Add serialization traits

This commit adds experimental version of new serialization traits.
Blanket implementation are provided to support older traits.

scylla-cql/src/lib.rs

@@ -3,6 +3,8 @@ pub mod frame;
 #[macro_use]
 pub mod macros;
 
+pub mod types;
+
 pub use crate::frame::response::cql_to_rust;
 pub use crate::frame::response::cql_to_rust::FromRow;
 

scylla-cql/src/types/mod.rs

@@ -0,0 +1 @@
+pub mod serialize;

scylla-cql/src/types/serialize/mod.rs

@@ -0,0 +1,6 @@
+use std::{any::Any, sync::Arc};
+
+pub mod row;
+pub mod value;
+
+type SerializationError = Arc<dyn Any + Send + Sync>;

scylla-cql/src/types/serialize/row.rs

@@ -0,0 +1,49 @@
+use std::sync::Arc;
+
+use crate::frame::response::result::ColumnSpec;
+use crate::frame::value::ValueList;
+
+use super::SerializationError;
+
+pub struct RowSerializationContext<'a> {
+    columns: &'a [ColumnSpec],
+}
+
+impl<'a> RowSerializationContext<'a> {
+    #[inline]
+    pub fn columns(&self) -> &'a [ColumnSpec] {
+        self.columns
+    }
+
+    // TODO: change RowSerializationContext to make this faster
+    #[inline]
+    pub fn column_by_name(&self, target: &str) -> Option<&ColumnSpec> {
+        self.columns.iter().find(|&c| c.name == target)
+    }
+}
+
+pub trait SerializeRow {
+    fn preliminary_type_check(ctx: &RowSerializationContext<'_>) -> Result<(), SerializationError>;
+    fn serialize(
+        &self,
+        ctx: &RowSerializationContext<'_>,
+        out: &mut Vec<u8>,
+    ) -> Result<(), SerializationError>;
+}
+
+impl<T: ValueList> SerializeRow for T {
+    fn preliminary_type_check(
+        _ctx: &RowSerializationContext<'_>,
+    ) -> Result<(), SerializationError> {
+        Ok(())
+    }
+
+    fn serialize(
+        &self,
+        _ctx: &RowSerializationContext<'_>,
+        out: &mut Vec<u8>,
+    ) -> Result<(), SerializationError> {
+        self.write_to_request(out)
+            .map_err(|err| Arc::new(err) as SerializationError)
+    }
+}

scylla-cql/src/types/serialize/value.rs

@@ -0,0 +1,22 @@
+use std::sync::Arc;
+
+use crate::frame::response::result::ColumnType;
+use crate::frame::value::Value;
+
+use super::SerializationError;
+
+pub trait SerializeCql {
+    fn preliminary_type_check(typ: &ColumnType) -> Result<(), SerializationError>;
+    fn serialize(&self, typ: &ColumnType, buf: &mut Vec<u8>) -> Result<(), SerializationError>;
+}
+
+impl<T: Value> SerializeCql for T {
+    fn preliminary_type_check(_typ: &ColumnType) -> Result<(), SerializationError> {
+        Ok(())
+    }
+
+    fn serialize(&self, _typ: &ColumnType, buf: &mut Vec<u8>) -> Result<(), SerializationError> {
+        self.serialize(buf)
+            .map_err(|err| Arc::new(err) as SerializationError)
+    }
+}