Check queue to determine major importing (#2763)

* simplify major sync detection

* fix typos

* fix merge

* more realistic EthTester

* add new synced state

* remove Blocks synced state

* move is_major_importing to rpc crate and check queue

* add tests

rpc/src/v1/helpers/block_import.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/>.
+
+//! Block import analysis functions.
+
+use ethcore::client::BlockQueueInfo;
+use ethsync::SyncState;
+
+/// Check if client is during major sync or during block import.
+pub fn is_major_importing(sync_state: Option<SyncState>, queue_info: BlockQueueInfo) -> bool {
+	let is_syncing_state = sync_state.map_or(false, |s|
+		s != SyncState::Idle && s != SyncState::NewBlocks
+	);
+	let is_verifying = queue_info.unverified_queue_size + queue_info.verified_queue_size > 3;
+	is_verifying || is_syncing_state
+}
+
+#[cfg(test)]
+mod tests {
+	use ethcore::client::BlockQueueInfo;
+	use ethsync::SyncState;
+	use super::is_major_importing;
+
+
+	fn queue_info(unverified: usize, verified: usize) -> BlockQueueInfo {
+		BlockQueueInfo {
+			unverified_queue_size: unverified,
+			verified_queue_size: verified,
+			verifying_queue_size: 0,
+			max_queue_size: 1000,
+			max_mem_use: 1000,
+			mem_used: 500
+		}
+	}
+
+	#[test]
+	fn is_still_verifying() {
+		assert!(!is_major_importing(None, queue_info(2, 1)));
+		assert!(is_major_importing(None, queue_info(2, 2)));
+	}
+
+	#[test]
+	fn is_synced_state() {
+		assert!(is_major_importing(Some(SyncState::Blocks), queue_info(0, 0)));
+		assert!(!is_major_importing(Some(SyncState::Idle), queue_info(0, 0)));
+	}
+}