Fix unused warning for un-accessed enum variant field in net-tokio
[rust-lightning] / lightning-block-sync / src / poll.rs
index 3ff7606b8d9cfdd8db1f9a936c14d4624c9e8945..dcc19a4969dd3eab863c1216b17d434b93f54849 100644 (file)
@@ -1,10 +1,12 @@
-use crate::{AsyncBlockSourceResult, BlockHeaderData, BlockSource, BlockSourceError, BlockSourceResult};
+//! Adapters that make one or more [`BlockSource`]s simpler to poll for new chain tip transitions.
+
+use crate::{AsyncBlockSourceResult, BlockData, BlockHeaderData, BlockSource, BlockSourceError, BlockSourceResult};
 
-use bitcoin::blockdata::block::Block;
 use bitcoin::hash_types::BlockHash;
 use bitcoin::network::constants::Network;
+use lightning::chain::BestBlock;
 
-use std::ops::DerefMut;
+use std::ops::Deref;
 
 /// The `Poll` trait defines behavior for polling block sources for a chain tip and retrieving
 /// related chain data. It serves as an adapter for `BlockSource`.
@@ -15,20 +17,20 @@ use std::ops::DerefMut;
 /// [`ChainPoller`]: ../struct.ChainPoller.html
 pub trait Poll {
        /// Returns a chain tip in terms of its relationship to the provided chain tip.
-       fn poll_chain_tip<'a>(&'a mut self, best_known_chain_tip: ValidatedBlockHeader) ->
+       fn poll_chain_tip<'a>(&'a self, best_known_chain_tip: ValidatedBlockHeader) ->
                AsyncBlockSourceResult<'a, ChainTip>;
 
        /// Returns the header that preceded the given header in the chain.
-       fn look_up_previous_header<'a>(&'a mut self, header: &'a ValidatedBlockHeader) ->
+       fn look_up_previous_header<'a>(&'a self, header: &'a ValidatedBlockHeader) ->
                AsyncBlockSourceResult<'a, ValidatedBlockHeader>;
 
        /// Returns the block associated with the given header.
-       fn fetch_block<'a>(&'a mut self, header: &'a ValidatedBlockHeader) ->
+       fn fetch_block<'a>(&'a self, header: &'a ValidatedBlockHeader) ->
                AsyncBlockSourceResult<'a, ValidatedBlock>;
 }
 
 /// A chain tip relative to another chain tip in terms of block hash and chainwork.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum ChainTip {
        /// A chain tip with the same hash as another chain's tip.
        Common,
@@ -42,7 +44,9 @@ pub enum ChainTip {
 }
 
 /// The `Validate` trait defines behavior for validating chain data.
-pub(crate) trait Validate {
+///
+/// This trait is sealed and not meant to be implemented outside of this crate.
+pub trait Validate: sealed::Validate {
        /// The validated data wrapper which can be dereferenced to obtain the validated data.
        type T: std::ops::Deref<Target = Self>;
 
@@ -55,12 +59,11 @@ impl Validate for BlockHeaderData {
        type T = ValidatedBlockHeader;
 
        fn validate(self, block_hash: BlockHash) -> BlockSourceResult<Self::T> {
-               self.header
-                       .validate_pow(&self.header.target())
-                       .or_else(|e| Err(BlockSourceError::persistent(e)))?;
+               let pow_valid_block_hash = self.header
+                       .validate_pow(self.header.target())
+                       .map_err(BlockSourceError::persistent)?;
 
-               // TODO: Use the result of validate_pow instead of recomputing the block hash once upstream.
-               if self.header.block_hash() != block_hash {
+               if pow_valid_block_hash != block_hash {
                        return Err(BlockSourceError::persistent("invalid block hash"));
                }
 
@@ -68,25 +71,31 @@ impl Validate for BlockHeaderData {
        }
 }
 
-impl Validate for Block {
+impl Validate for BlockData {
        type T = ValidatedBlock;
 
        fn validate(self, block_hash: BlockHash) -> BlockSourceResult<Self::T> {
-               self.header
-                       .validate_pow(&self.header.target())
-                       .or_else(|e| Err(BlockSourceError::persistent(e)))?;
+               let header = match &self {
+                       BlockData::FullBlock(block) => &block.header,
+                       BlockData::HeaderOnly(header) => header,
+               };
+
+               let pow_valid_block_hash = header
+                       .validate_pow(header.target())
+                       .map_err(BlockSourceError::persistent)?;
 
-               // TODO: Use the result of validate_pow instead of recomputing the block hash once upstream.
-               if self.block_hash() != block_hash {
+               if pow_valid_block_hash != block_hash {
                        return Err(BlockSourceError::persistent("invalid block hash"));
                }
 
