# FFI Bridge Documentation

## Overview

The APT Wrapper provides a C++ Foreign Function Interface (FFI) bridge for integration with C++ applications, particularly designed for apt-ostree.

## C++ Integration

### Header File

The bridge requires a C++ header file `apt-wrapper/bridge.h` that defines the C++ side of the interface.

### AptPackage FFI

The `AptPackage` struct can be used across the FFI boundary:

```cpp
// C++ side
#include "apt-wrapper/bridge.h"

// Create package from Rust
AptPackage package = new_ffi("vim", "2:8.1.2269-1ubuntu5", "Vi IMproved", true);

// Access package properties
std::string name = package.name();
std::string version = package.version();
std::string description = package.description();
bool installed = package.is_installed();
```

### Rust Side Functions

```rust
// Rust side - these functions are exposed to C++
pub fn new_ffi(name: String, version: String, description: String, installed: bool) -> AptPackage;
pub fn name_ffi(package: &AptPackage) -> &str;
pub fn version_ffi(package: &AptPackage) -> &str;
pub fn description_ffi(package: &AptPackage) -> &str;
pub fn is_installed_ffi(package: &AptPackage) -> bool;
```

## Usage in C++ Projects

1. Include the generated header file
2. Link against the Rust library
3. Use the FFI functions to interact with APT packages

## Dependencies

- `cxx` crate for FFI generation
- C++ compiler with C++17 support