neoneo-go/pkg/core/interop/callback/callback.go

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package callback
import (
"errors"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/vm"
"github.com/nspcc-dev/neo-go/pkg/vm/emit"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
// Callback is an interface for arbitrary callbacks.
type Callback interface {
// ArgCount returns expected number of arguments.
ArgCount() int
// LoadContext loads context and arguments on stack.
LoadContext(*vm.VM, []stackitem.Item)
}
// Invoke invokes provided callback.
func Invoke(ic *interop.Context, v *vm.VM) error {
cb := v.Estack().Pop().Interop().Value().(Callback)
args := v.Estack().Pop().Array()
if cb.ArgCount() != len(args) {
return errors.New("invalid argument count")
}
cb.LoadContext(v, args)
switch t := cb.(type) {
case *MethodCallback:
id := emit.InteropNameToID([]byte("System.Contract.Call"))
return ic.SyscallHandler(v, id)
case *SyscallCallback:
return ic.SyscallHandler(v, t.desc.ID)
default:
return nil
}
}