[FAB-4974] Ledger proto messages enhancement for sidedb

This CR enhances the proto message for supporting the
hashed read-write set and private read-write set for the
private data. To summarize - under a namespace (chaincodeid),
there could be one or more sub-spaces (referred to as collections)
for managing private state. The hashed read-write set is intented
be part of the block and the private read-write set is intented to be
transferred to the need-to-have peers only.

Change-Id: I2f5127f93c945ab6559ed625f677d467e67bbcda
Signed-off-by: manish <manish.sethi@gmail.com>

Author: manish-sethi

protos/ledger/rwset/kvrwset/kv_rwset.pb.go

@@ -22,12 +22,19 @@ option java_package = "org.hyperledger.fabric.protos.ledger.rwset.kvrwset";
 package kvrwset;
 
 // KVRWSet encapsulates the read-write set for a chaincode that operates upon a KV or Document data model
+// This structure is used for both the public data and the private data
 message KVRWSet {
     repeated KVRead reads = 1;
     repeated RangeQueryInfo range_queries_info = 2;
     repeated KVWrite writes = 3;
 }
 
+// HashedRWSet encapsulates hashed representation of a private read-write set for KV or Document data model
+message HashedRWSet {
+    repeated KVReadHash hashed_reads = 1;
+    repeated KVWriteHash hashed_writes = 2;
+}
+
 // KVRead captures a read operation performed during transaction simulation
 // A 'nil' version indicates a non-existing key read by the transaction
 message KVRead {
@@ -42,6 +49,21 @@ message KVWrite {
     bytes value = 3;
 }
 
+// KVReadHash is similar to the KVRead in spirit. However, it captures the hash of the key instead of the key itself
+// version is kept as is for now. However, if the version also needs to be privacy-protected, it would need to be the
+// hash of the version and hence of 'bytes' type
+message KVReadHash {
+    bytes key_hash = 1;
+    Version version = 2;
+}
+
+// KVWriteHash is similar to the KVWrite in spiritcaptures a write (update/delete) operation performed during transaction simulation
+message KVWriteHash {
+    bytes key_hash = 1;
+    bool is_delete = 2;
+    bytes value_hash = 3;
+}
+
 // Version encapsulates the version of a Key
 // A version of a committed key is maintained as the height of the transaction that committed the key.
 // The height is represenetd as a tuple <blockNum, txNum> where the txNum is the height of the transaction

protos/ledger/rwset/kvrwset/kv_rwset.proto

@@ -0,0 +1,2 @@
+# Define binary file attributes.
+kvrwsetV1ProtoBytes binary