Serviceless rewrite, part 1

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

app/src/main/java/com/wireguard/android/configStore/ConfigStore.java

@@ -0,0 +1,65 @@
+package com.wireguard.android.configStore;
+
+import com.wireguard.config.Config;
+
+import java.util.Set;
+
+import java9.util.concurrent.CompletionStage;
+
+/**
+ * Interface for persistent storage providers for WireGuard configurations.
+ */
+
+public interface ConfigStore {
+    /**
+     * Create a persistent tunnel, which must have a unique name within the persistent storage
+     * medium.
+     *
+     * @param name   The name of the tunnel to create.
+     * @param config Configuration for the new tunnel.
+     * @return A future completed when the tunnel and its configuration have been saved to
+     * persistent storage. This future encapsulates the configuration that was actually saved to
+     * persistent storage. This future will always be completed on the main thread.
+     */
+    CompletionStage<Config> create(final String name, final Config config);
+
+    /**
+     * Delete a persistent tunnel.
+     *
+     * @param name The name of the tunnel to delete.
+     * @return A future completed when the tunnel and its configuration have been deleted. This
+     * future will always be completed on the main thread.
+     */
+    CompletionStage<Void> delete(final String name);
+
+    /**
+     * Enumerate the names of tunnels present in persistent storage.
+     *
+     * @return A future completed when the set of present tunnel names is available. This future
+     * will always be completed on the main thread.
+     */
+    CompletionStage<Set<String>> enumerate();
+
+    /**
+     * Load the configuration for the tunnel given by {@code name}.
+     *
+     * @param name The identifier for the configuration in persistent storage (i.e. the name of the
+     *             tunnel).
+     * @return A future completed when an in-memory representation of the configuration is
+     * available. This future encapsulates the configuration loaded from persistent storage. This
+     * future will always be completed on the main thread.
+     */
+    CompletionStage<Config> load(final String name);
+
+    /**
+     * Save the configuration for an existing tunnel given by {@code name}.
+     *
+     * @param name   The identifier for the configuration in persistent storage (i.e. the name of
+     *               the tunnel).
+     * @param config An updated configuration object for the tunnel.
+     * @return A future completed when the configuration has been saved to persistent storage. This
+     * future encapsulates the configuration that was actually saved to persistent storage. This
+     * future will always be completed on the main thread.
+     */
+    CompletionStage<Config> save(final String name, final Config config);
+}

app/src/main/java/com/wireguard/android/configStore/FileConfigStore.java

@@ -0,0 +1,98 @@
+package com.wireguard.android.configStore;
+
+import android.content.Context;
+import android.util.Log;
+
+import com.wireguard.android.Application.ApplicationContext;
+import com.wireguard.android.util.AsyncWorker;
+import com.wireguard.config.Config;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Set;
+
+import java9.util.concurrent.CompletionStage;
+import java9.util.stream.Collectors;
+import java9.util.stream.Stream;
+
+/**
+ * Created by samuel on 12/28/17.
+ */
+
+public final class FileConfigStore implements ConfigStore {
+    private static final String TAG = FileConfigStore.class.getSimpleName();
+
+    private final AsyncWorker asyncWorker;
+    private final Context context;
+
+    public FileConfigStore(final AsyncWorker asyncWorker,
+                           @ApplicationContext final Context context) {
+        this.asyncWorker = asyncWorker;
+        this.context = context;
+    }
+
+    @Override
+    public CompletionStage<Config> create(final String name, final Config config) {
+        return asyncWorker.supplyAsync(() -> {
+            final File file = fileFor(name);
+            if (!file.createNewFile()) {
+                final String message = "Configuration file " + file.getName() + " already exists";
+                throw new IllegalStateException(message);
+            }
+            try (FileOutputStream stream = new FileOutputStream(file, false)) {
+                stream.write(config.toString().getBytes(StandardCharsets.UTF_8));
+                return config;
+            }
+        });
+    }
+
+    @Override
+    public CompletionStage<Void> delete(final String name) {
+        return asyncWorker.runAsync(() -> {
+            final File file = fileFor(name);
+            if (!file.delete())
+                throw new IOException("Cannot delete configuration file " + file.getName());
+        });
+    }
+
+    @Override
+    public CompletionStage<Set<String>> enumerate() {
+        return asyncWorker.supplyAsync(() -> Stream.of(context.fileList())
+                .filter(name -> name.endsWith(".conf"))
+                .map(name -> name.substring(0, name.length() - ".conf".length()))
+                .collect(Collectors.toUnmodifiableSet()));
+    }
+
+    private File fileFor(final String name) {
+        return new File(context.getFilesDir(), name + ".conf");
+    }
+
+    @Override
+    public CompletionStage<Config> load(final String name) {
+        return asyncWorker.supplyAsync(() -> {
+            try (FileInputStream stream = new FileInputStream(fileFor(name))) {
+                return Config.from(stream);
+            }
+        });
+    }
+
+    @Override
+    public CompletionStage<Config> save(final String name, final Config config) {
+        Log.d(TAG, "Requested save config for tunnel " + name);
+        return asyncWorker.supplyAsync(() -> {
+            final File file = fileFor(name);
+            if (!file.isFile()) {
+                final String message = "Configuration file " + file.getName() + " not found";
+                throw new IllegalStateException(message);
+            }
+            try (FileOutputStream stream = new FileOutputStream(file, false)) {
+                Log.d(TAG, "Writing out config for tunnel " + name);
+                stream.write(config.toString().getBytes(StandardCharsets.UTF_8));
+                return config;
+            }
+        });
+    }
+}