to report ReadDir error.
err = walkDirFn(path, d, err)
if err != nil {
+ if err == SkipDir && d.IsDir() {
+ err = nil
+ }
return err
}
}
if err != nil || err1 != nil {
// The caller's behavior is controlled by the return value, which is decided
// by walkFn. walkFn may ignore err and return nil.
- // If walkFn returns SkipDir, it will be handled by the caller.
+ // If walkFn returns SkipDir or SkipAll, it will be handled by the caller.
// So walk should return whatever walkFn returns.
return err1
}
// directory in the tree, including root.
//
// All errors that arise visiting files and directories are filtered by fn:
-// see the WalkDirFunc documentation for details.
+// see the fs.WalkDirFunc documentation for details.
//
// The files are walked in lexical order, which makes the output deterministic
// but requires WalkDir to read an entire directory into memory before proceeding
// to walk that directory.
//
// WalkDir does not follow symbolic links.
-func WalkDir(root string, fn WalkDirFunc) error {
+//
+// WalkDir calls fn with paths that use the separator character appropriate
+// for the operating system. This is unlike [io/fs.WalkDir], which always
+// uses slash separated paths.
+func WalkDir(root string, fn fs.WalkDirFunc) error {
info, err := os.Lstat(root)
if err != nil {
err = fn(root, nil, err)
} else {
- err = walkDir(root, &dirEntryFromInfo{info}, fn)
+ err = walkDir(root, fs.FileInfoToDirEntry(info), fn)
}
- if err == SkipDir {
+ if err == SkipDir || err == SkipAll {
return nil
}
return err
}
-type dirEntryFromInfo struct {
- fs.FileInfo
-}
-
-func (e *dirEntryFromInfo) Type() fs.FileMode {
- return e.Mode().Type()
-}
-
-func (e *dirEntryFromInfo) Info() (fs.FileInfo, error) {
- return e.FileInfo, nil
-}
-
// Walk walks the file tree rooted at root, calling fn for each file or
// directory in the tree, including root.
//
} else {
err = walk(root, info, fn)
}
- if err == SkipDir {
+ if err == SkipDir || err == SkipAll {
return nil
}
return err
}
-// readDir reads the directory named by dirname and returns
-// a sorted list of directory entries.
-func readDir(dirname string) ([]fs.DirEntry, error) {
- f, err := os.Open(dirname)
- if err != nil {
- return nil, err
- }
- dirs, err := f.ReadDir(-1)
- f.Close()
- if err != nil {
- return nil, err
- }
- sort.Slice(dirs, func(i, j int) bool { return dirs[i].Name() < dirs[j].Name() })
- return dirs, nil
-}
-
// readDirNames reads the directory named by dirname and returns
// a sorted list of directory entry names.
func readDirNames(dirname string) ([]string, error) {
// Given "\\host\share\foo" it returns "\\host\share".
// On other platforms it returns "".
func VolumeName(path string) string {
- return path[:volumeNameLen(path)]
+ return FromSlash(path[:volumeNameLen(path)])
}