Refactor 'txSnapshot.ApplyInitialSnapshot'.

pkg/state/appender.go

@@ -628,6 +628,7 @@ func calculateInitialSnapshotStateHash(
 }
 
 func (a *txAppender) appendBlock(params *appendBlockParams) error {
+	const validatingUTX = false // we're applying a block, so it's false
 	// Reset block complexity counter.
 	defer func() {
 		a.sc.resetComplexity()
@@ -695,7 +696,7 @@ func (a *txAppender) appendBlock(params *appendBlockParams) error {
 	// TODO validate before reset
 	a.diffStor.reset()
 
-	err = initialSnapshot.ApplyInitialSnapshot(a.txHandler.sa)
+	err = initialSnapshot.ApplyInitialSnapshot(a.txHandler.sa, validatingUTX)
 	if err != nil {
 		return errors.Wrap(err, "failed to apply an initial snapshot")
 	}
@@ -749,7 +750,7 @@ func (a *txAppender) appendBlock(params *appendBlockParams) error {
 			consensusImprovementsActivated:   consensusImprovementsActivated,
 			blockRewardDistributionActivated: blockRewardDistributionActivated,
 			invokeExpressionActivated:        invokeExpressionActivated,
-			validatingUtx:                    false,
+			validatingUtx:                    validatingUTX,
 			currentMinerPK:                   params.block.GeneratorPublicKey,
 		}
 		txSnapshots, errAppendTx := a.appendTx(tx, appendTxArgs)
@@ -969,6 +970,7 @@ func (a *txAppender) handleFallible(
 
 // For UTX validation.
 func (a *txAppender) validateNextTx(tx proto.Transaction, currentTimestamp, parentTimestamp uint64, version proto.BlockVersion, acceptFailed bool) error {
+	const validatingUTX = true // we're validating a tx in UTX, so it's true
 	// TODO: Doesn't work correctly if miner doesn't work in NG mode.
 	// In this case it returns the last block instead of what is being mined.
 	block, err := a.currentBlock()
@@ -1036,7 +1038,7 @@ func (a *txAppender) validateNextTx(tx proto.Transaction, currentTimestamp, pare
 		consensusImprovementsActivated:   consensusImprovementsActivated,
 		blockRewardDistributionActivated: blockRewardDistributionActivated,
 		invokeExpressionActivated:        invokeExpressionActivated,
-		validatingUtx:                    true,
+		validatingUtx:                    validatingUTX,
 	}
 	_, err = a.appendTx(tx, appendTxArgs)
 	if err != nil {

pkg/state/snapshot_applier.go

@@ -12,11 +12,12 @@ import (
 )
 
 type txSnapshotContext struct {
-	initialized   bool
-	validatingUTX bool
 	applyingTx    proto.Transaction
+	validatingUTX bool
 }
 
+func (c txSnapshotContext) initialized() bool { return c.applyingTx != nil }
+
 type blockSnapshotsApplier struct {
 	info *blockSnapshotsApplierInfo
 	stor snapshotApplierStorages
@@ -32,9 +33,8 @@ type blockSnapshotsApplier struct {
 
 func (a *blockSnapshotsApplier) BeforeTxSnapshotApply(tx proto.Transaction, validatingUTX bool) error {
 	a.txSnapshotContext = txSnapshotContext{
-		initialized:   true,
-		validatingUTX: validatingUTX,
 		applyingTx:    tx,
+		validatingUTX: validatingUTX, // can be nil in case of initial snapshot applying
 	}
 	a.issuedAssets = []crypto.Digest{}
 	if len(a.scriptedAssets) != 0 {
@@ -335,7 +335,7 @@ func (a *blockSnapshotsApplier) ApplyCancelledLease(snapshot proto.CancelledLeas
 }
 
 func (a *blockSnapshotsApplier) ApplyTransactionsStatus(snapshot proto.TransactionStatusSnapshot) error {
-	if !a.txSnapshotContext.initialized { // sanity check
+	if !a.txSnapshotContext.initialized() { // sanity check
 		return errors.New("failed to apply transaction status snapshot: transaction is not set")
 	}
 	var (

pkg/state/tx_snapshot.go

@@ -46,19 +46,13 @@ func (ts txSnapshot) Apply(a extendedSnapshotApplier, tx proto.Transaction, vali
 	return nil
 }
 
-func (ts txSnapshot) ApplyInitialSnapshot(a extendedSnapshotApplier) error {
-	// internal snapshots must be applied at the end
-	for _, rs := range ts.regular {
-		err := rs.Apply(a)
-		if err != nil {
-			return errors.Wrap(err, "failed to apply regular transaction snapshot")
-		}
+func (ts txSnapshot) ApplyInitialSnapshot(a extendedSnapshotApplier, validatingUTX bool) error {
+	if validatingUTX { // sanity check
+		return errors.New("initial snapshot cannot be applied in validating UTX mode")
 	}
-	for _, is := range ts.internal {
-		err := is.ApplyInternal(a)
-		if err != nil {
-			return errors.Wrap(err, "failed to apply internal transaction snapshot")
-		}
+	var tx proto.Transaction // it's nil intentionally, because we're applying initial snapshot without TX
+	if err := ts.Apply(a, tx, validatingUTX); err != nil {
+		return errors.Wrap(err, "failed to apply initial block snapshot")
 	}
 	return nil
 }