Allow exporting to zip file

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/AndroidManifest.xml

@@ -5,7 +5,7 @@
     android:installLocation="internalOnly">
 
     <uses-permission android:name="android.permission.INTERNET" />
-    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
 
     <application

app/src/main/java/com/wireguard/android/activity/SettingsActivity.java

@@ -1,6 +1,7 @@
 package com.wireguard.android.activity;
 
 import android.app.Activity;
+import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.preference.Preference;
 import android.preference.PreferenceFragment;
@@ -9,11 +10,60 @@ import com.wireguard.android.Application;
 import com.wireguard.android.R;
 import com.wireguard.android.backend.WgQuickBackend;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+
 /**
  * Interface for changing application-global persistent settings.
  */
 
 public class SettingsActivity extends Activity {
+    @FunctionalInterface
+    public interface PermissionRequestCallback {
+        void done(String[] permissions, int[] grantResults);
+    }
+
+    private HashMap<Integer, PermissionRequestCallback> permissionRequestCallbacks = new HashMap<>();
+    private int permissionRequestCounter = 0;
+
+    public synchronized void ensurePermissions(String[] permissions, PermissionRequestCallback cb) {
+        /* TODO(MSF): since when porting to AppCompat, you'll be replacing checkSelfPermission
+         * and requestPermission with AppCompat.checkSelfPermission and AppCompat.requestPermission,
+         * you can remove this SDK_INT block entirely here, and count on the compat lib to do
+         * the right thing. */
+        if (android.os.Build.VERSION.SDK_INT < 23) {
+            int[] granted = new int[permissions.length];
+            Arrays.fill(granted, PackageManager.PERMISSION_GRANTED);
+            cb.done(permissions, granted);
+        } else {
+            List<String> needPermissions = new ArrayList<>(permissions.length);
+            for (final String permission : permissions) {
+                if (getApplicationContext().checkSelfPermission(permission) != PackageManager.PERMISSION_GRANTED)
+                    needPermissions.add(permission);
+            }
+            if (needPermissions.isEmpty()) {
+                int[] granted = new int[permissions.length];
+                Arrays.fill(granted, PackageManager.PERMISSION_GRANTED);
+                cb.done(permissions, granted);
+                return;
+            }
+            int idx = permissionRequestCounter++;
+            permissionRequestCallbacks.put(idx, cb);
+            requestPermissions(needPermissions.toArray(new String[needPermissions.size()]), idx);
+        }
+    }
+
+    @Override
+    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
+        final PermissionRequestCallback f = permissionRequestCallbacks.get(requestCode);
+        if (f != null) {
+            permissionRequestCallbacks.remove(requestCode);
+            f.done(permissions, grantResults);
+        }
+    }
+
     @Override
     protected void onCreate(final Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

