Launch a coroutines job for each event

Author: takahirom

README.md

@@ -97,18 +97,16 @@ TimetableScreen ----> timetableScreenPresenter -> sessionsRepository
 ```kotlin
 @Composable
 fun timetableScreenPresenter(
-    events: Flow<TimetableScreenEvent>,
+    events: EventEmitter<TimetableScreenEvent>,
     sessionsRepository: SessionsRepository = localSessionsRepository(),
 ): TimetableScreenUiState = providePresenterDefaults { userMessageStateHolder ->
     ...
-    SafeLaunchedEffect(Unit) {
-        events.collect { event ->
-            when (event) {
-                is Bookmark -> {
-                    sessionsRepository.toggleBookmark(event.timetableItem.id)
-                }
-                ...
+    EventEffect(Unit) { event ->
+        when (event) {
+            is Bookmark -> {
+                sessionsRepository.toggleBookmark(event.timetableItem.id)
             }
+            ...
         }
     }
     ...
@@ -176,7 +174,7 @@ SessionsRepository ----> timetableScreenPresenter
 ```kotlin
 @Composable
 fun timetableScreenPresenter(
-    events: Flow<TimetableScreenEvent>,
+    events: EventEmitter<TimetableScreenEvent>,
     sessionsRepository: SessionsRepository = localSessionsRepository(),
 ): TimetableScreenUiState = providePresenterDefaults { userMessageStateHolder ->
     // Sessions are updated in the timetable() function
@@ -189,10 +187,8 @@ fun timetableScreenPresenter(
         ),
     )
     ...
-    SafeLaunchedEffect(Unit) {
-        events.collect { event ->
-            ...
-        }
+    EventEffect(events) { event ->
+        ...
     }
     TimetableScreenUiState(
         contentUiState = timetableUiState,

core/common/src/commonMain/kotlin/io/github/droidkaigi/confsched/compose/EventEmitter.kt

@@ -0,0 +1,30 @@
+package io.github.droidkaigi.confsched.compose
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.launch
+
+typealias EventFlow<T> = MutableSharedFlow<T>
+
+@Composable
+fun <T> rememberEventFlow(): EventFlow<T> {
+    return remember {
+        MutableSharedFlow(extraBufferCapacity = 20)
+    }
+}
+
+@Composable
+fun <EVENT> EventEffect(
+    eventFlow: EventFlow<EVENT>,
+    block: suspend CoroutineScope.(EVENT) -> Unit,
+) {
+    SafeLaunchedEffect(eventFlow) {
+        eventFlow.collect { event ->
+            launch {
+                block(event)
+            }
+        }
+    }
+}

core/common/src/commonMain/kotlin/io/github/droidkaigi/confsched/compose/EventFlow.kt

@@ -20,7 +20,7 @@ import androidx.compose.ui.platform.testTag
 import androidx.navigation.NavGraphBuilder
 import androidx.navigation.compose.composable
 import conference_app_2024.feature.contributors.generated.resources.contributor_title
-import io.github.droidkaigi.confsched.compose.rememberEventEmitter
+import io.github.droidkaigi.confsched.compose.rememberEventFlow
 import io.github.droidkaigi.confsched.contributors.component.ContributorsItem
 import io.github.droidkaigi.confsched.droidkaigiui.SnackbarMessageEffect
 import io.github.droidkaigi.confsched.droidkaigiui.UserMessageStateHolder
@@ -65,7 +65,7 @@ fun ContributorsScreen(
     modifier: Modifier = Modifier,
     isTopAppBarHidden: Boolean = false,
 ) {
-    val eventEmitter = rememberEventEmitter<ContributorsScreenEvent>()
+    val eventEmitter = rememberEventFlow<ContributorsScreenEvent>()
     val uiState = contributorsScreenPresenter(
         events = eventEmitter,
     )

feature/contributors/src/commonMain/kotlin/io/github/droidkaigi/confsched/contributors/ContributorsScreen.kt

@@ -3,23 +3,21 @@ package io.github.droidkaigi.confsched.contributors
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.rememberUpdatedState
-import io.github.droidkaigi.confsched.compose.SafeLaunchedEffect
+import io.github.droidkaigi.confsched.compose.EventEffect
+import io.github.droidkaigi.confsched.compose.EventFlow
 import io.github.droidkaigi.confsched.droidkaigiui.providePresenterDefaults
 import io.github.droidkaigi.confsched.model.ContributorsRepository
 import io.github.droidkaigi.confsched.model.localContributorsRepository
-import kotlinx.coroutines.flow.Flow
 
 sealed interface ContributorsScreenEvent
 
 @Composable
 fun contributorsScreenPresenter(
-    events: Flow<ContributorsScreenEvent>,
+    events: EventFlow<ContributorsScreenEvent>,
     contributorsRepository: ContributorsRepository = localContributorsRepository(),
 ): ContributorsUiState = providePresenterDefaults { userMessageStateHolder ->
     val contributors by rememberUpdatedState(contributorsRepository.contributors())
-    SafeLaunchedEffect(Unit) {
-        events.collect {
-        }
+    EventEffect(events) { event ->
     }
     ContributorsUiState(
         contributors = contributors,

feature/contributors/src/commonMain/kotlin/io/github/droidkaigi/confsched/contributors/ContributorsScreenPresenter.kt

