Fix read lock overlap with mempool RwLock

See #57

Author: junderw

src/elements/asset.rs

@@ -363,7 +363,8 @@ pub fn lookup_asset(
     }
 
     let history_db = query.chain().store().history_db();
-    let mempool_issuances = &query.mempool().asset_issuance;
+    let mempool = query.mempool();
+    let mempool_issuances = &mempool.asset_issuance;
 
     let chain_row = history_db
         .get(&[b"i", &asset_id.into_inner()[..]].concat())
@@ -380,7 +381,7 @@ pub fn lookup_asset(
         let meta = meta
             .or_else(|| registry.as_ref().and_then(|r| r.get(asset_id)))
             .cloned();
-        let stats = issued_asset_stats(query, asset_id, &reissuance_token);
+        let stats = issued_asset_stats(query.chain(), &mempool, asset_id, &reissuance_token);
         let status = query.get_tx_status(&deserialize(&row.issuance_txid).unwrap());
 
         let asset = IssuedAsset::new(asset_id, row, stats, meta, status);
@@ -460,21 +461,20 @@ fn pegged_asset_stats(query: &Query, asset_id: &AssetId) -> (PeggedAssetStats, P
 
 // Get stats for issued assets
 fn issued_asset_stats(
-    query: &Query,
+    chain: &ChainQuery,
+    mempool: &Mempool,
     asset_id: &AssetId,
     reissuance_token: &AssetId,
 ) -> (IssuedAssetStats, IssuedAssetStats) {
     let afn = apply_issued_asset_stats;
 
-    let chain = query.chain();
     let mut chain_stats = chain_asset_stats(chain, asset_id, afn);
     chain_stats.burned_reissuance_tokens =
         chain_asset_stats(chain, reissuance_token, afn).burned_amount;
 
-    let mempool = query.mempool();
     let mut mempool_stats = mempool_asset_stats(&mempool, &asset_id, afn);
     mempool_stats.burned_reissuance_tokens =
-        mempool_asset_stats(&mempool, &reissuance_token, afn).burned_amount;
+        mempool_asset_stats(mempool, &reissuance_token, afn).burned_amount;
 
     (chain_stats, mempool_stats)
 }