_ 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 javax.annotation.Nullable;
   8
   9
  10 /**
  11  * `BackgroundProcessor` takes care of tasks that (1) need to happen periodically to keep
  12  * Rust-Lightning running properly, and (2) either can or should be run in the background. Its
  13  * responsibilities are:
  14  * Processing [`Event`]s with a user-provided [`EventHandler`].
  15  * Monitoring whether the [`ChannelManager`] needs to be re-persisted to disk, and if so,
  16  * writing it to disk/backups by invoking the callback given to it at startup.
  17  * [`ChannelManager`] persistence should be done in the background.
  18  * Calling [`ChannelManager::timer_tick_occurred`] and [`PeerManager::timer_tick_occurred`]
  19  * at the appropriate intervals.
  20  *
  21  * It will also call [`PeerManager::process_events`] periodically though this shouldn't be relied
  22  * upon as doing so may result in high latency.
  23  *
  24  * # Note
  25  *
  26  * If [`ChannelManager`] persistence fails and the persisted manager becomes out-of-date, then
  27  * there is a risk of channels force-closing on startup when the manager realizes it's outdated.
  28  * However, as long as [`ChannelMonitor`] backups are sound, no funds besides those used for
  29  * unilateral chain closure fees are at risk.
  30  *
  31  * [`ChannelMonitor`]: lightning::chain::channelmonitor::ChannelMonitor
  32  * [`Event`]: lightning::util::events::Event
  33  * BackgroundProcessor will immediately stop on drop. It should be stored until shutdown.
  34  */
  35 @SuppressWarnings("unchecked") // We correctly assign various generic arrays
  36 public class BackgroundProcessor extends CommonBase {
  37         BackgroundProcessor(Object _dummy, long ptr) { super(ptr); }
  38         @Override @SuppressWarnings("deprecation")
  39         protected void finalize() throws Throwable {
  40                 super.finalize();
  41                 if (ptr != 0) { bindings.BackgroundProcessor_free(ptr); }
  42         }
  43
  44         /**
  45          * Start a background thread that takes care of responsibilities enumerated in the [top-level
  46          * documentation].
  47          *
  48          * The thread runs indefinitely unless the object is dropped, [`stop`] is called, or
  49          * `persist_manager` returns an error. In case of an error, the error is retrieved by calling
  50          * either [`join`] or [`stop`].
  51          *
  52          * # Data Persistence
  53          *
  54          * `persist_manager` is responsible for writing out the [`ChannelManager`] to disk, and/or
  55          * uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
  56          * [`ChannelManager`]. See [`FilesystemPersister::persist_manager`] for Rust-Lightning's
  57          * provided implementation.
  58          *
  59          * Typically, users should either implement [`ChannelManagerPersister`] to never return an
  60          * error or call [`join`] and handle any error that may arise. For the latter case,
  61          * `BackgroundProcessor` must be restarted by calling `start` again after handling the error.
  62          *
  63          * # Event Handling
  64          *
  65          * `event_handler` is responsible for handling events that users should be notified of (e.g.,
  66          * payment failed). [`BackgroundProcessor`] may decorate the given [`EventHandler`] with common
  67          * functionality implemented by other handlers.
  68          * [`NetGraphMsgHandler`] if given will update the [`NetworkGraph`] based on payment failures.
  69          *
  70          * [top-level documentation]: Self
  71          * [`join`]: Self::join
  72          * [`stop`]: Self::stop
  73          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  74          * [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
  75          * [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
  76          * [`NetworkGraph`]: lightning::routing::network_graph::NetworkGraph
  77          *
  78          * Note that net_graph_msg_handler (or a relevant inner pointer) may be NULL or all-0s to represent None
  79          */
  80         public static BackgroundProcessor start(ChannelManagerPersister persister, EventHandler event_handler, ChainMonitor chain_monitor, ChannelManager channel_manager, @Nullable NetGraphMsgHandler net_graph_msg_handler, PeerManager peer_manager, Logger logger) {
  81                 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);
  82                 if (ret >= 0 && ret <= 4096) { return null; }
  83                 BackgroundProcessor ret_hu_conv = null; if (ret < 0 || ret > 4096) { ret_hu_conv = new BackgroundProcessor(null, ret); }
  84                 ret_hu_conv.ptrs_to.add(ret_hu_conv);
  85                 ret_hu_conv.ptrs_to.add(persister);
  86                 ret_hu_conv.ptrs_to.add(event_handler);
  87                 ret_hu_conv.ptrs_to.add(chain_monitor);
  88                 ret_hu_conv.ptrs_to.add(channel_manager);
  89                 ret_hu_conv.ptrs_to.add(net_graph_msg_handler);
  90                 ret_hu_conv.ptrs_to.add(peer_manager);
  91                 ret_hu_conv.ptrs_to.add(logger);
  92                 return ret_hu_conv;
  93         }
  94
  95         /**
  96          * Join `BackgroundProcessor`'s thread, returning any error that occurred while persisting
  97          * [`ChannelManager`].
  98          *
  99          * # Panics
 100          *
 101          * This function panics if the background thread has panicked such as while persisting or
 102          * handling events.
 103          *
 104          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 105          */
 106         public Result_NoneErrorZ join() {
 107                 long ret = bindings.BackgroundProcessor_join(this.ptr);
 108                 if (ret >= 0 && ret <= 4096) { return null; }
 109                 Result_NoneErrorZ ret_hu_conv = Result_NoneErrorZ.constr_from_ptr(ret);
 110                 this.ptrs_to.add(this);
 111                 // Due to rust's strict-ownership memory model, in some cases we need to "move"
 112                 // an object to pass exclusive ownership to the function being called.
 113                 // In most cases, we avoid this being visible in GC'd languages by cloning the object
 114                 // at the FFI layer, creating a new object which Rust can claim ownership of
 115                 // However, in some cases (eg here), there is no way to clone an object, and thus
 116                 // we actually have to pass full ownership to Rust.
 117                 // Thus, after this call, this is reset to null and is now a dummy object.
 118                 this.ptr = 0;
 119                 return ret_hu_conv;
 120         }
 121
 122         /**
 123          * Stop `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 124          * [`ChannelManager`].
 125          *
 126          * # Panics
 127          *
 128          * This function panics if the background thread has panicked such as while persisting or
 129          * handling events.
 130          *
 131          * [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 132          */
 133         public Result_NoneErrorZ stop() {
 134                 long ret = bindings.BackgroundProcessor_stop(this.ptr);
 135                 if (ret >= 0 && ret <= 4096) { return null; }
 136                 Result_NoneErrorZ ret_hu_conv = Result_NoneErrorZ.constr_from_ptr(ret);
 137                 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 }