errors: Low level (de)ser errors

scylla-cql/src/frame/frame_errors.rs

@@ -35,6 +35,8 @@ pub enum FrameError {
 
 #[derive(Error, Debug)]
 pub enum ParseError {
+    #[error("Low-level deserialization failed: {0}")]
+    LowLevelDeserializationError(#[from] LowLevelDeserializationError),
     #[error("Could not serialize frame: {0}")]
     BadDataToSerialize(String),
     #[error("Could not deserialize frame: {0}")]
@@ -52,3 +54,34 @@ pub enum ParseError {
     #[error(transparent)]
     CqlTypeError(#[from] CqlTypeError),
 }
+
+/// A low level deserialization error.
+///
+/// This type of error is returned when deserialization
+/// of some primitive value fails.
+///
+/// Possible error kinds:
+/// - generic io error - reading from buffer failed
+/// - out of range integer conversion
+/// - conversion errors - e.g. slice-to-array or primitive-to-enum
+/// - not enough bytes in the buffer to deserialize a value
+#[non_exhaustive]
+#[derive(Error, Debug)]
+pub enum LowLevelDeserializationError {
+    #[error(transparent)]
+    IoError(#[from] std::io::Error),
+    #[error(transparent)]
+    TryFromIntError(#[from] std::num::TryFromIntError),
+    #[error("Failed to convert slice into array: {0}")]
+    TryFromSliceError(#[from] std::array::TryFromSliceError),
+    #[error("Not enough bytes! expected: {expected}, received: {received}")]
+    TooFewBytesReceived { expected: usize, received: usize },
+    #[error("Invalid value length: {0}")]
+    InvalidValueLength(i32),
+    #[error("Unknown consistency: {0}")]
+    UnknownConsistency(#[from] TryFromPrimitiveError<u16>),
+    #[error("Invalid inet bytes length: {0}")]
+    InvalidInetLength(u8),
+    #[error("UTF8 deserialization failed: {0}")]
+    UTF8DeserializationError(#[from] std::str::Utf8Error),
+}

scylla-cql/src/frame/mod.rs

@@ -188,7 +188,7 @@ pub fn parse_response_body_extensions(
 
     let trace_id = if flags & FLAG_TRACING != 0 {
         let buf = &mut &*body;
-        let trace_id = types::read_uuid(buf)?;
+        let trace_id = types::read_uuid(buf).map_err(frame_errors::ParseError::from)?;
         body.advance(16);
         Some(trace_id)
     } else {
@@ -198,7 +198,7 @@ pub fn parse_response_body_extensions(
     let warnings = if flags & FLAG_WARNING != 0 {
         let body_len = body.len();
         let buf = &mut &*body;
-        let warnings = types::read_string_list(buf)?;
+        let warnings = types::read_string_list(buf).map_err(frame_errors::ParseError::from)?;
         let buf_len = buf.len();
         body.advance(body_len - buf_len);
         warnings
@@ -209,7 +209,7 @@ pub fn parse_response_body_extensions(
     let custom_payload = if flags & FLAG_CUSTOM_PAYLOAD != 0 {
         let body_len = body.len();
         let buf = &mut &*body;
-        let payload_map = types::read_bytes_map(buf)?;
+        let payload_map = types::read_bytes_map(buf).map_err(frame_errors::ParseError::from)?;
         let buf_len = buf.len();
         body.advance(body_len - buf_len);
         Some(payload_map)

scylla-cql/src/frame/request/auth_response.rs

@@ -12,6 +12,6 @@ impl SerializableRequest for AuthResponse {
     const OPCODE: RequestOpcode = RequestOpcode::AuthResponse;
 
     fn serialize(&self, buf: &mut Vec<u8>) -> Result<(), ParseError> {
-        write_bytes_opt(self.response.as_ref(), buf)
+        Ok(write_bytes_opt(self.response.as_ref(), buf)?)
     }
 }

scylla-cql/src/frame/response/result.rs

@@ -5,7 +5,9 @@ use crate::frame::value::{
 };
 use crate::frame::{frame_errors::ParseError, types};
 use crate::types::deserialize::result::{RowIterator, TypedRowIterator};
-use crate::types::deserialize::value::{DeserializeValue, MapIterator, UdtIterator};
+use crate::types::deserialize::value::{
+    mk_deser_err, BuiltinDeserializationErrorKind, DeserializeValue, MapIterator, UdtIterator,
+};
 use crate::types::deserialize::{DeserializationError, FrameSlice};
 use bytes::{Buf, Bytes};
 use std::borrow::Cow;
@@ -643,7 +645,10 @@ fn deser_prepared_metadata(buf: &mut &[u8]) -> StdResult<PreparedMetadata, Parse
     })
 }
 
-pub fn deser_cql_value(typ: &ColumnType, buf: &mut &[u8]) -> StdResult<CqlValue, ParseError> {
+pub fn deser_cql_value(
+    typ: &ColumnType,
+    buf: &mut &[u8],
+) -> StdResult<CqlValue, DeserializationError> {
     use ColumnType::*;
 
     if buf.is_empty() {
@@ -662,10 +667,10 @@ pub fn deser_cql_value(typ: &ColumnType, buf: &mut &[u8]) -> StdResult<CqlValue,
 
     Ok(match typ {
         Custom(type_str) => {
-            return Err(ParseError::BadIncomingData(format!(
-                "Support for custom types is not yet implemented: {}",
-                type_str
-            )));
+            return Err(mk_deser_err::<CqlValue>(
+                typ,
+                BuiltinDeserializationErrorKind::CustomTypeNotSupported(type_str.to_string()),
+            ))
         }
         Ascii => {
             let s = String::deserialize(typ, v)?;
@@ -784,14 +789,15 @@ pub fn deser_cql_value(typ: &ColumnType, buf: &mut &[u8]) -> StdResult<CqlValue,
         Tuple(type_names) => {
             let t = type_names
                 .iter()
-                .map(|typ| {
-                    types::read_bytes_opt(buf).and_then(|v| {
-                        v.map(|v| {
-                            CqlValue::deserialize(typ, Some(FrameSlice::new_borrowed(v)))
-                                .map_err(Into::into)
-                        })
+                .map(|typ| -> StdResult<_, DeserializationError> {
+                    let raw = types::read_bytes_opt(buf).map_err(|e| {
+                        mk_deser_err::<CqlValue>(
+                            typ,
+                            BuiltinDeserializationErrorKind::RawCqlBytesReadError(e),
+                        )
+                    })?;
+                    raw.map(|v| CqlValue::deserialize(typ, Some(FrameSlice::new_borrowed(v))))
                         .transpose()
-                    })
                 })
                 .collect::<StdResult<_, _>>()?;
             CqlValue::Tuple(t)