@@ -1,5 +1,6 @@
 package io.github.droidkaigi.confsched.contributors
 
+import io.github.droidkaigi.confsched.compose.EventFlow
 import io.github.droidkaigi.confsched.data.Repositories
 import io.github.droidkaigi.confsched.droidkaigiui.composeViewController
 import io.github.droidkaigi.confsched.droidkaigiui.presenterStateFlow
@@ -22,7 +23,7 @@ fun contributorsViewController(
 @Suppress("unused")
 fun contributorsScreenPresenterStateFlow(
     repositories: Map<KClass<*>, Any>,
-    events: Flow<ContributorsScreenEvent>,
+    events: EventFlow<ContributorsScreenEvent>,
 ): Flow<ContributorsUiState> = presenterStateFlow(
     events = events,
     repositories = repositories,

feature/contributors/src/iosMain/kotlin/io/github/droidkaigi/confsched/contributors/ContributorsViewController.kt

@@ -29,7 +29,7 @@ import androidx.navigation.NavGraphBuilder
 import androidx.navigation.compose.composable
 import co.touchlab.kermit.Logger
 import conference_app_2024.feature.eventmap.generated.resources.eventmap
-import io.github.droidkaigi.confsched.compose.rememberEventEmitter
+import io.github.droidkaigi.confsched.compose.rememberEventFlow
 import io.github.droidkaigi.confsched.droidkaigiui.SnackbarMessageEffect
 import io.github.droidkaigi.confsched.droidkaigiui.UserMessageStateHolder
 import io.github.droidkaigi.confsched.droidkaigiui.component.AnimatedTextTopAppBar
@@ -81,7 +81,7 @@ fun EventMapScreen(
     modifier: Modifier = Modifier,
     contentPadding: PaddingValues = PaddingValues(),
 ) {
-    val eventEmitter = rememberEventEmitter<EventMapScreenEvent>()
+    val eventEmitter = rememberEventFlow<EventMapScreenEvent>()
     val uiState = eventMapScreenPresenter(
         events = eventEmitter,
     )

feature/eventmap/src/commonMain/kotlin/io/github/droidkaigi/confsched/eventmap/EventMapScreen.kt

@@ -3,23 +3,21 @@ package io.github.droidkaigi.confsched.eventmap
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.rememberUpdatedState
-import io.github.droidkaigi.confsched.compose.SafeLaunchedEffect
+import io.github.droidkaigi.confsched.compose.EventEffect
+import io.github.droidkaigi.confsched.compose.EventFlow
 import io.github.droidkaigi.confsched.droidkaigiui.providePresenterDefaults
 import io.github.droidkaigi.confsched.model.EventMapRepository
 import io.github.droidkaigi.confsched.model.localEventMapRepository
-import kotlinx.coroutines.flow.Flow
 
 sealed interface EventMapScreenEvent
 
 @Composable
 fun eventMapScreenPresenter(
-    events: Flow<EventMapScreenEvent>,
+    events: EventFlow<EventMapScreenEvent>,
     eventMapRepository: EventMapRepository = localEventMapRepository(),
 ): EventMapUiState = providePresenterDefaults { userMessageStateHolder ->
     val eventMap by rememberUpdatedState(eventMapRepository.eventMapEvents())
-    SafeLaunchedEffect(Unit) {
-        events.collect {
-        }
+    EventEffect(events) { event ->
     }
     EventMapUiState(
         eventMap = eventMap,

feature/eventmap/src/commonMain/kotlin/io/github/droidkaigi/confsched/eventmap/EventMapScreenPresenter.kt

@@ -25,8 +25,8 @@ import androidx.navigation.NavGraph.Companion.findStartDestination
 import androidx.navigation.NavGraphBuilder
 import androidx.navigation.compose.composable
 import conference_app_2024.feature.favorites.generated.resources.favorite
-import io.github.droidkaigi.confsched.compose.EventEmitter
-import io.github.droidkaigi.confsched.compose.rememberEventEmitter
+import io.github.droidkaigi.confsched.compose.EventFlow
+import io.github.droidkaigi.confsched.compose.rememberEventFlow
 import io.github.droidkaigi.confsched.designsystem.theme.KaigiTheme
 import io.github.droidkaigi.confsched.droidkaigiui.SnackbarMessageEffect
 import io.github.droidkaigi.confsched.droidkaigiui.UserMessageStateHolder
@@ -79,8 +79,8 @@ fun FavoritesScreen(
     onTimetableItemClick: (TimetableItem) -> Unit,
     modifier: Modifier = Modifier,
     contentPadding: PaddingValues = PaddingValues(),
-    eventEmitter: EventEmitter<FavoritesScreenEvent> = rememberEventEmitter(),
-    uiState: FavoritesScreenUiState = favoritesScreenPresenter(events = eventEmitter),
+    eventFlow: EventFlow<FavoritesScreenEvent> = rememberEventFlow(),
+    uiState: FavoritesScreenUiState = favoritesScreenPresenter(events = eventFlow),
 ) {
     val snackbarHostState = remember { SnackbarHostState() }
 
