From b87fea7fb3d07d636af0bf7e81681bebc6a9fd42 Mon Sep 17 00:00:00 2001
From: Greg <gmp@wow.st>
Date: Fri, 25 Oct 2019 13:30:11 -0400
Subject: [PATCH] Do not connect to peripherals with outstanding connection
 attempts.

---
 ble_darwin.go | 86 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 54 insertions(+), 32 deletions(-)

diff --git a/ble_darwin.go b/ble_darwin.go
index 5607b77..1b85894 100644
--- a/ble_darwin.go
+++ b/ble_darwin.go
@@ -119,6 +119,7 @@ func (ps *Peripherals) Add(x Peripheral) bool {
 	}
 	//take ownership of this Objective-C object
 	x.p.Retain()
+	runtime.SetFinalizer(x.p, nil)
 	x.p.GC()
 	item := PeripheralListItem{p: x, seen: time.Now()}
 	ps.items = append(ps.items, item)
@@ -225,6 +226,9 @@ func (b *BLE) Scan() {
 	if b.state != (ns.CBManagerState)(ns.CBManagerStatePoweredOn) {
 		b.wantScan = true
 	} else {
+		b.peripherals.Lock()
+		b.peripherals.items = b.peripherals.items[:0]
+		b.peripherals.Unlock()
 		fmt.Printf("Go: Scanning\n")
 		b.cm.ScanForPeripheralsWithServices(nil, nil)
 	}
@@ -241,37 +245,51 @@ func (b *BLE) StopScan() {
 	b.cm.StopScan()
 }
 
-func connectTracker(b *BLE, x ConnectionListItem) {
+func connectTracker(b *BLE, x ConnectionListItem) bool {
 	fmt.Printf("connectTracker(): %s\n", x.p.Name)
-	tick := time.NewTicker(time.Second * 5)
-	select {
-	case <-b.connections.close:
-		fmt.Printf("Closing connection to %s\n", x.p.Name)
-		b.cm.CancelPeripheralConnection(x.p.p)
-	case <-tick.C:
-		fmt.Printf("Connection to %s timed out\n", x.p.Name)
-		b.cm.CancelPeripheralConnection(x.p.p)
-		b.connections.Lock()
-		for n, item := range b.connections.items {
-			if item.p.Identifier == x.p.Identifier {
-				b.connections.items = append(b.connections.items[:n], b.connections.items[n+1:]...)
-			}
-		}
-		b.connections.Unlock()
-		b.events <- ConnectTimeoutEvent{x.p}
-	case state := <-x.state:
-		fmt.Printf("connectTracker: state\n")
-		if state == "connected" {
-			fmt.Printf("--connected")
+	b.connections.Lock()
+	for _, item := range b.connections.items {
+		if item.p.Identifier == x.p.Identifier {
+			fmt.Printf("connectTracker(): already connecting to %s\n", x.p.Name)
+			b.connections.Unlock()
+			return false
 		}
 	}
+	b.connections.items = append(b.connections.items, x)
+	b.connections.Unlock()
+	fmt.Printf("BLE.Connect(): calling cm.ConnectPeripheral(%p)\n", x.p.p.Ptr())
+	b.cm.ConnectPeripheral(x.p.p, nil)
+
+	go func() {
+		tick := time.NewTicker(time.Second * 5)
+		select {
+		case <-b.connections.close:
+			fmt.Printf("connectTracker(): Closing connection to %s\n", x.p.Name)
+			b.cm.CancelPeripheralConnection(x.p.p)
+		case <-tick.C:
+			fmt.Printf("connectTracker(): Connection to %s timed out\n", x.p.Name)
+			b.cm.CancelPeripheralConnection(x.p.p)
+			b.connections.Lock()
+			for n, item := range b.connections.items {
+				if item.p.Identifier == x.p.Identifier {
+					b.connections.items = append(b.connections.items[:n], b.connections.items[n+1:]...)
+				}
+			}
+			b.connections.Unlock()
+			b.events <- ConnectTimeoutEvent{x.p}
+		case state := <-x.state:
+			fmt.Printf("connectTracker(): state %s\n", state)
+		}
+	}()
+	return true
 }
 
-func (b *BLE) Connect(p Peripheral) {
+func (b *BLE) Connect(p Peripheral) bool {
 	b.Lock()
 	if !b.ready {
 		b.Unlock()
-		return
+		fmt.Printf("--BLE not ready\n")
+		return false
 	}
 	b.Unlock()
 	if p.p == nil {
@@ -279,19 +297,19 @@ func (b *BLE) Connect(p Peripheral) {
 		ps := b.cm.RetrievePeripheralsWithIdentifiers(ns.NSArrayWithObjects(ns.NSUUIDAlloc().InitWithUUIDString(ns.NSStringWithGoString(p.Identifier))))
 		if x := (int)(ps.Count()); x > 0 {
 			fmt.Printf("--found %d\n", x)
-			p.p = ps.ObjectAtIndex(0).CBPeripheral()
+			cbp := ps.ObjectAtIndex(0).CBPeripheral()
+//NOTE: ns.ObjectAtIndex() calls SetFinalizer for us, which will be a problem
+//later when we call GC(), so we first clear the finalizer here.
+			runtime.SetFinalizer(cbp, nil)
+			p = newPeripheral(cbp)
 		} else {
 			fmt.Printf("--none found\n")
-			return
+			return false
 		}
 	}
 	item := ConnectionListItem{p, make(chan string)}
-	b.connections.Add(item)
-	go connectTracker(b, item)
-	//time.Sleep(time.Second/10)
-	fmt.Printf("BLE.Connect(): calling cm.ConnectPeripheral(%p)\n", p.p.Ptr())
-	b.cm.ConnectPeripheral(p.p, nil)
-	fmt.Printf("BLE.Connect() returned\n")
+	fmt.Printf("BLE.Connect() calling connectTracker\n")
+	return connectTracker(b, item)
 }
 
 func updateState(c *ns.CBCentralManager) {
@@ -319,11 +337,15 @@ func discoverPeripheral(c *ns.CBCentralManager, p *ns.CBPeripheral, d *ns.NSDict
 	b := cdLookup[c.Ptr()]
 	peripheral := newPeripheral(p)
 	peripheral.RSSI = (int)(rssi.IntValue())
+	_discoverPeripheral(b, peripheral)
+}
+
+func _discoverPeripheral(b *BLE, peripheral Peripheral) {
 	if peripheral.Name == "" {
 		return
 	}
 	if ok := b.peripherals.Add(peripheral); ok {
-		pdLookup[p.Ptr()] = b
+		pdLookup[peripheral.p.Ptr()] = b
 		b.events <- DiscoverPeripheralEvent{Peripheral: peripheral}
 	}
 }