added Len*, Segment*, Strip* functions to paths

paths/consts.go

@@ -4,6 +4,10 @@ import (
 	"io/fs"
 )
 
+const (
+	GenericSeparator rune = '/'
+)
+
 // Mostly just for reference.
 const (
 	// ModeDir | ModeSymlink | ModeNamedPipe | ModeSocket | ModeDevice | ModeCharDevice | ModeIrregular

paths/funcs.go

@@ -23,6 +23,7 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
+	"math"
 	"os"
 	"os/user"
 	"path"
@@ -42,7 +43,7 @@ import (
 ExpandHome will take a tilde(~)-prefixed path and resolve it to the actual path in-place.
 "Nested" user paths (~someuser/somechroot/~someotheruser) are not supported as home directories are expected to be absolute paths.
 */
-func ExpandHome(path *string) (err error) {
+func ExpandHome(p *string) (err error) {
 
 	var unameSplit []string
 	var uname string
@@ -51,10 +52,10 @@ func ExpandHome(path *string) (err error) {
 
 	// Props to this guy.
 	// https://stackoverflow.com/a/43578461/733214
-	if len(*path) == 0 {
+	if len(*p) == 0 {
 		err = errors.New("empty path")
 		return
-	} else if (*path)[0] != '~' {
+	} else if (*p)[0] != '~' {
 		return
 	}
 
@@ -70,7 +71,7 @@ func ExpandHome(path *string) (err error) {
 		}
 	*/
 	// K but do it smarter.
-	unameSplit = strings.SplitN(*path, string(os.PathSeparator), 2)
+	unameSplit = strings.SplitN(*p, string(os.PathSeparator), 2)
 	if len(unameSplit) != 2 {
 		unameSplit = append(unameSplit, "")
 	}
@@ -86,7 +87,7 @@ func ExpandHome(path *string) (err error) {
 		}
 	}
 
-	*path = filepath.Join(u.HomeDir, unameSplit[1])
+	*p = filepath.Join(u.HomeDir, unameSplit[1])
 
 	return
 }
@@ -108,9 +109,9 @@ potentially returning an inaccurate result.
 
 This is a thin wrapper around GetFirstWithRef.
 */
-func GetFirst(paths []string) (content []byte, isDir, ok bool) {
+func GetFirst(p []string) (content []byte, isDir, ok bool) {
 
-	content, isDir, ok, _ = GetFirstWithRef(paths)
+	content, isDir, ok, _ = GetFirstWithRef(p)
 
 	return
 }
@@ -119,12 +120,12 @@ func GetFirst(paths []string) (content []byte, isDir, ok bool) {
 GetFirstWithRef is the file equivalent of envs.GetFirstWithRef.
 
 It behaves exactly like GetFirst, but with an additional returned value, idx,
-which specifies the index in paths in which a path was found.
+which specifies the index in p in which a path was found.
 
 As always, results are not guaranteed due to permissions, etc.
 potentially returning an inaccurate result.
 */
-func GetFirstWithRef(paths []string) (content []byte, isDir, ok bool, idx int) {
+func GetFirstWithRef(p []string) (content []byte, isDir, ok bool, idx int) {
 
 	var locPaths []string
 	var exists bool
@@ -133,11 +134,11 @@ func GetFirstWithRef(paths []string) (content []byte, isDir, ok bool, idx int) {
 
 	idx = -1
 	// We have to be a little less cavalier about this.
-	if paths == nil {
+	if p == nil {
 		return
 	}
-	locPaths = make([]string, len(paths))
+	locPaths = make([]string, len(p))
-	locPaths = paths[:] // Create an explicit copy so we don't modify paths.
+	locPaths = p[:] // Create an explicit copy so we don't modify p.
 	for i, p := range locPaths {
 		if exists, stat, err = RealPathExistsStat(&p); err != nil {
 			err = nil
@@ -160,6 +161,30 @@ func GetFirstWithRef(paths []string) (content []byte, isDir, ok bool, idx int) {
 	return
 }
 
+/*
+Len returns the number of path segments in p, as split with the same param signature to Segment.
+
+See Segment for details on abs and strict.
+*/
+func Len(p string, abs, strict bool) (segments int) {
+
+	segments = len(Segment(p, abs, strict))
+
+	return
+}
+
+/*
+LenSys returns the number of path segments in p, as split with the same param signature to SegmentSys.
+
+See Segment for details on abs and strict.
+*/
+func LenSys(p string, abs, strict bool) (segments int) {
+
+	segments = len(SegmentSys(p, abs, strict))
+
+	return
+}
+
 /*
 MakeDirIfNotExist will create a directory at a given path if it doesn't exist.
 
