boost-ext.di

Your C++14 one header only Dependency Injection library with no dependencies

https://www.youtube.com/watch?v=yVogS4NbL6U

Quick start

Download

boost-ext.di requires only one file. Get the latest header here!

Include

#include <boost/di.hpp>
namespace di = boost::di;

Compile

• GCC/Clang sh $CXX -std=c++14 -O2 -fno-exceptions -fno-rtti -Wall -Werror -pedantic-errors file.cpp
• MSVC sh cl /std:c++14 /Ox /W3 file.cpp

Quick guide - Create object graph

class ctor {
public:
  explicit ctor(int i) : i(i) {}
  int i;
};

struct aggregate {
  double d;
};

class example {
 public:
  example(aggregate a, const ctor& c) {
    assert(87.0 == a.d);
    assert(42 == c.i);
  };
};

int main() {
  const auto injector = di::make_injector(
    di::bind<int>.to(42),
    di::bind<double>.to(87.0)
  );

  injector.create<example>();
}

Run this example on Wandbox.

xor eax, eax
retq
      

Quick guide - Bind interfaces

struct interface {
  virtual ~interface() noexcept = default;
  virtual int get() const = 0;
};

class implementation : public interface {
public:
  int get() const override { return 42; }
};

struct example {
  example(std::shared_ptr<interface> i) {
    assert(42 == i->get());
  }
};

int main() {
  const auto injector = di::make_injector(
    di::bind<interface>.to<implementation>()
  );

  injector.create<std::unique_ptr<example>>();
}

Run this example on Wandbox.

push   %rbx
mov    %rdi,%rbx
mov    $0x8,%edi
callq  0x4008e0 <_Znwm@plt>
movq   $0x400c78,(%rax)
mov    %rax,(%rbx)
mov    %rbx,%rax
pop    %rbx
retq
      

Quick guide - Bind templates

template<class ErrorPolicy = class TErrorPolicy>
class simple_updater {
public:
  void update() const {
    ErrorPolicy::on("update");
  }
};

template<class Updater = class TUpdater>
class example {
public:
  explicit example(const Updater& updater)
    : updater(updater)
  { }

  void update() {
    updater.update();
  }

private:
  const Updater& updater;
};

int main() {
  struct throw_policy {
    static void on(const std::string& str) {
      throw std::runtime_error(str);
    }
  };

  const auto injector = di::make_injector(
    di::bind<class TErrorPolicy>.to<throw_policy>(),
    di::bind<class TUpdater>.to<simple_updater>()
  );

  injector.create<example>().update();
  // Terminates with an uncaught exception because of our bound error policy
}

Run this example on Wandbox.

xor eax, eax
retq
      

Quick guide - Bind concepts

struct Streamable {
 template<class T>
 auto requires(T&& t) -> decltype(
   int( t.read() ),
   t.write(int)
 );
};

template<class Exchange = Streamable(class ExchangeStream)
         class Engine   = Streamable(class EngineStream)>
class example {
public:
  example(Exchange exchange, Engine engine)
    : exchange(std::move(exchange)), engine(std::move(engine))
  { }

private:
  Exchange exchange;
  Engine engine;
};

int main() {
  const auto injector = di::make_injector(
    di::bind<Streamable(class ExchangeStream)>.to<exchange>(),
    di::bind<Streamable(class EngineStream)>.to<engine>()
  );

  injector.create<example>();
}

Run this example on Wandbox.

xor eax, eax
retq
      

Documentation

• Introduction
  • Do I use a Dependency Injection already?
  • Do I use Dependency Injection correctly?
  • Do I need a Dependency Injection?
  • STUPID vs SOLID - "Clean Code" Uncle Bob
  • Do I need a DI Framework/Library?
  • Manual DI - Wiring Mess (Avoid it by using [Boost].DI)
  • Real Life examples?
  • Why [Boost].DI?
  • [Boost].DI design goals
  • Articles
  • Videos
  • [Boost::ext].DI
  • Dependency Injection In General
  • Acknowledgements
• Overview
  • Quick Start
  • Dependencies
  • Supported/Tested compilers
  • Configuration
  • Exception Safety
  • Thread Safety
  • Error Messages
  • Performance
• Tutorial
  • 0. [Pre] Refactor towards DI
  • 1. [Basic] Create objects tree
  • 2. [Basic] First steps with bindings
  • 3. [Basic] Decide the life times
  • 4. [Basic] Annotations to the rescue
  • 5. [Basic] Split your configuration
  • 6. [Advanced] Dump/Limit your types
  • 7. [Advanced] Customize it
  • 8. [Advanced] Extend it
• Try It Online!
• Benchmarks
  • Performance
  • C++ Libraries
  • C++ vs Java vs CLibraries
  • Usage of C++ vs Java vs CLibraries
• User Guide
  • Injector
  • Bindings
  • Injections
  • Annotations
  • Scopes
  • Modules
  • Providers
  • Policies
  • Concepts
  • Configuration
• Examples
  • Hello World
  • Bindings
  • Dynamic Bindings
  • Forward Bindings
  • Is Creatable
  • Multiple Bindings
  • Binding Non-owning Pointer
  • Binding Templates
  • Binding To Constructor
  • Automatic Injection
  • Constructor Signature
  • Constructor Injection
  • Multiple Interface
  • Annotations
  • Deduce Scope
  • Custom Scope
  • Eager Singletons
  • Modules
  • Modules (hpp/cpp)
  • Custom Policy
  • Custom Provider
  • Pool Provider
  • Configuration
  • Polymorphism
  • Inheritance
  • Type Erasure
  • Function
  • Variant
  • Templates
  • Concepts
• Extensions
  • Injector
  • Constructor Bindings
  • Contextual Bindings
  • [Assisted Injection](http