url.lua: separate remove_dot_components() from absolute_path(); also use in _M.absolute() even when not merging

src/url.lua

@@ -76,6 +76,28 @@ function _M.unescape(s)
     end))
 end
 
+-----------------------------------------------------------------------------
+-- Removes '..' and '.' components appropriately from a path.
+-- Input
+--   path
+-- Returns
+--   dot-normalized path
+local function remove_dot_components(path)
+    repeat
+        local was = path
+        path = path:gsub('/%./', '/')
+    until path == was
+    repeat
+        local was = path
+        path = path:gsub('[^/]+/%.%./([^/]+)', '%1')
+    until path == was
+    path = path:gsub('[^/]+/%.%./*$', '')
+    path = path:gsub('/%.%.$', '/')
+    path = path:gsub('/%.$', '/')
+    path = path:gsub('^/%.%.', '')
+    return path
+end
+
 -----------------------------------------------------------------------------
 -- Builds a path from a base path and a relative path
 -- Input
@@ -85,21 +107,11 @@ end
 --   corresponding absolute path
 -----------------------------------------------------------------------------
 local function absolute_path(base_path, relative_path)
-    if string.sub(relative_path, 1, 1) == "/" then return relative_path end
-    local path = string.gsub(base_path, "[^/]*$", "")
-    path = path .. relative_path
-    repeat
-      local was = path
-      path = path:gsub('/%./', '/')
-    until path == was
-    repeat
-      local was = path
-      path = path:gsub('[^/]+/%.%./([^/]+)', '%1')
-    until path == was
-    path = path:gsub('[^/]+/%.%./*$', '')
-    path = path:gsub('/%.%.$', '/')
-    path = path:gsub('/%.$', '/')
-    path = path:gsub('^/%.%.', '')
+    if string.sub(relative_path, 1, 1) == "/" then
+      return remove_dot_components(relative_path) end
+    base_path = base_path:gsub("[^/]*$", "")
+    local path = base_path .. relative_path
+    path = remove_dot_components(path)
     return path
 end
 
@@ -225,10 +237,14 @@ function _M.absolute(base_url, relative_url)
     else
         base_parsed = _M.parse(base_url)
     end
+    local result
     local relative_parsed = _M.parse(relative_url)
-    if not base_parsed then return relative_url
-    elseif not relative_parsed then return base_url
-    elseif relative_parsed.scheme then return relative_url
+    if not base_parsed then
+        result = relative_url
+    elseif not relative_parsed then
+        result = base_url
+    elseif relative_parsed.scheme then
+        result = relative_url
     else
         relative_parsed.scheme = base_parsed.scheme
         if not relative_parsed.authority then
@@ -246,8 +262,9 @@ function _M.absolute(base_url, relative_url)
                     relative_parsed.path)
             end
         end
-        return _M.build(relative_parsed)
+        result = _M.build(relative_parsed)
     end
+    return remove_dot_components(result)
 end
 
 -----------------------------------------------------------------------------