scroll_derive: support reference, closes #83 (#101)

m4b · Aug 26, 2024 · a7db2f2 · a7db2f2
1 parent 3cffc5a
commit a7db2f2
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Showing 3 changed files with 47 additions and 12 deletions.
diff --git a/scroll_derive/Cargo.toml b/scroll_derive/Cargo.toml
@@ -20,5 +20,5 @@ quote = "1"
 syn = "2"
 
 [dev-dependencies.scroll]
-version = "0.11"
+version = "0.12"
 path = ".."
diff --git a/scroll_derive/src/lib.rs b/scroll_derive/src/lib.rs
@@ -128,6 +128,14 @@ fn impl_pwrite_field(ident: &proc_macro2::TokenStream, ty: &syn::Type) -> proc_m
             _ => panic!("Pwrite derive with bad array constexpr"),
         },
         syn::Type::Group(group) => impl_pwrite_field(ident, &group.elem),
+        syn::Type::Reference(reference) => match *reference.elem {
+            syn::Type::Slice(_) => quote! {
+                dst.gwrite_with(self.#ident, offset, ())?
+            },
+            _ => quote! {
+                dst.gwrite_with(self.#ident, offset, ctx)?
+            },
+        },
         _ => {
             quote! {
                 dst.gwrite_with(&self.#ident, offset, ctx)?
@@ -166,32 +174,38 @@ fn impl_try_into_ctx(
     });
     let gn = quote! { #gl #( #gn ),* #gg };
     let gwref = if !gp.is_empty() {
-        let gi = gp.iter().map(|param: &syn::GenericParam| match param {
+        let gi: Vec<_> = gp.iter().filter_map(|param: &syn::GenericParam| match param {
             syn::GenericParam::Type(ref t) => {
                 let ident = &t.ident;
-                quote! {
+                Some(quote! {
                     &'a #ident : ::scroll::ctx::TryIntoCtx<::scroll::Endian>,
                     ::scroll::Error: ::std::convert::From<<&'a #ident as ::scroll::ctx::TryIntoCtx<::scroll::Endian>>::Error>,
                     <&'a #ident as ::scroll::ctx::TryIntoCtx<::scroll::Endian>>::Error: ::std::convert::From<scroll::Error>
-                }
+                })
             },
-            p => quote! { #p }
-        });
-        quote! { where #( #gi ),* }
+            syn::GenericParam::Lifetime(_) => None,
+            p => Some(quote! { #p }),
+        }).collect();
+        if !gi.is_empty() {
+            quote! { where #( #gi ),* }
+        } else {
+            quote! {}
+        }
     } else {
         quote! {}
     };
     let gw = if !gp.is_empty() {
-        let gi = gp.iter().map(|param: &syn::GenericParam| match param {
+        let gi = gp.iter().filter_map(|param: &syn::GenericParam| match param {
             syn::GenericParam::Type(ref t) => {
                 let ident = &t.ident;
-                quote! {
+                Some(quote! {
                     #ident : ::scroll::ctx::TryIntoCtx<::scroll::Endian>,
                     ::scroll::Error: ::std::convert::From<<#ident as ::scroll::ctx::TryIntoCtx<::scroll::Endian>>::Error>,
                     <#ident as ::scroll::ctx::TryIntoCtx<::scroll::Endian>>::Error: ::std::convert::From<scroll::Error>
-                }
+                })
             },
-            p => quote! { #p }
+            syn::GenericParam::Lifetime(_) => None,
+            p => Some(quote! { #p }),
         });
         quote! { where Self: ::std::marker::Copy, #( #gi ),* }
     } else {
@@ -205,7 +219,7 @@ fn impl_try_into_ctx(
             fn try_into_ctx(self, dst: &mut [u8], ctx: ::scroll::Endian) -> ::scroll::export::result::Result<usize, Self::Error> {
                 use ::scroll::Pwrite;
                 let offset = &mut 0;
-                #(#items;)*;
+                #(#items;)*
                 Ok(*offset)
             }
         }

diff --git a/scroll_derive/tests/tests.rs b/scroll_derive/tests/tests.rs
@@ -211,3 +211,24 @@ fn test_newtype() {
     let written = bytes.pwrite_with(&data, 0, LE).unwrap();
     assert_eq!(written, size);
 }
+
+#[derive(Debug, PartialEq, Eq, Pread, Pwrite, IOread, IOwrite, SizeWith)]
+struct Data10I(u8, u16);
+
+#[derive(Debug, Pwrite)]
+struct Data10<'b> {
+    pub inner: &'b Data10I,
+    pub name: &'b [u8],
+}
+
+#[test]
+fn test_reference() {
+    let inner = Data10I(255, 1);
+    let data = Data10 {
+        inner: &inner,
+        name: b"name",
+    };
+    let mut bytes = vec![0; 32];
+    assert_eq!(bytes.pwrite_with(&data, 0, LE).unwrap(), 7);
+    assert_eq!(bytes[..7], *b"\xff\x01\x00name");
+}