limits: new package with storage limits

Packages like core/state or core/mpt shouldn't import whole core/storage just
to get some constant value, it's not a good dependency.

pkg/config/limits/limits.go

@@ -0,0 +1,17 @@
+/*
+Package limits contains a number of system-wide hardcoded constants.
+Many of the Neo protocol parameters can be adjusted by the configuration, but
+some can not and this package contains hardcoded limits that are relevant for
+many applications.
+*/
+package limits
+
+const (
+	// MaxStorageKeyLen is the maximum length of a key for storage items.
+	// Contracts can't use keys longer than that in their requests to the DB.
+	MaxStorageKeyLen = 64
+	// MaxStorageValueLen is the maximum length of a value for storage items.
+	// It is set to be the maximum value for uint16, contracts can't put
+	// values longer than that into the DB.
+	MaxStorageValueLen = 65535
+)

pkg/core/blockchain.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/nspcc-dev/neo-go/pkg/config"
+	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer"
 	"github.com/nspcc-dev/neo-go/pkg/core/blockchainer/services"
@@ -1328,7 +1329,7 @@ func (bc *Blockchain) handleNotification(note *state.NotificationEvent, d *dao.S
 	var id []byte
 	if len(arr) == 4 {
 		id, err = arr[3].TryBytes()
-		if err != nil || len(id) > storage.MaxStorageKeyLen {
+		if err != nil || len(id) > limits.MaxStorageKeyLen {
 			return
 		}
 	}

pkg/core/dao/dao.go

@@ -10,6 +10,7 @@ import (
 	"math/big"
 	"sync"
 
+	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
@@ -830,7 +831,7 @@ func (dao *Simple) StoreAsTransaction(tx *transaction.Transaction, index uint32,
 func (dao *Simple) getKeyBuf(len int) []byte {
 	if dao.private {
 		if dao.keyBuf == nil {
-			dao.keyBuf = make([]byte, 0, 1+4+storage.MaxStorageKeyLen) // Prefix, uint32, key.
+			dao.keyBuf = make([]byte, 0, 1+4+limits.MaxStorageKeyLen) // Prefix, uint32, key.
 		}
 		return dao.keyBuf[:len] // Should have enough capacity.
 	}

pkg/core/interop/storage/basic.go

@@ -4,8 +4,8 @@ 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/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 )
 
@@ -81,10 +81,10 @@ func getContextInternal(ic *interop.Context, isReadOnly bool) error {
 }
 
 func putWithContext(ic *interop.Context, stc *Context, key []byte, value []byte) error {
-	if len(key) > storage.MaxStorageKeyLen {
+	if len(key) > limits.MaxStorageKeyLen {
 		return errors.New("key is too big")
 	}
-	if len(value) > storage.MaxStorageValueLen {
+	if len(value) > limits.MaxStorageValueLen {
 		return errors.New("value is too big")
 	}
 	if stc.ReadOnly {

pkg/core/interop/storage/storage_test.go

@@ -5,6 +5,7 @@ import (
 	"math/big"
 	"testing"
 
+	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop"
@@ -12,7 +13,6 @@ import (
 	istorage "github.com/nspcc-dev/neo-go/pkg/core/interop/storage"
 	"github.com/nspcc-dev/neo-go/pkg/core/native"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
-	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/neotest/chain"
@@ -61,7 +61,7 @@ func TestPut(t *testing.T) {
 	})
 
 	t.Run("check limits", func(t *testing.T) {
-		initVM(t, make([]byte, storage.MaxStorageKeyLen), make([]byte, storage.MaxStorageValueLen), -1)
+		initVM(t, make([]byte, limits.MaxStorageKeyLen), make([]byte, limits.MaxStorageValueLen), -1)
 		require.NoError(t, istorage.Put(ic))
 	})
 
@@ -72,11 +72,11 @@ func TestPut(t *testing.T) {
 			require.Error(t, istorage.Put(ic))
 		})
 		t.Run("big key", func(t *testing.T) {
-			initVM(t, make([]byte, storage.MaxStorageKeyLen+1), []byte{1}, -1)
+			initVM(t, make([]byte, limits.MaxStorageKeyLen+1), []byte{1}, -1)
 			require.Error(t, istorage.Put(ic))
 		})
 		t.Run("big value", func(t *testing.T) {
-			initVM(t, []byte{1}, make([]byte, storage.MaxStorageValueLen+1), -1)
+			initVM(t, []byte{1}, make([]byte, limits.MaxStorageValueLen+1), -1)
 			require.Error(t, istorage.Put(ic))
 		})
 	})

pkg/core/mpt/extension.go

@@ -6,14 +6,14 @@ import (
 	"errors"
 	"fmt"
 
-	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
 const (
 	// maxPathLength is the max length of the extension node key.
-	maxPathLength = (storage.MaxStorageKeyLen + 4) * 2
+	maxPathLength = (limits.MaxStorageKeyLen + 4) * 2
 
 	// MaxKeyLength is the max length of the key to put in the trie
 	// before transforming to nibbles.

pkg/core/mpt/leaf.go

@@ -5,13 +5,13 @@ import (
 	"errors"
 	"fmt"
 
-	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
 
 // MaxValueLength is the max length of a leaf node value.
-const MaxValueLength = 3 + storage.MaxStorageValueLen + 1
+const MaxValueLength = 3 + limits.MaxStorageValueLen + 1
 
 // LeafNode represents an MPT's leaf node.
 type LeafNode struct {

pkg/core/state/tokens.go

@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"math/big"
 
-	"github.com/nspcc-dev/neo-go/pkg/core/storage"
+	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
 	"github.com/nspcc-dev/neo-go/pkg/io"
 	"github.com/nspcc-dev/neo-go/pkg/util"
@@ -224,5 +224,5 @@ func (t *NEP11Transfer) EncodeBinary(w *io.BinWriter) {
 // DecodeBinary implements the io.Serializable interface.
 func (t *NEP11Transfer) DecodeBinary(r *io.BinReader) {
 	t.NEP17Transfer.DecodeBinary(r)
-	t.ID = r.ReadVarBytes(storage.MaxStorageKeyLen)
+	t.ID = r.ReadVarBytes(limits.MaxStorageKeyLen)
 }

pkg/core/storage/store.go

@@ -41,14 +41,6 @@ const (
 	ExecTransaction byte = 2
 )
 
-const (
-	// MaxStorageKeyLen is the maximum length of a key for storage items.
-	MaxStorageKeyLen = 64
-	// MaxStorageValueLen is the maximum length of a value for storage items.
-	// It is set to be the maximum value for uint16.
-	MaxStorageValueLen = 65535
-)
-
 // Operation represents a single KV operation (add/del/change) performed
 // in the DB.
 type Operation struct {

pkg/rpc/server/server.go

@@ -20,6 +20,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/gorilla/websocket"
+	"github.com/nspcc-dev/neo-go/pkg/config/limits"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
 	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
@@ -31,7 +32,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
 	"github.com/nspcc-dev/neo-go/pkg/core/native"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
-	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
@@ -846,7 +846,7 @@ contract_loop:
 		curAsset := &bs.Balances[len(bs.Balances)-1]
 		for i := range toks {
 			id, err := toks[i].TryBytes()
-			if err != nil || len(id) > storage.MaxStorageKeyLen {
+			if err != nil || len(id) > limits.MaxStorageKeyLen {
 				continue
 			}
 			var amount = "1"