Merge pull request #2621 from nspcc-dev/sc-params

Smartcontract Parameters and Invoker interface

pkg/rpcclient/client.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/neorpc"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/invoker"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"go.uber.org/atomic"
 )
@@ -35,6 +36,11 @@ type Client struct {
 	opts     Options
 	requestF func(*neorpc.Request) (*neorpc.Response, error)
 
+	// reader is an Invoker that has no signers and uses current state,
+	// it's used to implement various getters. It'll be removed eventually,
+	// but for now it keeps Client's API compatibility.
+	reader *invoker.Invoker
+
 	cacheLock sync.RWMutex
 	// cache stores RPC node related information the client is bound to.
 	// cache is mostly filled in during Init(), but can also be updated
@@ -128,6 +134,7 @@ func initClient(ctx context.Context, cl *Client, endpoint string, opts Options)
 	cl.getNextRequestID = (cl).getRequestID
 	cl.opts = opts
 	cl.requestF = cl.makeHTTPRequest
+	cl.reader = invoker.New(cl, nil)
 	return nil
 }
 

pkg/rpcclient/helper.go

@@ -111,12 +111,22 @@ func topMapFromStack(st []stackitem.Item) (*stackitem.Map, error) {
 // retrieve iterator values via single `invokescript` JSON-RPC call. It returns
 // maxIteratorResultItems items at max which is set to
 // config.DefaultMaxIteratorResultItems by default.
+//
+// Deprecated: please use more convenient and powerful invoker.Invoker interface with
+// CallAndExpandIterator method. This method will be removed in future versions.
 func (c *Client) InvokeAndPackIteratorResults(contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer, maxIteratorResultItems ...int) (*result.Invoke, error) {
 	max := config.DefaultMaxIteratorResultItems
 	if len(maxIteratorResultItems) != 0 {
 		max = maxIteratorResultItems[0]
 	}
-	bytes, err := smartcontract.CreateCallAndUnwrapIteratorScript(contract, operation, params, max)
+	values, err := smartcontract.ExpandParameterToEmitable(smartcontract.Parameter{
+		Type:  smartcontract.ArrayType,
+		Value: params,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("expanding params to emitable: %w", err)
+	}
+	bytes, err := smartcontract.CreateCallAndUnwrapIteratorScript(contract, operation, max, values.([]interface{})...)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create iterator unwrapper script: %w", err)
 	}

pkg/rpcclient/invoker/invoker.go

@@ -0,0 +1,159 @@
+package invoker
+
+import (
+	"fmt"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+)
+
+// RPCInvoke is a set of RPC methods needed to execute things at the current
+// blockchain height.
+type RPCInvoke interface {
+	InvokeContractVerify(contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error)
+	InvokeFunction(contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error)
+	InvokeScript(script []byte, signers []transaction.Signer) (*result.Invoke, error)
+}
+
+// RPCInvokeHistoric is a set of RPC methods needed to execute things at some
+// fixed point in blockchain's life.
+type RPCInvokeHistoric interface {
+	InvokeContractVerifyAtBlock(blockHash util.Uint256, contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error)
+	InvokeContractVerifyAtHeight(height uint32, contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error)
+	InvokeContractVerifyWithState(stateroot util.Uint256, contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error)
+	InvokeFunctionAtBlock(blockHash util.Uint256, contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error)
+	InvokeFunctionAtHeight(height uint32, contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error)
+	InvokeFunctionWithState(stateroot util.Uint256, contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error)
+	InvokeScriptAtBlock(blockHash util.Uint256, script []byte, signers []transaction.Signer) (*result.Invoke, error)
+	InvokeScriptAtHeight(height uint32, script []byte, signers []transaction.Signer) (*result.Invoke, error)
+	InvokeScriptWithState(stateroot util.Uint256, script []byte, signers []transaction.Signer) (*result.Invoke, error)
+}
+
+// Invoker allows to test-execute things using RPC client. Its API simplifies
+// reusing the same signers list for a series of invocations and at the
+// same time uses regular Go types for call parameters. It doesn't do anything with
+// the result of invocation, that's left for upper (contract) layer to deal with.
+// Invoker does not produce any transactions and does not change the state of the
+// chain.
+type Invoker struct {
+	client  RPCInvoke
+	signers []transaction.Signer
+}
+
+type historicConverter struct {
+	client RPCInvokeHistoric
+	block  *util.Uint256
+	height *uint32
+	root   *util.Uint256
+}
+
+// New creates an Invoker to test-execute things at the current blockchain height.
+func New(client RPCInvoke, signers []transaction.Signer) *Invoker {
+	return &Invoker{client, signers}
+}
+
+// NewHistoricAtBlock creates an Invoker to test-execute things at some given block.
+func NewHistoricAtBlock(block util.Uint256, client RPCInvokeHistoric, signers []transaction.Signer) *Invoker {
+	return New(&historicConverter{
+		client: client,
+		block:  &block,
+	}, signers)
+}
+
+// NewHistoricAtHeight creates an Invoker to test-execute things at some given height.
+func NewHistoricAtHeight(height uint32, client RPCInvokeHistoric, signers []transaction.Signer) *Invoker {
+	return New(&historicConverter{
+		client: client,
+		height: &height,
+	}, signers)
+}
+
+// NewHistoricWithState creates an Invoker to test-execute things with some given state.
+func NewHistoricWithState(root util.Uint256, client RPCInvokeHistoric, signers []transaction.Signer) *Invoker {
+	return New(&historicConverter{
+		client: client,
+		root:   &root,
+	}, signers)
+}
+
+func (h *historicConverter) InvokeScript(script []byte, signers []transaction.Signer) (*result.Invoke, error) {
+	if h.block != nil {
+		return h.client.InvokeScriptAtBlock(*h.block, script, signers)
+	}
+	if h.height != nil {
+		return h.client.InvokeScriptAtHeight(*h.height, script, signers)
+	}
+	if h.root != nil {
+		return h.client.InvokeScriptWithState(*h.root, script, signers)
+	}
+	panic("uninitialized historicConverter")
+}
+
+func (h *historicConverter) InvokeFunction(contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error) {
+	if h.block != nil {
+		return h.client.InvokeFunctionAtBlock(*h.block, contract, operation, params, signers)
+	}
+	if h.height != nil {
+		return h.client.InvokeFunctionAtHeight(*h.height, contract, operation, params, signers)
+	}
+	if h.root != nil {
+		return h.client.InvokeFunctionWithState(*h.root, contract, operation, params, signers)
+	}
+	panic("uninitialized historicConverter")
+}
+
+func (h *historicConverter) InvokeContractVerify(contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error) {
+	if h.block != nil {
+		return h.client.InvokeContractVerifyAtBlock(*h.block, contract, params, signers, witnesses...)
+	}
+	if h.height != nil {
+		return h.client.InvokeContractVerifyAtHeight(*h.height, contract, params, signers, witnesses...)
+	}
+	if h.root != nil {
+		return h.client.InvokeContractVerifyWithState(*h.root, contract, params, signers, witnesses...)
+	}
+	panic("uninitialized historicConverter")
+}
+
+// Call invokes a method of the contract with the given parameters (and
+// Invoker-specific list of signers) and returns the result as is.
+func (v *Invoker) Call(contract util.Uint160, operation string, params ...interface{}) (*result.Invoke, error) {
+	ps, err := smartcontract.NewParametersFromValues(params...)
+	if err != nil {
+		return nil, err
+	}
+	return v.client.InvokeFunction(contract, operation, ps, v.signers)
+}
+
+// CallAndExpandIterator creates a script containing a call of the specified method
+// of a contract with given parameters (similar to how Call operates). But then this
+// script contains additional code that expects that the result of the first call is
+// an iterator. This iterator is traversed extracting values from it and adding them
+// into an array until maxItems is reached or iterator has no more elements. The
+// result of the whole script is an array containing up to maxResultItems elements
+// from the iterator returned from the contract's method call. This script is executed
+// using regular JSON-API (according to the way Iterator is set up).
+func (v *Invoker) CallAndExpandIterator(contract util.Uint160, method string, maxItems int, params ...interface{}) (*result.Invoke, error) {
+	bytes, err := smartcontract.CreateCallAndUnwrapIteratorScript(contract, method, maxItems, params...)
+	if err != nil {
+		return nil, fmt.Errorf("iterator unwrapper script: %w", err)
+	}
+	return v.Run(bytes)
+}
+
+// Verify invokes contract's verify method in the verification context with
+// Invoker-specific signers and given witnesses and parameters.
+func (v *Invoker) Verify(contract util.Uint160, witnesses []transaction.Witness, params ...interface{}) (*result.Invoke, error) {
+	ps, err := smartcontract.NewParametersFromValues(params...)
+	if err != nil {
+		return nil, err
+	}
+	return v.client.InvokeContractVerify(contract, ps, v.signers, witnesses...)
+}
+
+// Run executes given bytecode with Invoker-specific list of signers.
+func (v *Invoker) Run(script []byte) (*result.Invoke, error) {
+	return v.client.InvokeScript(script, v.signers)
+}

