refactor(mysql): merge and cleanup recv_columns!

sqlx-mysql/src/connection/executor/columns.rs

@@ -5,9 +5,14 @@ use crate::protocol::ColumnDefinition;
 use crate::stream::MySqlStream;
 
 macro_rules! impl_recv_columns {
-    ($(@$blocking:ident)? $num_columns:ident, $stream:ident, $cmd:ident) => {{
+    ($(@$blocking:ident)? $store:expr, $num_columns:ident, $stream:ident, $cmd:ident) => {{
         #[allow(clippy::cast_possible_truncation)]
-        let mut columns = Vec::<ColumnDefinition>::with_capacity($num_columns as usize);
+        let mut columns = if $store {
+            Vec::<ColumnDefinition>::with_capacity($num_columns as usize)
+        } else {
+            // we are going to drop column definitions, do not allocate
+            Vec::new()
+        };
 
         // STATE: remember how many columns are in this result set
         $cmd.columns = $num_columns;
@@ -16,7 +21,14 @@ macro_rules! impl_recv_columns {
             // STATE: remember that we are expecting the #index column definition
             $cmd.state = QueryState::ColumnDefinition { index };
 
-            columns.push(read_packet!($(@$blocking)? $stream).deserialize()?);
+            // read in definition and only deserialize if we are saving
+            // the column definitions
+
+            let packet = read_packet!($(@$blocking)? $stream);
+
+            if $store {
+                columns.push(packet.deserialize()?);
+            }
         }
 
         // STATE: remember that we are now expecting a row or the end
@@ -26,93 +38,40 @@ macro_rules! impl_recv_columns {
     }};
 }
 
-macro_rules! impl_recv_and_drop_columns {
-    ($(@$blocking:ident)? $num_columns:ident, $stream:ident, $cmd:ident) => {{
-        // STATE: remember how many columns are in this result set
-        $cmd.columns = $num_columns;
-
-        for index in 0..$num_columns {
-            // STATE: remember that we are expecting the #index column definition
-            $cmd.state = QueryState::ColumnDefinition { index };
-
-            // read and immediately drop the column definition packet
-            // this method is only invoked when we don't care about query results
-            let _ = read_packet!($(@$blocking)? $stream);
-        }
-
-        // STATE: remember that we are now expecting a row or the end
-        $cmd.state = QueryState::QueryStep;
-
-        Ok(())
-    }};
-}
-
 impl<Rt: Runtime> MySqlStream<Rt> {
     #[cfg(feature = "async")]
     pub(super) async fn recv_columns_async(
         &mut self,
+        store: bool,
         columns: u64,
         cmd: &mut QueryCommand,
     ) -> Result<Vec<ColumnDefinition>>
     where
         Rt: sqlx_core::Async,
     {
-        impl_recv_columns!(columns, self, cmd)
-    }
-
-    #[cfg(feature = "async")]
-    pub(super) async fn recv_and_drop_columns_async(
-        &mut self,
-        columns: u64,
-        cmd: &mut QueryCommand,
-    ) -> Result<()>
-    where
-        Rt: sqlx_core::Async,
-    {
-        impl_recv_and_drop_columns!(columns, self, cmd)
+        impl_recv_columns!(store, columns, self, cmd)
     }
 
     #[cfg(feature = "blocking")]
     pub(crate) fn recv_columns_blocking(
         &mut self,
+        store: bool,
         columns: u64,
         cmd: &mut QueryCommand,
     ) -> Result<Vec<ColumnDefinition>>
     where
         Rt: sqlx_core::blocking::Runtime,
     {
-        impl_recv_columns!(@blocking columns, self, cmd)
-    }
-
-    #[cfg(feature = "blocking")]
-    pub(crate) fn recv_and_drop_columns_blocking(
-        &mut self,
-        columns: u64,
-        cmd: &mut QueryCommand,
-    ) -> Result<()>
-    where
-        Rt: sqlx_core::blocking::Runtime,
-    {
-        impl_recv_and_drop_columns!(@blocking columns, self, cmd)
+        impl_recv_columns!(@blocking store, columns, self, cmd)
     }
 }
 
 macro_rules! recv_columns {
-    (@blocking $columns:ident, $stream:ident, $cmd:ident) => {
-        $stream.recv_columns_blocking($columns, $cmd)?
+    (@blocking $store:expr, $columns:ident, $stream:ident, $cmd:ident) => {
+        $stream.recv_columns_blocking($store, $columns, $cmd)?
     };
 
-    ($columns:ident, $stream:ident, $cmd:ident) => {
-        $stream.recv_columns_async($columns, $cmd).await?
-    };
-}
-
-macro_rules! recv_and_drop_columns {
-    (@blocking $columns:ident, $stream:ident, $cmd:ident) => {
-        $stream.recv_and_drop_columns_blocking($columns, $cmd)?
-    };
-
-    ($columns:ident, $stream:ident, $cmd:ident) => {
-        $stream.recv_and_drop_columns_async($columns, $cmd).await?
+    ($store:expr, $columns:ident, $stream:ident, $cmd:ident) => {
+        $stream.recv_columns_async($store, $columns, $cmd).await?
     };
 }

sqlx-mysql/src/connection/executor/execute.rs

@@ -26,9 +26,8 @@ macro_rules! impl_execute {
                 match read_packet!($(@$blocking)? stream).deserialize_with(capabilities)? {
                     QueryResponse::Ok(ok) => break 'result ok,
                     QueryResponse::ResultSet { columns } => {
-                        // acknowledge but discard any columns
-                        // execute returns no rows
-                        recv_and_drop_columns!($(@$blocking)? columns, stream, cmd);
+                        // acknowledge but discard any columns as execute returns no rows
+                        recv_columns!($(@$blocking)? /* store = */ false, columns, stream, cmd);
 
                         'rows: loop {
                             match read_packet!($(@$blocking)? stream).deserialize_with((capabilities, &[][..]))? {