refactor: verify started state for doing filter operations

waku/v2/protocol/filter/client.go

@@ -8,6 +8,7 @@ import (
 	"math"
 	"net/http"
 	"sync"
+	"sync/atomic"
 
 	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/network"
@@ -44,6 +45,7 @@ type WakuFilterLightNode struct {
 	log           *zap.Logger
 	subscriptions *SubscriptionsMap
 	pm            *peermanager.PeerManager
+	started       atomic.Bool
 }
 
 type ContentFilter struct {
@@ -56,6 +58,8 @@ type WakuFilterPushResult struct {
 	PeerID peer.ID
 }
 
+var errNotStarted = errors.New("filter is not started")
+
 // NewWakuFilterLightnode returns a new instance of Waku Filter struct setup according to the chosen parameter and options
 // Takes an optional peermanager if WakuFilterLightnode is being created along with WakuNode.
 // If using libp2p host, then pass peermanager as nil
@@ -78,6 +82,10 @@ func (wf *WakuFilterLightNode) SetHost(h host.Host) {
 }
 
 func (wf *WakuFilterLightNode) Start(ctx context.Context) error {
+	if !wf.started.CompareAndSwap(false, true) {
+		return nil // Already started
+	}
+
 	wf.wg.Wait() // Wait for any goroutines to stop
 
 	ctx, cancel := context.WithCancel(ctx)
@@ -94,7 +102,7 @@ func (wf *WakuFilterLightNode) Start(ctx context.Context) error {
 
 // Stop unmounts the filter protocol
 func (wf *WakuFilterLightNode) Stop() {
-	if wf.cancel == nil {
+	if !wf.started.CompareAndSwap(true, false) {
 		return
 	}
 
@@ -206,6 +214,10 @@ func (wf *WakuFilterLightNode) request(ctx context.Context, params *FilterSubscr
 
 // Subscribe setups a subscription to receive messages that match a specific content filter
 func (wf *WakuFilterLightNode) Subscribe(ctx context.Context, contentFilter ContentFilter, opts ...FilterSubscribeOption) (*SubscriptionDetails, error) {
+	if !wf.isStarted() {
+		return nil, errNotStarted
+	}
+
 	if contentFilter.Topic == "" {
 		return nil, errors.New("topic is required")
 	}
@@ -244,6 +256,10 @@ func (wf *WakuFilterLightNode) Subscribe(ctx context.Context, contentFilter Cont
 
 // FilterSubscription is used to obtain an object from which you could receive messages received via filter protocol
 func (wf *WakuFilterLightNode) FilterSubscription(peerID peer.ID, contentFilter ContentFilter) (*SubscriptionDetails, error) {
+	if !wf.isStarted() {
+		return nil, errNotStarted
+	}
+
 	if !wf.subscriptions.Has(peerID, contentFilter.Topic, contentFilter.ContentTopics...) {
 		return nil, errors.New("subscription does not exist")
 	}
@@ -263,6 +279,10 @@ func (wf *WakuFilterLightNode) getUnsubscribeParameters(opts ...FilterUnsubscrib
 }
 
 func (wf *WakuFilterLightNode) Ping(ctx context.Context, peerID peer.ID) error {
+	if !wf.isStarted() {
+		return errNotStarted
+	}
+
 	return wf.request(
 		ctx,
 		&FilterSubscribeParameters{selectedPeer: peerID},
@@ -271,10 +291,18 @@ func (wf *WakuFilterLightNode) Ping(ctx context.Context, peerID peer.ID) error {
 }
 
 func (wf *WakuFilterLightNode) IsSubscriptionAlive(ctx context.Context, subscription *SubscriptionDetails) error {
+	if !wf.isStarted() {
+		return errNotStarted
+	}
+
 	return wf.Ping(ctx, subscription.PeerID)
 }
 
 func (wf *WakuFilterLightNode) Subscriptions() []*SubscriptionDetails {
+	if !wf.isStarted() {
+		return nil
+	}
+
 	wf.subscriptions.RLock()
 	defer wf.subscriptions.RUnlock()
 
@@ -324,6 +352,10 @@ func (wf *WakuFilterLightNode) cleanupSubscriptions(peerID peer.ID, contentFilte
 
 // Unsubscribe is used to stop receiving messages from a peer that match a content filter
 func (wf *WakuFilterLightNode) Unsubscribe(ctx context.Context, contentFilter ContentFilter, opts ...FilterUnsubscribeOption) (<-chan WakuFilterPushResult, error) {
+	if !wf.isStarted() {
+		return nil, errNotStarted
+	}
+
 	if contentFilter.Topic == "" {
 		return nil, errors.New("topic is required")
 	}
@@ -401,6 +433,10 @@ func (wf *WakuFilterLightNode) Unsubscribe(ctx context.Context, contentFilter Co
 
 // Unsubscribe is used to stop receiving messages from a peer that match a content filter
 func (wf *WakuFilterLightNode) UnsubscribeWithSubscription(ctx context.Context, sub *SubscriptionDetails, opts ...FilterUnsubscribeOption) (<-chan WakuFilterPushResult, error) {
+	if !wf.isStarted() {
+		return nil, errNotStarted
+	}
+
 	var contentTopics []string
 	for k := range sub.ContentTopics {
 		contentTopics = append(contentTopics, k)
@@ -413,6 +449,10 @@ func (wf *WakuFilterLightNode) UnsubscribeWithSubscription(ctx context.Context,
 
 // UnsubscribeAll is used to stop receiving messages from peer(s). It does not close subscriptions
 func (wf *WakuFilterLightNode) UnsubscribeAll(ctx context.Context, opts ...FilterUnsubscribeOption) (<-chan WakuFilterPushResult, error) {
+	if !wf.isStarted() {
+		return nil, errNotStarted
+	}
+
 	params, err := wf.getUnsubscribeParameters(opts...)
 	if err != nil {
 		return nil, err
@@ -466,3 +506,7 @@ func (wf *WakuFilterLightNode) UnsubscribeAll(ctx context.Context, opts ...Filte
 
 	return resultChan, nil
 }
+
+func (wf *WakuFilterLightNode) isStarted() bool {
+	return wf.started.Load()
+}