close nostrdb and disconnect from relays on logout

This was causing crashing and corruption issues. This should have been
handled by the garbage collector, but for some reason old references
still hang around.

Add a "close" method to DamusState which disconnects from relays and
closes nostrdb.

Changelog-Fixed: Fix crash when logging out and switching accounts
Changelog-Fixed: Fix persistent local notifications even after logout
Signed-off-by: William Casarin <jb55@jb55.com>

damus/ContentView.swift

@@ -624,7 +624,7 @@ struct ContentView: View {
 
             // out of space or something?? maybe we need a in-memory fallback
             if mndb == nil {
-                notify(.logout)
+                logout(nil)
                 return
             }
         }
@@ -1082,3 +1082,10 @@ func on_open_url(state: DamusState, url: URL, result: @escaping (OpenResult?) ->
     }
 }
 
+
+func logout(_ state: DamusState?)
+{
+    state?.close()
+    notify(.logout)
+}
+

damus/Models/DamusState.swift

@@ -92,7 +92,12 @@ struct DamusState: HeadlessDamusState {
     var is_privkey_user: Bool {
         keypair.privkey != nil
     }
-    
+
+    func close() {
+        pool.close()
+        ndb.close()
+    }
+
     static var empty: DamusState {
         let empty_pub: Pubkey = .empty
         let empty_sec: Privkey = .empty

damus/Nostr/RelayPool.swift

@@ -39,6 +39,16 @@ class RelayPool {
     private let network_monitor_queue = DispatchQueue(label: "io.damus.network_monitor")
     private var last_network_status: NWPath.Status = .unsatisfied
 
+    func close() {
+        disconnect()
+        relays = []
+        handlers = []
+        request_queue = []
+        seen.removeAll()
+        counts = [:]
+        keypair = nil
+    }
+
     init(ndb: Ndb, keypair: Keypair? = nil) {
         self.ndb = ndb
         self.keypair = keypair

damus/Views/ConfigView.swift

@@ -72,7 +72,7 @@ struct ConfigView: View {
                 Section(NSLocalizedString("Sign Out", comment: "Section title for signing out")) {
                     Button(action: {
                         if state.keypair.privkey == nil {
-                            notify(.logout)
+                            logout(state)
                         } else {
                             confirm_logout = true
                         }
@@ -130,7 +130,7 @@ struct ConfigView: View {
                     return
                 }
                 state.postbox.send(ev)
-                notify(.logout)
+                logout(state)
             }
         }
         .alert(NSLocalizedString("Logout", comment: "Alert for logging out the user."), isPresented: $confirm_logout) {
@@ -138,7 +138,7 @@ struct ConfigView: View {
                 confirm_logout = false
             }
             Button(NSLocalizedString("Logout", comment: "Button for logging out the user."), role: .destructive) {
-                notify(.logout)
+                logout(state)
             }
         } message: {
                 Text("Make sure your nsec account key is saved before you logout or you will lose access to this account", comment: "Reminder message in alert to get customer to verify that their private security account key is saved saved before logging out.")

damus/Views/SideMenuView.swift

@@ -164,7 +164,7 @@ struct SideMenuView: View {
                         Button(action: {
                             //ConfigView(state: damus_state)
                             if damus_state.keypair.privkey == nil {
-                                notify(.logout)
+                                logout(damus_state)
                             } else {
                                 confirm_logout = true
                             }
@@ -202,7 +202,7 @@ struct SideMenuView: View {
                     confirm_logout = false
                 }
                 Button(NSLocalizedString("Logout", comment: "Button for logging out the user."), role: .destructive) {
-                    notify(.logout)
+                    logout(damus_state)
                 }
             } message: {
                 Text("Make sure your nsec account key is saved before you logout or you will lose access to this account", comment: "Reminder message in alert to get customer to verify that their private security account key is saved saved before logging out.")

nostrdb/Ndb.swift

@@ -176,6 +176,7 @@ class Ndb {
     }
     
     func close() {
+        guard !self.closed else { return }
         self.closed = true
         ndb_destroy(self.ndb.ndb)
     }