pkg/rpcclient/invoker/invoker_test.go

@@ -0,0 +1,115 @@
+package invoker
+
+import (
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/stretchr/testify/require"
+)
+
+type rpcInv struct {
+	resInv *result.Invoke
+	err    error
+}
+
+func (r *rpcInv) InvokeContractVerify(contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeFunction(contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeScript(script []byte, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeContractVerifyAtBlock(blockHash util.Uint256, contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeContractVerifyAtHeight(height uint32, contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeContractVerifyWithState(stateroot util.Uint256, contract util.Uint160, params []smartcontract.Parameter, signers []transaction.Signer, witnesses ...transaction.Witness) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeFunctionAtBlock(blockHash util.Uint256, contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeFunctionAtHeight(height uint32, contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeFunctionWithState(stateroot util.Uint256, contract util.Uint160, operation string, params []smartcontract.Parameter, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeScriptAtBlock(blockHash util.Uint256, script []byte, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeScriptAtHeight(height uint32, script []byte, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+func (r *rpcInv) InvokeScriptWithState(stateroot util.Uint256, script []byte, signers []transaction.Signer) (*result.Invoke, error) {
+	return r.resInv, r.err
+}
+
+func TestInvoker(t *testing.T) {
+	resExp := &result.Invoke{State: "HALT"}
+	ri := &rpcInv{resExp, nil}
+
+	testInv := func(t *testing.T, inv *Invoker) {
+		res, err := inv.Call(util.Uint160{}, "method")
+		require.NoError(t, err)
+		require.Equal(t, resExp, res)
+
+		res, err = inv.Verify(util.Uint160{}, nil)
+		require.NoError(t, err)
+		require.Equal(t, resExp, res)
+
+		res, err = inv.Run([]byte{1})
+		require.NoError(t, err)
+		require.Equal(t, resExp, res)
+
+		res, err = inv.Call(util.Uint160{}, "method")
+		require.NoError(t, err)
+		require.Equal(t, resExp, res)
+
+		res, err = inv.Verify(util.Uint160{}, nil, "param")
+		require.NoError(t, err)
+		require.Equal(t, resExp, res)
+
+		res, err = inv.Call(util.Uint160{}, "method", 42)
+		require.NoError(t, err)
+		require.Equal(t, resExp, res)
+
+		_, err = inv.Verify(util.Uint160{}, nil, make(map[int]int))
+		require.Error(t, err)
+
+		_, err = inv.Call(util.Uint160{}, "method", make(map[int]int))
+		require.Error(t, err)
+
+		res, err = inv.CallAndExpandIterator(util.Uint160{}, "method", 10, 42)
+		require.NoError(t, err)
+		require.Equal(t, resExp, res)
+
+		_, err = inv.CallAndExpandIterator(util.Uint160{}, "method", 10, make(map[int]int))
+		require.Error(t, err)
+	}
+	t.Run("standard", func(t *testing.T) {
+		testInv(t, New(ri, nil))
+	})
+	t.Run("historic, block", func(t *testing.T) {
+		testInv(t, NewHistoricAtBlock(util.Uint256{}, ri, nil))
+	})
+	t.Run("historic, height", func(t *testing.T) {
+		testInv(t, NewHistoricAtHeight(100500, ri, nil))
+	})
+	t.Run("historic, state", func(t *testing.T) {
+		testInv(t, NewHistoricWithState(util.Uint256{}, ri, nil))
+	})
+	t.Run("broken historic", func(t *testing.T) {
+		inv := New(&historicConverter{client: ri}, nil) // It's not possible to do this from outside.
+		require.Panics(t, func() { _, _ = inv.Call(util.Uint160{}, "method") })
+		require.Panics(t, func() { _, _ = inv.Verify(util.Uint160{}, nil, "param") })
+		require.Panics(t, func() { _, _ = inv.Run([]byte{1}) })
+	})
+}

pkg/rpcclient/native.go

@@ -5,15 +5,14 @@ package rpcclient
 import (
 	"errors"
 	"fmt"
-	"math/big"
 
