is_symlink: prefer native as it's 4x faster

read_symlink: prefer native

create_symlink: faster native

Author: scivision

+stdlib/+native/create_symlink.m

@@ -105,14 +105,6 @@
     case 'native'
 
       switch functionName
-        case 'create_symlink'
-          % Some Windows R2025a give error 'MATLAB:io:filesystem:symlink:NeedsAdminPerms'
-          % 25.1.0.2973910 (R2025a) Update 1 gave this error for example.
-          if stdlib.matlabOlderThan('R2024b') || ispc()
-            continue
-          end
-        case {'is_symlink', 'read_symlink'}
-          if stdlib.matlabOlderThan('R2024b'), continue, end
         case {'get_permissions', 'set_permissions'}
           if stdlib.matlabOlderThan('R2025a'), continue, end
       end

+stdlib/+native/is_symlink.m

@@ -6,6 +6,9 @@
 %%% Outputs
 % * ok: true if successful
 % * b: backend used
+%
+% Some Windows Matlab R2025a give error 'MATLAB:io:filesystem:symlink:NeedsAdminPerms'
+% For example, Matlab 25.1.0.2973910 R2025a Update 1 gave this error.
 
 function [ok, b] = create_symlink(target, link, backend)
 arguments
@@ -14,8 +17,30 @@
   backend (1,:) string = ["native", "dotnet", "python", "sys"]
 end
 
+
+if ismember('native', backend) || stdlib.strempty(backend)
+  try
+    createSymbolicLink(link, target);
+    ok = true;
+    b = "native";
+    return
+  catch e
+    switch e.identifier
+      case {'MATLAB:UndefinedFunction', 'MATLAB:io:filesystem:symlink:NeedsAdminPerms'}
+        % pass through to stdlib.Backend
+      case {'MATLAB:io:filesystem:symlink:FileExists', 'MATLAB:io:filesystem:symlink:TargetNotFound'}
+        ok = false;
+        return
+      otherwise
+        rethrow(e)
+    end
+  end
+
+  backend(ismember(backend, 'native')) = [];
+end
+
 o = stdlib.Backend(mfilename(), backend);
+b = o.backend;
 ok = o.func(target, link);
 
-b = o.backend;
 end

+stdlib/+native/read_symlink.m

@@ -13,14 +13,22 @@
   backend (1,:) string = ["native", "java", "python", "dotnet", "sys"]
 end
 
-o = stdlib.Backend(mfilename(), backend);
+if ismember('native', backend) || stdlib.strempty(backend)
+  try
+    ok = isSymbolicLink(file);
+    b = "native";
+    return
+  catch e
+    if e.identifier ~= "MATLAB:UndefinedFunction"
+      rethrow(e)
+    end
+  end
 
-if isscalar(file)
-  ok = o.func(file);
-else
-  ok = arrayfun(o.func, file);
+  backend(ismember(backend, 'native')) = [];
 end
 
+o = stdlib.Backend(mfilename(), backend);
 b = o.backend;
+ok = o.func(file);
 
 end

+stdlib/Backend.m

@@ -16,15 +16,24 @@
   backend (1,:) string = ["native", "java", "dotnet", "python", "sys"]
 end
 
-o = stdlib.Backend(mfilename(), backend);
 
-if isscalar(file)
-  r = o.func(file);
-else
-  r = arrayfun(o.func, file);
+if ismember('native', backend) || stdlib.strempty(backend)
+  try
+    [ok, r] = isSymbolicLink(file);
+    r(~ok) = "";
+    b = "native";
+    return
+  catch e
+    if e.identifier ~= "MATLAB:UndefinedFunction"
+      rethrow(e)
+    end
+  end
+
+  backend(ismember(backend, 'native')) = [];
 end
 
+o = stdlib.Backend(mfilename(), backend);
 b = o.backend;
-
+r = o.func(file);
 
 end

+stdlib/create_symlink.m

@@ -15,6 +15,6 @@
 
 function result = run_bench(name)
 suite = testsuite(name);
-exp = matlab.perftest.TimeExperiment.limitingSamplingError(MaxSamples=20, RelativeMarginOfError=0.1);
+exp = matlab.perftest.TimeExperiment.limitingSamplingError(MaxSamples=50, RelativeMarginOfError=0.1);
 result = exp.run(suite);
 end

+stdlib/is_symlink.m

@@ -14,8 +14,8 @@
 
 methods (TestParameterDefinition, Static)
 function [is_backend, rs_backend] = setupBackend()
-  is_backend = init_backend('is_symlink');
-  rs_backend = init_backend('read_symlink');
+  is_backend = cellstr(["native", init_backend('is_symlink')]);
+  rs_backend = cellstr(["native", init_backend('read_symlink')]);
 end
 end
 

+stdlib/read_symlink.m

@@ -20,9 +20,9 @@
 
 methods (TestParameterDefinition, Static)
 function [B_create_symlink, B_read_symlink, B_is_symlink] = setupBackends()
-B_create_symlink = init_backend("create_symlink");
-B_read_symlink = init_backend("read_symlink");
-B_is_symlink = init_backend("is_symlink");
+B_create_symlink = cellstr(["native", init_backend("create_symlink")]);
+B_read_symlink = cellstr(["native", init_backend("read_symlink")]);
+B_is_symlink = cellstr(["native", init_backend("is_symlink")]);
 end
 end
 
@@ -51,11 +51,6 @@ function test_is_symlink(tc, p, B_is_symlink)
 tc.verifyEqual(stdlib.is_symlink(p{1}, B_is_symlink), p{2}, p{1})
 end
 
-function test_is_symlink_array(tc, B_is_symlink)
-r = stdlib.is_symlink([tc.link, mfilename() + ".m"], B_is_symlink);
-tc.verifyEqual(r, [true, false], "failed to detect own link")
-end
-
 
 function test_read_symlink_empty(tc, Pre, B_read_symlink)
 tc.verifyEqual(stdlib.read_symlink(Pre, B_read_symlink), "")
@@ -69,14 +64,6 @@ function test_read_symlink(tc, B_read_symlink)
 end
 
 
-function test_read_symlink_array(tc, B_read_symlink)
-r = stdlib.read_symlink([tc.link, mfilename() + ".m"], B_read_symlink);
-exp = [tc.target, ""];
-tc.verifyClass(r, 'string')
-tc.verifyEqual(r, exp, "failed to detect own link")
-end
-
-
 function test_create_symlink(tc, B_create_symlink)
 tc.applyFixture(matlab.unittest.fixtures.SuppressedWarningsFixture(["MATLAB:io:filesystem:symlink:TargetNotFound","MATLAB:io:filesystem:symlink:FileExists"]))