Store type name of a field in event metadata (#654)

subxt/src/events/events_type.rs

@@ -187,11 +187,11 @@ impl EventDetails {
         );
 
         // Skip over the bytes belonging to this event.
-        for (_name, type_id) in event_metadata.fields() {
+        for field_metadata in event_metadata.fields() {
             // Skip over the bytes for this field:
             scale_decode::decode(
                 input,
-                *type_id,
+                field_metadata.type_id(),
                 &metadata.runtime_metadata().types,
                 scale_decode::visitor::IgnoreVisitor,
             )?;
@@ -288,15 +288,15 @@ impl EventDetails {
         let is_named = event_metadata
             .fields()
             .get(0)
-            .map(|(n, _)| n.is_some())
+            .map(|fm| fm.name().is_some())
             .unwrap_or(false);
 
         if !is_named {
             let mut event_values = vec![];
-            for (_, type_id) in event_metadata.fields() {
+            for field_metadata in event_metadata.fields() {
                 let value = scale_value::scale::decode_as_type(
                     bytes,
-                    *type_id,
+                    field_metadata.type_id(),
                     &self.metadata.runtime_metadata().types,
                 )?;
                 event_values.push(value);
@@ -305,13 +305,14 @@ impl EventDetails {
             Ok(scale_value::Composite::Unnamed(event_values))
         } else {
             let mut event_values = vec![];
-            for (name, type_id) in event_metadata.fields() {
+            for field_metadata in event_metadata.fields() {
                 let value = scale_value::scale::decode_as_type(
                     bytes,
-                    *type_id,
+                    field_metadata.type_id(),
                     &self.metadata.runtime_metadata().types,
                 )?;
-                event_values.push((name.clone().unwrap_or_default(), value));
+                event_values
+                    .push((field_metadata.name().unwrap_or_default().to_string(), value));
             }
 
             Ok(scale_value::Composite::Named(event_values))

subxt/src/metadata/metadata_type.rs

@@ -297,6 +297,39 @@ impl PalletMetadata {
     }
 }
 
+/// Metadata for specific field.
+#[derive(Clone, Debug)]
+pub struct EventFieldMetadata {
+    name: Option<String>,
+    type_name: Option<String>,
+    type_id: u32,
+}
+
+impl EventFieldMetadata {
+    pub fn new(name: Option<String>, type_name: Option<String>, type_id: u32) -> Self {
+        EventFieldMetadata {
+            name,
+            type_name,
+            type_id,
+        }
+    }
+
+    /// Get the name of the field.
+    pub fn name(&self) -> Option<&str> {
+        self.name.as_deref()
+    }
+
+    // Get the type name of the field as it appears in the code
+    pub fn type_name(&self) -> Option<&str> {
+        self.type_name.as_deref()
+    }
+
+    /// Get the id of a type
+    pub fn type_id(&self) -> u32 {
+        self.type_id
+    }
+}
+
 /// Metadata for specific events.
 #[derive(Clone, Debug)]
 pub struct EventMetadata {
@@ -304,7 +337,7 @@ pub struct EventMetadata {
     // behind an Arc to avoid lots of needless clones of it existing.
     pallet: Arc<str>,
     event: String,
-    fields: Vec<(Option<String>, u32)>,
+    fields: Vec<EventFieldMetadata>,
     docs: Vec<String>,
 }
 
@@ -319,8 +352,8 @@ impl EventMetadata {
         &self.event
     }
 
-    /// The names and types of each field in the event.
-    pub fn fields(&self) -> &[(Option<String>, u32)] {
+    /// The names, type names & types of each field in the event.
+    pub fn fields(&self) -> &[EventFieldMetadata] {
         &self.fields
     }
 
@@ -457,7 +490,13 @@ impl TryFrom<RuntimeMetadataPrefixed> for Metadata {
                             fields: variant
                                 .fields()
                                 .iter()
-                                .map(|f| (f.name().map(|n| n.to_owned()), f.ty().id()))
+                                .map(|f| {
+                                    EventFieldMetadata::new(
+                                        f.name().map(|n| n.to_owned()),
+                                        f.type_name().map(|n| n.to_owned()),
+                                        f.ty().id(),
+                                    )
+                                })
                                 .collect(),
                             docs: variant.docs().to_vec(),
                         },