feat: add ScopedIdentifier type

Author: svix-jbrown

CHANGELOG.md

@@ -25,7 +25,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - query: due to `RowBinaryWithNamesAndTypes` format usage, there might be an impact on fetch performance, which largely
   depends on how the dataset is defined. If you notice decreased performance, consider disabling validation by using
   `Client::with_validation(false)`.
-- serde: it is now possible to deserialize Map ClickHouse type into `HashMap<K, V>` (or `BTreeMap`, `IndexMap`, 
+- serde: it is now possible to deserialize Map ClickHouse type into `HashMap<K, V>` (or `BTreeMap`, `IndexMap`,
   `DashMap`, etc.).
 
 ### Added
@@ -36,6 +36,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - types: a new crate `clickhouse-types` was added to the project workspace. This crate is required for
   `RowBinaryWithNamesAndTypes` struct definition validation, as it contains ClickHouse data types AST, as well as
   functions and utilities to parse the types out of the ClickHouse server response. ([#221]).
+- sql: added `ScopedIdentifier` type to represent scoped identifiers (e.g., `table.column`) safely as bind values
 
 [#221]: https://github.com/ClickHouse/clickhouse-rs/pull/221
 [#245]: https://github.com/ClickHouse/clickhouse-rs/pull/245

src/sql/bind.rs

@@ -31,3 +31,38 @@ impl Bind for Identifier<'_> {
         escape::identifier(self.0, dst).map_err(|err| err.to_string())
     }
 }
+
+#[derive(Clone, Copy)]
+pub struct ScopedIdentifier<'a>(pub &'a str, pub &'a str);
+
+#[sealed]
+impl Bind for ScopedIdentifier<'_> {
+    #[inline]
+    fn write(&self, dst: &mut impl fmt::Write) -> Result<(), String> {
+        if self.0.len() > 0 {
+            escape::identifier(self.0, dst).map_err(|err| err.to_string())?;
+            dst.write_char('.').map_err(|err| err.to_string())?;
+        }
+        escape::identifier(self.1, dst).map_err(|err| err.to_string())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{Bind, ScopedIdentifier};
+
+    fn bind_to_string(b: impl Bind) -> String {
+        let mut s = String::new();
+        b.write(&mut s).expect("bind should succeed");
+        s
+    }
+
+    #[test]
+    fn test_scoped_identifier() {
+        assert_eq!(
+            bind_to_string(ScopedIdentifier("foo", "bar baz")),
+            "`foo`.`bar baz`"
+        );
+        assert_eq!(bind_to_string(ScopedIdentifier("", "bar baz")), "`bar baz`");
+    }
+}

src/sql/mod.rs

@@ -5,7 +5,7 @@ use crate::{
     row::{self, Row},
 };
 
-pub use bind::{Bind, Identifier};
+pub use bind::{Bind, Identifier, ScopedIdentifier};
 
 mod bind;
 pub(crate) mod escape;