2808f6857d
Functions are usually immediately replaced (and it's OK for them to be nil, searching through an array with length of zero is fine), Notifications are usually appended to (and are absolutely useless in verification contexts).
286 lines
8.4 KiB
Go
286 lines
8.4 KiB
Go
package interop
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"sort"
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"strings"
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"github.com/nspcc-dev/neo-go/pkg/core/block"
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"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
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"github.com/nspcc-dev/neo-go/pkg/core/dao"
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"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
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"github.com/nspcc-dev/neo-go/pkg/core/state"
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"github.com/nspcc-dev/neo-go/pkg/core/transaction"
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"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
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"github.com/nspcc-dev/neo-go/pkg/io"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/nef"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
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"github.com/nspcc-dev/neo-go/pkg/util"
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"github.com/nspcc-dev/neo-go/pkg/vm"
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"github.com/nspcc-dev/neo-go/pkg/vm/emit"
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"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
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"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
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"go.uber.org/zap"
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)
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const (
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// DefaultBaseExecFee specifies default multiplier for opcode and syscall prices.
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DefaultBaseExecFee = 30
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)
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// Context represents context in which interops are executed.
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type Context struct {
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Chain blockchainer.Blockchainer
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Container hash.Hashable
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Network uint32
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Natives []Contract
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Trigger trigger.Type
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Block *block.Block
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NonceData [16]byte
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Tx *transaction.Transaction
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DAO dao.DAO
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Notifications []state.NotificationEvent
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Log *zap.Logger
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VM *vm.VM
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Functions []Function
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getContract func(dao.DAO, util.Uint160) (*state.Contract, error)
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baseExecFee int64
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}
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// NewContext returns new interop context.
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func NewContext(trigger trigger.Type, bc blockchainer.Blockchainer, d dao.DAO,
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getContract func(dao.DAO, util.Uint160) (*state.Contract, error), natives []Contract,
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block *block.Block, tx *transaction.Transaction, log *zap.Logger) *Context {
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baseExecFee := int64(DefaultBaseExecFee)
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dao := d.GetWrapped()
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if bc != nil && (block == nil || block.Index != 0) {
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baseExecFee = bc.GetPolicer().GetBaseExecFee()
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}
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return &Context{
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Chain: bc,
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Network: uint32(bc.GetConfig().Magic),
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Natives: natives,
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Trigger: trigger,
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Block: block,
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Tx: tx,
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DAO: dao,
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Log: log,
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getContract: getContract,
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baseExecFee: baseExecFee,
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}
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}
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// InitNonceData initializes nonce to be used in `GetRandom` calculations.
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func (ic *Context) InitNonceData() {
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if tx, ok := ic.Container.(*transaction.Transaction); ok {
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copy(ic.NonceData[:], tx.Hash().BytesBE())
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}
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if ic.Block != nil {
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nonce := ic.Block.Nonce
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nonce ^= binary.LittleEndian.Uint64(ic.NonceData[:])
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binary.LittleEndian.PutUint64(ic.NonceData[:], nonce)
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}
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}
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// Function binds function name, id with the function itself and price,
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// it's supposed to be inited once for all interopContexts, so it doesn't use
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// vm.InteropFuncPrice directly.
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type Function struct {
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ID uint32
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Name string
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Func func(*Context) error
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// ParamCount is a number of function parameters.
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ParamCount int
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Price int64
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// RequiredFlags is a set of flags which must be set during script invocations.
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// Default value is NoneFlag i.e. no flags are required.
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RequiredFlags callflag.CallFlag
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}
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// Method is a signature for a native method.
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type Method = func(ic *Context, args []stackitem.Item) stackitem.Item
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// MethodAndPrice is a native-contract method descriptor.
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type MethodAndPrice struct {
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Func Method
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MD *manifest.Method
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CPUFee int64
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StorageFee int64
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SyscallOffset int
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RequiredFlags callflag.CallFlag
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}
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// Contract is an interface for all native contracts.
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type Contract interface {
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Initialize(*Context) error
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Metadata() *ContractMD
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OnPersist(*Context) error
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PostPersist(*Context) error
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}
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// ContractMD represents native contract instance.
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type ContractMD struct {
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state.NativeContract
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Name string
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Methods []MethodAndPrice
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}
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// NewContractMD returns Contract with the specified list of methods.
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func NewContractMD(name string, id int32) *ContractMD {
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c := &ContractMD{Name: name}
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c.ID = id
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// NEF is now stored in contract state and affects state dump.
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// Therefore values are taken from C# node.
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c.NEF.Header.Compiler = "neo-core-v3.0"
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c.NEF.Header.Magic = nef.Magic
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c.Hash = state.CreateContractHash(util.Uint160{}, 0, c.Name)
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c.Manifest = *manifest.DefaultManifest(name)
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return c
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}
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// UpdateHash creates native contract script and updates hash.
