takashi kadono / Mbed OS Nucleo446_SSD1331

Color Oled(SSD1331) connect to STMicroelectronics Nucleo-F466

Dependencies:   ssd1331

mbed-os/platform/NonCopyable.h@3:f3764f852aa8, 2018-10-11 (annotated)

Committer:
kadonotakashi
Date:
Thu Oct 11 02:27:46 2018 +0000
Revision:
3:f3764f852aa8
Parent:
0:8fdf9a60065b 
Nucreo 446 + SSD1331 test version;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kadonotakashi 0:8fdf9a60065b 1 /* Copyright (c) 2017 ARM Limited
kadonotakashi 0:8fdf9a60065b 2 *
kadonotakashi 0:8fdf9a60065b 3 * Licensed under the Apache License, Version 2.0 (the "License");
kadonotakashi 0:8fdf9a60065b 4 * you may not use this file except in compliance with the License.
kadonotakashi 0:8fdf9a60065b 5 * You may obtain a copy of the License at
kadonotakashi 0:8fdf9a60065b 6 *
kadonotakashi 0:8fdf9a60065b 7 * http://www.apache.org/licenses/LICENSE-2.0
kadonotakashi 0:8fdf9a60065b 8 *
kadonotakashi 0:8fdf9a60065b 9 * Unless required by applicable law or agreed to in writing, software
kadonotakashi 0:8fdf9a60065b 10 * distributed under the License is distributed on an "AS IS" BASIS,
kadonotakashi 0:8fdf9a60065b 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
kadonotakashi 0:8fdf9a60065b 12 * See the License for the specific language governing permissions and
kadonotakashi 0:8fdf9a60065b 13 * limitations under the License.
kadonotakashi 0:8fdf9a60065b 14 */
kadonotakashi 0:8fdf9a60065b 15
kadonotakashi 0:8fdf9a60065b 16 #ifndef MBED_NONCOPYABLE_H_
kadonotakashi 0:8fdf9a60065b 17 #define MBED_NONCOPYABLE_H_
kadonotakashi 0:8fdf9a60065b 18
kadonotakashi 0:8fdf9a60065b 19 #if (!defined(MBED_DEBUG) && (MBED_CONF_PLATFORM_FORCE_NON_COPYABLE_ERROR == 0))
kadonotakashi 0:8fdf9a60065b 20 #include "mbed_toolchain.h"
kadonotakashi 0:8fdf9a60065b 21 #include "mbed_debug.h"
kadonotakashi 0:8fdf9a60065b 22 #endif
kadonotakashi 0:8fdf9a60065b 23
kadonotakashi 0:8fdf9a60065b 24 namespace mbed {
kadonotakashi 0:8fdf9a60065b 25
kadonotakashi 0:8fdf9a60065b 26 /**
kadonotakashi 0:8fdf9a60065b 27 * Inheriting from this class autogeneration of copy construction and copy
kadonotakashi 0:8fdf9a60065b 28 * assignment operations.
kadonotakashi 0:8fdf9a60065b 29 *
kadonotakashi 0:8fdf9a60065b 30 * Classes which are not value type should inherit privately from this class
kadonotakashi 0:8fdf9a60065b 31 * to avoid generation of invalid copy constructor or copy assignment operator
kadonotakashi 0:8fdf9a60065b 32 * which can lead to unnoticeable programming errors.
kadonotakashi 0:8fdf9a60065b 33 *
kadonotakashi 0:8fdf9a60065b 34 * As an example consider the following signature:
kadonotakashi 0:8fdf9a60065b 35 *
kadonotakashi 0:8fdf9a60065b 36 * @code
kadonotakashi 0:8fdf9a60065b 37 * class Resource;
kadonotakashi 0:8fdf9a60065b 38 *
kadonotakashi 0:8fdf9a60065b 39 * class Foo {
kadonotakashi 0:8fdf9a60065b 40 * public:
kadonotakashi 0:8fdf9a60065b 41 * Foo() : _resource(new Resource()) { }
kadonotakashi 0:8fdf9a60065b 42 * ~Foo() { delete _resource; }
kadonotakashi 0:8fdf9a60065b 43 * private:
kadonotakashi 0:8fdf9a60065b 44 * Resource* _resource;
kadonotakashi 0:8fdf9a60065b 45 * }
kadonotakashi 0:8fdf9a60065b 46 *
kadonotakashi 0:8fdf9a60065b 47 * Foo get_foo();
kadonotakashi 0:8fdf9a60065b 48 *
kadonotakashi 0:8fdf9a60065b 49 * Foo foo = get_foo();
kadonotakashi 0:8fdf9a60065b 50 * @endcode
kadonotakashi 0:8fdf9a60065b 51 *
kadonotakashi 0:8fdf9a60065b 52 * There is a bug in this function, it returns a temporary value which will be
kadonotakashi 0:8fdf9a60065b 53 * byte copied into foo then destroyed. Unfortunately, internally the Foo class
kadonotakashi 0:8fdf9a60065b 54 * manage a pointer to a Resource object. This pointer will be released when the
kadonotakashi 0:8fdf9a60065b 55 * temporary is destroyed and foo will manage a pointer to an already released
kadonotakashi 0:8fdf9a60065b 56 * Resource.