 	"github.com/google/uuid"
+	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
 	"github.com/nspcc-dev/neo-go/pkg/core/native/noderoles"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/nns"
-	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
@@ -55,16 +54,7 @@ func (c *Client) GetDesignatedByRole(role noderoles.Role, index uint32) (keys.Pu
 	if err != nil {
 		return nil, fmt.Errorf("failed to get native RoleManagement hash: %w", err)
 	}
-	result, err := c.InvokeFunction(rmHash, "getDesignatedByRole", []smartcontract.Parameter{
+	result, err := c.reader.Call(rmHash, "getDesignatedByRole", int64(role), index)
-		{
-			Type:  smartcontract.IntegerType,
-			Value: big.NewInt(int64(role)),
-		},
-		{
-			Type:  smartcontract.IntegerType,
-			Value: big.NewInt(int64(index)),
-		},
-	}, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -80,16 +70,7 @@ func (c *Client) NNSResolve(nnsHash util.Uint160, name string, typ nns.RecordTyp
 	if typ == nns.CNAME {
 		return "", errors.New("can't resolve CNAME record type")
 	}
-	result, err := c.InvokeFunction(nnsHash, "resolve", []smartcontract.Parameter{
+	result, err := c.reader.Call(nnsHash, "resolve", name, int64(typ))
-		{
-			Type:  smartcontract.StringType,
-			Value: name,
-		},
-		{
-			Type:  smartcontract.IntegerType,
-			Value: big.NewInt(int64(typ)),
-		},
-	}, nil)
 	if err != nil {
 		return "", err
 	}
@@ -102,12 +83,7 @@ func (c *Client) NNSResolve(nnsHash util.Uint160, name string, typ nns.RecordTyp
 
 // NNSIsAvailable invokes `isAvailable` method on a NeoNameService contract with the specified hash.
 func (c *Client) NNSIsAvailable(nnsHash util.Uint160, name string) (bool, error) {
-	result, err := c.InvokeFunction(nnsHash, "isAvailable", []smartcontract.Parameter{
+	result, err := c.reader.Call(nnsHash, "isAvailable", name)
-		{
-			Type:  smartcontract.StringType,
-			Value: name,
-		},
-	}, nil)
 	if err != nil {
 		return false, err
 	}
@@ -124,12 +100,7 @@ func (c *Client) NNSIsAvailable(nnsHash util.Uint160, name string) (bool, error)
 // TerminateSession to terminate opened iterator session. See TraverseIterator and
 // TerminateSession documentation for more details.
 func (c *Client) NNSGetAllRecords(nnsHash util.Uint160, name string) (uuid.UUID, result.Iterator, error) {
-	res, err := c.InvokeFunction(nnsHash, "getAllRecords", []smartcontract.Parameter{
+	res, err := c.reader.Call(nnsHash, "getAllRecords", name)
-		{
-			Type:  smartcontract.StringType,
-			Value: name,
-		},
-	}, nil)
 	if err != nil {
 		return uuid.UUID{}, result.Iterator{}, err
 	}
@@ -147,12 +118,7 @@ func (c *Client) NNSGetAllRecords(nnsHash util.Uint160, name string) (uuid.UUID,
 // that no iterator session is used to retrieve values from iterator. Instead, unpacking
 // VM script is created and invoked via `invokescript` JSON-RPC call.
 func (c *Client) NNSUnpackedGetAllRecords(nnsHash util.Uint160, name string) ([]nns.RecordState, error) {
-	result, err := c.InvokeAndPackIteratorResults(nnsHash, "getAllRecords", []smartcontract.Parameter{
+	result, err := c.reader.CallAndExpandIterator(nnsHash, "getAllRecords", config.DefaultMaxIteratorResultItems, name)
-		{
-			Type:  smartcontract.StringType,
-			Value: name,
-		},
-	}, nil)
 	if err != nil {
 		return nil, err
 	}

pkg/rpcclient/nep.go

@@ -3,14 +3,13 @@ package rpcclient
 import (
 	"fmt"
 
-	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/wallet"
 )
 
 // nepDecimals invokes `decimals` NEP* method on the specified contract.
 func (c *Client) nepDecimals(tokenHash util.Uint160) (int64, error) {
-	result, err := c.InvokeFunction(tokenHash, "decimals", []smartcontract.Parameter{}, nil)
+	result, err := c.reader.Call(tokenHash, "decimals")
 	if err != nil {
 		return 0, err
 	}
@@ -24,7 +23,7 @@ func (c *Client) nepDecimals(tokenHash util.Uint160) (int64, error) {
 
 // nepSymbol invokes `symbol` NEP* method on the specified contract.
 func (c *Client) nepSymbol(tokenHash util.Uint160) (string, error) {
-	result, err := c.InvokeFunction(tokenHash, "symbol", []smartcontract.Parameter{}, nil)
+	result, err := c.reader.Call(tokenHash, "symbol")
 	if err != nil {
 		return "", err
 	}
@@ -38,7 +37,7 @@ func (c *Client) nepSymbol(tokenHash util.Uint160) (string, error) {
 
 // nepTotalSupply invokes `totalSupply` NEP* method on the specified contract.
 func (c *Client) nepTotalSupply(tokenHash util.Uint160) (int64, error) {
-	result, err := c.InvokeFunction(tokenHash, "totalSupply", []smartcontract.Parameter{}, nil)
+	result, err := c.reader.Call(tokenHash, "totalSupply")
 	if err != nil {
 		return 0, err
 	}
@@ -52,17 +51,11 @@ func (c *Client) nepTotalSupply(tokenHash util.Uint160) (int64, error) {
 