@@ -93,16 +93,16 @@ fun FavoritesScreen(
         snackbarHostState = snackbarHostState,
         onTimetableItemClick = onTimetableItemClick,
         onAllFilterChipClick = {
-            eventEmitter.tryEmit(FavoritesScreenEvent.AllFilter)
+            eventFlow.tryEmit(FavoritesScreenEvent.AllFilter)
         },
         onDay1FilterChipClick = {
-            eventEmitter.tryEmit(FavoritesScreenEvent.Day1Filter)
+            eventFlow.tryEmit(FavoritesScreenEvent.Day1Filter)
         },
         onDay2FilterChipClick = {
-            eventEmitter.tryEmit(FavoritesScreenEvent.Day2Filter)
+            eventFlow.tryEmit(FavoritesScreenEvent.Day2Filter)
         },
         onBookmarkClick = { timetableItem ->
-            eventEmitter.tryEmit(FavoritesScreenEvent.Bookmark(timetableItem))
+            eventFlow.tryEmit(FavoritesScreenEvent.Bookmark(timetableItem))
         },
         contentPadding = contentPadding,
         modifier = modifier,

feature/favorites/src/commonMain/kotlin/io/github/droidkaigi/confsched/favorites/FavoritesScreen.kt

@@ -6,7 +6,8 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.runtime.setValue
-import io.github.droidkaigi.confsched.compose.SafeLaunchedEffect
+import io.github.droidkaigi.confsched.compose.EventEffect
+import io.github.droidkaigi.confsched.compose.EventFlow
 import io.github.droidkaigi.confsched.droidkaigiui.providePresenterDefaults
 import io.github.droidkaigi.confsched.favorites.FavoritesScreenEvent.AllFilter
 import io.github.droidkaigi.confsched.favorites.FavoritesScreenEvent.Bookmark
@@ -26,7 +27,6 @@ import kotlinx.collections.immutable.PersistentSet
 import kotlinx.collections.immutable.toPersistentList
 import kotlinx.collections.immutable.toPersistentMap
 import kotlinx.collections.immutable.toPersistentSet
-import kotlinx.coroutines.flow.Flow
 
 sealed interface FavoritesScreenEvent {
     data class Bookmark(val timetableItem: TimetableItem) : FavoritesScreenEvent
@@ -38,7 +38,7 @@ sealed interface FavoritesScreenEvent {
 
 @Composable
 fun favoritesScreenPresenter(
-    events: Flow<FavoritesScreenEvent>,
+    events: EventFlow<FavoritesScreenEvent>,
     sessionsRepository: SessionsRepository = localSessionsRepository(),
 ): FavoritesScreenUiState = providePresenterDefaults { userMessageStateHolder ->
     val favoriteSessions by rememberUpdatedState(
@@ -56,33 +56,32 @@ fun favoritesScreenPresenter(
         ),
     )
 
-    SafeLaunchedEffect(Unit) {
-        events.collect { event ->
-            when (event) {
-                is Bookmark -> {
-                    sessionsRepository.toggleBookmark(event.timetableItem.id)
-                }
+    EventEffect(events) { event ->
+        when (event) {
+            is Bookmark -> {
+                sessionsRepository.toggleBookmark(event.timetableItem.id)
+            }
 
-                AllFilter -> {
-                    allFilterSelected = true
-                    currentDayFilters = emptySet()
-                }
+            AllFilter -> {
+                allFilterSelected = true
+                currentDayFilters = emptySet()
+            }
 
-                Day1Filter, Day2Filter -> {
-                    allFilterSelected = false
+            Day1Filter, Day2Filter -> {
+                allFilterSelected = false
 
-                    val dayType = if (event is Day1Filter) {
-                        ConferenceDay1
-                    } else {
-                        ConferenceDay2
-                    }
+                val dayType = if (event is Day1Filter) {
+                    ConferenceDay1
+                } else {
+                    ConferenceDay2
+                }
 
-                    currentDayFilters = if (currentDayFilters.contains(dayType) && currentDayFilters.size >= 2) {
+                currentDayFilters =
+                    if (currentDayFilters.contains(dayType) && currentDayFilters.size >= 2) {
                         currentDayFilters - dayType
                     } else {
                         currentDayFilters + dayType
                     }
-                }
             }
         }
     }