export range and small refactor

api/api_full.go

@@ -163,6 +163,8 @@ type FullNode interface {
 	// If oldmsgskip is set, messages from before the requested roots are also not included.
 	ChainExport(ctx context.Context, nroots abi.ChainEpoch, oldmsgskip bool, tsk types.TipSetKey) (<-chan []byte, error) //perm:read
 
+	ChainExportRange(ctx context.Context, oldmsgskip bool, from, to types.TipSetKey) (<-chan []byte, error) //perm:read
+
 	// ChainCheckBlockstore performs an (asynchronous) health check on the chain/state blockstore
 	// if supported by the underlying implementation.
 	ChainCheckBlockstore(context.Context) error //perm:admin

chain/store/snapshot.go

@@ -23,6 +23,20 @@ func (cs *ChainStore) UnionStore() bstore.Blockstore {
 }
 
 func (cs *ChainStore) Export(ctx context.Context, ts *types.TipSet, inclRecentRoots abi.ChainEpoch, skipOldMsgs bool, w io.Writer) error {
+	pleaseVisit := func(b types.BlockHeader) bool {
+		return b.Height > ts.Height()-inclRecentRoots
+	}
+	return cs.exportIf(ctx, ts, pleaseVisit, skipOldMsgs, w)
+}
+
+func (cs *ChainStore) ExportRange(ctx context.Context, from, to *types.TipSet, skipOldMsgs bool, w io.Writer) error {
+	pleaseVisit := func(b types.BlockHeader) bool {
+		return b.Height >= from.Height() && b.Height < to.Height()
+	}
+	return cs.exportIf(ctx, to, pleaseVisit, skipOldMsgs, w)
+}
+
+func (cs *ChainStore) exportIf(ctx context.Context, ts *types.TipSet, visit func(b types.BlockHeader) bool, skipOldMsgs bool, w io.Writer) error {
 	h := &car.CarHeader{
 		Roots:   ts.Cids(),
 		Version: 1,
@@ -33,7 +47,7 @@ func (cs *ChainStore) Export(ctx context.Context, ts *types.TipSet, inclRecentRo
 	}
 
 	unionBs := cs.UnionStore()
-	return cs.WalkSnapshot(ctx, ts, inclRecentRoots, skipOldMsgs, true, func(c cid.Cid) error {
+	return cs.WalkSnapshot(ctx, ts, visit, skipOldMsgs, true, func(c cid.Cid) error {
 		blk, err := unionBs.Get(ctx, c)
 		if err != nil {
 			return xerrors.Errorf("writing object to car, bs.Get: %w", err)
@@ -66,7 +80,7 @@ func (cs *ChainStore) Import(ctx context.Context, r io.Reader) (*types.TipSet, e
 	return root, nil
 }
 
-func (cs *ChainStore) WalkSnapshot(ctx context.Context, ts *types.TipSet, inclRecentRoots abi.ChainEpoch, skipOldMsgs, skipMsgReceipts bool, cb func(cid.Cid) error) error {
+func (cs *ChainStore) WalkSnapshot(ctx context.Context, ts *types.TipSet, visit func(b types.BlockHeader) bool, skipOldMsgs bool, skipMsgReceipts bool, cb func(cid.Cid) error) error {
 	if ts == nil {
 		ts = cs.GetHeaviestTipSet()
 	}
@@ -104,7 +118,7 @@ func (cs *ChainStore) WalkSnapshot(ctx context.Context, ts *types.TipSet, inclRe
 		}
 
 		var cids []cid.Cid
-		if !skipOldMsgs || b.Height > ts.Height()-inclRecentRoots {
+		if !skipOldMsgs || visit(b) {
 			if walked.Visit(b.Messages) {
 				mcids, err := recurseLinks(ctx, cs.chainBlockstore, walked, b.Messages, []cid.Cid{b.Messages})
 				if err != nil {
@@ -125,7 +139,7 @@ func (cs *ChainStore) WalkSnapshot(ctx context.Context, ts *types.TipSet, inclRe
 
 		out := cids
 
-		if b.Height == 0 || b.Height > ts.Height()-inclRecentRoots {
+		if b.Height == 0 || visit(b) {
 			if walked.Visit(b.ParentStateRoot) {
 				cids, err := recurseLinks(ctx, cs.stateBlockstore, walked, b.ParentStateRoot, []cid.Cid{b.ParentStateRoot})
 				if err != nil {

node/impl/full/chain.go

@@ -584,17 +584,39 @@ func (m *ChainModule) ChainGetMessage(ctx context.Context, mc cid.Cid) (*types.M
 	return cm.VMMessage(), nil
 }
 
+func (a *ChainAPI) ChainExportRange(ctx context.Context, skipoldmsgs bool, from, to types.TipSetKey) (<-chan []byte, error) {
+	export := func(w io.Writer) error {
+		from, err := a.Chain.GetTipSetFromKey(ctx, from)
+		if err != nil {
+			return xerrors.Errorf("loading from tipset %s: %w", from, err)
+		}
+		to, err := a.Chain.GetTipSetFromKey(ctx, to)
+		if err != nil {
+			return xerrors.Errorf("loading tipset %s: %w", to, err)
+		}
+		return a.Chain.ExportRange(ctx, from, to, skipoldmsgs, w)
+	}
+	return a.chainExport(ctx, export)
+}
+
 func (a *ChainAPI) ChainExport(ctx context.Context, nroots abi.ChainEpoch, skipoldmsgs bool, tsk types.TipSetKey) (<-chan []byte, error) {
-	ts, err := a.Chain.GetTipSetFromKey(ctx, tsk)
-	if err != nil {
-		return nil, xerrors.Errorf("loading tipset %s: %w", tsk, err)
+	export := func(w io.Writer) error {
+		ts, err := a.Chain.GetTipSetFromKey(ctx, tsk)
+		if err != nil {
+			return xerrors.Errorf("loading tipset %s: %w", tsk, err)
+		}
+		return a.Chain.Export(ctx, ts, nroots, skipoldmsgs, w)
 	}
+	return a.chainExport(ctx, export)
+}
+
+func (a *ChainAPI) chainExport(ctx context.Context, export func(w io.Writer) error) (<-chan []byte, error) {
+
 	r, w := io.Pipe()
 	out := make(chan []byte)
 	go func() {
 		bw := bufio.NewWriterSize(w, 1<<20)
-
-		err := a.Chain.Export(ctx, ts, nroots, skipoldmsgs, bw)
+		err := export(bw)
 		bw.Flush()            //nolint:errcheck // it is a write to a pipe
 		w.CloseWithError(err) //nolint:errcheck // it is a pipe
 	}()