_ 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`] and [`PeerManager::timer_tick_occurred`]
  20  * at the appropriate intervals.
  21  * Calling [`NetworkGraph::remove_stale_channels`] (if a [`NetGraphMsgHandler`] is provided to
  22  * [`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  29  * If [`ChannelManager`] persistence fails and the persisted manager becomes out-of-date, then
  30  * there is a risk of channels force-closing on startup when the manager realizes it's outdated.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  * [`ChannelMonitor`]: lightning::chain::channelmonitor::ChannelMonitor
  35  * [`Event`]: lightning::util::events::Event
  36  * BackgroundProcessor will immediately stop on drop. It should be stored until shutdown.
  37  */
  38 @SuppressWarnings("unchecked") // We correctly assign various generic arrays
  39 public class BackgroundProcessor extends CommonBase {
  40         BackgroundProcessor(Object _dummy, long ptr) { super(ptr); }
  41         @Override @SuppressWarnings("deprecation")
  42         protected void finalize() throws Throwable {
  43                 super.finalize();
  44                 if (ptr != 0) { bindings.BackgroundProcessor_free(ptr); }
  45         }
  46
  47         /**
  48          * Start a background thread that takes care of responsibilities enumerated in the [top-level
  49          * documentation].
  50          *
  51          * The thread runs indefinitely unless the object is dropped, [`stop`] is called, or
  52          * [`Persister::persist_manager`] returns an error. In case of an error, the error is retrieved by calling
  53          * either [`join`] or [`stop`].
  54          *
  55          * # Data Persistence
  56          *
  57          * [`Persister::persist_manager`] is responsible for writing out the [`ChannelManager`] to disk, and/or
  58          * uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
  59          * [`ChannelManager`]. See [`FilesystemPersister::persist_manager`] for Rust-Lightning's
  60          * provided implementation.
  61          *
  62          * [`Persister::persist_graph`] is responsible for writing out the [`NetworkGraph`] to disk. See
  63          * [`NetworkGraph::write`] for writing out a [`NetworkGraph`]. See [`FilesystemPersister::persist_network_graph`]
  64          * for Rust-Lightning's provided implementation.
  65          *
  66          * Typically, users should either implement [`Persister::persist_manager`] to never return an
  67          * error or call [`join`] and handle any error that may arise. For the latter case,
  68          * `BackgroundProcessor` must be restarted by calling `start` again after handling the error.
  69          *
  70          * # Event Handling
  71          *
  72          * `event_handler` is responsible for handling events that users should be notified of (e.g.,
  73          * payment failed). [`BackgroundProcessor`] may decorate the given [`EventHandler`] with common
  74          * functionality implemented by other handlers.
  75          * [`NetGraphMsgHandler`] if given will update the [`NetworkGraph`] based on payment failures.
  76          *
  77          * [top-level documentation]: BackgroundProcessor
  78          * [`join`]: Self::join
  79          * [`stop`]: Self::stop
  80          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  81          * [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
  82          * [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
  83          * [`FilesystemPersister::persist_network_graph`]: lightning_persister::FilesystemPersister::persist_network_graph
  84          * [`NetworkGraph`]: lightning::routing::network_graph::NetworkGraph
  85          * [`NetworkGraph::write`]: lightning::routing::network_graph::NetworkGraph#impl-Writeable
  86          *
  87          * Note that net_graph_msg_handler (or a relevant inner pointer) may be NULL or all-0s to represent None
  88          */
  89         public static BackgroundProcessor start(Persister persister, EventHandler event_handler, ChainMonitor chain_monitor, ChannelManager channel_manager, @Nullable NetGraphMsgHandler net_graph_msg_handler, PeerManager peer_manager, Logger logger) {
  90                 long ret = bindings.BackgroundProcessor_start(persister == null ? 0 : persister.ptr, event_handler == null ? 0 : event_handler.ptr, chain_monitor == null ? 0 : chain_monitor.ptr & ~1, channel_manager == null ? 0 : channel_manager.ptr & ~1, net_graph_msg_handler == null ? 0 : net_graph_msg_handler.ptr & ~1, peer_manager == null ? 0 : peer_manager.ptr & ~1, logger == null ? 0 : logger.ptr);
