diff --git a/app/src/main/kotlin/com/hippo/ehviewer/coil/DownloadThumbInterceptor.kt b/app/src/main/kotlin/com/hippo/ehviewer/coil/DownloadThumbInterceptor.kt
index ba564f725..3fb87432a 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/coil/DownloadThumbInterceptor.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/coil/DownloadThumbInterceptor.kt
@@ -11,37 +11,29 @@ import com.hippo.unifile.asUniFile
 import eu.kanade.tachiyomi.util.lang.withIOContext
 
 object DownloadThumbInterceptor : Interceptor {
-    // TODO: Remove this after a few releases
-    private const val LEGACY_THUMB_FILE = ".thumb"
     private const val THUMB_FILE = "thumb.jpg"
     override suspend fun intercept(chain: Interceptor.Chain): ImageResult {
         val magicOrUrl = chain.request.data as? String
         if (magicOrUrl != null) {
             val (url, location) = decodeMagicRequestOrUrl(magicOrUrl)
             if (location != null) {
-                val thumb = withIOContext {
-                    val legacyThumb = downloadLocation / location / LEGACY_THUMB_FILE
-                    if (legacyThumb.isFile) {
-                        legacyThumb.apply { renameTo(THUMB_FILE) }
-                    } else {
-                        downloadLocation / location / THUMB_FILE
-                    }
-                }
-                if (withIOContext { thumb.isFile }) {
-                    val new = chain.request.newBuilder().data(thumb.uri.toString()).build()
+                val downloadDir = withIOContext { downloadLocation.findFile(location) }
+                val thumb = withIOContext { downloadDir?.findFile(THUMB_FILE) }
+                thumb?.run {
+                    val new = chain.request.newBuilder().data(uri).build()
                     val result = chain.withRequest(new).proceed()
                     if (result is SuccessResult) return result
                 }
                 val new = chain.request.newBuilder().data(url).build()
                 val result = chain.withRequest(new).proceed()
-                if (result is SuccessResult) {
+                if (result is SuccessResult && downloadDir != null) {
                     withIOContext {
                         // Accessing the recreated file immediately after deleting it throws
                         // FileNotFoundException, so we just overwrite the existing file.
-                        if (thumb.ensureFile()) {
+                        (thumb ?: downloadDir.createFile(THUMB_FILE))?.let {
                             val key = requireNotNull(chain.request.memoryCacheKey)
                             imageCache.read(key) {
-                                data.asUniFile() sendTo thumb
+                                data.asUniFile() sendTo it
                             }
                         }
                     }
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/download/DownloadManager.kt b/app/src/main/kotlin/com/hippo/ehviewer/download/DownloadManager.kt
index dad53d2db..648ce0652 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/download/DownloadManager.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/download/DownloadManager.kt
@@ -813,17 +813,16 @@ object DownloadManager : OnSpiderListener, CoroutineScope {
     private fun comparator() = SortMode.from(Settings.downloadSortMode.value).comparator()
 }
 
-var downloadLocation: UniFile
-    get() = with(Settings) {
-        val uri = Uri.Builder().apply {
-            scheme(downloadScheme)
-            encodedAuthority(downloadAuthority)
-            encodedPath(downloadPath)
-            encodedQuery(downloadQuery)
-            encodedFragment(downloadFragment)
-        }.build()
-        uri.asUniFileOrNull() ?: AppConfig.defaultDownloadDir?.asUniFile() ?: UniFile.Stub
-    }
+var downloadLocation = with(Settings) {
+    val uri = Uri.Builder().apply {
+        scheme(downloadScheme)
+        encodedAuthority(downloadAuthority)
+        encodedPath(downloadPath)
+        encodedQuery(downloadQuery)
+        encodedFragment(downloadFragment)
+    }.build()
+    uri.asUniFileOrNull() ?: AppConfig.defaultDownloadDir?.asUniFile() ?: UniFile.Stub
+}
     set(value) = with(value.uri) {
         Settings.edit {
             downloadScheme = scheme
@@ -832,8 +831,9 @@ var downloadLocation: UniFile
             downloadQuery = encodedQuery
             downloadFragment = encodedFragment
         }
+        field = value
     }
 
