Reject attachments that exceed the allowed size

Closes #1468

briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentResult.java

@@ -0,0 +1,43 @@
+package org.briarproject.briar.android.conversation;
+
+import android.net.Uri;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class AttachmentResult {
+
+	@Nullable
+	private final Uri uri;
+	@Nullable
+	private final String errorMsg;
+
+	public AttachmentResult(Uri uri) {
+		this.uri = uri;
+		this.errorMsg = null;
+	}
+
+	public AttachmentResult(@Nullable String errorMsg) {
+		this.uri = null;
+		this.errorMsg = errorMsg;
+	}
+
+	@Nullable
+	public Uri getUri() {
+		return uri;
+	}
+
+	public boolean isError() {
+		return errorMsg != null;
+	}
+
+	@Nullable
+	public String getErrorMsg() {
+		return errorMsg;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationViewModel.java

@@ -27,11 +27,13 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.briar.R;
 import org.briarproject.briar.android.util.UiUtils;
 import org.briarproject.briar.android.view.TextAttachmentController.AttachmentManager;
 import org.briarproject.briar.android.viewmodel.LiveEvent;
 import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
 import org.briarproject.briar.api.messaging.AttachmentHeader;
+import org.briarproject.briar.api.messaging.FileTooBigException;
 import org.briarproject.briar.api.messaging.MessagingManager;
 import org.briarproject.briar.api.messaging.PrivateMessage;
 import org.briarproject.briar.api.messaging.PrivateMessageFactory;
@@ -54,6 +56,7 @@ import static org.briarproject.bramble.util.LogUtils.now;
 import static org.briarproject.briar.android.conversation.AttachmentDimensions.getAttachmentDimensions;
 import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
 import static org.briarproject.briar.android.util.UiUtils.observeForeverOnce;
+import static org.briarproject.briar.api.messaging.MessagingConstants.MAX_IMAGE_SIZE;
 
 @NotNullByDefault
 public class ConversationViewModel extends AndroidViewModel implements
@@ -192,9 +195,11 @@ public class ConversationViewModel extends AndroidViewModel implements
 	}
 
 	@Override
-	public void storeAttachment(Uri uri, boolean needsSize, Runnable onSuccess,
-			Runnable onError) {
+	public LiveData<AttachmentResult> storeAttachment(Uri uri,
+			boolean needsSize) {
 		if (messagingGroupId.getValue() == null) loadGroupId();
+		// use LiveData to not keep references to view scope
+		MutableLiveData<AttachmentResult> result = new MutableLiveData<>();
 		observeForeverOnce(messagingGroupId, groupId -> dbExecutor.execute(()
 				-> {
 			if (groupId == null) throw new IllegalStateException();
@@ -204,13 +209,20 @@ public class ConversationViewModel extends AndroidViewModel implements
 						getApplication().getContentResolver();
 				attachmentController.createAttachmentHeader(contentResolver,
 						groupId, uri, needsSize);
-				androidExecutor.runOnUiThread(onSuccess);
+				result.postValue(new AttachmentResult(uri));
+			} catch(FileTooBigException e) {
+				logException(LOG, WARNING, e);
+				int mb = MAX_IMAGE_SIZE / 1024 / 1024;
+				String errorMsg = getApplication()
+						.getString(R.string.image_attach_error_too_big, mb);
+				result.postValue(new AttachmentResult(errorMsg));
 			} catch (DbException | IOException e) {
 				logException(LOG, WARNING, e);
-				androidExecutor.runOnUiThread(onError);
+				result.postValue(new AttachmentResult((String) null));
 			}
 			logDuration(LOG, "Storing attachment", start);
 		}));
+		return result;
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/view/ImagePreviewItem.java

@@ -15,7 +15,7 @@ class ImagePreviewItem {
 	private final Uri uri;
 	private boolean waitForLoading = true;
 
-	private ImagePreviewItem(Uri uri) {
+	ImagePreviewItem(Uri uri) {
 		this.uri = uri;
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/view/TextAttachmentController.java

@@ -1,6 +1,8 @@
 package org.briarproject.briar.android.view;
 
 import android.app.Activity;
+import android.arch.lifecycle.LifecycleOwner;
+import android.arch.lifecycle.LiveData;
 import android.content.ClipData;
 import android.content.Context;
 import android.content.Intent;
@@ -15,6 +17,7 @@ import android.widget.Toast;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.R;
+import org.briarproject.briar.android.conversation.AttachmentResult;
 import org.briarproject.briar.android.view.ImagePreview.ImagePreviewListener;
 import org.briarproject.briar.api.messaging.AttachmentHeader;
 
@@ -149,9 +152,17 @@ public class TextAttachmentController extends TextSendController
 		// store attachments and show preview when successful
 		boolean needsSize = items.size() == 1;
 		for (ImagePreviewItem item : items) {
-			attachmentManager.storeAttachment(item.getUri(), needsSize,
-					() -> imagePreview.loadPreviewImage(item),
-					this::onError);
+			attachmentManager.storeAttachment(item.getUri(), needsSize)
+					.observe(imageListener, this::onAttachmentResultReceived);
+		}
+	}
+
+	private void onAttachmentResultReceived(AttachmentResult result) {
+		if (result.isError() || result.getUri() == null) {
+			onError(result.getErrorMsg());
+		} else {
+			ImagePreviewItem item = new ImagePreviewItem(result.getUri());
+			imagePreview.loadPreviewImage(item);
 		}
 	}
 
@@ -194,8 +205,16 @@ public class TextAttachmentController extends TextSendController
 
 	@Override
 	public void onError() {
-		Toast.makeText(textInput.getContext(), R.string.image_attach_error,
-				LENGTH_LONG).show();
+		onError(null);
+	}
+
+	@UiThread
+	private void onError(@Nullable String errorMsg) {
+		if (errorMsg == null) {
+			errorMsg = imagePreview.getContext()
+					.getString(R.string.image_attach_error);
+		}
+		Toast.makeText(textInput.getContext(), errorMsg, LENGTH_LONG).show();
 		onCancel();
 	}
 
@@ -268,7 +287,7 @@ public class TextAttachmentController extends TextSendController
 				};
 	}
 
-	public interface AttachImageListener {
+	public interface AttachImageListener extends LifecycleOwner {
 		void onAttachImage(Intent intent);
 	}
 
@@ -277,11 +296,10 @@ public class TextAttachmentController extends TextSendController
 		 * Stores a new attachment in the database.
 		 *
 		 * @param uri The Uri of the attachment to store.
-		 * @param onSuccess will be run on the UiThread when the attachment was stored successfully.
-		 * @param onError will be run on the UiThread when the attachment could not be stored.
+		 * @param needsSize true if this is the only image in the message
+		 * and therefore needs to know its size.
 		 */
-		void storeAttachment(Uri uri, boolean needsSize, Runnable onSuccess,
-				Runnable onError);
+		LiveData<AttachmentResult> storeAttachment(Uri uri, boolean needsSize);
 
 		List<AttachmentHeader> getAttachmentHeaders();