Serviceless rewrite, part 1

Signed-off-by: Samuel Holland <samuel@sholland.org>

1 files changed, 65 insertions, 0 deletions

diff --git a/app/src/main/java/com/wireguard/android/util/AsyncWorker.java b/app/src/main/java/com/wireguard/android/util/AsyncWorker.java
new file mode 100644
index 00000000..5f9f0a83
--- /dev/null
+++ b/app/src/main/java/com/wireguard/android/util/AsyncWorker.java
@@ -0,0 +1,65 @@
+package com.wireguard.android.util;
+
+import android.os.Handler;
+
+import com.wireguard.android.Application.ApplicationHandler;
+import com.wireguard.android.Application.ApplicationScope;
+
+import java.util.concurrent.Executor;
+
+import javax.inject.Inject;
+
+import java9.util.concurrent.CompletableFuture;
+import java9.util.concurrent.CompletionStage;
+
+/**
+ * Helper class for running asynchronous tasks and ensuring they are completed on the main thread.
+ */
+
+@ApplicationScope
+public class AsyncWorker {
+    private final Executor executor;
+    private final Handler handler;
+
+    @Inject
+    public AsyncWorker(final Executor executor, @ApplicationHandler final Handler handler) {
+        this.executor = executor;
+        this.handler = handler;
+    }
+
+    public CompletionStage<Void> runAsync(final AsyncRunnable<?> runnable) {
+        final CompletableFuture<Void> future = new CompletableFuture<>();
+        executor.execute(() -> {
+            try {
+                runnable.run();
+                handler.post(() -> future.complete(null));
+            } catch (final Throwable t) {
+                handler.post(() -> future.completeExceptionally(t));
+            }
+        });
+        return future;
+    }
+
+    public <T> CompletionStage<T> supplyAsync(final AsyncSupplier<T, ?> supplier) {
+        final CompletableFuture<T> future = new CompletableFuture<>();
+        executor.execute(() -> {
+            try {
+                final T result = supplier.get();
+                handler.post(() -> future.complete(result));
+            } catch (final Throwable t) {
+                handler.post(() -> future.completeExceptionally(t));
+            }
+        });
+        return future;
+    }
+
+    @FunctionalInterface
+    public interface AsyncRunnable<E extends Throwable> {
+        void run() throws E;
+    }
+
+    @FunctionalInterface
+    public interface AsyncSupplier<T, E extends Throwable> {
+        T get() throws E;
+    }
+}