1 files changed, 22 insertions, 19 deletions

diff --git a/src/pkg/path/filepath/path.go b/src/pkg/path/filepath/path.go
index 414df7d208..64cef291e6 100644
--- a/src/pkg/path/filepath/path.go
+++ b/src/pkg/path/filepath/path.go
@@ -13,8 +13,6 @@ import (
 	"strings"
 )
 
-// BUG(niemeyer): Package filepath does not yet work on Windows.
-
 // Clean returns the shortest path name equivalent to path
 // by purely lexical processing.  It applies the following rules
 // iteratively until no further processing can be done:
@@ -38,36 +36,39 @@ func Clean(path string) string {
 		return "."
 	}
 
-	rooted := path[0] == Separator
-	n := len(path)
+	rooted := IsAbs(path)
 
 	// 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.
+	prefix := volumeName(path)
+	path = path[len(prefix):]
+	n := len(path)
 	buf := []byte(path)
 	r, w, dotdot := 0, 0, 0
 	if rooted {
+		buf[0] = Separator
 		r, w, dotdot = 1, 1, 1
 	}
 
 	for r < n {
 		switch {
-		case path[r] == Separator:
+		case isSeparator(path[r]):
 			// empty path element
 			r++
-		case path[r] == '.' && (r+1 == n || path[r+1] == Separator):
+		case path[r] == '.' && (r+1 == n || isSeparator(path[r+1])):
 			// . element
 			r++
-		case path[r] == '.' && path[r+1] == '.' && (r+2 == n || path[r+2] == Separator):
+		case path[r] == '.' && path[r+1] == '.' && (r+2 == n || isSeparator(path[r+2])):
 			// .. element: remove to last separator
 			r += 2
 			switch {
 			case w > dotdot:
 				// can backtrack
 				w--
-				for w > dotdot && buf[w] != Separator {
+				for w > dotdot && !isSeparator(buf[w]) {
 					w--
 				}
 			case !rooted:
@@ -90,7 +91,7 @@ func Clean(path string) string {
 				w++
 			}
 			// copy element
-			for ; r < n && path[r] != Separator; r++ {
+			for ; r < n && !isSeparator(path[r]); r++ {
 				buf[w] = path[r]
 				w++
 			}
@@ -103,7 +104,7 @@ func Clean(path string) string {
 		w++
 	}
 
-	return string(buf[0:w])
+	return prefix + string(buf[0:w])
 }
 
 // ToSlash returns the result of replacing each separator character
@@ -137,7 +138,10 @@ func SplitList(path string) []string {
 // If there are no separators in path, Split returns an empty base
 // and file set to path.
 func Split(path string) (dir, file string) {
-	i := strings.LastIndex(path, string(Separator))
+	i := len(path) - 1
+	for i >= 0 && !isSeparator(path[i]) {
+		i--
+	}
 	return path[:i+1], path[i+1:]
 }
 
@@ -157,7 +161,7 @@ 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 && path[i] != Separator; i-- {
+	for i := len(path) - 1; i >= 0 && !isSeparator(path[i]); i-- {
 		if path[i] == '.' {
 			return path[i:]
 		}
@@ -250,11 +254,15 @@ func Base(path string) string {
 		return "."
 	}
 	// Strip trailing slashes.
-	for len(path) > 0 && path[len(path)-1] == Separator {
+	for len(path) > 0 && isSeparator(path[len(path)-1]) {
 		path = path[0 : len(path)-1]
 	}
 	// Find the last element
-	if i := strings.LastIndex(path, string(Separator)); i >= 0 {
+	i := len(path) - 1
+	for i >= 0 && !isSeparator(path[i]) {
+		i--
+	}
+	if i >= 0 {
 		path = path[i+1:]
 	}
 	// If empty now, it had only slashes.
@@ -263,8 +271,3 @@ func Base(path string) string {
 	}
 	return path
 }
-
-// IsAbs returns true if the path is absolute.
-func IsAbs(path string) bool {
-	return len(path) > 0 && path[0] == Separator
-}