-val DownloadInfo.downloadDir get() = dirname?.let { downloadLocation / it }
+val DownloadInfo.downloadDir get() = dirname?.let { downloadLocation.findFile(it) }
 val DownloadInfo.archiveFile get() = downloadDir?.run { findFile("$gid.cbz") ?: findFile("$gid.zip") }
-val GalleryInfo.tempDownloadDir get() = AppConfig.getTempDir("$gid")
+val GalleryInfo.tempDownloadDir get() = AppConfig.getTempDir("$gid")?.asUniFile()
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/gallery/PageLoader2.kt b/app/src/main/kotlin/com/hippo/ehviewer/gallery/PageLoader2.kt
index cdda13c53..181af9e8d 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/gallery/PageLoader2.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/gallery/PageLoader2.kt
@@ -69,8 +69,4 @@ abstract class PageLoader2(private val gid: Long, var startPage: Int) :
     }
 
     abstract fun save(index: Int, file: UniFile): Boolean
-
-    fun saveToDir(index: Int, dir: UniFile): UniFile? = getImageFilename(index)?.let { filename ->
-        (dir / filename).takeIf { save(index, it) }
-    }
 }
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/spider/SpiderDen.kt b/app/src/main/kotlin/com/hippo/ehviewer/spider/SpiderDen.kt
index a522ca8da..52dc1bacd 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/spider/SpiderDen.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/spider/SpiderDen.kt
@@ -42,7 +42,6 @@ import com.hippo.ehviewer.util.FileUtils
 import com.hippo.ehviewer.util.sendTo
 import com.hippo.unifile.UniFile
 import com.hippo.unifile.asUniFile
-import com.hippo.unifile.ensureDirOrThrow
 import com.hippo.unifile.openOutputStream
 import com.hippo.unifile.sha1
 import eu.kanade.tachiyomi.util.system.logcat
@@ -68,7 +67,7 @@ class SpiderDen(val info: GalleryInfo) {
         get() = tempDownloadDir.takeIf { saveAsCbz } ?: downloadDir
 
     constructor(info: GalleryInfo, dirname: String) : this(info) {
-        downloadDir = downloadLocation / dirname
+        downloadDir = downloadLocation.findFile(dirname)
     }
 
     @Volatile
@@ -80,10 +79,11 @@ class SpiderDen(val info: GalleryInfo) {
         mode = value
         if (mode == SpiderQueen.MODE_DOWNLOAD) {
             if (downloadDir == null) {
-                downloadDir = getGalleryDownloadDir(gid)!!.apply { ensureDirOrThrow() }
+                val dirname = EhDB.getDownloadDirname(gid)!!
+                downloadDir = downloadLocation.createDirectory(dirname)!!
             }
             if (saveAsCbz && tempDownloadDir == null) {
-                tempDownloadDir = info.tempDownloadDir!!.apply { ensureDirOrThrow() }
+                tempDownloadDir = info.tempDownloadDir!!
             }
         }
     }
@@ -283,10 +283,8 @@ class SpiderDen(val info: GalleryInfo) {
 
     private suspend fun archiveTo(file: UniFile) = resourceScope {
         val comicInfo = closeable {
-            val f = downloadDir!! / COMIC_INFO_FILE
-            if (!f.exists()) {
-                writeComicInfo()
-            } else if (info.pages == 0) {
+            val f = downloadDir!!.findFile(COMIC_INFO_FILE) ?: writeComicInfo()!!
+            if (info.pages == 0) {
                 info.pages = readComicInfo(f)!!.pageCount
             }
             f.openFileDescriptor("r")
@@ -301,32 +299,30 @@ class SpiderDen(val info: GalleryInfo) {
     }
 
     suspend fun initDownloadDirIfExist() {
-        downloadDir = getGalleryDownloadDir(gid)?.takeIf { it.isDirectory }
+        downloadDir = EhDB.getDownloadDirname(gid)?.let { downloadLocation.findFile(it) }
         tempDownloadDir = info.tempDownloadDir?.takeIf { it.isDirectory }
     }
 
     suspend fun initDownloadDir() {
-        downloadDir = getGalleryDownloadDir(gid) ?: (downloadLocation / info.putToDownloadDir())
-        downloadDir!!.ensureDirOrThrow()
+        val dirname = EhDB.getDownloadDirname(gid) ?: info.putToDownloadDir()
+        downloadDir = downloadLocation.createDirectory(dirname)!!
     }
 