@@ -167,11 +192,11 @@ See also the documentation for RealPath.
 
 This is a bit more sane option than os.MkdirAll as it will normalize paths a little better.
 */
-func MakeDirIfNotExist(path string) (err error) {
+func MakeDirIfNotExist(p string) (err error) {
 
 	var stat os.FileInfo
 	var exists bool
-	var locPath string = path
+	var locPath string = p
 
 	if exists, stat, err = RealPathExistsStat(&locPath); err != nil {
 		if !exists {
@@ -208,14 +233,16 @@ It is recommended to check err (if not nil) for an invalid path error. If this i
 path syntax/string itself is not supported on the runtime OS. This can be done via:
 
 	if errors.Is(err, fs.ErrInvalid) {...}
-*/
-func RealPath(path *string) (err error) {
 
-	if err = ExpandHome(path); err != nil {
+RealPath is simply a wrapper around ExpandHome(path) and filepath.Abs(*path).
+*/
+func RealPath(p *string) (err error) {
+
+	if err = ExpandHome(p); err != nil {
 		return
 	}
 
-	if *path, err = filepath.Abs(*path); err != nil {
+	if *p, err = filepath.Abs(*p); err != nil {
 		return
 	}
 
@@ -225,25 +252,25 @@ func RealPath(path *string) (err error) {
 /*
 RealPathJoin combines RealPath with (path).Join.
 
-If dst is nil, then rootPath will be updated with the new value.
+If dst is nil, then p will be updated with the new value.
 You probably don't want that.
 */
-func RealPathJoin(rootPath, dst *string, subPaths ...string) (err error) {
+func RealPathJoin(p, dst *string, subPaths ...string) (err error) {
 
 	var newPath string
 	var realDst *string
 
-	if err = RealPath(rootPath); err != nil {
+	if err = RealPath(p); err != nil {
 		return
 	}
 
 	if dst == nil {
-		realDst = rootPath
+		realDst = p
 	} else {
 		realDst = dst
 	}
 
-	newPath = path.Join(append([]string{*rootPath}, subPaths...)...)
+	newPath = path.Join(append([]string{*p}, subPaths...)...)
 	if err = RealPath(&newPath); err != nil {
 		return
 	}
@@ -259,22 +286,22 @@ RealPathJoinSys combines RealPath with (path/filepath).Join.
 If dst is nil, then path will be updated with the new value.
 You probably don't want that.
 */
-func RealPathJoinSys(path, dst *string, subPaths ...string) (err error) {
+func RealPathJoinSys(p, dst *string, subPaths ...string) (err error) {
 
 	var newPath string
 	var realDst *string
 
-	if err = RealPath(path); err != nil {
+	if err = RealPath(p); err != nil {
 		return
 	}
 
 	if dst == nil {
-		realDst = path
+		realDst = p
 	} else {
 		realDst = dst
 	}
 
-	newPath = filepath.Join(append([]string{*path}, subPaths...)...)
+	newPath = filepath.Join(append([]string{*p}, subPaths...)...)
 	if err = RealPath(&newPath); err != nil {
 		return
 	}
@@ -300,13 +327,13 @@ See also the documentation for RealPath.
 
 In those cases, it may be preferable to use RealPathExistsStat and checking stat for nil.
 */
-func RealPathExists(path *string) (exists bool, err error) {
+func RealPathExists(p *string) (exists bool, err error) {
 
-	if err = RealPath(path); err != nil {
+	if err = RealPath(p); err != nil {
 		return
 	}
 
-	if _, err = os.Stat(*path); err != nil {
+	if _, err = os.Stat(*p); err != nil {
 		if errors.Is(err, fs.ErrNotExist) {
 			err = nil
 		}
@@ -325,13 +352,13 @@ for the path (assuming it exists).
 If stat is nil, it is highly recommended to check err via the methods suggested
 in the documentation for RealPath and RealPathExists.
 */
-func RealPathExistsStat(path *string) (exists bool, stat os.FileInfo, err error) {
+func RealPathExistsStat(p *string) (exists bool, stat os.FileInfo, err error) {
 
