From feb22d43706e712ec91e4664c1867b6c2a160fc8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?K=C3=A9vin=20Commaille?= <zecakeh@tedomum.fr>
Date: Wed, 6 Aug 2025 15:19:30 +0200
Subject: [PATCH] Move serde functions to module and use `#[serde(with = "")]`
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>
---
 .../src/types/events/room/encrypted.rs        | 11 ++----
 .../src/types/events/room_key_request.rs      | 11 +-----
 crates/matrix-sdk-crypto/src/types/mod.rs     | 37 ++++++++++---------
 3 files changed, 24 insertions(+), 35 deletions(-)

diff --git a/crates/matrix-sdk-crypto/src/types/events/room/encrypted.rs b/crates/matrix-sdk-crypto/src/types/events/room/encrypted.rs
index 15e6ee367..79c0715c4 100644
--- a/crates/matrix-sdk-crypto/src/types/events/room/encrypted.rs
+++ b/crates/matrix-sdk-crypto/src/types/events/room/encrypted.rs
@@ -23,12 +23,12 @@ use vodozemac::{megolm::MegolmMessage, olm::OlmMessage, Curve25519PublicKey};
 
 use super::Event;
 use crate::types::{
-    deserialize_curve_key, deserialize_curve_key_option,
+    deserialize_curve_key,
     events::{
         room_key_request::{self, SupportedKeyInfo},
         EventType, ToDeviceEvent,
     },
-    serialize_curve_key, serialize_curve_key_option, EventEncryptionAlgorithm,
+    serde_curve_key_option, serialize_curve_key, EventEncryptionAlgorithm,
 };
 
 /// An m.room.encrypted room event.
@@ -309,12 +309,7 @@ pub struct MegolmV1AesSha2Content {
     pub ciphertext: MegolmMessage,
 
     /// The Curve25519 key of the sender.
-    #[serde(
-        default,
-        deserialize_with = "deserialize_curve_key_option",
-        serialize_with = "serialize_curve_key_option",
-        skip_serializing_if = "Option::is_none"
-    )]
+    #[serde(default, with = "serde_curve_key_option", skip_serializing_if = "Option::is_none")]
     pub sender_key: Option<Curve25519PublicKey>,
 
     /// The ID of the sending device.
diff --git a/crates/matrix-sdk-crypto/src/types/events/room_key_request.rs b/crates/matrix-sdk-crypto/src/types/events/room_key_request.rs
index c4ea191b8..a9ccdb07d 100644
--- a/crates/matrix-sdk-crypto/src/types/events/room_key_request.rs
+++ b/crates/matrix-sdk-crypto/src/types/events/room_key_request.rs
@@ -25,9 +25,7 @@ use serde_json::Value;
 use vodozemac::Curve25519PublicKey;
 
 use super::{EventType, ToDeviceEvent};
-use crate::types::{
-    deserialize_curve_key_option, serialize_curve_key_option, EventEncryptionAlgorithm,
-};
+use crate::types::{serde_curve_key_option, EventEncryptionAlgorithm};
 
 /// The `m.room_key_request` to-device event.
 pub type RoomKeyRequestEvent = ToDeviceEvent<RoomKeyRequestContent>;
@@ -211,12 +209,7 @@ pub struct MegolmV1AesSha2Content {
     pub room_id: OwnedRoomId,
 
     /// The Curve25519 key of the device which initiated the session originally.
-    #[serde(
-        default,
-        deserialize_with = "deserialize_curve_key_option",
-        serialize_with = "serialize_curve_key_option",
-        skip_serializing_if = "Option::is_none"
-    )]
+    #[serde(default, with = "serde_curve_key_option", skip_serializing_if = "Option::is_none")]
     pub sender_key: Option<Curve25519PublicKey>,
 
     /// The ID of the session that the key is for.
diff --git a/crates/matrix-sdk-crypto/src/types/mod.rs b/crates/matrix-sdk-crypto/src/types/mod.rs
index 2f78b709e..4c6032658 100644
--- a/crates/matrix-sdk-crypto/src/types/mod.rs
+++ b/crates/matrix-sdk-crypto/src/types/mod.rs
@@ -519,25 +519,26 @@ where
     keys.serialize(s)
 }
 
-pub(crate) fn deserialize_curve_key_option<'de, D>(
-    de: D,
-) -> Result<Option<Curve25519PublicKey>, D::Error>
-where
-    D: Deserializer<'de>,
-{
-    let key: Option<String> = Deserialize::deserialize(de)?;
-    key.map(|k| Curve25519PublicKey::from_base64(&k)).transpose().map_err(serde::de::Error::custom)
-}
+mod serde_curve_key_option {
+    use super::{Curve25519PublicKey, Deserialize, Deserializer, Serialize, Serializer};
 
-pub(crate) fn serialize_curve_key_option<S>(
-    key: &Option<Curve25519PublicKey>,
-    s: S,
-) -> Result<S::Ok, S::Error>
-where
-    S: Serializer,
-{
-    let key = key.as_ref().map(|k| k.to_base64());
-    key.serialize(s)
+    pub(crate) fn deserialize<'de, D>(de: D) -> Result<Option<Curve25519PublicKey>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let key: Option<String> = Deserialize::deserialize(de)?;
+        key.map(|k| Curve25519PublicKey::from_base64(&k))
+            .transpose()
+            .map_err(serde::de::Error::custom)
+    }
+
+    pub(crate) fn serialize<S>(key: &Option<Curve25519PublicKey>, s: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let key = key.as_ref().map(|k| k.to_base64());
+        key.serialize(s)
+    }
 }
 
 /// Trait to express the various room key export formats we have in a unified