pread: remove Copy bound when generics are present, not needed; move test with generics and ctx dependent on prior fields to complex.rs file; add test showing decoding works

Author: m4b

scroll_derive/src/lib.rs

@@ -168,7 +168,7 @@ fn impl_struct(
             syn::GenericParam::Type(t) => Some({
                 let ident = &t.ident;
                 quote! {
-                    #ident : ::scroll::ctx::TryFromCtx<#lifetime, ::scroll::Endian, Error = ::scroll::Error> + ::std::marker::Copy,
+                    #ident : ::scroll::ctx::TryFromCtx<#lifetime, ::scroll::Endian, Error = ::scroll::Error>,
                     ::scroll::Error : ::std::convert::From<< #ident as ::scroll::ctx::TryFromCtx<#lifetime, ::scroll::Endian>>::Error>,
                     < #ident as ::scroll::ctx::TryFromCtx<#lifetime, ::scroll::Endian>>::Error : ::std::convert::From<scroll::Error>
                 }

scroll_derive/tests/complex.rs

@@ -0,0 +1,54 @@
+use scroll::Pread;
+use scroll_derive::{Pread, Pwrite};
+
+#[derive(Debug, Pread, Pwrite)]
+pub struct FloofHeader {
+    pub boop: u8,
+    pub length: u16,
+    pub flag: u8,
+    pub quux_service: u8,
+    pub quux_client_id: u8,
+}
+
+pub trait QuuxHeaderApi {
+    fn msg_len(&self) -> usize;
+}
+
+#[derive(Debug, Pread, Pwrite)]
+pub struct QuuxHeader {
+    pub typ: u8,
+    pub txn_id: u16,
+    pub msg_id: u16,
+    pub msg_len: u16,
+}
+
+impl QuuxHeaderApi for QuuxHeader {
+    fn msg_len(&self) -> usize {
+        self.msg_len as usize
+    }
+}
+
+#[derive(Debug, Pread, Pwrite)]
+pub struct Response<'a, T: QuuxHeaderApi> {
+    pub floof: FloofHeader,
+    pub quux: T,
+    #[scroll(ctx = quux.msg_len())]
+    pub tlvs: &'a [u8],
+}
+
+#[test]
+fn test_pread_generics_with_ctx_dependent_on_prior_field() {
+    let bytes = [
+        1, 70, 0, 128, 9, 3, 4, 1, 0, 46, 0, 58, 0, 1, 8, 0, 1, 1, 4, 0, 1, 6, 0, 0, 16, 16, 0, 1,
+        1, 0, 12, 43, 47, 52, 48, 49, 57, 42, 54, 49, 53, 50, 51, 39, 3, 0, 1, 1, 2, 43, 19, 0, 1,
+        1, 0, 0, 0, 1, 12, 41, 49, 51, 48, 49, 57, 42, 54, 43, 51, 50, 54,
+    ];
+    let resp: Response<QuuxHeader> = bytes.pread(0).unwrap();
+    assert_eq!(resp.floof.flag, 0x80);
+    assert_eq!(resp.floof.length as usize, bytes.len() - 1);
+    assert_eq!(resp.floof.quux_service, 0x9);
+    assert_eq!(resp.floof.quux_client_id, 3);
+    assert_eq!(resp.quux.msg_len(), resp.tlvs.len());
+    assert_eq!(resp.quux.typ, 0x4);
+    assert_eq!(resp.quux.txn_id, 1);
+}

scroll_derive/tests/tests.rs

@@ -302,38 +302,3 @@ fn test_pread_lifetime() {
     b2.pwrite(&data, 0).unwrap();
     assert_eq!(b2, bytes);
 }
-
-#[derive(Debug, Pread, Pwrite)]
-pub struct FloofHeader {
-    pub boop: u8,
-    pub length: u16,
-    pub flag: u8,
-    pub quux_service: u8,
-    pub quux_client_id: u8,
-}
-
-pub trait QuuxHeaderApi {
-    fn msg_len(&self) -> usize;
-}
-
-#[derive(Debug, Copy, Clone, Pread, Pwrite)]
-pub struct QuuxHeader {
-    pub typ: u8,
-    pub txn_id: u16,
-    pub msg_id: u16,
-    pub msg_len: u16,
-}
-
-impl QuuxHeaderApi for QuuxHeader {
-    fn msg_len(&self) -> usize {
-        self.msg_len as usize
-    }
-}
-
-#[derive(Debug, Pread, Pwrite)]
-pub struct Response<'a, T: QuuxHeaderApi> {
-    pub floof: FloofHeader,
-    pub quux: T,
-    #[scroll(ctx = quux.msg_len())]
-    pub tlvs: &'a [u8],
-}