neoneo-go/pkg/vm/interop.go

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package vm
import (
"crypto/sha256"
"encoding/binary"
"errors"
"fmt"
"sort"
)
// InteropFunc allows to hook into the VM.
type InteropFunc func(vm *VM) error
// InteropFuncPrice represents an interop function with a price.
type InteropFuncPrice struct {
Func InteropFunc
Price int
}
// interopIDFuncPrice adds an ID to the InteropFuncPrice.
type interopIDFuncPrice struct {
ID uint32
InteropFuncPrice
}
// InteropGetterFunc is a function that returns an interop function-price
// structure by the given interop ID.
type InteropGetterFunc func(uint32) *InteropFuncPrice
var defaultVMInterops = []interopIDFuncPrice{
{InteropNameToID([]byte("Neo.Runtime.Log")),
InteropFuncPrice{runtimeLog, 1}},
{InteropNameToID([]byte("Neo.Runtime.Notify")),
InteropFuncPrice{runtimeNotify, 1}},
{InteropNameToID([]byte("Neo.Runtime.Serialize")),
InteropFuncPrice{RuntimeSerialize, 1}},
{InteropNameToID([]byte("System.Runtime.Serialize")),
InteropFuncPrice{RuntimeSerialize, 1}},
{InteropNameToID([]byte("Neo.Runtime.Deserialize")),
InteropFuncPrice{RuntimeDeserialize, 1}},
{InteropNameToID([]byte("System.Runtime.Deserialize")),
InteropFuncPrice{RuntimeDeserialize, 1}},
}
func getDefaultVMInterop(id uint32) *InteropFuncPrice {
n := sort.Search(len(defaultVMInterops), func(i int) bool {
return defaultVMInterops[i].ID >= id
})
if n < len(defaultVMInterops) && defaultVMInterops[n].ID == id {
return &defaultVMInterops[n].InteropFuncPrice
}
return nil
}
// InteropNameToID returns an identificator of the method based on its name.
func InteropNameToID(name []byte) uint32 {
h := sha256.Sum256(name)
return binary.LittleEndian.Uint32(h[:4])
}
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// runtimeLog handles the syscall "Neo.Runtime.Log" for printing and logging stuff.
func runtimeLog(vm *VM) error {
item := vm.Estack().Pop()
fmt.Printf("NEO-GO-VM (log) > %s\n", item.Value())
return nil
}
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// runtimeNotify handles the syscall "Neo.Runtime.Notify" for printing and logging stuff.
func runtimeNotify(vm *VM) error {
item := vm.Estack().Pop()
fmt.Printf("NEO-GO-VM (notify) > %s\n", item.Value())
return nil
}
// RuntimeSerialize handles syscalls System.Runtime.Serialize and Neo.Runtime.Serialize.
func RuntimeSerialize(vm *VM) error {
item := vm.Estack().Pop()
data, err := serializeItem(item.value)
if err != nil {
return err
} else if len(data) > MaxItemSize {
return errors.New("too big item")
}
vm.Estack().PushVal(data)
return nil
}
// RuntimeDeserialize handles syscalls System.Runtime.Deserialize and Neo.Runtime.Deserialize.
func RuntimeDeserialize(vm *VM) error {
data := vm.Estack().Pop().Bytes()
item, err := deserializeItem(data)
if err != nil {
return err
}
vm.Estack().Push(&Element{value: item})
return nil
}
// init sorts the global defaultVMInterops value.
func init() {
sort.Slice(defaultVMInterops, func(i, j int) bool {
return defaultVMInterops[i].ID < defaultVMInterops[j].ID
})
}