Add methods to look at params and results

Author: sfackler

src/lib.rs

@@ -421,7 +421,8 @@ impl<'self> PostgresTransaction<'self> {
 }
 
 pub trait PostgresStatement {
-    fn num_params(&self) -> uint;
+    fn param_types<'a>(&'a self) -> &'a [PostgresType];
+    fn result_descriptions<'a>(&'a self) -> &'a [ResultDescription];
     fn update(&self, params: &[&ToSql]) -> uint;
     fn try_update(&self, params: &[&ToSql]) -> Result<uint, PostgresDbError>;
     fn query<'a>(&'a self, params: &[&ToSql]) -> PostgresResult<'a>;
@@ -438,6 +439,7 @@ pub struct NormalPostgresStatement<'self> {
     priv next_portal_id: Cell<uint>
 }
 
+#[deriving(Eq)]
 pub struct ResultDescription {
     name: ~str,
     ty: PostgresType
@@ -548,8 +550,12 @@ impl<'self> NormalPostgresStatement<'self> {
 }
 
 impl<'self> PostgresStatement for NormalPostgresStatement<'self> {
-    fn num_params(&self) -> uint {
-        self.param_types.len()
+    fn param_types<'a>(&'a self) -> &'a [PostgresType] {
+        self.param_types.as_slice()
+    }
+
+    fn result_descriptions<'a>(&'a self) -> &'a [ResultDescription] {
+        self.result_desc.as_slice()
     }
 
     fn update(&self, params: &[&ToSql]) -> uint {
@@ -618,8 +624,12 @@ pub struct TransactionalPostgresStatement<'self> {
 }
 
 impl<'self> PostgresStatement for TransactionalPostgresStatement<'self> {
-    fn num_params(&self) -> uint {
-        self.stmt.num_params()
+    fn param_types<'a>(&'a self) -> &'a [PostgresType] {
+        self.stmt.param_types()
+    }
+
+    fn result_descriptions<'a>(&'a self) -> &'a [ResultDescription] {
+        self.stmt.result_descriptions()
     }
 
     fn update(&self, params: &[&ToSql]) -> uint {

src/test.rs

@@ -7,7 +7,7 @@ use std::f32;
 use std::f64;
 
 use postgres::*;
-use postgres::types::{ToSql, FromSql};
+use postgres::types::{ToSql, FromSql, PgInt4, PgVarchar};
 
 #[test]
 fn test_prepare_err() {
@@ -88,6 +88,22 @@ fn test_lazy_query() {
     }
 }
 
+#[test]
+fn test_param_types() {
+    let conn = PostgresConnection::connect("postgres://postgres@127.0.0.1:5432");
+    let stmt = conn.prepare("SELECT $1::INT, $2::VARCHAR");
+    assert_eq!(stmt.param_types(), [PgInt4, PgVarchar]);
+}
+
+#[test]
+fn test_result_descriptions() {
+    let conn = PostgresConnection::connect("postgres://postgres@127.0.0.1:5432");
+    let stmt = conn.prepare("SELECT 1::INT as a, 'hi'::VARCHAR as b");
+    assert_eq!(stmt.result_descriptions(),
+               [ResultDescription { name: ~"a", ty: PgInt4},
+                ResultDescription { name: ~"b", ty: PgVarchar}]);
+}
+
 fn test_type<T: Eq+ToSql+FromSql>(sql_type: &str, values: &[T]) {
     let conn = PostgresConnection::connect("postgres://postgres@127.0.0.1:5432");
     conn.update("CREATE TEMPORARY TABLE foo (

src/types.rs

@@ -25,6 +25,7 @@ static BPCHAROID: Oid = 1042;
 static VARCHAROID: Oid = 1043;
 static UUIDOID: Oid = 2950;
 
+#[deriving(Eq)]
 pub enum PostgresType {
     PgBool,
     PgByteA,