implement header queue

ethcore/src/verification/queue/kind.rs

@@ -22,6 +22,7 @@ use error::Error;
 use util::{HeapSizeOf, H256};
 
 pub use self::blocks::Blocks;
+pub use self::headers::Headers;
 
 /// Something which can produce a hash and a parent hash.
 pub trait HasHash {
@@ -144,4 +145,38 @@ pub mod blocks {
 			self.header.parent_hash().clone()
 		}
 	}
+}
+
+/// Verification for headers.
+pub mod headers {
+	use super::{Kind, HasHash};
+
+	use engines::Engine;
+	use error::Error;
+	use header::Header;
+	use verification::verify_header_params;
+
+	use util::hash::H256;
+
+	impl HasHash for Header {
+		fn hash(&self) -> H256 { self.hash() }
+		fn parent_hash(&self) -> H256 { self.parent_hash().clone() }
+	}
+
+	/// A mode for verifying headers.
+	pub struct Headers;
+
+	impl Kind for Headers {
+		type Input = Header;
+		type Unverified = Header;
+		type Verified = Header;
+
+		fn create(input: Self::Input, engine: &Engine) -> Result<Self::Unverified, Error> {
+			verify_header_params(&input, engine).map(|_| input)
+		}
+
+		fn verify(unverified: Self::Unverified, engine: &Engine) -> Result<Self::Verified, Error> {
+			engine.verify_block_unordered(&unverified, None).map(|_| unverified)
+		}
+	}
 }

ethcore/src/verification/queue/mod.rs

@@ -38,6 +38,9 @@ const MIN_QUEUE_LIMIT: usize = 512;
 /// Type alias for block queue convenience.
 pub type BlockQueue = VerificationQueue<self::kind::Blocks>;
 
+/// Type alias for header queue convenience.
+pub type HeaderQueue = VerificationQueue<self::kind::Headers>;
+
 /// Verification queue configuration
 #[derive(Debug, PartialEq, Clone)]
 pub struct Config {

ethcore/src/verification/verification.rs

@@ -46,12 +46,12 @@ impl HeapSizeOf for PreverifiedBlock {
 
 /// Phase 1 quick block verification. Only does checks that are cheap. Operates on a single block
 pub fn verify_block_basic(header: &Header, bytes: &[u8], engine: &Engine) -> Result<(), Error> {
-	try!(verify_header(&header, engine));
+	try!(verify_header_params(&header, engine));
 	try!(verify_block_integrity(bytes, &header.transactions_root(), &header.uncles_hash()));
 	try!(engine.verify_block_basic(&header, Some(bytes)));
 	for u in try!(UntrustedRlp::new(bytes).at(2)).iter().map(|rlp| rlp.as_val::<Header>()) {
 		let u = try!(u);
-		try!(verify_header(&u, engine));
+		try!(verify_header_params(&u, engine));
 		try!(engine.verify_block_basic(&u, None));
 	}
 	// Verify transactions.
@@ -187,7 +187,7 @@ pub fn verify_block_final(expected: &Header, got: &Header) -> Result<(), Error>
 }
 
 /// Check basic header parameters.
-fn verify_header(header: &Header, engine: &Engine) -> Result<(), Error> {
+pub fn verify_header_params(header: &Header, engine: &Engine) -> Result<(), Error> {
 	if header.number() >= From::from(BlockNumber::max_value()) {
 		return Err(From::from(BlockError::RidiculousNumber(OutOfBounds { max: Some(From::from(BlockNumber::max_value())), min: None, found: header.number() })))
 	}