neoneo-go/pkg/vm/vm_ops_stackmani.go
Roman Khimov 3bc195659a pkg/vm: fix error handling in XDROP()
Found by GolangCI:
  Error return value of ctx.Estack.Remove is not checked (from errcheck)
  nilness: impossible condition: nil != nil (from govet)
2019-08-12 16:40:19 +03:00

300 lines
7.3 KiB
Go

package vm
import (
"math/big"
"github.com/CityOfZion/neo-go/pkg/vm/stack"
)
// Stack Manipulation Opcodes
// PushNBytes will Read N Bytes from the script and push it onto the stack
func PushNBytes(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
val, err := ctx.ReadBytes(int(op))
if err != nil {
return FAULT, err
}
ba := stack.NewByteArray(val)
ctx.Estack.Push(ba)
return NONE, nil
}
// ROLL pops an integer n off of the stack and
// moves the n-item starting from
// the top of the stack onto the top stack item.
// Returns an error if the top stack item is not an
// integer or n-item does not exist.
func ROLL(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
n, err := ctx.Estack.PopInt()
if err != nil {
return FAULT, err
}
nItem, err := ctx.Estack.Remove(uint16(n.Value().Int64()))
if err != nil {
return FAULT, err
}
ctx.Estack.Push(nItem)
return NONE, nil
}
// ROT moves the third top stack item
// onto the top stack item.
// Returns an error if the third top stack item
// does not exist.
func ROT(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Estack.Remove(2)
if err != nil {
return FAULT, err
}
ctx.Estack.Push(item)
return NONE, nil
}
// SWAP swaps the second top stack item with
// the top stack item.
// Returns an error if the second top stack item
// does not exist.
func SWAP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Estack.Remove(1)
if err != nil {
return FAULT, err
}
ctx.Estack.Push(item)
return NONE, nil
}
// TUCK copies the top stack item and
// inserts it before the second top stack item.
// Returns an error if the stack is empty or
// len(stack) is less or equal 2.
func TUCK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Estack.Peek(0)
if err != nil {
return FAULT, err
}
ras, err := ctx.Estack.Insert(2, item)
if err != nil {
return FAULT, err
}
ctx.Estack = *ras
return NONE, nil
}
// DUP duplicates the top stack item.
// Returns an error if stack is empty.
func DUP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Estack.Peek(0)
if err != nil {
return FAULT, err
}
ctx.Estack.Push(item)
return NONE, nil
}
// XSWAP pops an integer n off of the stack and
// swaps the n-item from the stack starting from
// the top of the stack with the top stack item.
func XSWAP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
n, err := ctx.Estack.PopInt()
if err != nil {
return FAULT, err
}
nItem, err := ctx.Estack.Peek(uint16(n.Value().Int64()))
if err != nil {
return FAULT, err
}
item, err := ctx.Estack.Peek(0)
if err != nil {
return FAULT, err
}
if err := ctx.Estack.Set(uint16(n.Value().Int64()), item); err != nil {
return FAULT, err
}
if err := ctx.Estack.Set(0, nItem); err != nil {
return FAULT, err
}
return NONE, nil
}
// DUPFROMALTSTACK duplicates the item on top of alternative stack and
// puts it on top of evaluation stack.
// Returns an error if the alt stack is empty.
func DUPFROMALTSTACK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Astack.Peek(0)
if err != nil {
return FAULT, err
}
ctx.Estack.Push(item)
return NONE, nil
}
// NIP removes the second top stack item.
// Returns error if the stack item contains
// only one element.
func NIP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
_, err := ctx.Estack.Remove(1)
if err != nil {
return FAULT, err
}
return NONE, nil
}
// OVER copies the second-to-top stack item onto the top.
// Returns an error if the stack item contains
// only one element.
func OVER(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Estack.Peek(1)
if err != nil {
return FAULT, err
}
ctx.Estack.Push(item)
return NONE, nil
}
// XTUCK pops an integer n off of the stack and
// inserts the top stack item to the position len(stack)-n in the evaluation stack.
func XTUCK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
n, err := ctx.Estack.PopInt()
if err != nil || n.Value().Int64() < 0 {
return FAULT, err
}
item, err := ctx.Estack.Peek(0)
if err != nil {
return FAULT, err
}
ras, err := ctx.Estack.Insert(uint16(n.Value().Int64()), item)
if err != nil {
return FAULT, err
}
ctx.Estack = *ras
return NONE, nil
}
// TOALTSTACK pops an item off of the evaluation stack and
// pushes it on top of the alternative stack.
// Returns an error if the alternative stack is empty.
func TOALTSTACK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Estack.Pop()
if err != nil {
return FAULT, err
}
ctx.Astack.Push(item)
return NONE, nil
}
// DEPTH puts the number of stack items onto the stack.
func DEPTH(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
l := ctx.Estack.Len()
length, err := stack.NewInt(big.NewInt(int64(l)))
if err != nil {
return FAULT, err
}
ctx.Estack.Push(length)
return NONE, nil
}
// FROMALTSTACK pops an item off of the alternative stack and
// pushes it on top of the evaluation stack.
// Returns an error if the evaluation stack is empty.
func FROMALTSTACK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
item, err := ctx.Astack.Pop()
if err != nil {
return FAULT, err
}
ctx.Estack.Push(item)
return NONE, nil
}
// PICK pops an integer n off of the stack and
// copies the n-item starting from
// the top of the stack onto the top stack item.
// Returns an error if the top stack item is not an
// integer or n-item does not exist.
func PICK(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
n, err := ctx.Estack.PopInt()
if err != nil {
return FAULT, err
}
nItem, err := ctx.Estack.Peek(uint16(n.Value().Int64()))
if err != nil {
return FAULT, err
}
ctx.Estack.Push(nItem)
return NONE, nil
}
// DROP removes the the top stack item.
// Returns error if the operation Pop cannot
// be performed.
func DROP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
_, err := ctx.Estack.Pop()
if err != nil {
return FAULT, err
}
return NONE, nil
}
// XDROP pops an integer n off of the stack and
// removes the n-item from the stack starting from
// the top of the stack.
func XDROP(op stack.Instruction, ctx *stack.Context, istack *stack.Invocation, rstack *stack.RandomAccess) (Vmstate, error) {
n, err := ctx.Estack.PopInt()
if err != nil {
return FAULT, err
}
_, err = ctx.Estack.Remove(uint16(n.Value().Uint64()))
if err != nil {
return FAULT, err
}
return NONE, nil
}