Function ntToWin32Namespace [src]

Similar to RtlNtPathNameToDosPathName but does not do any heap allocation. The possible transformations are: ??\C:\Some\Path -> C:\Some\Path ??\UNC\server\share\foo -> \server\share\foo If the path does not have the NT namespace prefix, then error.NotNtPath is returned. Functionality is based on the ReactOS test cases found here: https://github.com/reactos/reactos/blob/master/modules/rostests/apitests/ntdll/RtlNtPathNameToDosPathName.c path should be encoded as WTF-16LE.

Prototype

pub fn ntToWin32Namespace(path: []const u16) !PathSpace

Parameters

path: []const u16

Example

 test ntToWin32Namespace {
    const L = std.unicode.utf8ToUtf16LeStringLiteral;

    try testNtToWin32Namespace(L("UNC"), L("\\??\\UNC"));
    try testNtToWin32Namespace(L("\\\\"), L("\\??\\UNC\\"));
    try testNtToWin32Namespace(L("\\\\path1"), L("\\??\\UNC\\path1"));
    try testNtToWin32Namespace(L("\\\\path1\\path2"), L("\\??\\UNC\\path1\\path2"));

    try testNtToWin32Namespace(L(""), L("\\??\\"));
    try testNtToWin32Namespace(L("C:"), L("\\??\\C:"));
    try testNtToWin32Namespace(L("C:\\"), L("\\??\\C:\\"));
    try testNtToWin32Namespace(L("C:\\test"), L("\\??\\C:\\test"));
    try testNtToWin32Namespace(L("C:\\test\\"), L("\\??\\C:\\test\\"));

    try std.testing.expectError(error.NotNtPath, ntToWin32Namespace(L("foo")));
    try std.testing.expectError(error.NotNtPath, ntToWin32Namespace(L("C:\\test")));
    try std.testing.expectError(error.NotNtPath, ntToWin32Namespace(L("\\\\.\\test")));
}

Source

  pub fn ntToWin32Namespace(path: []const u16) !PathSpace {
    if (path.len > PATH_MAX_WIDE) return error.NameTooLong;

    var path_space: PathSpace = undefined;
    const namespace_prefix = getNamespacePrefix(u16, path);
    switch (namespace_prefix) {
        .nt => {
            var dest_index: usize = 0;
            var after_prefix = path[4..]; // after the `\??\`
            // The prefix \??\UNC\ means this is a UNC path, in which case the
            // `\??\UNC\` should be replaced by `\\` (two backslashes)
            // TODO: the "UNC" should technically be matched case-insensitively, but
            //       it's unlikely to matter since most/all paths passed into this
            //       function will have come from the OS meaning it should have
            //       the 'canonical' uppercase UNC.
            const is_unc = after_prefix.len >= 4 and
                std.mem.eql(u16, after_prefix[0..3], std.unicode.utf8ToUtf16LeStringLiteral("UNC")) and
                std.fs.path.PathType.windows.isSep(u16, std.mem.littleToNative(u16, after_prefix[3]));
            if (is_unc) {
                path_space.data[0] = comptime std.mem.nativeToLittle(u16, '\\');
                dest_index += 1;
                // We want to include the last `\` of `\??\UNC\`
                after_prefix = path[7..];
            }
            @memcpy(path_space.data[dest_index..][0..after_prefix.len], after_prefix);
            path_space.len = dest_index + after_prefix.len;
            path_space.data[path_space.len] = 0;
            return path_space;
        },
        else => return error.NotNtPath,
    }
}  