app/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java

@@ -0,0 +1,123 @@
+package com.wireguard.android.preference;
+
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.os.Environment;
+import android.preference.Preference;
+import android.util.AttributeSet;
+import android.util.Log;
+
+import com.commonsware.cwac.crossport.design.widget.Snackbar;
+import com.wireguard.android.Application;
+import com.wireguard.android.Application.ApplicationComponent;
+import com.wireguard.android.R;
+import com.wireguard.android.activity.SettingsActivity;
+import com.wireguard.android.model.Tunnel;
+import com.wireguard.android.model.TunnelManager;
+import com.wireguard.android.util.AsyncWorker;
+import com.wireguard.android.util.ExceptionLoggers;
+import com.wireguard.config.Config;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+import java9.util.concurrent.CompletableFuture;
+
+/**
+ * Preference implementing a button that asynchronously exports config zips.
+ */
+
+public class ZipExporterPreference extends Preference {
+    private static final String TAG = "WireGuard/" + ZipExporterPreference.class.getSimpleName();
+
+    private final AsyncWorker asyncWorker;
+    private final TunnelManager tunnelManager;
+    private String exportedFilePath = null;
+
+    @SuppressWarnings({"SameParameterValue", "WeakerAccess"})
+    public ZipExporterPreference(final Context context, final AttributeSet attrs) {
+        super(context, attrs);
+        final ApplicationComponent applicationComponent = Application.getComponent();
+        asyncWorker = applicationComponent.getAsyncWorker();
+        tunnelManager = applicationComponent.getTunnelManager();
+    }
+
+    @Override
+    public CharSequence getSummary() {
+        if (exportedFilePath == null)
+            return getContext().getString(R.string.export_summary);
+        else
+            return getContext().getString(R.string.export_success, exportedFilePath);
+    }
+
+    @Override
+    public CharSequence getTitle() {
+        return getContext().getString(getTitleRes());
+    }
+
+    @Override
+    public int getTitleRes() {
+        return R.string.zip_exporter_title;
+    }
+
+    private void exportZip() {
+        List<Tunnel> tunnels = new ArrayList<>(tunnelManager.getTunnels());
+        List<CompletableFuture<Config>> futureConfigs = new ArrayList<>(tunnels.size());
+        for (final Tunnel tunnel : tunnels)
+            futureConfigs.add(tunnel.getConfigAsync().toCompletableFuture());
+        if (futureConfigs.isEmpty()) {
+            exportZipComplete(null, new IllegalArgumentException("No tunnels exist"));
+            return;
+        }
+        CompletableFuture.allOf(futureConfigs.toArray(new CompletableFuture[futureConfigs.size()]))
+                .whenComplete((ignored1, exception) -> {
+                    asyncWorker.supplyAsync(() -> {
+                        if (exception != null)
+                            throw exception;
+                        final File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
+                        final File file = new File(path, "wireguard-export.zip");
+                        try {
+                            path.mkdirs();
+                            final ZipOutputStream zip = new ZipOutputStream(new FileOutputStream(file));
+                            for (int i = 0; i < futureConfigs.size(); ++i) {
+                                zip.putNextEntry(new ZipEntry(tunnels.get(i).getName() + ".conf"));
+                                zip.write(futureConfigs.get(i).getNow(null).toString().getBytes(StandardCharsets.UTF_8));
+                            }
+                            zip.closeEntry();
+                            zip.close();
+                        } catch (Exception e) {
+                            file.delete();
+                            throw e;
+                        }
+                        return file.getAbsolutePath();
+                    }).whenComplete(this::exportZipComplete);
+                });
+    }
+
+    private void exportZipComplete(String filePath, Throwable throwable) {
+        if (throwable != null) {
+            final String error = ExceptionLoggers.unwrap(throwable).getMessage();
+            final String message = getContext().getString(R.string.export_error, error);
+            Log.e(TAG, message, throwable);
+            Snackbar.make(((SettingsActivity)getContext()).findViewById(android.R.id.content), message, Snackbar.LENGTH_LONG).show();
+        } else {
+            exportedFilePath = filePath;
+            setEnabled(false);
+            notifyChanged();
+        }
+    }
+
+    @Override
+    protected void onClick() {
+        ((SettingsActivity)getContext()).ensurePermissions(new String[] { "android.permission.WRITE_EXTERNAL_STORAGE" }, (permissions, granted) -> {
+            if (granted.length > 0 && granted[0] == PackageManager.PERMISSION_GRANTED)
+                exportZip();
+        });
+    }
+
+}

app/src/main/res/values/strings.xml

@@ -20,7 +20,7 @@
     <string name="config_save_success">Successfully saved configuration for “%s”</string>
     <string name="create_activity_title">Create WireGuard Tunnel</string>
     <string name="create_empty">Create from scratch</string>
-    <string name="create_from_file">Create from file</string>
+    <string name="create_from_file">Create from file or archive</string>
     <string name="delete">Delete</string>
     <string name="dns_servers">DNS servers</string>
     <string name="edit">Edit</string>
@@ -33,6 +33,10 @@
     <string name="hint_generated">(generated)</string>
     <string name="hint_optional">(optional)</string>
     <string name="hint_random">(random)</string>
+    <string name="zip_exporter_title">Export tunnels to zip file</string>
+    <string name="export_error">Unable to export tunnels: %s</string>
+    <string name="export_success">Saved to %s</string>
+    <string name="export_summary">Zip file will be saved to downloads folder</string>
     <string name="import_error">Unable to import tunnel: %s</string>
     <string name="import_success">Imported “%s”</string>
     <string name="import_total_success">Imported %d tunnels</string>

app/src/main/res/xml/preferences.xml

@@ -6,4 +6,5 @@
         android:summary="@string/restore_on_boot_summary"
         android:title="@string/restore_on_boot_title" />
     <com.wireguard.android.preference.ToolsInstallerPreference android:key="tools_installer" />
+    <com.wireguard.android.preference.ZipExporterPreference android:key="zip_exporter" />
 </PreferenceScreen>