 // nepBalanceOf invokes `balanceOf` NEP* method on the specified contract.
 func (c *Client) nepBalanceOf(tokenHash, acc util.Uint160, tokenID []byte) (int64, error) {
-	params := []smartcontract.Parameter{{
+	params := []interface{}{acc}
-		Type:  smartcontract.Hash160Type,
-		Value: acc,
-	}}
 	if tokenID != nil {
-		params = append(params, smartcontract.Parameter{
+		params = append(params, tokenID)
-			Type:  smartcontract.ByteArrayType,
-			Value: tokenID,
-		})
 	}
-	result, err := c.InvokeFunction(tokenHash, "balanceOf", params, nil)
+	result, err := c.reader.Call(tokenHash, "balanceOf", params...)
 	if err != nil {
 		return 0, err
 	}

pkg/rpcclient/nep11.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/google/uuid"
+	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
@@ -84,12 +85,7 @@ func (c *Client) CreateNEP11TransferTx(acc *wallet.Account, tokenHash util.Uint1
 // traverse iterator values or TerminateSession to terminate opened iterator
 // session. See TraverseIterator and TerminateSession documentation for more details.
 func (c *Client) NEP11TokensOf(tokenHash util.Uint160, owner util.Uint160) (uuid.UUID, result.Iterator, error) {
-	res, err := c.InvokeFunction(tokenHash, "tokensOf", []smartcontract.Parameter{
+	res, err := c.reader.Call(tokenHash, "tokensOf", owner)
-		{
-			Type:  smartcontract.Hash160Type,
-			Value: owner,
-		},
-	}, nil)
 	if err != nil {
 		return uuid.UUID{}, result.Iterator{}, err
 	}
@@ -106,12 +102,7 @@ func (c *Client) NEP11TokensOf(tokenHash util.Uint160, owner util.Uint160) (uuid
 // is used to retrieve values from iterator. Instead, unpacking VM script is created and invoked via
 // `invokescript` JSON-RPC call.
 func (c *Client) NEP11UnpackedTokensOf(tokenHash util.Uint160, owner util.Uint160) ([][]byte, error) {
-	result, err := c.InvokeAndPackIteratorResults(tokenHash, "tokensOf", []smartcontract.Parameter{
+	result, err := c.reader.CallAndExpandIterator(tokenHash, "tokensOf", config.DefaultMaxIteratorResultItems, owner)
-		{
-			Type:  smartcontract.Hash160Type,
-			Value: owner,
-		},
-	}, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -136,12 +127,7 @@ func (c *Client) NEP11UnpackedTokensOf(tokenHash util.Uint160, owner util.Uint16
 // NEP11NDOwnerOf invokes `ownerOf` non-divisible NEP-11 method with the
 // specified token ID on the specified contract.
 func (c *Client) NEP11NDOwnerOf(tokenHash util.Uint160, tokenID []byte) (util.Uint160, error) {
-	result, err := c.InvokeFunction(tokenHash, "ownerOf", []smartcontract.Parameter{
+	result, err := c.reader.Call(tokenHash, "ownerOf", tokenID)
-		{
-			Type:  smartcontract.ByteArrayType,
-			Value: tokenID,
-		},
-	}, nil)
 	if err != nil {
 		return util.Uint160{}, err
 	}
@@ -186,12 +172,7 @@ func (c *Client) NEP11DBalanceOf(tokenHash, owner util.Uint160, tokenID []byte)
 // method to traverse iterator values or TerminateSession to terminate opened iterator session. See
 // TraverseIterator and TerminateSession documentation for more details.
 func (c *Client) NEP11DOwnerOf(tokenHash util.Uint160, tokenID []byte) (uuid.UUID, result.Iterator, error) {
-	res, err := c.InvokeFunction(tokenHash, "ownerOf", []smartcontract.Parameter{
+	res, err := c.reader.Call(tokenHash, "ownerOf", tokenID)
-		{
-			Type:  smartcontract.ByteArrayType,
-			Value: tokenID,
-		},
-	}, nil)
 	sessID := res.Session
 	if err != nil {
 		return sessID, result.Iterator{}, err
@@ -209,12 +190,7 @@ func (c *Client) NEP11DOwnerOf(tokenHash util.Uint160, tokenID []byte) (uuid.UUI
 // iterator session is used to retrieve values from iterator. Instead, unpacking VM
 // script is created and invoked via `invokescript` JSON-RPC call.
 func (c *Client) NEP11DUnpackedOwnerOf(tokenHash util.Uint160, tokenID []byte) ([]util.Uint160, error) {
-	result, err := c.InvokeAndPackIteratorResults(tokenHash, "ownerOf", []smartcontract.Parameter{
+	result, err := c.reader.CallAndExpandIterator(tokenHash, "ownerOf", config.DefaultMaxIteratorResultItems, tokenID)
-		{
-			Type:  smartcontract.ByteArrayType,
-			Value: tokenID,
-		},
-	}, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -241,10 +217,7 @@ func (c *Client) NEP11DUnpackedOwnerOf(tokenHash util.Uint160, tokenID []byte) (
 // NEP11Properties invokes `properties` optional NEP-11 method on the
 // specified contract.
 func (c *Client) NEP11Properties(tokenHash util.Uint160, tokenID []byte) (*stackitem.Map, error) {
-	result, err := c.InvokeFunction(tokenHash, "properties", []smartcontract.Parameter{{
+	result, err := c.reader.Call(tokenHash, "properties", tokenID)
-		Type:  smartcontract.ByteArrayType,
-		Value: tokenID,
-	}}, nil)
 	if err != nil {
 		return nil, err
 	}
@@ -262,7 +235,7 @@ func (c *Client) NEP11Properties(tokenHash util.Uint160, tokenID []byte) (*stack
 // TerminateSession to terminate opened iterator session. See TraverseIterator and
 // TerminateSession documentation for more details.
 func (c *Client) NEP11Tokens(tokenHash util.Uint160) (uuid.UUID, result.Iterator, error) {
-	res, err := c.InvokeFunction(tokenHash, "tokens", []smartcontract.Parameter{}, nil)
+	res, err := c.reader.Call(tokenHash, "tokens")
 	if err != nil {
 		return uuid.UUID{}, result.Iterator{}, err
 	}
@@ -279,7 +252,7 @@ func (c *Client) NEP11Tokens(tokenHash util.Uint160) (uuid.UUID, result.Iterator
 // iterator session is used to retrieve values from iterator. Instead, unpacking
 // VM script is created and invoked via `invokescript` JSON-RPC call.
 func (c *Client) NEP11UnpackedTokens(tokenHash util.Uint160) ([][]byte, error) {
-	result, err := c.InvokeAndPackIteratorResults(tokenHash, "tokens", []smartcontract.Parameter{}, nil)
+	result, err := c.reader.CallAndExpandIterator(tokenHash, "tokens", config.DefaultMaxIteratorResultItems)
 	if err != nil {
 		return nil, err
 	}

pkg/rpcclient/policy.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
-	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
@@ -42,7 +41,7 @@ func (c *Client) invokeNativePolicyMethod(operation string) (int64, error) {
 }
 
