Commit 547e520359

Jakub Konka <kubkon@jakubkonka.com>
2020-07-29 09:02:21
Split DeviceIoControl path into two fn call paths
As discussed in the previous commit, it would be better to avoid function pointers to syscalls and explicitly split the control path into two function calls instead. This commit addresses that for `std.os.windows.DeviceIoControl`.
master
1 parent b3b00ec
Changed files (1)
lib
std
os
windows.zig
lib/std/os/windows.zig
@@ -228,20 +228,43 @@ pub fn DeviceIoControl(
     out: ?[]u8,
 ) DeviceIoControlError!void {
     // Logic from: https://doxygen.reactos.org/d3/d74/deviceio_8c.html
-    const syscall = if ((ioControlCode >> 16) == FILE_DEVICE_FILE_SYSTEM) ntdll.NtFsControlFile else ntdll.NtDeviceIoControlFile;
+    const is_fsctl = (ioControlCode >> 16) == FILE_DEVICE_FILE_SYSTEM;
+
     var io: IO_STATUS_BLOCK = undefined;
-    const rc = syscall(
-        h,
-        null,
-        null,
-        null,
-        &io,
-        ioControlCode,
-        if (in) |i| i.ptr else null,
-        if (in) |i| @intCast(ULONG, i.len) else 0,
-        if (out) |o| o.ptr else null,
-        if (out) |o| @intCast(ULONG, o.len) else 0,
-    );
+    const in_ptr = if (in) |i| i.ptr else null;
+    const in_len = if (in) |i| @intCast(ULONG, i.len) else 0;
+    const out_ptr = if (out) |o| o.ptr else null;
+    const out_len = if (out) |o| @intCast(ULONG, o.len) else 0;
+
+    const rc = blk: {
+        if (is_fsctl) {
+            break :blk ntdll.NtFsControlFile(
+                h,
+                null,
+                null,
+                null,
+                &io,
+                ioControlCode,
+                in_ptr,
+                in_len,
+                out_ptr,
+                out_len,
+            );
+        } else {
+            break :blk ntdll.NtDeviceIoControlFile(
+                h,
+                null,
+                null,
+                null,
+                &io,
+                ioControlCode,
+                in_ptr,
+                in_len,
+                out_ptr,
+                out_len,
+            );
+        }
+    };
     switch (rc) {
         .SUCCESS => {},
         .INVALID_PARAMETER => unreachable,