Separate JNI implementation for ProofMap [ECR-3983] (#1299)

Separate JNI implementation for ProofMap into RawProofMap 
(no key hashing) and ProofMap (hashes keys).

Java still relies on the previous implementation, 
and will migrate to the new ones in ECR-3850

Author: skletsun

exonum-java-binding/core/rust/src/storage/mod.rs

@@ -22,6 +22,8 @@ mod map_index;
 mod pair_iter;
 mod proof_list_index;
 mod proof_map_index;
+mod proof_map_index_next;
+mod raw_proof_map_index;
 mod temporarydb;
 mod value_set_index;
 
@@ -35,5 +37,7 @@ pub use self::map_index::*;
 pub use self::pair_iter::PairIter;
 pub use self::proof_list_index::*;
 pub use self::proof_map_index::*;
+pub use self::proof_map_index_next::*;
+pub use self::raw_proof_map_index::*;
 pub use self::temporarydb::*;
 pub use self::value_set_index::*;

exonum-java-binding/core/rust/src/storage/proof_list_index.rs

@@ -12,24 +12,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use exonum_merkledb::{
-    access::FromAccess, proof_list_index::ProofListIndexIter, Fork, IndexAddress, ListProof,
-    ObjectHash, ProofListIndex, Snapshot,
+use exonum::merkledb::{
+    access::FromAccess, proof_list_index::ProofListIndexIter, Fork, IndexAddress, ObjectHash,
+    ProofListIndex, Snapshot,
 };
-use exonum_proto::ProtobufConvert;
 use jni::{
     objects::{JClass, JObject, JString},
     sys::{jboolean, jbyteArray, jint, jlong},
     JNIEnv,
 };
-use protobuf::Message;
 
 use std::{panic, ptr};
 
 use handle::{self, Handle};
 use storage::db::{Value, View, ViewRef};
 use utils;
-use JniResult;
 
 type Index<T> = ProofListIndex<T, Value>;
 
@@ -260,7 +257,7 @@ pub extern "system" fn Java_com_exonum_binding_core_storage_indices_ProofListInd
             IndexType::SnapshotIndex(ref list) => list.get_proof(index as u64),
             IndexType::ForkIndex(ref list) => list.get_proof(index as u64),
         };
-        proof_to_bytes(&env, proof)
+        utils::proto_to_java_bytes(&env, proof)
     });
     utils::unwrap_exc_or(&env, res, ptr::null_mut())
 }
@@ -280,7 +277,7 @@ pub extern "system" fn Java_com_exonum_binding_core_storage_indices_ProofListInd
             IndexType::SnapshotIndex(ref list) => list.get_range_proof(from as u64..to as u64),
             IndexType::ForkIndex(ref list) => list.get_range_proof(from as u64..to as u64),
         };
-        proof_to_bytes(&env, proof)
+        utils::proto_to_java_bytes(&env, proof)
     });
     utils::unwrap_exc_or(&env, res, ptr::null_mut())
 }
@@ -410,8 +407,3 @@ pub extern "system" fn Java_com_exonum_binding_core_storage_indices_ProofListInd
 ) {
     handle::drop_handle::<ProofListIndexIter<Value>>(&env, iter_handle);
 }
-
-// Serializes `ListProof` into protobuf format and converts to the Java bytes array.
-fn proof_to_bytes(env: &JNIEnv, proof: ListProof<Value>) -> JniResult<jbyteArray> {
-    env.byte_array_from_slice(&proof.to_pb().write_to_bytes().unwrap())
-}