Refactor: centralise download with sha1

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/modloaders/modpacks/api/ModDownloader.java

@@ -8,6 +8,7 @@ import net.kdt.pojavlaunch.utils.DownloadUtils;
 import java.io.File;
 import java.io.IOException;
 import java.io.InterruptedIOException;
+import java.util.concurrent.Callable;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
@@ -117,33 +118,22 @@ public class ModDownloader {
 
         @Override
         public void run() {
-            IOException exception = null;
             for(String sourceUrl : mDownloadUrls) {
                 try {
-                    int i=0;
+                    DownloadUtils.downloadFileEnsureSha1(mDestination, mSha1, (Callable<Void>) () -> {
-                    while (i < 5){
+                        IOException exception = tryDownload(sourceUrl);
-                        exception = tryDownload(sourceUrl);
-                        if(exception == null) {
-                            if(mSha1 != null && !Tools.compareSHA1(mDestination, mSha1)){
-                                // Remove the target file and retry
-                                i++;
-                                mDestination.delete();
-                                continue;
-                            }
-                            // No Sha or it matched
-                            break;
-                        }
-                        // If there is an exception, try another source
-                        break;
-                    }
 
-                }catch (InterruptedException e) {
+                        if(exception != null) {
+                            downloadFailed(exception);
+                        }
+
+                        return null;
+                    });
+
+                }catch (IOException e) {
                     return;
                 }
             }
-            if(exception != null) {
-                downloadFailed(exception);
-            }
         }
 
         private IOException tryDownload(String sourceUrl) throws InterruptedException {

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/modloaders/modpacks/api/ModpackInstaller.java

@@ -15,6 +15,7 @@ import net.kdt.pojavlaunch.value.launcherprofiles.MinecraftProfile;
 import java.io.File;
 import java.io.IOException;
 import java.util.Locale;
+import java.util.concurrent.Callable;
 
 public class ModpackInstaller {
 
@@ -30,13 +31,12 @@ public class ModpackInstaller {
         ModLoader modLoaderInfo;
         try {
             byte[] downloadBuffer = new byte[8192];
-            int attempt = 0;
+            DownloadUtils.downloadFileEnsureSha1(modpackFile, versionHash, (Callable<Void>) () -> {
-            while (attempt < 3 && (!modpackFile.exists() || !Tools.compareSHA1(modpackFile, versionHash))){
-                attempt++;
                 DownloadUtils.downloadFileMonitored(versionUrl, modpackFile, downloadBuffer,
                         new DownloaderProgressWrapper(R.string.modpack_download_downloading_metadata,
                                 ProgressLayout.INSTALL_MODPACK));
-            }
+                return null;
+            });
 
             // Install the modpack
             modLoaderInfo = installFunction.installModpack(modpackFile, new File(Tools.DIR_GAME_HOME, "custom_instances/"+modpackName));

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/utils/DownloadUtils.java

@@ -7,6 +7,8 @@ import androidx.annotation.Nullable;
 import java.io.*;
 import java.net.*;
 import java.nio.charset.*;
+import java.util.concurrent.Callable;
+
 import net.kdt.pojavlaunch.*;
 import org.apache.commons.io.*;
 
@@ -183,6 +185,35 @@ public class DownloadUtils {
         conn.disconnect();
     }
 
+    public static <T> T downloadFileEnsureSha1(File outputFile, @Nullable String sha1, Callable<T> downloadFunction) throws IOException {
+        // Skip if needed
+        if(sha1 == null){
+            try {
+                return downloadFunction.call();
+            } catch (IOException e){
+                throw e;
+            }
+            catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+        int attempts = 0;
+        T result = null;
+        while (attempts < 5 && (!outputFile.exists() || Tools.compareSHA1(outputFile, sha1))){
+            attempts++;
+            try {
+                result = downloadFunction.call();
+            } catch (IOException e){
+                throw e;
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+        }
+        return result;
+
+    }
+
     public interface ParseCallback<T> {
         T process(String input) throws ParseException;
     }