improve pathBuilder commenting, reduce repeated code

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

core/path.go

@@ -263,7 +263,8 @@ func sanitizePath(raw string) string {
 
 			// If next char is '.'
 			if raw[index] == '.' {
-				// Hit end of the path, break-out
+				// Hit end of the path on a '..',
+				// backtrack and break-out
 				if index+1 == length {
 					pb.backtrack()
 					break
@@ -273,7 +274,8 @@ func sanitizePath(raw string) string {
 				index++
 
 				// If next char is '/' then this is a
-				// back-track segment.
+				// backtrack segment, backtrack and skip
+				// to next
 				if raw[index] == '/' {
 					pb.backtrack()
 					continue
@@ -282,29 +284,21 @@ func sanitizePath(raw string) string {
 				// Split for next segment
 				pb.split()
 
-				// Else, add a '.'
+				// '..' but no backtrack, add to path
+				// (next '.' is added below)
 				pb.append('.')
 			} else {
 				// Split for next segment
 				pb.split()
 			}
 
-			// Else, append a '.'
+			// '.' but no backtrack, add to path
 			pb.append('.')
-
-			// Continue adding up to next '/'
-			for ; index < length && raw[index] != '/'; index++ {
-				pb.append(raw[index])
-			}
-
-			// Final iter to skip past the final '/'
-			index++
-			continue
+		} else {
+			// Split for next segment
+			pb.split()
 		}
 
-		// Split for next segment
-		pb.split()
-
 		// Iter through and add up to next '/'
 		for ; index < length && raw[index] != '/'; index++ {
 			pb.append(raw[index])