kadonotakashi 0:8fdf9a60065b 57 *
kadonotakashi 0:8fdf9a60065b 58 * Two issues has to be fixed in the example above:
kadonotakashi 0:8fdf9a60065b 59 * - Function signature has to be changed to reflect the fact that Foo
kadonotakashi 0:8fdf9a60065b 60 * instances cannot be copied. In that case accessor should return a
kadonotakashi 0:8fdf9a60065b 61 * reference to give access to objects already existing and managed.
kadonotakashi 0:8fdf9a60065b 62 * Generator on the other hand should return a pointer to the created object.
kadonotakashi 0:8fdf9a60065b 63 *
kadonotakashi 0:8fdf9a60065b 64 * @code
kadonotakashi 0:8fdf9a60065b 65 * // return a reference to an already managed Foo instance
kadonotakashi 0:8fdf9a60065b 66 * Foo& get_foo();
kadonotakashi 0:8fdf9a60065b 67 * Foo& foo = get_foo();
kadonotakashi 0:8fdf9a60065b 68 *
kadonotakashi 0:8fdf9a60065b 69 * // create a new Foo instance
kadonotakashi 0:8fdf9a60065b 70 * Foo* make_foo();
kadonotakashi 0:8fdf9a60065b 71 * Foo* m = make_foo();
kadonotakashi 0:8fdf9a60065b 72 * @endcode
kadonotakashi 0:8fdf9a60065b 73 *
kadonotakashi 0:8fdf9a60065b 74 * - Copy constructor and copy assignment operator has to be made private
kadonotakashi 0:8fdf9a60065b 75 * in the Foo class. It prevents unwanted copy of Foo objects. This can be
kadonotakashi 0:8fdf9a60065b 76 * done by declaring copy constructor and copy assignment in the private
kadonotakashi 0:8fdf9a60065b 77 * section of the Foo class.
kadonotakashi 0:8fdf9a60065b 78 *
kadonotakashi 0:8fdf9a60065b 79 * @code
kadonotakashi 0:8fdf9a60065b 80 * class Foo {
kadonotakashi 0:8fdf9a60065b 81 * public:
kadonotakashi 0:8fdf9a60065b 82 * Foo() : _resource(new Resource()) { }
kadonotakashi 0:8fdf9a60065b 83 * ~Foo() { delete _resource; }
kadonotakashi 0:8fdf9a60065b 84 * private:
kadonotakashi 0:8fdf9a60065b 85 * // disallow copy operations
kadonotakashi 0:8fdf9a60065b 86 * Foo(const Foo&);
kadonotakashi 0:8fdf9a60065b 87 * Foo& operator=(const Foo&);
kadonotakashi 0:8fdf9a60065b 88 * // data members
kadonotakashi 0:8fdf9a60065b 89 * Resource* _resource;
kadonotakashi 0:8fdf9a60065b 90 * }
kadonotakashi 0:8fdf9a60065b 91 * @endcode
kadonotakashi 0:8fdf9a60065b 92 *
kadonotakashi 0:8fdf9a60065b 93 * Another solution is to inherit privately from the NonCopyable class.
kadonotakashi 0:8fdf9a60065b 94 * It reduces the boiler plate needed to avoid copy operations but more
kadonotakashi 0:8fdf9a60065b 95 * importantly it clarifies the programmer intent and the object semantic.
kadonotakashi 0:8fdf9a60065b 96 *
kadonotakashi 0:8fdf9a60065b 97 * class Foo : private NonCopyable<Foo> {
kadonotakashi 0:8fdf9a60065b 98 * public:
kadonotakashi 0:8fdf9a60065b 99 * Foo() : _resource(new Resource()) { }
kadonotakashi 0:8fdf9a60065b 100 * ~Foo() { delete _resource; }
kadonotakashi 0:8fdf9a60065b 101 * private:
kadonotakashi 0:8fdf9a60065b 102 * Resource* _resource;
kadonotakashi 0:8fdf9a60065b 103 * }
kadonotakashi 0:8fdf9a60065b 104 *
kadonotakashi 0:8fdf9a60065b 105 * @tparam T The type that should be made non copyable. It prevent cases where
kadonotakashi 0:8fdf9a60065b 106 * the empty base optimization cannot be applied and therefore ensure that the
kadonotakashi 0:8fdf9a60065b 107 * cost of this semantic sugar is null.
