Add code to submit scripts to Redis.

This is untested, but I can't test it until I implement other
things first. I also need to do some refactoring, so I need to
commit and make a checkpoint now.
Consider this code as good as if didn't exist.

src/backends/redis/CMakeLists.txt

@@ -1,6 +1,7 @@
 project(${bare_name}-backend-redis CXX)
 
 find_package(hiredis 0.11.0 REQUIRED)
+find_package(CryptoPP 5.6)
 
 add_library(${PROJECT_NAME} SHARED
 	backend_redis.cpp
@@ -15,6 +16,9 @@ target_include_directories(${PROJECT_NAME} SYSTEM
 	PRIVATE ${HIREDIS_INCLUDE_DIRS}
 	PRIVATE ${CMAKE_SOURCE_DIR}/lib/better-enums
 )
+target_include_directories(${PROJECT_NAME}
+	PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
+)
 
 target_link_libraries(${PROJECT_NAME}
 	PRIVATE ${bare_name}-inc
@@ -22,6 +26,19 @@ target_link_libraries(${PROJECT_NAME}
 	PRIVATE ${HIREDIS_LIBRARIES}
 )
 
+if (CryptoPP_FOUND)
+	target_link_libraries(${PROJECT_NAME} PRIVATE ${CryptoPP_LIBRARIES})
+	target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE ${CryptoPP_INCLUDE_DIRS})
+	set (has_cryptopp_lib ON)
+else()
+	set (has_cryptopp_lib OFF)
+endif()
+
+configure_file(
+	redisConfig.h.in
+	${CMAKE_CURRENT_BINARY_DIR}/redisConfig.h
+)
+
 install(TARGETS ${PROJECT_NAME}
 	LIBRARY DESTINATION lib
 	RUNTIME DESTINATION bin

src/backends/redis/batch.cpp

@@ -65,6 +65,7 @@ namespace redis {
 			};
 		}
 
+		extern "C"
 		void hiredis_run_callback (redisAsyncContext*, void* parReply, void* parPrivData) {
 			assert(parPrivData);
 			auto* data = static_cast<HiredisCallbackData*>(parPrivData);

src/backends/redis/command.cpp

@@ -16,6 +16,7 @@
  */
 
 #include "command.hpp"
+#include "helpers/lexical_cast.hpp"
 #include <hiredis/hiredis.h>
 #include <hiredis/async.h>
 #include <ciso646>
@@ -23,9 +24,23 @@
 #include <sstream>
 #include <algorithm>
 #include <stdexcept>
+#if defined(WITH_CRYPTOPP)
+#	include <crypto++/sha.h>
+#endif
 
 namespace redis {
 	namespace {
+#if defined(WITH_CRYPTOPP)
+		struct LuaScriptHash {
+			union {
+				struct {
+					uint64_t part_a, part_b;
+					uint32_t part_c;
+				};
+				uint8_t raw_bytes[20];
+			};
+		};
+#endif
 	} //unnamed namespace
 
