update wallet restore, generate new merkle proof for coinbase outputs (#1008)

chain/src/chain.rs

@@ -30,7 +30,7 @@ use pipe;
 use store;
 use txhashset;
 use types::*;
-use util::secp::pedersen::RangeProof;
+use util::secp::pedersen::{Commitment, RangeProof};
 use util::LOGGER;
 
 /// Orphan pool size is limited by MAX_ORPHAN_SIZE
@@ -507,6 +507,13 @@ impl Chain {
 		Ok(merkle_proof)
 	}
 
+	/// Return a merkle proof valid for the current output pmmr state at the
+	/// given pos
+	pub fn get_merkle_proof_for_pos(&self, commit: Commitment) -> Result<MerkleProof, String> {
+		let mut txhashset = self.txhashset.write().unwrap();
+		txhashset.merkle_proof(commit)
+	}
+
 	/// Returns current txhashset roots
 	pub fn get_txhashset_roots(&self) -> (Hash, Hash, Hash) {
 		let mut txhashset = self.txhashset.write().unwrap();

chain/src/txhashset.rs

@@ -205,6 +205,14 @@ impl TxHashSet {
 		(output_pmmr.root(), rproof_pmmr.root(), kernel_pmmr.root())
 	}
 
+	/// build a new merkle proof for the given position
+	pub fn merkle_proof(&mut self, commit: Commitment) -> Result<MerkleProof, String> {
+		let pos = self.commit_index.get_output_pos(&commit).unwrap();
+		let output_pmmr: PMMR<OutputIdentifier, _> =
+			PMMR::at(&mut self.output_pmmr_h.backend, self.output_pmmr_h.last_pos);
+		output_pmmr.merkle_proof(pos)
+	}
+
 	/// Compact the MMR data files and flush the rm logs
 	pub fn compact(&mut self) -> Result<(), Error> {
 		let commit_index = self.commit_index.clone();