added sqlite connection class (progress)

src/CMakeLists.txt

@@ -9,7 +9,8 @@ set(SQL_SOURCES
   sql/record.cpp
   sql/connection_info.cpp
   sql/connection_impl.cpp
-  sql/session.cpp)
+  sql/session.cpp
+  sql/backend_provider.cpp)
 
 set(SQL_HEADER
   ../include/matador/sql/dialect.hpp
@@ -27,19 +28,22 @@ set(SQL_HEADER
   ../include/matador/sql/connection_impl.hpp
   ../include/matador/sql/connection_info.hpp
   ../include/matador/sql/connection_pool.hpp
-  ../include/matador/sql/session.hpp)
+  ../include/matador/sql/session.hpp
+  ../include/matador/sql/backend_provider.hpp)
 
 set(UTILS_HEADER
   ../include/matador/utils/field_attributes.hpp
   ../include/matador/utils/string.hpp
   ../include/matador/utils/constraints.hpp
-  ../include/matador/utils/library.hpp)
+  ../include/matador/utils/library.hpp
+  ../include/matador/utils/os.hpp)
 
 set(UTILS_SOURCES
   utils/field_attributes.cpp
   utils/string.cpp
   sql/condition.cpp
-  utils/library.cpp)
+  utils/library.cpp
+  utils/os.cpp)
 
 add_library(matador STATIC ${SQL_SOURCES} ${SQL_HEADER} ${UTILS_SOURCES} ${UTILS_HEADER})
 target_include_directories(matador PUBLIC ${PROJECT_SOURCE_DIR}/include)

src/sql/backend_provider.cpp

@@ -0,0 +1,46 @@
+#include "matador/sql/backend_provider.hpp"
+
+#include <cstdint>
+#include <stdexcept>
+#include <utility>
+
+namespace matador::sql {
+backend_provider::backend_provider(std::string backends_path)
+: backends_path_(std::move(backends_path)) {}
+
+connection_impl *backend_provider::create_connection(const std::string &connection_type)
+{
+  auto it = backends_.find(connection_type);
+  if (it == backends_.end()) {
+    it = backends_.emplace(connection_type, backend_context{connection_type, backends_path_}).first;
+  }
+  return (*it->second.create_connection)();
+}
+
+const dialect &backend_provider::connection_dialect(const std::string &connection_type)
+{
+  auto it = backends_.find(connection_type);
+  if (it == backends_.end()) {
+    it = backends_.emplace(connection_type, backend_context{connection_type, backends_path_}).first;
+  }
+  return *(*it->second.get_dialect)();
+}
+
+backend_provider::backend_context::backend_context(const std::string &connection_type,
+                                                   const std::string &backends_path)
+{
+  if (!lib.load(backends_path + "matador-" + connection_type)) {
+    throw std::runtime_error("couldn't load library '" + connection_type + "'");
+  }
+
+  create_connection = reinterpret_cast<create_func>(reinterpret_cast<std::uintptr_t>(lib.function("create_database")));
+  destroy_connection = reinterpret_cast<destroy_func>(reinterpret_cast<std::uintptr_t>(lib.function("destroy_database")));
+  get_dialect = reinterpret_cast<dialect_func >(reinterpret_cast<std::uintptr_t>(lib.function("get_dialect")));
+}
+
+backend_provider::backend_context::~backend_context()
+{
+  lib.unload();
+}
+
+}

src/sql/dialect.cpp

@@ -3,6 +3,26 @@
 #include "matador/utils/string.hpp"
 
 namespace matador::sql {
+
+dialect::dialect(const dialect::token_to_string_map &token_replace_map, const dialect::data_type_to_string_map &data_type_replace_map)
+{
+  for (const auto &token : token_replace_map) {
+    tokens_[token.first] = token.second;
+  }
+
+  for (const auto &data_type : data_type_replace_map) {
+    data_types_[data_type.first] = data_type.second;
+  }
+}
+
+dialect::dialect(const dialect::data_type_to_string_map &data_type_replace_map)
+: dialect({}, data_type_replace_map)
+{}
+
+dialect::dialect(const dialect::token_to_string_map &token_replace_map)
+: dialect(token_replace_map, {})
+{}
+
 const std::string& dialect::token_at(dialect::token_t token) const
 {
   return tokens_.at(token);

src/utils/os.cpp

@@ -0,0 +1,24 @@
+#include "matador/utils/os.hpp"
+
+#include <stdexcept>
+
+namespace matador::utils::os {
+
+std::string getenv(const char *name) {
+#ifdef _WIN32
+  char var[1024];
+  size_t len{};
+  const auto error = getenv_s(&len, var, 1024, name);
+  if (error > 0) {
+    throw std::logic_error("failed to get environment variable");
+  };
+  return var;
+#else
+  return ::getenv(name);
+#endif
+}
+
+[[maybe_unused]] std::string getenv(const std::string &name) {
+  return getenv(name.c_str());
+}
+}