Extract well known keys into a single place (#764)

* Extract well known keys into a single place

* Fixes.

substrate/core/state-machine/src/changes_trie/build.rs

@@ -148,6 +148,7 @@ fn prepare_digest_input<'a, S, H, C>(
 mod test {
 	use codec::Encode;
 	use primitives::{Blake2Hasher, RlpCodec};
+	use primitives::storage::well_known_keys::EXTRINSIC_INDEX;
 	use backend::InMemory;
 	use changes_trie::storage::InMemoryStorage;
 	use overlayed_changes::OverlayedValue;
@@ -208,7 +209,7 @@ mod test {
 				}),
 			].into_iter().collect(),
 			committed: vec![
-				(b":extrinsic_index".to_vec(), OverlayedValue {
+				(EXTRINSIC_INDEX.to_vec(), OverlayedValue {
 					value: Some(3u32.encode()),
 					extrinsics: None,
 				}),

substrate/core/state-machine/src/ext.rs

@@ -229,6 +229,7 @@ where
 mod tests {
 	use codec::Encode;
 	use primitives::{Blake2Hasher, RlpCodec};
+	use primitives::storage::well_known_keys::EXTRINSIC_INDEX;
 	use backend::InMemory;
 	use changes_trie::{Configuration as ChangesTrieConfiguration,
 		InMemoryStorage as InMemoryChangesTrieStorage};
@@ -242,7 +243,7 @@ mod tests {
 	fn prepare_overlay_with_changes() -> OverlayedChanges {
 		OverlayedChanges {
 			prospective: vec![
-				(b":extrinsic_index".to_vec(), OverlayedValue {
+				(EXTRINSIC_INDEX.to_vec(), OverlayedValue {
 					value: Some(3u32.encode()),
 					extrinsics: Some(vec![1].into_iter().collect())
 				}),

substrate/core/state-machine/src/lib.rs

@@ -44,6 +44,7 @@ use patricia_trie::NodeCodec;
 use rlp::Encodable;
 use heapsize::HeapSizeOf;
 use codec::Decode;
+use primitives::storage::well_known_keys;
 
 pub mod backend;
 mod changes_trie;
@@ -260,11 +261,11 @@ where
 	let strategy: ExecutionStrategy = (&manager).into();
 
 	// make a copy.
-	let code = try_read_overlay_value(overlay, backend, b":code")?
+	let code = try_read_overlay_value(overlay, backend, well_known_keys::CODE)?
 		.ok_or_else(|| Box::new(ExecutionError::CodeEntryDoesNotExist) as Box<Error>)?
 		.to_vec();
 
-	let heap_pages = try_read_overlay_value(overlay, backend, b":heappages")?
+	let heap_pages = try_read_overlay_value(overlay, backend, well_known_keys::HEAP_PAGES)?
 		.and_then(|v| u64::decode(&mut &v[..])).unwrap_or(8) as usize;
 
 	// read changes trie configuration. The reason why we're doing it here instead of the
@@ -272,7 +273,11 @@ where
 	// proof-of-execution on light clients. And the proof is recorded by the backend which
 	// is created after OverlayedChanges
 
-	let changes_trie_config = try_read_overlay_value(overlay, backend, b":changes_trie")?;
+	let changes_trie_config = try_read_overlay_value(
+		overlay,
+		backend,
+		well_known_keys::CHANGES_TRIE_CONFIG
+	)?;
 	set_changes_trie_config(overlay, changes_trie_config)?;
 
 	let result = {

substrate/core/state-machine/src/overlayed_changes.rs

@@ -19,6 +19,7 @@
 use std::collections::{HashMap, HashSet};
 use codec::Decode;
 use changes_trie::{NO_EXTRINSIC_INDEX, Configuration as ChangesTrieConfig};
+use primitives::storage::well_known_keys::EXTRINSIC_INDEX;
 
 /// The overlayed changes to state to be queried on top of the backend.
 ///
@@ -168,7 +169,7 @@ impl OverlayedChanges {
 	#[cfg(test)]
 	pub(crate) fn set_extrinsic_index(&mut self, extrinsic_index: u32) {
 		use codec::Encode;
-		self.prospective.insert(b":extrinsic_index".to_vec(), OverlayedValue {
+		self.prospective.insert(EXTRINSIC_INDEX.to_vec(), OverlayedValue {
 			value: Some(extrinsic_index.encode()),
 			extrinsics: None,
 		});
@@ -183,7 +184,7 @@ impl OverlayedChanges {
 	fn extrinsic_index(&self) -> Option<u32> {
 		match self.changes_trie_config.is_some() {
 			true => Some(
-				self.storage(b":extrinsic_index")
+				self.storage(EXTRINSIC_INDEX)
 					.and_then(|idx| idx.and_then(|idx| Decode::decode(&mut &*idx)))
 					.unwrap_or(NO_EXTRINSIC_INDEX)),
 			false => None,
@@ -201,6 +202,7 @@ impl From<Option<Vec<u8>>> for OverlayedValue {
 #[cfg(test)]
 mod tests {
 	use primitives::{Blake2Hasher, RlpCodec, H256};
+	use primitives::storage::well_known_keys::EXTRINSIC_INDEX;
 	use backend::InMemory;
 	use changes_trie::InMemoryStorage as InMemoryChangesTrieStorage;
 	use ext::Ext;
@@ -209,7 +211,7 @@ mod tests {
 
 	fn strip_extrinsic_index(map: &HashMap<Vec<u8>, OverlayedValue>) -> HashMap<Vec<u8>, OverlayedValue> {
 		let mut clone = map.clone();
-		clone.remove(&b":extrinsic_index".to_vec());
+		clone.remove(&EXTRINSIC_INDEX.to_vec());
 		clone
 	}
 

substrate/core/state-machine/src/testing.rs

@@ -25,6 +25,7 @@ use rlp::Encodable;
 use triehash::trie_root;
 use backend::InMemory;
 use changes_trie::{compute_changes_trie_root, InMemoryStorage as ChangesTrieInMemoryStorage};
+use primitives::storage::well_known_keys::CHANGES_TRIE_CONFIG;
 use super::{Externalities, OverlayedChanges};
 
 /// Simple HashMap-based Externalities impl.
@@ -41,7 +42,7 @@ impl<H: Hasher, C: NodeCodec<H>> TestExternalities<H, C> where H::Out: HeapSizeO
 		let mut overlay = OverlayedChanges::default();
 		super::set_changes_trie_config(
 			&mut overlay,
-			inner.get(&b":changes_trie".to_vec()).cloned())
+			inner.get(&CHANGES_TRIE_CONFIG.to_vec()).cloned())
 			.expect("changes trie configuration is correct in test env; qed");
 
 		TestExternalities {