Merge pull request #4036 from ethcore/on-demand-les-request

On demand LES request

ethcore/light/src/net/mod.rs

@@ -30,6 +30,7 @@ use util::{Bytes, Mutex, RwLock, U256};
 use time::{Duration, SteadyTime};
 
 use std::collections::HashMap;
+use std::fmt;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
@@ -123,6 +124,12 @@ mod timeout {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct ReqId(usize);
 
+impl fmt::Display for ReqId {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(f, "Request #{}", self.0)
+	}
+}
+
 // A pending peer: one we've sent our status to but
 // may not have received one for.
 struct PendingPeer {
@@ -186,12 +193,12 @@ pub trait Handler: Send + Sync {
 	fn on_block_headers(&self, _ctx: &EventContext, _req_id: ReqId, _headers: &[Bytes]) { }
 	/// Called when a peer responds with block receipts.
 	fn on_receipts(&self, _ctx: &EventContext, _req_id: ReqId, _receipts: &[Vec<Receipt>]) { }
-	/// Called when a peer responds with state proofs. Each proof is a series of trie
+	/// Called when a peer responds with state proofs. Each proof should be a series of trie
 	/// nodes in ascending order by distance from the root.
 	fn on_state_proofs(&self, _ctx: &EventContext, _req_id: ReqId, _proofs: &[Vec<Bytes>]) { }
 	/// Called when a peer responds with contract code.
 	fn on_code(&self, _ctx: &EventContext, _req_id: ReqId, _codes: &[Bytes]) { }
-	/// Called when a peer responds with header proofs. Each proof is a block header coupled
+	/// Called when a peer responds with header proofs. Each proof should be a block header coupled
 	/// with a series of trie nodes is ascending order by distance from the root.
 	fn on_header_proofs(&self, _ctx: &EventContext, _req_id: ReqId, _proofs: &[(Bytes, Vec<Bytes>)]) { }
 	/// Called to "tick" the handler periodically.

ethcore/light/src/net/status.rs

@@ -158,6 +158,16 @@ pub struct Status {
 	pub last_head: Option<(H256, u64)>,
 }
 
+impl Status {
+	/// Update the status from an announcement.
+	pub fn update_from(&mut self, announcement: &Announcement) {
+		self.last_head = Some((self.head_hash, announcement.reorg_depth));
+		self.head_td = announcement.head_td;
+		self.head_hash = announcement.head_hash;
+		self.head_num = announcement.head_num;
+	}
+}
+
 /// Peer capabilities.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Capabilities {