-	if exists, err = RealPathExists(path); err != nil {
+	if exists, err = RealPathExists(p); err != nil {
 		return
 	}
 
-	if stat, err = os.Stat(*path); err != nil {
+	if stat, err = os.Stat(*p); err != nil {
 		return
 	}
 
@@ -498,6 +525,124 @@ func SearchFsPathsAsync(matcher FsSearchCriteriaAsync) {
 	return
 }
 
+/*
+Segment returns path p's segments as a slice of strings, using GenericSeparator as a separator.
+
+If abs is true, the placeholder leading prefix(es) (if any) of GenericSeparator will be kept in-place;
+otherwise it/they will be trimmed out.
+e.g.:
+
+	abs == true:  //foo/bar/baz => []string{"", "", "foo", "bar", "baz"}
+	abs == false: /foo/bar/baz => []string{"foo", "bar", "baz"}
+
+If strict is true, any trailing GenericSeparator will be kept in-place;
+otherwise they will be trimmed out.
+e.g. (assuming abs == false):
+
+	strict == true:  /foo/bar/baz// => []string{"foo", "bar", "baz", "", ""}
+	strict == false: /foo/bar/baz/ => []string{"foo", "bar", "baz"}
+
+It is recommended to call RealPath for path's ptr first for normalization.
+*/
+func Segment(p string, abs, strict bool) (segments []string) {
+
+	if !abs {
+		p = strings.TrimLeft(p, string(GenericSeparator))
+	}
+	if !strict {
+		p = strings.TrimRight(p, string(GenericSeparator))
+	}
+
+	segments = strings.Split(p, string(GenericSeparator))
+
+	return
+}
+
+// SegmentSys is exactly like Segment, except using os.PathSeparator instead of GenericSeparator.
+func SegmentSys(p string, abs, strict bool) (segments []string) {
+
+	if !abs {
+		p = strings.TrimLeft(p, string(os.PathSeparator))
+	}
+	if !strict {
+		p = strings.TrimRight(p, string(os.PathSeparator))
+	}
+
+	segments = strings.Split(p, string(os.PathSeparator))
+
+	return
+}
+
+/*
+Strip is like Segment but trims out the leading n number of segments and reassembles the path using path.Join.
+
+n may be negative, in which case the *trailing* n number of segments will be trimmed out.
+(i.e. n == -1, p == `foo/bar/baz/quux` would be `foo/bar/baz`, not `bar/baz/quux`)
+
+If you require more traditional slicing (e.g. with interval),
+you may want to use path.Join with a sliced result of Segment instead.
+e.g.: *only* the *last* n segments: path.Join(Segment(p, ...)[Len(p, ...)-n:]...)
+
+If n == 0 or int(math.Abs(float64(n))) >= len(Segment(p, ...)), no transformation will be done.
+
+e.g.
+
+	n == 2:  foo/bar/baz/foobar/quux => baz/foobar/quux
+	n == -2: foo/bar/baz/foobar/quux => foo/bar/baz
+*/
+func Strip(p string, abs, strict bool, n int) (slicedPath string) {
+
+	var pLen int
+	var absN int
+	var segments []string
+
+	segments = Segment(p, abs, strict)
+	pLen = len(segments)
+
+	absN = int(math.Abs(float64(n)))
+
+	if n == 0 || absN >= pLen {
+		slicedPath = p
+		return
+	}
+	if n > 0 {
+		segments = segments[n:]
+	} else {
+		segments = segments[:pLen-absN]
+	}
+
+	slicedPath = path.Join(segments...)
+
+	return
+}
+
+// StripSys is exactly like Strip but using (path/filepath).Join and SegmentSys.
+func StripSys(p string, abs, strict bool, n int) (slicedPath string) {
+
+	var pLen int
+	var absN int
+	var segments []string
+
+	segments = SegmentSys(p, abs, strict)
+	pLen = len(segments)
+
+	absN = int(math.Abs(float64(n)))
+
+	if n == 0 || absN >= pLen {
+		slicedPath = p
+		return
+	}
+	if n > 0 {
+		segments = segments[n:]
+	} else {
+		segments = segments[:pLen-absN]
+	}
+
+	slicedPath = filepath.Join(segments...)
+
+	return
+}
+
 /*
 filterTimes checks a times.Timespec of a file using:
   - an age specified by the caller