Create wrapper for syncable VM (#5480)

Author: alarso16

vms/saevm/adaptor/BUILD.bazel

@@ -2,7 +2,10 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_library(
     name = "adaptor",
-    srcs = ["adaptor.go"],
+    srcs = [
+        "sync.go",
+        "vm.go",
+    ],
     importpath = "github.com/ava-labs/avalanchego/vms/saevm/adaptor",
     visibility = ["//visibility:public"],
     deps = [

vms/saevm/adaptor/sync.go

@@ -0,0 +1,91 @@
+// Copyright (C) 2019, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package adaptor
+
+import (
+	"context"
+
+	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/snow/engine/snowman/block"
+)
+
+// SyncableVM adapts a [block.StateSyncableVM] and [block.StateSummary] for
+// // stateless use of the summary. See the respective interfaces for more details.
+type SyncableVM[SP SummaryProperties] interface {
+	StateSyncEnabled(context.Context) (bool, error)
+	GetLastStateSummary(context.Context) (SP, error)
+	GetOngoingSyncStateSummary(context.Context) (SP, error)
+	GetStateSummary(context.Context, uint64) (SP, error)
+	ParseStateSummary(context.Context, []byte) (SP, error)
+	AcceptSummary(context.Context, SP) (block.StateSyncMode, error)
+}
+
+// SummaryProperties is a read-only subset of [block.StateSummary].
+// [block.StateSummary.Accept] is not included, as it is handled by [SyncableVM].
+type SummaryProperties interface {
+	ID() ids.ID
+	Bytes() []byte
+	Height() uint64
+}
+
+// ConvertStateSync transforms a [SyncableVM] into a [block.StateSyncableVM].
+func ConvertStateSync[SP SummaryProperties](vm SyncableVM[SP]) block.StateSyncableVM {
+	return syncAdaptor[SP]{
+		SyncableVM: vm,
+	}
+}
+
+type syncAdaptor[SP SummaryProperties] struct {
+	SyncableVM[SP]
+}
+
+// Summary is an implementation of [block.StateSummary], used by chains returned
+// by [ConvertStateSync]. The [SummaryProperties] can be accessed with
+// [Summary.Unwrap].
+type Summary[SP SummaryProperties] struct {
+	s  SP
+	vm SyncableVM[SP]
+}
+
+// Unwrap returns the underlying [SummaryProperties] of the [Summary].
+func (s Summary[SP]) Unwrap() SP {
+	return s.s
+}
+
+func (vm syncAdaptor[SP]) newSummary(s SP, err error) (block.StateSummary, error) {
+	if err != nil {
+		return nil, err
+	}
+	return Summary[SP]{s, vm.SyncableVM}, nil
+}
+
+func (vm syncAdaptor[SP]) GetLastStateSummary(ctx context.Context) (block.StateSummary, error) {
+	return vm.newSummary(vm.SyncableVM.GetLastStateSummary(ctx))
+}
+
+func (vm syncAdaptor[SP]) GetOngoingSyncStateSummary(ctx context.Context) (block.StateSummary, error) {
+	return vm.newSummary(vm.SyncableVM.GetOngoingSyncStateSummary(ctx))
+}
+
+func (vm syncAdaptor[SP]) GetStateSummary(ctx context.Context, summaryHeight uint64) (block.StateSummary, error) {
+	return vm.newSummary(vm.SyncableVM.GetStateSummary(ctx, summaryHeight))
+}
+
+func (vm syncAdaptor[SP]) ParseStateSummary(ctx context.Context, summaryBytes []byte) (block.StateSummary, error) {
+	return vm.newSummary(vm.SyncableVM.ParseStateSummary(ctx, summaryBytes))
+}
+
+// ID propagates the respective method from the [SummaryProperties] carried by s.
+func (s Summary[SP]) ID() ids.ID { return s.s.ID() }
+
+// Bytes propagates the respective method from the [SummaryProperties] carried by s.
+func (s Summary[SP]) Bytes() []byte { return s.s.Bytes() }
+
+// Height propagates the respective method from the [SummaryProperties] carried by s.
+func (s Summary[SP]) Height() uint64 { return s.s.Height() }
+
+// Accept calls AcceptSummary(s) on the [SyncableVM] that created s.
+func (s Summary[SP]) Accept(ctx context.Context) (block.StateSyncMode, error) {
+	return s.vm.AcceptSummary(ctx, s.s)
+}