_ Git - ldk-java/blob - src/main/java/org/ldk/structs/BackgroundProcessor.java

   1 package org.ldk.structs;
   2
   3 import org.ldk.impl.bindings;
   4 import org.ldk.enums.*;
   5 import org.ldk.util.*;
   6 import java.util.Arrays;
   7 import java.lang.ref.Reference;
   8 import javax.annotation.Nullable;
   9
  10
  11 /**
  12  * `BackgroundProcessor` takes care of tasks that (1) need to happen periodically to keep
  13  * Rust-Lightning running properly, and (2) either can or should be run in the background. Its
  14  * responsibilities are:
  15  * Processing [`Event`]s with a user-provided [`EventHandler`].
  16  * Monitoring whether the [`ChannelManager`] needs to be re-persisted to disk, and if so,
  17  * writing it to disk/backups by invoking the callback given to it at startup.
  18  * [`ChannelManager`] persistence should be done in the background.
  19  * Calling [`ChannelManager::timer_tick_occurred`], [`ChainMonitor::rebroadcast_pending_claims`]
  20  * and [`PeerManager::timer_tick_occurred`] at the appropriate intervals.
  21  * Calling [`NetworkGraph::remove_stale_channels_and_tracking`] (if a [`GossipSync`] with a
  22  * [`NetworkGraph`] is provided to [`BackgroundProcessor::start`]).
  23  *
  24  * It will also call [`PeerManager::process_events`] periodically though this shouldn't be relied
  25  * upon as doing so may result in high latency.
  26  *
  27  * # Note
  28  *
  29  * If [`ChannelManager`] persistence fails and the persisted manager becomes out-of-date, then
  30  * there is a risk of channels force-closing on startup when the manager realizes it's outdated.
  31  * However, as long as [`ChannelMonitor`] backups are sound, no funds besides those used for
  32  * unilateral chain closure fees are at risk.
  33  *
  34  * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  35  * [`ChannelManager::timer_tick_occurred`]: lightning::ln::channelmanager::ChannelManager::timer_tick_occurred
  36  * [`ChannelMonitor`]: lightning::chain::channelmonitor::ChannelMonitor
  37  * [`Event`]: lightning::events::Event
  38  * [`PeerManager::timer_tick_occurred`]: lightning::ln::peer_handler::PeerManager::timer_tick_occurred
  39  * [`PeerManager::process_events`]: lightning::ln::peer_handler::PeerManager::process_events
  40  * BackgroundProcessor will immediately stop on drop. It should be stored until shutdown.
  41  */
  42 @SuppressWarnings("unchecked") // We correctly assign various generic arrays
  43 public class BackgroundProcessor extends CommonBase {
  44         BackgroundProcessor(Object _dummy, long ptr) { super(ptr); }
  45         @Override @SuppressWarnings("deprecation")
  46         protected void finalize() throws Throwable {
  47                 super.finalize();
  48                 if (ptr != 0) { bindings.BackgroundProcessor_free(ptr); }
  49         }
  50
  51         /**
  52          * Start a background thread that takes care of responsibilities enumerated in the [top-level
  53          * documentation].
  54          *
  55          * The thread runs indefinitely unless the object is dropped, [`stop`] is called, or
  56          * [`Persister::persist_manager`] returns an error. In case of an error, the error is retrieved by calling
  57          * either [`join`] or [`stop`].
  58          *
  59          * # Data Persistence
  60          *
  61          * [`Persister::persist_manager`] is responsible for writing out the [`ChannelManager`] to disk, and/or
  62          * uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
  63          * [`ChannelManager`]. See the `lightning-persister` crate for LDK's
  64          * provided implementation.
  65          *
  66          * [`Persister::persist_graph`] is responsible for writing out the [`NetworkGraph`] to disk, if
  67          * [`GossipSync`] is supplied. See [`NetworkGraph::write`] for writing out a [`NetworkGraph`].
  68          * See the `lightning-persister` crate for LDK's provided implementation.
  69          *
  70          * Typically, users should either implement [`Persister::persist_manager`] to never return an
  71          * error or call [`join`] and handle any error that may arise. For the latter case,
  72          * `BackgroundProcessor` must be restarted by calling `start` again after handling the error.
  73          *
  74          * # Event Handling
  75          *
  76          * `event_handler` is responsible for handling events that users should be notified of (e.g.,
  77          * payment failed). [`BackgroundProcessor`] may decorate the given [`EventHandler`] with common
  78          * functionality implemented by other handlers.
  79          * [`P2PGossipSync`] if given will update the [`NetworkGraph`] based on payment failures.
  80          *
  81          * # Rapid Gossip Sync
  82          *
  83          * If rapid gossip sync is meant to run at startup, pass [`RapidGossipSync`] via `gossip_sync`
  84          * to indicate that the [`BackgroundProcessor`] should not prune the [`NetworkGraph`] instance
  85          * until the [`RapidGossipSync`] instance completes its first sync.