 func (c *Client) invokeNativeGetMethod(hash util.Uint160, operation string) (int64, error) {
-	result, err := c.InvokeFunction(hash, operation, []smartcontract.Parameter{}, nil)
+	result, err := c.reader.Call(hash, operation)
 	if err != nil {
 		return 0, err
 	}
@@ -59,10 +58,7 @@ func (c *Client) IsBlocked(hash util.Uint160) (bool, error) {
 	if err != nil {
 		return false, fmt.Errorf("failed to get native Policy hash: %w", err)
 	}
-	result, err := c.InvokeFunction(policyHash, "isBlocked", []smartcontract.Parameter{{
+	result, err := c.reader.Call(policyHash, "isBlocked", hash)
-		Type:  smartcontract.Hash160Type,
-		Value: hash,
-	}}, nil)
 	if err != nil {
 		return false, err
 	}

pkg/rpcclient/rpc.go

@@ -1047,7 +1047,7 @@ func (c *Client) AddNetworkFee(tx *transaction.Transaction, extraFee int64, accs
 	var ef int64
 	for i, cosigner := range tx.Signers {
 		if accs[i].Contract.Deployed {
-			res, err := c.InvokeContractVerify(cosigner.Account, smartcontract.Params{}, tx.Signers)
+			res, err := c.InvokeContractVerify(cosigner.Account, []smartcontract.Parameter{}, tx.Signers)
 			if err != nil {
 				return fmt.Errorf("failed to invoke verify: %w", err)
 			}

pkg/services/rpcsrv/client_test.go

@@ -773,7 +773,7 @@ func TestInvokeVerify(t *testing.T) {
 	require.NoError(t, err)
 
 	t.Run("positive, with signer", func(t *testing.T) {
-		res, err := c.InvokeContractVerify(contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
+		res, err := c.InvokeContractVerify(contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
 		require.NoError(t, err)
 		require.Equal(t, "HALT", res.State)
 		require.Equal(t, 1, len(res.Stack))
@@ -782,7 +782,7 @@ func TestInvokeVerify(t *testing.T) {
 
 	t.Run("positive, historic, by height, with signer", func(t *testing.T) {
 		h := chain.BlockHeight() - 1
-		res, err := c.InvokeContractVerifyAtHeight(h, contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
+		res, err := c.InvokeContractVerifyAtHeight(h, contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
 		require.NoError(t, err)
 		require.Equal(t, "HALT", res.State)
 		require.Equal(t, 1, len(res.Stack))
@@ -790,7 +790,7 @@ func TestInvokeVerify(t *testing.T) {
 	})
 
 	t.Run("positive, historic, by block, with signer", func(t *testing.T) {
-		res, err := c.InvokeContractVerifyAtBlock(chain.GetHeaderHash(int(chain.BlockHeight())-1), contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
+		res, err := c.InvokeContractVerifyAtBlock(chain.GetHeaderHash(int(chain.BlockHeight())-1), contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
 		require.NoError(t, err)
 		require.Equal(t, "HALT", res.State)
 		require.Equal(t, 1, len(res.Stack))
@@ -801,7 +801,7 @@ func TestInvokeVerify(t *testing.T) {
 		h := chain.BlockHeight() - 1
 		sr, err := chain.GetStateModule().GetStateRoot(h)
 		require.NoError(t, err)
-		res, err := c.InvokeContractVerifyWithState(sr.Root, contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
+		res, err := c.InvokeContractVerifyWithState(sr.Root, contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
 		require.NoError(t, err)
 		require.Equal(t, "HALT", res.State)
 		require.Equal(t, 1, len(res.Stack))
@@ -810,13 +810,13 @@ func TestInvokeVerify(t *testing.T) {
 
 	t.Run("bad, historic, by hash: contract not found", func(t *testing.T) {
 		var h uint32 = 1
-		_, err = c.InvokeContractVerifyAtHeight(h, contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
+		_, err = c.InvokeContractVerifyAtHeight(h, contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
 		require.Error(t, err)
 		require.True(t, strings.Contains(err.Error(), core.ErrUnknownVerificationContract.Error())) // contract wasn't deployed at block #1 yet
 	})
 
 	t.Run("bad, historic, by block: contract not found", func(t *testing.T) {
-		_, err = c.InvokeContractVerifyAtBlock(chain.GetHeaderHash(1), contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
+		_, err = c.InvokeContractVerifyAtBlock(chain.GetHeaderHash(1), contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
 		require.Error(t, err)
 		require.True(t, strings.Contains(err.Error(), core.ErrUnknownVerificationContract.Error())) // contract wasn't deployed at block #1 yet
 	})
@@ -825,13 +825,13 @@ func TestInvokeVerify(t *testing.T) {
 		var h uint32 = 1
 		sr, err := chain.GetStateModule().GetStateRoot(h)
 		require.NoError(t, err)
-		_, err = c.InvokeContractVerifyWithState(sr.Root, contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
+		_, err = c.InvokeContractVerifyWithState(sr.Root, contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}})
 		require.Error(t, err)
 		require.True(t, strings.Contains(err.Error(), core.ErrUnknownVerificationContract.Error())) // contract wasn't deployed at block #1 yet
 	})
 
 	t.Run("positive, with signer and witness", func(t *testing.T) {
-		res, err := c.InvokeContractVerify(contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}}, transaction.Witness{InvocationScript: []byte{byte(opcode.PUSH1), byte(opcode.RET)}})
+		res, err := c.InvokeContractVerify(contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}}, transaction.Witness{InvocationScript: []byte{byte(opcode.PUSH1), byte(opcode.RET)}})
 		require.NoError(t, err)
 		require.Equal(t, "HALT", res.State)
 		require.Equal(t, 1, len(res.Stack))
@@ -839,12 +839,12 @@ func TestInvokeVerify(t *testing.T) {
 	})
 
 	t.Run("error, invalid witness number", func(t *testing.T) {
-		_, err := c.InvokeContractVerify(contract, smartcontract.Params{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}}, transaction.Witness{InvocationScript: []byte{byte(opcode.PUSH1), byte(opcode.RET)}}, transaction.Witness{InvocationScript: []byte{byte(opcode.RET)}})
+		_, err := c.InvokeContractVerify(contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: testchain.PrivateKeyByID(0).PublicKey().GetScriptHash()}}, transaction.Witness{InvocationScript: []byte{byte(opcode.PUSH1), byte(opcode.RET)}}, transaction.Witness{InvocationScript: []byte{byte(opcode.RET)}})
 		require.Error(t, err)
 	})
 
 	t.Run("false", func(t *testing.T) {
-		res, err := c.InvokeContractVerify(contract, smartcontract.Params{}, []transaction.Signer{{Account: util.Uint160{}}})
+		res, err := c.InvokeContractVerify(contract, []smartcontract.Parameter{}, []transaction.Signer{{Account: util.Uint160{}}})
 		require.NoError(t, err)
 		require.Equal(t, "HALT", res.State)
 		require.Equal(t, 1, len(res.Stack))
@@ -1280,7 +1280,7 @@ func TestClient_InvokeAndPackIteratorResults(t *testing.T) {
 	require.NoError(t, err)
 
