96a9aa6e63474dbd93a2ef969eef5b07c79e6491 feat(chain): refactor `merge_chains` (志宇)
2f22987c9e924800f8682b2dcbdde60fd26b069a chore(chain): fix comment (志宇)
daf588f016ec3118c875db8ed6b55fa03683f0f6 feat(chain): optimize `merge_chains` (志宇)
77d35954c1f3a18f767267e9097f63ca11c709ec feat(chain)!: rm `local_chain::Update` (志宇)
1269b0610efb7bd86d92a909800f9330568c797a test(chain): fix incorrect test case (志宇)
72fe65b65f297ebb7160eee6859c46e29c2d9528 feat(esplora)!: simplify chain update logic (志宇)
eded1a7ea0c6a4b9664826df4f77b714cbad0bcc feat(chain): introduce `CheckPoint::insert` (志宇)
519cd75d23fbb72321b0b189dca12afbfd78c0c7 test(esplora): move esplora tests into src files (志宇)
a6e613e6b978b995abf6c92a16df0300b113aa2c test(esplora): add `test_finalize_chain_update` (志宇)
494d253493f1bc914adba16a28ccf1bc0a0f4ec8 feat(testenv): add `genesis_hash` method (志宇)
886d72e3d541d088320bbdad6804057f32aca684 chore(chain)!: rm `missing_heights` and `missing_heights_from` methods (志宇)
bd62aa0fe199d676710c9909617198d62f4897c0 feat(esplora)!: remove `EsploraExt::update_local_chain` (志宇)
1e997939837e9c1f0c087d6d28ac12e373c8c05f feat(testenv): add `make_checkpoint_tip` (志宇)
Pull request description:
Fixes#1354
### Description
Built on top of both #1369 and #1373, we simplify the `EsploraExt` API by removing the `update_local_chain` method and having `full_scan` and `sync` update the local chain in the same call. The `full_scan` and `sync` methods now takes in an additional input (`local_tip`) which provides us with the view of the `LocalChain` before the update. These methods now return structs `FullScanUpdate` and `SyncUpdate`.
The examples are updated to use this new API. `TxGraph::missing_heights` and `tx_graph::ChangeSet::missing_heights_from` are no longer needed, therefore they are removed.
Additionally, we used this opportunity to simplify the logic which updates `LocalChain`. We got rid of the `local_chain::Update` struct (which contained the update `CheckPoint` tip and a `bool` which signaled whether we want to introduce blocks below point of agreement). It turns out we can use something like `CheckPoint::insert` so the chain source can craft an update based on the old tip. This way, we can make better use of `merge_chains`' optimization that compares the `Arc` pointers of the local and update chain (before we were crafting the update chain NOT based on top of the previous local chain). With this, we no longer need the `Update::introduce_older_block` field since the logic will naturally break when we reach a matching `Arc` pointer.
### Notes to the reviewers
* Obtaining the `LocalChain`'s update now happens within `EsploraExt::full_scan` and `EsploraExt::sync`. Creating the `LocalChain` update is now split into two methods (`fetch_latest_blocks` and `chain_update`) that are called before and after fetching transactions and anchors.
* We need to duplicate code for `bdk_esplora`. One for blocking and one for async.
### Changelog notice
* Changed `EsploraExt` API so that sync only requires one round of fetching data. The `local_chain_update` method is removed and the `local_tip` parameter is added to the `full_scan` and `sync` methods.
* Removed `TxGraph::missing_heights` and `tx_graph::ChangeSet::missing_heights_from` methods.
* Introduced `CheckPoint::insert` which allows convenient checkpoint-insertion. This is intended for use by chain-sources when crafting an update.
* Refactored `merge_chains` to also return the resultant `CheckPoint` tip.
* Optimized the update `LocalChain` logic - use the update `CheckPoint` as the new `CheckPoint` tip when possible.
### Checklists
#### All Submissions:
* [x] I've signed all my commits
* [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
* [x] I ran `cargo fmt` and `cargo clippy` before committing
#### New Features:
* [x] I've added tests for the new feature
* [x] I've added docs for the new feature
ACKs for top commit:
LLFourn:
ACK 96a9aa6e63474dbd93a2ef969eef5b07c79e6491
Tree-SHA512: 3d4f2eab08a1fe94eb578c594126e99679f72e231680b2edd4bfb018ba1d998ca123b07acb2d19c644d5887fc36b8e42badba91cd09853df421ded04de45bf69
8e73998cfa