Provide trait impl for types that can be used with serde_bytes

Author: dtolnay

src/de.rs

@@ -0,0 +1,105 @@
+use crate::Bytes;
+use serde::Deserializer;
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+use crate::ByteBuf;
+
+#[cfg(feature = "alloc")]
+use alloc::borrow::Cow;
+#[cfg(all(feature = "std", not(feature = "alloc")))]
+use std::borrow::Cow;
+
+#[cfg(feature = "alloc")]
+use alloc::boxed::Box;
+
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
+
+/// Types that can be deserialized via `#[serde(with = "serde_bytes")]`.
+pub trait Deserialize<'de>: Sized {
+    #[allow(missing_docs)]
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>;
+}
+
+impl<'de: 'a, 'a> Deserialize<'de> for &'a [u8] {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        // Via the serde::Deserialize impl for &[u8].
+        serde::Deserialize::deserialize(deserializer)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de> Deserialize<'de> for Vec<u8> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        Deserialize::deserialize(deserializer).map(ByteBuf::into_inner)
+    }
+}
+
+impl<'de: 'a, 'a> Deserialize<'de> for &'a Bytes {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        Deserialize::deserialize(deserializer).map(Bytes::new)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de> Deserialize<'de> for ByteBuf {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        // Via the serde::Deserialize impl for ByteBuf.
+        serde::Deserialize::deserialize(deserializer)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, [u8]> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        Deserialize::deserialize(deserializer).map(Cow::Borrowed)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de: 'a, 'a> Deserialize<'de> for Cow<'a, Bytes> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        Deserialize::deserialize(deserializer).map(Cow::Borrowed)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de> Deserialize<'de> for Box<[u8]> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        Deserialize::deserialize(deserializer).map(Vec::into_boxed_slice)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de> Deserialize<'de> for Box<Bytes> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let bytes: Box<[u8]> = Deserialize::deserialize(deserializer)?;
+        Ok(unsafe { Box::from_raw(Box::into_raw(bytes) as *mut Bytes) })
+    }
+}

src/lib.rs

@@ -38,25 +38,26 @@
 #![deny(missing_docs)]
 
 mod bytes;
+mod de;
+mod ser;
 
 #[cfg(any(feature = "std", feature = "alloc"))]
 mod bytebuf;
 
 #[cfg(feature = "alloc")]
 extern crate alloc;
 
-#[cfg(feature = "alloc")]
-use alloc::vec::Vec;
-
 #[cfg(any(feature = "std", feature = "alloc"))]
-use serde::{Deserialize, Deserializer};
+use serde::Deserializer;
 
 use serde::Serializer;
 
-pub use self::bytes::Bytes;
+pub use crate::bytes::Bytes;
+pub use crate::de::Deserialize;
+pub use crate::ser::Serialize;
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-pub use self::bytebuf::ByteBuf;
+pub use crate::bytebuf::ByteBuf;
 
 /// Serde `serialize_with` function to serialize bytes efficiently.
 ///
@@ -80,10 +81,10 @@ pub use self::bytebuf::ByteBuf;
 /// ```
 pub fn serialize<T, S>(bytes: &T, serializer: S) -> Result<S::Ok, S::Error>
 where
-    T: ?Sized + AsRef<[u8]>,
+    T: Serialize,
     S: Serializer,
 {
-    serializer.serialize_bytes(bytes.as_ref())
+    Serialize::serialize(bytes, serializer)
 }
 
 /// Serde `deserialize_with` function to deserialize bytes efficiently.
@@ -106,8 +107,8 @@ where
 #[cfg(any(feature = "std", feature = "alloc"))]
 pub fn deserialize<'de, T, D>(deserializer: D) -> Result<T, D::Error>
 where
-    T: From<Vec<u8>>,
+    T: Deserialize<'de>,
     D: Deserializer<'de>,
 {
-    ByteBuf::deserialize(deserializer).map(|buf| buf.into_inner().into())
+    Deserialize::deserialize(deserializer)
 }

src/ser.rs

@@ -0,0 +1,107 @@
+use crate::Bytes;
+use serde::Serializer;
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+use crate::ByteBuf;
+
+#[cfg(feature = "alloc")]
+use alloc::borrow::Cow;
+#[cfg(all(feature = "std", not(feature = "alloc")))]
+use std::borrow::Cow;
+
+#[cfg(feature = "alloc")]
+use alloc::boxed::Box;
+
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
+
+/// Types that can be serialized via `#[serde(with = "serde_bytes")]`.
+pub trait Serialize {
+    #[allow(missing_docs)]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer;
+}
+
+impl Serialize for [u8] {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(self)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl Serialize for Vec<u8> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(self)
+    }
+}
+
+impl Serialize for Bytes {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(self)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl Serialize for ByteBuf {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(self)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'a> Serialize for Cow<'a, [u8]> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(self)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'a> Serialize for Cow<'a, Bytes> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.serialize_bytes(self)
+    }
+}
+
+impl<'a, T> Serialize for &'a T
+where
+    T: ?Sized + Serialize,
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        (**self).serialize(serializer)
+    }
+}
+
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<T> Serialize for Box<T>
+where
+    T: ?Sized + Serialize,
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        (**self).serialize(serializer)
+    }
+}