 	t.Run("default max items constraint", func(t *testing.T) {
-		res, err := c.InvokeAndPackIteratorResults(storageHash, "iterateOverValues", []smartcontract.Parameter{}, nil)
+		res, err := c.InvokeAndPackIteratorResults(storageHash, "iterateOverValues", []smartcontract.Parameter{}, nil) //nolint:staticcheck // SA1019: c.InvokeAndPackIteratorResults is deprecated
 		require.NoError(t, err)
 		require.Equal(t, vmstate.Halt.String(), res.State)
 		require.Equal(t, 1, len(res.Stack))
@@ -1296,7 +1296,7 @@ func TestClient_InvokeAndPackIteratorResults(t *testing.T) {
 	})
 	t.Run("custom max items constraint", func(t *testing.T) {
 		max := 123
-		res, err := c.InvokeAndPackIteratorResults(storageHash, "iterateOverValues", []smartcontract.Parameter{}, nil, max)
+		res, err := c.InvokeAndPackIteratorResults(storageHash, "iterateOverValues", []smartcontract.Parameter{}, nil, max) //nolint:staticcheck // SA1019: c.InvokeAndPackIteratorResults is deprecated
 		require.NoError(t, err)
 		require.Equal(t, vmstate.Halt.String(), res.State)
 		require.Equal(t, 1, len(res.Stack))

pkg/smartcontract/doc.go

@@ -1,8 +1,10 @@
 /*
-Package smartcontract contains functions to deal with widely used scripts.
+Package smartcontract contains functions to deal with widely used scripts and NEP-14 Parameters.
 Neo is all about various executed code, verifications and executions of
-transactions need some NeoVM code and this package simplifies creating it
+transactions need NeoVM code and this package simplifies creating it
 for common tasks like multisignature verification scripts or transaction
-entry scripts that call previously deployed contracts.
+entry scripts that call previously deployed contracts. Another problem related
+to scripts and invocations is that RPC invocations use JSONized NEP-14
+parameters, so this package provides types and methods to deal with that too.
 */
 package smartcontract

pkg/smartcontract/entry.go

@@ -18,19 +18,10 @@ import (
 // processed this way (and this number can't exceed VM limits), the result of the
 // script is an array containing extracted value elements. This script can be useful
 // for interactions with RPC server that have iterator sessions disabled.
-func CreateCallAndUnwrapIteratorScript(contract util.Uint160, operation string, params []Parameter, maxIteratorResultItems int) ([]byte, error) {
+func CreateCallAndUnwrapIteratorScript(contract util.Uint160, operation string, maxIteratorResultItems int, params ...interface{}) ([]byte, error) {
 	script := io.NewBufBinWriter()
 	emit.Int(script.BinWriter, int64(maxIteratorResultItems))
-	// Pack arguments for System.Contract.Call.
+	emit.AppCall(script.BinWriter, contract, operation, callflag.All, params...) // The System.Contract.Call itself, it will push Iterator on estack.
-	arr, err := ExpandParameterToEmitable(Parameter{
-		Type:  ArrayType,
-		Value: params,
-	})
-	if err != nil {
-		return nil, fmt.Errorf("expanding params to emitable: %w", err)
-	}
-	emit.Array(script.BinWriter, arr.([]interface{})...)
-	emit.AppCallNoArgs(script.BinWriter, contract, operation, callflag.All) // The System.Contract.Call itself, it will push Iterator on estack.
 	emit.Opcodes(script.BinWriter, opcode.NEWARRAY0)                             // Push new empty array to estack. This array will store iterator's elements.
 
 	// Start the iterator traversal cycle.

pkg/smartcontract/parameter.go

@@ -3,19 +3,16 @@ package smartcontract
 import (
 	"bytes"
 	"encoding/base64"
-	"encoding/binary"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"math/big"
-	"math/bits"
 	"os"
 	"strings"
 	"unicode/utf8"
 
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
-	"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 )
@@ -194,123 +191,6 @@ func (p *Parameter) UnmarshalJSON(data []byte) (err error) {
 	return
 }
 
-// Params is an array of Parameter (TODO: drop it?).
-type Params []Parameter
-
-// TryParseArray converts an array of Parameter into an array of more appropriate things.
-func (p Params) TryParseArray(vals ...interface{}) error {
-	var (
-		err error
-		i   int
-		par Parameter
-	)
-	if len(p) != len(vals) {
-		return errors.New("receiver array doesn't fit the Params length")
-	}
-	for i, par = range p {
-		if err = par.TryParse(vals[i]); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// TryParse converts one Parameter into something more appropriate.
-func (p Parameter) TryParse(dest interface{}) error {
-	var (
-		err  error
-		ok   bool
-		data []byte
-	)
-	switch p.Type {
-	case ByteArrayType:
-		if data, ok = p.Value.([]byte); !ok {
-			return fmt.Errorf("failed to cast %s to []byte", p.Value)
-		}
-		switch dest := dest.(type) {
-		case *util.Uint160:
-			if *dest, err = util.Uint160DecodeBytesBE(data); err != nil {
-				return err
-			}
-			return nil
-		case *[]byte:
-			*dest = data
-			return nil
-		case *util.Uint256:
-			if *dest, err = util.Uint256DecodeBytesLE(data); err != nil {
-				return err
-			}
-			return nil
-		case **big.Int:
-			*dest = bigint.FromBytes(data)
-			return nil
-		case *int64, *int32, *int16, *int8, *int, *uint64, *uint32, *uint16, *uint8, *uint:
-			var size int
-			switch dest.(type) {
-			case *int64, *uint64:
-				size = 64
-			case *int32, *uint32:
-				size = 32
-			case *int16, *uint16:
-				size = 16
-			case *int8, *uint8:
-				size = 8
-			case *int, *uint:
-				size = bits.UintSize
-			}
-
-			i, err := bytesToUint64(data, size)
-			if err != nil {
-				return err
-			}
-
-			switch dest := dest.(type) {
-			case *int64:
-				*dest = int64(i)
-			case *int32:
-				*dest = int32(i)
-			case *int16:
-				*dest = int16(i)
-			case *int8:
-				*dest = int8(i)
-			case *int:
-				*dest = int(i)
-			case *uint64:
-				*dest = i
-			case *uint32:
-				*dest = uint32(i)
-			case *uint16:
-				*dest = uint16(i)
-			case *uint8:
-				*dest = uint8(i)
-			case *uint:
-				*dest = uint(i)
-			}
-		case *string:
-			*dest = string(data)
-			return nil
-		default:
-			return fmt.Errorf("cannot cast param of type %s to type %s", p.Type, dest)
-		}
-	default:
-		return errors.New("cannot define param type")
-	}
-	return nil
-}
-
-func bytesToUint64(b []byte, size int) (uint64, error) {
-	var length = size / 8
-	if len(b) > length {
-		return 0, fmt.Errorf("input doesn't fit into %d bits", size)
-	}
-	if len(b) < length {
-		data := make([]byte, length)
-		copy(data, b)
-		return binary.LittleEndian.Uint64(data), nil
-	}
-	return binary.LittleEndian.Uint64(b), nil
-}
-
 // NewParameterFromString returns a new Parameter initialized from the given
 // string in neo-go-specific format. It is intended to be used in user-facing
 // interfaces and has some heuristics in it to simplify parameter passing. The exact
@@ -375,6 +255,111 @@ func NewParameterFromString(in string) (*Parameter, error) {
 	return res, nil
 }
 
