Centralize attachment loading in AttachmentReader

This is needed so Glide can load attachments from the DB by using the same AttachmentHeader class.

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarDataFetcher.java

@@ -4,12 +4,13 @@ import com.bumptech.glide.Priority;
 import com.bumptech.glide.load.DataSource;
 import com.bumptech.glide.load.data.DataFetcher;
 
+import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.android.attachment.AttachmentItem;
 import org.briarproject.briar.api.media.Attachment;
-import org.briarproject.briar.api.messaging.MessagingManager;
+import org.briarproject.briar.media.AttachmentReader;
 
 import java.io.InputStream;
 import java.util.concurrent.Executor;
@@ -30,7 +31,7 @@ class BriarDataFetcher implements DataFetcher<InputStream> {
 	private final static Logger LOG =
 			getLogger(BriarDataFetcher.class.getName());
 
-	private final MessagingManager messagingManager;
+	private final ClientHelper clientHelper;
 	@DatabaseExecutor
 	private final Executor dbExecutor;
 	private final AttachmentItem attachment;
@@ -40,9 +41,9 @@ class BriarDataFetcher implements DataFetcher<InputStream> {
 	private volatile boolean cancel = false;
 
 	@Inject
-	BriarDataFetcher(MessagingManager messagingManager,
+	BriarDataFetcher(ClientHelper clientHelper,
 			@DatabaseExecutor Executor dbExecutor, AttachmentItem attachment) {
-		this.messagingManager = messagingManager;
+		this.clientHelper = clientHelper;
 		this.dbExecutor = dbExecutor;
 		this.attachment = attachment;
 	}
@@ -53,8 +54,8 @@ class BriarDataFetcher implements DataFetcher<InputStream> {
 		dbExecutor.execute(() -> {
 			if (cancel) return;
 			try {
-				Attachment a =
-						messagingManager.getAttachment(attachment.getHeader());
+				Attachment a = AttachmentReader
+						.getAttachment(clientHelper, attachment.getHeader());
 				inputStream = a.getStream();
 				callback.onDataReady(inputStream);
 			} catch (DbException e) {

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarDataFetcherFactory.java

@@ -1,9 +1,9 @@
 package org.briarproject.briar.android.conversation.glide;
 
+import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.android.attachment.AttachmentItem;
-import org.briarproject.briar.api.messaging.MessagingManager;
 
 import java.util.concurrent.Executor;
 
@@ -12,19 +12,19 @@ import javax.inject.Inject;
 @NotNullByDefault
 public class BriarDataFetcherFactory {
 
-	private final MessagingManager messagingManager;
+	private final ClientHelper clientHelper;
 	@DatabaseExecutor
 	private final Executor dbExecutor;
 
 	@Inject
-	public BriarDataFetcherFactory(MessagingManager messagingManager,
+	public BriarDataFetcherFactory(ClientHelper clientHelper,
 			@DatabaseExecutor Executor dbExecutor) {
-		this.messagingManager = messagingManager;
+		this.clientHelper = clientHelper;
 		this.dbExecutor = dbExecutor;
 	}
 
 	BriarDataFetcher createBriarDataFetcher(AttachmentItem model) {
-		return new BriarDataFetcher(messagingManager, dbExecutor, model);
+		return new BriarDataFetcher(clientHelper, dbExecutor, model);
 	}
 
 }

briar-core/src/main/java/org/briarproject/briar/avatar/AvatarManagerImpl.java

@@ -33,9 +33,8 @@ import org.briarproject.briar.api.avatar.event.AvatarUpdatedEvent;
 import org.briarproject.briar.api.media.Attachment;
 import org.briarproject.briar.api.media.AttachmentHeader;
 import org.briarproject.briar.api.media.FileTooBigException;
-import org.briarproject.briar.api.media.InvalidAttachmentException;
+import org.briarproject.briar.media.AttachmentReader;
 
-import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -254,19 +253,7 @@ class AvatarManagerImpl implements AvatarManager, OpenDatabaseHook, ContactHook,
 
