[#68] policy: Add Version() method

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

policy/config.yml

@@ -4,3 +4,4 @@ safemethods:
   - "listChains"
   - "getChain"
   - "listChainsByPrefix"
+  - "version"

policy/policy_contract.go

@@ -58,6 +58,11 @@ func checkAuthorization(ctx storage.Context) {
 	panic(ErrNotAuthorized)
 }
 
+// Version returns the version of the contract.
+func Version() int {
+	return common.Version
+}
+
 func SetAdmin(addr interop.Hash160) {
 	common.CheckAlphabetWitness()
 

rpcclient/policy/client.go

@@ -72,6 +72,11 @@ func (c *ContractReader) ListChainsByPrefix(entity *big.Int, entityName string,
 	return unwrap.Array(c.invoker.Call(c.hash, "listChainsByPrefix", entity, entityName, prefix))
 }
 
+// Version invokes `version` method of contract.
+func (c *ContractReader) Version() (*big.Int, error) {
+	return unwrap.BigInt(c.invoker.Call(c.hash, "version"))
+}
+
 // AddChain creates a transaction invoking `addChain` method of the contract.
 // This transaction is signed and immediately sent to the network.
 // The values returned are its hash, ValidUntilBlock value and error if any.