-    suspend fun writeComicInfo(fetchMetadata: Boolean = true) {
-        downloadDir?.run {
-            createFile(COMIC_INFO_FILE)?.also {
-                runCatching {
-                    if (info !is GalleryDetail && fetchMetadata) {
-                        EhEngine.fillGalleryListByApi(listOf(info))
-                    }
-                    info.getComicInfo().apply {
-                        write(it)
-                        DownloadManager.getDownloadInfo(gid)?.let { downloadInfo ->
-                            downloadInfo.artistInfoList = DownloadArtist.from(gid, penciller.orEmpty())
-                            EhDB.putDownloadArtist(gid, downloadInfo.artistInfoList)
-                        }
-                    }
-                }.onFailure {
-                    logcat(it)
+    suspend fun writeComicInfo(fetchMetadata: Boolean = true): UniFile? = downloadDir?.run {
+        createFile(COMIC_INFO_FILE)?.also {
+            runCatching {
+                if (info !is GalleryDetail && fetchMetadata) {
+                    EhEngine.fillGalleryListByApi(listOf(info))
                 }
+                info.getComicInfo().apply {
+                    write(it)
+                    DownloadManager.getDownloadInfo(gid)?.let { downloadInfo ->
+                        downloadInfo.artistInfoList = DownloadArtist.from(gid, penciller.orEmpty())
+                        EhDB.putDownloadArtist(gid, downloadInfo.artistInfoList)
+                    }
+                }
+            }.onFailure {
+                logcat(it)
             }
         }
     }
@@ -348,8 +344,3 @@ suspend fun GalleryInfo.putToDownloadDir(): String {
     EhDB.putDownloadDirname(gid, dirname)
     return dirname
 }
-
-suspend fun getGalleryDownloadDir(gid: Long): UniFile? {
-    val dirname = EhDB.getDownloadDirname(gid) ?: return null
-    return downloadLocation / dirname
-}
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/ui/CommonOperations.kt b/app/src/main/kotlin/com/hippo/ehviewer/ui/CommonOperations.kt
index 32c6b1297..54969acac 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/ui/CommonOperations.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/ui/CommonOperations.kt
@@ -80,8 +80,7 @@ import moe.tarsin.coroutines.runSuspendCatching
 import splitties.init.appCtx
 
 private fun removeNoMediaFile(downloadDir: UniFile) {
-    val noMedia = downloadDir / ".nomedia"
-    noMedia.delete()
+    downloadDir.findFile(".nomedia")?.delete()
 }
 
 private fun ensureNoMediaFile(downloadDir: UniFile) {
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/ui/MainActivity.kt b/app/src/main/kotlin/com/hippo/ehviewer/ui/MainActivity.kt
index 80eb3cdd3..261c3b04b 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/ui/MainActivity.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/ui/MainActivity.kt
@@ -227,7 +227,7 @@ class MainActivity : EhActivity() {
             }
 
             suspend fun DialogState.checkDownloadLocation() {
-                val valid = withIOContext { downloadLocation.ensureDir() }
+                val valid = withIOContext { downloadLocation.isDirectory }
                 if (!valid) {
                     awaitPermissionOrCancel(
                         confirmText = R.string.open_settings,
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/PageActions.kt b/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/PageActions.kt
index f11f2dfb1..53113d719 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/PageActions.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/ui/reader/PageActions.kt
@@ -35,8 +35,9 @@ import splitties.systemservices.clipboardManager
 context(PageLoader2)
 private fun Context.provideImage(index: Int): Uri? {
     val dir = AppConfig.externalTempDir ?: return null
-    val name = saveToDir(index, dir.asUniFile())?.name ?: return null
-    return FileProvider.getUriForFile(this, "$APPLICATION_ID.fileprovider", File(dir, name))
+    val name = getImageFilename(index) ?: return null
+    val file = File(dir, name).takeIf { save(index, it.asUniFile()) } ?: return null
+    return FileProvider.getUriForFile(this, "$APPLICATION_ID.fileprovider", file)
 }
 
 context(SnackbarHostState, Context, PageLoader2)
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/ui/settings/AdvancedScreen.kt b/app/src/main/kotlin/com/hippo/ehviewer/ui/settings/AdvancedScreen.kt
index 403b14f32..f3683d5f9 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/ui/settings/AdvancedScreen.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/ui/settings/AdvancedScreen.kt
@@ -50,6 +50,7 @@ import com.hippo.ehviewer.util.isAtLeastO
 import com.hippo.ehviewer.util.isAtLeastV
 import com.hippo.ehviewer.util.setAppLanguage
 import com.hippo.unifile.asUniFile
+import com.hippo.unifile.displayPath
 import com.jamal.composeprefs3.ui.prefs.DropDownPref
 import com.jamal.composeprefs3.ui.prefs.SwitchPref
 import com.ramcosta.composedestinations.annotation.Destination
@@ -130,7 +131,7 @@ fun AdvancedScreen(navigator: DestinationsNavigator) {
                                 Crash.collectInfo(zipOs.writer())
                                 Runtime.getRuntime().exec("logcat -d").inputStream.use { it.copyTo(zipOs) }
                             }
-                            launchSnackBar(getString(R.string.settings_advanced_dump_logcat_to, uri.toString()))
+                            launchSnackBar(getString(R.string.settings_advanced_dump_logcat_to, uri.displayPath))
                         }
                     }.onFailure {
                         launchSnackBar(dumpLogError)
@@ -201,7 +202,7 @@ fun AdvancedScreen(navigator: DestinationsNavigator) {
                     context.runCatching {
                         grantUriPermission(BuildConfig.APPLICATION_ID, uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION)
                         EhDB.exportDB(context, uri.asUniFile())
-                        launchSnackBar(getString(R.string.settings_advanced_export_data_to, uri.toString()))
+                        launchSnackBar(getString(R.string.settings_advanced_export_data_to, uri.displayPath))
                     }.onFailure {
                         logcat(it)
                         launchSnackBar(exportFailed)
diff --git a/app/src/main/kotlin/com/hippo/ehviewer/util/AppConfig.kt b/app/src/main/kotlin/com/hippo/ehviewer/util/AppConfig.kt
index 9e8c9430a..85b983d5f 100644
--- a/app/src/main/kotlin/com/hippo/ehviewer/util/AppConfig.kt
+++ b/app/src/main/kotlin/com/hippo/ehviewer/util/AppConfig.kt
@@ -19,8 +19,6 @@ import android.os.Build
 import android.os.Environment
 import com.hippo.ehviewer.BuildConfig
 import com.hippo.ehviewer.client.parser.ParserUtils
-import com.hippo.unifile.UniFile
-import com.hippo.unifile.asUniFile
 import java.io.File
 import splitties.init.appCtx
 
