implement dispatch_as (#9934)

* implement dispatch_as

* fix

* fix

* weight for dispatch_as

* cargo run --quiet --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_utility --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/utility/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* fix

* Update frame/utility/src/benchmarking.rs

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* fix issues

Co-authored-by: Parity Bot <admin@parity.io>
Co-authored-by: Alexander Theißen <alex.theissen@me.com>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>

substrate/frame/utility/src/lib.rs

@@ -96,6 +96,11 @@ pub mod pallet {
 			+ IsSubType<Call<Self>>
 			+ IsType<<Self as frame_system::Config>::Call>;
 
+		/// The caller origin, overarching type of all pallets origins.
+		type PalletsOrigin: Parameter +
+			Into<<Self as frame_system::Config>::Origin> +
+			IsType<<<Self as frame_system::Config>::Origin as frame_support::traits::OriginTrait>::PalletsOrigin>;
+
 		/// Weight information for extrinsics in this pallet.
 		type WeightInfo: WeightInfo;
 	}
@@ -110,6 +115,8 @@ pub mod pallet {
 		BatchCompleted,
 		/// A single item within a Batch of dispatches has completed with no error.
 		ItemCompleted,
+		/// A call was dispatched. \[result\]
+		DispatchedAs(DispatchResult),
 	}
 
 	// Align the call size to 1KB. As we are currently compiling the runtime for native/wasm
@@ -342,6 +349,37 @@ pub mod pallet {
 			let base_weight = T::WeightInfo::batch_all(calls_len as u32);
 			Ok(Some(base_weight + weight).into())
 		}
+
+		/// Dispatches a function call with a provided origin.
+		///
+		/// The dispatch origin for this call must be _Root_.
+		///
+		/// # <weight>
+		/// - O(1).
+		/// - Limited storage reads.
+		/// - One DB write (event).
+		/// - Weight of derivative `call` execution + T::WeightInfo::dispatch_as().
+		/// # </weight>
+		#[pallet::weight({
+			let dispatch_info = call.get_dispatch_info();
+			(
+				T::WeightInfo::dispatch_as()
+					.saturating_add(dispatch_info.weight),
+				dispatch_info.class,
+			)
+		})]
+		pub fn dispatch_as(
+			origin: OriginFor<T>,
+			as_origin: Box<T::PalletsOrigin>,
+			call: Box<<T as Config>::Call>,
+		) -> DispatchResult {
+			ensure_root(origin)?;
+
+			let res = call.dispatch_bypass_filter((*as_origin).into());
+
+			Self::deposit_event(Event::DispatchedAs(res.map(|_| ()).map_err(|e| e.error)));
+			Ok(())
+		}
 	}
 }