1 files changed, 46 insertions, 0 deletions
diff --git a/devices/src/virtio/video/macros.rs b/devices/src/virtio/video/macros.rs
new file mode 100644
index 0000000..d1ed386
--- /dev/null
+++ b/devices/src/virtio/video/macros.rs
@@ -0,0 +1,46 @@
+// Copyright 2020 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//! Macros that helps virtio video implementation.
+
+/// Implements TryFrom<data_model::Le32> for an enum that implements `enumn::N`.
+#[macro_export]
+macro_rules! impl_try_from_le32_for_enumn {
+    ($ty:ty, $name:literal) => {
+        impl TryFrom<Le32> for $ty {
+            type Error = ReadCmdError;
+
+            fn try_from(x: Le32) -> Result<Self, Self::Error> {
+                let v: u32 = x.into();
+                Self::n(v).ok_or_else(|| {
+                    error!(concat!("invalid ", $name, ": {}"), v);
+                    ReadCmdError::InvalidArgument
+                })
+            }
+        }
+    };
+}
+
+/// Implements `From` between two structs whose each field implements `From` each other.
+#[macro_export]
+macro_rules! impl_from_for_interconvertible_structs {
+    ($t1:ident, $t2:ident, $($v:ident),+) => {
+        impl_from_for_interconvertible_structs_core!($t1, $t2, $( $v ),+ );
+        impl_from_for_interconvertible_structs_core!($t2, $t1, $( $v ),+ );
+    };
+}
+
+macro_rules! impl_from_for_interconvertible_structs_core {
+    ($t1:ident, $t2:ident, $($v:ident),+) => {
+        impl From<$t1> for $t2 {
+            #[allow(clippy::needless_update)]
+            fn from(x :$t1) -> Self {
+                $t2 {
+                    $( $v: x.$v.into(), )+
+                    ..Default::default() // for paddings
+                }
+            }
+        }
+    };
+}