parent: efficiency

simplify

parent: native only

The overhead and complication of multiple backends was not worth the
possible 10% speedup in Python

Author: scivision

+stdlib/+java/parent.m

@@ -5,7 +5,7 @@
 if ~strlength(file), return, end
 
 try %#ok<TRYNC>
-  n = string(py.str(py.pathlib.Path(file).owner()));
+  n = string(py.pathlib.Path(file).owner());
 end
 
 end

+stdlib/+native/parent.m

@@ -3,6 +3,5 @@
 try
   y = py.pathlib.Path(p).is_char_device();
 catch e
-  warning(e.identifier, "Python is_char_device failed: %s", e.message);
-  y = false;
+  y = logical.empty;
 end

+stdlib/+python/get_owner.m

@@ -1,4 +1,7 @@
 function y = is_exe(p)
+arguments
+  p (1,1) string
+end
 
 y = isfile(p);
 

+stdlib/+python/is_char_device.m

@@ -3,8 +3,7 @@
 try
   y = py.pathlib.Path(p).is_symlink();
 catch e
-  warning(e.identifier, "Python is_symlink failed: %s", e.message);
-  y = false;
+  y = logical.empty;
 end
 
 end

+stdlib/+python/is_exe.m

@@ -2,26 +2,26 @@
 %
 %% Inputs
 % * file: path to file or folder
-% * backend: backend to use
 %% Outputs
 % * par: parent directory of path
-% * b: backend used
 %% Examples:
 % stdlib.parent("a/b/c") == "a/b"
 % stdlib.parent("a/b/c/") == "a/b"
 
-function [par, b] = parent(file, backend)
+function p = parent(file)
 arguments
   file string
-  backend (1,:) string = ["java", "python", "native"]
 end
 
-if isscalar(file)
-  [fun, b] = hbackend(backend, "parent");
-  par = fun(file);
-else
-  b = "native";
-  par = stdlib.native.parent(file);
+p = fileparts(stdlib.drop_slash(file));
+
+i = ~strlength(p);
+p(i) = ".";
+
+% the ~all(i) is for Windows Matlab < R2025a
+if ispc() && ~all(i)
+  i = p(~i) == stdlib.root_name(file(~i));
+  p(i) = p(i) + "/";
 end
 
 end

+stdlib/+python/is_symlink.m

@@ -0,0 +1,19 @@
+function par = parent(pth)
+arguments
+  pth (1,1) string
+end
+
+par = java.io.File(pth).getParent();
+if isempty(par)
+  par = ".";
+  if ispc()
+    rn = stdlib.root_name(pth);
+    if strlength(pth) && strlength(rn) && startsWith(pth, rn)
+      par = strcat(rn, filesep);
+    end
+  end
+else
+  par = string(par);
+end
+
+end

+stdlib/+python/parent.m

@@ -0,0 +1,17 @@
+function par = parent(pth)
+arguments
+  pth (1,1) string
+end
+
+try
+  op = py.pathlib.Path(pth);
+  p = op.parent;
+  par = string(py.str(p));  % 2x faster than string(op.parents(1))
+  if ispc() && p == op.drive
+    par = par + filesep;
+  end
+catch e
+  par = "";
+end
+
+end