Implement json metadata for outer events

Progress on: #535

substrate/runtime-support/Cargo.toml

@@ -16,6 +16,7 @@ substrate-codec = { path = "../codec", default_features = false }
 [dev-dependencies]
 pretty_assertions = "0.5.1"
 serde_json = { version = "1.0" }
+substrate-codec-derive = { path = "../../substrate/codec/derive" }
 
 [features]
 default = ["std"]

substrate/runtime-support/src/event.rs

@@ -0,0 +1,99 @@
+#[macro_export]
+macro_rules! impl_outer_event {
+	($(#[$attr:meta])* pub enum $name:ident for $runtime:ident { $( $module:ident ),* }) => {
+		// Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
+		#[derive(Clone, PartialEq, Eq, Encode, Decode)]
+		#[cfg_attr(feature = "std", derive(Debug, Serialize, Deserialize))]
+		$(#[$attr])*
+		#[allow(non_camel_case_types)]
+		pub enum $name {
+			system(system::Event),
+			$(
+				$module($module::Event<$runtime>),
+			)*
+		}
+		impl From<system::Event> for $name {
+			fn from(x: system::Event) -> Self {
+				$name::system(x)
+			}
+		}
+		$(
+			impl From<$module::Event<$runtime>> for $name {
+				fn from(x: $module::Event<$runtime>) -> Self {
+					$name::$module(x)
+				}
+			}
+		)*
+		__impl_outer_event_json_metadata!($runtime; $name; $( $module )*);
+	}
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! __impl_outer_event_json_metadata {
+	(
+		$runtime:ident;
+		$event_name:ident;
+		$( $module:ident )*
+	) => {
+		impl $runtime {
+			pub fn outer_event_json_metadata() -> &'static str {
+				concat!(r#"{ "name": ""#, stringify!($event_name), r#"", "items": { "#,
+					r#""system": "system::Event""#,
+					$(concat!(", \"", stringify!($module), r#"": ""#, 
+						stringify!($module), "::Event<", stringify!($runtime), r#">""#),)*
+					" } }")
+			}
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use serde;
+	use serde_json;
+
+	mod system {
+		#[derive(Debug, Clone, PartialEq, Eq, Encode, Decode, Deserialize, Serialize)]
+		pub struct Event;
+	}
+
+	mod event_module {
+		#[derive(Debug, Clone, PartialEq, Eq, Encode, Decode, Deserialize, Serialize)]
+		pub struct Event<T> {
+			t: T,
+		}
+	}
+
+	mod event_module2 {
+		#[derive(Debug, Clone, PartialEq, Eq, Encode, Decode, Deserialize, Serialize)]
+		pub struct Event<T> {
+			t: T,
+		}
+	}
+
+	#[derive(Debug, Clone, PartialEq, Eq, Encode, Decode, Deserialize, Serialize)]
+	pub struct TestRuntime;
+
+	impl_outer_event! {
+		pub enum TestEvent for TestRuntime {
+			event_module, event_module2
+		}
+	}
+
+	const EXPECTED_METADATA: &str = concat!(
+		r#"{ "name": "TestEvent", "items": { "#,
+			r#""system": "system::Event", "#,
+			r#""event_module": "event_module::Event<TestRuntime>", "#,
+			r#""event_module2": "event_module2::Event<TestRuntime>" "#,
+		r#"} }"#
+	);
+
+	#[test]
+	fn outer_event_json_metadata() {
+		let metadata = TestRuntime::outer_event_json_metadata();
+		assert_eq!(EXPECTED_METADATA, metadata);
+		let _: serde::de::IgnoredAny =
+			serde_json::from_str(metadata).expect("Is valid json syntax");
+	}
+}

substrate/runtime-support/src/lib.rs

@@ -33,6 +33,9 @@ extern crate pretty_assertions;
 extern crate serde_derive;
 #[cfg(test)]
 extern crate serde_json;
+#[cfg(test)]
+#[macro_use]
+extern crate substrate_codec_derive;
 
 #[doc(hidden)]
 pub extern crate substrate_codec as codec;
@@ -42,6 +45,8 @@ pub use self::storage::generator::Storage as GenericStorage;
 pub mod dispatch;
 pub mod storage;
 mod hashable;
+#[macro_use]
+mod event;
 
 pub use self::storage::{StorageVec, StorageList, StorageValue, StorageMap};
 pub use self::hashable::Hashable;
@@ -94,35 +99,6 @@ macro_rules! assert_ok {
 	}
 }
 
-#[macro_export]
-macro_rules! impl_outer_event {
-	($(#[$attr:meta])* pub enum $name:ident for $trait:ident { $( $module:ident ),* }) => {
-		// Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
-		#[derive(Clone, PartialEq, Eq, Encode, Decode)]
-		#[cfg_attr(feature = "std", derive(Debug, Serialize, Deserialize))]
-		$(#[$attr])*
-		#[allow(non_camel_case_types)]
-		pub enum $name {
-			system(system::Event),
-			$(
-				$module($module::Event<$trait>),
-			)*
-		}
-		impl From<system::Event> for $name {
-			fn from(x: system::Event) -> Self {
-				$name::system(x)
-			}
-		}
-		$(
-			impl From<$module::Event<$trait>> for $name {
-				fn from(x: $module::Event<$trait>) -> Self {
-					$name::$module(x)
-				}
-			}
-		)*
-	}
-}
-
 #[macro_export]
 macro_rules! impl_outer_log {