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/*
* Copyright 2014 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FRUIT_MACRO_H
#define FRUIT_MACRO_H
// This include is not required here, but having it here shortens the include trace in error messages.
#include <fruit/impl/injection_errors.h>
#include <fruit/fruit_forward_decls.h>
/**
* A convenience macro to define the Inject typedef while declaring/defining the constructor that will be used for
* injection.
* It also supports assisted injection and injection of annotated types.
*
* Example usage:
*
* class MyClass {
* public:
* INJECT(MyClass(Foo* foo, Bar* bar)) {...}
* };
*
* is equivalent to:
*
* class MyClass {
* public:
* using Inject = MyClass(Foo*, Bar*);
*
* MyClass(Foo* foo, Bar* y) {...}
* };
*
* Example usage for assisted injection (see PartialComponent::registerFactory):
*
* class MyClass {
* public:
* INJECT(MyClass(Foo* foo, ASSISTED(int) n) {...}
* };
*
* is equivalent to:
*
* class MyClass {
* public:
* using Inject = MyClass(Foo*, Assisted<int>);
*
* MyClass(Foo* foo, int n) {...}
* };
*
* Example usage for annotated types:
*
* class MyClass {
* public:
* INJECT(MyClass(ANNOTATED(SomeAnnotation, Foo*) foo, Bar* bar)) {...}
* };
*
* ASSISTED and ANNOTATED *can* be used together in the same INJECT() annotation, but they can't both be used for a
* single parameter (as this wouldn't make sense, parameters that use assisted injection are user-supplied, they aren't
* injected from a binding).
*
* NOTE: This can't be used if the constructor is templated (the class can be templated, however), if there are any
* default arguments or if the constructor is marked `explicit'.
* In those cases, define the Inject annotation manually or use registerConstructor()/registerFactory() instead.
*
* NOTE: ASSISTED takes just one argument, but it's declared as variadic to make sure that the preprocessor doesn't
* choke on multi-argument templates like the map above, that the processor is unable to parse correctly.
*
* NOTE: ASSISTED takes just 2 arguments, but it's declared as variadic to make sure that the preprocessor doesn't choke
* on multi-argument templates, that the processor is unable to parse correctly.
*
* NOTE: In addition to the public Inject typedef, two typedefs (FruitAssistedTypedef and FruitAnnotatedTypedef) will be
* defined inside the class, make sure you don't define another typedef/field/method with the same name if you use the
* INJECT macro (unlikely but possible) these typedefs are an implementation detail of Fruit and should not be used.
*
* NOTE: The return type (MyClass in this case) should not be annotated. However an annotated
* MyClass (or MyClass factory) can be injected from any INJECT declaration.
*/
#define INJECT(Signature) \
using Inject = Signature; \
\
template <typename FruitAssistedDeclarationParam> \
using FruitAssistedTypedef = FruitAssistedDeclarationParam; \
template <typename Annotation, typename FruitAnnotatedDeclarationParam> \
using FruitAnnotatedTypedef = FruitAnnotatedDeclarationParam; \
\
Signature
#define ASSISTED(...) FruitAssistedTypedef<__VA_ARGS__>
#define ANNOTATED(Annotation, ...) FruitAnnotatedTypedef<Annotation, __VA_ARGS__>
/**
* These are intentionally NOT in the fruit namespace, they can't be there for technical reasons.
*
* NOTE: don't use these directly, they're only used to implement the INJECT macro.
* Consider them part of fruit::impl.
*/
template <typename T>
using FruitAssistedTypedef = fruit::Assisted<T>;
template <typename Annotation, typename T>
using FruitAnnotatedTypedef = fruit::Annotated<Annotation, T>;
#endif // FRUIT_MACRO_H