neoneo-go/pkg/core/interop/storage/basic.go

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package storage
import (
"errors"
"fmt"
"github.com/nspcc-dev/neo-go/pkg/config/limits"
"github.com/nspcc-dev/neo-go/pkg/core/interop"
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
var (
// ErrGasLimitExceeded is returned from interops when there is not enough
// GAS left in the execution context to complete the action.
ErrGasLimitExceeded = errors.New("gas limit exceeded")
errFindInvalidOptions = errors.New("invalid Find options")
)
// Context contains contract ID and read/write flag, it's used as
// a context for storage manipulation functions.
type Context struct {
ID int32
ReadOnly bool
}
// storageDelete deletes stored key-value pair.
func Delete(ic *interop.Context) error {
stcInterface := ic.VM.Estack().Pop().Value()
stc, ok := stcInterface.(*Context)
if !ok {
return fmt.Errorf("%T is not a storage.Context", stcInterface)
}
if stc.ReadOnly {
return errors.New("storage.Context is read only")
}
key := ic.VM.Estack().Pop().Bytes()
ic.DAO.DeleteStorageItem(stc.ID, key)
return nil
}
// Get returns stored key-value pair.
func Get(ic *interop.Context) error {
stcInterface := ic.VM.Estack().Pop().Value()
stc, ok := stcInterface.(*Context)
if !ok {
return fmt.Errorf("%T is not a storage.Context", stcInterface)
}
key := ic.VM.Estack().Pop().Bytes()
si := ic.DAO.GetStorageItem(stc.ID, key)
if si != nil {
ic.VM.Estack().PushItem(stackitem.NewByteArray([]byte(si)))
} else {
ic.VM.Estack().PushItem(stackitem.Null{})
}
return nil
}
// GetContext returns storage context for the currently executing contract.
func GetContext(ic *interop.Context) error {
return getContextInternal(ic, false)
}
// GetReadOnlyContext returns read-only storage context for the currently executing contract.
func GetReadOnlyContext(ic *interop.Context) error {
return getContextInternal(ic, true)
}
// getContextInternal is internal version of storageGetContext and
// storageGetReadOnlyContext which allows to specify ReadOnly context flag.
func getContextInternal(ic *interop.Context, isReadOnly bool) error {
contract, err := ic.GetContract(ic.VM.GetCurrentScriptHash())
if err != nil {
return err
}
sc := &Context{
ID: contract.ID,
ReadOnly: isReadOnly,
}
ic.VM.Estack().PushItem(stackitem.NewInterop(sc))
return nil
}
func putWithContext(ic *interop.Context, stc *Context, key []byte, value []byte) error {
if len(key) > limits.MaxStorageKeyLen {
return errors.New("key is too big")
}
if len(value) > limits.MaxStorageValueLen {
return errors.New("value is too big")
}
if stc.ReadOnly {
return errors.New("storage.Context is read only")
}
si := ic.DAO.GetStorageItem(stc.ID, key)
sizeInc := len(value)
if si == nil {
sizeInc = len(key) + len(value)
} else if len(value) != 0 {
if len(value) <= len(si) {
sizeInc = (len(value)-1)/4 + 1
} else if len(si) != 0 {
sizeInc = (len(si)-1)/4 + 1 + len(value) - len(si)
}
}
if !ic.VM.AddGas(int64(sizeInc) * ic.BaseStorageFee()) {
return ErrGasLimitExceeded
}
ic.DAO.PutStorageItem(stc.ID, key, value)
return nil
}
// Put puts key-value pair into the storage.
func Put(ic *interop.Context) error {
stcInterface := ic.VM.Estack().Pop().Value()
stc, ok := stcInterface.(*Context)
if !ok {
return fmt.Errorf("%T is not a storage.Context", stcInterface)
}
key := ic.VM.Estack().Pop().Bytes()
value := ic.VM.Estack().Pop().Bytes()
return putWithContext(ic, stc, key, value)
}
// ContextAsReadOnly sets given context to read-only mode.
func ContextAsReadOnly(ic *interop.Context) error {
stcInterface := ic.VM.Estack().Pop().Value()
stc, ok := stcInterface.(*Context)
if !ok {
return fmt.Errorf("%T is not a storage.Context", stcInterface)
}
if !stc.ReadOnly {
stx := &Context{
ID: stc.ID,
ReadOnly: true,
}
stc = stx
}
ic.VM.Estack().PushItem(stackitem.NewInterop(stc))
return nil
}