From 74b8bb2627962bb55d87715045b3f1201bc7051d Mon Sep 17 00:00:00 2001
From: polazarus <polazarus@users.noreply.github.com>
Date: Thu, 10 Aug 2023 16:07:16 +0200
Subject: [PATCH] improve bytes serde

---
 Cargo.toml         |   5 +-
 src/bytes/serde.rs | 129 +++++++++++----------------------------------
 2 files changed, 36 insertions(+), 98 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index a6f152e..8b1516b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,6 +15,7 @@ rust-version = "1.64.0"
 
 [features]
 unstable = []
+serde = ["dep:serde", "dep:serde_bytes"]
 
 [[bench]]
 name = "competition"
@@ -25,8 +26,10 @@ arcstr = "1.1.5"
 fastrand = "1.9.0"
 flexstr = "0.9.2"
 imstr = "0.2.0"
-serde_test = "1.0.163"
+serde_test = "1.0"
 serde = { version = "1.0.60", features = ["derive"] }
+serde_json = "1.0"
 
 [dependencies]
 serde = { version = "1.0.60", optional = true }
+serde_bytes = { version = "0.11", optional = true }
diff --git a/src/bytes/serde.rs b/src/bytes/serde.rs
index 94666c2..4153ebf 100644
--- a/src/bytes/serde.rs
+++ b/src/bytes/serde.rs
@@ -1,6 +1,5 @@
-use std::marker::PhantomData;
+use std::borrow::Cow;
 
-use serde::de::Visitor;
 use serde::{Deserialize, Serialize};
 
 use super::HipByt;
@@ -18,49 +17,6 @@ where
     }
 }
 
-#[derive(Clone, Copy, Debug)]
-struct BytesVisitor;
-
-impl<'de> Visitor<'de> for BytesVisitor {
-    type Value = Vec<u8>;
-
-    fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
-    where
-        E: serde::de::Error,
-    {
-        Ok(v)
-    }
-
-    fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
-    where
-        E: serde::de::Error,
-    {
-        Ok(v.into())
-    }
-
-    fn visit_borrowed_bytes<E>(self, v: &'de [u8]) -> Result<Self::Value, E>
-    where
-        E: serde::de::Error,
-    {
-        Ok(v.into())
-    }
-
-    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
-    where
-        A: serde::de::SeqAccess<'de>,
-    {
-        let mut v = seq.size_hint().map_or_else(Vec::new, Vec::with_capacity);
-        while let Some(e) = seq.next_element()? {
-            v.push(e);
-        }
-        Ok(v)
-    }
-
-    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
-        write!(formatter, "bytes")
-    }
-}
-
 impl<'de, 'borrow, B> Deserialize<'de> for HipByt<'borrow, B>
 where
     B: Backend,
@@ -69,61 +25,16 @@ where
     where
         D: serde::Deserializer<'de>,
     {
-        let v = deserializer.deserialize_byte_buf(BytesVisitor)?;
+        let v: Vec<u8> = serde_bytes::deserialize(deserializer)?;
         Ok(Self::from(v))
     }
 }
 
-#[derive(Clone, Copy, Debug)]
-struct BorrowingByteVisitor<B>(PhantomData<B>);
-
-impl<'de, B> Visitor<'de> for BorrowingByteVisitor<B>
-where
-    B: Backend,
-{
-    type Value = HipByt<'de, B>;
-
-    fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
-    where
-        E: serde::de::Error,
-    {
-        Ok(v.into())
-    }
-
-    fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
-    where
-        E: serde::de::Error,
-    {
-        Ok(v.into())
-    }
-
-    fn visit_borrowed_bytes<E>(self, v: &'de [u8]) -> Result<Self::Value, E>
-    where
-        E: serde::de::Error,
-    {
-        Ok(HipByt::borrowed(v))
-    }
-
-    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
-    where
-        A: serde::de::SeqAccess<'de>,
-    {
-        let mut v = seq.size_hint().map_or_else(Vec::new, Vec::with_capacity);
-        while let Some(e) = seq.next_element()? {
-            v.push(e);
-        }
-        Ok(v.into())
-    }
-
-    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
-        write!(formatter, "bytes")
-    }
-}
-
 /// Deserializes a `HipByt` as a borrow if possible.
 ///
 /// ```rust
 /// # use serde::Deserialize;
+/// # use serde_json;
 /// use hipstr::bytes::HipByt;
 /// use hipstr::Local;
 /// #[derive(Deserialize)]
@@ -131,14 +42,22 @@ where
 ///     #[serde(borrow, deserialize_with = "hipstr::bytes::serde::borrowing_deserialize")]
 ///     field: HipByt<'a, Local>,
 /// }
-/// # fn main() {}
+/// # fn main() {
+/// let s: MyStruct = serde_json::from_str(r#"{"field": "abc"}"#).unwrap();
+/// assert!(s.field.is_borrowed());
+/// # }
 /// ```
-pub fn borrowing_deserialize<'de, D, B>(deserializer: D) -> Result<HipByt<'de, B>, D::Error>
+///
+/// # Errors
+///
+/// Returns a deserializer if either the serialization is incorrect or an unexpected value is encountered.
+pub fn borrowing_deserialize<'de: 'a, 'a, D, B>(deserializer: D) -> Result<HipByt<'a, B>, D::Error>
 where
     D: serde::Deserializer<'de>,
     B: Backend,
 {
-    deserializer.deserialize_byte_buf(BorrowingByteVisitor(PhantomData))
+    let cow: Cow<'de, [u8]> = serde_bytes::Deserialize::deserialize(deserializer)?;
+    Ok(HipByt::from(cow))
 }
 
 #[cfg(test)]
@@ -147,6 +66,7 @@ mod tests {
         assert_de_tokens, assert_de_tokens_error, assert_ser_tokens, assert_tokens, Token,
     };
 
+    use crate::bytes::serde::borrowing_deserialize;
     use crate::HipByt;
 
     #[test]
@@ -177,8 +97,23 @@ mod tests {
     #[test]
     fn test_de_error() {
         assert_de_tokens_error::<HipByt>(
-            &[Token::Str("")],
-            "invalid type: string \"\", expected bytes",
+            &[Token::F32(0.0)],
+            "invalid type: floating point `0`, expected byte array",
         );
     }
+
+    #[test]
+    fn test_serde_borrowing() {
+        use serde::de::Deserialize;
+        use serde_json::Value;
+
+        use super::super::HipByt;
+        use crate::Local;
+
+        let v = Value::from("abcdefghijklmnopqrstuvwxyz");
+        let h1: HipByt<'_, Local> = borrowing_deserialize(&v).unwrap();
+        let h2: HipByt<'_, Local> = Deserialize::deserialize(&v).unwrap();
+        assert!(h1.is_borrowed());
+        assert!(!h2.is_borrowed());
+    }
 }