neo-go/pkg/vm/stack/invocationstack.go
decentralisedkev c1b6738bdb
VM: Add basic vm (#166)
* VM:Add abstract stack item

* VM: Add stackItems; Array, Boolean, Int and ByteArray

* VM: Add tests for stack item

* VM: first pass at Random Access Stack object

* VM: Add Sub, Mul, Mod LSH, RSH

* VM: moved test helper functions into separate file

* VM: removed helper functions from stack_test.go

* Add conversions for bytearray and Int stack items

* Add instructions file for vm

* - Add guide to stack readme
- Add testReadInt64

* Add Builder

* Refactor Int, Boolean, ByteArray conversion

* Add Context stack Item

* Add Invocation stack - convenience RAS

* rename testhelper to test_helper

* Move opcode file

* - Add `Add` OpCode
- Add Opcode Function map

* - Add test for math `Add` opcode
- basic opcode execution

* Add popTwoIntegers convenience func

* Add `SUB` Opcode

* Export Context Read methods
- Return errors where failable

* - Add `Op` to handleOP func signature
- Add PushNBytes OPcode

* remove error on NewBoolean
- Expose underlying with Getter on Boolean StackItem
- Add Equals method for ByteArray

* Make Next() method on Context failable, refactor peekContext and Peek

* Add ExecuteOp, Step and Run methods on the VM

* Add Equal Opcode

* Add THROWIFNOT Opcode

* Add RET Opcode

* Refactor PushNBytes Opcode

* refactor Add, Sub to return VMSTATE
add popTwoByteArrays helper function

* Add basic tests for vm

* clarify vm states

* Add astack

* [VM]

Pass ResultStack to the opcode handlers

* [VM]

refactor handlers to have rstack as argument

* [Stack]

- Change RemoveCurrentContext for PopCurrentContext
- Add CopTo method to stack

* [VM]

Add Result stack Len check in simple run test

* [VM] fix typo

* [Peer/Stall]

Change seconds to milliseconds in test
2019-03-18 21:40:21 +00:00

61 lines
1.5 KiB
Go

package stack
import "errors"
// Invocation embeds a Random Access stack
// Providing helper methods for the context object
type Invocation struct{ RandomAccess }
//NewInvocation will return a new
// Invocation stack
func NewInvocation() *Invocation {
return &Invocation{
RandomAccess{
vals: make([]Item, 0, StackAverageSize),
},
}
}
func (i *Invocation) peekContext(n uint16) (*Context, error) {
item, err := i.Peek(n)
if err != nil {
return nil, err
}
return item.Context()
}
// CurrentContext returns the current context on the invocation stack
func (i *Invocation) CurrentContext() (*Context, error) {
return i.peekContext(0)
}
// PopCurrentContext Pops a context item from the top of the stack
func (i *Invocation) PopCurrentContext() (*Context, error) {
item, err := i.Pop()
if err != nil {
return nil, err
}
ctx, err := item.Context()
if err != nil {
return nil, err
}
return ctx, err
}
// CallingContext will return the cntext item
// that will be called next.
func (i *Invocation) CallingContext() (*Context, error) {
if i.Len() < 1 {
return nil, errors.New("Length of invocation stack is < 1, no calling context")
}
return i.peekContext(1)
}
// EntryContext will return the context item that
// started the program
func (i *Invocation) EntryContext() (*Context, error) {
// firstItemIndex refers to the first item that was popped on the stack
firstItemIndex := uint16(i.Len() - 1) // N.B. if this overflows because len is zero, then an error will be returned
return i.peekContext(firstItemIndex)
}