kadonotakashi 0:8fdf9a60065b 108 *
kadonotakashi 0:8fdf9a60065b 109 * As an example, the empty base optimization is prohibited if one of the empty
kadonotakashi 0:8fdf9a60065b 110 * base class is also a base type of the first non static data member:
kadonotakashi 0:8fdf9a60065b 111 *
kadonotakashi 0:8fdf9a60065b 112 * @code
kadonotakashi 0:8fdf9a60065b 113 * struct A { };
kadonotakashi 0:8fdf9a60065b 114 * struct B : A {
kadonotakashi 0:8fdf9a60065b 115 * int foo;
kadonotakashi 0:8fdf9a60065b 116 * };
kadonotakashi 0:8fdf9a60065b 117 * // thanks to empty base optimization, sizeof(B) == sizeof(int)
kadonotakashi 0:8fdf9a60065b 118 *
kadonotakashi 0:8fdf9a60065b 119 * struct C : A {
kadonotakashi 0:8fdf9a60065b 120 * B b;
kadonotakashi 0:8fdf9a60065b 121 * };
kadonotakashi 0:8fdf9a60065b 122 *
kadonotakashi 0:8fdf9a60065b 123 * // empty base optimization cannot be applied here because A from C and A from
kadonotakashi 0:8fdf9a60065b 124 * // B shall have a different address. In that case, with the alignment
kadonotakashi 0:8fdf9a60065b 125 * // sizeof(C) == 2* sizeof(int)
kadonotakashi 0:8fdf9a60065b 126 * @endcode
kadonotakashi 0:8fdf9a60065b 127 *
kadonotakashi 0:8fdf9a60065b 128 * The solution to that problem is to templatize the empty class to makes it
kadonotakashi 0:8fdf9a60065b 129 * unique to the type it is applied to:
kadonotakashi 0:8fdf9a60065b 130 *
kadonotakashi 0:8fdf9a60065b 131 * @code
kadonotakashi 0:8fdf9a60065b 132 * template<typename T>
kadonotakashi 0:8fdf9a60065b 133 * struct A<T> { };
kadonotakashi 0:8fdf9a60065b 134 * struct B : A<B> {
kadonotakashi 0:8fdf9a60065b 135 * int foo;
kadonotakashi 0:8fdf9a60065b 136 * };
kadonotakashi 0:8fdf9a60065b 137 * struct C : A<C> {
kadonotakashi 0:8fdf9a60065b 138 * B b;
kadonotakashi 0:8fdf9a60065b 139 * };
kadonotakashi 0:8fdf9a60065b 140 *
kadonotakashi 0:8fdf9a60065b 141 * // empty base optimization can be applied B and C does not refer to the same
kadonotakashi 0:8fdf9a60065b 142 * // kind of A. sizeof(C) == sizeof(B) == sizeof(int).
kadonotakashi 0:8fdf9a60065b 143 * @endcode
kadonotakashi 0:8fdf9a60065b 144 *
kadonotakashi 0:8fdf9a60065b 145 * @note Compile time errors are disabled if the develop or the release profile
kadonotakashi 0:8fdf9a60065b 146 * is used. To override this behavior and force compile time errors in all profile
kadonotakashi 0:8fdf9a60065b 147 * set the configuration parameter "platform.force-non-copyable-error" to true.
kadonotakashi 0:8fdf9a60065b 148 */
kadonotakashi 0:8fdf9a60065b 149 template<typename T>
kadonotakashi 0:8fdf9a60065b 150 class NonCopyable {
kadonotakashi 0:8fdf9a60065b 151 protected:
kadonotakashi 0:8fdf9a60065b 152 /**
kadonotakashi 0:8fdf9a60065b 153 * Disallow construction of NonCopyable objects from outside of its hierarchy.
kadonotakashi 0:8fdf9a60065b 154 */
kadonotakashi 0:8fdf9a60065b 155 NonCopyable() { }
kadonotakashi 0:8fdf9a60065b 156 /**
kadonotakashi 0:8fdf9a60065b 157 * Disallow destruction of NonCopyable objects from outside of its hierarchy.
