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src: add an in-memory map to cache db posts

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Signed-off-by: Aditya Wasan <adityawasan55@gmail.com>
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Aditya Wasan 2021-01-31 15:42:39 +05:30
parent d4ecf97436
commit a2c058877a
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3 changed files with 39 additions and 29 deletions
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45
app/src/main/java/dev/msfjarvis/lobsters/data/repo/LobstersRepository.kt
View file

@ -2,35 +2,56 @@ package dev.msfjarvis.lobsters.data.repo
import dev.msfjarvis.lobsters.data.local.LobstersPost
import dev.msfjarvis.lobsters.database.LobstersDatabase
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import javax.inject.Inject
class LobstersRepository @Inject constructor(private val lobstersDatabase: LobstersDatabase) {
private val savedPostsCache: MutableMap<String, LobstersPost> = mutableMapOf()
private val coroutineScope = CoroutineScope(Job() + Dispatchers.IO)
init {
coroutineScope.launch {
getAllPosts().forEach {
savedPostsCache.putIfAbsent(it.short_id, it)
}
}
}
fun isPostSaved(postId: String): Boolean {
val post = lobstersDatabase.postQueries.isPostSaved(postId).executeAsOneOrNull()
return post != null
return savedPostsCache.containsKey(postId)
}
suspend fun getPost(postId: String): LobstersPost? = withContext(Dispatchers.IO) {
fun getPostFromCache(postId: String): LobstersPost? {
return savedPostsCache[postId]
}
fun getAllPostsFromCache(): List<LobstersPost> {
return savedPostsCache.values.toList()
}
private suspend fun getPost(postId: String): LobstersPost? = withContext(Dispatchers.IO) {
return@withContext lobstersDatabase.postQueries.selectPost(postId).executeAsOneOrNull()
}
suspend fun getSavedPosts(): List<LobstersPost> = withContext(Dispatchers.IO) {
return@withContext lobstersDatabase.postQueries.selectSavedPosts().executeAsList()
private suspend fun getAllPosts(): List<LobstersPost> = withContext(Dispatchers.IO) {
return@withContext lobstersDatabase.postQueries.selectAllPosts().executeAsList()
}
suspend fun addPostToDB(post: LobstersPost) = withContext(Dispatchers.IO) {
lobstersDatabase.postQueries.insertOrReplacePost(post)
}
suspend fun savePost(post: LobstersPost) = withContext(Dispatchers.IO) {
suspend fun addPost(post: LobstersPost) = withContext(Dispatchers.IO) {
if (!savedPostsCache.containsKey(post.short_id)) {
savedPostsCache.putIfAbsent(post.short_id, post)
lobstersDatabase.postQueries.insertOrReplacePost(post.copy(is_saved = true))
}
}
suspend fun removeSavedPost(post: LobstersPost) = withContext(Dispatchers.IO) {
if (isPostSaved(post.short_id)) {
suspend fun removePost(post: LobstersPost) = withContext(Dispatchers.IO) {
if (savedPostsCache.containsKey(post.short_id)) {
savedPostsCache.remove(post.short_id)
lobstersDatabase.postQueries.removeSavedPost(post.short_id)
}
}

2
app/src/main/java/dev/msfjarvis/lobsters/ui/main/MainActivity.kt
View file

@ -64,8 +64,6 @@ fun LobstersApp() {
val savedPosts by viewModel.savedPosts.collectAsState()
val hottestPostsListState = rememberLazyListState()
viewModel.getSavedPosts()
Scaffold(
bottomBar = {
LobstersBottomNav(

21
app/src/main/java/dev/msfjarvis/lobsters/ui/viewmodel/LobstersViewModel.kt
View file

@ -17,12 +17,11 @@ import javax.inject.Inject
@HiltViewModel
class LobstersViewModel @Inject constructor(
private val pagingSource: LobstersPagingSource,
private val lobstersRepository: LobstersRepository,
private val lobstersApi: LobstersApi,
) : ViewModel() {
private val _savedPosts = MutableStateFlow<List<LobstersPost>>(emptyList())
private lateinit var source: LobstersPagingSource
private val _savedPosts = MutableStateFlow(lobstersRepository.getAllPostsFromCache())
val savedPosts = _savedPosts.asStateFlow()
val posts = Pager(PagingConfig(25)) {
source = LobstersPagingSource(lobstersApi, lobstersRepository)
@ -37,29 +36,21 @@ class LobstersViewModel @Inject constructor(
}
}
fun getSavedPosts() {
viewModelScope.launch {
lobstersRepository.getSavedPosts().forEach {
_savedPosts.value = _savedPosts.value + it
}
}
}
fun invalidateSource() {
private fun invalidateSource() {
source.invalidate()
}
private fun savePost(post: LobstersPost) {
viewModelScope.launch {
lobstersRepository.savePost(post)
_savedPosts.value = _savedPosts.value + post.copy(is_saved = true)
lobstersRepository.addPost(post)
_savedPosts.value = lobstersRepository.getAllPostsFromCache()
}
}
private fun removeSavedPost(post: LobstersPost) {
viewModelScope.launch {
lobstersRepository.removeSavedPost(post)
_savedPosts.value = _savedPosts.value - post.copy(is_saved = true)
lobstersRepository.removePost(post)
_savedPosts.value = lobstersRepository.getAllPostsFromCache()
}
}
}