Implement #612

app/src/main/java/com/hippo/ehviewer/gallery/ArchivePageLoader.java

@@ -41,6 +41,7 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.Stack;
@@ -187,6 +188,11 @@ public class ArchivePageLoader extends PageLoader2 {
         return dst;
     }
 
+    @Override
+    protected void preloadPages(@NonNull List<Integer> pages) {
+
+    }
+
     private class ArchiveHostTask implements Runnable {
         public final Thread[] archiveThreads = new Thread[]{
                 new Thread(new ArchiveTask()),

app/src/main/java/com/hippo/ehviewer/gallery/EhPageLoader.java

@@ -25,6 +25,7 @@ import com.hippo.image.Image;
 import com.hippo.unifile.UniFile;
 import com.hippo.yorozuya.SimpleHandler;
 
+import java.util.List;
 import java.util.Locale;
 
 import eu.kanade.tachiyomi.ui.reader.loader.PageLoader;
@@ -207,6 +208,13 @@ public class EhPageLoader extends PageLoader2 implements SpiderQueen.OnSpiderLis
         notifyPageFailed(index);
     }
 
+    @Override
+    protected void preloadPages(@NonNull List<Integer> pages) {
+        if (mSpiderQueen != null) {
+            mSpiderQueen.preloadPages(pages);
+        }
+    }
+
     private static class ReleaseTask implements Runnable {
 
         private SpiderQueen mSpiderQueen;

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

@@ -460,6 +460,19 @@ public final class SpiderQueen implements Runnable {
         }
     }
 
+    public void preloadPages(@NonNull List<Integer> pages) {
+        if (mQueenThread == null) {
+            return;
+        }
+
+        synchronized (mRequestPageQueue) {
+            pages.removeAll(mRequestPageQueue);
+            pages.removeAll(mRequestPageQueue2);
+            pages.removeAll(mDecodeRequestQueue);
+            mRequestPageQueue2.addAll(pages);
+        }
+    }
+
     /**
      * @return String for error<br>
      * Float for download percent<br>

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

@@ -17,6 +17,8 @@ abstract class PageLoader {
         (0 until size()).map { ReaderPage(it) }
     }
 
+    private val mPreloads = MathUtils.clamp(com.hippo.ehviewer.Settings.getPreloadImage(), 0, 100)
+
     var state = MutableStateFlow(STATE_WAIT)
 
     abstract val error: String
@@ -41,12 +43,19 @@ abstract class PageLoader {
             notifyPageSucceed(index, image)
         else
             onRequest(index)
+
+        // val pagesAbsent = (index until (mPreloads + index).coerceAtMost(size())).toMutableList().removeAll(mImageCache.snapshot().keys)
+        // Should we refresh our LruCache ?
+        val pagesAbsent = (index until (mPreloads + index).coerceAtMost(size())).mapNotNull { it.takeIf { mImageCache[it] == null } }
+        preloadPages(pagesAbsent)
     }
 
     fun retryPage(page: ReaderPage) {
         onForceRequest(mPages.indexOf(page))
     }
 
+    protected abstract fun preloadPages(pages: List<Int>)
+
     protected abstract fun onRequest(index: Int)
 
     protected abstract fun onForceRequest(index: Int)