wallet: delete_{invoice,request}: add "write_to_disk=True" param

to support faster batch-deletion

electrum/gui/qt/invoice_list.py

@@ -194,5 +194,6 @@ class InvoiceList(MyTreeView):
 
     def delete_invoices(self, keys):
         for key in keys:
-            self.wallet.delete_invoice(key)
+            self.wallet.delete_invoice(key, write_to_disk=False)
             self.delete_item(key)
+        self.wallet.save_db()

electrum/gui/qt/request_list.py

@@ -192,6 +192,7 @@ class RequestList(MyTreeView):
 
     def delete_requests(self, keys):
         for key in keys:
-            self.wallet.delete_request(key)
+            self.wallet.delete_request(key, write_to_disk=False)
             self.delete_item(key)
+        self.wallet.save_db()
         self.receive_tab.do_clear()

electrum/wallet.py

@@ -2517,7 +2517,7 @@ class Abstract_Wallet(ABC, Logger, EventListener):
             self.save_db()
         return key
 
-    def delete_request(self, key):
+    def delete_request(self, key, *, write_to_disk: bool = True):
         """ lightning or on-chain """
         req = self._receive_requests.pop(key, None)
         if req is None:
@@ -2526,16 +2526,18 @@ class Abstract_Wallet(ABC, Logger, EventListener):
             self._requests_addr_to_rhash.pop(addr)
         if req.is_lightning() and self.lnworker:
             self.lnworker.delete_payment_info(req.rhash)
-        self.save_db()
+        if write_to_disk:
+            self.save_db()
 
-    def delete_invoice(self, key):
+    def delete_invoice(self, key, *, write_to_disk: bool = True):
         """ lightning or on-chain """
         inv = self._invoices.pop(key, None)
         if inv is None:
             return
         if inv.is_lightning() and self.lnworker:
             self.lnworker.delete_payment_info(inv.rhash)
-        self.save_db()
+        if write_to_disk:
+            self.save_db()
 
     def get_sorted_requests(self) -> List[Invoice]:
         """ sorted by timestamp """