fetch gas price corpus from network when needed

ethcore/light/Cargo.toml

@@ -23,6 +23,7 @@ smallvec = "0.3.1"
 futures = "0.1"
 rand = "0.3"
 itertools = "0.5"
+stats = { path = "../../util/stats" }
 
 [features]
 default = []

ethcore/light/src/cache.rs

@@ -24,6 +24,7 @@ use ethcore::encoded;
 use ethcore::header::BlockNumber;
 use ethcore::receipt::Receipt;
 
+use stats::Corpus;
 use time::{SteadyTime, Duration};
 use util::{U256, H256};
 use util::cache::MemoryLruCache;
@@ -66,7 +67,7 @@ pub struct Cache {
 	bodies: MemoryLruCache<H256, encoded::Body>,
 	receipts: MemoryLruCache<H256, Vec<Receipt>>,
 	chain_score: MemoryLruCache<H256, U256>,
-	corpus: Option<(Vec<U256>, SteadyTime)>,
+	corpus: Option<(Corpus<U256>, SteadyTime)>,
 	corpus_expiration: Duration,
 }
 
@@ -135,7 +136,7 @@ impl Cache {
 	}
 
 	/// Get gas price corpus, if recent enough.
-	pub fn gas_price_corpus(&self) -> Option<Vec<U256>> {
+	pub fn gas_price_corpus(&self) -> Option<Corpus<U256>> {
 		let now = SteadyTime::now();
 
 		self.corpus.as_ref().and_then(|&(ref corpus, ref tm)| {
@@ -148,7 +149,7 @@ impl Cache {
 	}
 
 	/// Set the cached gas price corpus.
-	pub fn set_gas_price_corpus(&mut self, corpus: Vec<U256>) {
+	pub fn set_gas_price_corpus(&mut self, corpus: Corpus<U256>) {
 		self.corpus = Some((corpus, SteadyTime::now()))
 	}
 }
@@ -162,8 +163,8 @@ mod tests {
 	fn corpus_inaccessible() {
 		let mut cache = Cache::new(Default::default(), Duration::hours(5));
 
-		cache.set_gas_price_corpus(vec![]);
-		assert_eq!(cache.gas_price_corpus(), Some(vec![]));
+		cache.set_gas_price_corpus(vec![].into());
+		assert_eq!(cache.gas_price_corpus(), Some(vec![].into()));
 
 		{
 			let corpus_time = &mut cache.corpus.as_mut().unwrap().1;

ethcore/light/src/client/header_chain.rs

@@ -241,6 +241,14 @@ impl HeaderChain {
 		self.block_header(BlockId::Latest).expect("Header for best block always stored; qed")
 	}
 
+	/// Get an iterator over a block and its ancestry.
+	pub fn ancestry_iter(&self, start: BlockId) -> AncestryIter {
+		AncestryIter {
+			next: self.block_header(start),
+			chain: self,
+		}
+	}
+
 	/// Get the nth CHT root, if it's been computed.
 	///
 	/// CHT root 0 is from block `1..2048`.
@@ -295,6 +303,25 @@ impl HeapSizeOf for HeaderChain {
 	}
 }
 
+/// Iterator over a block's ancestry.
+pub struct AncestryIter<'a> {
+	next: Option<encoded::Header>,
+	chain: &'a HeaderChain,
+}
+
+impl<'a> Iterator for AncestryIter<'a> {
+	type Item = encoded::Header;
+
+	fn next(&mut self) -> Option<encoded::Header> {
+		let next = self.next.take();
+		if let Some(p_hash) = next.as_ref().map(|hdr| hdr.parent_hash()) {
+			self.next = self.chain.block_header(BlockId::Hash(p_hash));
+		}
+
+		next
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::HeaderChain;

ethcore/light/src/client/mod.rs

@@ -33,7 +33,7 @@ use io::IoChannel;
 
 use util::{Bytes, H256, Mutex, RwLock};
 
-use self::header_chain::HeaderChain;
+use self::header_chain::{AncestryIter, HeaderChain};
 
 pub use self::service::Service;
 
@@ -62,6 +62,9 @@ pub trait LightChainClient: Send + Sync {
 	/// Get the best block header.
 	fn best_block_header(&self) -> encoded::Header;
 
+	/// Get an iterator over a block and its ancestry.
+	fn ancestry_iter<'a>(&'a self, start: BlockId) -> Box<Iterator<Item=encoded::Header> + 'a>;
+
 	/// Get the signing network ID.
 	fn signing_network_id(&self) -> Option<u64>;
 
@@ -167,6 +170,11 @@ impl Client {
 		self.chain.best_header()
 	}
 
+	/// Get an iterator over a block and its ancestry.
+	pub fn ancestry_iter(&self, start: BlockId) -> AncestryIter {
+		self.chain.ancestry_iter(start)
+	}
+
 	/// Get the signing network id.
 	pub fn signing_network_id(&self) -> Option<u64> {
 		self.engine.signing_network_id(&self.latest_env_info())
@@ -269,6 +277,10 @@ impl LightChainClient for Client {
 		Client::best_block_header(self)
 	}
 
+	fn ancestry_iter<'a>(&'a self, start: BlockId) -> Box<Iterator<Item=encoded::Header> + 'a> {
+		Box::new(Client::ancestry_iter(self, start))
+	}
+
 	fn signing_network_id(&self) -> Option<u64> {
 		Client::signing_network_id(self)
 	}

ethcore/light/src/lib.rs

@@ -72,6 +72,7 @@ extern crate time;
 extern crate futures;
 extern crate rand;
 extern crate itertools;
+extern crate stats;
 
 #[cfg(feature = "ipc")]
 extern crate ethcore_ipc as ipc;