Cache related manga lists

app/src/main/kotlin/org/koitharu/kotatsu/core/cache/ContentCache.kt

@@ -16,8 +16,29 @@ interface ContentCache {
 
 	fun putPages(source: MangaSource, url: String, pages: SafeDeferred<List<MangaPage>>)
 
-	data class Key(
+	suspend fun getRelatedManga(source: MangaSource, url: String): List<Manga>?
+
+	fun putRelatedManga(source: MangaSource, url: String, related: SafeDeferred<List<Manga>>)
+
+	class Key(
 		val source: MangaSource,
 		val url: String,
-	)
+	) {
+
+		override fun equals(other: Any?): Boolean {
+			if (this === other) return true
+			if (javaClass != other?.javaClass) return false
+
+			other as Key
+
+			if (source != other.source) return false
+			return url == other.url
+		}
+
+		override fun hashCode(): Int {
+			var result = source.hashCode()
+			result = 31 * result + url.hashCode()
+			return result
+		}
+	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/core/cache/MemoryContentCache.kt

@@ -16,6 +16,7 @@ class MemoryContentCache(application: Application) : ContentCache, ComponentCall
 
 	private val detailsCache = ExpiringLruCache<SafeDeferred<Manga>>(4, 5, TimeUnit.MINUTES)
 	private val pagesCache = ExpiringLruCache<SafeDeferred<List<MangaPage>>>(4, 10, TimeUnit.MINUTES)
+	private val relatedMangaCache = ExpiringLruCache<SafeDeferred<List<Manga>>>(4, 10, TimeUnit.MINUTES)
 
 	override val isCachingEnabled: Boolean = true
 
@@ -35,6 +36,14 @@ class MemoryContentCache(application: Application) : ContentCache, ComponentCall
 		pagesCache[ContentCache.Key(source, url)] = pages
 	}
 
+	override suspend fun getRelatedManga(source: MangaSource, url: String): List<Manga>? {
+		return relatedMangaCache[ContentCache.Key(source, url)]?.awaitOrNull()
+	}
+
+	override fun putRelatedManga(source: MangaSource, url: String, related: SafeDeferred<List<Manga>>) {
+		relatedMangaCache[ContentCache.Key(source, url)] = related
+	}
+
 	override fun onConfigurationChanged(newConfig: Configuration) = Unit
 
 	override fun onLowMemory() = Unit
@@ -42,6 +51,7 @@ class MemoryContentCache(application: Application) : ContentCache, ComponentCall
 	override fun onTrimMemory(level: Int) {
 		trimCache(detailsCache, level)
 		trimCache(pagesCache, level)
+		trimCache(relatedMangaCache, level)
 	}
 
 	private fun trimCache(cache: ExpiringLruCache<*>, level: Int) {

app/src/main/kotlin/org/koitharu/kotatsu/core/cache/StubContentCache.kt

@@ -15,4 +15,8 @@ class StubContentCache : ContentCache {
 	override suspend fun getPages(source: MangaSource, url: String): List<MangaPage>? = null
 
 	override fun putPages(source: MangaSource, url: String, pages: SafeDeferred<List<MangaPage>>) = Unit
+
+	override suspend fun getRelatedManga(source: MangaSource, url: String): List<Manga>? = null
+
+	override fun putRelatedManga(source: MangaSource, url: String, related: SafeDeferred<List<Manga>>) = Unit
 }

app/src/main/kotlin/org/koitharu/kotatsu/core/parser/RemoteMangaRepository.kt

@@ -95,7 +95,12 @@ class RemoteMangaRepository(
 	suspend fun getFavicons(): Favicons = parser.getFavicons()
 
 	override suspend fun getRelated(seed: Manga): List<Manga> {
-		return parser.getRelatedManga(seed).filterNot { it.id == seed.id }
+		cache.getRelatedManga(source, seed.url)?.let { return it }
+		val related = asyncSafe {
+			parser.getRelatedManga(seed).filterNot { it.id == seed.id }
+		}
+		cache.putRelatedManga(source, seed.url, related)
+		return related.await()
 	}
 
 	fun getAuthProvider(): MangaParserAuthProvider? = parser as? MangaParserAuthProvider