feat: marf squash engine

changelog.d/marf-squash-engine.added

@@ -0,0 +1 @@
+Add MARF squash engine (`squash_to_path`) and squash-aware trie lookups for root hashes and block heights

stackslib/src/chainstate/stacks/index/marf.rs

@@ -24,6 +24,9 @@ use rusqlite::{Connection, Transaction};
 use stacks_common::types::chainstate::{TrieHash, TRIEHASH_ENCODED_SIZE};
 use stacks_common::util::hash::Sha512Trunc256Sum;
 
+pub use super::squash::{
+    SquashStats, MARF_SQUASHED_BLOCK_ROOT_HASH_KEY, MARF_SQUASH_HEIGHT_KEY, MARF_SQUASH_ROOT_KEY,
+};
 use super::storage::ReopenedTrieStorageConnection;
 use crate::chainstate::stacks::index::bits::{get_leaf_hash, get_node_hash};
 use crate::chainstate::stacks::index::node::{
@@ -35,7 +38,9 @@ use crate::chainstate::stacks::index::storage::{
     TrieStorageTransaction,
 };
 use crate::chainstate::stacks::index::trie::Trie;
-use crate::chainstate::stacks::index::{Error, MARFValue, MarfTrieId, TrieLeaf, TrieMerkleProof};
+use crate::chainstate::stacks::index::{
+    trie_sql, Error, MARFValue, MarfTrieId, TrieLeaf, TrieMerkleProof,
+};
 use crate::util_lib::db::Error as db_error;
 
 pub const BLOCK_HASH_TO_HEIGHT_MAPPING_KEY: &str = "__MARF_BLOCK_HASH_TO_HEIGHT";
@@ -1341,6 +1346,16 @@ impl<T: MarfTrieId> MARF<T> {
             }
         }
 
+        // In a squashed MARF, OWN_BLOCK_HEIGHT_KEY returns the squash
+        // height H for every block in the squashed range.  Use the
+        // side-table when available.
+        if storage.squash_info().is_some() {
+            if let Some(h) = trie_sql::read_squash_block_height(storage.sqlite_conn(), block_hash)?
+            {
+                return Ok(Some(h));
+            }
+        }
+
         let marf_value = if block_hash == current_block_hash {
             MARF::get_by_key(storage, current_block_hash, OWN_BLOCK_HEIGHT_KEY)?
         } else {

stackslib/src/chainstate/stacks/index/mod.rs

@@ -33,6 +33,7 @@ pub mod marf;
 pub mod node;
 pub mod profile;
 pub mod proofs;
+pub mod squash;
 pub mod storage;
 pub mod trie;
 pub mod trie_sql;