Add support for specific toasts when backup restoration cannot proceed.

Fixes #10918

app/src/main/java/org/thoughtcrime/securesms/registration/fragments/RestoreBackupFragment.java

@@ -26,6 +26,7 @@ import androidx.annotation.MainThread;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
+import androidx.annotation.StringRes;
 import androidx.appcompat.app.AlertDialog;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.navigation.Navigation;
@@ -37,6 +38,7 @@ import net.zetetic.database.sqlcipher.SQLiteDatabase;
 import org.greenrobot.eventbus.EventBus;
 import org.greenrobot.eventbus.Subscribe;
 import org.greenrobot.eventbus.ThreadMode;
+import org.signal.core.util.ThreadUtil;
 import org.signal.core.util.logging.Log;
 import org.thoughtcrime.securesms.AppInitialization;
 import org.thoughtcrime.securesms.LoggingFragment;
@@ -216,10 +218,36 @@ public final class RestoreBackupFragment extends LoggingFragment {
                          @NonNull Uri backupUri,
                          @NonNull OnBackupSearchResultListener listener)
   {
-    SimpleTask.run(() -> BackupUtil.getBackupInfoFromSingleUri(context, backupUri),
+    SimpleTask.run(() -> {
+                     try {
+                       return BackupUtil.getBackupInfoFromSingleUri(context, backupUri);
+                     } catch (BackupUtil.BackupFileException e) {
+                       Log.w(TAG, "Could not restore backup.", e);
+                       postToastForBackupRestorationFailure(context, e);
+                       return null;
+                     }
+                   },
                    listener::run);
   }
 
+  private static void postToastForBackupRestorationFailure(@NonNull Context context, @NonNull BackupUtil.BackupFileException exception) {
+    final @StringRes int errorResId;
+    switch (exception.getState()) {
+      case READABLE:
+        throw new AssertionError("Unexpected error state.");
+      case NOT_FOUND:
+        errorResId = R.string.RestoreBackupFragment__backup_not_found;
+        break;
+      case UNSUPPORTED_FILE_EXTENSION:
+        errorResId = R.string.RestoreBackupFragment__backup_has_a_bad_extension;
+        break;
+      default:
+        errorResId = R.string.RestoreBackupFragment__backup_could_not_be_read;
+    }
+
+    ThreadUtil.postToMain(() -> Toast.makeText(context, errorResId, Toast.LENGTH_LONG).show());
+  }
+
   private void handleRestore(@NonNull Context context, @NonNull BackupUtil.BackupInfo backup) {
     View     view   = LayoutInflater.from(context).inflate(R.layout.enter_backup_passphrase_dialog, null);
     EditText prompt = view.findViewById(R.id.restore_passphrase_input);

app/src/main/java/org/thoughtcrime/securesms/util/BackupUtil.java

@@ -6,11 +6,11 @@ import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Build;
-import android.text.TextUtils;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
+import androidx.annotation.VisibleForTesting;
 import androidx.documentfile.provider.DocumentFile;
 
 import org.signal.core.util.logging.Log;
@@ -166,14 +166,22 @@ public class BackupUtil {
     return backups;
   }
 
-  public static @Nullable BackupInfo getBackupInfoFromSingleUri(@NonNull Context context, @NonNull Uri singleUri) {
-    DocumentFile documentFile = DocumentFile.fromSingleUri(context, singleUri);
+  public static @Nullable BackupInfo getBackupInfoFromSingleUri(@NonNull Context context, @NonNull Uri singleUri) throws BackupFileException {
+    DocumentFile documentFile = Objects.requireNonNull(DocumentFile.fromSingleUri(context, singleUri));
 
-    if (isBackupFileReadable(documentFile)) {
+    return getBackupInfoFromSingleDocumentFile(documentFile);
+  }
+
+  @VisibleForTesting
+  static @Nullable BackupInfo getBackupInfoFromSingleDocumentFile(@NonNull DocumentFile documentFile) throws BackupFileException {
+    BackupFileState backupFileState = getBackupFileState(documentFile);
+
+    if (backupFileState.isSuccess()) {
       long backupTimestamp = getBackupTimestamp(Objects.requireNonNull(documentFile.getName()));
       return new BackupInfo(backupTimestamp, documentFile.length(), documentFile.getUri());
     } else {
       Log.w(TAG, "Could not load backup info.");
+      backupFileState.throwIfError();
       return null;
     }
   }
@@ -258,21 +266,58 @@ public class BackupUtil {
     return -1;
   }
 
