C++ Coding Standards

Relevant source files

The following files were used as context for generating this wiki page:

• documents/CodingStandards/CppStyle.md
• include/HXLibs/macro/NoWarring.hpp
• include/HXLibs/net/protocol/http/Http.hpp
• tests/reflection/02_refl_macro.cpp
• CMakeLists.txt
• include/HXLibs/net/protocol/http/MimeType.hpp

C++ Coding Standards define the structural and stylistic requirements for the HXLibs project. The project requires a minimum of C++20 and encourages modern programming practices to ensure cross-platform compatibility and maintainability.

Sources: documents/CodingStandards/CppStyle.md:1-5, CMakeLists.txt:1-10

Naming Conventions

The project enforces specific naming patterns for different code entities to maintain consistency across the codebase.

File and Namespace Naming

• File Names: Use CamelCase (e.g., IoUringLoop.h).
• Extensions: Use .hpp for files containing templates and .h for files without templates.
• Namespaces: Match the folder structure. For example, code in /HXLibs/coroutine/ resides in the HX::coroutine namespace. Sub-modules use a nested internal namespace for implementation details.

Sources: documents/CodingStandards/CppStyle.md:7-10, documents/CodingStandards/CppStyle.md:27-37

Identifier Naming

• Class Members: Prefix with an underscore (e.g., _name).
• Variables: Use camelCase for almost all variables.
• Enums: Use PascalCase (e.g., HttpContentType::Html).
• Constants: Use camelCase, optionally prefixed with k (e.g., kMaxRetry).
• Macros: Use uppercase with underscores. Public library macros use the HX_{NAME} pattern. Private internal macros use the _hx_MACRO_{NAME}__ pattern.

Sources: documents/CodingStandards/CppStyle.md:39-47, include/HXLibs/net/protocol/http/MimeType.hpp:370-380

Code Structure and Formatting

Include Guards and Headers

The project uses #pragma once as the standard mechanism to prevent header re-definition. The include order follows a specific hierarchy:

1. Paired .h and .cpp files.
2. System/Standard libraries (sorted by extensionless headers last).
3. Third-party libraries (e.g., OpenSSL).
4. Project platform-specific API headers.
5. Project library files.

Sources: documents/CodingStandards/CppStyle.md:12-25, documents/CodingStandards/CppStyle.md:75-77

Indentation and Formatting

• Indentation: Use 4 spaces.
• Tabs: Convert all tab characters to 4 spaces.

Sources: documents/CodingStandards/CppStyle.md:73-73

Compilation and Reserved Identifiers

The build system uses Clang-specific flags to detect the use of reserved identifiers and macros.

if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "AppleClang")
    add_compile_options(
        -Wpedantic
        -Wreserved-id-macro
        -Wreserved-identifier
    )
endif()

Sources: documents/CodingStandards/CppStyle.md:53-62

Macro Management

The library provides specialized macros to manage compiler warnings across different platforms (MSVC, Clang, GCC).

Macro	Description
HX_NO_WARNINGS_BEGIN	Disables common warnings like -Wall, -Wextra, and -Wpedantic.
HX_NO_WARNINGS_END	Restores previous warning levels using compiler-specific push/pop pragmas.
HX_NO_MAYBE_UNINITIALIZED_WARNINGS_BEGIN	Specifically targets GCC's -Wmaybe-uninitialized noise.

Sources: include/HXLibs/macro/NoWarring.hpp:18-58

Reflection Macros

Project-specific macros facilitate reflection of struct and class members, allowing access to private variables.

The HX_REFL macro exposes members using their actual names, while HX_REFL_AS allows mapping internal member names to public aliases for serialization.

Sources: tests/reflection/02_refl_macro.cpp:11-76

String and Resource Handling

The project standardizes the use of std::string_view for efficient string handling and case-insensitive operations.

Case-Insensitive Comparisons

Internal utilities provide transparent hash and equality comparators for std::unordered_map keys, enabling lookups via std::string_view without allocation.

MIME Type Mapping

MIME types are defined in a static map using std::string_view for both keys (file extensions) and values (content types).

Sources: include/HXLibs/net/protocol/http/MimeType.hpp:38-360

Conclusion

HXLibs adheres to strict C++20 standards, prioritizing modern language features and consistent naming. These standards ensure that the asynchronous network components and reflection systems remain performant and portable across various compilers and environments.