client: use std::string_view for call function

For most of cases encoding fuction such as `call`, `execute` and
`prepare` use predefined fixed literal. Those values are best to
be expressed as std::string_view literals.
std::string_view are really usefull and can be easily createad
from any sequense memory areas.
There are no changes are required from cliend side as
std::string_view can be implicilty coverted from std::string.

Author: pmelkozer

src/Client/Connection.hpp

@@ -37,6 +37,7 @@
 
 #include <sys/uio.h> //iovec
 #include <string>
+#include <string_view>
 #include <unordered_map> //futures
 
 /** rid == request id */
@@ -175,7 +176,7 @@ class Connection
 	size_t getFutureCount() const;
 
 	template <class T>
-	rid_t call(const std::string &func, const T &args);
+	rid_t call(std::string_view func, const T &args);
 	rid_t ping();
 
 	/**
@@ -185,7 +186,7 @@ class Connection
 	 * @retval request id
 	 */
 	template <class T>
-	rid_t execute(const std::string& statement, const T& parameters);
+	rid_t execute(std::string_view statement, const T& parameters);
 
 	/**
 	 * Execute the SQL statement contained in the 'statement' parameter.
@@ -203,7 +204,7 @@ class Connection
 	 * @param statement statement, which should conform to the rules for SQL grammar
 	 * @retval request id
 	 */
-	rid_t prepare(const std::string& statement);
+	rid_t prepare(std::string_view statement);
 
 	void setError(const std::string &msg, int errno_ = 0);
 	bool hasError() const;
@@ -606,7 +607,7 @@ decodeGreeting(Connection<BUFFER, NetProvider> &conn)
 template<class BUFFER, class NetProvider>
 template <class T>
 rid_t
-Connection<BUFFER, NetProvider>::execute(const std::string& statement, const T& parameters)
+Connection<BUFFER, NetProvider>::execute(std::string_view statement, const T& parameters)
 {
     impl->enc.encodeExecute(statement, parameters);
     impl->connector.readyToSend(*this);
@@ -625,7 +626,7 @@ Connection<BUFFER, NetProvider>::execute(unsigned int stmt_id, const T& paramete
 
 template<class BUFFER, class NetProvider>
 rid_t
-Connection<BUFFER, NetProvider>::prepare(const std::string& statement)
+Connection<BUFFER, NetProvider>::prepare(std::string_view statement)
 {
     impl->enc.encodePrepare(statement);
     impl->connector.readyToSend(*this);
@@ -635,7 +636,7 @@ Connection<BUFFER, NetProvider>::prepare(const std::string& statement)
 template<class BUFFER, class NetProvider>
 template <class T>
 rid_t
-Connection<BUFFER, NetProvider>::call(const std::string &func, const T &args)
+Connection<BUFFER, NetProvider>::call(std::string_view func, const T &args)
 {
 	impl->enc.encodeCall(func, args);
 	impl->connector.readyToSend(*this);

src/Client/RequestEncoder.hpp

@@ -32,6 +32,7 @@
 #include <any>
 #include <cstdint>
 #include <map>
+#include <string_view>
 
 #include "IprotoConstants.hpp"
 #include "ResponseReader.hpp"
@@ -85,12 +86,12 @@ class RequestEncoder {
 			    uint32_t limit = UINT32_MAX, uint32_t offset = 0,
 			    IteratorType iterator = EQ);
 	template <class T>
-	size_t encodeExecute(const std::string& statement, const T& parameters);
+	size_t encodeExecute(std::string_view statement, const T& parameters);
 	template <class T>
 	size_t encodeExecute(unsigned int stmt_id, const T& parameters);
-	size_t encodePrepare(const std::string& statement);
+	size_t encodePrepare(std::string_view statement);
 	template <class T>
-	size_t encodeCall(const std::string &func, const T &args);
+	size_t encodeCall(std::string_view func, const T &args);
 	size_t encodeAuth(std::string_view user, std::string_view passwd,
 			  const Greeting &greet);
 	void reencodeAuth(std::string_view user, std::string_view passwd,
@@ -256,7 +257,7 @@ RequestEncoder<BUFFER>::encodeSelect(const T &key,
 template<class BUFFER>
 template <class T>
 size_t
-RequestEncoder<BUFFER>::encodeExecute(const std::string& statement, const T& parameters)
+RequestEncoder<BUFFER>::encodeExecute(std::string_view statement, const T& parameters)
 {
 	iterator_t<BUFFER> request_start = m_Buf.end();
 	m_Buf.write('\xce');
@@ -293,7 +294,7 @@ RequestEncoder<BUFFER>::encodeExecute(unsigned int stmt_id, const T& parameters)
 
 template<class BUFFER>
 size_t
-RequestEncoder<BUFFER>::encodePrepare(const std::string& statement)
+RequestEncoder<BUFFER>::encodePrepare(std::string_view statement)
 {
 	iterator_t<BUFFER> request_start = m_Buf.end();
 	m_Buf.write('\xce');
@@ -310,7 +311,7 @@ RequestEncoder<BUFFER>::encodePrepare(const std::string& statement)
 template<class BUFFER>
 template <class T>
 size_t
-RequestEncoder<BUFFER>::encodeCall(const std::string &func, const T &args)
+RequestEncoder<BUFFER>::encodeCall(std::string_view func, const T &args)
 {
 	iterator_t<BUFFER> request_start = m_Buf.end();
 	m_Buf.write('\xce');