From 04bd87475a866c2e8aeea58f8ed9a3647a85e9a5 Mon Sep 17 00:00:00 2001
From: Andy Williams <andy@andywilliams.me>
Date: Sun, 21 Feb 2021 17:29:50 +0000
Subject: [PATCH 1/2] move to an infinite queue for binding callbacks

Fixes #1838
---
 data/binding/queue.go      | 42 ++++++++++++++++++++++++++++++++++----
 data/binding/queue_test.go | 23 +++++++++++++++++++++
 2 files changed, 61 insertions(+), 4 deletions(-)

diff --git a/data/binding/queue.go b/data/binding/queue.go
index 7587a88906..0e353ec3a9 100644
--- a/data/binding/queue.go
+++ b/data/binding/queue.go
@@ -1,6 +1,6 @@
 package binding
 
-var itemQueue = make(chan itemData, 1024)
+var itemQueueIn, itemQueueOut = makeInfiniteQueue()
 
 type itemData struct {
 	fn   func()
@@ -8,16 +8,50 @@ type itemData struct {
 }
 
 func queueItem(f func()) {
-	itemQueue <- itemData{fn: f}
+	itemQueueIn <- &itemData{fn: f}
 }
 
 func init() {
 	go processItems()
 }
 
+func makeInfiniteQueue() (chan<- *itemData, <-chan *itemData) {
+	in := make(chan *itemData)
+	out := make(chan *itemData)
+	go func() {
+		var queued []*itemData
+		pending := func() chan *itemData {
+			if len(queued) == 0 {
+				return nil
+			}
+			return out
+		}
+		next := func() *itemData {
+			if len(queued) == 0 {
+				return nil
+			}
+			return queued[0]
+		}
+		for len(queued) > 0 || in != nil {
+			select {
+			case val, ok := <-in:
+				if !ok {
+					in = nil
+				} else {
+					queued = append(queued, val)
+				}
+			case pending() <- next():
+				queued = queued[1:]
+			}
+		}
+		close(out)
+	}()
+	return in, out
+}
+
 func processItems() {
 	for {
-		i := <-itemQueue
+		i := <-itemQueueOut
 		if i.fn != nil {
 			i.fn()
 		}
@@ -29,6 +63,6 @@ func processItems() {
 
 func waitForItems() {
 	done := make(chan interface{})
-	itemQueue <- itemData{done: done}
+	itemQueueIn <- &itemData{done: done}
 	<-done
 }
diff --git a/data/binding/queue_test.go b/data/binding/queue_test.go
index 41e213cce3..71e71dc38e 100644
--- a/data/binding/queue_test.go
+++ b/data/binding/queue_test.go
@@ -1,6 +1,7 @@
 package binding
 
 import (
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -18,3 +19,25 @@ func TestQueueItem(t *testing.T) {
 	waitForItems()
 	assert.Equal(t, 2, called)
 }
+
+func TestMakeInfiniteQueue(t *testing.T) {
+	var wg sync.WaitGroup
+	in, out := makeInfiniteQueue()
+
+	wg.Add(1)
+	c := 0
+	go func() {
+		for range out {
+			c++
+		}
+		wg.Done()
+	}()
+
+	for i := 0; i < 2048; i++ {
+		in <- &itemData{}
+	}
+	close(in)
+
+	wg.Wait()
+	assert.Equal(t, 2048, c)
+}

From 69431e1eab14a2ee9bf54f45a1f8ddbf8e32d637 Mon Sep 17 00:00:00 2001
From: Andy Williams <andy@andywilliams.me>
Date: Fri, 26 Feb 2021 18:08:10 +0000
Subject: [PATCH 2/2] Initialise queue to a certain capacity

This should make small apps just as performant as before the change
---
 data/binding/queue.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/data/binding/queue.go b/data/binding/queue.go
index 0e353ec3a9..cafaed58d2 100644
--- a/data/binding/queue.go
+++ b/data/binding/queue.go
@@ -19,7 +19,7 @@ func makeInfiniteQueue() (chan<- *itemData, <-chan *itemData) {
 	in := make(chan *itemData)
 	out := make(chan *itemData)
 	go func() {
-		var queued []*itemData
+		queued := make([]*itemData, 0, 1024)
 		pending := func() chan *itemData {
 			if len(queued) == 0 {
 				return nil