chain: extend fn MSRV

src/chain/header_chain.rs

@@ -154,7 +154,7 @@ impl HeaderChain {
  locators
  }
 
- // Extend the current chain, potentially rewriting history
+ // Extend the current chain, potentially rewriting history. Higher order functions should decide what we extend
  pub(crate) fn extend(&mut self, batch: &[Header]) -> Vec<DisconnectedHeader> {
  let mut reorged = Vec::new();
  // We cannot extend from nothing
@@ -180,38 +180,31 @@ impl HeaderChain {
  .expect("cannot extend from empty batch")
  .prev_blockhash
  ));
- while let Some((height, header)) = self.headers.iter_mut().next_back() {
+ // Supporting MSRV of 1.63 requires this round-about way of removing the headers instead of `pop_last`
+ // Find the header that matches the new batch prev block hash, collecting the disconnected headers
+ for (height, header) in self.headers.iter().rev() {
  if header.block_hash().ne(&batch
  .first()
  .expect("cannot extend from empty batch")
  .prev_blockhash)
  {
- reorged.push(DisconnectedHeader::new(*height, *header));
+ reorged.push(DisconnectedHeader::new(*height, header.block_hash()));
  } else {
- let anchor_height = self.height();
- for (index, header) in batch.iter().enumerate() {
- self.headers
- .insert(anchor_height + 1 + index as u32, *header);
- }
+ break;
  }
  }
- // // Remove items from the top of the chain until they link.
- // while self.tip().ne(&batch
- // .first()
- // .expect("cannot extend from empty batch")
- // .prev_blockhash)
- // {
- // if let Some((height, header)) = self.headers.pop_last() {
- // reorged.push(DisconnectedHeader::new(height, header));
- // }
- // }
- // let current_anchor = self.height();
- // for (index, header) in batch.iter().enumerate() {
- // self.headers
- // .insert(current_anchor + 1 + index as u32, *header);
- // }
+ // Actually remove anything that should no longer be connected
+ for removal in reorged.iter() {
+ self.remove(&removal.height);
+ }
+ // Add back the new headers, starting at the proper link
+ let current_anchor = self.height();
+ for (index, header) in batch.iter().enumerate() {
+ self.headers
+ .insert(current_anchor + 1 + index as u32, *header);
+ }
  }
- reorged.iter().rev().copied().collect()
+ reorged
  }
 
  fn remove(&mut self, height: &u32) {

src/lib.rs

@@ -45,11 +45,11 @@ pub struct DisconnectedHeader {
  /// The height where this header used to be in the chain.
  pub height: u32,
  /// The reorganized header.
- pub header: Header,
+ pub header: BlockHash,
 }
 
 impl DisconnectedHeader {
- pub(crate) fn new(height: u32, header: Header) -> Self {
+ pub(crate) fn new(height: u32, header: BlockHash) -> Self {
  Self { height, header }
  }
 }