@@ -59,7 +57,8 @@ object AppConfig {
     val defaultDownloadDir: File?
         get() = getDirInExternalAppDir(DOWNLOAD, false)
 
-    fun getTempDir(filename: String): UniFile? = getDirInExternalAppDir(TEMP)?.run { File(this, filename).asUniFile() }
+    fun getTempDir(filename: String): File? =
+        getDirInExternalAppDir(TEMP)?.run { File(this, filename).takeIf { it.ensureDirectory() } }
 
     val externalTempDir: File?
         get() = appCtx.externalCacheDir?.run { File(this, TEMP).takeIf { it.ensureDirectory() } }
diff --git a/app/src/main/kotlin/com/hippo/unifile/CachingFile.kt b/app/src/main/kotlin/com/hippo/unifile/CachingFile.kt
new file mode 100644
index 000000000..900ce298f
--- /dev/null
+++ b/app/src/main/kotlin/com/hippo/unifile/CachingFile.kt
@@ -0,0 +1,49 @@
+package com.hippo.unifile
+
+abstract class CachingFile<T : UniFile>(override val parent: T?) : UniFile {
+    private var cachePresent = false
+
+    private val allChildren by lazy {
+        cachePresent = true
+        list() ?: mutableListOf()
+    }
+
+    protected abstract fun list(): MutableList<T>?
+
+    protected fun popCacheIfPresent(file: T) {
+        if (cachePresent) {
+            synchronized(allChildren) {
+                allChildren.add(file)
+            }
+        }
+    }
+
+    protected fun evictCacheIfPresent(file: T) {
+        if (cachePresent) {
+            synchronized(allChildren) {
+                allChildren.remove(file)
+            }
+        }
+    }
+
+    protected fun replaceCacheIfPresent(old: T, new: T) {
+        if (cachePresent) {
+            synchronized(allChildren) {
+                val index = allChildren.indexOf(old)
+                if (index != -1) {
+                    allChildren[index] = new
+                }
+            }
+        }
+    }
+
+    override fun listFiles() = synchronized(allChildren) {
+        allChildren.toList()
+    }
+
+    override fun findFirst(filter: (String) -> Boolean) = synchronized(allChildren) {
+        allChildren.firstOrNull { filter(it.name!!) }
+    }
+
+    override fun findFile(displayName: String) = findFirst { it.equals(displayName, true) }
+}
diff --git a/app/src/main/kotlin/com/hippo/unifile/DocumentsContractApi21.kt b/app/src/main/kotlin/com/hippo/unifile/DocumentsContractApi21.kt
index 72bbf17ca..1e751cc1c 100644
--- a/app/src/main/kotlin/com/hippo/unifile/DocumentsContractApi21.kt
+++ b/app/src/main/kotlin/com/hippo/unifile/DocumentsContractApi21.kt
@@ -26,19 +26,8 @@ object DocumentsContractApi21 {
         DocumentsContract.createDocument(resolver, self, mimeType, displayName)
     }.getOrNull()
 
-    fun createDirectory(self: Uri, displayName: String) = createFile(self, DocumentsContract.Document.MIME_TYPE_DIR, displayName)
-
-    fun prepareTreeUri(treeUri: Uri): Uri = DocumentsContract.buildDocumentUriUsingTree(
-        treeUri,
-        DocumentsContract.getTreeDocumentId(treeUri),
-    )
-
-    // This is not a good approach as the document identifier is an opaque implementation detail of
-    // the provider, but works for ExternalStorageProvider
-    fun buildChildUri(uri: Uri, displayName: String): Uri = DocumentsContract.buildDocumentUriUsingTree(
-        uri,
-        DocumentsContract.getDocumentId(uri) + "/" + displayName,
-    )
+    fun prepareTreeUri(treeUri: Uri): Uri =
+        DocumentsContract.buildDocumentUriUsingTree(treeUri, DocumentsContract.getTreeDocumentId(treeUri))
 
