forked from TrueCloudLab/neoneo-go
278 lines
8.2 KiB
Go
278 lines
8.2 KiB
Go
/*
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Package unwrap provides a set of proxy methods to process invocation results.
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Functions implemented there are intended to be used as wrappers for other
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functions that return (*result.Invoke, error) pair (of which there are many).
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These functions will check for error, check for VM state, check the number
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of results, cast them to appropriate type (if everything is OK) and then
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return a result or error. They're mostly useful for other higher-level
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contract-specific packages.
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*/
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package unwrap
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import (
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"crypto/elliptic"
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"errors"
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"fmt"
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"math/big"
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"unicode/utf8"
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"github.com/google/uuid"
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"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
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"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
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"github.com/nspcc-dev/neo-go/pkg/util"
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"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
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"github.com/nspcc-dev/neo-go/pkg/vm/vmstate"
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)
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// BigInt expects correct execution (HALT state) with a single stack item
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// returned. A big.Int is extracted from this item and returned.
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func BigInt(r *result.Invoke, err error) (*big.Int, error) {
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itm, err := Item(r, err)
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if err != nil {
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return nil, err
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}
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return itm.TryInteger()
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}
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// Bool expects correct execution (HALT state) with a single stack item
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// returned. A bool is extracted from this item and returned.
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func Bool(r *result.Invoke, err error) (bool, error) {
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itm, err := Item(r, err)
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if err != nil {
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return false, err
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}
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return itm.TryBool()
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}
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// Int64 expects correct execution (HALT state) with a single stack item
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// returned. An int64 is extracted from this item and returned.
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func Int64(r *result.Invoke, err error) (int64, error) {
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itm, err := Item(r, err)
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if err != nil {
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return 0, err
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}
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i, err := itm.TryInteger()
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if err != nil {
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return 0, err
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}
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if !i.IsInt64() {
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return 0, errors.New("int64 overflow")
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}
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return i.Int64(), nil
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}
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// LimitedInt64 is similar to Int64 except it allows to set minimum and maximum
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// limits to be checked, so if it doesn't return an error the value is more than
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// min and less than max.
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func LimitedInt64(r *result.Invoke, err error, min int64, max int64) (int64, error) {
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i, err := Int64(r, err)
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if err != nil {
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return 0, err
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}
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if i < min {
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return 0, errors.New("too small value")
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}
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if i > max {
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return 0, errors.New("too big value")
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}
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return i, nil
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}
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// Bytes expects correct execution (HALT state) with a single stack item
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// returned. A slice of bytes is extracted from this item and returned.
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func Bytes(r *result.Invoke, err error) ([]byte, error) {
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itm, err := Item(r, err)
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if err != nil {
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return nil, err
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}
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return itm.TryBytes()
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}
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// UTF8String expects correct execution (HALT state) with a single stack item
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// returned. A string is extracted from this item and checked for UTF-8
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// correctness, valid strings are then returned.
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func UTF8String(r *result.Invoke, err error) (string, error) {
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b, err := Bytes(r, err)
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if err != nil {
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return "", err
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}
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if !utf8.Valid(b) {
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return "", errors.New("not a UTF-8 string")
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}
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return string(b), nil
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}
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// PrintableASCIIString expects correct execution (HALT state) with a single
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// stack item returned. A string is extracted from this item and checked to
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// only contain ASCII characters in printable range, valid strings are then
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// returned.
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func PrintableASCIIString(r *result.Invoke, err error) (string, error) {
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s, err := UTF8String(r, err)
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if err != nil {
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return "", err
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}
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for _, c := range s {
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if c < 32 || c >= 127 {
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return "", errors.New("not a printable ASCII string")
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}
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}
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return s, nil
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}
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// Uint160 expects correct execution (HALT state) with a single stack item
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// returned. An util.Uint160 is extracted from this item and returned.
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func Uint160(r *result.Invoke, err error) (util.Uint160, error) {
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b, err := Bytes(r, err)
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if err != nil {
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return util.Uint160{}, err
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}
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return util.Uint160DecodeBytesBE(b)
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}
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// Uint256 expects correct execution (HALT state) with a single stack item
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// returned. An util.Uint256 is extracted from this item and returned.
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func Uint256(r *result.Invoke, err error) (util.Uint256, error) {
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b, err := Bytes(r, err)
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if err != nil {
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return util.Uint256{}, err
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}
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return util.Uint256DecodeBytesBE(b)
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}
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// SessionIterator expects correct execution (HALT state) with a single stack
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// item returned. If this item is an iterator it's returned to the caller along
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// with the session ID.
