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/*
* SPDX-License-Identifier: GPL-2.0-or-later
* SPDX-FileName: Function.h
* SPDX-FileContributor: Dmitry Vedenko
*/
#pragma once
#include <functional>
#include <string>
#include <string_view>
#include <tuple>
#include <type_traits>
struct sqlite3;
struct sqlite3_value;
struct sqlite3_context;
namespace audacity::sqlite
{
namespace details
{
using SQLiteFunctorWithArgs =
std::function<void(sqlite3_context*, int, sqlite3_value**)>;
using SQLiteFunctor= std::function<void(sqlite3_context*)>;
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, bool& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, int& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, unsigned int& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, long& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, unsigned long& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, long long& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, unsigned long long& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, double& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, float& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, std::string& result);
SQLITE_HELPERS_API void FromSQLiteValue(sqlite3_value& value, std::string_view& result);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, bool value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, int value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, unsigned int value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, long value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, unsigned long value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, long long value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, unsigned long long value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, double value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, float value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, const std::string& value);
SQLITE_HELPERS_API void SetSQLiteFunctionResult(sqlite3_context* context, const std::string_view& value);
SQLITE_HELPERS_API void
SetSQLiteFunctionError(sqlite3_context* context, const std::string_view& error);
template<typename T>
std::decay_t<T> FromSQLiteValue(sqlite3_value& value)
{
std::decay_t<T> result;
FromSQLiteValue(value, result);
return result;
}
template<typename... Args, std::size_t... Is>
auto SQLiteValuesToTuple(sqlite3_value** values, std::index_sequence<Is...>)
{
return std::make_tuple(FromSQLiteValue<Args>(*values[Is])...);
}
template <typename CallbackType>
struct SQLiteFunction {};
template<typename R, typename... Args>
struct SQLiteFunction<std::function<R(Args...)>>
{
static constexpr std::size_t Arity = sizeof...(Args);
static SQLiteFunctorWithArgs ToSQLiteFunctorWithArgs(std::function<R(Args...)> callback)
{
return [function = std::move(callback)](
sqlite3_context* context, int argc, sqlite3_value** argv)
{
if (argc != sizeof...(Args))
{
SetSQLiteFunctionError(context, "Invalid number of arguments");
return;
}
if constexpr (std::is_same_v<R, void>)
{
std::apply(
function, SQLiteValuesToTuple<Args...>(
argv, std::make_index_sequence<sizeof...(Args)>()));
}
else
{
SetSQLiteFunctionResult(
context,
std::apply(
function,
SQLiteValuesToTuple<Args...>(
argv, std::make_index_sequence<sizeof...(Args)>())));
}
};
}
};
template <typename R> struct SQLiteFunction<std::function<R()>>
{
static SQLiteFunctor ToSQLiteFunctor(std::function<R()> callback)
{
return [function = std::move(callback)](sqlite3_context* context)
{
if constexpr (std::is_same_v<R, void>)
function();
else
SetSQLiteFunctionResult(context, function());
};
}
};
template<typename CallbackType>
auto MakeSQLiteFunctorWithArgs(CallbackType callback)
{
using FunctionType = decltype(std::function { callback });
return SQLiteFunction<FunctionType>::ToSQLiteFunctorWithArgs(
std::move(callback));
}
template<typename CallbackType>
constexpr std::size_t GetFunctionArity()
{
using FunctionType = decltype(std::function { std::declval<CallbackType>() });
return SQLiteFunction<FunctionType>::Arity;
}
template <typename CallbackType>
auto MakeSQLiteFunctor(CallbackType callback)
{
using FunctionType = decltype(std::function { callback });
return SQLiteFunction<FunctionType>::ToSQLiteFunctor(
std::move(callback));
}
} // namespace details
//! A class representing a scalar function in a SQLite database
class SQLITE_HELPERS_API ScalarFunction final
{
template<typename ScalarFunctionType>
ScalarFunction(
sqlite3* connection, std::string name, ScalarFunctionType function)
: mConnection { connection }
, mName { std::move(name) }
, mFunctor { details::MakeSQLiteFunctorWithArgs(std::move(function)) }
{
Register(details::GetFunctionArity<ScalarFunctionType>());
}
public:
ScalarFunction() = default;
ScalarFunction(const ScalarFunction&) = delete;
ScalarFunction(ScalarFunction&&) noexcept;
ScalarFunction& operator=(const ScalarFunction&) = delete;
ScalarFunction& operator=(ScalarFunction&&) noexcept;
~ScalarFunction();
private:
void Register(std::size_t arity);
static void CallFunction(sqlite3_context* context, int argc, sqlite3_value** argv);
sqlite3* mConnection { nullptr };
std::string mName;
details::SQLiteFunctorWithArgs mFunctor;
friend class Connection;
};
//! A class representing an aggregate function in a SQLite database
class SQLITE_HELPERS_API AggregateFunction final
{
template<typename StepFunctionType, typename FinalFunctionType>
AggregateFunction(
sqlite3* connection, std::string name, StepFunctionType stepFunction,
FinalFunctionType finalFunction)
: mConnection { connection }
, mName { std::move(name) }
, mStepFunctor { details::MakeSQLiteFunctorWithArgs(
std::move(stepFunction)) }
, mFinalFunctor { details::MakeSQLiteFunctor(std::move(finalFunction)) }
{
Register(details::GetFunctionArity<StepFunctionType>());
}
public:
AggregateFunction() = default;
AggregateFunction(const AggregateFunction&) = delete;
AggregateFunction(AggregateFunction&&) noexcept;
AggregateFunction& operator=(const AggregateFunction&) = delete;
AggregateFunction& operator=(AggregateFunction&&) noexcept;
~AggregateFunction();
private:
void Register(std::size_t arity);
static void CallStepFunction (
sqlite3_context* context, int argc, sqlite3_value** argv);
static void CallFinalFunction(sqlite3_context* context);
sqlite3* mConnection { nullptr };
std::string mName;
details::SQLiteFunctorWithArgs mStepFunctor;
details::SQLiteFunctor mFinalFunctor;
friend class Connection;
};
} // namespace audacity::sqlite
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