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func (c *ContractMD) UpdateHash() {
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w := io.NewBufBinWriter()
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for i := range c.Methods {
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offset := w.Len()
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c.Methods[i].MD.Offset = offset
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c.Manifest.ABI.Methods[i].Offset = offset
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emit.Int(w.BinWriter, 0)
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c.Methods[i].SyscallOffset = w.Len()
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emit.Syscall(w.BinWriter, interopnames.SystemContractCallNative)
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emit.Opcodes(w.BinWriter, opcode.RET)
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}
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if w.Err != nil {
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panic(fmt.Errorf("can't create native contract script: %w", w.Err))
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}
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c.NEF.Script = w.Bytes()
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c.NEF.Checksum = c.NEF.CalculateChecksum()
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}
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// AddMethod adds new method to a native contract.
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func (c *ContractMD) AddMethod(md *MethodAndPrice, desc *manifest.Method) {
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md.MD = desc
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desc.Safe = md.RequiredFlags&(callflag.All^callflag.ReadOnly) == 0
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index := sort.Search(len(c.Manifest.ABI.Methods), func(i int) bool {
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md := c.Manifest.ABI.Methods[i]
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if md.Name != desc.Name {
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return md.Name >= desc.Name
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}
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return len(md.Parameters) > len(desc.Parameters)
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})
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c.Manifest.ABI.Methods = append(c.Manifest.ABI.Methods, manifest.Method{})
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copy(c.Manifest.ABI.Methods[index+1:], c.Manifest.ABI.Methods[index:])
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c.Manifest.ABI.Methods[index] = *desc
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// Cache follows the same order.
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c.Methods = append(c.Methods, MethodAndPrice{})
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copy(c.Methods[index+1:], c.Methods[index:])
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c.Methods[index] = *md
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}
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// GetMethodByOffset returns with the provided offset.
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// Offset is offset of `System.Contract.CallNative` syscall.
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func (c *ContractMD) GetMethodByOffset(offset int) (MethodAndPrice, bool) {
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for k := range c.Methods {
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if c.Methods[k].SyscallOffset == offset {
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return c.Methods[k], true
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}
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}
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return MethodAndPrice{}, false
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}
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// GetMethod returns method `name` with specified number of parameters.
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func (c *ContractMD) GetMethod(name string, paramCount int) (MethodAndPrice, bool) {
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index := sort.Search(len(c.Methods), func(i int) bool {
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md := c.Methods[i]
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res := strings.Compare(name, md.MD.Name)
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switch res {
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case -1, 1:
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return res == -1
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default:
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return paramCount <= len(md.MD.Parameters)
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}
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})
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if index < len(c.Methods) {
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md := c.Methods[index]
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if md.MD.Name == name && (paramCount == -1 || len(md.MD.Parameters) == paramCount) {
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return md, true
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}
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}
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return MethodAndPrice{}, false
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}
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// AddEvent adds new event to a native contract.
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func (c *ContractMD) AddEvent(name string, ps ...manifest.Parameter) {
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c.Manifest.ABI.Events = append(c.Manifest.ABI.Events, manifest.Event{
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Name: name,
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Parameters: ps,
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})
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}
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// IsActive returns true iff the contract was deployed by the specified height.
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func (c *ContractMD) IsActive(height uint32) bool {
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history := c.UpdateHistory
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return len(history) != 0 && history[0] <= height
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}
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// Sort sorts interop functions by id.
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func Sort(fs []Function) {
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sort.Slice(fs, func(i, j int) bool { return fs[i].ID < fs[j].ID })
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}
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// GetContract returns contract by its hash in current interop context.
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func (ic *Context) GetContract(hash util.Uint160) (*state.Contract, error) {
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return ic.getContract(ic.DAO, hash)
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}
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// GetFunction returns metadata for interop with the specified id.
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func (ic *Context) GetFunction(id uint32) *Function {
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n := sort.Search(len(ic.Functions), func(i int) bool {
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return ic.Functions[i].ID >= id
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})
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if n < len(ic.Functions) && ic.Functions[n].ID == id {
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return &ic.Functions[n]
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}
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return nil
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}
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// BaseExecFee represents factor to multiply syscall prices with.
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func (ic *Context) BaseExecFee() int64 {
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return ic.baseExecFee
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}
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// SyscallHandler handles syscall with id.
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func (ic *Context) SyscallHandler(_ *vm.VM, id uint32) error {
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f := ic.GetFunction(id)
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if f == nil {
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return errors.New("syscall not found")
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}
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cf := ic.VM.Context().GetCallFlags()
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if !cf.Has(f.RequiredFlags) {
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return fmt.Errorf("missing call flags: %05b vs %05b", cf, f.RequiredFlags)
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}
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if !ic.VM.AddGas(f.Price * ic.BaseExecFee()) {
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return errors.New("insufficient amount of gas")
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}
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return f.Func(ic)
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}
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// SpawnVM spawns new VM with the specified gas limit and set context.VM field.
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func (ic *Context) SpawnVM() *vm.VM {
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v := vm.NewWithTrigger(ic.Trigger)
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v.GasLimit = -1
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v.SyscallHandler = ic.SyscallHandler
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ic.VM = v
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return v
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}
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