1 files changed, 194 insertions, 0 deletions
diff --git a/ledger/evalindexer.go b/ledger/evalindexer.go
new file mode 100644
index 000000000..251e7c1f6
--- /dev/null
+++ b/ledger/evalindexer.go
@@ -0,0 +1,194 @@
+// Copyright (C) 2019-2021 Algorand, Inc.
+// This file is part of go-algorand
+//
+// go-algorand is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// go-algorand is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with go-algorand.  If not, see <https://www.gnu.org/licenses/>.
+
+package ledger
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/algorand/go-algorand/config"
+	"github.com/algorand/go-algorand/crypto"
+	"github.com/algorand/go-algorand/data/basics"
+	"github.com/algorand/go-algorand/data/bookkeeping"
+	"github.com/algorand/go-algorand/data/transactions"
+	"github.com/algorand/go-algorand/ledger/internal"
+	"github.com/algorand/go-algorand/ledger/ledgercore"
+)
+
+// A ledger interface that Indexer implements. This is a simplified version of the
+// LedgerForEvaluator interface. Certain functions that the evaluator doesn't use
+// in the trusting mode are excluded, and the present functions only request data
+// at the latest round.
+type indexerLedgerForEval interface {
+	LatestBlockHdr() (bookkeeping.BlockHeader, error)
+	// The value of the returned map is nil iff the account was not found.
+	LookupWithoutRewards(map[basics.Address]struct{}) (map[basics.Address]*basics.AccountData, error)
+	GetAssetCreator(map[basics.AssetIndex]struct{}) (map[basics.AssetIndex]FoundAddress, error)
+	GetAppCreator(map[basics.AppIndex]struct{}) (map[basics.AppIndex]FoundAddress, error)
+	LatestTotals() (ledgercore.AccountTotals, error)
+}
+
+// FoundAddress is a wrapper for an address and a boolean.
+type FoundAddress struct {
+	Address basics.Address
+	Exists  bool
+}
+
+// EvalForIndexerResources contains resources preloaded from the Indexer database.
+// Indexer is able to do the preloading more efficiently than the evaluator loading
+// resources one by one.
+type EvalForIndexerResources struct {
+	// The map value is nil iff the account does not exist. The account data is owned here.
+	Accounts map[basics.Address]*basics.AccountData
+	Creators map[Creatable]FoundAddress
+}
+
+// Creatable represent a single creatable object.
+type Creatable struct {
+	Index basics.CreatableIndex
+	Type  basics.CreatableType
+}
+
+// Converter between indexerLedgerForEval and ledgerForEvaluator interfaces.
+type indexerLedgerConnector struct {
+	il             indexerLedgerForEval
+	genesisHash    crypto.Digest
+	latestRound    basics.Round
+	roundResources EvalForIndexerResources
+}
+
+// BlockHdr is part of LedgerForEvaluator interface.
+func (l indexerLedgerConnector) BlockHdr(round basics.Round) (bookkeeping.BlockHeader, error) {
+	if round != l.latestRound {
+		return bookkeeping.BlockHeader{}, fmt.Errorf(
+			"BlockHdr() evaluator called this function for the wrong round %d, "+
+				"latest round is %d",
+			round, l.latestRound)
+	}
+	return l.il.LatestBlockHdr()
+}
+
+// CheckDup is part of LedgerForEvaluator interface.
+func (l indexerLedgerConnector) CheckDup(config.ConsensusParams, basics.Round, basics.Round, basics.Round, transactions.Txid, ledgercore.Txlease) error {
+	// This function is not used by evaluator.
+	return errors.New("CheckDup() not implemented")
+}
+
+// LookupWithoutRewards is part of LedgerForEvaluator interface.
+func (l indexerLedgerConnector) LookupWithoutRewards(round basics.Round, address basics.Address) (basics.AccountData, basics.Round, error) {
+	// check to see if the account data in the cache.