-               if !self.check_merkle_root() {
-                       return Err(BlockSourceError::persistent("invalid merkle root"));
-               }
+               if let BlockData::FullBlock(block) = &self {
+                       if !block.check_merkle_root() {
+                               return Err(BlockSourceError::persistent("invalid merkle root"));
+                       }
 
-               if !self.check_witness_commitment() {
-                       return Err(BlockSourceError::persistent("invalid witness commitment"));
+                       if !block.check_witness_commitment() {
+                               return Err(BlockSourceError::persistent("invalid witness commitment"));
+                       }
                }
 
                Ok(ValidatedBlock { block_hash, inner: self })
@@ -94,9 +103,9 @@ impl Validate for Block {
 }
 
 /// A block header with validated proof of work and corresponding block hash.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct ValidatedBlockHeader {
-       block_hash: BlockHash,
+       pub(crate) block_hash: BlockHash,
        inner: BlockHeaderData,
 }
 
@@ -127,8 +136,11 @@ impl ValidatedBlockHeader {
 
                if let Network::Bitcoin = network {
                        if self.height % 2016 == 0 {
-                               let previous_work = previous_header.header.work();
-                               if work > (previous_work << 2) || work < (previous_work >> 2) {
+                               let target = self.header.target();
+                               let previous_target = previous_header.header.target();
+                               let min_target = previous_target.min_difficulty_transition_threshold();
+                               let max_target = previous_target.max_difficulty_transition_threshold();
+                               if target > max_target || target < min_target {
                                        return Err(BlockSourceError::persistent("invalid difficulty transition"))
                                }
                        } else if self.header.bits != previous_header.header.bits {
@@ -138,32 +150,53 @@ impl ValidatedBlockHeader {
 
                Ok(())
        }
+
+    /// Returns the [`BestBlock`] corresponding to this validated block header, which can be passed
+    /// into [`ChannelManager::new`] as part of its [`ChainParameters`]. Useful for ensuring that
+    /// the [`SpvClient`] and [`ChannelManager`] are initialized to the same block during a fresh
+    /// start.
+    ///
+    /// [`SpvClient`]: crate::SpvClient
+    /// [`ChainParameters`]: lightning::ln::channelmanager::ChainParameters
+    /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
+    /// [`ChannelManager::new`]: lightning::ln::channelmanager::ChannelManager::new
+    pub fn to_best_block(&self) -> BestBlock {
+        BestBlock::new(self.block_hash, self.inner.height)
+    }
 }
 
 /// A block with validated data against its transaction list and corresponding block hash.
 pub struct ValidatedBlock {
-       block_hash: BlockHash,
-       inner: Block,
+       pub(crate) block_hash: BlockHash,
+       inner: BlockData,
 }
 
 impl std::ops::Deref for ValidatedBlock {
-       type Target = Block;
+       type Target = BlockData;
 
        fn deref(&self) -> &Self::Target {
                &self.inner
        }
 }
 
+mod sealed {
+       /// Used to prevent implementing [`super::Validate`] outside the crate but still allow its use.
+       pub trait Validate {}
+
+       impl Validate for crate::BlockHeaderData {}
+       impl Validate for crate::BlockData {}
+}
+
 /// The canonical `Poll` implementation used for a single `BlockSource`.
 ///
-/// Other `Poll` implementations must be built using `ChainPoller` as it provides the only means of
-/// validating chain data.
-pub struct ChainPoller<B: DerefMut<Target=T> + Sized + Sync + Send, T: BlockSource> {
+/// Other `Poll` implementations should be built using `ChainPoller` as it provides the simplest way
+/// of validating chain data and checking consistency.
+pub struct ChainPoller<B: Deref<Target=T> + Sized + Send + Sync, T: BlockSource + ?Sized> {
        block_source: B,
        network: Network,
 }
 
-impl<B: DerefMut<Target=T> + Sized + Sync + Send, T: BlockSource> ChainPoller<B, T> {
+impl<B: Deref<Target=T> + Sized + Send + Sync, T: BlockSource + ?Sized> ChainPoller<B, T> {
        /// Creates a new poller for the given block source.
        ///
        /// If the `network` parameter is mainnet, then the difficulty between blocks is checked for
@@ -173,8 +206,8 @@ impl<B: DerefMut<Target=T> + Sized + Sync + Send, T: BlockSource> ChainPoller<B,
        }
 }
 
-impl<B: DerefMut<Target=T> + Sized + Sync + Send, T: BlockSource> Poll for ChainPoller<B, T> {
-       fn poll_chain_tip<'a>(&'a mut self, best_known_chain_tip: ValidatedBlockHeader) ->
+impl<B: Deref<Target=T> + Sized + Send + Sync, T: BlockSource + ?Sized> Poll for ChainPoller<B, T> {
+       fn poll_chain_tip<'a>(&'a self, best_known_chain_tip: ValidatedBlockHeader) ->
                AsyncBlockSourceResult<'a, ChainTip>
        {
                Box::pin(async move {
@@ -194,7 +227,7 @@ impl<B: DerefMut<Target=T> + Sized + Sync + Send, T: BlockSource> Poll for Chain
                })
        }
 
