separated from blockchain and made reusable db reader and batch writer

ethcore/src/blockchain/blockchain.rs

@@ -30,7 +30,7 @@ use blockchain::bloom_indexer::BloomIndexer;
 use blockchain::tree_route::TreeRoute;
 use blockchain::update::ExtrasUpdate;
 use blockchain::{CacheSize, ImportRoute};
-use db::{Writable, Readable, Key};
+use db::{Writable, Readable, Key, DatabaseReader, BatchWriter, CacheUpdatePolicy};
 
 const BLOOM_INDEX_SIZE: usize = 16;
 const BLOOM_LEVELS: u8 = 3;
@@ -183,7 +183,7 @@ impl BlockProvider for BlockChain {
 	/// Returns true if the given block is known
 	/// (though not necessarily a part of the canon chain).
 	fn is_known(&self, hash: &H256) -> bool {
-		self.query_extras_exist(hash, &self.block_details)
+		DatabaseReader::new(&self.extras_db, &self.block_details).exists(hash)
 	}
 
 	// We do not store tracing information.
@@ -466,28 +466,25 @@ impl BlockChain {
 		batch.put(b"best", &update.info.hash).unwrap();
 
 		{
-			let mut write_details = self.block_details.write().unwrap();
-			for (hash, details) in update.block_details.into_iter() {
-				batch.write(&hash, &details);
-				self.note_used(CacheID::Extras(ExtrasIndex::BlockDetails, hash.clone()));
-				write_details.insert(hash, details);
+			for hash in update.block_details.keys().cloned() {
+				self.note_used(CacheID::Extras(ExtrasIndex::BlockDetails, hash));
 			}
+
+			let mut write_details = self.block_details.write().unwrap();
+			BatchWriter::new(&batch, &mut write_details)
+				.extend(update.block_details, CacheUpdatePolicy::Overwrite);
 		}
 
 		{
 			let mut write_receipts = self.block_receipts.write().unwrap();
-			for (hash, receipt) in &update.block_receipts {
-				batch.write(hash, receipt);
-				write_receipts.remove(hash);
-			}
+			BatchWriter::new(&batch, &mut write_receipts)
+				.extend(update.block_receipts, CacheUpdatePolicy::Remove);
 		}
 
 		{
 			let mut write_blocks_blooms = self.blocks_blooms.write().unwrap();
-			for (bloom_hash, blocks_bloom) in &update.blocks_blooms {
-				batch.write(bloom_hash, blocks_bloom);
-				write_blocks_blooms.remove(bloom_hash);
-			}
+			BatchWriter::new(&batch, &mut write_blocks_blooms)
+				.extend(update.blocks_blooms, CacheUpdatePolicy::Remove);
 		}
 
 		// These cached values must be updated last and togeterh
@@ -508,15 +505,11 @@ impl BlockChain {
 				}
 			}
 
-			for (number, hash) in &update.block_hashes {
-				batch.write(number, hash);
-				write_hashes.remove(number);
-			}
+			BatchWriter::new(&batch, &mut write_hashes)
+				.extend(update.block_hashes, CacheUpdatePolicy::Remove);
 
-			for (hash, tx_address) in &update.transactions_addresses {
-				batch.write(hash, tx_address);
-				write_txs.remove(hash);
-			}
+			BatchWriter::new(&batch, &mut write_txs)
+				.extend(update.transactions_addresses, CacheUpdatePolicy::Remove);
 
