Introduce new SpiderQueenWorker stub

app/src/main/java/com/hippo/ehviewer/spider/SpiderQueen.java

@@ -68,6 +68,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
 import eu.kanade.tachiyomi.ui.reader.loader.PageLoader;
+import kotlinx.coroutines.CoroutineScopeKt;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
 import okhttp3.Response;
@@ -131,6 +132,8 @@ public final class SpiderQueen implements Runnable {
     private volatile Thread mQueenThread;
     private ThreadPoolExecutor mWorkerPoolExecutor;
     private int mWorkerCount;
+
+    private SpiderQueenWorker mWorkerScope;
     private volatile int[] mPageStateArray;
     // For download, when it go to mPageStateArray.size(), done
     private volatile int mDownloadPage = -1;
@@ -149,6 +152,8 @@ public final class SpiderQueen implements Runnable {
             mDecodeIndexArray[i] = -1;
         }
 
+        mWorkerScope = new SpiderQueenWorker();
+
         mWorkerPoolExecutor = new ThreadPoolExecutor(mWorkerMaxCount, mWorkerMaxCount,
                 0, TimeUnit.SECONDS, new LinkedBlockingDeque<>(),
                 new PriorityThreadFactory(SpiderWorker.class.getSimpleName(), Process.THREAD_PRIORITY_BACKGROUND));
@@ -377,6 +382,9 @@ public final class SpiderQueen implements Runnable {
         synchronized (mWorkerLock) {
             mWorkerLock.notifyAll();
         }
+
+        CoroutineScopeKt.cancel(mWorkerScope, null);
+        mWorkerScope = null;
     }
 
     public int size() {

app/src/main/java/com/hippo/ehviewer/spider/SqiderQueenWorker.kt

@@ -0,0 +1,13 @@
+package com.hippo.ehviewer.spider
+
+import com.hippo.ehviewer.Settings
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlin.coroutines.CoroutineContext
+
+class SpiderQueenWorker : CoroutineScope {
+    private val maxParallelismSize = Settings.getMultiThreadDownload().coerceIn(1, 10)
+    override val coroutineContext: CoroutineContext
+        get() = Dispatchers.IO.limitedParallelism(maxParallelismSize) + SupervisorJob()
+}