Windows: better handle leading double slash, possible UNC

Author: scivision

+stdlib/canonical.m

@@ -27,7 +27,7 @@
   c = p;
 end
 
-if ispc && strncmp(c, "\\", 2)
+if ispc && (startsWith(c, "\\") || startsWith(c, "//"))
   % UNC path is not canonicalized
   return
 end

+stdlib/drop_slash.m

@@ -1,4 +1,6 @@
 %% DROP_SLASH drop repeated and trailing slash
+%
+% on Windows, if leading double slash, do not drop
 
 function d = drop_slash(p)
 arguments
@@ -7,12 +9,17 @@
 
 s = stdlib.posix(p);
 
+uncslash = ispc && startsWith(s, "//");
+
 % drop repeated slashes inside string
 d = regexprep(s, "/+", "/");
 
 L = stdlib.len(d);
 
-if strcmp(d, '/') || ~L
+if L < 2
+  if uncslash
+    d = "//";
+  end
   return;
 end
 
@@ -26,10 +33,13 @@
   end
 end
 
+if uncslash
+  d = strcat("/", d);
+end
+
 end
 
 %!assert(drop_slash(''), '')
 %!assert(drop_slash('/'), '/')
-%!assert(drop_slash('//'), '/')
 %!assert(drop_slash('a//b'), 'a/b')
 %!assert(drop_slash('a//b/'), 'a/b')

+stdlib/expanduser.m

@@ -16,7 +16,7 @@
 e = stdlib.drop_slash(p);
 
 L = stdlib.len(e);
-if ~L || ~strncmp(e, "~", 1) || (L > 1 && ~strncmp(e, "~/", 2))
+if ~L || ~startsWith(e, "~") || (L > 1 && ~startsWith(e, "~/"))
   return
 end
 

+stdlib/is_rosetta.m

@@ -11,7 +11,7 @@
 % uname -m reports "x86_64" from within Matlab on Apple Silicon if using Rosetta
 
 [ret, raw] = system("sysctl -n sysctl.proc_translated");
-r = ret == 0 && strncmp(raw, '1', 1);
+r = ret == 0 && startsWith(raw, '1');
 
 end
 

+stdlib/normalize.m

@@ -14,14 +14,15 @@
   use_java (1,1) logical = false
 end
 
-
 if use_java
   o = javaFileObject(p).toPath().normalize();
-  n = jPosix(o);
+  n = stdlib.drop_slash(jPosix(o));
 else
 
   n = stdlib.posix(p);
 
+  uncslash = ispc && startsWith(n, "//");
+
   % use split to remove /../ and /./ and duplicated /
   parts = split(n, '/');
   i0 = 1;
@@ -59,6 +60,10 @@
     end
   end
 
+  if uncslash
+    n = strcat("/", n);
+  end
+
 end
 
 

test/TestNormalize.m

@@ -2,7 +2,11 @@
 
 properties (TestParameter)
 use_java = num2cell(unique([stdlib.has_java(), false]))
+p
+end
 
+methods (TestParameterDefinition, Static)
+function p = init()
 p = {
   {"", "."}, ...
   {"a/..", "."}, ...
@@ -22,6 +26,12 @@
   {"./a/.", "a"}, ...
   {"../a", "../a"}
 };
+
+if ispc
+  p{3}{2} = "//a/b";
+end
+
+end
 end
 
 methods (Test)