 			// update extras database
 			self.extras_db.write(batch).unwrap();
@@ -751,32 +744,8 @@ impl BlockChain {
 		T: ExtrasIndexable + Clone + Decodable,
 		K: Key<T> + Eq + Hash + Clone,
 		H256: From<K> {
-		{
-			let read = cache.read().unwrap();
-			if let Some(v) = read.get(hash) {
-				return Some(v.clone());
-			}
-		}
-
 		self.note_used(CacheID::Extras(T::index(), H256::from(hash.clone())));
-
-		self.extras_db.read(hash).map(|t: T| {
-			let mut write = cache.write().unwrap();
-			write.insert(hash.clone(), t.clone());
-			t
-		})
-	}
-
-	fn query_extras_exist<K, T>(&self, hash: &K, cache: &RwLock<HashMap<K, T>>) -> bool where
-		K: Key<T> + Eq + Hash + Clone {
-		{
-			let read = cache.read().unwrap();
-			if let Some(_) = read.get(hash) {
-				return true;
-			}
-		}
-
-		self.extras_db.exists::<T>(hash)
+		DatabaseReader::new(&self.extras_db, cache).read(hash)
 	}
 
 	/// Get current cache size.

ethcore/src/db/mod.rs

@@ -0,0 +1,23 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+pub mod db;
+mod reader;
+mod writer;
+
+pub use self::db::{Key, Writable, Readable};
+pub use self::reader::DatabaseReader;
+pub use self::writer::{BatchWriter, CacheUpdatePolicy};

ethcore/src/db/reader.rs

@@ -0,0 +1,65 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::hash::Hash;
+use std::sync::RwLock;
+use std::collections::HashMap;
+use util::Database;
+use util::rlp::Decodable;
+use super::{Readable, Key};
+
+pub struct DatabaseReader<'a, K, V> where K: 'a, V: 'a {
+	db: &'a Database,
+	cache: &'a RwLock<HashMap<K, V>>,
+}
+
+impl<'a, K, V> DatabaseReader<'a, K, V> {
+	pub fn new(db: &'a Database, cache: &'a RwLock<HashMap<K, V>>) -> Self {
+		DatabaseReader {
+			db: db,
+			cache: cache,
+		}
+	}
+
+	pub fn read(&self, key: &K) -> Option<V> where
+	K: Eq + Hash + Clone + Key<V>,
+	V: Clone + Decodable {
+		{
+			let read = self.cache.read().unwrap();
+			if let Some(v) = read.get(key) {
+				return Some(v.clone());
+			}
+		}
+
+		self.db.read(key).map(|value: V|{
+			let mut write = self.cache.write().unwrap();
+			write.insert(key.clone(), value.clone());
+			value
+		})
+	}
+
+	pub fn exists(&self, key: &K) -> bool where
+	K: Eq + Hash + Key<V> {
+		{
+			let read = self.cache.read().unwrap();
+			if read.get(key).is_some() {
+				return true;
+			}
+		}
+
+		self.db.exists::<V>(key)
+	}
+}

ethcore/src/db/writer.rs

@@ -0,0 +1,60 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::collections::HashMap;
+use std::hash::Hash;
+use util::DBTransaction;
+use util::rlp::Encodable;
+use super::{Key, Writable};
+
+#[derive(Clone, Copy)]
+pub enum CacheUpdatePolicy {
+	Overwrite,
+	Remove,
+}
+
+pub struct BatchWriter<'a, K, V> where K: 'a, V: 'a {
+	batch: &'a DBTransaction,
+	cache: &'a mut HashMap<K, V>,
+}
+
+impl<'a, K, V> BatchWriter<'a, K, V> {
+	pub fn new(batch: &'a DBTransaction, cache: &'a mut HashMap<K, V>) -> Self {
+		BatchWriter {
+			batch: batch,
+			cache: cache,
+		}
+	}
+
+	pub fn extend(&mut self, map: HashMap<K, V>, policy: CacheUpdatePolicy) where
+	K: Key<V> + Hash + Eq,
+	V: Encodable {
+		match policy {
+			CacheUpdatePolicy::Overwrite => {
+				for (key, value) in map.into_iter() {
+					self.batch.write(&key, &value);
+					self.cache.insert(key, value);
+				}
+			},
+			CacheUpdatePolicy::Remove => {
+				for (key, value) in &map {
+					self.batch.write(key, value);
+					self.cache.remove(key);
+				}
+			},
+		}
+	}
+}