[android] Address first round of review comments for attachments

briar-android/src/main/java/org/briarproject/briar/android/attachment/AttachmentCreationTask.java

@@ -37,7 +37,7 @@ class AttachmentCreationTask {
 	private final List<Uri> uris;
 	private final boolean needsSize;
 	@Nullable
-	private AttachmentCreator attachmentCreator;
+	private volatile AttachmentCreator attachmentCreator;
 
 	private volatile boolean canceled = false;
 
@@ -61,9 +61,10 @@ class AttachmentCreationTask {
 	@IoExecutor
 	public void storeAttachments() {
 		for (Uri uri: uris) processUri(uri);
+		AttachmentCreator attachmentCreator = this.attachmentCreator;
 		if (!canceled && attachmentCreator != null)
 			attachmentCreator.onAttachmentCreationFinished();
-		attachmentCreator = null;
+		this.attachmentCreator = null;
 	}
 
 	@IoExecutor
@@ -71,16 +72,17 @@ class AttachmentCreationTask {
 		if (canceled) return;
 		try {
 			AttachmentHeader h = storeAttachment(uri);
+			AttachmentCreator attachmentCreator = this.attachmentCreator;
 			if (attachmentCreator != null) {
-				attachmentCreator
-						.onAttachmentHeaderReceived(uri, h, needsSize);
+				attachmentCreator.onAttachmentHeaderReceived(uri, h, needsSize);
 			}
 		} catch (DbException | IOException e) {
 			logException(LOG, WARNING, e);
+			AttachmentCreator attachmentCreator = this.attachmentCreator;
 			if (attachmentCreator != null) {
 				attachmentCreator.onAttachmentError(uri, e);
-				canceled = true;
 			}
+			canceled = true;
 		}
 	}
 
@@ -90,9 +92,10 @@ class AttachmentCreationTask {
 		long start = now();
 		String contentType = contentResolver.getType(uri);
 		if (contentType == null) throw new IOException("null content type");
-		if (!isValidMimeType(contentType))
-			throw new UnsupportedMimeTypeException("", contentType,
-					uri.toString());
+		if (!isValidMimeType(contentType)) {
+			String uriString = uri.toString();
+			throw new UnsupportedMimeTypeException("", contentType, uriString);
+		}
 		InputStream is = contentResolver.openInputStream(uri);
 		if (is == null) throw new IOException();
 		long timestamp = System.currentTimeMillis();

briar-android/src/main/java/org/briarproject/briar/android/attachment/AttachmentCreator.java

@@ -44,7 +44,7 @@ public class AttachmentCreator {
 	@IoExecutor
 	private final Executor ioExecutor;
 	private final MessagingManager messagingManager;
-	private final AttachmentRetriever controller;
+	private final AttachmentRetriever retriever;
 
 	private final Map<Uri, AttachmentItem> unsentItems =
 			new ConcurrentHashMap<>();
@@ -57,12 +57,11 @@ public class AttachmentCreator {
 	private AttachmentCreationTask task;
 
 	public AttachmentCreator(Application app, @IoExecutor Executor ioExecutor,
-			MessagingManager messagingManager,
-			AttachmentRetriever controller) {
+			MessagingManager messagingManager, AttachmentRetriever retriever) {
 		this.app = app;
 		this.ioExecutor = ioExecutor;
 		this.messagingManager = messagingManager;
-		this.controller = controller;
+		this.retriever = retriever;
 	}
 
 	@UiThread
@@ -101,8 +100,8 @@ public class AttachmentCreator {
 			boolean needsSize) {
 		// get and cache AttachmentItem for ImagePreview
 		try {
-			Attachment a = controller.getMessageAttachment(h);
-			AttachmentItem item = controller.getAttachmentItem(h, a, needsSize);
+			Attachment a = retriever.getMessageAttachment(h);
+			AttachmentItem item = retriever.getAttachmentItem(h, a, needsSize);
 			if (item.hasError()) throw new IOException();
 			unsentItems.put(uri, item);
 			MutableLiveData<AttachmentItemResult> result =
@@ -156,7 +155,7 @@ public class AttachmentCreator {
 	 * @param id The MessageId of the sent message.
 	 */
 	public void onAttachmentsSent(MessageId id) {
-		controller.cachePut(id, new ArrayList<>(unsentItems.values()));
+		retriever.cachePut(id, new ArrayList<>(unsentItems.values()));
 		resetState();
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/attachment/AttachmentManager.java

@@ -9,7 +9,7 @@ import java.util.Collection;
 import java.util.List;
 
 @UiThread
-public interface AttachmentManager{
+public interface AttachmentManager {
 
 	AttachmentResult storeAttachments(Collection<Uri> uri);
 

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

@@ -138,6 +138,16 @@ public class TextAttachmentController extends TextSendController
 		return intent;
 	}
 
+	/**
+	 * This is called with the result Intent
+	 * returned by the Activity started with {@link #getAttachFileIntent()}.
+	 * <p>
+	 * This method must be called at most once per call to
+	 * {@link AttachImageListener#onAttachImage(Intent)}.
+	 * Normally, this is true if called from
+	 * {@link Activity#onActivityResult(int, int, Intent)} since this is called
+	 * at most once per call to {@link Activity#startActivityForResult(Intent, int)}.
+	 */
 	public void onImageReceived(@Nullable Intent resultData) {
 		if (resultData == null) return;
 		if (loadingUris || !imageUris.isEmpty()) throw new AssertionError();