chore: check xlang flag

rust/fury/src/deserializer.rs

@@ -15,6 +15,7 @@
 use crate::{
     error::Error,
     types::{FuryMeta, RefFlag},
+    Language,
 };
 use chrono::{DateTime, Days, NaiveDate, NaiveDateTime, TimeZone, Utc};
 use std::{
@@ -236,10 +237,13 @@ impl<'de, 'bf: 'de> DeserializerState<'de, 'bf> {
         }
     }
 
-    fn head(&mut self) {
+    fn head(&mut self) -> Result<(), Error> {
         let _bitmap = self.reader.u8();
-        let _language = self.reader.u8();
-        self.reader.skip(8); // native offset and size
+        let language: Language = self.reader.u8().try_into()?;
+        match language {
+            Language::XLANG => Ok(()),
+            _ => Err(Error::UnsupportLanguage { language }),
+        }
     }
 
     pub fn read_tag(&mut self) -> Result<&str, Error> {
@@ -264,6 +268,6 @@ impl<'de, 'bf: 'de> DeserializerState<'de, 'bf> {
 pub fn from_buffer<T: Deserialize>(bf: &[u8]) -> Result<T, Error> {
     let reader = Reader::new(bf);
     let mut deserializer = DeserializerState::new(reader);
-    deserializer.head();
+    deserializer.head()?;
     <T as Deserialize>::deserialize(&mut deserializer)
 }

rust/fury/src/error.rs

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::FieldType;
+use crate::{FieldType, Language};
 
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
@@ -42,4 +42,10 @@ pub enum Error {
 
     #[error("Bad Tag Type: {0}")]
     TagType(u8),
+
+    #[error("Only Xlang supported; receive: {language:?}")]
+    UnsupportLanguage { language: Language },
+
+    #[error("Unsupported Language Code; receive: {code:?}")]
+    UnsupportLanguageCode { code: u8 },
 }

rust/fury/src/types.rs

@@ -19,6 +19,8 @@ use std::{
 
 use chrono::{NaiveDate, NaiveDateTime};
 
+use crate::Error;
+
 pub trait FuryMeta {
     fn ty() -> FieldType;
 
@@ -235,6 +237,7 @@ pub mod config_flags {
     pub const IS_OUT_OF_BAND_FLAG: u8 = 8;
 }
 
+#[derive(Debug)]
 pub enum Language {
     XLANG = 0,
     JAVA = 1,
@@ -245,5 +248,22 @@ pub enum Language {
     RUST = 6,
 }
 
+impl TryFrom<u8> for Language {
+    type Error = Error;
+
+    fn try_from(num: u8) -> Result<Self, Error> {
+        match num {
+            0 => Ok(Language::XLANG),
+            1 => Ok(Language::JAVA),
+            2 => Ok(Language::PYTHON),
+            3 => Ok(Language::CPP),
+            4 => Ok(Language::GO),
+            5 => Ok(Language::JAVASCRIPT),
+            6 => Ok(Language::RUST),
+            _ => Err(Error::UnsupportLanguageCode { code: num }),
+        }
+    }
+}
+
 // every object start with i8 i16 reference flag and type flag
 pub const SIZE_OF_REF_AND_TYPE: usize = mem::size_of::<i8>() + mem::size_of::<i16>();