Add sync_changes to CalendarStore

crates/store/src/calendar.rs

@@ -13,3 +13,23 @@ pub struct Calendar {
     pub deleted_at: Option<NaiveDateTime>,
     pub synctoken: i64,
 }
+
+impl Calendar {
+    pub fn format_synctoken(&self) -> String {
+        format_synctoken(self.synctoken)
+    }
+}
+
+const SYNC_NAMESPACE: &str = "github.com/lennart-k/rustical/ns/";
+
+pub fn format_synctoken(synctoken: i64) -> String {
+    format!("{}{}", SYNC_NAMESPACE, synctoken)
+}
+
+pub fn parse_synctoken(synctoken: &str) -> Option<i64> {
+    if !synctoken.starts_with(SYNC_NAMESPACE) {
+        return None;
+    }
+    let (_, synctoken) = synctoken.split_at(SYNC_NAMESPACE.len());
+    synctoken.parse::<i64>().ok()
+}

crates/store/src/sqlite_store.rs

@@ -32,7 +32,7 @@ impl TryFrom<EventRow> for Event {
     }
 }
 
-#[derive(Serialize, sqlx::Type)]
+#[derive(Debug, Clone, Serialize, sqlx::Type)]
 #[serde(rename_all = "kebab-case")]
 enum CalendarChangeOperation {
     // There's no distinction between Add and Modify
@@ -308,6 +308,47 @@ impl CalendarStore for SqliteCalendarStore {
         tx.commit().await?;
         Ok(())
     }
+
+    async fn sync_changes(
+        &self,
+        principal: &str,
+        cid: &str,
+        synctoken: i64,
+    ) -> Result<(Vec<Event>, Vec<String>, i64), Error> {
+        struct Row {
+            uid: String,
+            synctoken: i64,
+        }
+        let changes = sqlx::query_as!(
+            Row,
+            r#"
+                SELECT DISTINCT uid, max(0, synctoken) as "synctoken!: i64" from eventchangelog
+                WHERE synctoken > ?
+                ORDER BY synctoken ASC
+            "#,
+            synctoken
+        )
+        .fetch_all(&self.db)
+        .await?;
+
+        let mut events = vec![];
+        let mut deleted_events = vec![];
+
+        let new_synctoken = changes
+            .last()
+            .map(|&Row { synctoken, .. }| synctoken)
+            .unwrap_or(0);
+
+        for Row { uid, .. } in changes {
+            match self.get_event(principal, cid, &uid).await {
+                Ok(event) => events.push(event),
+                Err(Error::NotFound) => deleted_events.push(uid),
+                Err(err) => return Err(err),
+            }
+        }
+
+        Ok((events, deleted_events, new_synctoken))
+    }
 }
 
 pub async fn create_db_pool(db_url: &str, migrate: bool) -> anyhow::Result<Pool<Sqlite>> {

crates/store/src/store.rs

@@ -24,6 +24,13 @@ pub trait CalendarStore: Send + Sync + 'static {
     ) -> Result<(), Error>;
     async fn restore_calendar(&mut self, principal: &str, name: &str) -> Result<(), Error>;
 
+    async fn sync_changes(
+        &self,
+        principal: &str,
+        cid: &str,
+        synctoken: i64,
+    ) -> Result<(Vec<Event>, Vec<String>, i64), Error>;
+
     async fn get_events(&self, principal: &str, cid: &str) -> Result<Vec<Event>, Error>;
     async fn get_event(&self, principal: &str, cid: &str, uid: &str) -> Result<Event, Error>;
     async fn put_event(