     fun renameTo(self: Uri, displayName: String) = runCatching {
         DocumentsContract.renameDocument(resolver, self, displayName)
diff --git a/app/src/main/kotlin/com/hippo/unifile/MediaFile.kt b/app/src/main/kotlin/com/hippo/unifile/MediaFile.kt
index 74befa1df..682031dd8 100644
--- a/app/src/main/kotlin/com/hippo/unifile/MediaFile.kt
+++ b/app/src/main/kotlin/com/hippo/unifile/MediaFile.kt
@@ -48,12 +48,6 @@ class MediaFile(override val uri: Uri) : UniFile {
         return true
     }
 
-    override fun ensureDir() = false
-
-    override fun ensureFile() = isFile
-
-    override fun resolve(displayName: String) = error("MediaFile never have a children")
-
     override fun delete() = false
 
     override fun exists() = isFile
@@ -62,5 +56,7 @@ class MediaFile(override val uri: Uri) : UniFile {
 
     override fun findFirst(filter: (String) -> Boolean) = null
 
-    override fun renameTo(displayName: String) = false
+    override fun findFile(displayName: String) = null
+
+    override fun renameTo(displayName: String) = null
 }
diff --git a/app/src/main/kotlin/com/hippo/unifile/RawFile.kt b/app/src/main/kotlin/com/hippo/unifile/RawFile.kt
index 7b2a7d76d..4e32c61b0 100644
--- a/app/src/main/kotlin/com/hippo/unifile/RawFile.kt
+++ b/app/src/main/kotlin/com/hippo/unifile/RawFile.kt
@@ -22,45 +22,29 @@ import android.os.ParcelFileDescriptor.parseMode
 import android.webkit.MimeTypeMap
 import java.io.File
 
-class RawFile(override val parent: RawFile?, private var file: File) : UniFile {
-
-    private var cachePresent = false
-    private val allChildren by lazy {
-        cachePresent = true
-        file.listFiles().orEmpty().mapTo(mutableListOf()) { RawFile(this, it) }
+class RawFile(parent: RawFile?, private val file: File) : CachingFile<RawFile>(parent) {
+    override fun list() = file.listFiles()?.let { children ->
+        MutableList(children.size) { RawFile(this, children[it]) }
     }
 
-    private fun popCacheIfPresent(file: RawFile) {
-        if (cachePresent) {
-            synchronized(allChildren) {
-                allChildren.add(file)
-            }
-        }
-    }
-
-    private fun evictCacheIfPresent(file: RawFile) {
-        if (cachePresent) {
-            synchronized(allChildren) {
-                allChildren.remove(file)
-            }
-        }
-    }
-
-    override fun createFile(displayName: String): UniFile? {
-        val target = RawFile(this, File(file, displayName))
-        if (target.exists()) {
-            if (target.isFile) return target
+    private fun createFile(displayName: String, isFile: Boolean): UniFile? {
+        val child = findFile(displayName)
+        return if (child != null) {
+            child.takeIf { if (isFile) it.isFile else it.isDirectory }
         } else {
-            if (target.ensureFile()) return target
+            val target = File(file, displayName)
+            val created = if (isFile) target.createNewFile() else target.mkdir()
+            if (created) {
+                RawFile(this, target).also { popCacheIfPresent(it) }
+            } else {
+                null
+            }
         }
-        return null
     }
 
-    override fun createDirectory(displayName: String): UniFile? {
-        val target = RawFile(this, File(file, displayName))
-        if (target.ensureDir()) return target
-        return null
-    }
+    override fun createFile(displayName: String) = createFile(displayName, true)
+
+    override fun createDirectory(displayName: String) = createFile(displayName, false)
 
     override val uri: Uri
         get() = Uri.fromFile(file)
@@ -86,46 +70,19 @@ class RawFile(override val parent: RawFile?, private var file: File) : UniFile {
 
     override fun canWrite() = file.canWrite()
 
-    override fun ensureDir(): Boolean {
-        if (file.isDirectory) return true
-        if (file.mkdirs()) {
-            parent?.popCacheIfPresent(this)
-            return true
-        }
-        return false
-    }
-
-    override fun ensureFile(): Boolean {
-        if (file.exists()) return file.isFile
-        parent?.ensureDir()
-        val success = file.createNewFile()
-        if (success) parent?.popCacheIfPresent(this)
-        return success
-    }
-
-    override fun resolve(displayName: String) = RawFile(this, File(file, displayName))
-
     override fun delete() = file.deleteRecursively().also {
         if (it) parent?.evictCacheIfPresent(this)
     }
 
     override fun exists() = file.exists()
 
