create partial chainstates from a full chainstate

crates/floresta-chain/src/pruned_utreexo/chain_state.rs

@@ -7,6 +7,7 @@ use alloc::fmt::format;
 use alloc::string::ToString;
 use alloc::sync::Arc;
 use alloc::vec::Vec;
+use core::cell::UnsafeCell;
 #[cfg(feature = "bitcoinconsensus")]
 use core::ffi::c_uint;
 
@@ -41,6 +42,8 @@ use super::chainstore::KvChainStore;
 use super::consensus::Consensus;
 use super::error::BlockValidationErrors;
 use super::error::BlockchainError;
+use super::partial_chain::PartialChainState;
+use super::partial_chain::PartialChainStateInner;
 use super::BlockchainInterface;
 use super::ChainStore;
 use super::UpdatableChainstate;
@@ -107,6 +110,7 @@ impl<PersistedState: ChainStore> ChainState<PersistedState> {
             _ => {}
         }
     }
+
     /// Just adds headers to the chainstate, without validating them.
     pub fn push_headers(
         &self,
@@ -1033,6 +1037,32 @@ impl<PersistedState: ChainStore> UpdatableChainstate for ChainState<PersistedSta
         let inner = read_lock!(self);
         inner.acc.roots.clone()
     }
+
+    fn get_partial_chain(
+        &self,
+        initial_height: u32,
+        final_height: u32,
+        acc: Stump,
+    ) -> Result<super::partial_chain::PartialChainState, BlockchainError> {
+        let blocks = (initial_height..=final_height)
+            .map(|height| self.get_block_header_by_height(height))
+            .collect();
+
+        let inner = PartialChainStateInner {
+            error: None,
+            blocks,
+            consensus: Consensus {
+                parameters: self.chain_params(),
+            },
+            current_acc: acc,
+            final_height,
+            assume_valid: false,
+            initial_height,
+            current_height: initial_height,
+        };
+
+        Ok(PartialChainState(UnsafeCell::new(inner)))
+    }
 }
 
 impl<T: ChainStore> From<ChainStateBuilder<T>> for ChainState<T> {

crates/floresta-chain/src/pruned_utreexo/error.rs

@@ -38,7 +38,9 @@ pub enum BlockValidationErrors {
     BlockExtendsAnOrphanChain,
     BadBip34,
     InvalidProof,
+    CoinbaseNotMatured,
 }
+
 impl Display for BlockValidationErrors {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match self {
@@ -67,6 +69,9 @@ impl Display for BlockValidationErrors {
             }
             BlockValidationErrors::BadBip34 => write!(f, "BIP34 commitment mismatch"),
             BlockValidationErrors::InvalidProof => write!(f, "Invalid proof"),
+            BlockValidationErrors::CoinbaseNotMatured => {
+                write!(f, "Coinbase not matured yet")
+            }
         }
     }
 }

crates/floresta-chain/src/pruned_utreexo/mod.rs

@@ -20,7 +20,9 @@ use bitcoin::Transaction;
 use bitcoin::TxOut;
 use rustreexo::accumulator::node_hash::NodeHash;
 use rustreexo::accumulator::proof::Proof;
+use rustreexo::accumulator::stump::Stump;
 
+use self::partial_chain::PartialChainState;
 use crate::prelude::*;
 use crate::BestChain;
 use crate::BlockConsumer;
@@ -102,6 +104,23 @@ pub trait UpdatableChainstate {
     fn process_rescan_block(&self, block: &Block) -> Result<(), BlockchainError>;
     /// Returns the root hashes of our utreexo forest
     fn get_root_hashes(&self) -> Vec<NodeHash>;
+    /// Returns a partial chainstate from a range of blocks.
+    ///
+    /// [PartialChainState] is a simplified version of `ChainState` that is used during IBD.
+    /// It doesn't suport reorgs, only hold headers for a subset of blocks and isn't [Sync].
+    /// The idea here is that you take a OS thread or some async task that will drive one
+    /// [PartialChainState] to completion by downloading blocks inside that chainstate's range.
+    /// If all goes right, it'll end without error, and you should mark blocks in this range as
+    /// valid.
+    ///
+    /// Since this chainstate may start from a height with an existing UTXO set, you need to
+    /// provide a [Stump] for that block.
+    fn get_partial_chain(
+        &self,
+        initial_height: u32,
+        final_height: u32,
+        acc: Stump,
+    ) -> Result<PartialChainState, BlockchainError>;
 }
 
 /// [ChainStore] is a trait defining how we interact with our chain database. This definitions