  91                 Reference.reachabilityFence(persister);
  92                 Reference.reachabilityFence(event_handler);
  93                 Reference.reachabilityFence(chain_monitor);
  94                 Reference.reachabilityFence(channel_manager);
  95                 Reference.reachabilityFence(net_graph_msg_handler);
  96                 Reference.reachabilityFence(peer_manager);
  97                 Reference.reachabilityFence(logger);
  98                 if (ret >= 0 && ret <= 4096) { return null; }
  99                 BackgroundProcessor ret_hu_conv = null; if (ret < 0 || ret > 4096) { ret_hu_conv = new BackgroundProcessor(null, ret); }
 100                 ret_hu_conv.ptrs_to.add(ret_hu_conv);
 101                 ret_hu_conv.ptrs_to.add(persister);
 102                 ret_hu_conv.ptrs_to.add(event_handler);
 103                 ret_hu_conv.ptrs_to.add(chain_monitor);
 104                 ret_hu_conv.ptrs_to.add(channel_manager);
 105                 ret_hu_conv.ptrs_to.add(net_graph_msg_handler);
 106                 ret_hu_conv.ptrs_to.add(peer_manager);
 107                 ret_hu_conv.ptrs_to.add(logger);
 108                 return ret_hu_conv;
 109         }
 110
 111         /**
 112          * Join `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 113          * [`ChannelManager`].
 114          *
 115          * # Panics
 116          *
 117          * This function panics if the background thread has panicked such as while persisting or
 118          * handling events.
 119          *
 120          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 121          */
 122         public Result_NoneErrorZ join() {
 123                 long ret = bindings.BackgroundProcessor_join(this.ptr);
 124                 Reference.reachabilityFence(this);
 125                 if (ret >= 0 && ret <= 4096) { return null; }
 126                 Result_NoneErrorZ ret_hu_conv = Result_NoneErrorZ.constr_from_ptr(ret);
 127                 this.ptrs_to.add(this);
 128                 // Due to rust's strict-ownership memory model, in some cases we need to "move"
 129                 // an object to pass exclusive ownership to the function being called.
 130                 // In most cases, we avoid this being visible in GC'd languages by cloning the object
 131                 // at the FFI layer, creating a new object which Rust can claim ownership of
 132                 // However, in some cases (eg here), there is no way to clone an object, and thus
 133                 // we actually have to pass full ownership to Rust.
 134                 // Thus, after this call, this is reset to null and is now a dummy object.
 135                 this.ptr = 0;;
 136                 return ret_hu_conv;
 137         }
 138
 139         /**
 140          * Stop `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 141          * [`ChannelManager`].
 142          *
 143          * # Panics
 144          *
 145          * This function panics if the background thread has panicked such as while persisting or
 146          * handling events.
 147          *
 148          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 149          */
 150         public Result_NoneErrorZ stop() {
 151                 long ret = bindings.BackgroundProcessor_stop(this.ptr);
 152                 Reference.reachabilityFence(this);
 153                 if (ret >= 0 && ret <= 4096) { return null; }
 154                 Result_NoneErrorZ ret_hu_conv = Result_NoneErrorZ.constr_from_ptr(ret);
 155                 this.ptrs_to.add(this);
 156                 // Due to rust's strict-ownership memory model, in some cases we need to "move"
 157                 // an object to pass exclusive ownership to the function being called.
 158                 // In most cases, we avoid this being visible in GC'd languages by cloning the object
 159                 // at the FFI layer, creating a new object which Rust can claim ownership of
 160                 // However, in some cases (eg here), there is no way to clone an object, and thus
 161                 // we actually have to pass full ownership to Rust.
 162                 // Thus, after this call, this is reset to null and is now a dummy object.
 163                 this.ptr = 0;;
 164                 return ret_hu_conv;
 165         }
 166
 167 }