Performance refactors for Posts feed

app/build.gradle.kts

@@ -29,7 +29,7 @@ android {
             useSupportLibrary = true
         }
         ksp {
-           arg("room.schemaLocation", "$projectDir/schemas")
+            arg("room.schemaLocation", "$projectDir/schemas")
         }
     }
 

app/src/main/java/com/jerboa/Utils.kt

@@ -867,7 +867,14 @@ fun getCommentIdDepthFromPath(
 }
 
 fun nsfwCheck(postView: PostView): Boolean {
-    return postView.post.nsfw || postView.community.nsfw
+    return nsfwCheck(postView.post, postView.community)
+}
+
+fun nsfwCheck(
+    post: Post,
+    community: Community,
+): Boolean {
+    return post.nsfw || community.nsfw
 }
 
 @RequiresApi(Build.VERSION_CODES.Q)

app/src/main/java/com/jerboa/datatypes/SampleData.kt

@@ -49,7 +49,7 @@ val samplePost =
         community_id = 14681,
         removed = false,
         locked = false,
-        published = "2022-01-01T09:53:46.904077",
+        published = "2022-01-01T09:53:46.904077Z",
         updated = null,
         deleted = false,
         nsfw = false,
@@ -74,7 +74,7 @@ val sampleLinkPost =
         community_id = 14681,
         removed = false,
         locked = true,
-        published = "2022-01-01T09:53:46.904077",
+        published = "2022-01-01T09:53:46.904077Z",
         updated = null,
         deleted = false,
         nsfw = false,
@@ -99,7 +99,7 @@ val sampleLinkNoThumbnailPost =
         community_id = 14681,
         removed = false,
         locked = false,
-        published = "2022-01-01T09:53:46.904077",
+        published = "2022-01-01T09:53:46.904077Z",
         updated = null,
         deleted = false,
         nsfw = false,
@@ -124,7 +124,7 @@ val sampleImagePost =
         community_id = 14681,
         removed = false,
         locked = false,
-        published = "2022-01-01T09:53:46.904077",
+        published = "2022-01-01T09:53:46.904077Z",
         updated = null,
         deleted = false,
         nsfw = false,
@@ -149,7 +149,7 @@ val sampleMarkdownPost =
         community_id = 14681,
         removed = false,
         locked = false,
-        published = "2022-01-01T09:53:46.904077",
+        published = "2022-01-01T09:53:46.904077Z",
         updated = null,
         deleted = false,
         nsfw = false,
@@ -171,8 +171,8 @@ val samplePerson =
         display_name = "No longer Homeless",
         avatar = "https://lemmy.ml/pictrs/image/LqURxPzFNW.jpg",
         banned = false,
-        published = "2021-08-08T01:47:44.437708",
-        updated = "2021-10-11T07:14:53.548707",
+        published = "2021-08-08T01:47:44.437708Z",
+        updated = "2021-10-11T07:14:53.548707Z",
         actor_id = "https://lemmy.ml/u/homeless",
         bio =
             "This is my bio.\n\nI like trucks, trains, and geese. This is *one* longer line " +
@@ -194,8 +194,8 @@ val samplePerson2 =
         display_name = null,
         avatar = "https://lemmy.ml/pictrs/image/kykidJ1ssM.jpg",
         banned = false,
-        published = "2021-08-08T01:47:44.437708",
-        updated = "2021-10-11T07:14:53.548707",
+        published = "2021-08-08T01:47:44.437708Z",
+        updated = "2021-10-11T07:14:53.548707Z",
         actor_id = "https://lemmy.ml/u/homeless",
         bio = null,
         local = false,
@@ -213,8 +213,8 @@ val samplePerson3 =
         name = "witch_power",
         display_name = null,
         banned = false,
-        published = "2021-08-08T01:47:44.437708",
-        updated = "2021-10-11T07:14:53.548707",
+        published = "2021-08-08T01:47:44.437708Z",
+        updated = "2021-10-11T07:14:53.548707Z",
         actor_id = "https://lemmy.ml/u/witch_power",
         bio = null,
         local = true,
@@ -260,8 +260,8 @@ val sampleCommunity =
         title = "Socialism",
         description = "This is the r/socialism community",
         removed = false,
-        published = "2019-04-30T13:28:35.965035",
-        updated = "2021-01-25T16:27:15.804739",
+        published = "2019-04-30T13:28:35.965035Z",
+        updated = "2021-01-25T16:27:15.804739Z",
         deleted = false,
         nsfw = false,
         actor_id = "https://lemmy.ml/c/socialism",
@@ -282,7 +282,7 @@ val samplePostAggregates =
         score = 8,
         upvotes = 8,
         downvotes = 0,
-        published = "2022-01-02T04:02:44.592929",
+        published = "2022-01-02T04:02:44.592929Z",
     )
 
