events: Provide type for historical m.message content block instead of serde helper

crates/ruma-common/src/events/message/historical_serde.rs

@@ -6,6 +6,24 @@ use serde::{Deserialize, Serialize};
 
 use super::{TextContentBlock, TextRepresentation};
 
+/// Historical `m.message` text content block from MSC1767.
+#[derive(Clone, Default, Serialize, Deserialize)]
+#[serde(try_from = "MessageContentBlockSerDeHelper")]
+#[serde(into = "MessageContentBlockSerDeHelper")]
+pub(in crate::events) struct MessageContentBlock(Vec<TextRepresentation>);
+
+impl From<MessageContentBlock> for TextContentBlock {
+    fn from(value: MessageContentBlock) -> Self {
+        Self(value.0)
+    }
+}
+
+impl From<TextContentBlock> for MessageContentBlock {
+    fn from(value: TextContentBlock) -> Self {
+        Self(value.0)
+    }
+}
+
 #[derive(Default, Serialize, Deserialize)]
 pub(in crate::events) struct MessageContentBlockSerDeHelper {
     /// Plain text short form.
@@ -21,14 +39,14 @@ pub(in crate::events) struct MessageContentBlockSerDeHelper {
     message: Option<Vec<TextRepresentation>>,
 }
 
-impl TryFrom<MessageContentBlockSerDeHelper> for TextContentBlock {
+impl TryFrom<MessageContentBlockSerDeHelper> for Vec<TextRepresentation> {
     type Error = &'static str;
 
     fn try_from(value: MessageContentBlockSerDeHelper) -> Result<Self, Self::Error> {
         let MessageContentBlockSerDeHelper { text, html, message } = value;
 
         if let Some(message) = message {
-            Ok(Self(message))
+            Ok(message)
         } else {
             let message: Vec<_> = html
                 .map(TextRepresentation::html)
@@ -36,7 +54,7 @@ impl TryFrom<MessageContentBlockSerDeHelper> for TextContentBlock {
                 .chain(text.map(TextRepresentation::plain))
                 .collect();
             if !message.is_empty() {
-                Ok(Self(message))
+                Ok(message)
             } else {
                 Err("missing at least one of fields `org.matrix.msc1767.text`, `org.matrix.msc1767.html` or `org.matrix.msc1767.message`")
             }
@@ -44,15 +62,23 @@ impl TryFrom<MessageContentBlockSerDeHelper> for TextContentBlock {
     }
 }
 
-impl From<TextContentBlock> for MessageContentBlockSerDeHelper {
-    fn from(value: TextContentBlock) -> Self {
+impl TryFrom<MessageContentBlockSerDeHelper> for MessageContentBlock {
+    type Error = &'static str;
+
+    fn try_from(value: MessageContentBlockSerDeHelper) -> Result<Self, Self::Error> {
+        Ok(Self(value.try_into()?))
+    }
+}
+
+impl From<Vec<TextRepresentation>> for MessageContentBlockSerDeHelper {
+    fn from(value: Vec<TextRepresentation>) -> Self {
         let has_shortcut =
             |message: &TextRepresentation| matches!(&*message.mimetype, "text/plain" | "text/html");
 
         if value.iter().all(has_shortcut) {
             let mut helper = Self::default();
 
-            for message in value.0.into_iter() {
+            for message in value.into_iter() {
                 if message.mimetype == "text/plain" {
                     helper.text = Some(message.body);
                 } else if message.mimetype == "text/html" {
@@ -62,7 +88,13 @@ impl From<TextContentBlock> for MessageContentBlockSerDeHelper {
 
             helper
         } else {
-            Self { message: Some(value.0), ..Default::default() }
+            Self { message: Some(value), ..Default::default() }
         }
     }
 }
+
+impl From<MessageContentBlock> for MessageContentBlockSerDeHelper {
+    fn from(value: MessageContentBlock) -> Self {
+        value.0.into()
+    }
+}

crates/ruma-common/src/events/room/message/content_serde.rs

@@ -83,7 +83,7 @@ pub(in super::super) mod msc3488 {
     use crate::{
         events::{
             location::{AssetContent, LocationContent},
-            message::historical_serde::MessageContentBlockSerDeHelper,
+            message::historical_serde::MessageContentBlock,
             room::message::{LocationInfo, LocationMessageEventContent},
         },
         MilliSecondsSinceUnixEpoch,
@@ -101,7 +101,7 @@ pub(in super::super) mod msc3488 {
         pub info: Option<Box<LocationInfo>>,
 
         #[serde(flatten)]
-        pub message: MessageContentBlockSerDeHelper,
+        pub message: Option<MessageContentBlock>,
 
         #[serde(rename = "org.matrix.msc3488.location", skip_serializing_if = "Option::is_none")]
         pub location: Option<LocationContent>,
@@ -118,15 +118,7 @@ pub(in super::super) mod msc3488 {
             let LocationMessageEventContent { body, geo_uri, info, message, location, asset, ts } =
                 value;
 
-            Self {
-                body,
-                geo_uri,
-                info,
-                message: message.map(Into::into).unwrap_or_default(),
-                location,
-                asset,
-                ts,
-            }
+            Self { body, geo_uri, info, message: message.map(Into::into), location, asset, ts }
         }
     }
 
@@ -146,7 +138,7 @@ pub(in super::super) mod msc3488 {
                 body,
                 geo_uri,
                 info,
-                message: message.try_into().ok(),
+                message: message.map(Into::into),
                 location,
                 asset,
                 ts,