From 89bc7f37dade1fbd6f840b0f92f504834a2ce484 Mon Sep 17 00:00:00 2001
From: Alex Rea <git@area.io>
Date: Mon, 20 Feb 2023 14:37:28 +0000
Subject: [PATCH] Make fetching logs from fork efficient

---
 .../src/data-managers/blocklog-manager.ts     | 45 +++++++++++++++----
 1 file changed, 37 insertions(+), 8 deletions(-)

diff --git a/src/chains/ethereum/ethereum/src/data-managers/blocklog-manager.ts b/src/chains/ethereum/ethereum/src/data-managers/blocklog-manager.ts
index dd32185f85..f13491e607 100644
--- a/src/chains/ethereum/ethereum/src/data-managers/blocklog-manager.ts
+++ b/src/chains/ethereum/ethereum/src/data-managers/blocklog-manager.ts
@@ -5,6 +5,7 @@ import Blockchain from "../blockchain";
 import { parseFilter, parseFilterDetails } from "../helpers/filter-parsing";
 import { Ethereum } from "../api-types";
 import { GanacheLevelUp } from "../database";
+type Topic = string | string[];
 
 export default class BlockLogManager extends Manager<BlockLogs> {
   #blockchain: Blockchain;
@@ -28,6 +29,19 @@ export default class BlockLogManager extends Manager<BlockLogs> {
     return log;
   }
 
+  async getRange(fromBlockNumber: string | Buffer, toBlockNumber: string | Buffer, topics: Topic[], address: String | String[]) {
+    const blockchain = this.#blockchain;
+    if (!blockchain.fallback){
+      throw new Error("Not a forked instance");
+    }
+    const res = await this.#blockchain.fallback.request<any[] | null>(
+      "eth_getLogs",
+      [{ address, topics, fromBlock: Quantity.from(fromBlockNumber), toBlock: Quantity.from(toBlockNumber) }]
+    );
+    return BlockLogs.fromJSON(res);
+
+  }
+
   async getLogs(filter: FilterArgs): Promise<Ethereum.Logs> {
     const blockchain = this.#blockchain;
     if ("blockHash" in filter) {
@@ -44,19 +58,34 @@ export default class BlockLogManager extends Manager<BlockLogs> {
         filter,
         blockchain
       );
-
-      const pendingLogsPromises: Promise<BlockLogs>[] = [
-        this.get(fromBlock.toBuffer())
-      ];
+      const pendingLogsPromises: Promise<BlockLogs>[] = [];
 
       const fromBlockNumber = fromBlock.toNumber();
       // if we have a range of blocks to search, do that here:
       if (fromBlockNumber !== toBlockNumber) {
-        // fetch all the blockLogs in-between `fromBlock` and `toBlock` (excluding
-        // from, because we already started fetching that one)
-        for (let i = fromBlockNumber + 1, l = toBlockNumber + 1; i < l; i++) {
-          pendingLogsPromises.push(this.get(Quantity.toBuffer(i)));
+        if (
+          !blockchain.fallback || // We're not a forked chain
+          blockchain.fallback.blockNumber < fromBlock // Or we are, but only querying post-fork
+        ) {
+          // fetch all the blockLogs in-between `fromBlock` and `toBlock`
+          for (let i = fromBlockNumber, l = toBlockNumber + 1; i < l; i++) {
+            pendingLogsPromises.push(this.get(Quantity.toBuffer(i)));
+          }
+        } else {
+          // Fetch all the logs from fromBlockNumber to forkBlock in one request
+          let addressesAsStrings: String[]|String;
+          if (Array.isArray(addresses)){
+            addressesAsStrings = addresses.map(x => `0x${x.toString('hex')}`)
+          }
+          pendingLogsPromises.push(this.getRange(Quantity.from(fromBlockNumber).toString(), Quantity.from(toBlockNumber).toString(), topics, addressesAsStrings ));
+          // fetch all the blockLogs in-between `forkBlock` + 1 and `toBlock` locally in the
+          // way that we normally do
+          for (let i = blockchain.fallback.blockNumber.toNumber() + 1, l = toBlockNumber + 1; i < l; i++) {
+            pendingLogsPromises.push(this.get(Quantity.toBuffer(i)));
+          }
         }
+      } else {
+        pendingLogsPromises.push(this.get(Quantity.toBuffer(fromBlockNumber)));
       }
 
       // now filter and compute all the blocks' blockLogs (in block order)