+// NewParameterFromValue infers Parameter type from the value given and adjusts
+// the value if needed. It does not copy the value if it can avoid doing so. All
+// regular integers, util.*, keys.PublicKey*, string and bool types are supported,
+// slice of byte slices is accepted and converted as well.
+func NewParameterFromValue(value interface{}) (Parameter, error) {
+	var result = Parameter{
+		Value: value,
+	}
+
+	switch v := value.(type) {
+	case []byte:
+		result.Type = ByteArrayType
+	case string:
+		result.Type = StringType
+	case bool:
+		result.Type = BoolType
+	case *big.Int:
+		result.Type = IntegerType
+	case int8:
+		result.Type = IntegerType
+		result.Value = big.NewInt(int64(v))
+	case byte:
+		result.Type = IntegerType
+		result.Value = big.NewInt(int64(v))
+	case int16:
+		result.Type = IntegerType
+		result.Value = big.NewInt(int64(v))
+	case uint16:
+		result.Type = IntegerType
+		result.Value = big.NewInt(int64(v))
+	case int32:
+		result.Type = IntegerType
+		result.Value = big.NewInt(int64(v))
+	case uint32:
+		result.Type = IntegerType
+		result.Value = big.NewInt(int64(v))
+	case int:
+		result.Type = IntegerType
+		result.Value = big.NewInt(int64(v))
+	case uint:
+		result.Type = IntegerType
+		result.Value = new(big.Int).SetUint64(uint64(v))
+	case int64:
+		result.Type = IntegerType
+		result.Value = big.NewInt(v)
+	case uint64:
+		result.Type = IntegerType
+		result.Value = new(big.Int).SetUint64(v)
+	case util.Uint160:
+		result.Type = Hash160Type
+	case util.Uint256:
+		result.Type = Hash256Type
+	case keys.PublicKey:
+		return NewParameterFromValue(&v)
+	case *keys.PublicKey:
+		result.Type = PublicKeyType
+		result.Value = v.Bytes()
+	case [][]byte:
+		arr := make([]Parameter, 0, len(v))
+		for i := range v {
+			// We know the type exactly, so error is not possible.
+			elem, _ := NewParameterFromValue(v[i])
+			arr = append(arr, elem)
+		}
+		result.Type = ArrayType
+		result.Value = arr
+	case []*keys.PublicKey:
+		return NewParameterFromValue(keys.PublicKeys(v))
+	case keys.PublicKeys:
+		arr := make([]Parameter, 0, len(v))
+		for i := range v {
+			// We know the type exactly, so error is not possible.
+			elem, _ := NewParameterFromValue(v[i])
+			arr = append(arr, elem)
+		}
+		result.Type = ArrayType
+		result.Value = arr
+	case []interface{}:
+		arr, err := NewParametersFromValues(v...)
+		if err != nil {
+			return result, err
+		}
+		result.Type = ArrayType
+		result.Value = arr
+	default:
+		return result, fmt.Errorf("unsupported parameter %T", value)
+	}
+
+	return result, nil
+}
+
+// NewParametersFromValues is similar to NewParameterFromValue except that it
+// works with multiple values and returns a simple slice of Parameter.
+func NewParametersFromValues(values ...interface{}) ([]Parameter, error) {
+	res := make([]Parameter, 0, len(values))
+	for i := range values {
+		elem, err := NewParameterFromValue(values[i])
+		if err != nil {
+			return nil, err
+		}
+		res = append(res, elem)
+	}
+	return res, nil
+}
+
 // ExpandParameterToEmitable converts a parameter to a type which can be handled as
 // an array item by emit.Array. It correlates with the way an RPC server handles
 // FuncParams for invoke* calls inside the request.ExpandArrayIntoScript function.

pkg/smartcontract/parameter_test.go

@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"math"
 	"math/big"
-	"reflect"
 	"strings"
 	"testing"
 