-  private static boolean isBackupFileReadable(@Nullable DocumentFile documentFile) {
-    if (documentFile == null) {
-      throw new AssertionError("We do not support platforms prior to KitKat.");
-    } else if (!documentFile.exists()) {
-      Log.w(TAG, "isBackupFileReadable: The document at the specified Uri cannot be found.");
-      return false;
+  private static BackupFileState getBackupFileState(@NonNull DocumentFile documentFile) {
+    if (!documentFile.exists()) {
+      return BackupFileState.NOT_FOUND;
     } else if (!documentFile.canRead()) {
-      Log.w(TAG, "isBackupFileReadable: The document at the specified Uri cannot be read.");
-      return false;
-    } else if (TextUtils.isEmpty(documentFile.getName()) || !documentFile.getName().endsWith(".backup")) {
-      Log.w(TAG, "isBackupFileReadable: The document at the specified Uri has an unsupported file extension.");
-      return false;
+      return BackupFileState.NOT_READABLE;
+    } else if (Util.isEmpty(documentFile.getName()) || !documentFile.getName().endsWith(".backup")) {
+      return BackupFileState.UNSUPPORTED_FILE_EXTENSION;
     } else {
-      Log.i(TAG, "isBackupFileReadable: The document at the specified Uri looks like a readable backup");
-      return true;
+      return BackupFileState.READABLE;
+    }
+  }
+
+  /**
+   * Describes the validity of a backup file.
+   */
+  public enum BackupFileState {
+    READABLE("The document at the specified Uri looks like a readable backup."),
+    NOT_FOUND("The document at the specified Uri cannot be found."),
+    NOT_READABLE("The document at the specified Uri cannot be read."),
+    UNSUPPORTED_FILE_EXTENSION("The document at the specified Uri has an unsupported file extension.");
+
+    private final String message;
+
+    BackupFileState(String message) {
+      this.message = message;
+    }
+
+    public boolean isSuccess() {
+      return this == READABLE;
+    }
+
+    public void throwIfError() throws BackupFileException {
+      if (!isSuccess()) {
+        throw new BackupFileException(this);
+      }
+    }
+  }
+
+  /**
+   * Wrapping exception for a non-successful BackupFileState.
+   */
+  public static class BackupFileException extends Exception {
+
+    private final BackupFileState state;
+
+    BackupFileException(BackupFileState backupFileState) {
+      super(backupFileState.message);
+      this.state = backupFileState;
+    }
+
+    public @NonNull BackupFileState getState() {
+      return state;
     }
   }
 

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

@@ -471,6 +471,12 @@
     <string name="RestoreBackupFragment__to_continue_using_backups_please_choose_a_folder">To continue using backups, please choose a folder. New backups will be saved to this location.</string>
     <string name="RestoreBackupFragment__choose_folder">Choose folder</string>
     <string name="RestoreBackupFragment__not_now">Not now</string>
+    <!-- Couldn't find the selected backup -->
+    <string name="RestoreBackupFragment__backup_not_found">Backup not found.</string>
+    <!-- Couldn't read the selected backup -->
+    <string name="RestoreBackupFragment__backup_could_not_be_read">Backup could not be read.</string>
+    <!-- Backup has an unsupported file extension -->
+    <string name="RestoreBackupFragment__backup_has_a_bad_extension">Backup has a bad extension.</string>
 
     <!-- BackupsPreferenceFragment -->
     <string name="BackupsPreferenceFragment__chat_backups">Chat backups</string>

app/src/test/java/org/thoughtcrime/securesms/util/BackupUtilTest.kt

@@ -0,0 +1,84 @@
+package org.thoughtcrime.securesms.util
+
+import androidx.documentfile.provider.DocumentFile
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.fail
+import org.junit.BeforeClass
+import org.junit.Test
+import org.mockito.Mockito.doReturn
+import org.mockito.Mockito.mock
+import org.signal.core.util.logging.Log
+import org.thoughtcrime.securesms.testutil.EmptyLogger
+
+class BackupUtilTest {
+
+  companion object {
+    private const val TEST_NAME = "1920837192.backup"
+
+    @BeforeClass
+    @JvmStatic
+    fun setUpClass() {
+      Log.initialize(EmptyLogger())
+    }
+  }
+
+  private val documentFile = mock(DocumentFile::class.java)
+
+  @Test
+  fun `Given a non-existent uri, when I getBackupInfoFromSingleDocumentFile, then I expect NOT_FOUND`() {
+    try {
+      BackupUtil.getBackupInfoFromSingleDocumentFile(documentFile)
+      fail("Expected a BackupFileException")
+    } catch (e: BackupUtil.BackupFileException) {
+      assertEquals(BackupUtil.BackupFileState.NOT_FOUND, e.state)
+    }
+  }
+
+  @Test
+  fun `Given an existent but unreadable uri, when I getBackupInfoFromSingleDocumentFile, then I expect NOT_READABLE`() {
+    givenFileExists()
+
+    try {
+      BackupUtil.getBackupInfoFromSingleDocumentFile(documentFile)
+      fail("Expected a BackupFileException")
+    } catch (e: BackupUtil.BackupFileException) {
+      assertEquals(BackupUtil.BackupFileState.NOT_READABLE, e.state)
+    }
+  }
+
+  @Test
+  fun `Given an existent readable uri with a bad extension, when I getBackupInfoFromSingleDocumentFile, then I expect UNSUPPORTED_FILE_EXTENSION`() {
+    givenFileExists()
+    givenFileIsReadable()
+
+    try {
+      BackupUtil.getBackupInfoFromSingleDocumentFile(documentFile)
+      fail("Expected a BackupFileException")
+    } catch (e: BackupUtil.BackupFileException) {
+      assertEquals(BackupUtil.BackupFileState.UNSUPPORTED_FILE_EXTENSION, e.state)
+    }
+  }
+
+  @Test
+  fun `Given an existent readable uri, when I getBackupInfoFromSingleDocumentFile, then I expect an info`() {
+    givenFileExists()
+    givenFileIsReadable()
+    givenFileHasCorrectExtension()
+
+    val info = BackupUtil.getBackupInfoFromSingleDocumentFile(documentFile)
+    assertNotNull(info)
+  }
+
+  private fun givenFileExists() {
+    doReturn(true).`when`(documentFile).exists()
+  }
+
+  private fun givenFileIsReadable() {
+    doReturn(true).`when`(documentFile).canRead()
+  }
+
+  private fun givenFileHasCorrectExtension() {
+    doReturn(TEST_NAME).`when`(documentFile).name
+  }
+}