is_writable: java much faster, with fallback

Author: scivision

+stdlib/+java/is_writable.m

@@ -0,0 +1,9 @@
+function y = is_writable(p)
+
+% https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/nio/file/Files.html#isWritable(java.nio.file.Path)
+% java.nio.file.Files java is about 10x slower than fileattrib and needs absolute()
+% file = stdlib.absolute(file, "", false);
+% ok = java.nio.file.Files.isWritable(javaPathObject(file));
+
+y = javaObject("java.io.File", p).canWrite();
+end

+stdlib/+native/is_writable.m

@@ -0,0 +1,22 @@
+function y = is_writable(p)
+
+y = false;
+
+if ~stdlib.exists(p), return, end
+
+if ~isMATLABReleaseOlderThan('R2025a')
+
+  props = "Writable";
+  if isunix
+    props = [props, "GroupWrite", "OtherWrite"];
+  end
+
+  t = getPermissions(filePermissions(p), props);
+  y = t.Writable;
+
+else
+  a = stdlib.native.file_attributes(p);
+  y = a.UserWrite || a.GroupWrite || a.OtherWrite;
+end
+
+end

+stdlib/is_writable.m

@@ -5,31 +5,15 @@
 %% Outputs
 % ok: logical array of the same size as p, true if file is writable
 
-function ok = is_writable(p)
+function y = is_writable(p)
 arguments
-  p string
+  p {mustBeTextScalar}
 end
 
-ok(size(p)) = false;
-
-i = stdlib.exists(p);
-
-if ~any(i), return, end
-
-if ~isMATLABReleaseOlderThan('R2025a')
-
-  props = "Writable";
-  if isunix
-    props = [props, "GroupWrite", "OtherWrite"];
-  end
-
-  t = getPermissions(filePermissions(p(i)), props);
-  ok(i) = any(t{:,:}, 2);
-
+if stdlib.has_java()
+  y = stdlib.java.is_writable(p);
 else
-  a = stdlib.native.file_attributes(p);
-  ok = a.UserWrite || a.GroupWrite || a.OtherWrite;
+  y = stdlib.native.is_writable(p);
 end
 
 end
-%!assert (is_writable('is_writable.m'))

+stdlib/xcode_version.m

@@ -8,6 +8,8 @@
   [s, m] = system('pkgutil --pkg-info com.apple.pkg.CLTools_Executables');
   if s == 0
     v = regexp(m, '(?<=version:\s*)(\d+\.\d+(\.\d+)+)', 'match', 'once');
+  else
+    warning("stdlib:xcode_version:runtimeError", "%d failed to get Command Line Tools Xcode version", s)
   end
 end
 

test/TestExists.m

@@ -9,6 +9,7 @@
 }
 % on CI matlabroot can be writable!
 isr_fun = {@stdlib.is_readable, @stdlib.java.is_readable, @stdlib.native.is_readable}
+isw_fun = {@stdlib.is_writable, @stdlib.java.is_writable, @stdlib.native.is_writable}
 end
 
 methods(TestClassSetup)
@@ -34,8 +35,10 @@ function test_is_readable(tc, Ps, isr_fun)
 end
 
 
-function test_is_writable(tc, Ps)
-ok = stdlib.is_writable(Ps{1});
+function test_is_writable(tc, Ps, isw_fun)
+is_capable(tc, isw_fun)
+
+ok = isw_fun(Ps{1});
 tc.verifyEqual(ok, Ps{2}, Ps{1})
 end