exists: benchmark java.io.file vs java.nio.file

test:exists: add relative file case

Author: scivision

+stdlib/canonical.m

@@ -31,7 +31,7 @@
   return
 end
 
-e = stdlib.exists(c);
+e = stdlib.exists(c, use_java);
 
 if ~stdlib.is_absolute(c)
   if e

+stdlib/drop_slash.m

@@ -0,0 +1,21 @@
+%% DROP_SLASH drop repeated and trailing slash
+
+function d = drop_slash(p)
+arguments
+  p (1,1) string
+end
+
+s = stdlib.posix(p);
+
+% drop repeated slashes inside string
+d = regexprep(s, "/+", "/");
+
+if d == "/"
+  return;
+end
+
+if ~ispc || (strlength(d) ~= 3 || d ~= stdlib.root(s))
+  d = strip(d, "right", "/");
+end
+
+end

+stdlib/exists.m

@@ -5,7 +5,6 @@
 %%% Outputs
 % * ok: true if exists
 %
-% Ref: https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/io/File.html#exists()
 
 function ok = exists(p, use_java)
 arguments
@@ -14,9 +13,14 @@
 end
 
 if use_java
-% Java takes 2x to 10x as long as intrinsic way worst case
-% the intrinsic way above is at least not slower
 
+% https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/nio/file/Files.html#exists(java.nio.file.Path,java.nio.file.LinkOption...)
+% this takes 2x longer than java.io.File.exists()
+% opt = java.nio.file.LinkOption.values;
+% ok = java.nio.file.Files.exists(java.io.File(p).toPath(), opt);
+
+% https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/io/File.html#exists()
+% takes 2x longer than native Matlab isfile || isfolder
   ok = java.io.File(p).exists();
 else
   ok = isfile(p) || isfolder(p);

+stdlib/samepath.m

@@ -17,7 +17,7 @@
 end
 
 issame = false;
-if ~stdlib.exists(path1) || ~stdlib.exists(path2)
+if ~stdlib.exists(path1, use_java) || ~stdlib.exists(path2, use_java)
   return
 end
 

example/bench_exists.m

@@ -0,0 +1,15 @@
+%% benchmark for exists()
+
+f = mfilename("fullpath") + ".m";
+%f = tempname;
+
+fno = @() stdlib.exists(f, false);
+fjava = @() stdlib.exists(f, true);
+
+t_no = timeit(fno);
+t_java = timeit(fjava);
+
+disp("No Java: " + t_no + " s")
+disp("Java: " + t_java + " s")
+
+disp("Java is " + t_no/t_java + " times faster")

test/TestFileImpure.m

@@ -5,7 +5,7 @@
 end
 
 properties(TestParameter)
-p_exists = {{pwd(), true}, {mfilename("fullpath") + ".m", true}, {tempname, false}}
+p_exists = {{pwd(), true}, {mfilename("fullpath") + ".m", true}, {"TestFileImpure.m", true} {tempname, false}}
 % on CI matlabroot can be writable!
 in_is_write = {pwd(), "not-exists"};
 ref_is_write = {true, false}
@@ -35,18 +35,18 @@
 
 methods(TestClassSetup)
 
-function classSetup(tc, classToTest)
-constructor = str2func(classToTest);
-tc.tobj = constructor();
-end
-
 function setup_path(tc)
 import matlab.unittest.fixtures.PathFixture
 cwd = fileparts(mfilename("fullpath"));
 top = fullfile(cwd, "..");
 tc.applyFixture(PathFixture(top))
 end
 
+function classSetup(tc, classToTest)
+constructor = str2func(classToTest);
+tc.tobj = constructor();
+end
+
 end
 
 methods (Test, ParameterCombination = 'sequential')