set_modtime more robust

Author: scivision

+stdlib/+java/set_modtime.m

@@ -8,6 +8,11 @@
 
 utc = convertTo(datetime(t, 'TimeZone', "UTC"), "posixtime");
 
-ok = java.io.File(file).setLastModified(int64(utc) * 1000);
+try
+  ok = java.io.File(file).setLastModified(int64(utc) * 1000);
+catch e
+  javaException(e)
+  ok = logical.empty;
+end
 
 end

+stdlib/+python/set_modtime.m

@@ -4,8 +4,10 @@
   dt (1,1) datetime
 end
 
-ok = false;
-if ~isfile(file), return, end
+if ~isfile(file)
+  ok = false;
+  return
+end
 
 utc = convertTo(datetime(dt, 'TimeZone', "UTC"), "posixtime");
 
@@ -14,8 +16,7 @@
   py.os.utime(file, py.tuple([s.st_atime, utc]));
   ok = true;
 catch e
-  warning(e.identifier, "set_modtime(%s, %s) failed: %s", file, utc, e.message);
-  ok = false;
+  ok = logical.empty;
 end
 
 end

+stdlib/set_modtime.m

@@ -5,18 +5,34 @@
 % * t: new modification time
 % * backend: backend to use
 %%% Outputs
-% * ok: true if successful
+% * i: true if successful
 % * b: backend used
 
-function [ok, b] = set_modtime(file, t, backend)
+function [i, b] = set_modtime(file, t, backend)
 arguments
   file
   t (1,1) datetime
   backend (1,:) string = ["java", "python", "sys"]
 end
 
-o = stdlib.Backend(mfilename(), backend);
-ok = o.func(file, t);
-b = o.backend;
+i = logical.empty;
+
+for b = backend
+  switch b
+    case "java"
+      i = stdlib.java.set_modtime(file, t);
+    case "python"
+      if stdlib.matlabOlderThan('R2022a'), continue, end
+      i = stdlib.python.set_modtime(file, t);
+    case "sys"
+      i = stdlib.sys.set_modtime(file, t);
+    otherwise
+      error("stdlib:set_modtime:ValueError", "Unknown backend: %s", b)
+  end
+
+  if ~isempty(i)
+    return
+  end
+end
 
 end