@@ -341,89 +340,6 @@ func TestParam_UnmarshalJSON(t *testing.T) {
 	}
 }
 
-var tryParseTestCases = []struct {
-	input    interface{}
-	expected interface{}
-}{
-	{
-		input: []byte{
-			0x0b, 0xcd, 0x29, 0x78, 0x63, 0x4d, 0x96, 0x1c, 0x24, 0xf5,
-			0xae, 0xa0, 0x80, 0x22, 0x97, 0xff, 0x12, 0x87, 0x24, 0xd6,
-		},
-		expected: util.Uint160{
-			0x0b, 0xcd, 0x29, 0x78, 0x63, 0x4d, 0x96, 0x1c, 0x24, 0xf5,
-			0xae, 0xa0, 0x80, 0x22, 0x97, 0xff, 0x12, 0x87, 0x24, 0xd6,
-		},
-	},
-	{
-		input: []byte{
-			0xf0, 0x37, 0x30, 0x8f, 0xa0, 0xab, 0x18, 0x15,
-			0x5b, 0xcc, 0xfc, 0x08, 0x48, 0x54, 0x68, 0xc1,
-			0x12, 0x40, 0x9e, 0xa5, 0x06, 0x45, 0x95, 0x69,
-			0x9e, 0x98, 0xc5, 0x45, 0xf2, 0x45, 0xf3, 0x2d,
-		},
-		expected: util.Uint256{
-			0x2d, 0xf3, 0x45, 0xf2, 0x45, 0xc5, 0x98, 0x9e,
-			0x69, 0x95, 0x45, 0x06, 0xa5, 0x9e, 0x40, 0x12,
-			0xc1, 0x68, 0x54, 0x48, 0x08, 0xfc, 0xcc, 0x5b,
-			0x15, 0x18, 0xab, 0xa0, 0x8f, 0x30, 0x37, 0xf0,
-		},
-	},
-	{
-		input:    []byte{0, 1, 2, 3, 4, 9, 8, 6},
-		expected: []byte{0, 1, 2, 3, 4, 9, 8, 6},
-	},
-	{
-		input:    []byte{0x63, 0x78, 0x29, 0xcd, 0x0b},
-		expected: int64(50686687331),
-	},
-	{
-		input:    []byte{0x63, 0x78, 0x29, 0xcd, 0x0b},
-		expected: big.NewInt(50686687331),
-	},
-	{
-		input:    []byte("this is a test string"),
-		expected: "this is a test string",
-	},
-}
-
-func TestParam_TryParse(t *testing.T) {
-	for _, tc := range tryParseTestCases {
-		t.Run(reflect.TypeOf(tc.expected).String(), func(t *testing.T) {
-			input := Parameter{
-				Type:  ByteArrayType,
-				Value: tc.input,
-			}
-
-			val := reflect.New(reflect.TypeOf(tc.expected))
-			assert.NoError(t, input.TryParse(val.Interface()))
-			assert.Equal(t, tc.expected, val.Elem().Interface())
-		})
-	}
-
-	t.Run("[]Uint160", func(t *testing.T) {
-		exp1 := util.Uint160{1, 2, 3, 4, 5}
-		exp2 := util.Uint160{9, 8, 7, 6, 5}
-
-		params := Params{
-			{
-				Type:  ByteArrayType,
-				Value: exp1.BytesBE(),
-			},
-			{
-				Type:  ByteArrayType,
-				Value: exp2.BytesBE(),
-			},
-		}
-
-		var out1, out2 util.Uint160
-
-		assert.NoError(t, params.TryParseArray(&out1, &out2))
-		assert.Equal(t, exp1, out1)
-		assert.Equal(t, exp2, out2)
-	})
-}
-
 func TestParamType_String(t *testing.T) {
 	types := []ParamType{
 		SignatureType,
@@ -611,3 +527,185 @@ func TestExpandParameterToEmitable(t *testing.T) {
 		require.Error(t, err)
 	}
 }
+
+func TestParameterFromValue(t *testing.T) {
+	pk1, _ := keys.NewPrivateKey()
+	pk2, _ := keys.NewPrivateKey()
+	items := []struct {
+		value   interface{}
+		expType ParamType
+		expVal  interface{}
+	}{
+		{
+			value:   []byte{1, 2, 3},
+			expType: ByteArrayType,
+			expVal:  []byte{1, 2, 3},
+		},
+		{
+			value:   "hello world",
+			expType: StringType,
+			expVal:  "hello world",
+		},
+		{
+			value:   false,
+			expType: BoolType,
+			expVal:  false,
+		},
+		{
+			value:   true,
+			expType: BoolType,
+			expVal:  true,
+		},
+		{
+			value:   big.NewInt(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   byte(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   int8(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   uint8(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   int16(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   uint16(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   int32(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   uint32(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   100,
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   uint(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   int64(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   uint64(100),
+			expType: IntegerType,
+			expVal:  big.NewInt(100),
+		},
+		{
+			value:   util.Uint160{1, 2, 3},
+			expType: Hash160Type,
+			expVal:  util.Uint160{1, 2, 3},
+		},
+		{
+			value:   util.Uint256{3, 2, 1},
+			expType: Hash256Type,
+			expVal:  util.Uint256{3, 2, 1},
+		},
+		{
+			value:   pk1.PublicKey(),
+			expType: PublicKeyType,
+			expVal:  pk1.PublicKey().Bytes(),
+		},
+		{
+			value:   *pk2.PublicKey(),
+			expType: PublicKeyType,
+			expVal:  pk2.PublicKey().Bytes(),
+		},
+		{
+			value:   [][]byte{{1, 2, 3}, {3, 2, 1}},
+			expType: ArrayType,
+			expVal:  []Parameter{{ByteArrayType, []byte{1, 2, 3}}, {ByteArrayType, []byte{3, 2, 1}}},
+		},
+		{
+			value:   []*keys.PublicKey{pk1.PublicKey(), pk2.PublicKey()},
+			expType: ArrayType,
+			expVal: []Parameter{{
+				Type:  PublicKeyType,
+				Value: pk1.PublicKey().Bytes(),
+			}, {
+				Type:  PublicKeyType,
+				Value: pk2.PublicKey().Bytes(),
+			}},
+		},
+		{
+			value:   keys.PublicKeys{pk1.PublicKey(), pk2.PublicKey()},
+			expType: ArrayType,
+			expVal: []Parameter{{
+				Type:  PublicKeyType,
+				Value: pk1.PublicKey().Bytes(),
+			}, {
+				Type:  PublicKeyType,
+				Value: pk2.PublicKey().Bytes(),
+			}},
+		},
+		{
+			value:   []interface{}{-42, "random", []byte{1, 2, 3}},
+			expType: ArrayType,
+			expVal: []Parameter{{
+				Type:  IntegerType,
+				Value: big.NewInt(-42),
+			}, {
+				Type:  StringType,
+				Value: "random",
+			}, {
+				Type:  ByteArrayType,
+				Value: []byte{1, 2, 3},
+			}},
+		},
+	}
+
+	for _, item := range items {
+		t.Run(item.expType.String()+" to stack parameter", func(t *testing.T) {
+			res, err := NewParameterFromValue(item.value)
+			require.NoError(t, err)
+			require.Equal(t, item.expType, res.Type)
+			require.Equal(t, item.expVal, res.Value)
+		})
+	}
+	_, err := NewParameterFromValue(make(map[string]int))
+	require.Error(t, err)
+	_, err = NewParameterFromValue([]interface{}{1, 2, make(map[string]int)})
+	require.Error(t, err)
+}
+
+func TestParametersFromValues(t *testing.T) {
+	res, err := NewParametersFromValues(42, "some", []byte{3, 2, 1})
+	require.NoError(t, err)
+	require.Equal(t, []Parameter{{
+		Type:  IntegerType,
+		Value: big.NewInt(42),
+	}, {
+		Type:  StringType,
+		Value: "some",
+	}, {
+		Type:  ByteArrayType,
+		Value: []byte{3, 2, 1},
+	}}, res)
+	_, err = NewParametersFromValues(42, make(map[int]int), []byte{3, 2, 1})
+	require.Error(t, err)
+}