From c9035b5df9a331dbed3322eb6ad95bc81d1d7f22 Mon Sep 17 00:00:00 2001
From: arkon <eugcheung94@gmail.com>
Date: Fri, 8 May 2020 18:41:27 -0400
Subject: [PATCH] Download from up to 5 different sources concurrently (closes
 #2534)

---
 .../eu/kanade/tachiyomi/data/download/Downloader.kt   | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt b/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt
index c6bc9a65a..ae47453eb 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/download/Downloader.kt
@@ -181,7 +181,16 @@ class Downloader(
         subscriptions.clear()
 
         subscriptions += downloadsRelay.concatMapIterable { it }
-            .concatMap { downloadChapter(it).subscribeOn(Schedulers.io()) }
+            // Concurrently download from 5 different sources
+            .groupBy { it.source }
+            .flatMap(
+                { bySource ->
+                    bySource.concatMap { download ->
+                        downloadChapter(download).subscribeOn(Schedulers.io())
+                    }
+                },
+                5
+            )
             .onBackpressureBuffer()
             .observeOn(AndroidSchedulers.mainThread())
             .subscribe(