/
walker.go
73 lines (60 loc) · 1.7 KB
/
walker.go
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// Copyright 2019 Netflix, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package dag
import (
"context"
"github.com/Netflix/p2plab/pkg/traceutil"
cid "github.com/ipfs/go-cid"
ipld "github.com/ipfs/go-ipld-format"
opentracing "github.com/opentracing/opentracing-go"
"golang.org/x/sync/errgroup"
)
func Walk(ctx context.Context, c cid.Cid, ng ipld.NodeGetter) error {
span, ctx := traceutil.StartSpanFromContext(ctx, "dag.Walk")
defer span.Finish()
span.SetTag("cid", c.String())
nd, err := ng.Get(ctx, c)
if err != nil {
return err
}
return walk(ctx, nd, ng)
}
func walk(ctx context.Context, nd ipld.Node, ng ipld.NodeGetter) error {
var cids []cid.Cid
for _, link := range nd.Links() {
cids = append(cids, link.Cid)
}
if len(cids) > 0 {
var span opentracing.Span
span, ctx = traceutil.StartSpanFromContext(ctx, "dag.walk")
defer span.Finish()
span.SetTag("cid", nd.Cid().String())
}
eg, gctx := errgroup.WithContext(ctx)
ndChan := ng.GetMany(ctx, cids)
for ndOpt := range ndChan {
if ndOpt.Err != nil {
return ndOpt.Err
}
nd := ndOpt.Node
eg.Go(func() error {
return walk(gctx, nd, ng)
})
}
err := eg.Wait()
if err != nil {
return err
}
return nil
}