1 files changed, 52 insertions, 0 deletions
diff --git a/buffered-reader/src/macros.rs b/buffered-reader/src/macros.rs
new file mode 100644
index 00000000..ff30d6fb
--- /dev/null
+++ b/buffered-reader/src/macros.rs
@@ -0,0 +1,52 @@
+/// A simple shortcut for ensuring a type is send and sync.
+///
+/// For most types just call it after defining the type:
+///
+/// ```
+/// pub struct MyStruct {}
+/// assert_send_and_sync!(MyStruct);
+/// ```
+///
+/// For types with lifetimes, use the anonymous lifetime:
+///
+/// ```
+/// pub struct WithLifetime<'a> {}
+/// assert_send_and_sync!(MyStruct<'_>);
+/// ```
+///
+/// For a type generic over another type `W`,
+/// pass the type `W` as a second argument
+/// including a trait bound when needed:
+///
+/// ```
+/// pub struct MyWriter<W: io::Write> {}
+/// assert_send_and_sync!(MyWriterStruct<W>, W: io::Write);
+/// ```
+///
+/// This will assert that `MyWriterStruct<W>` is `Send` and `Sync`
+/// if `W` is `Send` and `Sync`.
+///
+/// You can also combine the two and be generic over multiple types:
+///
+/// ```
+/// pub struct MyWriterWithLifetime<a', C, W: io::Write> {}
+/// assert_send_and_sync!(MyWriterStruct<'_, C, W>, C, W: io::Write);
+/// ```
+///
+macro_rules! assert_send_and_sync {
+    ( $x:ty where $( $g:ident$( : $b:path )? $(,)?)*) => {
+        impl<$( $g ),*> crate::macros::Sendable for $x
+            where $( $g: Send + Sync $(+ $b)? ),*
+            {}
+        impl<$( $g ),*> crate::macros::Syncable for $x
+            where $( $g: Send + Sync $(+ $b)? ),*
+            {}
+    };
+    ( $x:ty ) => {
+        impl crate::macros::Sendable for $x {}
+        impl crate::macros::Syncable for $x {}
+    };
+}
+
+pub(crate) trait Sendable : Send {}
+pub(crate) trait Syncable : Sync {}