Build the local store on Windows

Fixes #10558

Co-Authored-By: Eugene Butler <eugene@eugene4.com>
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>

src/libutil/file-system.cc

@@ -94,7 +94,7 @@ Path canonPath(PathView path, bool resolveSymlinks)
         path,
         [&followCount, &temp, maxFollow, resolveSymlinks]
         (std::string & result, std::string_view & remaining) {
-            if (resolveSymlinks && std::filesystem::is_symlink(result)) {
+            if (resolveSymlinks && fs::is_symlink(result)) {
                 if (++followCount >= maxFollow)
                     throw Error("infinite symlink recursion in path '%0%'", remaining);
                 remaining = (temp = concatStrings(readLink(result), remaining));

src/libutil/file-system.hh

@@ -117,6 +117,11 @@ bool pathAccessible(const Path & path);
  */
 Path readLink(const Path & path);
 
+/**
+ * Open a `Descriptor` with read-only access to the given directory.
+ */
+Descriptor openDirectory(const std::filesystem::path & path);
+
 /**
  * Read the contents of a directory.  The entries `.` and `..` are
  * removed.

src/libutil/unix-domain-socket.hh

@@ -39,6 +39,7 @@ using Socket =
  * Windows gives this a different name
  */
 #  define SHUT_WR SD_SEND
+#  define SHUT_RDWR SD_BOTH
 #endif
 
 /**

src/libutil/unix/file-system.cc

@@ -0,0 +1,10 @@
+#include "file-system.hh"
+
+namespace nix {
+
+Descriptor openDirectory(const std::filesystem::path & path)
+{
+    return open(path.c_str(), O_RDONLY | O_DIRECTORY);
+}
+
+}

src/libutil/windows/file-system.cc

@@ -0,0 +1,12 @@
+#include "file-system.hh"
+
+namespace nix {
+
+Descriptor openDirectory(const std::filesystem::path & path)
+{
+    return CreateFileW(
+        path.c_str(), GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING,
+        FILE_FLAG_BACKUP_SEMANTICS, NULL);
+}
+
+}