Limit lifetime of memory content cache

app/src/main/java/org/koitharu/kotatsu/core/cache/DeferredLruCache.kt

@@ -1,5 +0,0 @@
-package org.koitharu.kotatsu.core.cache
-
-import androidx.collection.LruCache
-
-class DeferredLruCache<T>(maxSize: Int) : LruCache<ContentCache.Key, SafeDeferred<T>>(maxSize)

app/src/main/java/org/koitharu/kotatsu/core/cache/ExpiringLruCache.kt

@@ -0,0 +1,33 @@
+package org.koitharu.kotatsu.core.cache
+
+import androidx.collection.LruCache
+import java.util.concurrent.TimeUnit
+
+class ExpiringLruCache<T>(
+	val maxSize: Int,
+	private val lifetime: Long,
+	private val timeUnit: TimeUnit,
+) {
+
+	private val cache = LruCache<ContentCache.Key, ExpiringValue<T>>(maxSize)
+
+	operator fun get(key: ContentCache.Key): T? {
+		val value = cache.get(key) ?: return null
+		if (value.isExpired) {
+			cache.remove(key)
+		}
+		return value.get()
+	}
+
+	operator fun set(key: ContentCache.Key, value: T) {
+		cache.put(key, ExpiringValue(value, lifetime, timeUnit))
+	}
+
+	fun clear() {
+		cache.evictAll()
+	}
+
+	fun trimToSize(size: Int) {
+		cache.trimToSize(size)
+	}
+}

app/src/main/java/org/koitharu/kotatsu/core/cache/ExpiringValue.kt

@@ -0,0 +1,34 @@
+package org.koitharu.kotatsu.core.cache
+
+import android.os.SystemClock
+import java.util.concurrent.TimeUnit
+
+class ExpiringValue<T>(
+	private val value: T,
+	lifetime: Long,
+	timeUnit: TimeUnit,
+) {
+
+	private val expiresAt = SystemClock.elapsedRealtime() + timeUnit.toMillis(lifetime)
+
+	val isExpired: Boolean
+		get() = SystemClock.elapsedRealtime() >= expiresAt
+
+	fun get(): T? = if (isExpired) null else value
+
+	override fun equals(other: Any?): Boolean {
+		if (this === other) return true
+		if (javaClass != other?.javaClass) return false
+
+		other as ExpiringValue<*>
+
+		if (value != other.value) return false
+		return expiresAt == other.expiresAt
+	}
+
+	override fun hashCode(): Int {
+		var result = value?.hashCode() ?: 0
+		result = 31 * result + expiresAt.hashCode()
+		return result
+	}
+}

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

@@ -6,6 +6,7 @@ import android.content.res.Configuration
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaPage
 import org.koitharu.kotatsu.parsers.model.MangaSource
+import java.util.concurrent.TimeUnit
 
 class MemoryContentCache(application: Application) : ContentCache, ComponentCallbacks2 {
 
@@ -13,8 +14,8 @@ class MemoryContentCache(application: Application) : ContentCache, ComponentCall
 		application.registerComponentCallbacks(this)
 	}
 
-	private val detailsCache = DeferredLruCache<Manga>(4)
+	private val detailsCache = ExpiringLruCache<SafeDeferred<Manga>>(4, 5, TimeUnit.MINUTES)
-	private val pagesCache = DeferredLruCache<List<MangaPage>>(4)
+	private val pagesCache = ExpiringLruCache<SafeDeferred<List<MangaPage>>>(4, 10, TimeUnit.MINUTES)
 
 	override val isCachingEnabled: Boolean = true
 
@@ -23,7 +24,7 @@ class MemoryContentCache(application: Application) : ContentCache, ComponentCall
 	}
 
 	override fun putDetails(source: MangaSource, url: String, details: SafeDeferred<Manga>) {
-		detailsCache.put(ContentCache.Key(source, url), details)
+		detailsCache[ContentCache.Key(source, url)] = details
 	}
 
 	override suspend fun getPages(source: MangaSource, url: String): List<MangaPage>? {
@@ -31,7 +32,7 @@ class MemoryContentCache(application: Application) : ContentCache, ComponentCall
 	}
 
 	override fun putPages(source: MangaSource, url: String, pages: SafeDeferred<List<MangaPage>>) {
-		pagesCache.put(ContentCache.Key(source, url), pages)
+		pagesCache[ContentCache.Key(source, url)] = pages
 	}
 
 	override fun onConfigurationChanged(newConfig: Configuration) = Unit
@@ -43,17 +44,17 @@ class MemoryContentCache(application: Application) : ContentCache, ComponentCall
 		trimCache(pagesCache, level)
 	}
 
-	private fun trimCache(cache: DeferredLruCache<*>, level: Int) {
+	private fun trimCache(cache: ExpiringLruCache<*>, level: Int) {
 		when (level) {
 			ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL,
 			ComponentCallbacks2.TRIM_MEMORY_COMPLETE,
-			ComponentCallbacks2.TRIM_MEMORY_MODERATE -> cache.evictAll()
+			ComponentCallbacks2.TRIM_MEMORY_MODERATE -> cache.clear()
 
 			ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN,
 			ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW,
 			ComponentCallbacks2.TRIM_MEMORY_BACKGROUND -> cache.trimToSize(1)
 
-			else -> cache.trimToSize(cache.maxSize() / 2)
+			else -> cache.trimToSize(cache.maxSize / 2)
 		}
 	}
 }