-    override fun listFiles() = synchronized(allChildren) {
-        allChildren.toList()
-    }
-
-    override fun findFirst(filter: (String) -> Boolean) = synchronized(allChildren) {
-        allChildren.firstOrNull { filter(it.name) }
-    }
-
-    override fun renameTo(displayName: String): Boolean {
+    override fun renameTo(displayName: String): UniFile? {
         val target = File(file.parentFile, displayName)
-        if (file.renameTo(target)) {
-            file = target
-            return true
+        return if (file.renameTo(target)) {
+            RawFile(parent, target).also { parent?.replaceCacheIfPresent(this, it) }
+        } else {
+            null
         }
-        return false
     }
 
     override fun openFileDescriptor(mode: String): ParcelFileDescriptor = open(file, parseMode(mode))
diff --git a/app/src/main/kotlin/com/hippo/unifile/SingleDocumentFile.kt b/app/src/main/kotlin/com/hippo/unifile/SingleDocumentFile.kt
index 961febe25..ffa6ab117 100644
--- a/app/src/main/kotlin/com/hippo/unifile/SingleDocumentFile.kt
+++ b/app/src/main/kotlin/com/hippo/unifile/SingleDocumentFile.kt
@@ -18,7 +18,6 @@ package com.hippo.unifile
 import android.net.Uri
 
 class SingleDocumentFile(override val uri: Uri) : UniFile {
-
     override fun createFile(displayName: String) = null
 
     override fun createDirectory(displayName: String) = null
@@ -41,12 +40,6 @@ class SingleDocumentFile(override val uri: Uri) : UniFile {
 
     override fun canWrite() = DocumentsContractApi19.canWrite(uri)
 
-    override fun ensureDir() = isDirectory
-
-    override fun ensureFile() = isFile
-
-    override fun resolve(displayName: String) = error("SingleDocumentFile never have a children")
-
     override fun delete() = DocumentsContractApi19.delete(uri)
 
     override fun exists() = DocumentsContractApi19.exists(uri)
@@ -55,5 +48,7 @@ class SingleDocumentFile(override val uri: Uri) : UniFile {
 
     override fun findFirst(filter: (String) -> Boolean) = null
 
-    override fun renameTo(displayName: String) = false
+    override fun findFile(displayName: String) = null
+
+    override fun renameTo(displayName: String) = null
 }
diff --git a/app/src/main/kotlin/com/hippo/unifile/TreeDocumentFile.kt b/app/src/main/kotlin/com/hippo/unifile/TreeDocumentFile.kt
index 67245713b..303a8d078 100644
--- a/app/src/main/kotlin/com/hippo/unifile/TreeDocumentFile.kt
+++ b/app/src/main/kotlin/com/hippo/unifile/TreeDocumentFile.kt
@@ -22,77 +22,58 @@ import android.webkit.MimeTypeMap
 import splitties.init.appCtx
 
 class TreeDocumentFile(
-    override val parent: TreeDocumentFile?,
-    uri: Uri,
-    name: String = getFilenameForUri(uri),
+    parent: TreeDocumentFile?,
+    override val uri: Uri,
+    name: String? = null,
     mimeType: String? = null,
-) : UniFile {
-    private var cachePresent = false
-    private val allChildren by lazy {
-        cachePresent = true
-        queryChildren()
-    }
-
-    private fun popCacheIfPresent(file: TreeDocumentFile) {
-        if (cachePresent) {
-            synchronized(allChildren) {
-                allChildren.add(file)
+) : CachingFile<TreeDocumentFile>(parent) {
+    override fun list() = runCatching {
+        val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(uri, DocumentsContract.getDocumentId(uri))
+        appCtx.contentResolver.query(childrenUri, projection, null, null, null)?.use { c ->
+            MutableList(c.count) {
+                c.moveToNext()
+                val documentId = c.getString(0)
+                val documentUri = DocumentsContract.buildDocumentUriUsingTree(uri, documentId)
+                val displayName = c.getString(1)
+                val mimeType = c.getString(2)
+                TreeDocumentFile(this, documentUri, displayName, mimeType)
             }
         }
-    }
+    }.getOrNull()
 
