42 lines
1 KiB
Go
42 lines
1 KiB
Go
package callback
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import (
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"errors"
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"github.com/nspcc-dev/neo-go/pkg/core/interop"
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"github.com/nspcc-dev/neo-go/pkg/vm"
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"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
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)
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// SyscallCallback represents callback for a syscall.
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type SyscallCallback struct {
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desc *interop.Function
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}
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var _ Callback = (*SyscallCallback)(nil)
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// ArgCount implements Callback interface.
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func (p *SyscallCallback) ArgCount() int {
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return p.desc.ParamCount
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}
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// LoadContext implements Callback interface.
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func (p *SyscallCallback) LoadContext(v *vm.VM, args []stackitem.Item) {
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for i := len(args) - 1; i >= 0; i-- {
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v.Estack().PushVal(args[i])
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}
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}
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// CreateFromSyscall creates callback from syscall.
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func CreateFromSyscall(ic *interop.Context) error {
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id := uint32(ic.VM.Estack().Pop().BigInt().Int64())
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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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if f.DisallowCallback {
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return errors.New("syscall is not allowed to be used in a callback")
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}
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ic.VM.Estack().PushVal(stackitem.NewInterop(&SyscallCallback{f}))
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return nil
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}
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