Check for pruned block state

substrate/client/db/src/lib.rs

@@ -300,12 +300,12 @@ impl<Block: BlockT> Backend<Block> {
 	}
 
 	#[cfg(test)]
-	fn new_test() -> Self {
+	fn new_test(keep_blocks: u32) -> Self {
 		use utils::NUM_COLUMNS;
 
 		let db = Arc::new(::kvdb_memorydb::create(NUM_COLUMNS));
 
-		Backend::from_kvdb(db as Arc<_>, PruningMode::keep_blocks(0), 0).expect("failed to create test-db")
+		Backend::from_kvdb(db as Arc<_>, PruningMode::keep_blocks(keep_blocks), 0).expect("failed to create test-db")
 	}
 
 	fn from_kvdb(db: Arc<KeyValueDB>, pruning: PruningMode, finalization_window: u64) -> Result<Self, client::error::Error> {
@@ -454,10 +454,14 @@ impl<Block> client::backend::Backend<Block, KeccakHasher, RlpCodec> for Backend<
 			_ => {}
 		}
 
-		self.blockchain.header(block).and_then(|maybe_hdr| maybe_hdr.map(|hdr| {
-			let root: H256 = H256::from_slice(hdr.state_root().as_ref());
-			DbState::with_storage(self.storage.clone(), root)
-		}).ok_or_else(|| client::error::ErrorKind::UnknownBlock(format!("{:?}", block)).into()))
+		match self.blockchain.header(block) {
+			Ok(Some(ref hdr)) if !self.storage.state_db.is_pruned(hdr.number().as_()) => {
+				let root = H256::from_slice(hdr.state_root().as_ref());
+				Ok(DbState::with_storage(self.storage.clone(), root))
+			},
+			Err(e) => Err(e),
+			_ => Err(client::error::ErrorKind::UnknownBlock(format!("{:?}", block)).into()),
+		}
 	}
 }
 
@@ -477,7 +481,7 @@ mod tests {
 
 	#[test]
 	fn block_hash_inserted_correctly() {
-		let db = Backend::<Block>::new_test();
+		let db = Backend::<Block>::new_test(1);
 		for i in 0..10 {
 			assert!(db.blockchain().hash(i).unwrap().is_none());
 
@@ -516,7 +520,7 @@ mod tests {
 
 	#[test]
 	fn set_state_data() {
-		let db = Backend::<Block>::new_test();
+		let db = Backend::<Block>::new_test(2);
 		{
 			let mut op = db.begin_operation(BlockId::Hash(Default::default())).unwrap();
 			let mut header = Header {
@@ -595,7 +599,7 @@ mod tests {
 	#[test]
 	fn delete_only_when_negative_rc() {
 		let key;
-		let backend = Backend::<Block>::new_test();
+		let backend = Backend::<Block>::new_test(0);
 
 		let hash = {
 			let mut op = backend.begin_operation(BlockId::Hash(Default::default())).unwrap();

substrate/state-db/src/lib.rs

@@ -226,6 +226,10 @@ impl<BlockHash: Hash, Key: Hash> StateDbSync<BlockHash, Key> {
 		return self.unfinalized.last_finalized_block_number()
 	}
 
+	pub fn is_pruned(&self, number: u64) -> bool {
+		self.pruning.as_ref().map_or(false, |pruning| number < pruning.pending())
+	}
+
 	fn prune(&mut self, commit: &mut CommitSet<Key>) {
 		if let (&mut Some(ref mut pruning), &PruningMode::Constrained(ref constraints)) = (&mut self.pruning, &self.mode) {
 			loop {
@@ -241,7 +245,6 @@ impl<BlockHash: Hash, Key: Hash> StateDbSync<BlockHash, Key> {
 				if pruning.next_hash().map_or(false, |h| pinned.contains(&h)) {
 					break;
 				}
-
 				pruning.prune_one(commit);
 			}
 		}
@@ -328,6 +331,10 @@ impl<BlockHash: Hash, Key: Hash> StateDb<BlockHash, Key> {
 		return self.db.read().best_finalized()
 	}
 
+	/// Check if block is pruned away.
+	pub fn is_pruned(&self, number: u64) -> bool {
+		return self.db.read().is_pruned(number)
+	}
 }
 