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func SessionIterator(r *result.Invoke, err error) (uuid.UUID, result.Iterator, error) {
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itm, err := Item(r, err)
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if err != nil {
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return uuid.UUID{}, result.Iterator{}, err
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}
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if t := itm.Type(); t != stackitem.InteropT {
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return uuid.UUID{}, result.Iterator{}, fmt.Errorf("expected InteropInterface, got %s", t)
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}
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iter, ok := itm.Value().(result.Iterator)
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if !ok {
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return uuid.UUID{}, result.Iterator{}, errors.New("the item is InteropInterface, but not an Iterator")
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}
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if (r.Session == uuid.UUID{}) && iter.ID != nil {
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return uuid.UUID{}, result.Iterator{}, errors.New("server returned iterator ID, but no session ID")
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}
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return r.Session, iter, nil
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}
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// Array expects correct execution (HALT state) with a single array stack item
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// returned. This item is returned to the caller. Notice that this function can
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// be used for structures as well since they're also represented as slices of
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// stack items (the number of them and their types are structure-specific).
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func Array(r *result.Invoke, err error) ([]stackitem.Item, error) {
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itm, err := Item(r, err)
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if err != nil {
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return nil, err
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}
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arr, ok := itm.Value().([]stackitem.Item)
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if !ok {
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return nil, errors.New("not an array")
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}
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return arr, nil
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}
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// ArrayOfBytes checks the result for correct state (HALT) and then extracts a
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// slice of byte slices from the returned stack item.
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func ArrayOfBytes(r *result.Invoke, err error) ([][]byte, error) {
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a, err := Array(r, err)
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if err != nil {
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return nil, err
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}
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res := make([][]byte, len(a))
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for i := range a {
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b, err := a[i].TryBytes()
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if err != nil {
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return nil, fmt.Errorf("element %d is not a byte string: %w", i, err)
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}
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res[i] = b
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}
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return res, nil
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}
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// ArrayOfUint160 checks the result for correct state (HALT) and then extracts a
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// slice of util.Uint160 from the returned stack item.
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func ArrayOfUint160(r *result.Invoke, err error) ([]util.Uint160, error) {
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a, err := Array(r, err)
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if err != nil {
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return nil, err
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}
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res := make([]util.Uint160, len(a))
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for i := range a {
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b, err := a[i].TryBytes()
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if err != nil {
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return nil, fmt.Errorf("element %d is not a byte string: %w", i, err)
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}
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u, err := util.Uint160DecodeBytesBE(b)
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if err != nil {
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return nil, fmt.Errorf("element %d is not a uint160: %w", i, err)
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}
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res[i] = u
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}
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return res, nil
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}
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// ArrayOfPublicKeys checks the result for correct state (HALT) and then
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// extracts a slice of public keys from the returned stack item.
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func ArrayOfPublicKeys(r *result.Invoke, err error) (keys.PublicKeys, error) {
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arr, err := Array(r, err)
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if err != nil {
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return nil, err
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}
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pks := make(keys.PublicKeys, len(arr))
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for i, item := range arr {
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val, err := item.TryBytes()
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if err != nil {
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return nil, fmt.Errorf("invalid array element #%d: %s", i, item.Type())
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}
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pks[i], err = keys.NewPublicKeyFromBytes(val, elliptic.P256())
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if err != nil {
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return nil, fmt.Errorf("array element #%d in not a key: %w", i, err)
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}
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}
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return pks, nil
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}
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// Map expects correct execution (HALT state) with a single stack item
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// returned. A stackitem.Map is extracted from this item and returned.
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func Map(r *result.Invoke, err error) (*stackitem.Map, error) {
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itm, err := Item(r, err)
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if err != nil {
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return nil, err
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}
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if t := itm.Type(); t != stackitem.MapT {
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return nil, fmt.Errorf("%s is not a map", t.String())
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}
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return itm.(*stackitem.Map), nil
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}
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func checkResOK(r *result.Invoke, err error) error {
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if err != nil {
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return err
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}
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if r.State != vmstate.Halt.String() {
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return fmt.Errorf("invocation failed: %s", r.FaultException)
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}
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return nil
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}
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// Item returns a stack item from the result if execution was successful (HALT
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// state) and if it's the only element on the result stack.
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func Item(r *result.Invoke, err error) (stackitem.Item, error) {
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err = checkResOK(r, err)
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if err != nil {
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return nil, err
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}
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if len(r.Stack) == 0 {
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return nil, errors.New("result stack is empty")
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}
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if len(r.Stack) > 1 {
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return nil, fmt.Errorf("too many (%d) result items", len(r.Stack))
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}
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return r.Stack[0], nil
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}
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