Improve calls table with FOREIGN KEY, STRICT mode, and better housekeeping query

Co-authored-by: link2xt <18373967+link2xt@users.noreply.github.com>

src/calls.rs

@@ -509,7 +509,10 @@ impl Context {
 
     // Loads information about the call given the `Message`.
     //
-    // If the `Message` is not a call message, returns `None`
+    // If the `Message` is not a call message, returns `None`.
+    //
+    // This function is async because it queries the calls table
+    // to retrieve SDP offers and answers.
     async fn load_call_by_message(&self, call: Message) -> Result<Option<CallInfo>> {
         if call.viewtype != Viewtype::Call {
             // This can happen e.g. if a "call accepted"

src/sql.rs

@@ -922,17 +922,18 @@ pub async fn housekeeping(context: &Context) -> Result<()> {
         .ok();
 
     // Delete call SDPs for ended calls (older than 24 hours) or orphaned calls.
-    // Ended calls have Param::Arg4 (H=timestamp) set in their params.
     // We clean up calls that ended more than 24 hours ago to protect privacy
-    // as SDPs contain IP addresses.
+    // as SDPs contain IP addresses. Ended calls are identified by having
+    // the CALL_ENDED_TIMESTAMP parameter (Param::Arg4) set.
+    // The ON DELETE CASCADE foreign key will handle orphaned entries automatically,
+    // but we also check for trash and old ended calls.
     context
         .sql
         .execute(
             "DELETE FROM calls WHERE msg_id IN (
                 SELECT calls.msg_id FROM calls 
-                LEFT JOIN msgs ON calls.msg_id = msgs.id
+                INNER JOIN msgs ON calls.msg_id = msgs.id
-                WHERE msgs.id IS NULL
+                WHERE msgs.chat_id = ?
-                   OR msgs.chat_id = ?
                    OR (msgs.param LIKE '%H=%'
                        AND msgs.timestamp_sent < ?)
             )",

src/sql/migrations.rs

@@ -1344,10 +1344,10 @@ CREATE INDEX gossip_timestamp_index ON gossip_timestamp (chat_id, fingerprint);
         sql.execute_migration(
             "CREATE TABLE calls(
                 id INTEGER PRIMARY KEY AUTOINCREMENT,
-                msg_id INTEGER NOT NULL UNIQUE,
+                msg_id INTEGER NOT NULL UNIQUE REFERENCES msgs(id) ON DELETE CASCADE,
                 offer_sdp TEXT,
                 answer_sdp TEXT
-            );
+            ) STRICT;
             CREATE INDEX calls_msg_id_index ON calls (msg_id);",
             migration_version,
         )