Add chain_getNumberOfShards RPC

Author: Seulgi Kim

core/src/client/client.rs

@@ -54,7 +54,7 @@ use super::{
     AccountData, Balance, BlockChain as BlockChainTrait, BlockChainClient, BlockChainInfo, BlockInfo, BlockProducer,
     ChainInfo, ChainNotify, ClientConfig, EngineClient, Error as ClientError, ImportBlock, ImportResult,
     ImportSealedBlock, Invoice, MiningBlockChainClient, Nonce, ParcelInfo, PrepareOpenBlock, RegularKey, ReopenBlock,
-    StateOrBlock,
+    Shard, StateOrBlock,
 };
 
 const MAX_MEM_POOL_SIZE: usize = 4096;
@@ -858,6 +858,16 @@ impl RegularKey for Client {
     }
 }
 
+impl Shard for Client {
+    fn number_of_shards(&self, state: StateOrBlock) -> Option<u32> {
+        let state = match state {
+            StateOrBlock::State(s) => s,
+            StateOrBlock::Block(id) => Box::new(self.state_at(id)?),
+        };
+        state.number_of_shards().ok()
+    }
+}
+
 impl ReopenBlock for Client {
     fn reopen_block(&self, block: ClosedBlock) -> OpenBlock {
         let engine = &*self.engine;

core/src/client/mod.rs

@@ -138,6 +138,10 @@ pub trait RegularKey {
     fn regular_key(&self, address: &Address, state: StateOrBlock) -> Option<Public>;
 }
 
+pub trait Shard {
+    fn number_of_shards(&self, state: StateOrBlock) -> Option<u32>;
+}
+
 /// Provides methods to access account info
 pub trait AccountData: Nonce + Balance {}
 

core/src/client/test_client.rs

@@ -445,6 +445,10 @@ impl TopStateInfo for () {
         unimplemented!()
     }
 
+    fn number_of_shards(&self) -> trie::Result<u32> {
+        unimplemented!()
+    }
+
     fn shard_root(&self, _shard_id: u32) -> trie::Result<Option<H256>> {
         unimplemented!()
     }

core/src/lib.rs

@@ -90,7 +90,7 @@ pub use account_provider::AccountProvider;
 pub use block::Block;
 pub use blockchain::ParcelInvoice;
 pub use client::{
-    Balance, BlockChainClient, BlockInfo, ChainInfo, ChainNotify, Client, ImportBlock, Nonce, RegularKey,
+    Balance, BlockChainClient, BlockInfo, ChainInfo, ChainNotify, Client, ImportBlock, Nonce, RegularKey, Shard,
     TestBlockChainClient,
 };
 pub use db::COL_STATE;

core/src/state/info.rs

@@ -29,6 +29,8 @@ pub trait TopStateInfo {
     /// Get the regular key of account `a`.
     fn regular_key(&self, a: &Address) -> TrieResult<Option<Public>>;
 
+    fn number_of_shards(&self) -> TrieResult<u32>;
+
     fn shard_root(&self, shard_id: u32) -> TrieResult<Option<H256>>;
 
     /// Get the asset scheme.

core/src/state/top_level.rs

@@ -136,6 +136,10 @@ impl<B: Backend + TopBackend + ShardBackend + Clone> TopStateInfo for TopLevelSt
         self.ensure_account_cached(a, |a| a.as_ref().map_or(None, |account| account.regular_key()))
     }
 
+    fn number_of_shards(&self) -> TrieResult<u32> {
+        let metadata = self.require_metadata()?;
+        Ok(*metadata.number_of_shards())
+    }
 
     fn shard_root(&self, shard_id: u32) -> TrieResult<Option<H256>> {
         let shard_address = ShardAddress::new(shard_id);

rpc/src/v1/impls/chain.rs

@@ -18,7 +18,8 @@ use std::sync::Arc;
 
 use ccore::{
     Asset, AssetAddress, AssetScheme, AssetSchemeAddress, Balance, BlockChainClient, BlockId, BlockInfo, BlockNumber,
-    ChainInfo, Client, Invoice, Miner, MinerService, Nonce, ParcelInvoice, RegularKey, SignedParcel, TopStateInfo,
+    ChainInfo, Client, Invoice, Miner, MinerService, Nonce, ParcelInvoice, RegularKey, Shard, SignedParcel,
+    TopStateInfo,
 };
 use ctypes::{H160, H256, Public, U256};
 use rlp::UntrustedRlp;
@@ -106,6 +107,12 @@ impl Chain for ChainClient {
         Ok(self.client.regular_key(&address.into(), block_id.into()))
     }
 
+
+    fn get_number_of_shards(&self, block_number: Option<u64>) -> Result<Option<u32>> {
+        let block_id = block_number.map(BlockId::Number).unwrap_or(BlockId::Latest);
+        Ok(self.client.number_of_shards(block_id.into()))
+    }
+
     fn get_best_block_number(&self) -> Result<BlockNumber> {
         Ok(self.client.chain_info().best_block_number)
     }

rpc/src/v1/traits/chain.rs

@@ -59,6 +59,10 @@ build_rpc_trait! {
         # [rpc(name = "chain_getRegularKey")]
         fn get_regular_key(&self, H160, Option<u64>) -> Result<Option<Public>>;
 
+        /// Gets the number of shards
+        # [rpc(name = "chain_getNumberOfShards")]
+        fn get_number_of_shards(&self, Option<u64>) -> Result<Option<u32>>;
+
         /// Gets number of best block.
         # [rpc(name = "chain_getBestBlockNumber")]
         fn get_best_block_number(&self) -> Result<BlockNumber>;

spec/JSON-RPC.md

@@ -93,6 +93,7 @@ In the current version, it's only supported through HTTP.
  * [chain_getNonce](#chain_getnonce)
  * [chain_getBalance](#chain_getbalance)
  * [chain_getRegularKey](#chain_getregularkey)
+ * [chain_getNumberOfShards](#chain_getnumberofshards)
  * [chain_getPendingParcels](#chain_getpendingparcels)
 ***
   * [miner_getWork](#miner_getwork)
@@ -465,6 +466,28 @@ Response Example
 {"jsonrpc":"2.0","result":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","id":null}
 ```
 
+## chain_getNumberOfShards
+Gets the number of shards, at state of given blockNumber.
+
+Param:
+1. block number: `number` or `null`
+
+Return Type: `number` - the number of shards
+
+Request Example
+```
+  curl \
+    -H 'Content-Type: application/json' \
+    -d '{"jsonrpc": "2.0", "method": "chain_getNumberOfShards", "params": [null], "id": null}' \
+    localhost:8080
+```
+
+Response Example
+```
+{"jsonrpc":"2.0","result":3,"id":null}
+```
+
+
 ## chain_getPendingParcels
 Gets parcels in the current parcel queue.