From 210577482a786c19f522f1fa99a928892c29fa0a Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Fri, 5 Mar 2021 14:31:17 -0500
Subject: [PATCH] Add deserialization/init helper class that overtorment asked
 for

---
 .../batteries/ChannelManagerConstructor.java  | 87 +++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 src/main/java/org/ldk/batteries/ChannelManagerConstructor.java

diff --git a/src/main/java/org/ldk/batteries/ChannelManagerConstructor.java b/src/main/java/org/ldk/batteries/ChannelManagerConstructor.java
new file mode 100644
index 00000000..2a23d718
--- /dev/null
+++ b/src/main/java/org/ldk/batteries/ChannelManagerConstructor.java
@@ -0,0 +1,87 @@
+package org.ldk.batteries;
+
+import org.ldk.enums.LDKNetwork;
+import org.ldk.structs.*;
+import org.ldk.util.TwoTuple;
+
+
+/**
+ * A simple utility class which assists in constructing a fresh or deserializing from disk a ChannelManager and one or
+ * more ChannelMonitors.
+ */
+public class ChannelManagerConstructor {
+    /**
+     * An Exception that indicates the serialized data is invalid and has been corrupted on disk. You should attempt to
+     * restore from a backup if there is one which is known to be current. Otherwise, funds may have been lost.
+     */
+    public static class InvalidSerializedDataException extends Exception {}
+
+    /**
+     * The ChannelManager either deserialized or newly-constructed.
+     */
+    public final ChannelManager channel_manager;
+    /**
+     * The latest block has the channel manager saw. If this is non-null it is a 32-byte block hash.
+     * You should sync the blockchain starting with the block that builds on this block.
+     */
+    public final byte[] channel_manager_latest_block_hash;
+    /**
+     * A list of ChannelMonitors and the last block they each saw. You should sync the blockchain on each individually
+     * starting with the block that builds on the hash given.
+     * After doing so (and syncing the blockchain on the channel manager as well), you should call chain_sync_completed()
+     * and then continue to normal application operation.
+     */
+    public final TwoTuple<ChannelMonitor, byte[]>[] channel_monitors;
+
+    private final Watch chain_watch;
+
+    /**
+     * Deserializes a channel manager and a set of channel monitors from the given serialized copies and interface implementations
+     */
+    public ChannelManagerConstructor(byte[] channel_manager_serialized, byte[][] channel_monitors_serialized,
+                                     KeysInterface keys_interface, FeeEstimator fee_estimator, Watch chain_watch,
+                                     BroadcasterInterface tx_broadcaster, Logger logger) throws InvalidSerializedDataException {
+        final ChannelMonitor[] monitors = new ChannelMonitor[channel_monitors_serialized.length];
+        this.channel_monitors = new TwoTuple[monitors.length];
+        for (int i = 0; i < monitors.length; i++) {
+            Result_C2Tuple_BlockHashChannelMonitorZDecodeErrorZ res = UtilMethods.constructor_BlockHashChannelMonitorZ_read(channel_monitors_serialized[i], keys_interface);
+            if (res instanceof Result_C2Tuple_BlockHashChannelMonitorZDecodeErrorZ.Result_C2Tuple_BlockHashChannelMonitorZDecodeErrorZ_Err) {
+                throw new InvalidSerializedDataException();
+            }
+            monitors[i] = ((Result_C2Tuple_BlockHashChannelMonitorZDecodeErrorZ.Result_C2Tuple_BlockHashChannelMonitorZDecodeErrorZ_OK) res).res.b;
+            this.channel_monitors[i] = new TwoTuple<>(monitors[i], ((Result_C2Tuple_BlockHashChannelMonitorZDecodeErrorZ.Result_C2Tuple_BlockHashChannelMonitorZDecodeErrorZ_OK)res).res.a);
+        }
+        Result_C2Tuple_BlockHashChannelManagerZDecodeErrorZ res =
+                UtilMethods.constructor_BlockHashChannelManagerZ_read(channel_manager_serialized, keys_interface, fee_estimator, chain_watch, tx_broadcaster,
+                        logger, UserConfig.constructor_default(), monitors);
+        if (res instanceof Result_C2Tuple_BlockHashChannelManagerZDecodeErrorZ.Result_C2Tuple_BlockHashChannelManagerZDecodeErrorZ_Err) {
+            throw new InvalidSerializedDataException();
+        }
+        this.channel_manager = ((Result_C2Tuple_BlockHashChannelManagerZDecodeErrorZ.Result_C2Tuple_BlockHashChannelManagerZDecodeErrorZ_OK)res).res.b;
+        this.channel_manager_latest_block_hash = ((Result_C2Tuple_BlockHashChannelManagerZDecodeErrorZ.Result_C2Tuple_BlockHashChannelManagerZDecodeErrorZ_OK)res).res.a;
+        this.chain_watch = chain_watch;
+    }
+
+    /**
+     * Constructs a channel manager from the given interface implementations
+     */
+    public ChannelManagerConstructor(LDKNetwork network, UserConfig config, byte[] current_blockchain_tip_hash, int current_blockchain_tip_height,
+                                     KeysInterface keys_interface, FeeEstimator fee_estimator, Watch chain_watch,
+                                     BroadcasterInterface tx_broadcaster, Logger logger) throws InvalidSerializedDataException {
+        channel_monitors = new TwoTuple[0];
+        channel_manager_latest_block_hash = null;
+        this.chain_watch = chain_watch;
+        // Note that current_blockchain_tip_hash will be required in a future version but is currently unused.
+        channel_manager = ChannelManager.constructor_new(network, fee_estimator, chain_watch, tx_broadcaster, logger, keys_interface, config, current_blockchain_tip_height);
+    }
+
+    /**
+     * Utility which adds all of the deserialized ChannelMonitors to the chain watch so that further updates from the
+     * ChannelManager are processed as normal.
+     */
+    public void chain_sync_completed() {
+        for (TwoTuple<ChannelMonitor, byte[]> monitor: channel_monitors) {
+            this.chain_watch.watch_channel(monitor.a.get_funding_txo().a, monitor.a);
+        }
+    }
+}
-- 
2.39.5