Made SerdeDecoder attempt to allocate a string before complaining abo…

…ut being able to decode borrowed data (#475)

Cargo.toml

@@ -45,6 +45,8 @@ serde_json = "1.0.68"
 tempfile = "3.2.0"
 criterion = "0.3"
 rand = "0.8"
+uuid = { version = "0.8", features = ["serde"] }
+chrono = { version = "0.4", features = ["serde"] }
 
 [[bench]]
 name = "varint"

src/features/serde/de_owned.rs

@@ -121,7 +121,16 @@ impl<'a, 'de, DE: Decoder> Deserializer<'de> for SerdeDecoder<'a, DE> {
         visitor.visit_char(Decode::decode(&mut self.de)?)
     }
 
-    fn deserialize_str<V>(self, _visitor: V) -> Result<V::Value, Self::Error>
+    #[cfg(feature = "alloc")]
+    fn deserialize_str<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: serde_incl::de::Visitor<'de>,
+    {
+        visitor.visit_string(Decode::decode(&mut self.de)?)
+    }
+
+    #[cfg(not(feature = "alloc"))]
+    fn deserialize_str<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
     where
         V: serde_incl::de::Visitor<'de>,
     {
@@ -135,6 +144,15 @@ impl<'a, 'de, DE: Decoder> Deserializer<'de> for SerdeDecoder<'a, DE> {
         visitor.visit_string(Decode::decode(&mut self.de)?)
     }
 
+    #[cfg(feature = "alloc")]
+    fn deserialize_bytes<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: serde_incl::de::Visitor<'de>,
+    {
+        visitor.visit_byte_buf(Decode::decode(&mut self.de)?)
+    }
+
+    #[cfg(not(feature = "alloc"))]
     fn deserialize_bytes<V>(self, _visitor: V) -> Result<V::Value, Self::Error>
     where
         V: serde_incl::de::Visitor<'de>,

tests/issues.rs

@@ -11,3 +11,6 @@ mod issue_467;
 
 #[path = "issues/issue_459.rs"]
 mod issue_459;
+
+#[path = "issues/issue_474.rs"]
+mod issue_474;

tests/issues/issue_474.rs

@@ -0,0 +1,97 @@
+#![cfg(all(feature = "serde", feature = "std"))]
+
+extern crate std;
+
+use bincode::config::Configuration;
+use chrono::{DateTime, Utc};
+use serde_incl::de::DeserializeOwned;
+use std::collections::HashMap;
+use std::prelude::rust_2021::*;
+use uuid::Uuid;
+
+#[derive(serde_derive::Serialize, serde_derive::Deserialize, PartialEq, Debug)]
+#[serde(crate = "serde_incl")]
+pub struct MyStruct {
+    name: String,
+}
+
+#[derive(serde_derive::Serialize, serde_derive::Deserialize, PartialEq, Debug)]
+#[serde(crate = "serde_incl")]
+pub struct CustomerTest {
+    pub id: Option<Uuid>,
+    pub email_address: Option<String>,
+    pub is_active: Option<bool>,
+    pub date_stamp: Option<DateTime<Utc>>,
+}
+
+#[test]
+fn test() {
+    let test = MyStruct {
+        name: "Test Value".into(),
+    };
+    let cache_id = Uuid::nil();
+    let cache = MemCache::default();
+
+    cache.set_data::<MyStruct>(&cache_id, &test, 5).unwrap();
+    let model = cache.get_data::<MyStruct>(&cache_id).unwrap();
+    assert_eq!(test, model);
+
+    let test = CustomerTest {
+        id: Some(Uuid::nil()),
+        email_address: Some("foo@bar".into()),
+        is_active: None,
+        date_stamp: Some(Utc::now()),
+    };
+
+    cache.set_data::<CustomerTest>(&cache_id, &test, 5).unwrap();
+    let model = cache.get_data::<CustomerTest>(&cache_id).unwrap();
+    assert_eq!(test, model);
+}
+
+#[derive(Default)]
+struct MemCache {
+    cache: std::sync::RwLock<HashMap<Uuid, CacheItem>>,
+}
+
+impl MemCache {
+    fn set_data<T>(
+        &self,
+        key: &Uuid,
+        cache_data: &T,
+        expire_seconds: i64,
+    ) -> Result<(), bincode::error::EncodeError>
+    where
+        T: Send + Sync + serde_incl::Serialize,
+    {
+        let config = Configuration::standard();
+        let mut guard = self.cache.write().unwrap();
+
+        let encoded = bincode::serde::encode_to_vec(&cache_data, config)?;
+        let cache_item = CacheItem::new(encoded, expire_seconds);
+
+        guard.insert(key.clone(), cache_item);
+        Ok(())
+    }
+
+    fn get_data<T>(&self, key: &Uuid) -> Result<T, bincode::error::DecodeError>
+    where
+        T: Send + Sync + DeserializeOwned,
+    {
+        let config = Configuration::standard();
+        let guard = self.cache.read().unwrap();
+        let cache_item = guard.get(key).unwrap();
+        let (decoded, _len): (T, usize) =
+            bincode::serde::decode_from_slice(&cache_item.payload[..], config)?;
+        Ok(decoded)
+    }
+}
+
+struct CacheItem {
+    payload: Vec<u8>,
+}
+
+impl CacheItem {
+    fn new(payload: Vec<u8>, _expire_seconds: i64) -> Self {
+        Self { payload }
+    }
+}