Convert PageLoader.getPages to suspending function (#8917)

app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadManager.kt

@@ -15,7 +15,6 @@ import eu.kanade.tachiyomi.util.lang.launchIO
 import eu.kanade.tachiyomi.util.system.logcat
 import kotlinx.coroutines.runBlocking
 import logcat.LogPriority
-import rx.Observable
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.get
 
@@ -165,23 +164,21 @@ class DownloadManager(
      * @param source the source of the chapter.
      * @param manga the manga of the chapter.
      * @param chapter the downloaded chapter.
-     * @return an observable containing the list of pages from the chapter.
+     * @return the list of pages from the chapter.
      */
-    fun buildPageList(source: Source, manga: Manga, chapter: Chapter): Observable<List<Page>> {
+    fun buildPageList(source: Source, manga: Manga, chapter: Chapter): List<Page> {
         val chapterDir = provider.findChapterDir(chapter.name, chapter.scanlator, manga.title, source)
-        return Observable.fromCallable {
-            val files = chapterDir?.listFiles().orEmpty()
-                .filter { "image" in it.type.orEmpty() }
+        val files = chapterDir?.listFiles().orEmpty()
+            .filter { "image" in it.type.orEmpty() }
 
-            if (files.isEmpty()) {
-                throw Exception(context.getString(R.string.page_list_empty_error))
-            }
-
-            files.sortedBy { it.name }
-                .mapIndexed { i, file ->
-                    Page(i, uri = file.uri).apply { status = Page.State.READY }
-                }
+        if (files.isEmpty()) {
+            throw Exception(context.getString(R.string.page_list_empty_error))
         }
+
+        return files.sortedBy { it.name }
+            .mapIndexed { i, file ->
+                Page(i, uri = file.uri).apply { status = Page.State.READY }
+            }
     }
 
     /**

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

@@ -11,7 +11,6 @@ import eu.kanade.tachiyomi.source.Source
 import eu.kanade.tachiyomi.source.SourceManager
 import eu.kanade.tachiyomi.source.online.HttpSource
 import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
-import eu.kanade.tachiyomi.util.lang.awaitSingle
 import eu.kanade.tachiyomi.util.lang.withIOContext
 import eu.kanade.tachiyomi.util.system.logcat
 
@@ -42,7 +41,7 @@ class ChapterLoader(
                 val loader = getPageLoader(chapter)
                 chapter.pageLoader = loader
 
-                val pages = loader.getPages().awaitSingle()
+                val pages = loader.getPages()
                     .onEach { it.chapter = chapter }
 
                 if (pages.isEmpty()) {

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

@@ -14,10 +14,9 @@ import java.io.FileInputStream
 class DirectoryPageLoader(val file: File) : PageLoader() {
 
     /**
-     * Returns an observable containing the pages found on this directory ordered with a natural
-     * comparator.
+     * Returns the pages found on this directory ordered with a natural comparator.
      */
-    override fun getPages(): Observable<List<ReaderPage>> {
+    override suspend fun getPages(): List<ReaderPage> {
         return file.listFiles()
             ?.filter { !it.isDirectory && ImageUtil.isImage(it.name) { FileInputStream(it) } }
             ?.sortedWith { f1, f2 -> f1.name.compareToCaseInsensitiveNaturalOrder(f2.name) }
@@ -27,8 +26,7 @@ class DirectoryPageLoader(val file: File) : PageLoader() {
                     stream = streamFn
                     status = Page.State.READY
                 }
-            }
-            .let { Observable.just(it) }
+            } ?: emptyList()
     }
 
     /**

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

@@ -37,9 +37,9 @@ class DownloadPageLoader(
     }
 
     /**
-     * Returns an observable containing the pages found on this downloaded chapter.
+     * Returns the pages found on this downloaded chapter.
      */
-    override fun getPages(): Observable<List<ReaderPage>> {
+    override suspend fun getPages(): List<ReaderPage> {
         val dbChapter = chapter.chapter
         val chapterPath = downloadProvider.findChapterDir(dbChapter.name, dbChapter.scanlator, manga.title, source)
         return if (chapterPath?.isFile == true) {
@@ -49,22 +49,20 @@ class DownloadPageLoader(
         }
     }
 
-    private fun getPagesFromArchive(chapterPath: UniFile): Observable<List<ReaderPage>> {
+    private suspend fun getPagesFromArchive(chapterPath: UniFile): List<ReaderPage> {
         val loader = ZipPageLoader(File(chapterPath.filePath!!)).also { zipPageLoader = it }
         return loader.getPages()
     }
 
