feat(citext): implement citext for postgres

sqlx-postgres/src/any.rs

@@ -13,6 +13,7 @@ use sqlx_core::connection::Connection;
 use sqlx_core::database::Database;
 use sqlx_core::describe::Describe;
 use sqlx_core::executor::Executor;
+use sqlx_core::ext::ustr::UStr;
 use sqlx_core::transaction::TransactionManager;
 
 sqlx_core::declare_driver_with_optional_migrate!(DRIVER = Postgres);
@@ -179,6 +180,7 @@ impl<'a> TryFrom<&'a PgTypeInfo> for AnyTypeInfo {
                 PgType::Float8 => AnyTypeInfoKind::Double,
                 PgType::Bytea => AnyTypeInfoKind::Blob,
                 PgType::Text => AnyTypeInfoKind::Text,
+                PgType::DeclareWithName(UStr::Static("citext")) => AnyTypeInfoKind::Text,
                 _ => {
                     return Err(sqlx_core::Error::AnyDriverError(
                         format!(

sqlx-postgres/src/type_info.rs

@@ -438,6 +438,7 @@ impl PgType {
             PgType::Int8RangeArray => Oid(3927),
             PgType::Jsonpath => Oid(4072),
             PgType::JsonpathArray => Oid(4073),
+
             PgType::Custom(ty) => ty.oid,
 
             PgType::DeclareWithOid(oid) => *oid,
@@ -855,6 +856,7 @@ impl PgType {
             PgType::Unknown => None,
             // There is no `VoidArray`
             PgType::Void => None,
+
             PgType::Custom(ty) => match &ty.kind {
                 PgTypeKind::Simple => None,
                 PgTypeKind::Pseudo => None,

sqlx-postgres/src/types/citext.rs

@@ -0,0 +1,92 @@
+use std::fmt;
+use std::fmt::{Debug, Display, Formatter};
+use std::ops::Deref;
+use std::str::FromStr;
+use sqlx_core::decode::Decode;
+use sqlx_core::encode::{Encode, IsNull};
+use sqlx_core::error::BoxDynError;
+use sqlx_core::types::Type;
+use crate::{PgArgumentBuffer, PgHasArrayType, PgTypeInfo, PgValueRef, Postgres};
+use crate::types::array_compatible;
+
+/// Text type for case insensitive searching in Postgres.
+///
+/// See https://www.postgresql.org/docs/current/citext.html
+///
+/// ### Note: Extension Required
+/// The `citext` extension is not enabled by default in Postgres. You will need to do so explicitly:
+///
+/// ```ignore
+/// CREATE EXTENSION IF NOT EXISTS "citext";
+/// ```
+
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct PgCitext(String);
+
+impl PgCitext {
+    pub fn new(s: String) -> Self {
+        Self(s)
+    }
+}
+
+impl Type<Postgres> for PgCitext {
+    fn type_info() -> PgTypeInfo {
+        // Since `ltree` is enabled by an extension, it does not have a stable OID.
+        PgTypeInfo::with_name("citext")
+    }
+
+    fn compatible(ty: &PgTypeInfo) -> bool {
+        <&str as Type<Postgres>>::compatible(ty)
+    }
+}
+
+impl Deref for PgCitext {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        self.0.as_str()
+    }
+}
+
+impl From<String> for PgCitext {
+    fn from(value: String) -> Self {
+        Self::new(value)
+    }
+}
+
+impl FromStr for PgCitext {
+    type Err = core::convert::Infallible;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(PgCitext(s.parse()?))
+    }
+}
+
+impl Display for PgCitext {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+impl PgHasArrayType for PgCitext {
+    fn array_type_info() -> PgTypeInfo {
+        PgTypeInfo::with_name("_citext")
+    }
+
+    fn array_compatible(ty: &PgTypeInfo) -> bool {
+        array_compatible::<&str>(ty)
+    }
+}
+
+
+impl Encode<'_, Postgres> for PgCitext {
+    fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> IsNull {
+        <&str as Encode<Postgres>>::encode(&**self, buf)
+    }
+}
+
+impl Decode<'_, Postgres> for PgCitext {
+    fn decode(value: PgValueRef<'_>) -> Result<Self, BoxDynError> {
+        Ok(PgCitext(value.as_str()?.to_owned()))
+    }
+}

sqlx-postgres/src/types/mod.rs

@@ -180,6 +180,7 @@ mod int;
 mod interval;
 mod lquery;
 mod ltree;
+mod citext;
 // Not behind a Cargo feature because we require JSON in the driver implementation.
 mod json;
 mod money;
@@ -235,6 +236,7 @@ pub use ltree::PgLTreeParseError;
 pub use money::PgMoney;
 pub use oid::Oid;
 pub use range::PgRange;
+pub use citext::PgCitext;
 
 #[cfg(any(feature = "chrono", feature = "time"))]
 pub use time_tz::PgTimeTz;

sqlx-postgres/src/types/str.rs

@@ -18,6 +18,7 @@ impl Type<Postgres> for str {
             PgTypeInfo::BPCHAR,
             PgTypeInfo::VARCHAR,
             PgTypeInfo::UNKNOWN,
+            PgTypeInfo::with_name("citext")
         ]
         .contains(ty)
     }

tests/postgres/types.rs

@@ -2,7 +2,7 @@ extern crate time_ as time;
 
 use std::ops::Bound;
 
-use sqlx::postgres::types::{Oid, PgInterval, PgMoney, PgRange};
+use sqlx::postgres::types::{Oid, PgInterval, PgMoney, PgRange, PgCitext};
 use sqlx::postgres::Postgres;
 use sqlx_test::{test_decode_type, test_prepared_type, test_type};
 
@@ -79,7 +79,7 @@ test_type!(string_vec<Vec<String>>(Postgres,
         == vec!["", "\""],
 
     "array['Hello, World', '', 'Goodbye']::text[]"
-        == vec!["Hello, World", "", "Goodbye"]
+        == vec!["Hello, World", "", "Goodbye"],
 ));
 
 test_type!(string_array<[String; 3]>(Postgres,
@@ -549,6 +549,15 @@ test_prepared_type!(money_vec<Vec<PgMoney>>(Postgres,
     "array[123.45,420.00,666.66]::money[]" == vec![PgMoney(12345), PgMoney(42000), PgMoney(66666)],
 ));
 
+test_prepared_type!(citext_array<Vec<PgCitext>>(Postgres,
+    "array['one','two','three']::citext[]" == vec![
+        PgCitext::new("one".to_string()),
+        PgCitext::new("two".to_string()),
+        PgCitext::new("three".to_string()),
+    ],
+));
+
+
 // FIXME: needed to disable `ltree` tests in version that don't have a binary format for it
 // but `PgLTree` should just fall back to text format
 #[cfg(any(postgres_14, postgres_15))]