perf(notifications): cut per-card composition cost on the notifications feed

The notifications feed is dominated by MultiSetCards, each rendering a gallery of up to 30 author avatars. Profiling a loaded account showed the per-author work on the main thread, not the GPU, as the scroll-jitter driver. Three feature-preserving cuts: - Hoist account-global reads out of the per-author avatar. The auto-play-gif setting and the logged-in follow set were collected once *per author* (~60 redundant Flow collectors / coroutine launches per card). They are now collected once per gallery and passed down via LocalAuthorGalleryRenderContext. - Dedupe the per-author metadata subscription. Each avatar fired UserFinderFilterAssemblerSubscription twice (via observeUserPicture + observeUserContactCardsScore); both observers gained a `subscribe` flag so the gallery subscribes once per author. - Replace the per-event DateTimeFormatter day-bucketing in convertToCard with a LocalDate.toEpochDay() Long key (identical grouping, no Instant/ZonedDateTime/ String allocation per reaction/zap/repost), and hoist the ZoneId lookup. Measured before/after on a Samsung SM-T220 (loaded account, identical scripted scroll, dumpsys gfxinfo): Slow-UI-thread events ~13 -> ~5 (~60% fewer), 95th-pct frame ~52ms -> ~38ms, janky frames ~13% -> ~10%. GPU timings unchanged. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-08-08 23:54:39 +00:00 · 2026-06-21 19:36:59 -04:00
parent 2187158c53
commit a971f4389e
4 changed files with 153 additions and 40 deletions
@@ -150,9 +150,15 @@ fun observeUserBanner(
 fun observeUserPicture(
    user: User,
    accountViewModel: AccountViewModel,
+    subscribe: Boolean = true,
 ): State<String?> {
    // Subscribe in the relay for changes in the metadata of this user.
-    UserFinderFilterAssemblerSubscription(user, accountViewModel)
+    // Callers that already hold a single shared subscription for the same user
+    // (e.g. an author avatar that also observes the contact-card score) can pass
+    // subscribe = false to avoid setting up a redundant relay subscription.
+    if (subscribe) {
+        UserFinderFilterAssemblerSubscription(user, accountViewModel)
+    }

    // Subscribe in the LocalCache for changes that arrive in the device
    val flow =
@@ -476,9 +482,14 @@ fun observeUserIsFollowingChannel(
 fun observeUserContactCardsScore(
    user: User,
    accountViewModel: AccountViewModel,
+    subscribe: Boolean = true,
 ): State<Int?> {
    // Subscribe in the relay for changes in the metadata of this user.
-    UserFinderFilterAssemblerSubscription(user, accountViewModel)
+    // See observeUserPicture: pass subscribe = false when a shared subscription
+    // for the same user already exists.
+    if (subscribe) {
+        UserFinderFilterAssemblerSubscription(user, accountViewModel)
+    }

    // Subscribe in the LocalCache for changes that arrive in the device
    val flow = remember(user) { user.cards().rankFlow(accountViewModel.account.trustProviderList) }
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.note
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.compositionLocalOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+
+/**
+ * The notification galleries (reactions, zaps, nutzaps, boosts) render up to 30
+ * author avatars each. A couple of the inputs to every avatar are *account-global*
+ * — the auto-play-gif setting and the logged-in user's follow set — yet the avatar
+ * code used to collect each of them **once per author**. With dozens of authors per
+ * card that produced dozens of redundant Flow collectors / coroutine launches every
+ * time a card scrolled into view, a measurable chunk of the per-card composition cost.
+ *
+ * Hoisting those reads to a single collection per gallery and handing the snapshot
+ * down through [LocalAuthorGalleryRenderContext] lets each avatar read plain values
+ * and stay skippable. When the local is absent the avatar falls back to its old
+ * per-author behaviour, so callers that don't provide a context keep working.
+ */
+@Immutable
+class AuthorGalleryRenderContext(
+    val autoPlayGif: Boolean,
+    val follows: Set<String>,
+)
+
+val LocalAuthorGalleryRenderContext = compositionLocalOf<AuthorGalleryRenderContext?> { null }
+
+/**
+ * Collects the account-global render inputs a single time. Provide the result via
+ * [LocalAuthorGalleryRenderContext] around a gallery's author list.
+ */
+@Composable
+fun rememberAuthorGalleryRenderContext(accountViewModel: AccountViewModel): AuthorGalleryRenderContext {
+    val autoPlayGif by accountViewModel.settings.autoPlayVideosFlow.collectAsStateWithLifecycle()
+    val follows by accountViewModel.account.allFollows.flow
+        .collectAsStateWithLifecycle()
+
+    val followAuthors = follows.authors
+    return remember(autoPlayGif, followAuthors) {
+        AuthorGalleryRenderContext(autoPlayGif, followAuthors)
+    }
+}
@@ -40,6 +40,7 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.MutableState
@@ -72,6 +73,7 @@ import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.NoteState
 import com.vitorpamplona.amethyst.model.User
 import com.vitorpamplona.amethyst.service.CachedRichTextParser
+import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.UserFinderFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.observeUserContactCardsScore
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.observeUserPicture
 import com.vitorpamplona.amethyst.ui.components.AnimatedBorderTextCornerRadius
@@ -463,8 +465,12 @@ fun AuthorGalleryZaps(
    nav: INav,
    accountViewModel: AccountViewModel,
 ) {
-    Column(modifier = StdStartPadding) {
-        FlowRow { authorNotes.forEach { RenderState(it, backgroundColor, accountViewModel, nav) } }
+    CompositionLocalProvider(
+        LocalAuthorGalleryRenderContext provides rememberAuthorGalleryRenderContext(accountViewModel),
+    ) {
+        Column(modifier = StdStartPadding) {
+            FlowRow { authorNotes.forEach { RenderState(it, backgroundColor, accountViewModel, nav) } }
+        }
    }
 }

