Merge branch 'master' into remote-tx-exec

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

@@ -20,7 +20,7 @@ use std::sync::Arc;
 
 use ethcore::block_import_error::BlockImportError;
 use ethcore::block_status::BlockStatus;
-use ethcore::client::ClientReport;
+use ethcore::client::{ClientReport, EnvInfo};
 use ethcore::engines::Engine;
 use ethcore::ids::BlockId;
 use ethcore::header::Header;
@@ -33,7 +33,7 @@ use io::IoChannel;
 
 use util::{Bytes, DBValue, H256, Mutex, RwLock};
 
-use self::header_chain::HeaderChain;
+use self::header_chain::{AncestryIter, HeaderChain};
 
 pub use self::service::Service;
 
@@ -62,6 +62,12 @@ 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>;
+
 	/// Query whether a block is known.
 	fn is_known(&self, hash: &H256) -> bool;
 
@@ -164,6 +170,16 @@ 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())
+	}
+
 	/// Flush the header queue.
 	pub fn flush_queue(&self) {
 		self.queue.flush()
@@ -217,6 +233,33 @@ impl Client {
 	pub fn engine(&self) -> &Engine {
 		&*self.engine
 	}
+
+	fn latest_env_info(&self) -> EnvInfo {
+		let header = self.best_block_header();
+
+		EnvInfo {
+			number: header.number(),
+			author: header.author(),
+			timestamp: header.timestamp(),
+			difficulty: header.difficulty(),
+			last_hashes: self.build_last_hashes(header.hash()),
+			gas_used: Default::default(),
+			gas_limit: header.gas_limit(),
+		}
+	}
+
+	fn build_last_hashes(&self, mut parent_hash: H256) -> Arc<Vec<H256>> {
+		let mut v = Vec::with_capacity(256);
+		for _ in 0..255 {
+			v.push(parent_hash);
+			match self.block_header(BlockId::Hash(parent_hash)) {
+				Some(header) => parent_hash = header.hash(),
+				None => break,
+			}
+		}
+
+		Arc::new(v)
+	}
 }
 
 impl LightChainClient for Client {
@@ -234,6 +277,14 @@ 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)
+	}
+
 	fn is_known(&self, hash: &H256) -> bool {
 		self.status(hash) == BlockStatus::InChain
 	}