projects / lttng-tools.git / blame
| Commit | Line | Data |
|---|---|---|
| 8802d23b JG |
1 | /* |
| 2 | * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
| 3 | * | |
| 4 | * SPDX-License-Identifier: LGPL-2.1-only | |
| 5 | * | |
| 6 | */ | |
| 7 | ||
| 8 | #ifndef LTTNG_MAKE_UNIQUE_WRAPPER_H | |
| 9 | #define LTTNG_MAKE_UNIQUE_WRAPPER_H | |
| 10 | ||
| 11 | #include <common/macros.hpp> | |
| 12 | ||
| 13 | #include <memory> | |
| 14 | ||
| 15 | namespace lttng { | |
| 16 | ||
| 17 | /* | |
| 18 | * make_unique_wrapper is intended to facilitate the use of std::unique_ptr | |
| 19 | * to wrap C-style APIs that don't provide RAII resource management facilities. | |
| 20 | * | |
| 21 | * Usage example: | |
| 22 | * | |
| 23 | * // API | |
| 24 | * struct my_c_struct { | |
| 25 | * // ... | |
| 26 | * }; | |
| 27 | * | |
| 28 | * struct my_c_struct *create_my_c_struct(void); | |
| 29 | * void destroy_my_c_struct(struct my_c_struct *value); | |
| 30 | * | |
| 31 | * // Creating a unique_ptr to my_c_struct. | |
| 32 | * auto safe_c_struct = | |
| 33 | * lttng::make_unique_wrapper<my_c_struct, destroy_my_c_struct>( | |
| 34 | * create_my_c_struct()); | |
| 35 | * | |
| 36 | * Note that this facility is intended for use in the scope of a function. | |
| 37 | * If you need to return this unique_ptr instance, you should consider writting | |
| 38 | * a proper, idiomatic, wrapper. | |
| 39 | */ | |
| 40 | ||
| 41 | namespace details | |
| 42 | { | |
| 43 | template <typename WrappedType, void (*DeleterFunction)(WrappedType *)> | |
| 44 | struct create_unique_class { | |
| 45 | struct deleter { | |
| 46 | void operator()(WrappedType *instance) const | |
| 47 | { | |
| 48 | DeleterFunction(instance); | |
| 49 | } | |
| 50 | }; | |
| 51 | ||
| 52 | std::unique_ptr<WrappedType, deleter> operator()(WrappedType *instance) const | |
| 53 | { | |
| 54 | return std::unique_ptr<WrappedType, deleter>(instance); | |
| 55 | } | |
| 56 | }; | |
| 57 | } /* namespace details */ | |
| 58 | ||
| 59 | /* | |
| 60 | * 'free' is a utility function for use with make_unique_wrapper. It makes it easier to | |
| 61 | * wrap raw pointers that have to be deleted with `free`. Using libc's 'free' as | |
| 62 | * a make_unique_wrapper template argument will result in an error as 'WrappedType *' will | |
| 63 | * not match free's 'void *' argument. | |
| 64 | */ | |
| 65 | template <class Type> | |
| 66 | void free(Type *ptr) | |
| 67 | { | |
| 68 | std::free(ptr); | |
| 69 | } | |
| 70 | ||
| 71 | template <typename WrappedType, void (*DeleterFunc)(WrappedType *)> | |
| 72 | std::unique_ptr<WrappedType, typename details::create_unique_class<WrappedType, DeleterFunc>::deleter> | |
| 73 | make_unique_wrapper(WrappedType *instance) | |
| 74 | { | |
| 75 | const details::create_unique_class<WrappedType, DeleterFunc> unique_deleter; | |
| 76 | ||
| 77 | return unique_deleter(instance); | |
| 78 | } | |
| 79 | ||
| 80 | } /* namespace lttng */ | |
| 81 | ||
| 82 | #endif /* LTTNG_MAKE_UNIQUE_WRAPPER_H */ |