From f915eb4d3676a0a981213fd3d9b9b13a7154b757 Mon Sep 17 00:00:00 2001
From: akwizgran <michael@briarproject.org>
Date: Thu, 6 Dec 2018 16:06:50 +0000
Subject: [PATCH] Add BlockSink interface, using temporary message ID.

---
 .../bramble/api/io/BlockSink.java             | 27 +++++++++++++++++++
 .../bramble/api/io/HashingId.java             | 27 +++++++++++++++++++
 .../bramble/api/sync/SyncConstants.java       |  5 ++++
 3 files changed, 59 insertions(+)
 create mode 100644 bramble-api/src/main/java/org/briarproject/bramble/api/io/BlockSink.java
 create mode 100644 bramble-api/src/main/java/org/briarproject/bramble/api/io/HashingId.java

diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/io/BlockSink.java b/bramble-api/src/main/java/org/briarproject/bramble/api/io/BlockSink.java
new file mode 100644
index 000000000..388311ec9
--- /dev/null
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/io/BlockSink.java
@@ -0,0 +1,27 @@
+package org.briarproject.bramble.api.io;
+
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.tree.TreeHash;
+
+import java.util.List;
+
+public interface BlockSink {
+
+	/**
+	 * Stores a block of the message with the given temporary ID.
+	 */
+	void putBlock(HashingId h, int blockNumber, byte[] data) throws DbException;
+
+	/**
+	 * Sets the hash tree path of a previously stored block.
+	 */
+	void setPath(HashingId h, int blockNumber, List<TreeHash> path)
+			throws DbException;
+
+	/**
+	 * Sets the permanent ID of the message with the given temporary ID. The
+	 * temporary ID is no longer valid once this method has been called.
+	 */
+	void setMessageId(HashingId h, MessageId m) throws DbException;
+}
diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/io/HashingId.java b/bramble-api/src/main/java/org/briarproject/bramble/api/io/HashingId.java
new file mode 100644
index 000000000..d5ca66dbe
--- /dev/null
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/io/HashingId.java
@@ -0,0 +1,27 @@
+package org.briarproject.bramble.api.io;
+
+import org.briarproject.bramble.api.UniqueId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.Message;
+import org.briarproject.bramble.api.sync.MessageId;
+
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * Type-safe wrapper for a byte array that uniquely identifies a
+ * {@link Message} while it's being hashed and the {@link MessageId} is not
+ * yet known.
+ */
+@ThreadSafe
+@NotNullByDefault
+public class HashingId extends UniqueId {
+
+	public HashingId(byte[] id) {
+		super(id);
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		return o instanceof HashingId && super.equals(o);
+	}
+}
diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/sync/SyncConstants.java b/bramble-api/src/main/java/org/briarproject/bramble/api/sync/SyncConstants.java
index a6e3474f3..4a4200872 100644
--- a/bramble-api/src/main/java/org/briarproject/bramble/api/sync/SyncConstants.java
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/sync/SyncConstants.java
@@ -35,4 +35,9 @@ public interface SyncConstants {
 	 * The maximum number of message IDs in an ack, offer or request record.
 	 */
 	int MAX_MESSAGE_IDS = MAX_RECORD_PAYLOAD_BYTES / UniqueId.LENGTH;
+
+	/**
+	 * The maximum length of a message block in bytes.
+	 */
+	int MAX_BLOCK_LENGTH = 32 * 2014; // 32 KiB
 }