Clean up ChapterCache (remove Gson, Rx usage)

(cherry picked from commit 356b7c346aba9dd0fafbb089c56de11ac50d1065)

# Conflicts:
#	app/src/main/java/eu/kanade/tachiyomi/data/cache/ChapterCache.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt

app/src/main/java/eu/kanade/tachiyomi/data/cache/ChapterCache.kt

@@ -2,8 +2,6 @@ package eu.kanade.tachiyomi.data.cache
 
 import android.content.Context
 import android.text.format.Formatter
-import com.github.salomonbrys.kotson.fromJson
-import com.google.gson.Gson
 import com.jakewharton.disklrucache.DiskLruCache
 import eu.kanade.tachiyomi.data.database.models.Chapter
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
@@ -15,10 +13,12 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
+import kotlinx.serialization.decodeFromString
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
 import okhttp3.Response
 import okio.buffer
 import okio.sink
-import rx.Observable
 import uy.kohesive.injekt.injectLazy
 import java.io.File
 import java.io.IOException
@@ -48,14 +48,12 @@ class ChapterCache(private val context: Context) {
     private val scope = CoroutineScope(Job() + Dispatchers.Main)
 
     /** Google Json class used for parsing JSON files.  */
-    private val gson: Gson by injectLazy()
+    private val json: Json by injectLazy()
 
     // --> EH
     private val prefs: PreferencesHelper by injectLazy()
-    // <-- EH
 
     /** Cache class used for cache management.  */
-    // --> EH
     private var diskCache = setupDiskCache(prefs.cacheSize().get().toLong())
 
     init {
@@ -73,7 +71,7 @@ class ChapterCache(private val context: Context) {
     /**
      * Returns directory of cache.
      */
-    val cacheDir: File
+    private val cacheDir: File
         get() = diskCache.directory
 
     /**
@@ -100,43 +98,19 @@ class ChapterCache(private val context: Context) {
     }
     // <-- EH
 
-    /**
-     * Remove file from cache.
-     *
-     * @param file name of file "md5.0".
-     * @return status of deletion for the file.
-     */
-    fun removeFileFromCache(file: String): Boolean {
-        // Make sure we don't delete the journal file (keeps track of cache).
-        if (file == "journal" || file.startsWith("journal.")) {
-            return false
-        }
-
-        return try {
-            // Remove the extension from the file to get the key of the cache
-            val key = file.substringBeforeLast(".")
-            // Remove file from cache.
-            diskCache.remove(key)
-        } catch (e: Exception) {
-            false
-        }
-    }
-
     /**
      * Get page list from cache.
      *
      * @param chapter the chapter.
-     * @return an observable of the list of pages.
+     * @return the list of pages.
      */
-    fun getPageListFromCache(chapter: Chapter): Observable<List<Page>> {
+    fun getPageListFromCache(chapter: Chapter): List<Page> {
-        return Observable.fromCallable {
         // Get the key for the chapter.
         val key = DiskUtil.hashKeyForDisk(getKey(chapter))
 
         // Convert JSON string to list of objects. Throws an exception if snapshot is null
-            diskCache.get(key).use {
+        return diskCache.get(key).use {
-                gson.fromJson<List<Page>>(it.getString(0))
+            json.decodeFromString(it.getString(0))
-            }
         }
     }
 
@@ -148,7 +122,7 @@ class ChapterCache(private val context: Context) {
      */
     fun putPageListToCache(chapter: Chapter, pages: List<Page>) {
         // Convert list of pages to json string.
-        val cachedValue = gson.toJson(pages)
+        val cachedValue = json.encodeToString(pages)
 
         // Initialize the editor (edits the values for an entry).
         var editor: DiskLruCache.Editor? = null
@@ -228,6 +202,38 @@ class ChapterCache(private val context: Context) {
         }
     }
 