 val samplePostView =
@@ -381,8 +381,8 @@ val sampleComment =
                 "work" +
                 ".\n\nIts kind of a long comment\n\nbut I don't want...",
         removed = false,
-        published = "2022-01-07T03:12:26.398434",
-        updated = "2022-01-07T03:15:37.360888",
+        published = "2022-01-07T03:12:26.398434Z",
+        updated = "2022-01-07T03:15:37.360888Z",
         deleted = false,
         ap_id = "https://midwest.social/comment/24621",
         local = false,
@@ -399,8 +399,8 @@ val sampleReplyComment =
         path = "0.1.2",
         content = "This is a reply comment.\n\n# This is a header\n\n- list one\n\n- list two",
         removed = false,
-        published = "2022-01-07T04:12:26.398434",
-        updated = "2022-01-07T03:15:37.360888",
+        published = "2022-01-07T04:12:26.398434Z",
+        updated = "2022-01-07T03:15:37.360888Z",
         deleted = false,
         ap_id = "https://midwest.social/comment/24622",
         local = false,
@@ -416,8 +416,8 @@ val sampleSecondReplyComment =
         path = "0.1.2.3",
         content = "This is a sub-reply comment, mmmmk",
         removed = false,
-        published = "2022-01-07T04:12:26.398434",
-        updated = "2022-01-07T03:15:37.360888",
+        published = "2022-01-07T04:12:26.398434Z",
+        updated = "2022-01-07T03:15:37.360888Z",
         deleted = false,
         ap_id = "https://midwest.social/comment/24622",
         local = false,
@@ -431,7 +431,7 @@ val sampleCommentAggregates =
         score = 8,
         upvotes = 12,
         downvotes = 4,
-        published = "2022-01-02T04:02:44.592929",
+        published = "2022-01-02T04:02:44.592929Z",
         child_count = 0,
     )
 
@@ -486,7 +486,7 @@ val sampleCommentReply =
         recipient_id = 20,
         comment_id = 42,
         read = false,
-        published = "2022-01-01T09:53:46.904077",
+        published = "2022-01-01T09:53:46.904077Z",
     )
 
 val samplePersonMention =
@@ -495,7 +495,7 @@ val samplePersonMention =
         recipient_id = 20,
         comment_id = 42,
         read = false,
-        published = "2022-01-01T09:53:46.904077",
+        published = "2022-01-01T09:53:46.904077Z",
     )
 
 val sampleCommentReplyView =
@@ -534,7 +534,7 @@ val samplePersonMentionView =
 
 val sampleCommunityAggregates =
     CommunityAggregates(
-        published = "2022-01-02T04:02:44.592929",
+        published = "2022-01-02T04:02:44.592929Z",
         community_id = 834,
         subscribers = 52,
         subscribers_local = 21,
@@ -576,8 +576,8 @@ val samplePrivateMessage =
         content = "A message from *me* to **you**",
         deleted = false,
         read = false,
-        published = "2022-01-07T04:12:26.398434",
-        updated = "2022-01-07T03:15:37.360888",
+        published = "2022-01-07T04:12:26.398434Z",
+        updated = "2022-01-07T03:15:37.360888Z",
         ap_id = "https://midwest.social/comment/24622",
         local = false,
     )
@@ -595,8 +595,8 @@ val sampleSite =
         name = "Lemmy.ml",
         sidebar = "# Hello!\n\n**This is** lemmy's sidebar",
         description = "A general purpose instance for lemmy",
-        published = "2022-01-07T04:12:26.398434",
-        updated = "2022-01-07T03:15:37.360888",
+        published = "2022-01-07T04:12:26.398434Z",
+        updated = "2022-01-07T03:15:37.360888Z",
         icon = "https://lemmy.ml/pictrs/image/LqURxPzFNW.jpg",
         banner = "https://lemmy.ml/pictrs/image/386rk5OYWS.jpg",
         actor_id = "https://lemmy.ml",