+	if pad, has := l.roundResources.Accounts[address]; has {
+		if pad == nil {
+			return basics.AccountData{}, round, nil
+		}
+		return *pad, round, nil
+	}
+
+	accountDataMap, err :=
+		l.il.LookupWithoutRewards(map[basics.Address]struct{}{address: {}})
+	if err != nil {
+		return basics.AccountData{}, basics.Round(0), err
+	}
+
+	accountData := accountDataMap[address]
+	if accountData == nil {
+		return basics.AccountData{}, round, nil
+	}
+	return *accountData, round, nil
+}
+
+// GetCreatorForRound is part of LedgerForEvaluator interface.
+func (l indexerLedgerConnector) GetCreatorForRound(_ basics.Round, cindex basics.CreatableIndex, ctype basics.CreatableType) (basics.Address, bool, error) {
+	var foundAddress FoundAddress
+	var has bool
+	// check to see if the account data in the cache.
+	if foundAddress, has = l.roundResources.Creators[Creatable{Index: cindex, Type: ctype}]; has {
+		return foundAddress.Address, foundAddress.Exists, nil
+	}
+
+	switch ctype {
+	case basics.AssetCreatable:
+		foundAddresses, err :=
+			l.il.GetAssetCreator(map[basics.AssetIndex]struct{}{basics.AssetIndex(cindex): {}})
+		if err != nil {
+			return basics.Address{}, false, err
+		}
+		foundAddress = foundAddresses[basics.AssetIndex(cindex)]
+	case basics.AppCreatable:
+		foundAddresses, err :=
+			l.il.GetAppCreator(map[basics.AppIndex]struct{}{basics.AppIndex(cindex): {}})
+		if err != nil {
+			return basics.Address{}, false, err
+		}
+		foundAddress = foundAddresses[basics.AppIndex(cindex)]
+	default:
+		return basics.Address{}, false, fmt.Errorf("unknown creatable type %v", ctype)
+	}
+
+	return foundAddress.Address, foundAddress.Exists, nil
+}
+
+// GenesisHash is part of LedgerForEvaluator interface.
+func (l indexerLedgerConnector) GenesisHash() crypto.Digest {
+	return l.genesisHash
+}
+
+// Totals is part of LedgerForEvaluator interface.
+func (l indexerLedgerConnector) LatestTotals() (rnd basics.Round, totals ledgercore.AccountTotals, err error) {
+	totals, err = l.il.LatestTotals()
+	rnd = l.latestRound
+	return
+}
+
+// CompactCertVoters is part of LedgerForEvaluator interface.
+func (l indexerLedgerConnector) CompactCertVoters(_ basics.Round) (*ledgercore.VotersForRound, error) {
+	// This function is not used by evaluator.
+	return nil, errors.New("CompactCertVoters() not implemented")
+}
+
+func makeIndexerLedgerConnector(il indexerLedgerForEval, genesisHash crypto.Digest, latestRound basics.Round, roundResources EvalForIndexerResources) indexerLedgerConnector {
+	return indexerLedgerConnector{
+		il:             il,
+		genesisHash:    genesisHash,
+		latestRound:    latestRound,
+		roundResources: roundResources,
+	}
+}
+
+// EvalForIndexer evaluates a block without validation using the given `proto`.
+// Return the state delta and transactions with modified apply data according to `proto`.
+// This function is used by Indexer which modifies `proto` to retrieve the asset
+// close amount for each transaction even when the real consensus parameters do not
+// support it.
+func EvalForIndexer(il indexerLedgerForEval, block *bookkeeping.Block, proto config.ConsensusParams, resources EvalForIndexerResources) (ledgercore.StateDelta, []transactions.SignedTxnInBlock, error) {
+	ilc := makeIndexerLedgerConnector(il, block.GenesisHash(), block.Round()-1, resources)
+
+	eval, err := internal.StartEvaluator(
+		ilc, block.BlockHeader,
+		internal.EvaluatorOptions{
+			PaysetHint:  len(block.Payset),
+			ProtoParams: &proto,
+			Generate:    false,
+			Validate:    false,
+		})
+	if err != nil {
+		return ledgercore.StateDelta{}, []transactions.SignedTxnInBlock{},
+			fmt.Errorf("EvalForIndexer() err: %w", err)
+	}
+
+	return eval.ProcessBlockForIndexer(block)
+}