Optimize the search process for BTC_TIME_LOCK ckb transactions

[ahonn]

For now, we use CKB RPC getTransactions to get all transactions that include BTC_TIME_LOCK cells, then get btc_txid from lock args.
Use btc_txid to determine whether the corresponding transaction is the corresponding CKB isomorphic transaction.

const btcTimeLockScript = getBtcTimeLockScript(isMainnet);
const txs = await fastify.ckbIndexer.getTransactions({
  script: {
    ...btcTimeLockScript,
    args: '0x',
  },
  scriptType: 'lock',
});

if (txs.objects.length > 0) {
  for (const { txHash } of txs.objects) {
    const tx = await fastify.ckbRPC.getTransaction(txHash);
    const isBtcTimeLockTx = tx.transaction.outputs.some((output) => {
      if (
        output.lock.codeHash !== btcTimeLockScript.codeHash ||
        output.lock.hashType !== btcTimeLockScript.hashType
      ) {
        return false;
      }
      const btcTxid = btcTxIdFromBtcTimeLockArgs(output.lock.args);
      return remove0x(btcTxid) === btc_txid;
    });
    if (isBtcTimeLockTx) {
      reply.header(CUSTOM_HEADERS.ResponseCacheable, 'true');
      return { txhash: txHash };
    }
  }
}

For CKB RPC getTransactions, we can optimize it through scriptSearchMode: 'partial' in the future to reduce the number of Cells that need to be checked and optimize the query speed.

But this depends on rich indexer, we need to wait for the node to support rich indexer.

References

• fix: fix btc time lock rgbpp transaction query rgbpp-explorer#85

[ahonn]

• Lumos issue: Add support for the new rich indexer ckb-js/lumos#656

[ahonn]

Rich indexer has been released: https://github.com/nervosnetwork/ckb/releases/tag/v0.115.0
We will be optimize cell collection after lumos supported.