  86          *
  87          * [top-level documentation]: BackgroundProcessor
  88          * [`join`]: Self::join
  89          * [`stop`]: Self::stop
  90          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  91          * [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
  92          * [`Persister::persist_manager`]: lightning::util::persist::Persister::persist_manager
  93          * [`Persister::persist_graph`]: lightning::util::persist::Persister::persist_graph
  94          * [`NetworkGraph`]: lightning::routing::gossip::NetworkGraph
  95          * [`NetworkGraph::write`]: lightning::routing::gossip::NetworkGraph#impl-Writeable
  96          */
  97         public static BackgroundProcessor start(org.ldk.structs.Persister persister, org.ldk.structs.EventHandler event_handler, org.ldk.structs.ChainMonitor chain_monitor, org.ldk.structs.ChannelManager channel_manager, org.ldk.structs.GossipSync gossip_sync, org.ldk.structs.PeerManager peer_manager, org.ldk.structs.Logger logger, org.ldk.structs.Option_WriteableScoreZ scorer) {
  98                 long ret = bindings.BackgroundProcessor_start(persister.ptr, event_handler.ptr, chain_monitor.ptr, channel_manager.ptr, gossip_sync.ptr, peer_manager.ptr, logger.ptr, scorer.ptr);
  99                 Reference.reachabilityFence(persister);
 100                 Reference.reachabilityFence(event_handler);
 101                 Reference.reachabilityFence(chain_monitor);
 102                 Reference.reachabilityFence(channel_manager);
 103                 Reference.reachabilityFence(gossip_sync);
 104                 Reference.reachabilityFence(peer_manager);
 105                 Reference.reachabilityFence(logger);
 106                 Reference.reachabilityFence(scorer);
 107                 if (ret >= 0 && ret <= 4096) { return null; }
 108                 org.ldk.structs.BackgroundProcessor ret_hu_conv = null; if (ret < 0 || ret > 4096) { ret_hu_conv = new org.ldk.structs.BackgroundProcessor(null, ret); }
 109                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(ret_hu_conv); };
 110                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(persister); };
 111                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(event_handler); };
 112                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(chain_monitor); };
 113                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(channel_manager); };
 114                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(gossip_sync); };
 115                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(peer_manager); };
 116                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(logger); };
 117                 if (ret_hu_conv != null) { ret_hu_conv.ptrs_to.add(scorer); };
 118                 return ret_hu_conv;
 119         }
 120
 121         /**
 122          * Join `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 123          * [`ChannelManager`].
 124          *
 125          * # Panics
 126          *
 127          * This function panics if the background thread has panicked such as while persisting or
 128          * handling events.
 129          *
 130          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 131          */
 132         public Result_NoneIOErrorZ join() {
 133                 long ret = bindings.BackgroundProcessor_join(this.ptr);
 134                 Reference.reachabilityFence(this);
 135                 if (ret >= 0 && ret <= 4096) { return null; }
 136                 Result_NoneIOErrorZ ret_hu_conv = Result_NoneIOErrorZ.constr_from_ptr(ret);
 137                 if (this != null) { this.ptrs_to.add(this); };
 138                 // Due to rust's strict-ownership memory model, in some cases we need to "move"
 139                 // an object to pass exclusive ownership to the function being called.
 140                 // In most cases, we avoid this being visible in GC'd languages by cloning the object
 141                 // at the FFI layer, creating a new object which Rust can claim ownership of
 142                 // However, in some cases (eg here), there is no way to clone an object, and thus
 143                 // we actually have to pass full ownership to Rust.
 144                 // Thus, after this call, this is reset to null and is now a dummy object.
 145                 this.ptr = 0;;
 146                 return ret_hu_conv;
 147         }
 148
 149         /**
 150          * Stop `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 151          * [`ChannelManager`].
 152          *
 153          * # Panics
 154          *
 155          * This function panics if the background thread has panicked such as while persisting or
 156          * handling events.
 157          *
 158          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 159          */
 160         public Result_NoneIOErrorZ stop() {
 161                 long ret = bindings.BackgroundProcessor_stop(this.ptr);
 162                 Reference.reachabilityFence(this);
 163                 if (ret >= 0 && ret <= 4096) { return null; }
 164                 Result_NoneIOErrorZ ret_hu_conv = Result_NoneIOErrorZ.constr_from_ptr(ret);
 165                 if (this != null) { this.ptrs_to.add(this); };
 166                 // Due to rust's strict-ownership memory model, in some cases we need to "move"
 167                 // an object to pass exclusive ownership to the function being called.
 168                 // In most cases, we avoid this being visible in GC'd languages by cloning the object
 169                 // at the FFI layer, creating a new object which Rust can claim ownership of
 170                 // However, in some cases (eg here), there is no way to clone an object, and thus
 171                 // we actually have to pass full ownership to Rust.
 172                 // Thus, after this call, this is reset to null and is now a dummy object.
 173                 this.ptr = 0;;
 174                 return ret_hu_conv;
 175         }
 176
 177 }