interop: wrap contract.LoadToken in context.LoadToken

Creating a closure in runtime is a relatively costly thing, but it can easily
be avoided.

pkg/compiler/interop_test.go

@@ -202,7 +202,7 @@ func TestAppCall(t *testing.T) {
 
 	fc := fakechain.NewFakeChain()
 	ic := interop.NewContext(trigger.Application, fc, dao.NewSimple(storage.NewMemoryStore(), false, false),
-		interop.DefaultBaseExecFee, native.DefaultStoragePrice, contractGetter, nil, nil, nil, zaptest.NewLogger(t))
+		interop.DefaultBaseExecFee, native.DefaultStoragePrice, contractGetter, nil, nil, nil, nil, zaptest.NewLogger(t))
 
 	t.Run("valid script", func(t *testing.T) {
 		src := getAppCallScript(fmt.Sprintf("%#v", ih.BytesBE()))

pkg/core/blockchain.go

@@ -1110,7 +1110,6 @@ func (bc *Blockchain) storeBlock(block *block.Block, txpool *mempool.Pool) error
 		v := systemInterop.SpawnVM()
 		v.LoadScriptWithFlags(tx.Script, callflag.All)
 		v.SetPriceGetter(systemInterop.GetPrice)
-		v.LoadToken = contract.LoadToken(systemInterop)
 		v.GasLimit = tx.SystemFee
 
 		err := systemInterop.Exec()
@@ -2169,7 +2168,6 @@ func (bc *Blockchain) GetTestVM(t trigger.Type, tx *transaction.Transaction, b *
 	systemInterop := bc.newInteropContext(t, bc.dao, b, tx)
 	vm := systemInterop.SpawnVM()
 	vm.SetPriceGetter(systemInterop.GetPrice)
-	vm.LoadToken = contract.LoadToken(systemInterop)
 	return systemInterop
 }
 
@@ -2204,7 +2202,6 @@ func (bc *Blockchain) GetTestHistoricVM(t trigger.Type, tx *transaction.Transact
 	systemInterop := bc.newInteropContext(t, dTrie, b, tx)
 	vm := systemInterop.SpawnVM()
 	vm.SetPriceGetter(systemInterop.GetPrice)
-	vm.LoadToken = contract.LoadToken(systemInterop)
 	return systemInterop, nil
 }
 
@@ -2280,7 +2277,6 @@ func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transa
 
 	vm := interopCtx.SpawnVM()
 	vm.SetPriceGetter(interopCtx.GetPrice)
-	vm.LoadToken = contract.LoadToken(interopCtx)
 	vm.GasLimit = gas
 	if err := bc.InitVerificationContext(interopCtx, hash, witness); err != nil {
 		return 0, err
@@ -2376,7 +2372,7 @@ func (bc *Blockchain) newInteropContext(trigger trigger.Type, d *dao.Simple, blo
 		// changes that were not yet persisted to Blockchain's dao.
 		baseStorageFee = bc.contracts.Policy.GetStoragePriceInternal(d)
 	}
-	ic := interop.NewContext(trigger, bc, d, baseExecFee, baseStorageFee, bc.contracts.Management.GetContract, bc.contracts.Contracts, block, tx, bc.log)
+	ic := interop.NewContext(trigger, bc, d, baseExecFee, baseStorageFee, bc.contracts.Management.GetContract, bc.contracts.Contracts, contract.LoadToken, block, tx, bc.log)
 	ic.Functions = systemInterops
 	switch {
 	case tx != nil:

pkg/core/interop/context.go

@@ -64,6 +64,7 @@ type Context struct {
 	getContract      func(*dao.Simple, util.Uint160) (*state.Contract, error)
 	baseExecFee      int64
 	baseStorageFee   int64
+	loadToken        func(ic *Context, id int32) error
 	GetRandomCounter uint32
 	signers          []transaction.Signer
 }
@@ -71,6 +72,7 @@ type Context struct {
 // NewContext returns new interop context.
 func NewContext(trigger trigger.Type, bc Ledger, d *dao.Simple, baseExecFee, baseStorageFee int64,
 	getContract func(*dao.Simple, util.Uint160) (*state.Contract, error), natives []Contract,
+	loadTokenFunc func(ic *Context, id int32) error,
 	block *block.Block, tx *transaction.Transaction, log *zap.Logger) *Context {
 	dao := d.GetPrivate()
 	cfg := bc.GetConfig()
@@ -88,6 +90,7 @@ func NewContext(trigger trigger.Type, bc Ledger, d *dao.Simple, baseExecFee, bas
 		getContract:    getContract,
 		baseExecFee:    baseExecFee,
 		baseStorageFee: baseStorageFee,
+		loadToken:      loadTokenFunc,
 	}
 }
 
@@ -298,6 +301,12 @@ func (ic *Context) BaseStorageFee() int64 {
 	return ic.baseStorageFee
 }
 
+// LoadToken wraps externally provided load-token loading function providing it with context,
+// this function can then be easily used by VM.
+func (ic *Context) LoadToken(id int32) error {
+	return ic.loadToken(ic, id)
+}
+
 // SyscallHandler handles syscall with id.
 func (ic *Context) SyscallHandler(_ *vm.VM, id uint32) error {
 	f := ic.GetFunction(id)
@@ -317,6 +326,7 @@ func (ic *Context) SyscallHandler(_ *vm.VM, id uint32) error {
 // SpawnVM spawns a new VM with the specified gas limit and set context.VM field.
 func (ic *Context) SpawnVM() *vm.VM {
 	v := vm.NewWithTrigger(ic.Trigger)
+	v.LoadToken = ic.LoadToken
 	v.GasLimit = -1
 	v.SyscallHandler = ic.SyscallHandler
 	ic.VM = v

pkg/core/interop/contract/call.go

@@ -22,8 +22,7 @@ type policyChecker interface {
 }
 
 // LoadToken calls method specified by the token id.
-func LoadToken(ic *interop.Context) func(id int32) error {
+func LoadToken(ic *interop.Context, id int32) error {
-	return func(id int32) error {
 	ctx := ic.VM.Context()
 	if !ctx.GetCallFlags().Has(callflag.ReadStates | callflag.AllowCall) {
 		return errors.New("invalid call flags")
@@ -41,7 +40,6 @@ func LoadToken(ic *interop.Context) func(id int32) error {
 		return fmt.Errorf("token contract %s not found: %w", tok.Hash.StringLE(), err)
 	}
 	return callInternal(ic, cs, tok.Method, tok.CallFlag, tok.HasReturn, args, false)
-	}
 }
 
 // Call calls a contract with flags.

pkg/core/interop/crypto/ecdsa_test.go

@@ -73,7 +73,7 @@ func initCheckMultisigVMNoArgs(container *transaction.Transaction) *vm.VM {
 		trigger.Verification,
 		fakechain.NewFakeChain(),
 		dao.NewSimple(storage.NewMemoryStore(), false, false),
-		interop.DefaultBaseExecFee, native.DefaultStoragePrice, nil, nil, nil,
+		interop.DefaultBaseExecFee, native.DefaultStoragePrice, nil, nil, nil, nil,
 		container,
 		nil)
 	ic.Container = container