fix(serdey): use ByteBuf in alloc or std

Signed-off-by: becominginsane <francesco@zondax.ch>

Cargo.toml

@@ -74,6 +74,10 @@ version = "0.11.5"
 default-features = false
 optional = true
 
+[dependencies.cfg-if]
+version = "1.0.0"
+optional = true
+
 [dependencies.sha2]
 version = "0.9.3"
 default-features = false
@@ -107,13 +111,13 @@ harness = false
 default = ["std", "u64_backend", "getrandom"] # "rand"
 preaudit_deprecated = []
 nightly = ["curve25519-dalek/nightly", "rand/nightly"] # "zeroize/nightly"
-alloc = ["curve25519-dalek/alloc", "rand_core/alloc"]
-std = ["getrandom", "curve25519-dalek/std"] # "failure/std"
+alloc = ["curve25519-dalek/alloc", "rand_core/alloc", "serde_bytes/alloc"]
+std = ["getrandom", "curve25519-dalek/std", "serde_bytes/std"] # "failure/std"
 asm = ["sha2/asm"]
 u64_backend = ["curve25519-dalek/u64_backend"]
 u32_backend = ["curve25519-dalek/u32_backend"]
 avx2_backend = ["curve25519-dalek/avx2_backend"]
-serde = ["serde_crate", "serde_bytes"]
+serde = ["serde_crate", "serde_bytes", "cfg-if"]
 # We cannot make getrandom a direct dependency because rand_core makes
 # getrandom a feature name, which requires forwarding.
 getrandom = ["rand_core/getrandom"]

src/serdey.rs

@@ -30,7 +30,13 @@ impl ::serde_crate::Serialize for $t {
 
 impl<'d> ::serde_crate::Deserialize<'d> for $t {
  fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: ::serde_crate::Deserializer<'d> {
- let bytes = <&::serde_bytes::Bytes>::deserialize(deserializer)?;
+ cfg_if::cfg_if!{
+ if #[cfg(any(feature = "alloc", feature = "std"))] {
+ let bytes = <::serde_bytes::ByteBuf>::deserialize(deserializer)?;
+ } else {
+ let bytes = <&::serde_bytes::Bytes>::deserialize(deserializer)?;
+ }
+ }
 
  Self::from_bytes(bytes.as_ref())
  .map_err(crate::errors::serde_error_from_signature_error)