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113 lines
3.3 KiB
113 lines
3.3 KiB
package pubsub
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import "github.com/tendermint/tendermint/abci/types"
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// An item to be published to subscribers.
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type item struct {
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Data interface{}
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Events []types.Event
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}
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// A subInfo value records a single subscription.
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type subInfo struct {
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clientID string // chosen by the client
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query Query // chosen by the client
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subID string // assigned at registration
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sub *Subscription // receives published events
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}
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// A subInfoSet is an unordered set of subscription info records.
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type subInfoSet map[*subInfo]struct{}
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func (s subInfoSet) contains(si *subInfo) bool { _, ok := s[si]; return ok }
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func (s subInfoSet) add(si *subInfo) { s[si] = struct{}{} }
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func (s subInfoSet) remove(si *subInfo) { delete(s, si) }
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// withQuery returns the subset of s whose query string matches qs.
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func (s subInfoSet) withQuery(qs string) subInfoSet {
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out := make(subInfoSet)
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for si := range s {
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if si.query.String() == qs {
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out.add(si)
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}
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}
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return out
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}
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// A subIndex is an indexed collection of subscription info records.
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// The index is not safe for concurrent use without external synchronization.
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type subIndex struct {
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all subInfoSet // all subscriptions
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byClient map[string]subInfoSet // per-client subscriptions
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byQuery map[string]subInfoSet // per-query subscriptions
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// TODO(creachadair): We allow indexing by query to support existing use by
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// the RPC service methods for event streaming. Fix up those methods not to
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// require this, and then remove indexing by query.
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}
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// newSubIndex constructs a new, empty subscription index.
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func newSubIndex() *subIndex {
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return &subIndex{
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all: make(subInfoSet),
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byClient: make(map[string]subInfoSet),
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byQuery: make(map[string]subInfoSet),
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}
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}
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// findClients returns the set of subscriptions for the given client ID, or nil.
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func (idx *subIndex) findClientID(id string) subInfoSet { return idx.byClient[id] }
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// findQuery returns the set of subscriptions on the given query string, or nil.
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func (idx *subIndex) findQuery(qs string) subInfoSet { return idx.byQuery[qs] }
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// contains reports whether idx contains any subscription matching the given
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// client ID and query pair.
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func (idx *subIndex) contains(clientID, query string) bool {
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csubs, qsubs := idx.byClient[clientID], idx.byQuery[query]
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if len(csubs) == 0 || len(qsubs) == 0 {
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return false
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}
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for si := range csubs {
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if qsubs.contains(si) {
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return true
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}
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}
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return false
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}
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// add adds si to the index, replacing any previous entry with the same terms.
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// It is the caller's responsibility to check for duplicates before adding.
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// See also the contains method.
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func (idx *subIndex) add(si *subInfo) {
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idx.all.add(si)
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if m := idx.byClient[si.clientID]; m == nil {
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idx.byClient[si.clientID] = subInfoSet{si: struct{}{}}
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} else {
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m.add(si)
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}
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qs := si.query.String()
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if m := idx.byQuery[qs]; m == nil {
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idx.byQuery[qs] = subInfoSet{si: struct{}{}}
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} else {
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m.add(si)
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}
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}
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// removeAll removes all the elements of s from the index.
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func (idx *subIndex) removeAll(s subInfoSet) {
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for si := range s {
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idx.all.remove(si)
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idx.byClient[si.clientID].remove(si)
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if len(idx.byClient[si.clientID]) == 0 {
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delete(idx.byClient, si.clientID)
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}
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if si.query != nil {
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qs := si.query.String()
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idx.byQuery[qs].remove(si)
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if len(idx.byQuery[qs]) == 0 {
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delete(idx.byQuery, qs)
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}
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}
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}
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}
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