Add Error handling for Serialization

This commit adds error handling for the crate using thiserror crate.
Also, based on the error handling, making serialization of `AAD`
eleganttly be handled with result mechanism.

Signed-off-by: Xynnn007 <xynnn@linux.alibaba.com>

Cargo.toml

@@ -10,7 +10,7 @@ license = "Apache-2.0"
 [features]
 default = [ "std" ]
 alloc = [ "serde/alloc", "serde_json/alloc" ]
-std = [ "serde/std", "serde_json/std" ]
+std = ["serde/std", "serde_json/std", "thiserror/std"]
 tee-sev = [ "sev" ]
 tee-snp = [ "sev" ]
 
@@ -19,6 +19,7 @@ base64 = "0.22.1"
 serde = { version = "1.0", default-features = false, features = ["derive"] }
 serde_json = { version = "1.0", default-features = false }
 sev = { version = "3.2.0", features = ["openssl"], optional = true }
+thiserror = { version = "2.0.3", default-features = false }
 
 [dev-dependencies]
 codicon = "3.0.0"

src/error.rs

@@ -0,0 +1,9 @@
+use thiserror::Error;
+
+pub type Result<T> = core::result::Result<T, KbsTypesError>;
+
+#[derive(Error, Debug)]
+pub enum KbsTypesError {
+    #[error("Serialize/Deserialize error")]
+    Serde,
+}

src/lib.rs

@@ -5,6 +5,9 @@
 #[cfg(feature = "alloc")]
 extern crate alloc;
 
+mod error;
+pub use error::{KbsTypesError, Result};
+
 #[cfg(all(feature = "alloc", not(feature = "std")))]
 use alloc::{collections::btree_map::BTreeMap, string::String, vec::Vec};
 use base64::{prelude::BASE64_URL_SAFE_NO_PAD, Engine};
@@ -100,18 +103,17 @@ pub struct ProtectedHeader {
 
 impl ProtectedHeader {
     /// The generation of AAD for JWE follows [A.3.5 RFC7516](https://www.rfc-editor.org/rfc/rfc7516#appendix-A.3.5)
-    pub fn generate_aad(&self) -> Vec<u8> {
-        let protected_utf8 =
-            serde_json::to_string(&self).expect("unexpected OOM when serializing ProtectedHeader");
+    pub fn generate_aad(&self) -> Result<Vec<u8>> {
+        let protected_utf8 = serde_json::to_string(&self).map_err(|_| KbsTypesError::Serde)?;
         let aad = BASE64_URL_SAFE_NO_PAD.encode(protected_utf8);
-        aad.into_bytes()
+        Ok(aad.into_bytes())
     }
 }
 
 fn serialize_base64_protected_header<S>(
     sub: &ProtectedHeader,
     serializer: S,
-) -> Result<S::Ok, S::Error>
+) -> core::result::Result<S::Ok, S::Error>
 where
     S: serde::Serializer,
 {
@@ -120,7 +122,9 @@ where
     serializer.serialize_str(&encoded)
 }
 
-fn deserialize_base64_protected_header<'de, D>(deserializer: D) -> Result<ProtectedHeader, D::Error>
+fn deserialize_base64_protected_header<'de, D>(
+    deserializer: D,
+) -> core::result::Result<ProtectedHeader, D::Error>
 where
     D: serde::Deserializer<'de>,
 {
@@ -133,15 +137,15 @@ where
     Ok(protected_header)
 }
 
-fn serialize_base64<S>(sub: &Vec<u8>, serializer: S) -> Result<S::Ok, S::Error>
+fn serialize_base64<S>(sub: &Vec<u8>, serializer: S) -> core::result::Result<S::Ok, S::Error>
 where
     S: serde::Serializer,
 {
     let encoded = BASE64_URL_SAFE_NO_PAD.encode(sub);
     serializer.serialize_str(&encoded)
 }
 
-fn deserialize_base64<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+fn deserialize_base64<'de, D>(deserializer: D) -> core::result::Result<Vec<u8>, D::Error>
 where
     D: serde::Deserializer<'de>,
 {
@@ -153,7 +157,10 @@ where
     Ok(decoded)
 }
 
-fn serialize_base64_option<S>(sub: &Option<Vec<u8>>, serializer: S) -> Result<S::Ok, S::Error>
+fn serialize_base64_option<S>(
+    sub: &Option<Vec<u8>>,
+    serializer: S,
+) -> core::result::Result<S::Ok, S::Error>
 where
     S: serde::Serializer,
 {
@@ -166,7 +173,9 @@ where
     }
 }
 
-fn deserialize_base64_option<'de, D>(deserializer: D) -> Result<Option<Vec<u8>>, D::Error>
+fn deserialize_base64_option<'de, D>(
+    deserializer: D,
+) -> core::result::Result<Option<Vec<u8>>, D::Error>
 where
     D: serde::Deserializer<'de>,
 {
@@ -273,7 +282,7 @@ mod tests {
             other_fields: BTreeMap::new(),
         };
 
-        let aad = protected_header.generate_aad();
+        let aad = protected_header.generate_aad().unwrap();
 
         assert_eq!(
             aad,