kadonotakashi 0:8fdf9a60065b 158 */
kadonotakashi 0:8fdf9a60065b 159 ~NonCopyable() { }
kadonotakashi 0:8fdf9a60065b 160
kadonotakashi 0:8fdf9a60065b 161 #if (!defined(MBED_DEBUG) && (MBED_CONF_PLATFORM_FORCE_NON_COPYABLE_ERROR == 0))
kadonotakashi 0:8fdf9a60065b 162 /**
kadonotakashi 0:8fdf9a60065b 163 * NonCopyable copy constructor.
kadonotakashi 0:8fdf9a60065b 164 *
kadonotakashi 0:8fdf9a60065b 165 * A compile time warning is issued when this function is used and a runtime
kadonotakashi 0:8fdf9a60065b 166 * warning is printed when the copy construction of the non copyable happens.
kadonotakashi 0:8fdf9a60065b 167 *
kadonotakashi 0:8fdf9a60065b 168 * If you see this warning, your code is probably doing something unspecified.
kadonotakashi 0:8fdf9a60065b 169 * Copy of non copyable resources can lead to resource leak and random error.
kadonotakashi 0:8fdf9a60065b 170 */
kadonotakashi 0:8fdf9a60065b 171 MBED_DEPRECATED("Invalid copy construction of a NonCopyable resource.")
kadonotakashi 0:8fdf9a60065b 172 NonCopyable(const NonCopyable &)
kadonotakashi 0:8fdf9a60065b 173 {
kadonotakashi 0:8fdf9a60065b 174 debug("Invalid copy construction of a NonCopyable resource: %s\r\n", MBED_PRETTY_FUNCTION);
kadonotakashi 0:8fdf9a60065b 175 }
kadonotakashi 0:8fdf9a60065b 176
kadonotakashi 0:8fdf9a60065b 177 /**
kadonotakashi 0:8fdf9a60065b 178 * NonCopyable copy assignment operator.
kadonotakashi 0:8fdf9a60065b 179 *
kadonotakashi 0:8fdf9a60065b 180 * A compile time warning is issued when this function is used and a runtime
kadonotakashi 0:8fdf9a60065b 181 * warning is printed when the copy construction of the non copyable happens.
kadonotakashi 0:8fdf9a60065b 182 *
kadonotakashi 0:8fdf9a60065b 183 * If you see this warning, your code is probably doing something unspecified.
kadonotakashi 0:8fdf9a60065b 184 * Copy of non copyable resources can lead to resource leak and random error.
kadonotakashi 0:8fdf9a60065b 185 */
kadonotakashi 0:8fdf9a60065b 186 MBED_DEPRECATED("Invalid copy assignment of a NonCopyable resource.")
kadonotakashi 0:8fdf9a60065b 187 NonCopyable &operator=(const NonCopyable &)
kadonotakashi 0:8fdf9a60065b 188 {
kadonotakashi 0:8fdf9a60065b 189 debug("Invalid copy assignment of a NonCopyable resource: %s\r\n", MBED_PRETTY_FUNCTION);
kadonotakashi 0:8fdf9a60065b 190 return *this;
kadonotakashi 0:8fdf9a60065b 191 }
kadonotakashi 0:8fdf9a60065b 192
kadonotakashi 0:8fdf9a60065b 193 #else
kadonotakashi 0:8fdf9a60065b 194 private:
kadonotakashi 0:8fdf9a60065b 195 /**
kadonotakashi 0:8fdf9a60065b 196 * Declare copy constructor as private, any attempt to copy construct
kadonotakashi 0:8fdf9a60065b 197 * a NonCopyable will fail at compile time.
kadonotakashi 0:8fdf9a60065b 198 */
kadonotakashi 0:8fdf9a60065b 199 NonCopyable(const NonCopyable &);
kadonotakashi 0:8fdf9a60065b 200
kadonotakashi 0:8fdf9a60065b 201 /**
kadonotakashi 0:8fdf9a60065b 202 * Declare copy assignment operator as private, any attempt to copy assign
kadonotakashi 0:8fdf9a60065b 203 * a NonCopyable will fail at compile time.
kadonotakashi 0:8fdf9a60065b 204 */
kadonotakashi 0:8fdf9a60065b 205 NonCopyable &operator=(const NonCopyable &);
kadonotakashi 0:8fdf9a60065b 206 #endif
kadonotakashi 0:8fdf9a60065b 207 };
kadonotakashi 0:8fdf9a60065b 208
kadonotakashi 0:8fdf9a60065b 209 } // namespace mbed
kadonotakashi 0:8fdf9a60065b 210
kadonotakashi 0:8fdf9a60065b 211 #endif /* MBED_NONCOPYABLE_H_ */