os.nim: use the new pathnorm.normalizePath implementation

lib/pure/os.nim

@@ -984,36 +984,37 @@ proc normalizePath*(path: var string) {.rtl, extern: "nos$1", tags: [], noNimScr
   ##
   ## Warning: URL-encoded and Unicode attempts at directory traversal are not detected.
   ## Triple dot is not handled.
-  let isAbs = isAbsolute(path)
-  var stack: seq[string] = @[]
-  for p in split(path, {DirSep}):
-    case p
-    of "", ".":
-      continue
-    of "..":
-      if stack.len == 0:
-        if isAbs:
-          discard  # collapse all double dots on absoluta paths
-        else:
+  path = pathnorm.normalizePath(path)
+  when false:
+    let isAbs = isAbsolute(path)
+    var stack: seq[string] = @[]
+    for p in split(path, {DirSep}):
+      case p
+      of "", ".":
+        continue
+      of "..":
+        if stack.len == 0:
+          if isAbs:
+            discard  # collapse all double dots on absoluta paths
+          else:
+            stack.add(p)
+        elif stack[^1] == "..":
           stack.add(p)
-      elif stack[^1] == "..":
-        stack.add(p)
+        else:
+          discard stack.pop()
       else:
-        discard stack.pop()
-    else:
-      stack.add(p)
+        stack.add(p)
 
-  if isAbs:
-    path = DirSep & join(stack, $DirSep)
-  elif stack.len > 0:
-    path = join(stack, $DirSep)
-  else:
-    path = "."
+    if isAbs:
+      path = DirSep & join(stack, $DirSep)
+    elif stack.len > 0:
+      path = join(stack, $DirSep)
+    else:
+      path = "."
 
 proc normalizedPath*(path: string): string {.rtl, extern: "nos$1", tags: [], noNimScript.} =
   ## Returns a normalized path for the current OS. See `<#normalizePath>`_
-  result = path
-  normalizePath(result)
+  result = pathnorm.normalizePath(path)
 
 when defined(Windows) and not defined(nimscript):
   proc openHandle(path: string, followSymlink=true, writeAccess=false): Handle =

lib/pure/pathnorm.nim

@@ -66,19 +66,26 @@ proc addNormalizePath*(x: string; result: var string; state: var int; dirSep = D
     if (state shr 1 == 0) and isSlash(x, b):
       result.add dirSep
       state = state or 1
-    elif result.len > (state and 1) and isDotDot(x, b):
-      var d = result.len
-      # f/..
-      while (d-1) > (state and 1) and result[d-1] notin {DirSep, AltSep}:
-        dec d
-      if d > 0: setLen(result, d-1)
+    elif isDotDot(x, b):
+      if (state shr 1) >= 1:
+        var d = result.len
+        # f/..
+        while (d-1) > (state and 1) and result[d-1] notin {DirSep, AltSep}:
+          dec d
+        if d > 0:
+          setLen(result, d-1)
+          dec state, 2
+      else:
+        if result.len > 0 and result[^1] notin {DirSep, AltSep}:
+          result.add dirSep
+        result.add substr(x, b[0], b[1])
     elif isDot(x, b):
       discard "discard the dot"
     elif b[1] >= b[0]:
       if result.len > 0 and result[^1] notin {DirSep, AltSep}:
         result.add dirSep
       result.add substr(x, b[0], b[1])
-    inc state, 2
+      inc state, 2
 
 proc normalizePath*(path: string; dirSep = DirSep): string =
   ## Example: