secret: Store secret in MessagePack format

Should be more compact and efficient

Cargo.lock

@@ -1315,6 +1315,7 @@ dependencies = [
  "qrcode",
  "rand 0.8.5",
  "regex",
+ "rmp-serde",
  "rqrr",
  "ruma",
  "secular",

Cargo.toml

@@ -55,6 +55,7 @@ pulldown-cmark = "0.9"
 qrcode = "0.12"
 rand = "0.8"
 regex = "1"
+rmp-serde = "1"
 rqrr = "0.6"
 secular = { version = "1", features = ["bmp", "normalization"] }
 serde = "1"

src/secret.rs

@@ -230,7 +230,9 @@ impl StoredSession {
             }
         };
         let secret = match item.secret().await {
-            Ok(secret) => match Secret::from_utf8(&secret) {
+            Ok(secret) => {
+                if version == 0 {
+                    match Secret::from_utf8(&secret) {
                         Ok(secret) => secret,
                         Err(error) => {
                             error!("Could not parse secret in stored session: {error:?}");
@@ -239,7 +241,20 @@ impl StoredSession {
                                 item,
                             });
                         }
-            },
+                    }
+                } else {
+                    match rmp_serde::from_slice::<Secret>(&secret) {
+                        Ok(secret) => secret,
+                        Err(error) => {
+                            error!("Could not parse secret in stored session: {error}");
+                            return Err(SecretError::CorruptSession {
+                                error: gettext("Malformed secret in stored session"),
+                                item,
+                            });
+                        }
+                    }
+                }
+            }
             Err(error) => {
                 error!("Could not get secret in stored session: {error}");
                 return Err(SecretError::CorruptSession {
@@ -347,7 +362,7 @@ pub async fn store_session(session: &StoredSession) -> Result<(), SecretError> {
 
     let attrs = session.attributes();
     let attributes = attrs.iter().map(|(k, v)| (*k, v.as_ref())).collect();
-    let secret = serde_json::to_string(&session.secret).unwrap();
+    let secret = rmp_serde::to_vec_named(&session.secret).unwrap();
 
     keyring
         .create_item(