-    private fun getPagesFromDirectory(): Observable<List<ReaderPage>> {
-        return downloadManager.buildPageList(source, manga, chapter.chapter.toDomainChapter()!!)
-            .map { pages ->
-                pages.map { page ->
-                    ReaderPage(page.index, page.url, page.imageUrl) {
-                        context.contentResolver.openInputStream(page.uri ?: Uri.EMPTY)!!
-                    }.apply {
-                        status = Page.State.READY
-                    }
-                }
+    private fun getPagesFromDirectory(): List<ReaderPage> {
+        val pages = downloadManager.buildPageList(source, manga, chapter.chapter.toDomainChapter()!!)
+        return pages.map { page ->
+            ReaderPage(page.index, page.url, page.imageUrl) {
+                context.contentResolver.openInputStream(page.uri ?: Uri.EMPTY)!!
+            }.apply {
+                status = Page.State.READY
             }
+        }
     }
 
     override fun getPage(page: ReaderPage): Observable<Page.State> {

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

@@ -25,10 +25,9 @@ class EpubPageLoader(file: File) : PageLoader() {
     }
 
     /**
-     * Returns an observable containing the pages found on this zip archive ordered with a natural
-     * comparator.
+     * Returns the pages found on this zip archive ordered with a natural comparator.
      */
-    override fun getPages(): Observable<List<ReaderPage>> {
+    override suspend fun getPages(): List<ReaderPage> {
         return epub.getImagesFromPages()
             .mapIndexed { i, path ->
                 val streamFn = { epub.getInputStream(epub.getEntry(path)!!) }
@@ -37,7 +36,6 @@ class EpubPageLoader(file: File) : PageLoader() {
                     status = Page.State.READY
                 }
             }
-            .let { Observable.just(it) }
     }
 
     /**

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

@@ -8,6 +8,7 @@ import eu.kanade.tachiyomi.ui.reader.model.ReaderChapter
 import eu.kanade.tachiyomi.ui.reader.model.ReaderPage
 import eu.kanade.tachiyomi.util.lang.plusAssign
 import eu.kanade.tachiyomi.util.system.logcat
+import kotlinx.coroutines.CancellationException
 import logcat.LogPriority
 import rx.Completable
 import rx.Observable
@@ -83,18 +84,22 @@ class HttpPageLoader(
     }
 
     /**
-     * Returns an observable with the page list for a chapter. It tries to return the page list from
-     * the local cache, otherwise fallbacks to network.
+     * Returns the page list for a chapter. It tries to return the page list from the local cache,
+     * otherwise fallbacks to network.
      */
-    override fun getPages(): Observable<List<ReaderPage>> {
-        return Observable.fromCallable { chapterCache.getPageListFromCache(chapter.chapter.toDomainChapter()!!) }
-            .onErrorResumeNext { source.fetchPageList(chapter.chapter) }
-            .map { pages ->
-                pages.mapIndexed { index, page ->
-                    // Don't trust sources and use our own indexing
-                    ReaderPage(index, page.url, page.imageUrl)
-                }
+    override suspend fun getPages(): List<ReaderPage> {
+        val pages = try {
+            chapterCache.getPageListFromCache(chapter.chapter.toDomainChapter()!!)
+        } catch (e: Throwable) {
+            if (e is CancellationException) {
+                throw e
             }
+            source.getPageList(chapter.chapter)
+        }
+        return pages.mapIndexed { index, page ->
+            // Don't trust sources and use our own indexing
+            ReaderPage(index, page.url, page.imageUrl)
+        }
     }
 
     /**

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

@@ -27,10 +27,9 @@ abstract class PageLoader {
     }
 
     /**
-     * Returns an observable containing the list of pages of a chapter. Only the first emission
-     * will be used.
+     * Returns the list of pages of a chapter.
      */
-    abstract fun getPages(): Observable<List<ReaderPage>>
+    abstract suspend fun getPages(): List<ReaderPage>
 
     /**
      * Returns an observable that should inform of the progress of the page

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

@@ -38,10 +38,10 @@ class RarPageLoader(file: File) : PageLoader() {
     }
 
     /**
-     * Returns an observable containing the pages found on this rar archive ordered with a natural
+     * Returns an RxJava Single containing the pages found on this rar archive ordered with a natural
      * comparator.
      */
-    override fun getPages(): Observable<List<ReaderPage>> {
+    override suspend fun getPages(): List<ReaderPage> {
         return archive.fileHeaders.asSequence()
             .filter { !it.isDirectory && ImageUtil.isImage(it.fileName) { archive.getInputStream(it) } }
             .sortedWith { f1, f2 -> f1.fileName.compareToCaseInsensitiveNaturalOrder(f2.fileName) }
@@ -51,7 +51,7 @@ class RarPageLoader(file: File) : PageLoader() {
                     status = Page.State.READY
                 }
             }
-            .let { Observable.just(it.toList()) }
+            .toList()
     }
 
     /**

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

@@ -33,10 +33,9 @@ class ZipPageLoader(file: File) : PageLoader() {
     }
 
     /**
-     * Returns an observable containing the pages found on this zip archive ordered with a natural
-     * comparator.
+     * Returns the pages found on this zip archive ordered with a natural comparator.
      */
-    override fun getPages(): Observable<List<ReaderPage>> {
+    override suspend fun getPages(): List<ReaderPage> {
         return zip.entries().asSequence()
             .filter { !it.isDirectory && ImageUtil.isImage(it.name) { zip.getInputStream(it) } }
             .sortedWith { f1, f2 -> f1.name.compareToCaseInsensitiveNaturalOrder(f2.name) }
@@ -46,7 +45,7 @@ class ZipPageLoader(file: File) : PageLoader() {
                     status = Page.State.READY
                 }
             }
-            .let { Observable.just(it.toList()) }
+            .toList()
     }
 
     /**