threads: debounce client-side thread building

Debounce client-side thread building in the message store. Debouncing is
useful when multiple messages are loaded, i.e. when scrolling with
PgUp/PgDown.

Without the debouncing, all client-side threads will be built everytime
the message store is updated which creates a noticable lag in the
message list ui when client-side threading is activated.

The default debouncing delay can be changed by changing
'client-threads-delay' in the UI config section.

Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

2 files changed, 27 insertions, 8 deletions

diff --git a/lib/msgstore.go b/lib/msgstore.go
index 61a6dd44..9d7f3afb 100644
--- a/lib/msgstore.go
+++ b/lib/msgstore.go
@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"git.sr.ht/~rjarry/aerc/lib/sort"
+	"git.sr.ht/~rjarry/aerc/logging"
 	"git.sr.ht/~rjarry/aerc/models"
 	"git.sr.ht/~rjarry/aerc/worker/types"
 )
@@ -53,8 +54,8 @@ type MessageStore struct {
 	triggerNewEmail        func(*models.MessageInfo)
 	triggerDirectoryChange func()
 
-	dirInfoUpdateDebounce *time.Timer
-	dirInfoUpdateDelay    time.Duration
+	threadBuilderDebounce *time.Timer
+	threadBuilderDelay    time.Duration
 }
 
 const MagicUid = 0xFFFFFFFF
@@ -62,12 +63,10 @@ const MagicUid = 0xFFFFFFFF
 func NewMessageStore(worker *types.Worker,
 	dirInfo *models.DirectoryInfo,
 	defaultSortCriteria []*types.SortCriterion,
-	thread bool, clientThreads bool,
+	thread bool, clientThreads bool, clientThreadsDelay time.Duration,
 	triggerNewEmail func(*models.MessageInfo),
 	triggerDirectoryChange func()) *MessageStore {
 
-	dirInfoUpdateDelay := 5 * time.Second
-
 	if !dirInfo.Caps.Thread {
 		clientThreads = true
 	}
@@ -95,8 +94,7 @@ func NewMessageStore(worker *types.Worker,
 		triggerNewEmail:        triggerNewEmail,
 		triggerDirectoryChange: triggerDirectoryChange,
 
-		dirInfoUpdateDelay:    dirInfoUpdateDelay,
-		dirInfoUpdateDebounce: time.NewTimer(dirInfoUpdateDelay),
+		threadBuilderDelay: clientThreadsDelay,
 	}
 }
 
@@ -386,7 +384,17 @@ func (store *MessageStore) runThreadBuilder() {
 			store.builder.Update(msg)
 		}
 	}
-	store.Threads = store.builder.Threads(store.uids)
+	if store.threadBuilderDebounce != nil {
+		if store.threadBuilderDebounce.Stop() {
+			logging.Infof("thread builder debounced")
+		}
+	}
+	store.threadBuilderDebounce = time.AfterFunc(store.threadBuilderDelay, func() {
+		store.Threads = store.builder.Threads(store.uids)
+		if store.onUpdate != nil {
+			store.onUpdate(store)
+		}
+	})
 }
 
 func (store *MessageStore) Delete(uids []uint32,
diff --git a/lib/threadbuilder.go b/lib/threadbuilder.go
index 59abd2f6..ce56afe6 100644
--- a/lib/threadbuilder.go
+++ b/lib/threadbuilder.go
@@ -1,6 +1,7 @@
 package lib
 
 import (
+	"sync"
 	"time"
 
 	"git.sr.ht/~rjarry/aerc/logging"
@@ -10,6 +11,7 @@ import (
 )
 
 type ThreadBuilder struct {
+	sync.Mutex
 	threadBlocks   map[uint32]jwz.Threadable
 	messageidToUid map[string]uint32
 	seen           map[uint32]bool
@@ -27,6 +29,9 @@ func NewThreadBuilder() *ThreadBuilder {
 
 // Uids returns the uids in threading order
 func (builder *ThreadBuilder) Uids() []uint32 {
+	builder.Lock()
+	defer builder.Unlock()
+
 	if builder.threadedUids == nil {
 		return []uint32{}
 	}
@@ -35,6 +40,9 @@ func (builder *ThreadBuilder) Uids() []uint32 {
 
 // Update updates the thread builder with a new message header
 func (builder *ThreadBuilder) Update(msg *models.MessageInfo) {
+	builder.Lock()
+	defer builder.Unlock()
+
 	if msg != nil {
 		if threadable := newThreadable(msg); threadable != nil {
 			builder.messageidToUid[threadable.MessageThreadID()] = msg.Uid
@@ -45,6 +53,9 @@ func (builder *ThreadBuilder) Update(msg *models.MessageInfo) {
 
 // Threads returns a slice of threads for the given list of uids
 func (builder *ThreadBuilder) Threads(uids []uint32) []*types.Thread {
+	builder.Lock()
+	defer builder.Unlock()
+
 	start := time.Now()
 
 	threads := builder.buildAercThreads(builder.generateStructure(uids), uids)