get_alternate_chains

binaries/cuprated/src/rpc/json.rs

@@ -41,7 +41,7 @@ use cuprate_rpc_types::{
         SetBansRequest, SetBansResponse, SubmitBlockRequest, SubmitBlockResponse, SyncInfoRequest,
         SyncInfoResponse,
     },
-    misc::{BlockHeader, GetBan, HardforkEntry, HistogramEntry, Status},
+    misc::{BlockHeader, ChainInfo, GetBan, HardforkEntry, HistogramEntry, Status},
     CORE_RPC_VERSION,
 };
 
@@ -617,12 +617,32 @@ async fn get_fee_estimate(
 
 /// <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server.cpp#L3033-L3064>
 async fn get_alternate_chains(
-    state: CupratedRpcHandler,
+    mut state: CupratedRpcHandler,
     request: GetAlternateChainsRequest,
 ) -> Result<GetAlternateChainsResponse, Error> {
+    let chains = blockchain::alt_chains(&mut state.blockchain_read)
+        .await?
+        .into_iter()
+        .map(|info| {
+            let block_hashes = info.block_hashes.into_iter().map(hex::encode).collect();
+            let (difficulty, difficulty_top64) = split_u128_into_low_high_bits(info.difficulty);
+
+            ChainInfo {
+                block_hash: hex::encode(info.block_hash),
+                block_hashes,
+                difficulty,
+                difficulty_top64,
+                height: info.height,
+                length: info.length,
+                main_chain_parent_block: hex::encode(info.main_chain_parent_block),
+                wide_difficulty: hex::encode(u128::to_ne_bytes(info.difficulty)),
+            }
+        })
+        .collect();
+
     Ok(GetAlternateChainsResponse {
         base: ResponseBase::ok(),
-        chains: todo!(),
+        chains,
     })
 }
 

binaries/cuprated/src/rpc/request/blockchain.rs

@@ -9,12 +9,12 @@ use anyhow::Error;
 use monero_serai::block::Block;
 use tower::{Service, ServiceExt};
 
-use cuprate_blockchain::service::BlockchainReadHandle;
+use cuprate_blockchain::{service::BlockchainReadHandle, types::AltChainInfo};
 use cuprate_helper::cast::{u64_to_usize, usize_to_u64};
 use cuprate_types::{
     blockchain::{BlockchainReadRequest, BlockchainResponse},
-    Chain, CoinbaseTxSum, ExtendedBlockHeader, HardFork, MinerData, OutputHistogramEntry,
-    OutputHistogramInput, OutputOnChain,
+    Chain, ChainInfo, CoinbaseTxSum, ExtendedBlockHeader, HardFork, MinerData,
+    OutputHistogramEntry, OutputHistogramInput, OutputOnChain,
 };
 
 /// [`BlockchainReadRequest::Block`].
@@ -359,3 +359,19 @@ pub(crate) async fn hard_forks(
 
     Ok(hfs)
 }
+
+/// [`BlockchainReadRequest::AltChains`]
+pub(crate) async fn alt_chains(
+    blockchain_read: &mut BlockchainReadHandle,
+) -> Result<Vec<ChainInfo>, Error> {
+    let BlockchainResponse::AltChains(vec) = blockchain_read
+        .ready()
+        .await?
+        .call(BlockchainReadRequest::AltChains)
+        .await?
+    else {
+        unreachable!();
+    };
+
+    Ok(vec)
+}

storage/blockchain/src/service/read.rs

@@ -122,6 +122,7 @@ fn map_request(
         R::OutputHistogram(input) => output_histogram(env, input),
         R::CoinbaseTxSum { height, count } => coinbase_tx_sum(env, height, count),
         R::HardForks => hard_forks(env),
+        R::AltChains => alt_chains(env),
     }
 
     /* SOMEDAY: post-request handling, run some code for each request? */
@@ -654,3 +655,8 @@ fn coinbase_tx_sum(env: &ConcreteEnv, height: usize, count: u64) -> ResponseResu
 fn hard_forks(env: &ConcreteEnv) -> ResponseResult {
     Ok(BlockchainResponse::HardForks(todo!()))
 }
+
+/// [`BlockchainReadRequest::AltChains`]
+fn alt_chains(env: &ConcreteEnv) -> ResponseResult {
+    Ok(BlockchainResponse::AltChains(todo!()))
+}

types/src/blockchain.rs

@@ -12,7 +12,7 @@ use monero_serai::block::Block;
 
 use crate::{
     types::{Chain, ExtendedBlockHeader, OutputOnChain, VerifiedBlockInformation},
-    AltBlockInformation, ChainId, CoinbaseTxSum, HardFork, OutputHistogramEntry,
+    AltBlockInformation, ChainId, ChainInfo, CoinbaseTxSum, HardFork, OutputHistogramEntry,
     OutputHistogramInput,
 };
 
@@ -108,9 +108,7 @@ pub enum BlockchainReadRequest {
     AltBlocksInChain(ChainId),
 
     /// Get a [`Block`] by its height.
-    Block {
-        height: usize,
-    },
+    Block { height: usize },
 
     /// Get a [`Block`] by its hash.
     BlockByHash([u8; 32]),
@@ -130,12 +128,13 @@ pub enum BlockchainReadRequest {
     /// `N` last blocks starting at particular height.
     ///
     /// TODO: document fields after impl.
-    CoinbaseTxSum {
-        height: usize,
-        count: u64,
-    },
+    CoinbaseTxSum { height: usize, count: u64 },
 
+    /// TODO
     HardForks,
+
+    /// TODO
+    AltChains,
 }
 
 //---------------------------------------------------------------------------------------------------- WriteRequest
@@ -290,6 +289,8 @@ pub enum BlockchainResponse {
     /// - Value = hardfork version
     HardForks(BTreeMap<usize, HardFork>),
 
+    AltChains(Vec<ChainInfo>),
+
     //------------------------------------------------------ Writes
     /// A generic Ok response to indicate a request was successfully handled.
     ///

types/src/types.rs

@@ -240,7 +240,6 @@ pub struct ChainInfo {
     pub height: u64,
     pub length: u64,
     pub main_chain_parent_block: [u8; 32],
-    pub wide_difficulty: u128,
 }
 
 //---------------------------------------------------------------------------------------------------- Tests