-    private fun evictCacheIfPresent(file: TreeDocumentFile) {
-        if (cachePresent) {
-            synchronized(allChildren) {
-                allChildren.remove(file)
-            }
+    private fun createFile(displayName: String, mimeType: String) =
+        DocumentsContractApi21.createFile(uri, mimeType, displayName)?.let { result ->
+            TreeDocumentFile(this, result, displayName, mimeType).also { popCacheIfPresent(it) }
         }
-    }
 
     override fun createFile(displayName: String): UniFile? {
         val child = findFile(displayName)
-        if (child != null) {
-            if (child.isFile) return child
+        return if (child != null) {
+            child.takeIf { it.isFile }
         } else {
             val extension = displayName.substringAfterLast('.', "").ifEmpty { null }?.lowercase()
             val mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension) ?: "application/octet-stream"
-            val result = DocumentsContractApi21.createFile(uri, mimeType, displayName)
-            if (result != null) {
-                val f = TreeDocumentFile(this, result, displayName, mimeType)
-                popCacheIfPresent(f)
-                return f
-            }
+            createFile(displayName, mimeType)
         }
-        return null
     }
 
     override fun createDirectory(displayName: String): UniFile? {
         val child = findFile(displayName)
-        if (child != null) {
-            if (child.isDirectory) return null
+        return if (child != null) {
+            child.takeIf { it.isDirectory }
         } else {
-            val result = DocumentsContractApi21.createDirectory(uri, displayName)
-            if (result != null) {
-                val d = TreeDocumentFile(this, result, displayName, Document.MIME_TYPE_DIR)
-                popCacheIfPresent(d)
-                return d
-            }
+            createFile(displayName, Document.MIME_TYPE_DIR)
         }
-        return null
     }
 
-    private var mimeType = mimeType
-        get() {
-            if (field == null) {
-                field = DocumentsContractApi19.getRawType(uri)
-            }
-            return field
-        }
+    override val name by lazy {
+        name ?: DocumentsContractApi19.getName(uri)!!
+    }
+
+    private val mimeType by lazy {
+        mimeType ?: DocumentsContractApi19.getRawType(uri)
+    }
 
-    override var uri = uri
-        private set
-    override var name = name
-        private set
     override val type: String?
         get() = mimeType.takeUnless { isDirectory }
     override val isDirectory: Boolean
@@ -108,61 +89,18 @@ class TreeDocumentFile(
 
     override fun canWrite() = DocumentsContractApi19.canWrite(uri)
 
-    override fun ensureDir(): Boolean {
-        if (isDirectory) return true
-        if (isFile) return false
-        return if (parent != null && parent.ensureDir()) {
-            parent.createDirectory(name) != null
-        } else {
-            false
-        }
-    }
-
-    override fun ensureFile(): Boolean {
-        if (isFile) return true
-        if (isDirectory) return false
-        return if (parent != null && parent.ensureDir()) {
-            parent.createFile(name) != null
-        } else {
-            false
-        }
-    }
-
-    override fun resolve(displayName: String): UniFile {
-        val childUri = DocumentsContractApi21.buildChildUri(uri, displayName)
-        return TreeDocumentFile(this, childUri, displayName)
-    }
-
     override fun delete() = DocumentsContractApi19.delete(uri).also {
         if (it) parent?.evictCacheIfPresent(this)
     }
 
     override fun exists() = DocumentsContractApi19.exists(uri)
 
-    override fun listFiles() = synchronized(allChildren) {
-        allChildren.toList()
-    }
-
-    override fun findFirst(filter: (String) -> Boolean) = synchronized(allChildren) {
-        allChildren.firstOrNull { filter(it.name) }
-    }
-
-    override fun renameTo(displayName: String): Boolean {
-        val result = DocumentsContractApi21.renameTo(uri, displayName)
-        if (result != null) {
-            uri = result
-            name = displayName
-            mimeType = null
-            return true
+    override fun renameTo(displayName: String): UniFile? =
+        DocumentsContractApi21.renameTo(uri, displayName)?.let { result ->
+            TreeDocumentFile(parent, result, displayName).also {
+                parent?.replaceCacheIfPresent(this, it)
+            }
         }
-        return false
-    }
-}
-
-// Technically the Uris should be treated as opaque, but it works for ExternalStorageProvider
-private fun getFilenameForUri(uri: Uri): String {
-    val path = requireNotNull(uri.path)
-    return path.substringAfterLast('/')
 }
 
 private val projection = arrayOf(
@@ -170,18 +108,3 @@ private val projection = arrayOf(
     Document.COLUMN_DISPLAY_NAME,
     Document.COLUMN_MIME_TYPE,
 )
-
-private fun TreeDocumentFile.queryChildren(): MutableList<TreeDocumentFile> {
-    val self = uri
-    val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(self, DocumentsContract.getDocumentId(self))
-    return appCtx.contentResolver.query(childrenUri, projection, null, null, null)?.use { c ->
-        MutableList(c.count) {
-            c.moveToNext()
-            val documentId = c.getString(0)
-            val documentUri = DocumentsContract.buildDocumentUriUsingTree(self, documentId)
-            val displayName = c.getString(1)
-            val mimeType = c.getString(2)
-            TreeDocumentFile(this, documentUri, displayName, mimeType)
-        }
-    } ?: mutableListOf()
-}
diff --git a/app/src/main/kotlin/com/hippo/unifile/UniFile.kt b/app/src/main/kotlin/com/hippo/unifile/UniFile.kt
index 0aa341b08..4103b555c 100644
--- a/app/src/main/kotlin/com/hippo/unifile/UniFile.kt
+++ b/app/src/main/kotlin/com/hippo/unifile/UniFile.kt
@@ -152,31 +152,6 @@ sealed interface UniFile {
      */
     fun canWrite(): Boolean
 
