A more comprehensive model for PoV-Blocks and Candidate receipts (#843)

* encode the candidate statement as only the hash

* refactor CandidateReceipt and CollationInfo

* introduce an abridged candidate receipt type

* erasure coding stores candidate receipt

* store omitted data instead and introduce AvailableData type

* refactor availability-store schema

* tweak schema and APIs a bit more

* get availability-store tests passing

* accept AbridgedCandidateReceipt in `set_heads`

* change statement type in primitives to be hash-only

* fix parachains runtime tests

* fix bad merge

* rewrite validation pipeline

* remove evaluation module

* use abridged candidate hash as canonical

* statement table uses abridged candidate receipts

* kill availability_store::Data struct

* port shared table to new validation pipelines

* extract full validation pipeline to helper

* remove old validation pipeline from collation module

* polkadot-validation compiles

* polkadot-validation tests compile

* make local collation available in validation service

* port legacy network code

* polkadot-network fully ported

* network: ensure fresh statement is propagated

* remove pov_block_hash from LocalValidationData

* remove candidate_hash field from AttestedCandidate and update runtime

* port runtimes to new ParachainHost definition

* port over polkadot-collator

* fix test compilation

* better fix

* remove unrelated validation work dispatch fix

* address grumbles

* fix equality check

polkadot/statement-table/src/lib.rs

@@ -19,18 +19,28 @@ pub mod generic;
 pub use generic::Table;
 
 use primitives::parachain::{
-	Id, CandidateReceipt, Statement as PrimitiveStatement, ValidatorSignature, ValidatorIndex,
+	Id, AbridgedCandidateReceipt, Statement as PrimitiveStatement, ValidatorSignature, ValidatorIndex,
 };
 use primitives::Hash;
 
 /// Statements about candidates on the network.
-pub type Statement = generic::Statement<CandidateReceipt, Hash>;
+pub type Statement = generic::Statement<AbridgedCandidateReceipt, Hash>;
 
 /// Signed statements about candidates.
-pub type SignedStatement = generic::SignedStatement<CandidateReceipt, Hash, ValidatorIndex, ValidatorSignature>;
+pub type SignedStatement = generic::SignedStatement<
+	AbridgedCandidateReceipt,
+	Hash,
+	ValidatorIndex,
+	ValidatorSignature,
+>;
 
 /// Kinds of misbehavior, along with proof.
-pub type Misbehavior = generic::Misbehavior<CandidateReceipt, Hash, ValidatorIndex, ValidatorSignature>;
+pub type Misbehavior = generic::Misbehavior<
+	AbridgedCandidateReceipt,
+	Hash,
+	ValidatorIndex,
+	ValidatorSignature,
+>;
 
 /// A summary of import of a statement.
 pub type Summary = generic::Summary<Hash, Id>;
@@ -50,13 +60,13 @@ impl<C: Context> generic::Context for C {
 	type Digest = Hash;
 	type GroupId = Id;
 	type Signature = ValidatorSignature;
-	type Candidate = CandidateReceipt;
+	type Candidate = AbridgedCandidateReceipt;
 
-	fn candidate_digest(candidate: &CandidateReceipt) -> Hash {
+	fn candidate_digest(candidate: &AbridgedCandidateReceipt) -> Hash {
 		candidate.hash()
 	}
 
-	fn candidate_group(candidate: &CandidateReceipt) -> Id {
+	fn candidate_group(candidate: &AbridgedCandidateReceipt) -> Id {
 		candidate.parachain_index.clone()
 	}
 
@@ -69,12 +79,12 @@ impl<C: Context> generic::Context for C {
 	}
 }
 
-impl From<Statement> for PrimitiveStatement {
-	fn from(s: Statement) -> PrimitiveStatement {
-		match s {
+impl<'a> From<&'a Statement> for PrimitiveStatement {
+	fn from(s: &'a Statement) -> PrimitiveStatement {
+		match *s {
 			generic::Statement::Valid(s) => PrimitiveStatement::Valid(s),
 			generic::Statement::Invalid(s) => PrimitiveStatement::Invalid(s),
-			generic::Statement::Candidate(s) => PrimitiveStatement::Candidate(s),
+			generic::Statement::Candidate(ref s) => PrimitiveStatement::Candidate(s.hash()),
 		}
 	}
 }