When importing, read the file from SAF on a background thread

Fixes issue with importing from Nextcloud. Close #673.

app/src/main/java/com/beemdevelopment/aegis/ui/ImportEntriesActivity.java

@@ -4,7 +4,6 @@ import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
 import android.content.pm.PackageManager;
-import android.net.Uri;
 import android.os.Bundle;
 import android.text.TextUtils;
 import android.view.Menu;
@@ -32,6 +31,8 @@ import com.beemdevelopment.aegis.vault.VaultManager;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.topjohnwu.superuser.Shell;
 
+import java.io.File;
+import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
@@ -78,19 +79,19 @@ public class ImportEntriesActivity extends AegisActivity {
         _fabScrollHelper = new FabScrollHelper(fab);
 
         Class<? extends DatabaseImporter> importerType = (Class<? extends DatabaseImporter>) getIntent().getSerializableExtra("importerType");
-        startImport(importerType, getIntent().getStringExtra("fileUri"));
+        startImport(importerType, (File) getIntent().getSerializableExtra("file"));
     }
 
-    private void startImport(@NonNull Class<? extends DatabaseImporter> importerType, @Nullable String fileUri) {
-        if (fileUri == null) {
+    private void startImport(@NonNull Class<? extends DatabaseImporter> importerType, @Nullable File file) {
+        if (file == null) {
             startImportApp(importerType);
         } else {
-            startImportFile(importerType, Uri.parse(fileUri));
+            startImportFile(importerType, file);
         }
     }
 
-    private void startImportFile(@NonNull Class<? extends DatabaseImporter> importerType, @NonNull Uri fileUri) {
-        try (InputStream stream = getContentResolver().openInputStream(fileUri)) {
+    private void startImportFile(@NonNull Class<? extends DatabaseImporter> importerType, @NonNull File file) {
+        try (InputStream stream = new FileInputStream(file)) {
             DatabaseImporter importer = DatabaseImporter.create(this, importerType);
             DatabaseImporter.State state = importer.read(stream);
             processImporterState(state);

app/src/main/java/com/beemdevelopment/aegis/ui/fragments/ImportExportPreferencesFragment.java

@@ -22,9 +22,10 @@ import com.beemdevelopment.aegis.BuildConfig;
 import com.beemdevelopment.aegis.R;
 import com.beemdevelopment.aegis.helpers.DropdownHelper;
 import com.beemdevelopment.aegis.importers.DatabaseImporter;
-import com.beemdevelopment.aegis.ui.dialogs.Dialogs;
 import com.beemdevelopment.aegis.ui.ImportEntriesActivity;
+import com.beemdevelopment.aegis.ui.dialogs.Dialogs;
 import com.beemdevelopment.aegis.ui.tasks.ExportTask;
+import com.beemdevelopment.aegis.ui.tasks.ImportFileTask;
 import com.beemdevelopment.aegis.vault.VaultBackupManager;
 import com.beemdevelopment.aegis.vault.VaultFileCredentials;
 import com.beemdevelopment.aegis.vault.VaultManager;
@@ -111,13 +112,20 @@ public class ImportExportPreferencesFragment extends PreferencesFragment {
             return;
         }
 
-        startImportEntriesActivity(_importerType, uri);
+        ImportFileTask task = new ImportFileTask(getContext(), result -> {
+            if (result.getException() == null) {
+                startImportEntriesActivity(_importerType, result.getFile());
+            } else {
+                Dialogs.showErrorDialog(getContext(), R.string.reading_file_error, result.getException());
+            }
+        });
+        task.execute(getLifecycle(), uri);
     }
 
-    private void startImportEntriesActivity(Class<? extends DatabaseImporter> importerType, Uri fileUri) {
+    private void startImportEntriesActivity(Class<? extends DatabaseImporter> importerType, File file) {
         Intent intent = new Intent(getActivity(), ImportEntriesActivity.class);
         intent.putExtra("importerType", importerType);
-        intent.putExtra("fileUri", fileUri == null ? null : fileUri.toString());
+        intent.putExtra("file", file);
         startActivityForResult(intent, CODE_IMPORT);
     }
 

app/src/main/java/com/beemdevelopment/aegis/ui/tasks/ImportFileTask.java

@@ -0,0 +1,69 @@
+package com.beemdevelopment.aegis.ui.tasks;
+
+import android.content.Context;
+import android.net.Uri;
+
+import com.beemdevelopment.aegis.R;
+import com.beemdevelopment.aegis.util.IOUtils;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * ImportFileTask reads an SAF file from a background thread and
+ * writes it to a temporary file in the cache directory.
+ */
+public class ImportFileTask extends ProgressDialogTask<Uri, ImportFileTask.Result> {
+    private final Callback _cb;
+
+    public ImportFileTask(Context context, Callback cb) {
+        super(context, context.getString(R.string.reading_file));
+        _cb = cb;
+    }
+
+    @Override
+    protected Result doInBackground(Uri... uris) {
+        Context context = getDialog().getContext();
+
+        try (InputStream inStream = context.getContentResolver().openInputStream(uris[0])) {
+            File tempFile = File.createTempFile("import-", "", context.getCacheDir());
+            try (FileOutputStream outStream = new FileOutputStream(tempFile)) {
+                IOUtils.copy(inStream, outStream);
+            }
+
+            return new Result(tempFile, null);
+        } catch (IOException e) {
+            return new Result(null, e);
+        }
+    }
+
+    @Override
+    protected void onPostExecute(Result result) {
+        super.onPostExecute(result);
+        _cb.onTaskFinished(result);
+    }
+
+    public interface Callback {
+        void onTaskFinished(Result result);
+    }
+
+    public static class Result {
+        private final File _file;
+        private final Exception _e;
+
+        public Result(File file, Exception e) {
+            _file = file;
+            _e = e;
+        }
+
+        public File getFile() {
+            return _file;
+        }
+
+        public Exception getException() {
+            return _e;
+        }
+    }
+}

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

@@ -148,6 +148,7 @@
     <string name="snackbar_authentication_method">Please select an authentication method</string>
     <string name="encrypting_vault">Encrypting the vault</string>
     <string name="exporting_vault">Exporting the vault</string>
+    <string name="reading_file">Reading file</string>
     <string name="delete_entry">Delete entry</string>
     <string name="delete_entry_description">Are you sure you want to delete this entry?</string>
     <string name="delete_entry_explanation">This action does not disable 2FA for <b>%s</b>. To prevent losing access, make sure that you have disabled 2FA or that you have an alternative way to generate codes for this service.</string>