Storage tracing (#3614)

* Storage tracing

* Whitepsaces

Co-Authored-By: Sergei Pepyakin <sergei@parity.io>

* Apply suggestions from code review

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Update Cargo.lock

substrate/core/client/db/src/lib.rs

@@ -110,6 +110,12 @@ impl<B: BlockT> Drop for RefTrackingState<B> {
 	}
 }
 
+impl<Block: BlockT> std::fmt::Debug for RefTrackingState<Block> {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "Block {:?}", self.parent_hash)
+	}
+}
+
 impl<B: BlockT> StateBackend<Blake2Hasher> for RefTrackingState<B> {
 	type Error =  <DbState as StateBackend<Blake2Hasher>>::Error;
 	type Transaction = <DbState as StateBackend<Blake2Hasher>>::Transaction;

substrate/core/client/db/src/storage_cache.rs

@@ -285,6 +285,12 @@ pub struct CachingState<H: Hasher, S: StateBackend<H>, B: BlockT> {
 	pub cache: CacheChanges<H, B>
 }
 
+impl<H: Hasher, S: StateBackend<H>, B: BlockT> std::fmt::Debug for CachingState<H, S, B> {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "Block {:?}", self.cache.parent_hash)
+	}
+}
+
 impl<H: Hasher, B: BlockT> CacheChanges<H, B> {
 	/// Propagate local cache into the shared cache and synchronize
 	/// the shared cache with the best block state.

substrate/core/client/src/light/backend.rs

@@ -325,6 +325,15 @@ where
 	}
 }
 
+impl<H: Hasher> std::fmt::Debug for GenesisOrUnavailableState<H> {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		match *self {
+			GenesisOrUnavailableState::Genesis(ref state) => state.fmt(f),
+			GenesisOrUnavailableState::Unavailable => write!(f, "Unavailable"),
+		}
+	}
+}
+
 impl<H: Hasher> StateBackend<H> for GenesisOrUnavailableState<H>
 	where
 		H::Out: Ord,