Clean obsolete cache on start

app/src/main/java/com/hippo/ehviewer/EhApplication.kt

@@ -53,6 +53,7 @@ import io.ktor.client.plugins.cookies.HttpCookies
 import kotlinx.coroutines.DelicateCoroutinesApi
 import okhttp3.OkHttpClient
 import okio.Path.Companion.toOkioPath
+import java.io.File
 import java.net.InetAddress
 import java.net.InetSocketAddress
 import java.net.Proxy
@@ -77,7 +78,6 @@ class EhApplication : Application(), DefaultLifecycleObserver, ImageLoaderFactor
     }
 
     @OptIn(DelicateCoroutinesApi::class)
-    @SuppressLint("StaticFieldLeak")
     override fun onCreate() {
         ProcessLifecycleOwner.get().lifecycle.addObserver(this)
         application = this
@@ -114,10 +114,24 @@ class EhApplication : Application(), DefaultLifecycleObserver, ImageLoaderFactor
                     checkDawn()
                 }
             }
+            launchIO {
+                cleanObsoleteCache()
+            }
         }
         mIdGenerator.setNextId(Settings.getInt(KEY_GLOBAL_STUFF_NEXT_ID, 0))
     }
 
+    // TODO: Remove this after a few releases
+    private fun cleanObsoleteCache() {
+        val dir = cacheDir
+        for (subdir in OBSOLETE_CACHE_DIRS) {
+            val file = File(dir, subdir)
+            if (file.exists()) {
+                file.deleteRecursively()
+            }
+        }
+    }
+
     private fun cleanupDownload() {
         try {
             val downloadLocation = Settings.downloadLocation
@@ -210,6 +224,15 @@ class EhApplication : Application(), DefaultLifecycleObserver, ImageLoaderFactor
         var locked = true
         var locked_last_leave_time: Long = 0
 
+        private val OBSOLETE_CACHE_DIRS = arrayOf(
+            "image",
+            "thumb",
+            "http_cache",
+            "image_cache",
+            "gallery_image",
+            "spider_info"
+        )
+
         @JvmStatic
         lateinit var application: EhApplication
             private set