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Move anchor server to pkg/anchor/server.go.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,96 @@ | ||
| package anchor | ||
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| import ( | ||
| "context" | ||
| "errors" | ||
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| api "github.com/wetware/ww/api/anchor" | ||
| ) | ||
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| type server struct{ *Node } | ||
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| func (s server) Shutdown() { | ||
| s.Release() // nodeHook holds the lock when shutting down. | ||
| } | ||
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| func (s server) Ls(ctx context.Context, call api.Anchor_ls) error { | ||
| s.Lock() | ||
| defer s.Unlock() | ||
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| children := s.children | ||
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| if len(children) == 0 { | ||
| return nil | ||
| } | ||
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| res, err := call.AllocResults() | ||
| if err != nil { | ||
| return err | ||
| } | ||
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| cs, err := res.NewChildren(int32(len(children))) | ||
| if err != nil { | ||
| return err | ||
| } | ||
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| var index int | ||
| for name, child := range children { | ||
| if err = cs.At(index).SetName(name); err != nil { | ||
| break | ||
| } | ||
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| if err = cs.At(index).SetAnchor(anchor(child)); err != nil { | ||
| break | ||
| } | ||
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| index++ | ||
| } | ||
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| return err | ||
| } | ||
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| // FIXME: there is currently a vector for resource-exhaustion attacks. | ||
| // We don't enforce a maximum depth on anchors, nor do we enforce a max | ||
| // number of children per node. An attacker can exploit this by walking | ||
| // an arbitrarily long path and/or by creating arbitrarily many anchors, | ||
| // ultimately exhausting the attacker's memory. | ||
| func (s server) Walk(ctx context.Context, call api.Anchor_walk) error { | ||
| path := newPath(call) | ||
| if path.Err() != nil { | ||
| return path.Err() | ||
| } | ||
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| res, err := call.AllocResults() | ||
| if err != nil { | ||
| return err | ||
| } | ||
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| // Iteratively "walk" to designated path. It's important to avoid | ||
| // recursion, so that RPCs can't blow up the stack. | ||
| // | ||
| // Each iteration of the loop shadows the n symbol, including its | ||
| // embedded node, such that we are holding the final node when we | ||
| // exit the loop. | ||
| for path, name := path.Next(); name != ""; path, name = path.Next() { | ||
| s.Node = s.Child(name) // shallow copy | ||
| } | ||
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| return res.SetAnchor(anchor(s)) | ||
| } | ||
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| func (s server) Cell(ctx context.Context, call api.Anchor_cell) error { | ||
| return errors.New("NOT IMPLEMENTED") // TODO(soon): implement Anchor.Cell() | ||
| } | ||
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| func anchor(n interface{ Anchor() Anchor }) api.Anchor { | ||
| return api.Anchor(n.Anchor()) | ||
| } | ||
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| func newPath(call api.Anchor_walk) Path { | ||
| path, err := call.Args().Path() | ||
| if err != nil { | ||
| return failure(err) | ||
| } | ||
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| return NewPath(path) | ||
| } |