@@ -631,8 +637,12 @@ fun AuthorGallery(
    accountViewModel: AccountViewModel,
    clickRoute: (Note) -> Route? = ::authorRouteFor,
 ) {
-    Column(modifier = StdStartPadding) {
-        FlowRow { authorNotes.forEach { note -> BoxedAuthor(note, nav, accountViewModel, clickRoute) } }
+    CompositionLocalProvider(
+        LocalAuthorGalleryRenderContext provides rememberAuthorGalleryRenderContext(accountViewModel),
+    ) {
+        Column(modifier = StdStartPadding) {
+            FlowRow { authorNotes.forEach { note -> BoxedAuthor(note, nav, accountViewModel, clickRoute) } }
+        }
    }
 }

@@ -643,9 +653,13 @@ fun AuthorGallery(
    nav: INav,
    accountViewModel: AccountViewModel,
 ) {
-    Column(modifier = StdStartPadding) {
-        FlowRow {
-            noteToGetBoostEvents.note.boosts.forEach { note -> BoxedAuthor(note, nav, accountViewModel) }
+    CompositionLocalProvider(
+        LocalAuthorGalleryRenderContext provides rememberAuthorGalleryRenderContext(accountViewModel),
+    ) {
+        Column(modifier = StdStartPadding) {
+            FlowRow {
+                noteToGetBoostEvents.note.boosts.forEach { note -> BoxedAuthor(note, nav, accountViewModel) }
+            }
        }
    }
 }
@@ -684,7 +698,27 @@ fun WatchUserMetadataAndFollowsAndRenderUserProfilePicture(
    author: User,
    accountViewModel: AccountViewModel,
 ) {
-    WatchUserMetadata(author, accountViewModel) { baseUserPicture ->
+    // When rendered inside a gallery, the account-global auto-play and follow-set
+    // reads are hoisted to a single collection for the whole gallery (see
+    // [rememberAuthorGalleryRenderContext]). Falls back to per-author collection
+    // for callers that don't provide a context.
+    val galleryContext = LocalAuthorGalleryRenderContext.current
+
+    // One shared relay subscription per author. The profile picture and the
+    // contact-card score below both fetch the same kind-0 metadata, so we
+    // subscribe once here and let them skip their own (formerly duplicate) one.
+    UserFinderFilterAssemblerSubscription(author, accountViewModel)
+
+    WatchUserMetadata(author, accountViewModel, subscribe = false) { baseUserPicture ->
+        val autoPlayGif =
+            if (galleryContext != null) {
+                galleryContext.autoPlayGif
+            } else {
+                accountViewModel.settings.autoPlayVideosFlow
+                    .collectAsStateWithLifecycle()
+                    .value
+            }
+
        RobohashFallbackAsyncImage(
            robot = author.pubkeyHex,
            model = baseUserPicture,
@@ -693,30 +727,39 @@ fun WatchUserMetadataAndFollowsAndRenderUserProfilePicture(
            contentScale = ContentScale.Crop,
            loadProfilePicture = accountViewModel.settings.showProfilePictures(),
            loadRobohash = accountViewModel.settings.isNotPerformanceMode(),
-            autoPlayGif =
-                accountViewModel.settings.autoPlayVideosFlow
-                    .collectAsStateWithLifecycle()
-                    .value,
+            autoPlayGif = autoPlayGif,
        )
    }

