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crate::ix!();
pub trait FindNextBlocksToDownload {
fn find_next_blocks_to_download(self: Arc<Self>,
nodeid: NodeId,
count: u32,
blocks: &mut Vec<Option<Arc<BlockIndex>>>,
node_staller: &mut NodeId);
}
impl FindNextBlocksToDownload for PeerManager {
/**
| Update pindexLastCommonBlock and
| add not-in-flight missing successors
| to vBlocks, until it has at most count
| entries.
|
*/
#[EXCLUSIVE_LOCKS_REQUIRED(CS_MAIN)]
fn find_next_blocks_to_download(self: Arc<Self>,
nodeid: NodeId,
count: u32,
blocks: &mut Vec<Option<Arc<BlockIndex>>>,
node_staller: &mut NodeId) {
if count == 0 {
return;
}
blocks.reserve(blocks.len() + usize::try_from(count).unwrap());
let state: Amo<NodeState> = create_state(nodeid);
assert!(state.is_some());
// Make sure pindexBestKnownBlock is up to
// date, we'll need it.
self.clone().process_block_availability(nodeid);
let best_known_block = &state.get().pindex_best_known_block;
let active_n_chain_work = {
self.chainman.get()
.active_chain()
.tip()
.as_ref()
.unwrap()
.n_chain_work
.clone()
};
if best_known_block.is_none()
|| best_known_block.as_ref().unwrap().n_chain_work < active_n_chain_work
|| best_known_block.as_ref().unwrap().n_chain_work < *N_MINIMUM_CHAIN_WORK
{
// This peer has nothing interesting.
return;
}
if state.get().pindex_last_common_block.is_none() {
let chainman = self.chainman.get();
let active_chain = chainman.active_chain();
let active_chain_height
= active_chain.height().unwrap();
let best_known_block_height
= state.get().pindex_best_known_block.as_ref().unwrap().n_height;
let common_height = min(
best_known_block_height,
active_chain_height.try_into().unwrap()
);
// Bootstrap quickly by guessing
// a parent of our best tip is the
// forking point.
//
// Guessing wrong in either direction
// is not a problem.
state.get_mut().pindex_last_common_block
= active_chain[common_height].clone();
}
// If the peer reorganized, our previous
// pindexLastCommonBlock may not be an
// ancestor of its current tip anymore. Go
// back enough to fix that.
state.get_mut().pindex_last_common_block
= last_common_ancestor(
state.get().pindex_last_common_block.clone(),
state.get().pindex_best_known_block.clone()
);
if state.get().pindex_last_common_block.as_ref().unwrap()
== state.get().pindex_best_known_block.as_ref().unwrap() {
return;
}
let consensus_params: Arc<ChainConsensusParams> = self.chainparams.get_consensus();
let mut to_fetch: Vec<Option<Arc<BlockIndex>>> = vec![];
let mut pindex_walk: Option<Arc<BlockIndex>> = state.get().pindex_last_common_block.clone();
let last_common_block_height =
state.get()
.pindex_last_common_block
.as_ref()
.unwrap()
.n_height;
// Never fetch further than the best block
// we know the peer has, or more than
// BLOCK_DOWNLOAD_WINDOW + 1 beyond the
// last linked block we have in common
// with this peer. The +1 is so we can
// detect stalling, namely if we would be
// able to download that next block if the
// window were 1 larger.
let n_window_end: i32 =
last_common_block_height
+ i32::try_from(BLOCK_DOWNLOAD_WINDOW).unwrap();
let n_max_height: i32 = min(
state.get()
.pindex_best_known_block
.as_ref()
.unwrap()
.n_height,
n_window_end + 1
);
let mut waitingfor: NodeId = -1;
while pindex_walk
.as_ref()
.unwrap()
.n_height < n_max_height
{
// Read up to 128 (or more, if more
// blocks than that are needed)
// successors of pindexWalk (towards
// pindexBestKnownBlock) into
// vToFetch. We fetch 128, because
// CBlockIndex::GetAncestor may be as
// expensive as iterating over ~100
// CBlockIndex* entries anyway.
let n_to_fetch: i32 = min(
n_max_height
- pindex_walk
.as_ref()
.unwrap()
.n_height,
max(
(count - u32::try_from(blocks.len()).unwrap()).try_into().unwrap(),
128
)
);
to_fetch.resize(
n_to_fetch.try_into().unwrap(),
None
);
pindex_walk = state
.get()
.pindex_best_known_block
.as_ref()
.unwrap()
.clone()
.get_ancestor(pindex_walk.as_ref().unwrap().n_height + n_to_fetch);
to_fetch[usize::try_from(n_to_fetch - 1).unwrap()] = pindex_walk.clone();
for i in ((0 + 1)..=n_to_fetch - 1).rev() {
to_fetch[usize::try_from(i - 1).unwrap()]
= to_fetch[usize::try_from(i).unwrap()].as_ref().unwrap().pprev.clone();
}
// Iterate over those blocks in
// vToFetch (in forward direction),
// adding the ones that are not yet
// downloaded and not in flight to
// vBlocks. In the meantime, update
// pindexLastCommonBlock as long as
// all ancestors are already
// downloaded, or if it's already part
// of our chain (and therefore don't
// need it even if pruned).
for pindex in to_fetch.iter() {
if !pindex.as_ref().unwrap().is_valid(Some(BlockStatus::BLOCK_VALID_TREE)) {
// We consider the chain that
// this peer is on invalid.
return;
}
if !create_state(nodeid).get().have_witness.load(atomic::Ordering::Relaxed)
&& deployment_active_at_with_buried_deployment(
pindex.clone().unwrap(),
&consensus_params,
ConsensusBuriedDeployment::DEPLOYMENT_SEGWIT
)
{
// We wouldn't download this
// block or its descendants
// from this peer.
return;
}
if (pindex.as_ref().unwrap().n_status & BlockStatus::BLOCK_HAVE_DATA.bits()) != 0
|| self.chainman.get().active_chain().contains(pindex.clone())
{
if pindex.as_ref().unwrap().have_txs_downloaded() {
state.get_mut().pindex_last_common_block = pindex.clone();
}
} else {
if !self.inner.lock().is_block_requested(
&pindex.as_ref().unwrap().get_block_hash()
) {
// The block is not
// already downloaded, and
// not yet in flight.
if pindex.as_ref().unwrap().n_height > n_window_end {
// We reached the end of the window.
if blocks.len() == 0 && waitingfor != nodeid {
// We aren't able
// to fetch
// anything, but
// we would be if
// the download
// window was one
// larger.
*node_staller = waitingfor;
}
return;
}
blocks.push(pindex.clone());
if blocks.len() == count.try_into().unwrap() {
return;
}
} else {
if waitingfor == -1 {
let idx: u256 = pindex
.as_ref().unwrap()
.get_block_hash();
let inner = self.inner.lock();
let mbif = inner.map_blocks_in_flight.lock();
// This is the first
// already-in-flight
// block.
waitingfor = mbif[&idx].0;
}
}
}
}
}
}
}