Add chain_getShardRoot RPC

Author: Seulgi Kim

core/src/client/client.rs

@@ -866,6 +866,14 @@ impl Shard for Client {
         };
         state.number_of_shards().ok()
     }
+
+    fn shard_root(&self, shard_id: u32, state: StateOrBlock) -> Option<H256> {
+        let state = match state {
+            StateOrBlock::State(s) => s,
+            StateOrBlock::Block(id) => Box::new(self.state_at(id)?),
+        };
+        state.shard_root(shard_id).ok()?
+    }
 }
 
 impl ReopenBlock for Client {

core/src/client/mod.rs

@@ -140,6 +140,8 @@ pub trait RegularKey {
 
 pub trait Shard {
     fn number_of_shards(&self, state: StateOrBlock) -> Option<u32>;
+
+    fn shard_root(&self, shard_id: u32, state: StateOrBlock) -> Option<H256>;
 }
 
 /// Provides methods to access account info

rpc/src/v1/impls/chain.rs

@@ -113,6 +113,11 @@ impl Chain for ChainClient {
         Ok(self.client.number_of_shards(block_id.into()))
     }
 
+    fn get_shard_root(&self, shard_id: u32, block_number: Option<u64>) -> Result<Option<H256>> {
+        let block_id = block_number.map(BlockId::Number).unwrap_or(BlockId::Latest);
+        Ok(self.client.shard_root(shard_id, 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

@@ -63,6 +63,10 @@ build_rpc_trait! {
         # [rpc(name = "chain_getNumberOfShards")]
         fn get_number_of_shards(&self, Option<u64>) -> Result<Option<u32>>;
 
+        /// Gets shard root
+        # [rpc(name = "chain_getShardRoot")]
+        fn get_shard_root(&self, u32, Option<u64>) -> Result<Option<H256>>;
+
         /// Gets number of best block.
         # [rpc(name = "chain_getBestBlockNumber")]
         fn get_best_block_number(&self) -> Result<BlockNumber>;

spec/JSON-RPC.md

@@ -94,6 +94,7 @@ In the current version, it's only supported through HTTP.
  * [chain_getBalance](#chain_getbalance)
  * [chain_getRegularKey](#chain_getregularkey)
  * [chain_getNumberOfShards](#chain_getnumberofshards)
+ * [chain_getShardRoot](#chain_getshardroot)
  * [chain_getPendingParcels](#chain_getpendingparcels)
 ***
   * [miner_getWork](#miner_getwork)
@@ -487,6 +488,28 @@ Response Example
 {"jsonrpc":"2.0","result":3,"id":null}
 ```
 
+## chain_getShardRoot
+Gets the root of shard, at state of given blockNumber.
+
+Param:
+1. shard id: `number`
+1. block number: `number` or `null`
+
+Return Type: `null` or `string` - the root of shard
+
+Request Example
+```
+  curl \
+    -H 'Content-Type: application/json' \
+    -d '{"jsonrpc": "2.0", "method": "chain_getShardRoot", "params": [1, null], "id": null}' \
+    localhost:8080
+```
+
+Response Example
+```
+{"jsonrpc":"2.0","result":"0xf3841adc1615bfeabb801dda23585c1722b80d810df084a5f2198e92285d4bfd","id":null}
+```
+
 
 ## chain_getPendingParcels
 Gets parcels in the current parcel queue.