 #[cfg(test)]
@@ -375,19 +382,24 @@ mod tests {
 
 	#[test]
 	fn prune_window_1() {
-		let (db, _) = make_test_db(PruningMode::Constrained(Constraints {
+		let (db, sdb) = make_test_db(PruningMode::Constrained(Constraints {
 			max_blocks: Some(1),
 			max_mem: None,
 		}));
+		assert!(sdb.is_pruned(0));
+		assert!(sdb.is_pruned(1));
+		assert!(!sdb.is_pruned(2));
 		assert!(db.data_eq(&make_db(&[21, 3, 922, 93, 94])));
 	}
 
 	#[test]
 	fn prune_window_2() {
-		let (db, _) = make_test_db(PruningMode::Constrained(Constraints {
+		let (db, sdb) = make_test_db(PruningMode::Constrained(Constraints {
 			max_blocks: Some(2),
 			max_mem: None,
 		}));
+		assert!(sdb.is_pruned(0));
+		assert!(!sdb.is_pruned(1));
 		assert!(db.data_eq(&make_db(&[1, 21, 3, 921, 922, 93, 94])));
 	}
 }

substrate/state-db/src/pruning.rs

@@ -60,7 +60,7 @@ impl<BlockHash: Hash, Key: Hash> RefWindow<BlockHash, Key> {
 			.map_err(|e| Error::Db(e))?;
 		let pending_number: u64 = match last_pruned {
 			Some(buffer) => u64::decode(&mut buffer.as_slice()).ok_or(Error::Decoding)? + 1,
-			None => 1,
+			None => 0,
 		};
 		let mut block = pending_number;
 		let mut pruning = RefWindow {
@@ -69,7 +69,7 @@ impl<BlockHash: Hash, Key: Hash> RefWindow<BlockHash, Key> {
 			pending_number: pending_number,
 		};
 		// read the journal
-		trace!(target: "state-db", "Reading pruning journal. Last pruned #{}", pending_number - 1);
+		trace!(target: "state-db", "Reading pruning journal. Pending #{}", pending_number);
 		loop {
 			let journal_key = to_journal_key(block);
 			match db.get_meta(&journal_key).map_err(|e| Error::Db(e))? {
@@ -119,6 +119,10 @@ impl<BlockHash: Hash, Key: Hash> RefWindow<BlockHash, Key> {
 		0
 	}
 
+	pub fn pending(&self) -> u64 {
+		self.pending_number
+	}
+
 	/// Prune next block. Expects at least one block in the window. Adds changes to `commit`.
 	pub fn prune_one(&mut self, commit: &mut CommitSet<Key>) {
 		let pruned = self.death_rows.pop_front().expect("prune_one is only called with a non-empty window");
@@ -168,7 +172,7 @@ mod tests {
 	fn created_from_empty_db() {
 		let db = make_db(&[]);
 		let pruning: RefWindow<H256, H256> = RefWindow::new(&db).unwrap();
-		assert_eq!(pruning.pending_number, 1);
+		assert_eq!(pruning.pending_number, 0);
 		assert!(pruning.death_rows.is_empty());
 		assert!(pruning.death_index.is_empty());
 	}
@@ -202,7 +206,7 @@ mod tests {
 		assert!(db.data_eq(&make_db(&[2, 4, 5])));
 		assert!(pruning.death_rows.is_empty());
 		assert!(pruning.death_index.is_empty());
-		assert_eq!(pruning.pending_number, 2);
+		assert_eq!(pruning.pending_number, 1);
 	}
 
 	#[test]
@@ -227,7 +231,7 @@ mod tests {
 		pruning.prune_one(&mut commit);
 		db.commit(&commit);
 		assert!(db.data_eq(&make_db(&[3, 4, 5])));
-		assert_eq!(pruning.pending_number, 3);
+		assert_eq!(pruning.pending_number, 2);
 	}
 
 	#[test]
@@ -258,6 +262,6 @@ mod tests {
 		pruning.prune_one(&mut commit);
 		db.commit(&commit);
 		assert!(db.data_eq(&make_db(&[1, 3])));
-		assert_eq!(pruning.pending_number, 4);
+		assert_eq!(pruning.pending_number, 3);
 	}
 }