concepts.h File Reference

C++20 concepts for database_system type validation. More...

#include <concepts>
#include <type_traits>
#include <functional>
#include <memory>
#include <string>
#include <future>

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Namespaces
namespace	database
namespace	database::core
namespace	database::concepts

Concepts
concept	database::concepts::Invocable
	A callable type that can be invoked with given arguments.
concept	database::concepts::VoidCallable
	A callable type that returns void when invoked.
concept	database::concepts::ReturnsResult
	A callable type that returns a value convertible to the specified type.
concept	database::concepts::Predicate
	A callable type that returns a boolean value.
concept	database::concepts::NoexceptCallable
	A callable type that is marked noexcept.
concept	database::concepts::DelayedCallable
	A callable suitable for delayed execution.
concept	database::concepts::AsyncCallable
	A callable suitable for async execution.
concept	database::concepts::QueryCallback
	A callable that handles query results.
concept	database::concepts::ErrorHandler
	A callable that handles database errors.
concept	database::concepts::ConnectionFactory
	A callable that creates database connections.
concept	database::concepts::BackendFactory
	A callable that creates database backends.
concept	database::concepts::StreamEventHandler
	A callable that handles stream events.
concept	database::concepts::StreamEventFilter
	A callable that filters stream events.
concept	database::concepts::TransactionAction
	A callable that represents a transaction action.
concept	database::concepts::CompensationAction
	A callable that represents a compensation (rollback) action.
concept	database::concepts::PooledResource
	A type that can be managed by a pool.
concept	database::concepts::ConnectionWrapper
	A type that wraps a database connection.
concept	database::concepts::SubmittableTask
	A callable suitable for submission to an async executor.
concept	database::concepts::VoidTask
	A callable that returns void, suitable for fire-and-forget execution.

Detailed Description

C++20 concepts for database_system type validation.

This header provides C++20 concepts for compile-time type validation specific to database operations. It re-exports common_system concepts and adds database-specific concepts.

Available concept categories:

• Callable concepts: From common_system (Invocable, VoidCallable, etc.)
• Database concepts: QueryCallback, ConnectionFactory, etc.

Requirements:

• C++20 compiler with concepts support
• GCC 10+, Clang 10+, MSVC 2019 16.3+

Benefits of using concepts:

• Clearer error messages: Template errors are displayed as concept violations instead of hundreds of lines of SFINAE failures
• Self-documenting code: Concepts express type requirements explicitly
• Better IDE support: More accurate auto-completion and type hints
• Code simplification: Eliminates std::enable_if boilerplate

Example usage:

#include "database/core/concepts.h"
 
using namespace database::concepts;
 
// Use callable concepts for async operations
template<Invocable F>
auto submit_task(F&& func) {
    return executor.submit(std::forward<F>(func));
}
 
// Use database-specific concepts
template<QueryCallback<database_result> F>
void on_query_complete(F&& callback) {
    // callback will be invoked with database_result
}

Definition in file concepts.h.