Download manager rewrite (#535)

* Saving to SD working

* Rename imagePath to uri

* Handle android < 21

* Minor changes

* Separate downloader from the manager. Optimize folder lookups

* Persist downloads across restarts

* Fix for #511

* Updated ReactiveNetwork. Add some documentation

* More documentation and minor fixes

* Handle persistent notifications. Other minor changes

* Improve downloader and add documentation

* Rename pageNumber to index in Page class

* Remove unused methods

* Use chop method

* Make sure dest dir is created

* Reset downloads dir preference

* Use invalidate options menu in download fragment and fix wrong condition

* Fix empty download queue after application restart

* Use addAll method in download queue to avoid too many notifications

* Inform download manager changes

app/src/main/java/eu/kanade/tachiyomi/ui/download/DownloadFragment.kt

@@ -6,6 +6,7 @@ import android.view.*
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.download.DownloadService
 import eu.kanade.tachiyomi.data.download.model.Download
+import eu.kanade.tachiyomi.data.source.model.Page
 import eu.kanade.tachiyomi.ui.base.fragment.BaseRxFragment
 import eu.kanade.tachiyomi.ui.main.MainActivity
 import eu.kanade.tachiyomi.util.plusAssign
@@ -30,21 +31,6 @@ class DownloadFragment : BaseRxFragment<DownloadPresenter>() {
      */
     private lateinit var adapter: DownloadAdapter
 
-    /**
-     * Menu item to start the queue.
-     */
-    private var startButton: MenuItem? = null
-
-    /**
-     * Menu item to pause the queue.
-     */
-    private var pauseButton: MenuItem? = null
-
-    /**
-     * Menu item to clear the queue.
-     */
-    private var clearButton: MenuItem? = null
-
     /**
      * Subscription list to be cleared during [onDestroyView].
      */
@@ -95,15 +81,15 @@ class DownloadFragment : BaseRxFragment<DownloadPresenter>() {
         recycler.setHasFixedSize(true)
 
         // Suscribe to changes
-        subscriptions += presenter.downloadManager.runningSubject
+        subscriptions += DownloadService.runningRelay
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe { onQueueStatusChange(it) }
 
-        subscriptions += presenter.getStatusObservable()
+        subscriptions += presenter.getDownloadStatusObservable()
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe { onStatusChange(it) }
 
-        subscriptions += presenter.getProgressObservable()
+        subscriptions += presenter.getDownloadProgressObservable()
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe { onUpdateDownloadedPages(it) }
     }
@@ -119,23 +105,17 @@ class DownloadFragment : BaseRxFragment<DownloadPresenter>() {
 
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
         inflater.inflate(R.menu.download_queue, menu)
+    }
 
+    override fun onPrepareOptionsMenu(menu: Menu) {
         // Set start button visibility.
-        startButton = menu.findItem(R.id.start_queue).apply {
-            isVisible = !isRunning && !presenter.downloadQueue.isEmpty()
-        }
+        menu.findItem(R.id.start_queue).isVisible = !isRunning && !presenter.downloadQueue.isEmpty()
 
         // Set pause button visibility.
-        pauseButton = menu.findItem(R.id.pause_queue).apply {
-            isVisible = isRunning
-        }
+        menu.findItem(R.id.pause_queue).isVisible = isRunning
 
         // Set clear button visibility.
-        clearButton = menu.findItem(R.id.clear_queue).apply {
-            if (!presenter.downloadQueue.isEmpty()) {
-                isVisible = true
-            }
-        }
+        menu.findItem(R.id.clear_queue).isVisible = !presenter.downloadQueue.isEmpty()
     }
 
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
@@ -182,7 +162,7 @@ class DownloadFragment : BaseRxFragment<DownloadPresenter>() {
                 // Get the sum of percentages for all the pages.
                 .flatMap {
                     Observable.from(download.pages)
-                            .map { it.progress }
+                            .map(Page::progress)
                             .reduce { x, y -> x + y }
                 }
                 // Keep only the latest emission to avoid backpressure.
@@ -218,9 +198,7 @@ class DownloadFragment : BaseRxFragment<DownloadPresenter>() {
      */
     private fun onQueueStatusChange(running: Boolean) {
         isRunning = running
-        startButton?.isVisible = !running && !presenter.downloadQueue.isEmpty()
-        pauseButton?.isVisible = running
-        clearButton?.isVisible = !presenter.downloadQueue.isEmpty()
+        activity.supportInvalidateOptionsMenu()
 
         // Check if download queue is empty and update information accordingly.
         setInformationView()
@@ -232,13 +210,11 @@ class DownloadFragment : BaseRxFragment<DownloadPresenter>() {
      * @param downloads the downloads from the queue.
      */
     fun onNextDownloads(downloads: List<Download>) {
+        activity.supportInvalidateOptionsMenu()
+        setInformationView()
         adapter.setItems(downloads)
     }
 
-    fun onDownloadRemoved(position: Int) {
-        adapter.notifyItemRemoved(position)
-    }
-
     /**
      * Called when the progress of a download changes.
      *

app/src/main/java/eu/kanade/tachiyomi/ui/download/DownloadPresenter.kt

@@ -29,36 +29,21 @@ class DownloadPresenter : BasePresenter<DownloadFragment>() {
 
     override fun onCreate(savedState: Bundle?) {
         super.onCreate(savedState)
-        
-        Observable.just(ArrayList(downloadQueue))
-                .doOnNext { syncQueue(it) }
-                .subscribeLatestCache({ view, downloads ->
-                    view.onNextDownloads(downloads)
-                }, { view, error ->
+
+        downloadQueue.getUpdatedObservable()
+                .observeOn(AndroidSchedulers.mainThread())
+                .map { ArrayList(it) }
+                .subscribeLatestCache(DownloadFragment::onNextDownloads, { view, error ->
                     Timber.e(error)
                 })
     }
 
-    private fun syncQueue(queue: MutableList<Download>) {
-        add(downloadQueue.getRemovedObservable()
-                .observeOn(AndroidSchedulers.mainThread())
-                .subscribe { download ->
-                    val position = queue.indexOf(download)
-                    if (position != -1) {
-                        queue.removeAt(position)
-
-                        @Suppress("DEPRECATION")
-                        view?.onDownloadRemoved(position)
-                    }
-                })
-    }
-
-    fun getStatusObservable(): Observable<Download> {
+    fun getDownloadStatusObservable(): Observable<Download> {
         return downloadQueue.getStatusObservable()
                 .startWith(downloadQueue.getActiveDownloads())
     }
 
-    fun getProgressObservable(): Observable<Download> {
+    fun getDownloadProgressObservable(): Observable<Download> {
         return downloadQueue.getProgressObservable()
                 .onBackpressureBuffer()
     }