Android: Re-implement a subset of CompletableFuture

Imagine if Android phones actually got updates

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/main/MainPresenter.java

@@ -19,12 +19,12 @@
 import org.dolphinemu.dolphinemu.services.GameFileCacheService;
 import org.dolphinemu.dolphinemu.utils.AfterDirectoryInitializationRunner;
 import org.dolphinemu.dolphinemu.utils.BooleanSupplier;
+import org.dolphinemu.dolphinemu.utils.CompletableFuture;
 import org.dolphinemu.dolphinemu.utils.ContentHandler;
 import org.dolphinemu.dolphinemu.utils.FileBrowserHelper;
 import org.dolphinemu.dolphinemu.utils.WiiUtils;
 
 import java.util.Arrays;
-import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
 import java.util.function.Supplier;
 
@@ -171,9 +171,6 @@ public void installWAD(String path)
 
   public void importWiiSave(String path)
   {
-    if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.N)
-      return;  // TODO
-
     final Activity mainPresenterActivity = (Activity) mContext;
 
     CompletableFuture<Boolean> canOverwriteFuture = new CompletableFuture<>();

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/CompletableFuture.java

@@ -0,0 +1,95 @@
+package org.dolphinemu.dolphinemu.utils;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Simplified re-implementation of a subset of {@link java.util.concurrent.CompletableFuture}.
+ * Replace this class with that class once we have full Java 8 support (once we require API 24).
+ */
+public class CompletableFuture<T> implements Future<T>
+{
+  private final Lock lock = new ReentrantLock();
+  private final Condition done = lock.newCondition();
+
+  private boolean isDone = false;
+  private T result = null;
+
+  @Override
+  public boolean cancel(boolean mayInterruptIfRunning)
+  {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean isCancelled()
+  {
+    return false;
+  }
+
+  @Override
+  public boolean isDone()
+  {
+    return isDone;
+  }
+
+  @Override
+  public T get() throws ExecutionException, InterruptedException
+  {
+    lock.lock();
+    try
+    {
+      while (!isDone)
+        done.await();
+
+      return result;
+    }
+    finally
+    {
+      lock.unlock();
+    }
+  }
+
+  @Override
+  public T get(long timeout, TimeUnit unit)
+          throws ExecutionException, InterruptedException, TimeoutException
+  {
+    lock.lock();
+    try
+    {
+      while (!isDone)
+      {
+        if (!done.await(timeout, unit))
+          throw new TimeoutException();
+      }
+
+      return result;
+    }
+    finally
+    {
+      lock.unlock();
+    }
+  }
+
+  public boolean complete(T value)
+  {
+    lock.lock();
+    try
+    {
+      boolean wasDone = isDone;
+      result = value;
+      isDone = true;
+      done.signalAll();
+      return !wasDone;
+    }
+    finally
+    {
+      lock.unlock();
+    }
+  }
+}