-       fn look_up_previous_header<'a>(&'a mut self, header: &'a ValidatedBlockHeader) ->
+       fn look_up_previous_header<'a>(&'a self, header: &'a ValidatedBlockHeader) ->
                AsyncBlockSourceResult<'a, ValidatedBlockHeader>
        {
                Box::pin(async move {
@@ -213,7 +246,7 @@ impl<B: DerefMut<Target=T> + Sized + Sync + Send, T: BlockSource> Poll for Chain
                })
        }
 
-       fn fetch_block<'a>(&'a mut self, header: &'a ValidatedBlockHeader) ->
+       fn fetch_block<'a>(&'a self, header: &'a ValidatedBlockHeader) ->
                AsyncBlockSourceResult<'a, ValidatedBlock>
        {
                Box::pin(async move {
@@ -229,7 +262,6 @@ mod tests {
        use crate::*;
        use crate::test_utils::Blockchain;
        use super::*;
-       use bitcoin::util::uint::Uint256;
 
        #[tokio::test]
        async fn poll_empty_chain() {
@@ -237,7 +269,7 @@ mod tests {
                let best_known_chain_tip = chain.tip();
                chain.disconnect_tip();
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => {
                                assert_eq!(e.kind(), BlockSourceErrorKind::Transient);
@@ -249,10 +281,10 @@ mod tests {
 
        #[tokio::test]
        async fn poll_chain_without_headers() {
-               let mut chain = Blockchain::default().with_height(1).without_headers();
+               let chain = Blockchain::default().with_height(1).without_headers();
                let best_known_chain_tip = chain.at_height(0);
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => {
                                assert_eq!(e.kind(), BlockSourceErrorKind::Persistent);
@@ -269,9 +301,9 @@ mod tests {
 
                // Invalidate the tip by changing its target.
                chain.blocks.last_mut().unwrap().header.bits =
-                       BlockHeader::compact_target_from_u256(&Uint256::from_be_bytes([0; 32]));
+                       bitcoin::Target::from_be_bytes([0x01; 32]).to_compact_lossy();
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => {
                                assert_eq!(e.kind(), BlockSourceErrorKind::Persistent);
@@ -283,10 +315,10 @@ mod tests {
 
        #[tokio::test]
        async fn poll_chain_with_malformed_headers() {
-               let mut chain = Blockchain::default().with_height(1).malformed_headers();
+               let chain = Blockchain::default().with_height(1).malformed_headers();
                let best_known_chain_tip = chain.at_height(0);
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => {
                                assert_eq!(e.kind(), BlockSourceErrorKind::Persistent);
@@ -298,10 +330,10 @@ mod tests {
 
        #[tokio::test]
        async fn poll_chain_with_common_tip() {
-               let mut chain = Blockchain::default().with_height(0);
+               let chain = Blockchain::default().with_height(0);
                let best_known_chain_tip = chain.tip();
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => panic!("Unexpected error: {:?}", e),
                        Ok(tip) => assert_eq!(tip, ChainTip::Common),
@@ -318,7 +350,7 @@ mod tests {
                let worse_chain_tip = chain.tip();
                assert_eq!(best_known_chain_tip.chainwork, worse_chain_tip.chainwork);
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => panic!("Unexpected error: {:?}", e),
                        Ok(tip) => assert_eq!(tip, ChainTip::Worse(worse_chain_tip)),
@@ -333,7 +365,7 @@ mod tests {
                chain.disconnect_tip();
                let worse_chain_tip = chain.tip();
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => panic!("Unexpected error: {:?}", e),
                        Ok(tip) => assert_eq!(tip, ChainTip::Worse(worse_chain_tip)),
@@ -342,12 +374,12 @@ mod tests {
 
        #[tokio::test]
        async fn poll_chain_with_better_tip() {
-               let mut chain = Blockchain::default().with_height(1);
+               let chain = Blockchain::default().with_height(1);
                let best_known_chain_tip = chain.at_height(0);
 
                let better_chain_tip = chain.tip();
 
-               let mut poller = ChainPoller::new(&mut chain, Network::Bitcoin);
+               let poller = ChainPoller::new(&chain, Network::Bitcoin);
                match poller.poll_chain_tip(best_known_chain_tip).await {
                        Err(e) => panic!("Unexpected error: {:?}", e),
                        Ok(tip) => assert_eq!(tip, ChainTip::Better(better_chain_tip)),