+    fun clear(): Int {
+        var deletedFiles = 0
+        cacheDir.listFiles()?.forEach {
+            if (removeFileFromCache(it.name)) {
+                deletedFiles++
+            }
+        }
+        return deletedFiles
+    }
+
+    /**
+     * Remove file from cache.
+     *
+     * @param file name of file "md5.0".
+     * @return status of deletion for the file.
+     */
+    private fun removeFileFromCache(file: String): Boolean {
+        // Make sure we don't delete the journal file (keeps track of cache).
+        if (file == "journal" || file.startsWith("journal.")) {
+            return false
+        }
+
+        return try {
+            // Remove the extension from the file to get the key of the cache
+            val key = file.substringBeforeLast(".")
+            // Remove file from cache.
+            diskCache.remove(key)
+        } catch (e: Exception) {
+            false
+        }
+    }
+
     private fun getKey(chapter: Chapter): String {
         return "${chapter.manga_id}${chapter.url}"
     }

app/src/main/java/eu/kanade/tachiyomi/ui/reader/loader/HttpPageLoader.kt

@@ -99,8 +99,7 @@ class HttpPageLoader(
      * the local cache, otherwise fallbacks to network.
      */
     override fun getPages(): Observable<List<ReaderPage>> {
-        return chapterCache
+        return Observable.fromCallable { chapterCache.getPageListFromCache(chapter.chapter) }
-            .getPageListFromCache(chapter.chapter)
             .onErrorResumeNext { source.fetchPageList(chapter.chapter) }
             .map { pages ->
                 // SY -->

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt

@@ -29,7 +29,8 @@ import eu.kanade.tachiyomi.source.SourceManager.Companion.DELEGATED_SOURCES
 import eu.kanade.tachiyomi.ui.base.controller.DialogController
 import eu.kanade.tachiyomi.ui.base.controller.withFadeTransaction
 import eu.kanade.tachiyomi.util.CrashLogUtil
-import eu.kanade.tachiyomi.util.lang.launchUI
+import eu.kanade.tachiyomi.util.lang.launchIO
+import eu.kanade.tachiyomi.util.lang.withUIContext
 import eu.kanade.tachiyomi.util.preference.defaultValue
 import eu.kanade.tachiyomi.util.preference.editTextPreference
 import eu.kanade.tachiyomi.util.preference.intListPreference
@@ -53,9 +54,6 @@ import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.launch
-import rx.Observable
-import rx.android.schedulers.AndroidSchedulers
-import rx.schedulers.Schedulers
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
 import uy.kohesive.injekt.injectLazy
@@ -372,8 +370,8 @@ class SettingsAdvancedController : SettingsController() {
                     foldersCleared += downloadManager.cleanupChapters(chapterList, manga, source, removeRead, removeNonFavorite)
                 }
             }
-            launchUI {
+            withUIContext {
-                val activity = activity ?: return@launchUI
+                val activity = activity ?: return@withUIContext
                 val cleanupString =
                     if (foldersCleared == 0) activity.getString(R.string.no_folders_to_cleanup)
                     else resources!!.getQuantityString(
@@ -389,27 +387,18 @@ class SettingsAdvancedController : SettingsController() {
 
     private fun clearChapterCache() {
         if (activity == null) return
-        val files = chapterCache.cacheDir.listFiles() ?: return
+        launchIO {
-
+            try {
-        var deletedFiles = 0
+                val deletedFiles = chapterCache.clear()
-
+                withUIContext {
-        Observable.defer { Observable.from(files) }
-            .doOnNext { file ->
-                if (chapterCache.removeFileFromCache(file.name)) {
-                    deletedFiles++
-                }
-            }
-            .subscribeOn(Schedulers.io())
-            .observeOn(AndroidSchedulers.mainThread())
-            .doOnError {
-                activity?.toast(R.string.cache_delete_error)
-            }
-            .doOnCompleted {
                     activity?.toast(resources?.getString(R.string.cache_deleted, deletedFiles))
                     findPreference(CLEAR_CACHE_KEY)?.summary =
                         resources?.getString(R.string.used_cache, chapterCache.readableSize)
                 }
-            .subscribe()
+            } catch (e: Throwable) {
+                withUIContext { activity?.toast(R.string.cache_delete_error) }
+            }
+        }
     }
 
     class ClearDatabaseDialogController : DialogController() {