 	Command::Command (std::string&& parAddress, uint16_t parPort) :
@@ -87,4 +102,57 @@ namespace redis {
 		assert(is_connected());
 		return Batch(m_conn.get());
 	}
+
+#if defined(WITH_CRYPTOPP)
+	boost::string_ref Command::add_lua_script_ifn (const std::string& parScript) {
+		if (parScript.empty())
+			return boost::string_ref();
+
+		using dinhelp::lexical_cast;
+
+		static_assert(20 == CryptoPP::SHA1::DIGESTSIZE, "Unexpected SHA1 digest size");
+		static_assert(sizeof(LuaScriptHash) >= CryptoPP::SHA1::DIGESTSIZE, "Wrong SHA1 struct size");
+		static_assert(Sha1Array().size() == CryptoPP::SHA1::DIGESTSIZE, "Wrong array size");
+
+		LuaScriptHash digest;
+		CryptoPP::SHA1().CalculateDigest(digest.raw_bytes, reinterpret_cast<const uint8_t*>(parScript.data()), parScript.size());
+		//TODO: change when lexical_cast will support arrays
+		const std::string sha1_str = lexical_cast<std::string>(digest.part_a) + lexical_cast<std::string>(digest.part_b) + lexical_cast<std::string>(digest.part_c);
+		Sha1Array sha1_array;
+		std::copy(sha1_str.begin(), sha1_str.end(), sha1_array.begin());
+
+		auto it_found = m_known_hashes.find(sha1_array);
+		const bool was_present = (m_known_hashes.end() != it_found);
+		if (was_present) {
+			return boost::string_ref(it_found->data(), it_found->size());
+		}
+
+		auto reply = this->run("SCRIPT", "LOAD", parScript);
+		assert(not was_present);
+
+		assert(get_string(reply) == sha1_str);
+		const auto it_inserted = m_known_hashes.insert(it_found, sha1_array);
+		(void)reply;
+
+		return boost::string_ref(it_inserted->data(), it_inserted->size());
+	}
+#else
+	boost::string_ref Command::add_lua_script_ifn (const std::string& parScript) {
+		auto it_found = m_known_hashes.find(parScript);
+		const bool was_present = (m_known_hashes.end() != it_found);
+		if (was_present) {
+			return boost::string_ref(it_found->second.data(), it_found->second.size());
+		}
+
+		auto reply = this->run("SCRIPT", "LOAD", parScript);
+		assert(not was_present);
+
+		const auto sha1_str = get_string(reply);
+		Sha1Array sha1_array;
+		std::copy(sha1_str.begin(), sha1_str.end(), sha1_array.begin());
+		auto it_inserted = m_known_hashes.insert(it_found, std::make_pair(parScript, sha1_array));
+
+		return boost::string_ref(it_inserted->second.data(), it_inserted->second.size());
+	}
+#endif
 } //namespace redis

src/backends/redis/command.hpp

@@ -21,6 +21,7 @@
 #include "scan_iterator.hpp"
 #include "reply.hpp"
 #include "batch.hpp"
+#include "redisConfig.h"
 #include <array>
 #include <memory>
 #include <string>
@@ -32,6 +33,12 @@
 #include <boost/range/iterator_range_core.hpp>
 #include <boost/utility/string_ref.hpp>
 #include <stdexcept>
+#if defined(WITH_CRYPTOPP)
+#	include <set>
+#else
+#	include <map>
+#endif
+#include <boost/utility/string_ref.hpp>
 
 struct redisAsyncContext;
 
@@ -66,10 +73,20 @@ namespace redis {
 		sscan_range sscan ( boost::string_ref parKey );
 		zscan_range zscan ( boost::string_ref parKey );
 
+		void submit_lua_script ( const std::string& parScript );
+
 	private:
 		using RedisConnection = std::unique_ptr<redisAsyncContext, void(*)(redisAsyncContext*)>;
+		using Sha1Array = std::array<char, 20>;
+
+		boost::string_ref add_lua_script_ifn ( const std::string& parScript );
 
 		RedisConnection m_conn;
+#if defined(WITH_CRYPTOPP)
+		std::set<Sha1Array> m_known_hashes;
+#else
+		std::map<std::string, Sha1Array> m_known_scripts;
+#endif
 		std::string m_address;
 		uint16_t m_port;
 	};

src/backends/redis/redisConfig.h.in

@@ -0,0 +1,27 @@
+/* Copyright 2015, 2016, Michele Santullo
+ * This file is part of "dindexer".
+ *
+ * "dindexer" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "dindexer" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "dindexer".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef idB3E2F339E3B64378B66342550C4D2089
+#define idB3E2F339E3B64378B66342550C4D2089
+
+#include "helpers/cmake_on_off.h"
+
+#if CMAKE_@has_cryptopp_lib@
+#	define WITH_CRYPTOPP
+#endif
+
+#endif