From e41ac96207abfee7eaf3fdb813834cf028d12275 Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Fri, 19 Oct 2018 17:08:22 +0100
Subject: [PATCH] switch to new raceless routing event interface

fixes #5616

License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>
---
 core/commands/dht.go | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/core/commands/dht.go b/core/commands/dht.go
index 617476596..8d7855a24 100644
--- a/core/commands/dht.go
+++ b/core/commands/dht.go
@@ -72,23 +72,24 @@ var queryDhtCmd = &cmds.Command{
 			return
 		}
 
-		events := make(chan *notif.QueryEvent)
-		ctx := notif.RegisterForQueryEvents(req.Context(), events)
-
 		id, err := peer.IDB58Decode(req.Arguments()[0])
 		if err != nil {
 			res.SetError(cmds.ClientError("invalid peer ID"), cmdkit.ErrClient)
 			return
 		}
 
+		ctx, cancel := context.WithCancel(req.Context())
+		ctx, events := notif.RegisterForQueryEvents(ctx)
+
 		closestPeers, err := n.DHT.GetClosestPeers(ctx, string(id))
 		if err != nil {
+			cancel()
 			res.SetError(err, cmdkit.ErrNormal)
 			return
 		}
 
 		go func() {
-			defer close(events)
+			defer cancel()
 			for p := range closestPeers {
 				notif.PublishQueryEvent(ctx, &notif.QueryEvent{
 					ID:   p,
@@ -182,8 +183,6 @@ var findProvidersDhtCmd = &cmds.Command{
 			return
 		}
 
-		events := make(chan *notif.QueryEvent)
-		ctx := notif.RegisterForQueryEvents(req.Context(), events)
 		c, err := cid.Parse(req.Arguments()[0])
 
 		if err != nil {
@@ -194,6 +193,9 @@ var findProvidersDhtCmd = &cmds.Command{
 		outChan := make(chan interface{})
 		res.SetOutput((<-chan interface{})(outChan))
 
+		ctx, cancel := context.WithCancel(req.Context())
+		ctx, events := notif.RegisterForQueryEvents(ctx)
+
 		pchan := n.Routing.FindProvidersAsync(ctx, c, numProviders)
 		go func() {
 			defer close(outChan)
@@ -207,7 +209,7 @@ var findProvidersDhtCmd = &cmds.Command{
 		}()
 
 		go func() {
-			defer close(events)
+			defer cancel()
 			for p := range pchan {
 				np := p
 				notif.PublishQueryEvent(ctx, &notif.QueryEvent{
@@ -320,8 +322,8 @@ var provideRefDhtCmd = &cmds.Command{
 		outChan := make(chan interface{})
 		res.SetOutput((<-chan interface{})(outChan))
 
-		events := make(chan *notif.QueryEvent)
-		ctx := notif.RegisterForQueryEvents(req.Context(), events)
+		ctx, cancel := context.WithCancel(req.Context())
+		ctx, events := notif.RegisterForQueryEvents(ctx)
 
 		go func() {
 			defer close(outChan)
@@ -335,7 +337,7 @@ var provideRefDhtCmd = &cmds.Command{
 		}()
 
 		go func() {
-			defer close(events)
+			defer cancel()
 			var err error
 			if rec {
 				err = provideKeysRec(ctx, n.Routing, n.DAG, cids)
@@ -449,8 +451,8 @@ var findPeerDhtCmd = &cmds.Command{
 		outChan := make(chan interface{})
 		res.SetOutput((<-chan interface{})(outChan))
 
-		events := make(chan *notif.QueryEvent)
-		ctx := notif.RegisterForQueryEvents(req.Context(), events)
+		ctx, cancel := context.WithCancel(req.Context())
+		ctx, events := notif.RegisterForQueryEvents(ctx)
 
 		go func() {
 			defer close(outChan)
@@ -464,7 +466,7 @@ var findPeerDhtCmd = &cmds.Command{
 		}()
 
 		go func() {
-			defer close(events)
+			defer cancel()
 			pi, err := n.Routing.FindPeer(ctx, pid)
 			if err != nil {
 				notif.PublishQueryEvent(ctx, &notif.QueryEvent{
@@ -554,8 +556,8 @@ Different key types can specify other 'best' rules.
 		outChan := make(chan interface{})
 		res.SetOutput((<-chan interface{})(outChan))
 
-		events := make(chan *notif.QueryEvent)
-		ctx := notif.RegisterForQueryEvents(req.Context(), events)
+		ctx, cancel := context.WithCancel(req.Context())
+		ctx, events := notif.RegisterForQueryEvents(ctx)
 
 		go func() {
 			defer close(outChan)
@@ -568,7 +570,7 @@ Different key types can specify other 'best' rules.
 		}()
 
 		go func() {
-			defer close(events)
+			defer cancel()
 			val, err := n.Routing.GetValue(ctx, dhtkey)
 			if err != nil {
 				notif.PublishQueryEvent(ctx, &notif.QueryEvent{
@@ -659,9 +661,6 @@ NOTE: A value may not exceed 2048 bytes.
 			return
 		}
 
-		events := make(chan *notif.QueryEvent)
-		ctx := notif.RegisterForQueryEvents(req.Context(), events)
-
 		key, err := escapeDhtKey(req.Arguments()[0])
 		if err != nil {
 			res.SetError(err, cmdkit.ErrNormal)
@@ -673,6 +672,9 @@ NOTE: A value may not exceed 2048 bytes.
 
 		data := req.Arguments()[1]
 
+		ctx, cancel := context.WithCancel(req.Context())
+		ctx, events := notif.RegisterForQueryEvents(ctx)
+
 		go func() {
 			defer close(outChan)
 			for e := range events {
@@ -685,7 +687,7 @@ NOTE: A value may not exceed 2048 bytes.
 		}()
 
 		go func() {
-			defer close(events)
+			defer cancel()
 			err := n.Routing.PutValue(ctx, key, []byte(data))
 			if err != nil {
 				notif.PublishQueryEvent(ctx, &notif.QueryEvent{