feat: add secure weight charging for pop-api extension

runtime/src/extensions/pop_api_extension.rs

@@ -60,26 +60,24 @@ where
 {
     let mut env = env.buf_in_buf_out();
 
-    // charge max weight before reading contract memory
-    // TODO: causing "1010: block limits exhausted" error
-    // let weight_limit = env.ext().gas_meter().gas_left();
-    // let charged_weight = env.charge_weight(weight_limit)?;
-
-    // TODO: debug_message weight is a good approximation of the additional overhead of going
-    // from contract layer to substrate layer.
-
     // input length
     let len = env.in_len();
     let call: <T as SysConfig>::RuntimeCall = env.read_as_unbounded(len)?;
 
+    // conservative weight estimate for deserializing the input. The actual weight is less and should utilize a custom benchmark
+    let base_weight: Weight = T::DbWeight::get().reads(len.into());
+
+    // weight for dispatching the call
+    let dispatch_weight = call.get_dispatch_info().weight;
+
+    // charge weight for the cost of the deserialization and the dispatch
+    let _ = env.charge_weight(base_weight.saturating_add(dispatch_weight))?;
+
     log::debug!(target:LOG_TARGET, " dispatch inputted RuntimeCall: {:?}", call);
 
     let sender = env.ext().caller();
     let origin: T::RuntimeOrigin = RawOrigin::Signed(sender.account_id()?.clone()).into();
 
-    // TODO: uncomment once charged_weight is fixed
-    // let actual_weight = call.get_dispatch_info().weight;
-    // env.adjust_weight(charged_weight, actual_weight);
     let result = call.dispatch(origin);
     match result {
         Ok(info) => {