 	@Override
 	public Attachment getAvatar(AttachmentHeader h) throws DbException {
-		MessageId m = h.getMessageId();
-		byte[] body = clientHelper.getMessage(m).getBody();
-		try {
-			BdfDictionary meta = clientHelper.getMessageMetadataAsDictionary(m);
-			String contentType = meta.getString(MSG_KEY_CONTENT_TYPE);
-			if (!contentType.equals(h.getContentType()))
-				throw new InvalidAttachmentException();
-			int offset = meta.getLong(MSG_KEY_DESCRIPTOR_LENGTH).intValue();
-			return new Attachment(h, new ByteArrayInputStream(body, offset,
-					body.length - offset));
-		} catch (FormatException e) {
-			throw new DbException(e);
-		}
+		return AttachmentReader.getAttachment(clientHelper, h);
 	}
 
 	@Nullable

briar-core/src/main/java/org/briarproject/briar/media/AttachmentReader.java

@@ -0,0 +1,44 @@
+package org.briarproject.briar.media;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.client.ClientHelper;
+import org.briarproject.bramble.api.data.BdfDictionary;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.briar.api.media.Attachment;
+import org.briarproject.briar.api.media.AttachmentHeader;
+import org.briarproject.briar.api.media.InvalidAttachmentException;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+
+import static org.briarproject.briar.media.MediaConstants.MSG_KEY_CONTENT_TYPE;
+import static org.briarproject.briar.media.MediaConstants.MSG_KEY_DESCRIPTOR_LENGTH;
+
+public class AttachmentReader {
+
+	public static Attachment getAttachment(ClientHelper clientHelper,
+			AttachmentHeader h) throws DbException {
+		// TODO: Support large messages
+		MessageId m = h.getMessageId();
+		byte[] body = clientHelper.getMessage(m).getBody();
+		try {
+			BdfDictionary meta = clientHelper.getMessageMetadataAsDictionary(m);
+			String contentType = meta.getString(MSG_KEY_CONTENT_TYPE);
+			if (!contentType.equals(h.getContentType()))
+				throw new InvalidAttachmentException();
+			int offset;
+			try {
+				offset = meta.getLong(MSG_KEY_DESCRIPTOR_LENGTH).intValue();
+			} catch (FormatException e) {
+				throw new InvalidAttachmentException();
+			}
+			InputStream stream = new ByteArrayInputStream(body, offset,
+					body.length - offset);
+			return new Attachment(h, stream);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+}

briar-core/src/main/java/org/briarproject/briar/messaging/MessagingManagerImpl.java

@@ -35,14 +35,13 @@ import org.briarproject.briar.api.conversation.DeletionResult;
 import org.briarproject.briar.api.media.Attachment;
 import org.briarproject.briar.api.media.AttachmentHeader;
 import org.briarproject.briar.api.media.FileTooBigException;
-import org.briarproject.briar.api.media.InvalidAttachmentException;
 import org.briarproject.briar.api.messaging.MessagingManager;
 import org.briarproject.briar.api.messaging.PrivateMessage;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.messaging.event.AttachmentReceivedEvent;
 import org.briarproject.briar.api.messaging.event.PrivateMessageReceivedEvent;
+import org.briarproject.briar.media.AttachmentReader;
 
-import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -402,23 +401,7 @@ class MessagingManagerImpl implements MessagingManager, IncomingMessageHook,
 
 	@Override
 	public Attachment getAttachment(AttachmentHeader h) throws DbException {
-		// TODO: Support large messages
-		MessageId m = h.getMessageId();
-		byte[] body = clientHelper.getMessage(m).getBody();
-		try {
-			BdfDictionary meta = clientHelper.getMessageMetadataAsDictionary(m);
-			Long messageType = meta.getOptionalLong(MSG_KEY_MSG_TYPE);
-			if (messageType == null || messageType != ATTACHMENT)
-				throw new InvalidAttachmentException();
-			String contentType = meta.getString(MSG_KEY_CONTENT_TYPE);
-			if (!contentType.equals(h.getContentType()))
-				throw new InvalidAttachmentException();
-			int offset = meta.getLong(MSG_KEY_DESCRIPTOR_LENGTH).intValue();
-			return new Attachment(h, new ByteArrayInputStream(body, offset,
-					body.length - offset));
-		} catch (FormatException e) {
-			throw new DbException(e);
-		}
+		return AttachmentReader.getAttachment(clientHelper, h);
 	}
 
 	@Override