enums instead of bools

binaries/cuprated/src/blockchain/interface.rs

@@ -4,13 +4,13 @@
 //! blockchain manager.
 use std::{
     collections::{HashMap, HashSet},
-    sync::{Mutex, OnceLock, LazyLock},
+    sync::{LazyLock, Mutex, OnceLock},
 };
 
-use tokio::sync::{mpsc, oneshot};
-use tower::{Service, ServiceExt};
 use monero_serai::{block::Block, transaction::Transaction};
 use rayon::prelude::*;
+use tokio::sync::{mpsc, oneshot};
+use tower::{Service, ServiceExt};
 
 use cuprate_blockchain::service::BlockchainReadHandle;
 use cuprate_consensus::transactions::new_tx_verification_data;
@@ -21,12 +21,14 @@ use cuprate_types::{
 };
 
 use crate::{
-    blockchain::manager::BlockchainManagerCommand, constants::PANIC_CRITICAL_SERVICE_ERROR,
+    blockchain::manager::{BlockchainManagerCommand, IncomingBlockOk},
+    constants::PANIC_CRITICAL_SERVICE_ERROR,
 };
 
 /// The channel used to send [`BlockchainManagerCommand`]s to the blockchain manager.
 ///
-/// This channel is initialized in [`init_blockchain_manager`](super::manager::init_blockchain_manager).
+/// This channel is initialized in [`init_blockchain_manager`](super::manager::init_blockchain_manager), the functions
+/// in this file document what happens if this is not initialized when they are called.
 pub(super) static COMMAND_TX: OnceLock<mpsc::Sender<BlockchainManagerCommand>> = OnceLock::new();
 
 /// An error that can be returned from [`handle_incoming_block`].
@@ -62,7 +64,7 @@ pub async fn handle_incoming_block(
     block: Block,
     given_txs: Vec<Transaction>,
     blockchain_read_handle: &mut BlockchainReadHandle,
-) -> Result<bool, IncomingBlockError> {
+) -> Result<IncomingBlockOk, IncomingBlockError> {
     /// A [`HashSet`] of block hashes that the blockchain manager is currently handling.
     ///
     /// This lock prevents sending the same block to the blockchain manager from multiple connections
@@ -88,7 +90,7 @@ pub async fn handle_incoming_block(
         .await
         .expect(PANIC_CRITICAL_SERVICE_ERROR)
     {
-        return Ok(false);
+        return Ok(IncomingBlockOk::AlreadyHave);
     }
 
     // TODO: remove this when we have a working tx-pool.
@@ -110,15 +112,14 @@ pub async fn handle_incoming_block(
         .map_err(IncomingBlockError::InvalidBlock)?;
 
     let Some(incoming_block_tx) = COMMAND_TX.get() else {
-        // We could still be starting up the blockchain manager, so just return this as there is nothing
-        // else we can do.
-        return Ok(false);
+        // We could still be starting up the blockchain manager.
+        return Ok(IncomingBlockOk::NotReady);
     };
 
     // Add the blocks hash to the blocks being handled.
     if !BLOCKS_BEING_HANDLED.lock().unwrap().insert(block_hash) {
         // If another place is already adding this block then we can stop.
-        return Ok(false);
+        return Ok(IncomingBlockOk::AlreadyHave);
     }
 
     // From this point on we MUST not early return without removing the block hash from `BLOCKS_BEING_HANDLED`.

binaries/cuprated/src/blockchain/manager.rs

@@ -35,7 +35,7 @@ use crate::{
 mod commands;
 mod handler;
 
-pub use commands::BlockchainManagerCommand;
+pub use commands::{BlockchainManagerCommand, IncomingBlockOk};
 
 /// Initialize the blockchain manager.
 ///

binaries/cuprated/src/blockchain/manager/commands.rs

@@ -15,6 +15,18 @@ pub enum BlockchainManagerCommand {
         /// All the transactions defined in [`Block::transactions`].
         prepped_txs: HashMap<[u8; 32], TransactionVerificationData>,
         /// The channel to send the response down.
-        response_tx: oneshot::Sender<Result<bool, anyhow::Error>>,
+        response_tx: oneshot::Sender<Result<IncomingBlockOk, anyhow::Error>>,
     },
 }
+
+/// The [`Ok`] response for an incoming block.
+pub enum IncomingBlockOk {
+    /// The block was added to the main-chain.
+    AddedToMainChain,
+    /// The blockchain manager is not ready yet.
+    NotReady,
+    /// The block was added to an alt-chain.
+    AddedToAltChain,
+    /// We already have the block.
+    AlreadyHave,
+}

binaries/cuprated/src/blockchain/manager/handler.rs

@@ -1,10 +1,10 @@
 //! The blockchain manager handler functions.
-use std::{collections::HashMap, sync::Arc};
-
 use bytes::Bytes;
 use futures::{TryFutureExt, TryStreamExt};
 use monero_serai::{block::Block, transaction::Transaction};
 use rayon::prelude::*;
+use std::ops::ControlFlow;
+use std::{collections::HashMap, sync::Arc};
 use tower::{Service, ServiceExt};
 use tracing::info;
 
@@ -22,6 +22,7 @@ use cuprate_types::{
     AltBlockInformation, HardFork, TransactionVerificationData, VerifiedBlockInformation,
 };
 
