Merge pull request #504 from ethcore/rpc_poll_ids

support for rpc polling

ethcore/src/client.rs

@@ -123,6 +123,9 @@ pub trait BlockChainClient : Sync + Send {
 	/// Get block total difficulty.
 	fn block_total_difficulty(&self, id: BlockId) -> Option<U256>;
 
+	/// Get block hash.
+	fn block_hash(&self, id: BlockId) -> Option<H256>;
+
 	/// Get address code.
 	fn code(&self, address: &Address) -> Option<Bytes>;
 
@@ -540,6 +543,11 @@ impl BlockChainClient for Client {
 		Self::block_hash(&chain, id).and_then(|hash| chain.block_details(&hash)).map(|d| d.total_difficulty)
 	}
 
+	fn block_hash(&self, id: BlockId) -> Option<H256> {
+		let chain = self.chain.read().unwrap();
+		Self::block_hash(&chain, id)
+	}
+
 	fn code(&self, address: &Address) -> Option<Bytes> {
 		self.state().code(address)
 	}

ethcore/src/filter.rs

@@ -42,6 +42,22 @@ pub struct Filter {
 	pub topics: [Option<Vec<H256>>; 4],
 }
 
+impl Clone for Filter {
+	fn clone(&self) -> Self {
+		let mut topics = [None, None, None, None];
+		for i in 0..4 {
+			topics[i] = self.topics[i].clone();
+		}
+
+		Filter {
+			from_block: self.from_block.clone(),
+			to_block: self.to_block.clone(),
+			address: self.address.clone(),
+			topics: topics
+		}
+	}
+}
+
 impl Filter {
 	/// Returns combinations of each address and topic.	
 	pub fn bloom_possibilities(&self) -> Vec<H2048> {