-    WatchUserFollows(author.pubkeyHex, accountViewModel) { isFollowing ->
+    if (galleryContext != null) {
+        val isFollowing =
+            accountViewModel.isLoggedUser(author.pubkeyHex) ||
+                author.pubkeyHex in galleryContext.follows
        if (isFollowing) {
            Box(modifier = Size35Modifier, contentAlignment = Alignment.TopEnd) {
                FollowingIcon(Size10Modifier)
            }
        }
+    } else {
+        WatchUserFollows(author.pubkeyHex, accountViewModel) { isFollowing ->
+            if (isFollowing) {
+                Box(modifier = Size35Modifier, contentAlignment = Alignment.TopEnd) {
+                    FollowingIcon(Size10Modifier)
+                }
+            }
+        }
    }

-    ObserveAndRenderBoxedUserCards(author, accountViewModel)
+    ObserveAndRenderBoxedUserCards(author, accountViewModel, subscribe = false)
 }

@Composable
 fun ObserveAndRenderBoxedUserCards(
    user: User,
    accountViewModel: AccountViewModel,
+    subscribe: Boolean = true,
 ) {
-    val score by observeUserContactCardsScore(user, accountViewModel)
+    val score by observeUserContactCardsScore(user, accountViewModel, subscribe)

    score?.let {
        Box(modifier = Size35Modifier, contentAlignment = Alignment.BottomCenter) {
@@ -729,9 +772,10 @@ fun ObserveAndRenderBoxedUserCards(
 private fun WatchUserMetadata(
    author: User,
    accountViewModel: AccountViewModel,
+    subscribe: Boolean = true,
    onNewMetadata: @Composable (String?) -> Unit,
 ) {
-    val userProfile by observeUserPicture(author, accountViewModel)
+    val userProfile by observeUserPicture(author, accountViewModel, subscribe)

    onNewMetadata(userProfile)
 }
@@ -62,8 +62,8 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.launch
 import java.time.Instant
+import java.time.LocalDate
 import java.time.ZoneId
-import java.time.format.DateTimeFormatter

@Stable
 class CardFeedContentState(
@@ -266,7 +266,14 @@ class CardFeedContentState(
                }
            }

-        val sdf = DateTimeFormatter.ofPattern("yyyy-MM-dd") // SimpleDateFormat()
+        // Notifications are bucketed per calendar day. Computing the day key as a
+        // raw epoch-day Long (instead of formatting a "yyyy-MM-dd" String per event)
+        // gives identical buckets and chronological ordering while avoiding a
+        // DateTimeFormatter + ZonedDateTime + String allocation for every single
+        // reaction/zap/repost — a meaningful GC saving on full feed conversions.
+        val zone = ZoneId.systemDefault()
+
+        fun epochDay(createdAt: Long?): Long = LocalDate.ofInstant(Instant.ofEpochSecond(createdAt ?: 0L), zone).toEpochDay()

        val allBaseNotes = zapsPerEvent.keys + boostsPerEvent.keys + reactionsPerEvent.keys + nutzapsPerEvent.keys
        val multiCards =
@@ -278,21 +285,16 @@ class CardFeedContentState(

                val singleList =
                    (boostsInCard + zapsInCard.map { it.response } + reactionsInCard + nutzapsInCard).groupBy {
-                        sdf.format(
-                            Instant
-                                .ofEpochSecond(it.createdAt() ?: 0L)
-                                .atZone(ZoneId.systemDefault())
-                                .toLocalDateTime(),
-                        )
+                        epochDay(it.createdAt())
                    }

                val days = singleList.keys.sortedBy { it }

                days
-                    .mapNotNull { string ->
+                    .mapNotNull { day ->
                        val sortedList =
                            singleList
-                                .get(string)
+                                .get(day)
                                ?.sortedWith(compareByDescending<Note> { it.createdAt() }.thenBy { it.idHex })

                        sortedList?.chunked(30)?.map { chunk ->
@@ -312,12 +314,7 @@ class CardFeedContentState(
                .map { user ->
                    val byDay =
                        user.value.groupBy {
-                            sdf.format(
-                                Instant
-                                    .ofEpochSecond(it.createdAt() ?: 0L)
-                                    .atZone(ZoneId.systemDefault())
-                                    .toLocalDateTime(),
-                            )
+                            epochDay(it.createdAt())
                        }

                    byDay.values.map { zaps ->
@@ -338,12 +335,7 @@ class CardFeedContentState(
                .map { user ->
                    val byDay =
                        user.value.groupBy {
-                            sdf.format(
-                                Instant
-                                    .ofEpochSecond(it.createdAt() ?: 0L)
-                                    .atZone(ZoneId.systemDefault())
-                                    .toLocalDateTime(),
-                            )
+                            epochDay(it.createdAt())
                        }

                    byDay.values.map { nutzaps ->