+use crate::blockchain::manager::commands::IncomingBlockOk;
 use crate::{
     blockchain::{
         manager::commands::BlockchainManagerCommand, types::ConsensusBlockchainReadHandle,
@@ -73,11 +74,10 @@ impl super::BlockchainManager {
         &mut self,
         block: Block,
         prepared_txs: HashMap<[u8; 32], TransactionVerificationData>,
-    ) -> Result<bool, anyhow::Error> {
+    ) -> Result<IncomingBlockOk, anyhow::Error> {
         if block.header.previous != self.cached_blockchain_context.top_hash {
             self.handle_incoming_alt_block(block, prepared_txs).await?;
-
-            return Ok(false);
+            return Ok(IncomingBlockOk::AddedToAltChain);
         }
 
         let VerifyBlockResponse::MainChain(verified_block) = self
@@ -91,7 +91,7 @@ impl super::BlockchainManager {
             })
             .await?
         else {
-            panic!("Incorrect response!");
+            unreachable!();
         };
 
         let block_blob = Bytes::copy_from_slice(&verified_block.block_blob);
@@ -100,7 +100,7 @@ impl super::BlockchainManager {
         self.broadcast_block(block_blob, self.cached_blockchain_context.chain_height)
             .await;
 
-        Ok(true)
+        Ok(IncomingBlockOk::AddedToMainChain)
     }
 
     /// Handle an incoming [`BlockBatch`].
@@ -160,7 +160,7 @@ impl super::BlockchainManager {
                 self.stop_current_block_downloader.notify_one();
                 return;
             }
-            _ => panic!("Incorrect response!"),
+            _ => unreachable!(),
         };
 
         for (block, txs) in prepped_blocks {
@@ -179,7 +179,7 @@ impl super::BlockchainManager {
                     self.stop_current_block_downloader.notify_one();
                     return;
                 }
-                _ => panic!("Incorrect response!"),
+                _ => unreachable!(),
             };
 
             self.add_valid_block_to_main_chain(verified_block).await;
@@ -226,16 +226,14 @@ impl super::BlockchainManager {
                     self.stop_current_block_downloader.notify_one();
                     return;
                 }
-                // the chain was reorged
-                Ok(true) => {
+                Ok(AddAltBlock::Reorged) => {
                     // Collect the remaining blocks and add them to the main chain instead.
                     batch.blocks = blocks.collect();
                     self.handle_incoming_block_batch_main_chain(batch).await;
-
                     return;
                 }
                 // continue adding alt blocks.
-                Ok(false) => (),
+                Ok(AddAltBlock::Cached) => (),
             }
         }
     }
@@ -258,11 +256,11 @@ impl super::BlockchainManager {
     ///
     /// This function will panic if any internal service returns an unexpected error that we cannot
     /// recover from.
-    pub async fn handle_incoming_alt_block(
+    async fn handle_incoming_alt_block(
         &mut self,
         block: Block,
         prepared_txs: HashMap<[u8; 32], TransactionVerificationData>,
-    ) -> Result<bool, anyhow::Error> {
+    ) -> Result<AddAltBlock, anyhow::Error> {
         let VerifyBlockResponse::AltChain(alt_block_info) = self
             .block_verifier_service
             .ready()
@@ -274,7 +272,7 @@ impl super::BlockchainManager {
             })
             .await?
         else {
-            panic!("Incorrect response!");
+            unreachable!();
         };
 
         // TODO: check in consensus crate if alt block with this hash already exists.
@@ -284,7 +282,7 @@ impl super::BlockchainManager {
             > self.cached_blockchain_context.cumulative_difficulty
         {
             self.try_do_reorg(alt_block_info).await?;
-            return Ok(true);
+            return Ok(AddAltBlock::Reorged);
         }
 
         self.blockchain_write_handle
@@ -294,7 +292,7 @@ impl super::BlockchainManager {
             .call(BlockchainWriteRequest::WriteAltBlock(alt_block_info))
             .await?;
 
-        Ok(false)
+        Ok(AddAltBlock::Cached)
     }
 
     /// Attempt a re-org with the given top block of the alt-chain.
@@ -328,7 +326,7 @@ impl super::BlockchainManager {
             ))
             .await?
         else {
-            panic!("Incorrect response!");
+            unreachable!();
         };
 
         alt_blocks.push(top_alt_block);
@@ -347,7 +345,7 @@ impl super::BlockchainManager {
             .await
             .expect(PANIC_CRITICAL_SERVICE_ERROR)
         else {
-            panic!("Incorrect response!");
+            unreachable!();
         };
 
         self.blockchain_context_service
@@ -409,7 +407,7 @@ impl super::BlockchainManager {
                 })
                 .await?
             else {
-                panic!("Incorrect response!");
+                unreachable!();
             };
 
             self.add_valid_block_to_main_chain(verified_block).await;
@@ -465,9 +463,17 @@ impl super::BlockchainManager {
             .await
             .expect(PANIC_CRITICAL_SERVICE_ERROR)
         else {
-            panic!("Incorrect response!");
+            unreachable!();
         };
 
         self.cached_blockchain_context = blockchain_context.unchecked_blockchain_context().clone();
     }
 }
+
+/// The result from successfully adding an alt-block.
+enum AddAltBlock {
+    /// The alt-block was cached.
+    Cached,
+    /// The chain was reorged.
+    Reorged,
+}