103 lines
2.0 KiB
Go
103 lines
2.0 KiB
Go
package cid
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import (
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"context"
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)
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// Set is a implementation of a set of Cids, that is, a structure
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// to which holds a single copy of every Cids that is added to it.
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type Set struct {
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set map[string]struct{}
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}
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// NewSet initializes and returns a new Set.
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func NewSet() *Set {
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return &Set{set: make(map[string]struct{})}
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}
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// Add puts a Cid in the Set.
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func (s *Set) Add(c *Cid) {
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s.set[string(c.Bytes())] = struct{}{}
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}
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// Has returns if the Set contains a given Cid.
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func (s *Set) Has(c *Cid) bool {
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_, ok := s.set[string(c.Bytes())]
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return ok
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}
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// Remove deletes a Cid from the Set.
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func (s *Set) Remove(c *Cid) {
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delete(s.set, string(c.Bytes()))
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}
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// Len returns how many elements the Set has.
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func (s *Set) Len() int {
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return len(s.set)
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}
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// Keys returns the Cids in the set.
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func (s *Set) Keys() []*Cid {
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out := make([]*Cid, 0, len(s.set))
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for k := range s.set {
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c, _ := Cast([]byte(k))
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out = append(out, c)
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}
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return out
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}
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// Visit adds a Cid to the set only if it is
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// not in it already.
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func (s *Set) Visit(c *Cid) bool {
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if !s.Has(c) {
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s.Add(c)
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return true
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}
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return false
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}
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// ForEach allows to run a custom function on each
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// Cid in the set.
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func (s *Set) ForEach(f func(c *Cid) error) error {
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for cs := range s.set {
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c, _ := Cast([]byte(cs))
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err := f(c)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// StreamingSet is an extension of Set which allows to implement back-pressure
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// for the Visit function
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type StreamingSet struct {
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Set *Set
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New chan *Cid
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}
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// NewStreamingSet initializes and returns new Set.
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func NewStreamingSet() *StreamingSet {
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return &StreamingSet{
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Set: NewSet(),
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New: make(chan *Cid),
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}
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}
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// Visitor creates new visitor which adds a Cids to the set and emits them to
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// the set.New channel
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func (s *StreamingSet) Visitor(ctx context.Context) func(c *Cid) bool {
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return func(c *Cid) bool {
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if s.Set.Visit(c) {
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select {
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case s.New <- c:
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case <-ctx.Done():
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}
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return true
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}
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return false
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}
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}
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