app/src/main/java/com/jerboa/feed/FeedController.kt

@@ -0,0 +1,74 @@
+package com.jerboa.feed
+
+import android.util.Log
+import androidx.compose.runtime.mutableStateListOf
+
+open class FeedController<T> {
+    protected val items = mutableStateListOf<T>()
+
+    val feed: List<T> = items
+
+    fun updateAll(
+        selector: (List<T>) -> List<Int>,
+        transformer: (T) -> T,
+    ) {
+        selector(items).forEach {
+            safeUpdate(it, transformer)
+        }
+    }
+
+    fun safeUpdate(
+        index: Int,
+        transformer: (T) -> T,
+    ) {
+        if (!isValidIndex(index)) {
+            Log.d("FeedController", "OoB item not updated $index")
+            return
+        }
+
+        safeUpdate(index, transformer(items[index]))
+    }
+
+    fun safeUpdate(
+        selector: (List<T>) -> Int,
+        transformer: (T) -> T,
+    ) {
+        safeUpdate(selector(items), transformer)
+    }
+
+    /**
+     * Update the item at the given index with the new item.
+     *
+     * If given -1 or an index that is out of bounds, the update will not be performed.
+     * It assumes that the item couldn't be found because the list has changed.
+     * Example: a network request to update an item succeeded after the list has changed.
+     * So, we ignore it
+     */
+    fun safeUpdate(
+        index: Int,
+        new: T,
+    ) {
+        if (isValidIndex(index)) {
+            items[index] = new
+        } else {
+            Log.d("FeedController", "OoB item not updated $new")
+        }
+    }
+
+    fun add(item: T) = items.add(item)
+
+    fun remove(item: T) = items.remove(item)
+
+    fun clear() = items.clear()
+
+    fun addAll(newItems: List<T>) = items.addAll(newItems)
+
+    protected inline fun <E> Iterable<E>.indexesOf(predicate: (E) -> Boolean) =
+        mapIndexedNotNull { index, elem ->
+            index.takeIf {
+                predicate(elem)
+            }
+        }
+
+    private fun isValidIndex(index: Int) = index >= 0 && index < items.size
+}

app/src/main/java/com/jerboa/feed/PaginationController.kt

@@ -0,0 +1,18 @@
+package com.jerboa.feed
+
+import it.vercruysse.lemmyapi.v0x19.datatypes.PaginationCursor
+
+class PaginationController(
+    var page: Long = 1,
+    var pageCursor: PaginationCursor? = null,
+) {
+    fun reset() {
+        page = 1
+        pageCursor = null
+    }
+
+    fun nextPage(pageCursor: PaginationCursor?) {
+        page++
+        this.pageCursor = pageCursor
+    }
+}

app/src/main/java/com/jerboa/feed/PostController.kt

@@ -0,0 +1,42 @@
+package com.jerboa.feed
+
+import com.jerboa.datatypes.BanFromCommunityData
+import it.vercruysse.lemmyapi.v0x19.datatypes.HidePost
+import it.vercruysse.lemmyapi.v0x19.datatypes.Person
+import it.vercruysse.lemmyapi.v0x19.datatypes.PostView
+
+open class PostController : FeedController<PostView>() {
+    fun findAndUpdatePost(updatedPostView: PostView) {
+        safeUpdate({ posts ->
+            posts.indexOfFirst {
+                it.post.id == updatedPostView.post.id
+            }
+        }) { updatedPostView }
+    }
+
+    fun findAndUpdateCreator(person: Person) {
+        updateAll(
+            { it.indexesOf { postView -> postView.creator.id == person.id } },
+        ) { it.copy(creator = person) }
+    }
+
+    fun findAndUpdatePostCreatorBannedFromCommunity(banData: BanFromCommunityData) {
+        updateAll(
+            {
+                it.indexesOf { postView ->
+                    postView.creator.id == banData.person.id && postView.community.id == banData.community.id
+                }
+            },
+        ) { it.copy(banned_from_community = banData.banned, creator_banned_from_community = banData.banned, creator = banData.person) }
+    }
+
+    fun findAndUpdatePostHidden(hidePost: HidePost) {
+        updateAll(
+            {
+                it.indexesOf { postView ->
+                    hidePost.post_ids.contains(postView.post.id)
+                }
+            },
+        ) { it.copy(hidden = hidePost.hide) }
+    }
+}

app/src/main/java/com/jerboa/model/HomeViewModel.kt

@@ -1,14 +1,11 @@
 package com.jerboa.model
 
-import androidx.compose.foundation.lazy.LazyListState
 import androidx.lifecycle.viewmodel.initializer
 import androidx.lifecycle.viewmodel.viewModelFactory
 import com.jerboa.db.repository.AccountRepository
 import com.jerboa.jerboaApplication
 
 class HomeViewModel(accountRepository: AccountRepository) : PostsViewModel(accountRepository) {
-    val lazyListState = LazyListState()
-
     init {
         init()
     }

app/src/main/java/com/jerboa/model/PostViewModel.kt

@@ -48,8 +48,6 @@ import it.vercruysse.lemmyapi.v0x19.datatypes.SaveComment
 import it.vercruysse.lemmyapi.v0x19.datatypes.SavePost
 import kotlinx.coroutines.launch
 
-const val COMMENTS_DEPTH_MAX = 6L
-
 class PostViewModel(val id: Either<PostId, CommentId>) : ViewModel() {
     var postRes: ApiState<GetPostResponse> by mutableStateOf(ApiState.Empty)
         private set
@@ -442,5 +440,7 @@ class PostViewModel(val id: Either<PostId, CommentId>) : ViewModel() {
                 return PostViewModel(id) as T
             }
         }
+
+        const val COMMENTS_DEPTH_MAX = 6L
     }
 }