resolver

Documentation

Overview

Package resolver implements utilities for resolving paths within ipfs.

Index

• Variables
• func ResolveSingle(ctx context.Context, ds ipld.NodeGetter, nd ipld.Node, names []string) (*ipld.Link, []string, error)
• type ErrNoLink
  • func (e ErrNoLink) Error() string
• type Resolver
  • func NewBasicResolver(ds ipld.DAGService) *Resolver
  • func (r *Resolver) ResolveLinks(ctx context.Context, ndd ipld.Node, names []string) ([]ipld.Node, error)
  • func (r *Resolver) ResolvePath(ctx context.Context, fpath path.Path) (ipld.Node, error)
  • func (r *Resolver) ResolvePathComponents(ctx context.Context, fpath path.Path) ([]ipld.Node, error)
  • func (r *Resolver) ResolveToLastNode(ctx context.Context, fpath path.Path) (ipld.Node, []string, error)

Variables

var ErrNoComponents = errors.New(
	"path must contain at least one component")

ErrNoComponents is used when Paths after a protocol do not contain at least one component

Functions

func ResolveSingle

func ResolveSingle(ctx context.Context, ds ipld.NodeGetter, nd ipld.Node, names []string) (*ipld.Link, []string, error)

ResolveSingle simply resolves one hop of a path through a graph with no extra context (does not opaquely resolve through sharded nodes)

Types

type ErrNoLink

type ErrNoLink struct {
	Name string
	Node *cid.Cid
}

ErrNoLink is returned when a link is not found in a path

func (ErrNoLink) Error

func (e ErrNoLink) Error() string

Error implements the Error interface for ErrNoLink with a useful human readable message.

type Resolver

type Resolver struct {
	DAG ipld.NodeGetter

	ResolveOnce func(ctx context.Context, ds ipld.NodeGetter, nd ipld.Node, names []string) (*ipld.Link, []string, error)
}

Resolver provides path resolution to IPFS It has a pointer to a DAGService, which is uses to resolve nodes. TODO: now that this is more modular, try to unify this code with the

the resolvers in namesys

func NewBasicResolver

func NewBasicResolver(ds ipld.DAGService) *Resolver

NewBasicResolver constructs a new basic resolver.

func (*Resolver) ResolveLinks

func (r *Resolver) ResolveLinks(ctx context.Context, ndd ipld.Node, names []string) ([]ipld.Node, error)

ResolveLinks iteratively resolves names by walking the link hierarchy. Every node is fetched from the DAGService, resolving the next name. Returns the list of nodes forming the path, starting with ndd. This list is guaranteed never to be empty.

ResolveLinks(nd, []string{"foo", "bar", "baz"}) would retrieve "baz" in ("bar" in ("foo" in nd.Links).Links).Links

func (*Resolver) ResolvePath

func (r *Resolver) ResolvePath(ctx context.Context, fpath path.Path) (ipld.Node, error)

ResolvePath fetches the node for given path. It returns the last item returned by ResolvePathComponents.

func (*Resolver) ResolvePathComponents

func (r *Resolver) ResolvePathComponents(ctx context.Context, fpath path.Path) ([]ipld.Node, error)

ResolvePathComponents fetches the nodes for each segment of the given path. It uses the first path component as a hash (key) of the first node, then resolves all other components walking the links, with ResolveLinks.

func (*Resolver) ResolveToLastNode

func (r *Resolver) ResolveToLastNode(ctx context.Context, fpath path.Path) (ipld.Node, []string, error)

ResolveToLastNode walks the given path and returns the ipld.Node referenced by the last element in it.