Batch aggregation framework

src/coprocessor/codec/data_type/mod.rs

@@ -15,7 +15,7 @@ pub use crate::coprocessor::codec::mysql::{Decimal, Duration, Json, Time as Date
 
 // Dynamic eval types.
 pub use self::scalar::ScalarValue;
-pub use self::vector::VectorValue;
+pub use self::vector::{VectorValue, VectorValueExt};
 pub use self::vector_like::{VectorLikeValueRef, VectorLikeValueRefSpecialized};
 
 use crate::coprocessor::dag::expr::EvalContext;

src/coprocessor/codec/data_type/vector.rs

@@ -650,7 +650,20 @@ macro_rules! impl_as_slice {
             }
         }
 
-        // `AsMut` is not implemented intentionally.
+        // TODO: We should only expose interface for push value, not the entire Vec.
+        impl AsMut<Vec<Option<$ty>>> for VectorValue {
+            #[inline]
+            fn as_mut(&mut self) -> &mut Vec<Option<$ty>> {
+                match self {
+                    VectorValue::$ty(ref mut vec) => vec,
+                    other => panic!(
+                        "Cannot retrieve a mutable `{}` vector over a {} column",
+                        stringify!($ty),
+                        other.eval_type()
+                    ),
+                }
+            }
+        }
     };
 }
 
@@ -662,16 +675,22 @@ impl_as_slice! { DateTime, as_date_time_slice }
 impl_as_slice! { Duration, as_duration_slice }
 impl_as_slice! { Json, as_json_slice }
 
-macro_rules! impl_push {
-    ($ty:tt, $name:ident) => {
+pub trait VectorValueExt<T: Evaluable> {
+    fn push(&mut self, v: Option<T>);
+}
+
+macro_rules! impl_ext {
+    ($ty:tt, $push_name:ident) => {
+        // Explicit version
+
         impl VectorValue {
             /// Pushes a value in specified concrete type into current column.
             ///
             /// # Panics
             ///
             /// Panics if the current column does not match the type.
             #[inline]
-            pub fn $name(&mut self, v: Option<$ty>) {
+            pub fn $push_name(&mut self, v: Option<$ty>) {
                 match self {
                     VectorValue::$ty(ref mut vec) => vec.push(v),
                     other => panic!(
@@ -682,16 +701,25 @@ macro_rules! impl_push {
                 };
             }
         }
+
+        // Implicit version
+
+        impl VectorValueExt<$ty> for VectorValue {
+            #[inline]
+            fn push(&mut self, v: Option<$ty>) {
+                self.$push_name(v);
+            }
+        }
     };
 }
 
-impl_push! { Int, push_int }
-impl_push! { Real, push_real }
-impl_push! { Decimal, push_decimal }
-impl_push! { Bytes, push_bytes }
-impl_push! { DateTime, push_date_time }
-impl_push! { Duration, push_duration }
-impl_push! { Json, push_json }
+impl_ext! { Int, push_int }
+impl_ext! { Real, push_real }
+impl_ext! { Decimal, push_decimal }
+impl_ext! { Bytes, push_bytes }
+impl_ext! { DateTime, push_date_time }
+impl_ext! { Duration, push_duration }
+impl_ext! { Json, push_json }
 
 macro_rules! impl_from {
     ($ty:tt) => {