diff --git a/app/src/main/java/io/legado/app/help/AppWebDav.kt b/app/src/main/java/io/legado/app/help/AppWebDav.kt
index 2ef0bce5e..58a5e0464 100644
--- a/app/src/main/java/io/legado/app/help/AppWebDav.kt
+++ b/app/src/main/java/io/legado/app/help/AppWebDav.kt
@@ -139,7 +139,6 @@ object AppWebDav {
         authorization?.let {
             val webDav = WebDav(rootWebDavUrl + name, it)
             webDav.downloadTo(zipFilePath, true)
-            @Suppress("BlockingMethodInNonBlockingContext")
             ZipUtils.unzipFile(zipFilePath, Backup.backupPath)
             Restore.restoreDatabase()
             Restore.restoreConfig()
diff --git a/app/src/main/java/io/legado/app/help/BookHelp.kt b/app/src/main/java/io/legado/app/help/BookHelp.kt
index aa31d30c7..48b837753 100644
--- a/app/src/main/java/io/legado/app/help/BookHelp.kt
+++ b/app/src/main/java/io/legado/app/help/BookHelp.kt
@@ -138,12 +138,12 @@ object BookHelp {
         try {
             var bytes = analyzeUrl.getByteArrayAwait()
             //某些图片被加密，需要进一步解密
-            bookSource?.getContentRule()?.imageDecode?.let {
-                if (it.isBlank()) {
+            bookSource?.getContentRule()?.imageDecode?.let { imageDecode ->
+                if (imageDecode.isBlank()) {
                     return@let
                 }
                 kotlin.runCatching {
-                    bookSource.evalJS(it) {
+                    bookSource.evalJS(imageDecode) {
                         put("book", book)
                         put("result", bytes)
                         put("src", src)
@@ -155,11 +155,11 @@ object BookHelp {
                 }
             }
             FileUtils.createFileIfNotExist(
-                    downloadDir,
-                    cacheFolderName,
-                    book.getFolderName(),
-                    cacheImageFolderName,
-                    "${MD5Utils.md5Encode16(src)}.${getImageSuffix(src)}"
+                downloadDir,
+                cacheFolderName,
+                book.getFolderName(),
+                cacheImageFolderName,
+                "${MD5Utils.md5Encode16(src)}.${getImageSuffix(src)}"
             ).writeBytes(bytes)
         } catch (e: Exception) {
             AppLog.putDebug("${src}下载错误", e)
@@ -323,7 +323,7 @@ object BookHelp {
         newChapterList: List<BookChapter>,
         oldChapterListSize: Int = 0
     ): Int {
-        if (oldDurChapterIndex == 0) return oldDurChapterIndex
+        if (oldDurChapterIndex == 0) return 0
         if (newChapterList.isEmpty()) return oldDurChapterIndex
         val oldChapterNum = getChapterNum(oldDurChapterName)
         val oldName = getPureChapterName(oldDurChapterName)
@@ -370,6 +370,7 @@ object BookHelp {
         Pattern.compile(".*?第([\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟]+)[章节篇回集话]")
     }
 
+    @Suppress("RegExpSimplifiable")
     private val chapterNamePattern2 by lazy {
         Pattern.compile("^(?:[\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟]+[,:、])*([\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟]+)(?:[,:、]|\\.[^\\d])")
     }
@@ -397,7 +398,7 @@ object BookHelp {
         return@lazy "[^\\w\\u4E00-\\u9FEF〇\\u3400-\\u4DBF\\u20000-\\u2A6DF\\u2A700-\\u2EBEF]".toRegex()
     }
 
-    @Suppress("RegExpUnnecessaryNonCapturingGroup")
+    @Suppress("RegExpUnnecessaryNonCapturingGroup", "RegExpSimplifiable")
     private val regexB by lazy {
         //章节序号，排除处于结尾的状况，避免将章节名替换为空字串
         return@lazy "^.*?第(?:[\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟]+)[章节篇回集话](?!$)|^(?:[\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟]+[,:、])*(?:[\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟]+)(?:[,:、](?!$)|\\.(?=[^\\d]))".toRegex()