Merge remote-tracking branch 'origin/master'

app/src/main/java/io/legado/app/model/localBook/EpubFile.kt

@@ -119,9 +119,10 @@ class EpubFile(var book: Book) {
         /**
          * <image width="1038" height="670" xlink:href="..."/>
          * ...titlepage.xhtml
+         * 大多数epub文件的封面页都会带有cover，可以一定程度上解决封面读取问题
          */
         if (chapter.url.contains("titlepage.xhtml") ||
-            chapter.url.contains("cover.xhtml")
+            chapter.url.contains("cover")
         ) {
             return "<img src=\"cover.jpeg\" />"
         }

app/src/main/java/io/legado/app/ui/book/cache/CacheViewModel.kt

@@ -123,9 +123,7 @@ class CacheViewModel(application: Application) : BaseViewModel(application) {
             exportMsg[book.bookUrl] = context.getString(R.string.export_success)
             upAdapterLiveData.postValue(book.bookUrl)
         }.onFinally {
-            mutex.withLock {
-                exportNumber--
-            }
+            exportNumber--
         }
     }
 
@@ -288,9 +286,7 @@ class CacheViewModel(application: Application) : BaseViewModel(application) {
             exportMsg[book.bookUrl] = context.getString(R.string.export_success)
             upAdapterLiveData.postValue(book.bookUrl)
         }.onFinally {
-            mutex.withLock {
-                exportNumber--
-            }
+            exportNumber--
         }
     }