Replace RxJava in webtoonholder

app/src/main/java/eu/kanade/tachiyomi/ui/reader/viewer/webtoon/WebtoonPageHolder.kt

@@ -23,14 +23,15 @@ import eu.kanade.tachiyomi.ui.reader.viewer.ReaderPageImageView
 import eu.kanade.tachiyomi.ui.reader.viewer.ReaderProgressBar
 import eu.kanade.tachiyomi.util.system.ImageUtil
 import eu.kanade.tachiyomi.util.system.dpToPx
+import eu.kanade.tachiyomi.util.system.launchIO
+import eu.kanade.tachiyomi.util.system.withIOContext
+import eu.kanade.tachiyomi.util.system.withUIContext
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.MainScope
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
-import rx.Observable
-import rx.Subscription
-import rx.android.schedulers.AndroidSchedulers
-import rx.schedulers.Schedulers
+import kotlinx.coroutines.supervisorScope
+import kotlinx.coroutines.suspendCancellableCoroutine
 import java.io.BufferedInputStream
 import java.io.InputStream
 
@@ -85,22 +86,11 @@ class WebtoonPageHolder(
      */
     private var loadJob: Job? = null
 
-    /**
-     * Job for status changes of the page.
-     */
-    private var statusJob: Job? = null
-
     /**
      * Job for progress changes of the page.
      */
     private var progressJob: Job? = null
 
-    /**
-     * Subscription used to read the header of the image. This is needed in order to instantiate
-     * the appropriate image view depending if the image is animated (GIF).
-     */
-    private var readImageHeaderSubscription: Subscription? = null
-
     init {
         refreshLayoutParams()
         frame.setBackgroundColor(Color.BLACK)
@@ -136,7 +126,6 @@ class WebtoonPageHolder(
     override fun recycle() {
         cancelLoadJob()
         cancelProgressJob()
-        unsubscribeReadImageHeader()
 
         removeDecodeErrorLayout()
         frame.recycle()
@@ -150,13 +139,14 @@ class WebtoonPageHolder(
      */
     private fun launchLoadJob() {
         cancelLoadJob()
+        loadJob = scope.launch { loadPageAndProcessStatus() }
+    }
 
+    private suspend fun loadPageAndProcessStatus() {
         val page = page ?: return
         val loader = page.chapter.pageLoader ?: return
-        loadJob = scope.launch {
-            loader.loadPage(page)
-        }
-        statusJob = scope.launch {
+        supervisorScope {
+            launchIO { loader.loadPage(page) }
             page.statusFlow.collectLatest { processStatus(it) }
         }
     }
@@ -168,7 +158,6 @@ class WebtoonPageHolder(
         cancelProgressJob()
 
         val page = page ?: return
-
         progressJob = scope.launch {
             page.progressFlow.collectLatest { value -> progressBar.setProgress(value) }
         }
@@ -179,7 +168,7 @@ class WebtoonPageHolder(
      *
      * @param status the new status of the page.
      */
-    private fun processStatus(status: Page.State) {
+    private suspend fun processStatus(status: Page.State) {
         when (status) {
             Page.State.QUEUE -> setQueued()
             Page.State.LOAD_PAGE -> setLoading()
@@ -203,9 +192,6 @@ class WebtoonPageHolder(
      */
     private fun cancelLoadJob() {
         loadJob?.cancel()
-        loadJob = null
-        statusJob?.cancel()
-        statusJob = null
     }
 
     /**
@@ -213,15 +199,6 @@ class WebtoonPageHolder(
      */
     private fun cancelProgressJob() {
         progressJob?.cancel()
-        progressJob = null
-    }
-
-    /**
-     * Unsubscribes from the read image header subscription.
-     */
-    private fun unsubscribeReadImageHeader() {
-        removeSubscription(readImageHeaderSubscription)
-        readImageHeaderSubscription = null
     }
 
     /**
@@ -257,48 +234,40 @@ class WebtoonPageHolder(
     /**
      * Called when the page is ready.
      */
-    private fun setImage() {
+    private suspend fun setImage() {
         progressContainer.isVisible = true
         progressBar.isVisible = true
         progressBar.completeAndFadeOut()
         retryContainer?.isVisible = false
         removeDecodeErrorLayout()
 
-        unsubscribeReadImageHeader()
         val streamFn = page?.stream ?: return
 
-        var openStream: InputStream? = null
-        readImageHeaderSubscription = Observable
-            .fromCallable {
+        val (openStream, isAnimated) = withIOContext {
             val stream = streamFn().buffered(16)
-                openStream = process(stream)
+            val openStream = process(stream)
 
-                ImageUtil.isAnimatedAndSupported(stream)
+            val isAnimated = ImageUtil.isAnimatedAndSupported(stream)
+            Pair(openStream, isAnimated)
         }
-            .subscribeOn(Schedulers.io())
-            .observeOn(AndroidSchedulers.mainThread())
-            .doOnNext { isAnimated ->
+
+        withUIContext {
             frame.setImage(
-                    openStream!!,
+                openStream,
                 isAnimated,
                 ReaderPageImageView.Config(
                     zoomDuration = viewer.config.doubleTapAnimDuration,
                     minimumScaleType = SubsamplingScaleImageView.SCALE_TYPE_FIT_WIDTH,
-                        cropBorders =
-                        if (viewer.hasMargins) {
-                            viewer.config.verticalCropBorders
-                        } else {
-                            viewer.config.webtoonCropBorders
+                    cropBorders = viewer.config.run {
+                        if (viewer.hasMargins) { verticalCropBorders } else { webtoonCropBorders }
                     },
                 ),
             )
         }
-            // Keep the Rx stream alive to close the input stream only when unsubscribed
-            .flatMap { Observable.never<Unit>() }
-            .doOnUnsubscribe { openStream?.close() }
-            .subscribe({}, {})
-
-        addSubscription(readImageHeaderSubscription)
+        // Suspend the coroutine to close the input stream only when the WebtoonPageHolder is recycled
+        suspendCancellableCoroutine<Nothing> { continuation ->
+            continuation.invokeOnCancellation { openStream.close() }
+        }
     }
 
     private fun process(imageStream: BufferedInputStream): InputStream {