-    /**
-     * It works like mkdirs, but it will return true if the UniFile is directory
-     *
-     * @return `true` if the directory was created
-     * or if the directory already existed.
-     */
-    fun ensureDir(): Boolean
-
-    /**
-     * Make sure the UniFile is file
-     *
-     * @return `true` if the file can be created
-     * or if the file already existed.
-     */
-    fun ensureFile(): Boolean
-
-    /**
-     * Get child file of this directory, the child might not exist.
-     *
-     * @return the child file
-     */
-    fun resolve(displayName: String): UniFile
-
-    operator fun div(name: String) = resolve(name)
-
     /**
      * Deletes this file.
      *
@@ -207,7 +182,7 @@ sealed interface UniFile {
      *
      * @return the file if found it, or `null`.
      */
-    fun findFile(displayName: String) = resolve(displayName).takeIf { it.exists() }
+    fun findFile(displayName: String): UniFile?
 
     /**
      * Renames this file to `displayName`.
@@ -218,18 +193,18 @@ sealed interface UniFile {
      *
      *
      * Some providers may need to create a new file to reflect the rename,
-     * potentially with a different MIME type, so [.getUri] and
-     * [.getType] may change to reflect the rename.
+     * potentially with a different MIME type, so [uri] and
+     * [type] may change to reflect the rename.
      *
      *
      * When renaming a directory, children previously enumerated through
-     * [.listFiles] may no longer be valid.
+     * [listFiles] may no longer be valid.
      *
      * @param displayName the new display name.
-     * @return true on success.
+     * @return the new file after the rename, or `null` if failed.
      * @see android.provider.DocumentsContract.renameDocument
      */
-    fun renameTo(displayName: String): Boolean
+    fun renameTo(displayName: String): UniFile?
 
     companion object {
         fun fromFile(file: File) = RawFile(null, file)
diff --git a/app/src/main/kotlin/com/hippo/unifile/UniFileExtensions.kt b/app/src/main/kotlin/com/hippo/unifile/UniFileExtensions.kt
index d9b0c4dbf..c6c726f03 100644
--- a/app/src/main/kotlin/com/hippo/unifile/UniFileExtensions.kt
+++ b/app/src/main/kotlin/com/hippo/unifile/UniFileExtensions.kt
@@ -46,6 +46,3 @@ val Uri.displayPath: String?
         }
         return toString()
     }
-
-fun UniFile.ensureDirOrThrow() =
-    check(ensureDir()) { "Failed to create directory: ${uri.displayPath}" }
diff --git a/app/src/main/kotlin/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt b/app/src/main/kotlin/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
index 428ef3474..ac5a4a69f 100644
--- a/app/src/main/kotlin/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
+++ b/app/src/main/kotlin/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
@@ -20,6 +20,7 @@ import android.Manifest
 import android.app.assist.AssistContent
 import android.content.ClipData
 import android.content.ContentValues
+import android.content.Context
 import android.content.Intent
 import android.graphics.ColorMatrix
 import android.graphics.ColorMatrixColorFilter
@@ -80,6 +81,7 @@ import com.hippo.ehviewer.gallery.EhPageLoader
 import com.hippo.ehviewer.gallery.PageLoader2
 import com.hippo.ehviewer.ui.EhActivity
 import com.hippo.ehviewer.ui.reader.SettingsPager
+import com.hippo.ehviewer.ui.screen.implicit
 import com.hippo.ehviewer.ui.setMD3Content
 import com.hippo.ehviewer.ui.tools.DialogState
 import com.hippo.ehviewer.util.AppConfig
@@ -376,12 +378,11 @@ class ReaderActivity : EhActivity() {
     private suspend fun makeToast(@StringRes resId: Int) = makeToast(getString(resId))
 
     private fun provideImage(index: Int): Uri? = AppConfig.externalTempDir?.let { dir ->
-        mGalleryProvider?.saveToDir(index, dir.asUniFile())?.name?.let {
-            FileProvider.getUriForFile(
-                this,
-                BuildConfig.APPLICATION_ID + ".fileprovider",
-                File(dir, it),
-            )
+        mGalleryProvider?.run {
+            getImageFilename(index)?.let { filename ->
+                val file = File(dir, filename).takeIf { save(index, it.asUniFile()) } ?: return null
+                FileProvider.getUriForFile(implicit<Context>(), BuildConfig.APPLICATION_ID + ".fileprovider", file)
+            }
         }
     }